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OAS

The Organization of American States (OAS) is the world's oldest regional organization, established by the signing of its Charter on 30 April 1948 in Bogotá, Colombia, which entered into force in December 1951, and comprising 35 independent member states from throughout the Americas to strengthen cooperation on peace, justice, solidarity, democracy, human rights, security, and development.^[1]^[2] Headquartered in Washington, D.C., the OAS operates through principal organs including the General Assembly, the Permanent Council, the Inter-American Council for Integral Development, the Inter-American Juridical Committee, the Inter-American Commission on Human Rights, and the General Secretariat, with its foundational principles enshrined in the Charter emphasizing nonintervention, sovereign equality, and the peaceful resolution of disputes.^[1]^[3] The OAS has advanced hemispheric integration through initiatives like the Inter-American Democratic Charter adopted in 2001, which provides a framework for defending democracy against threats such as coups or electoral fraud, and the American Convention on Human Rights, which established the binding Inter-American Court of Human Rights to adjudicate violations.^[1]^[4] It has mediated conflicts, monitored elections in countries including Venezuela and Nicaragua, and facilitated responses to security challenges like transnational crime and natural disasters, though its effectiveness has been constrained by funding dependencies—primarily from the United States, which contributes over half of the budget—and geopolitical divisions among members.^[3]^[1] Notable controversies include the 1962 suspension of Cuba following its alignment with communist regimes, which remains in effect despite periodic debates on reinstatement, and accusations of partisan interventions, such as U.S.-backed actions against leftist governments in the 20th century or disputed election audits in recent years that have strained relations with nations like Venezuela and Bolivia.^[3]^[4] These episodes highlight tensions between the OAS's democratic promotion mandate and perceptions of great-power influence, particularly from Washington, underscoring the organization's role as a contested arena for balancing multilateral ideals against national interests in the Western Hemisphere.^[3]^[5]

Organizations

Organization of American States

The Organization of American States (OAS) is a multilateral forum established to foster cooperation among the independent states of the Western Hemisphere on matters of democracy, human rights, security, and economic development. Its Charter, signed on April 30, 1948, in Bogotá, Colombia, by 21 nations, outlines goals including the maintenance of peace, promotion of representative democracy, and defense of sovereignty and territorial integrity.^[6] The OAS evolved from earlier Pan-American initiatives, such as the 1890 International Union of American Republics and the 1910 Pan American Union, which addressed hemispheric issues like arbitration and trade.^[5] Membership comprises 35 sovereign states from North, Central, and South America and the Caribbean, though Cuba's government has been excluded from participation since 1962 following its alignment with communist regimes, a suspension upheld by member consensus.^[7] The organization's structure centers on the General Assembly as its supreme authority, meeting annually to set policy; the Permanent Council, which handles ongoing diplomatic functions in Washington, D.C.; and the General Secretariat, led by a Secretary General elected for a five-year term by the Assembly.^[8] Specialized bodies include the Inter-American Commission on Human Rights, which monitors compliance with the American Convention on Human Rights, and the Inter-American Drug Abuse Control Commission.^[4] The OAS has invoked its Democratic Charter—adopted in 2001 to respond to threats against democratic order—on multiple occasions, such as suspending Honduras in 2009 after a military coup and condemning electoral irregularities in Venezuela in 2017 and Nicaragua in 2018.^[4] Funding primarily derives from assessed contributions by members, with the United States providing approximately 60% of the budget as of recent years, raising critiques from some quarters about disproportionate influence, though decisions require consensus among sovereign equals.^[4] In 2025, the 55th General Assembly, held June 25–27, addressed budget approvals and regional security, while newly inaugurated Secretary General Albert Ramdin prioritized democracy defense amid ongoing challenges like migration and transnational crime.^[9]^[4]

Organisation de l'armée secrète

The Organisation de l'Armée Secrète (OAS) was a clandestine paramilitary group formed by French military officers, Algerian settlers (pieds-noirs), and civilians opposed to Algerian independence from France during the Algerian War (1954–1962). Established in Madrid on February 11, 1961, by Pierre Lagaillarde, a former deputy who had participated in the 1960 Algiers barricades, and Jean-Jacques Susini, a medical student and activist, the OAS emerged in response to President Charles de Gaulle's negotiations with the Front de Libération Nationale (FLN), which the group viewed as a capitulation endangering French interests and European populations in Algeria.^[10] General Raoul Salan, a former commander-in-chief in Algeria who had joined the April 1961 generals' putsch, assumed leadership shortly thereafter, proclaiming himself supreme commander of the "national renewal" movement to preserve Algeria's status as French territory.^[11]^[12] The OAS's core ideology rejected decolonization, arguing that Algeria's integration into France—formalized by the 1958 constitution—made independence tantamount to abandonment, exposing settlers and loyal Muslims to FLN reprisals and regional communist expansion.^[13] Tracts distributed by the group framed the conflict as a defense against "betrayal" by the metropolitan government, calling for unity among Europeans and pro-French Algerians to counter FLN violence, which had already claimed thousands of lives through ambushes, bombings, and executions since 1954. The OAS positioned itself as the armed extension of French Algeria's will, drawing support from disaffected military elements who had fought in Indochina and resented the political shift under de Gaulle.^[14] From mid-1961, the OAS conducted a campaign of urban terrorism in Algeria and metropolitan France, targeting FLN sympathizers, pro-independence Muslims, journalists, and officials seen as facilitating withdrawal; actions included plastic bombings, drive-by shootings, and assassinations, with notable operations like the January 1962 execution of two Algiers OAS leaders by French authorities in retaliation.^[15] After the March 18, 1962, Évian Accords established a ceasefire and independence timeline, the OAS escalated with indiscriminate attacks to provoke FLN responses and derail the process, launching waves of bombings—such as 17 in Paris on January 18, 1962—and random killings that heightened communal tensions in Algiers.^[16]^[15] The group also plotted against de Gaulle, culminating in the August 22, 1962, Petit-Clamart ambush involving 187 shots fired at his Citroën, organized by OAS Delta commando under Jean-Marie Bastien-Thiry. These tactics, while militarily ineffective against French state forces, caused significant civilian disruption and deepened divisions, with OAS violence persisting alongside FLN reprisals until Algeria's independence.^[17] Salan's arrest on April 20, 1962, in Algiers fragmented the leadership, shifting operations to figures like Susini and prompting internal purges and defections.^[12] As French troops withdrew and settler exodus accelerated, the OAS's structure collapsed with the July 5, 1962, declaration of Algerian sovereignty, leading to its effective dissolution amid amnesties, trials, and exile for survivors; Salan received a life sentence in 1962 (commuted in 1968), while others like Susini faced imprisonment before release.^[18] The organization's failure underscored the limits of paramilitary resistance against state policy, though it reflected broader causal factors in the war, including FLN guerrilla successes, international pressure on France, and domestic political exhaustion after six years of conflict costing over 25,000 French lives.^[14]

Organization of Agreement States

The Organization of Agreement States (OAS) is a nonprofit, voluntary scientific and professional society incorporated in the District of Columbia, representing radiation control programs in U.S. states and territories that have entered into formal agreements with the Nuclear Regulatory Commission (NRC) under Section 274 of the Atomic Energy Act of 1954, as amended.^[19]^[20] These Agreement States—numbering 39 as of 2025—assume regulatory authority delegated by the NRC for licensing, inspection, and enforcement related to byproduct, source, and small quantities of special nuclear materials used in medicine, industry, and research, while the NRC retains oversight of larger facilities and higher-risk activities.^[21]^[22] The OAS facilitates coordination to ensure consistent, effective implementation of these programs as part of the national materials regulatory framework. The mission of the OAS is to promote cooperation and communication among Agreement States, the NRC, and states aspiring to Agreement status, thereby supporting uniform radiation safety standards and regulatory efficiency across jurisdictions.^[19] Its purpose includes providing a forum for Agreement States to collaborate on policy development, share best practices, and engage with federal regulators on rulemaking and compatibility requirements, which mandate that state regulations align with NRC standards to prevent fragmented oversight.^[21] Through working groups on topics such as medical uses, industrial radiography, and emergency response, the OAS addresses technical challenges, drafts comment letters on proposed NRC rules, and contributes to joint initiatives like the National Materials Program, which integrates state and federal efforts to regulate radioactive materials nationwide.^[23]^[19] Membership in the OAS consists of radiation control directors and staff from the 39 Agreement States, who implement their respective programs and participate in governance through a board of directors elected from member states.^[23] The organization holds annual meetings, such as the 2025 event scheduled for August 11–14 in Washington, D.C., themed around advancing regulatory partnerships, where members discuss emerging issues like enhanced security measures post-9/11 and updates to compatibility categories for state rules.^[19] These gatherings also include technical sessions, breakout discussions, and interactions with NRC leadership to resolve discrepancies in regulatory interpretations and improve program evaluations conducted under the Integrated Materials Performance Evaluation Program (IMPEP). By advocating for resource allocation and training, the OAS helps Agreement States maintain program adequacy amid evolving technologies and threats, such as those involving radioactive sources in dirty bomb scenarios.^[24]

Medicine and Biology

Oral Allergy Syndrome

Oral allergy syndrome (OAS), also known as pollen-food allergy syndrome (PFAS), is an IgE-mediated allergic reaction confined primarily to the oral mucosa, triggered by the ingestion of certain raw fruits, vegetables, nuts, or spices in individuals sensitized to pollen allergens.^[25]^[26] It arises from cross-reactivity between structurally similar proteins in pollen and those in plant-derived foods, leading to localized symptoms rather than systemic anaphylaxis in most cases.^[27]^[28] Unlike primary food allergies, OAS reactions typically resolve quickly upon removal of the offending food and pose low risk for severe outcomes, though rare progression to systemic symptoms has been documented.^[29]^[30] The pathophysiology involves sensitization to pollen aeroallergens, such as those from birch (Betula), grass, or ragweed, which share homologous epitopes with food proteins classified as pan-allergens, including pathogenesis-related proteins (PR-10 family, e.g., Bet v 1 in birch) and profilins.^[27]^[28] These food proteins are heat-labile and susceptible to enzymatic degradation in the gastrointestinal tract, explaining why symptoms are limited to the oral cavity where exposure occurs before denaturation; cooked or processed forms of the same foods rarely elicit reactions.^[26]^[31] Cross-reactivity patterns include birch pollen with pome fruits (apple, pear), stone fruits (peach, cherry), and vegetables (carrot, celery); grass pollen with tomato and legumes; and ragweed with melon and banana.^[27]^[28] Mast cell degranulation via IgE crosslinking in the oral mucosa releases histamine and other mediators, causing pruritus without deeper tissue involvement due to the transient nature of the allergens.^[29] Symptoms manifest within minutes of exposure as itching, tingling, burning, or edema of the lips, tongue, palate, throat, or gums, often described as a "scratchy" sensation.^[32]^[26] Rarely, symptoms may extend to the ears or eyes, but gastrointestinal or respiratory involvement is uncommon unless confounded by true food allergy.^[25] Symptoms are seasonal, peaking during pollen seasons due to boosted IgE levels, and affect pollen-allergic individuals disproportionately.^[28] Epidemiological data indicate OAS prevalence of 8.9% among children with allergic rhinitis or asthma, rising to 16.8% in adults with pollinosis, with overall rates in pollen-sensitized populations ranging from 10.8% to 24% depending on region and birch pollen exposure.^[33]^[34] Higher incidence occurs in temperate climates with prevalent birch sensitization, such as Northern Europe and North America, where up to 70% of birch-allergic patients report OAS symptoms.^[35]^[36] It is more frequently reported in adults than children, potentially due to cumulative pollen exposure, though underdiagnosis persists in non-specialist settings.^[37] Diagnosis relies on clinical history of pollen allergy combined with reproducible oral symptoms after raw plant food ingestion, supported by positive skin prick tests using fresh foods (prick-to-prick method) or serum-specific IgE to pollen and food extracts.^[26]^[27] Component-resolved diagnostics, measuring IgE to specific proteins like Pru p 1 (peach PR-10 homolog), enhance specificity by distinguishing cross-reactivity from primary allergies.^[28] Oral food challenges are rarely needed given the mild, localized nature but may confirm in ambiguous cases.^[38] Management centers on avoidance of implicated raw foods, with peeling skins or cooking (e.g., baking fruits) often sufficient to prevent reactions by altering proteins.^[32]^[31] Oral antihistamines provide symptomatic relief for acute episodes, while sublingual or subcutaneous immunotherapy for the underlying pollen allergy can desensitize and reduce OAS severity in up to 75% of birch-pollen cases.^[25]^[37] Epinephrine is not routinely required due to minimal anaphylaxis risk, but patients with history of systemic progression should carry it.^[30] No cure exists, but symptom control aligns with pollen avoidance strategies during high seasons.^[26]

Overall Survival

Overall survival (OS) refers to the length of time from a defined starting point, typically randomization in a clinical trial or initiation of treatment, until the date of death from any cause in patients with cancer.^[39] This endpoint captures the ultimate clinical outcome, encompassing both disease progression and potential treatment toxicities, and is considered the gold standard for evaluating therapeutic efficacy in oncology trials due to its objectivity and direct relevance to patient benefit.^[40] In randomized controlled trials, OS is calculated using Kaplan-Meier estimates, with patients alive at the time of analysis or lost to follow-up treated as censored data to account for incomplete observations.^[41] Median OS, the time at which half of the study participants have died, serves as a key summary statistic, providing a robust measure less influenced by outliers compared to mean survival.^[42] Regulatory agencies like the U.S. Food and Drug Administration (FDA) prioritize OS as a primary endpoint for drug approvals in advanced cancers, as it integrates safety and efficacy signals, including risks of long-term harms such as secondary malignancies or immune-related adverse events from immunotherapies.^[43] For instance, in trials halted early due to emerging toxicity data, OS enables detection of unfavorable risk-benefit profiles before full maturation of results.^[44] Unlike surrogate endpoints such as progression-free survival (PFS), which measures time to disease progression or death and can be assessed earlier, OS avoids biases from post-progression therapies that may confound PFS interpretations, though the two are not always correlated, particularly with targeted agents.^[45] PFS benefits do not reliably predict OS gains across therapy classes, underscoring OS's role as the definitive metric for confirming meaningful extensions in lifespan.^[46] Challenges in OS analysis include crossover designs allowing control-arm patients access to experimental treatments, which can dilute observed differences, and the need for long follow-up periods in curative settings.^[47] Recent FDA guidance emphasizes prospective planning for mature OS data collection, including sensitivity analyses for censoring assumptions and independent verification of vital status to enhance rigor.^[48]

2'-5'-Oligoadenylate Synthetase

2'-5'-Oligoadenylate synthetase (OAS) enzymes constitute a family of interferon-inducible proteins that detect double-stranded RNA (dsRNA), a hallmark of viral replication, and initiate an antiviral state within host cells.^[49] Upon binding dsRNA, OAS polymerizes ATP into 2'-5'-linked oligoadenylates (2-5A), short chains that serve as second messengers to activate ribonuclease L (RNase L).^[50] RNase L, in turn, cleaves single-stranded viral and cellular RNAs, halting protein synthesis and promoting apoptosis to limit viral spread.^[51] This pathway exemplifies a core mechanism of innate immunity, independent of adaptive responses, and is upregulated by type I interferons during infection.^[52] In humans, the functional OAS genes—OAS1, OAS2, and OAS3—are clustered on chromosome 12q24.2 and encode enzymes with varying numbers of catalytic domains: OAS1 possesses one domain (yielding 40-46 kDa isoforms), OAS2 has two (69-71 kDa), and OAS3 features three (approximately 100 kDa).^[53] ^[54] A related pseudogene, OASL, lacks synthetase activity but modulates other immune functions, such as RNA interference.^[55] Isoforms differ in dsRNA affinity and 2-5A production efficiency; for instance, OAS1 exhibits high specificity for short dsRNA stems, while OAS3 handles longer ligands.^[56] Genetic polymorphisms, particularly in OAS1, influence enzyme stability and antiviral efficacy, with certain variants (e.g., rs10774671) linked to reduced activity due to alternative splicing that excludes a membrane anchor.^[57] The activation mechanism involves conformational changes upon dsRNA binding, enabling the unusual 2'-5' phosphodiester linkages in 2-5A synthesis, distinct from the canonical 3'-5' bonds in cellular RNAs.^[58] Beyond RNase L-mediated RNA degradation, OAS1 contributes to translational repression via direct interference with initiation factors and safeguards interferon-beta production by countering viral suppressors.^[52] This dual role underscores OAS's integration into broader interferon-stimulated gene networks, amplifying defenses against RNA viruses such as flaviviruses and West Nile virus.^[59] OAS dysfunction or variation correlates with altered susceptibility to viral infections; for example, OAS1 polymorphisms associate with severe outcomes in diseases like West Nile virus encephalitis and hepatitis C, reflecting impaired RNase L pathway engagement.^[57] In tuberculosis, elevated OAS expression indicates interferon-driven responses, though causality remains under investigation.^[60] Experimental evidence from knockout models confirms OAS's necessity for controlling encephalomyocarditis virus replication, highlighting its non-redundant antiviral contributions.^[50]

Chemistry

O-Acetylserine

O-acetylserine (OAS), also known as O-acetyl-L-serine, is an α-amino acid derivative serving as a key intermediate in the biosynthesis of cysteine in bacteria and plants. Its chemical formula is C₅H₉NO₄, with a molecular weight of 147.13 g/mol.^[61] ^[62] The structure features an acetyl group esterified to the hydroxyl side chain of L-serine, specifically HO₂CCH(NH₂)CH₂OC(O)CH₃.^[61] Biosynthesis of OAS occurs via the acetylation of L-serine, catalyzed by serine acetyltransferase (SAT, EC 2.3.1.30), which transfers an acetyl group from acetyl-coenzyme A to the β-hydroxyl of serine.^[63] ^[64] This reaction activates serine for subsequent sulfhydrylation, preventing unproductive side reactions and facilitating cysteine formation. In plants, SAT isoforms localize to plastids, cytosol, and mitochondria, reflecting compartmentalized cysteine synthesis.^[65] OAS functions primarily as the substrate for O-acetylserine sulfhydrylase (OASS, also termed cysteine synthase, EC 2.5.1.47), which catalyzes the β-replacement of the acetoxy group with sulfide (HS⁻) to yield L-cysteine, acetate, and water.^[66] ^[67] This pyridoxal 5'-phosphate-dependent reaction represents the final step in the direct sulfhydrylation pathway of cysteine biosynthesis, essential for sulfur assimilation in organisms lacking alternative routes like mammals. Bacterial OASS exists as isoenzymes CysM and CysK, with CysK predominant under standard conditions; in plants, multiple OASS isoforms enable tissue-specific regulation.^[68] ^[69] Beyond catalysis, OAS exhibits regulatory roles in sulfur metabolism. It acts as a signal metabolite, accumulating under sulfur deficiency to induce S-responsive gene expression, including upregulation of sulfate transporters and enzymes in the assimilation pathway.^[70] OAS also inhibits SAT activity through feedback, forming a cysteine regulatory complex with OASS to balance flux toward cysteine production. Physical properties include a melting point of 143–144 °C (decomposition) and high water solubility (≥32 mg/mL), consistent with its polar structure.^[62] ^[71]

Computing and Technology

Office Automation Software

Office automation software encompasses computer-based applications designed to streamline administrative, clerical, and managerial tasks in organizational settings by digitizing processes such as document creation, data management, communication, and workflow routing.^[72] These systems emerged as a response to the inefficiencies of manual office operations, integrating hardware like personal computers with software to handle repetitive functions including text editing, numerical analysis, and electronic messaging.^[73] By the late 20th century, such software had become integral to reducing paper dependency and enhancing productivity through automation of routine data handling.^[74] The concept gained prominence in the 1970s and 1980s alongside the proliferation of desktop computing, with word processing applications marking the initial widespread adoption as they replaced typewriters for document drafting and revision.^[75] In 1977, Ricoh formalized the term "Office Automation" (OA) to describe integrated systems supporting office productivity, expanding in the 1980s to include networked tools for collaborative work.^[76] This era's evolution was driven by the shift from mainframe-based computing to affordable personal computers, enabling standalone and networked software that automated tasks like payroll processing and inventory tracking in business environments.^[72] Core components of office automation software include word processors for creating and formatting documents, spreadsheets for data calculation and analysis, and email clients for asynchronous communication.^[77] Examples encompass Microsoft Word, introduced in 1983 as Multi-Tool Word for the Xenix OS and later integrated into the Microsoft Office suite in 1989, which supports features like templates, spell-checking, and collaborative editing.^[78] Similarly, Microsoft Excel, launched in 1985 for Macintosh and 1987 for Windows, provides grid-based tools for formulas, charts, and pivot tables to manage financial and statistical data.^[79] Email software such as Microsoft Outlook, released in 1997, facilitates message composition, calendaring, and contact management, often bundled in productivity suites like Microsoft Office 365.^[80] Additional elements involve presentation software like Microsoft PowerPoint, debuted in 1987, for slide-based visual aids in reporting and database management systems for organizing structured information retrieval.^[79] Modern iterations incorporate workflow automation tools that define task sequences, approvals, and integrations across applications, as seen in platforms enabling real-time co-editing and cloud storage to further minimize manual intervention.^[81] These advancements have measurably increased operational efficiency, with studies indicating up to 30-50% time savings on administrative duties through digitized processes, though implementation requires user training to mitigate resistance to technological shifts.^[82]

Government Programs

Old Age Security

The Old Age Security (OAS) program is a non-contributory federal pension administered by Employment and Social Development Canada, providing monthly payments to eligible Canadian residents aged 65 and older as a foundational element of the country's retirement income system. Enacted through the Old Age Security Act in 1951, the program began delivering benefits in January 1952, initially offering a flat-rate pension financed from general government revenues rather than individual contributions. Unlike the contributory Canada Pension Plan, OAS aims to ensure a basic level of income security for seniors independent of prior employment history, though benefits are subject to income-tested clawbacks and supplemented by means-tested programs like the Guaranteed Income Supplement for lower-income recipients.^[83]^[84]^[85] Eligibility requires Canadian citizenship or legal residency status, attainment of age 65, and a minimum period of residence in Canada after age 18: at least 10 years for partial benefits if residing in Canada at application, or 20 years for payments received abroad, with full benefits prorated to 40 years of residency. Applications are typically automatic upon turning 64 for those receiving Canada Pension Plan benefits, but manual applications are required for others via Service Canada, with payments retroactive up to 11 months. Beneficiaries may defer receipt beyond age 65 for a 0.6% monthly actuarial increase (up to 36% at age 70), an option introduced in 2013 to encourage longer workforce participation amid rising life expectancies. Payments are taxable as income and adjusted quarterly based on the Consumer Price Index, with a recovery tax (clawback) reducing benefits by 15% of annual net world income exceeding $90,997 (2024 threshold, indexed annually).^[83]^[86]^[87] For the October to December 2025 quarter, the maximum monthly OAS pension stands at $727.67 for recipients aged 65–74, increasing to $800.44 for those 75 and older due to a 10% age-related supplement introduced in 2022; actual amounts are reduced for partial residency or clawed back based on income levels above specified thresholds (e.g., full clawback for singles with net income over approximately $148,451). In fiscal year 2017–2018, program expenditures reached $51 billion, reflecting its role as a universal base but raising concerns over fiscal sustainability given Canada's aging demographics, where the worker-to-retiree ratio is projected to decline, potentially straining general revenue funding without reforms.^[88]^[89]^[90] Critics, including policy analysts from the Fraser Institute, argue that OAS has deviated from its original poverty-alleviation intent by providing benefits to high-income seniors, advocating for means-testing or raising the eligibility age to 67 to align with longer lifespans and reduce intergenerational inequities, as the program's universality subsidizes affluent retirees at the expense of younger taxpayers. Proponents of expansion, such as the Bloc Québécois, have pushed for further increases for those under 75, though such proposals face opposition amid federal budget pressures and evidence that OAS alone covers only about 15–20% of average senior living costs, underscoring reliance on personal savings and contributory pensions. Empirical evaluations confirm high program uptake (over 95% of eligible seniors) but highlight administrative costs and the need for ongoing adjustments to prevent overpayments to deceased beneficiaries or non-residents.^[91]^[92]^[93]

Other Uses

Optical Absorption Spectrum

The optical absorption spectrum represents the variation in a material's absorption coefficient or absorbance as a function of wavelength or photon energy in the ultraviolet, visible, and near-infrared regions, primarily due to electronic transitions from valence to conduction bands in semiconductors or from ground to excited molecular orbitals in compounds. This spectrum provides insights into the electronic structure, revealing features such as bandgap energies, defect states, and vibrational fine structure. In solids like quantum wells, the absorption profile directly correlates with the joint density of states, exhibiting square-root-like edges near the bandgap for three-dimensional materials transitioning to step-like features in lower dimensions.^[94] Experimentally, the spectrum is measured using transmission spectrophotometry, where a broadband light source illuminates the sample, and the transmitted intensity is compared to a reference beam via detectors such as photodiodes or charge-coupled devices; absorbance follows the Beer-Lambert law, A(λ) = ε(λ) ⋅ c ⋅ l, with ε(λ) denoting wavelength-dependent molar absorptivity, c the analyte concentration, and l the optical path length. For nonequilibrium systems, such as laser-driven plasmas, absorption is quantified by the material's response to a probe beam, often requiring time-resolved setups to capture dynamic changes in electronic populations. Advanced computational methods, including ab initio density functional theory, simulate these spectra by calculating transition dipole moments and excitation energies, enabling predictions for complex systems without experimental data.^[95]^[96]^[97] Applications include quantitative chemical analysis via characteristic absorption peaks—for instance, identifying transition metal complexes or organic dyes—and biomedical diagnostics, such as photoacoustic imaging of myelinated nerves where spectra guide wavelength selection for optimal contrast based on hemoglobin and lipid absorptions peaking around 400–500 nm and 1200–1700 nm. In materials science, spectra assess optical properties of thin films or nanostructures, informing photovoltaic efficiency through bandgap determination, while environmental monitoring employs variants like differential optical absorption spectroscopy for trace gas detection in the atmosphere. Limitations arise from scattering in turbid media, necessitating inverse modeling to decouple absorption from scattering coefficients using radiative transfer equations.^[98]^[99]^[100]

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May 7, 2025 · Pollen food allergy syndrome (PFAS) primarily presents as oral allergy syndrome (OAS) with occasional systemic symptoms.<|separator|>
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Oral Allergy Syndrome | Symptoms & Treatment | ACAAI Public ...
Pollen Food Allergy Syndrome (PFAS), also known as oral allergy syndrome, is caused by cross-reacting allergens found in both pollen and raw fruits ...
[32]
Oral Allergy Syndrome (OAS): Symptoms & Treatment
OAS is a type of food allergy to vegetables, fruits and nuts. It causes an allergic reaction usually limited to your lips, mouth and throat.Overview · Symptoms And Causes · Management And TreatmentMissing: definition peer-
[33]
Prevalence of oral allergy syndrome in children with allergic diseases
Overall prevalence of OAS was 8.9% (95%CI 6.1-13.1%). Prevalence of OAS for allergic rhinitis and asthma were 8.8% and 9.1%, respectively.
[34]
Epidemiological study of oral allergy syndrome in birch pollen ...
Results: The prevalence of OAS was 10.8%. The rate of pollinosis complication in the OAS group was 67.4%, and OAS was observed in 16.8% of pollinosis patients.
[35]
Epidemiological study of oral allergy syndrome in birch pollen ...
The prevalence of OAS was 10.8%. The rate of pollinosis complication in the OAS group was 67.4%, and OAS was observed in 16.8% of pollinosis patients. Causative ...
[36]
Oral Allergy Syndrome in Birch Pollen-Sensitized Patients from a ...
Jul 3, 2018 · The incidence of OAS was 17.4% (n = 12) in males and 23.2% (n = 13) in females (P = 0.418). There was no significant difference between the ...
[37]
Pollen food allergy syndrome (PFAS): A review of current available ...
Jul 31, 2019 · Varying reports have been made of the prevalence of PFAS, ranging from 4.7% to greater than 20% in children and 13% to 58% in adults. Prevalence ...Missing: epidemiology | Show results with:epidemiology
[38]
Factors associated with the development of oral allergy syndrome
Oral allergy syndrome (OAS) is an IgE-mediated food allergy (FA) that mainly leads to oropharyngeal mucosal symptoms immediately after antigen intake. The ...Missing: treatment | Show results with:treatment
[39]
Clinical endpoints in oncology - a primer - PMC - NIH
Overall survival (OS) is defined as the time from randomization to death [10]. Any patients lost to follow up or still alive at the time of evaluation are ...
[40]
How is overall survival assessed in randomised clinical trials in ...
Nov 6, 2023 · OS was defined to be time from randomisation to death from any cause in 87 (89%) papers. Two papers (2%) defined the starting point to be ...
[41]
How is overall survival assessed in randomised clinical trials ... - NIH
Nov 6, 2023 · OS was defined to be time from randomisation to death from any cause in 87 (89%) papers. Two papers (2%) defined the starting point to be ...
[42]
What do clinical trial results mean | Cancer Research UK
Overall survival (OS). How long people live after they join a trial or start treatment ; Median overall survival. The time at which half of the people in the ...How Long People Live... · How Well Treatment Works... · Other Terms You May Hear<|separator|>
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[PDF] Approaches to Assessment of Overall Survival in Oncology Clinical ...
assessment of overall survival in oncology clinical trials. 105 ... well-defined if the trial was not prospectively designed to assess overall survival.
[44]
Overall survival assessment in cancer drug trials - The Lancet
Oct 16, 2025 · Overall survival helps to detect these signals of harm early, so that the trials can be stopped midway, as was the case with immunotherapy ...
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Relationship between Progression-free Survival and Overall ... - NIH
There does not appear to be a difference in the magnitude of OS versus PFS benefits among biologic/targeted therapies versus their comparators. However, ...
[46]
Irreconcilable Differences: The Divorce Between Response Rates ...
Mar 17, 2023 · Recent oncology trials have highlighted a lack of correlation between these early efficacy end points and overall survival (OS).
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Improving Collection and Analysis of Overall Survival Data - Available
OS is an important endpoint for both safety and efficacy and is a critical component of oncology drug development programs. Improved prospective planning, ...Abstract · Introduction · Trial Design and Planning... · Prespecified Statistical...
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AACR, ASA, and FDA Outline Considerations for Overall Survival ...
Jul 22, 2024 · OS measures how long a patient survives after treatment and is an important metric of a drug's efficacy and safety. It has long been considered ...
[49]
OAS1 - 2'-5'-oligoadenylate synthase 1 - UniProt
May 18, 2010 · Interferon-induced, dsRNA-activated antiviral enzyme which plays a critical role in cellular innate antiviral response.
[50]
Viral Encounters with 2′,5′-Oligoadenylate Synthetase and ...
Dec 1, 2007 · Therefore, 2-5A is an early transient-response molecule or alarmone that signals antiviral innate immunity through RNase L activation. RNase L ...
[51]
New insights into the role of RNase L in innate immunity - PubMed
The interferon (IFN)-inducible 2'-5'-oligoadenylate synthetase (OAS)/RNase L pathway blocks infections by some types of viruses through cleavage of viral ...
[52]
Oligoadenylate synthetase 1 displays dual antiviral mechanisms in ...
Feb 28, 2024 · Oligoadenylate synthetase 1 displays dual antiviral mechanisms in driving translational shutdown and protecting interferon production.
[53]
The human 2',5'-oligoadenylate synthetase locus is composed of ...
The human 2',5'-oligoadenylate synthetase locus is composed of three distinct genes clustered on chromosome 12q24.2 encoding the 100-, 69-, and 40-kDa forms.
[54]
The 2′-5′-Oligoadenylate Synthetase 3 Enzyme Potently ... - NIH
In humans, the OAS family consists of four members: OAS1, OAS2, OAS3, and OASL (12, 13). OAS1, OAS2, and OAS3 have 2′-5′-oligoadenylate synthetase activity ...
[55]
Oligoadenylate synthase-like (OASL) proteins: dual functions and ...
Mar 6, 2015 · Extracellular 2'-5' oligoadenylate synthetase stimulates RNase L-independent antiviral activity: a novel mechanism of virus-induced innate ...
[56]
novel RNA molecular signature for activation of 2′-5
Human 2′-5′ oligoadenylate synthetase-1 (OAS1) is central in innate immune system detection of cytoplasmic double-stranded RNA (dsRNA) and promotion of host ...Oas1 Expression And... · Results · Oas1 Activation Is Strongly...<|separator|>
[57]
Variation in Antiviral 2′,5′-Oligoadenylate Synthetase (2′5′AS ...
OAS genes encoding the antiviral enzyme 2′,5′-oligoadenylate synthetase (2′5′AS) are critical components of the innate immune response to viruses.
[58]
Crystal Structure of the 2′-Specific and Double-Stranded RNA ...
The 2′-5′-oligoadenylate synthetases are activated by viral double-stranded RNA in infected cells and initiate a cellular response by synthesizing 2′-5′- ...
[59]
Activation of 2′ 5′-Oligoadenylate Synthetase by Stem Loops at ...
Several lines of evidence suggest that OAS enzymes play a key role in the IFN response to WNV infection. The importance of OAS enzymes in the antiviral response ...
[60]
OAS1, 2, and 3: Significance During Active Tuberculosis?
The 2'-5'-oligoadenylate synthetases (OAS), namely OAS1, OAS2 and OAS3 are part of the interferon-induced genes which until now have been synonymous with an ...
[61]
O-Acetyl-L-serine | C5H9NO4 | CID 99478 - PubChem
O-acetyl-L-serine is an acetyl-L-serine where the acetyl group is attached to the side-chain oxygen. It is an intermediate in the biosynthesis of the amino ...
[62]
O-acetylserine | 4985-36-8 - ChemicalBook
Jul 14, 2023 · Molecular Formula: C5H9NO4. Molecular Weight: 147.13. MDL Number ... O-acetylserine Properties. Melting point, 143-144 °C (decomp). Boiling ...
[63]
Structure and Mechanism of O-Acetylserine Sulfhydrylase
1). The amino acid precursor of l-cysteine is l-serine, which undergoes a substitution of its β-hydroxyl with a thiol in two steps. Serine acetyltransferase (EC ...
[64]
Metabolism and Regulatory Functions of O-Acetylserine, S ...
In bacteria and plants, Cys is synthesized from OAS, which is an activated Ser, by incorporating sulfide into the direct sulfhydrylation pathway (Figure 2 for ...
[65]
Analysis of the Arabidopsis O-Acetylserine(thiol)lyase Gene Family ...
Cys synthesis in plants takes place in plastids, cytosol, and mitochondria. Why Cys synthesis is required in all compartments with autonomous protein ...
[66]
Structure of the O-Acetylserine Sulfhydrylase Isoenzyme CysM from ...
The enzyme O-acetylserine sulfhydrylase participates in the biosynthesis of l-cysteine in bacteria and plants. The structure of isoenzyme B (CysM) from ...
[67]
Molecular Basis of Cysteine Biosynthesis in Plants
O-Acetylserine sulfhydrylase (OASS) catalyzes the final step of cysteine biosynthesis, the pyridoxal 5′-phosphate (PLP)-dependent conversion of O ...
[68]
Mechanism of the Addition Half of the O-Acetylserine Sulfhydrylase ...
O-Acetylserine sulfhydrylase (OASS) catalyzes the last step in the cysteine biosynthetic pathway in enteric bacteria and plants, substitution of the β-acetoxy ...
[69]
O-acetylserine (thiol) lyase: an enigmatic enzyme of plant cysteine ...
O-acetylserine (thiol) lyase (OAS-TL) catalyses the reaction of inorganic sulphide with O-acetylserine (OAS).O-Acetylserine (thiol) Lyase... · Analysis Of Sulphur... · Results
[70]
Metabolism and Regulatory Functions of O-Acetylserine, S ...
Briefly, OAS has a signal function to regulate S-responsive gene expression. OAS also regulates Cys biosynthesis at enzymatic level. OAS and N-Acetylserine ...
[71]
Structural Basis for Interaction of O-Acetylserine Sulfhydrylase and ...
These structures indicate that O-acetylserine and the C terminus of At-SAT compete for the same binding site and explain how OASS activity is downregulated upon ...
[72]
Office Automation - Inc. Magazine
Feb 6, 2020 · Office automation refers to the integration of office functions usually related to managing information.
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Office Automation - an overview | ScienceDirect Topics
Office automation refers to the use of technology to facilitate information handling tasks in various office environments, accommodating a diverse range of ...Applications · Documents · I Computer Use<|separator|>
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Office automation: Definition, benefits, and implementation - Workato
Office automation refers to the integration of electronic equipment, computer software, and systems used to digitize repetitive day-to-day data collection, ...
[75]
[PDF] Office automation: a look beyond word processing - Calhoun
Word processing was the first of various forms of office automation technologies to gain widespread acceptance and usability in the business world.
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Coining Office Automation acronym | Company History | About Ricoh
In 1977, we coined the acronym Office Automation, for office automation. During the 1980s, we extended our office productivity support by rolling out a lineup ...Missing: evolution | Show results with:evolution
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https://www.lenovo.com/ca/en/glossary/oa/
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What is a Word Processor? - Microsoft
A word processor is a software or program that allows users to create. edit. and save documents. Learn more about the capabilities of word processing ...
[79]
What is office automation software? A complete guide - Lark
Sep 17, 2025 · Office automation software refers to technology used to digitize, streamline, and automate routine office tasks. It includes tools for ...What Are The Benefits Of... · How Lark Enables True Office... · Automating Administrative...
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Key Applications in Microsoft Office Suite | QCT College
May 27, 2024 · Key Applications in Microsoft Office Suite · Microsoft Word: · Microsoft Excel: · Microsoft PowerPoint: · Microsoft Outlook: · Microsoft OneNote:
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5 Must-Haves for Office Workflow Automation - Complete Guide
Rating 4.3 (533) · Free · Business/ProductivitySep 23, 2025 · Core components of office automation: · Workflow automation: Digital routing of tasks, approvals, and information through predefined processes.
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What is Office Automation? Your Complete Guide - Solvexia
Jun 5, 2024 · Office automation is a general term that describes the different types of computer systems and software that are used to collect digitally, store, transfer, ...
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Old Age Security - Canada.ca
Sep 26, 2025 · Old Age Security (OAS) provides monthly payments to seniors who are 65 years or older, are or were Canadian citizens or legal residents, ...Apply, delay, or change your ...How much you could receiveDo you qualifyOAS Payment AmountsWhile receiving OAS
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[PDF] Canada's Old-Age Security Program: First Decade of Operations
CANADA'S income-maintenance programs for the aged that are now in effect first became operative in 1952. The programs' ha.ve the same dual ap-.
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Old Age Security Act ( RSC , 1985, c. O-9) - Laws.justice.gc.ca
Old Age Security Act ( R.S.C. , 1985, c. O-9) · Table of Contents · Related Information · Amendments * · Regulations made under this Act · Section menu · About this ...
[86]
Canada's Retirement Income System - Library of Parliament
2.1 Old Age Security Program. The OAS pension is a monthly payment available to most Canadians who are 65 years of age and over and meet the status and ...<|separator|>
[87]
Old Age Security: How much you could receive - Canada.ca
Old Age Security (OAS) pension amounts – October to December 2025. Age, Maximum monthly payment amount, To receive the OAS your annual net world income in ...Maximum payments and... · Your payment
[88]
Old Age Security payment amounts - Benefits - Canada.ca
Maximum payments and income thresholds - October to December 2025 ; I am single, widowed or divorced, less than $22,440, up to $1,105.43 ; I have a spouse/common- ...Table of Benefit Amounts by... · Old Age Security Benefits
[89]
How much will your OAS payments be? - Qtrade
As you can see from the chart below, the 2025 maximum monthly amount paid by OAS is $727.67 for people between the age of 65 and 74, which comes out to $8,732. ...
[90]
Evaluation of the Old Age Security program: Phase 2 - Canada.ca
The Old Age Security (OAS) program is the first pillar of Canada's retirement income system. Program costs amounted to $51 billion in fiscal year 2017 to 2018, ...List of tables · Introduction · Deferral of the Old Age... · Annex 1: Old Age Security...Missing: criticisms | Show results with:criticisms
[91]
Federal government should reject Bloc plan—and raise OAS age of ...
Oct 21, 2024 · The House of Commons passed a private member's bill by the Bloc Quebecois to increase Old Age Security (OAS) payments for younger seniors (aged 65-74) by 10 ...
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https://nationalpost.com/news/canada/liberals-urged-to-cut-old-age-security-spending-in-upcoming-budget
[93]
Will CPP and Old Age Security last as Canada's senior population ...
Sep 29, 2025 · CPP and OAS alone will fall short of funding retirement for most Canadians who will need to save on their own. Even if they are entitled to the ...
[94]
[PDF] Optical Physics of Quantum Wells - Stanford Electrical Engineering
The optical absorption spectrum therefore has a form that follows directly from the density of states in energy, and in bulk (3D) semiconductors the result ...
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[PDF] Optical absorption properties of laser-driven matter
Dec 12, 2018 · To define the optical absorption for. nonequilibrium matter, we quantify its response to interaction. with a monochromatic probe light at a ...
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[PDF] Ab initio calculations of optical absorption spectra
We describe an ab initio approach to compute the optical absorption spectra of molecules and solids, which is suitable for the study of large systems and ...
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[PDF] Absorption Spectrophotometry
Absorption spectrophotometry in many ways offers a means of analysis which supplements the information obtainable by emission spectroscopy and allows.
[98]
Optical absorption spectra and corresponding in vivo photoacoustic ...
Sep 4, 2023 · This paper presents the first known characterization of the optical absorbance spectra of fresh myelinated nerve samples using a wide spectrum ...
[99]
Tutorial on methods for estimation of optical absorption and ... - NIH
Jun 11, 2024 · This tutorial aims to help readers understand the process of extracting optical absorption and scattering properties from a given sample by solving the inverse ...
[100]
[PDF] Absorption methods - IS MUNI
• resonant optical absorption spectroscopy (ROAS), also known as atomic absorption spectroscopy. (AAS) —or optical absorption spectroscopy—OAS. • represents ...