TMP
TMP Worldwide Inc. is a multinational advertising and talent acquisition firm specializing in employer branding, recruitment advertising, and digital talent marketing solutions.[1] Founded in 1967 by Andrew J. McKelvey as Telephone Marketing Programs, the company initially focused on Yellow Pages directory advertising, growing to become the world's largest agency in that sector by the 1980s with gross billings exceeding $35 million.[1][2] Expanding into human resources, TMP entered the recruitment advertising market in 1993 through acquisitions and went public in 1996, raising $80.5 million while integrating over 36 companies in subsequent years.[1] Its most notable achievement was the development and promotion of Monster.com, an pioneering online job board that by 1999 listed over 204,000 job openings and managed 1.3 million resumes, contributing to TMP's reported sales of $406.8 million in 1998 and establishing it as the 14th largest advertising agency worldwide.[1] Under McKelvey's leadership as president and chairman, who retained significant ownership stakes, the firm emphasized data-driven strategies and global expansion, operating offices across multiple cities.[1] Despite its successes, TMP faced challenges including legal disputes over domain names and trade secrets, as well as involvement in the 2006 stock options backdating scandal through its Monster subsidiary, which eroded investor confidence.[3][4] Additionally, a 2010 voluntary administration in its Australian operations surprised the industry amid broader economic pressures, though the core U.S.-based entity persisted by pivoting to digital technologies powered by vast user data from platforms like TalentBrew.[5] Today, TMP continues as a technology-driven provider of personalized recruitment communications, leveraging proprietary intelligence from nearly 400 million user sessions to deliver measurable employer branding outcomes.[6]Biology and medicine
Trimethoprim
Trimethoprim is a synthetic bacteriostatic antibiotic that selectively inhibits bacterial dihydrofolate reductase (DHFR), the enzyme responsible for reducing dihydrofolate to tetrahydrofolate, a critical cofactor for thymidylate and purine synthesis in bacterial DNA and RNA production.[7] This mechanism disrupts folic acid metabolism in susceptible pathogens, particularly gram-negative bacteria like Escherichia coli, while mammalian cells remain largely unaffected due to higher DHFR affinity for the drug in humans.[8] By accumulating dihydrofolate and depleting tetrahydrofolate, trimethoprim halts bacterial proliferation without directly impacting host folate pathways.[9] Clinically, trimethoprim is indicated for treating uncomplicated urinary tract infections (UTIs) caused by susceptible Enterobacteriaceae, with oral doses of 100-200 mg twice daily achieving cure rates of 80-90% in short-term therapy based on randomized controlled trials.[10] It is also used for prophylaxis against UTIs in recurrent cases and for preventing Pneumocystis jirovecii pneumonia in immunocompromised individuals, such as those with HIV, at low doses of 160 mg daily.[11] Empirical data from pediatric trials show long-term low-dose trimethoprim-sulfamethoxazole reduces UTI incidence by up to 85% compared to placebo in predisposed children, though monotherapy carries risks of adverse effects like hyperkalemia.[12][13] Trimethoprim is most commonly administered in fixed combination with sulfamethoxazole (co-trimoxazole or Bactrim), which blocks dihydropteroate synthase upstream in the folate pathway, yielding synergistic bactericidal effects against a broader spectrum including some gram-positive organisms.[10] This pairing enhances efficacy against resistant strains by sequential blockade, as validated in clinical studies for acute exacerbations of chronic bronchitis and traveler's diarrhea.[14] Global surveillance data indicate rising resistance, with E. coli trimethoprim resistance exceeding 20-30% in many regions per WHO GLASS reports, driven by plasmid-encoded variant DHFR enzymes, necessitating susceptibility testing prior to use.[15][16]Thymidine monophosphate
Thymidine monophosphate, also known as deoxythymidine monophosphate (dTMP) or deoxythymidylic acid, is a pyrimidine nucleotide composed of the base thymine linked to a deoxyribose sugar via a β-N1-glycosidic bond, with a phosphate group esterified at the 5' position of the sugar.[17] This structure positions dTMP as a key precursor in the deoxyribonucleotide pool essential for DNA biosynthesis, distinct from the ribonucleotide uridine monophosphate (UMP) found in RNA due to the deoxyribose and thymine (5-methyluracil) components.[18] Biosynthesis of dTMP primarily occurs through the de novo pathway, where thymidylate synthase catalyzes the reductive methylation of deoxyuridine monophosphate (dUMP) to dTMP, utilizing 5,10-methylenetetrahydrofolate as the methyl donor and requiring dihydrofolate reductase for cofactor regeneration.[19] Salvage pathways supplement this by phosphorylating free thymidine to dTMP via thymidine kinase, which adds the initial phosphate group.[20] Subsequent phosphorylation by thymidylate kinase converts dTMP to dTDP, and nucleoside diphosphate kinase further yields dTTP, the direct substrate for DNA polymerases.[19] This sequential activation ensures balanced dNTP pools, as dTMP imbalances can stall replication forks and trigger apoptosis.[21] In DNA replication and repair, dTTP derived from dTMP serves as one of four canonical building blocks incorporated by DNA polymerase opposite adenine residues, enabling accurate semi-conservative duplication during the S phase and base excision repair.[18] Deficiencies in dTMP synthesis, such as those from thymidylate synthase inhibition or folate depletion, lead to uracil misincorporation into DNA, elevating mutation rates and genomic instability.[21] Thymidine phosphorylase deficiency, caused by TYMP gene mutations, disrupts salvage by accumulating unmetabolized thymidine, which competitively inhibits mitochondrial dNTP synthesis and depletes mtDNA, manifesting in mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), an autosomal recessive disorder with onset typically in adolescence featuring leukoencephalopathy, ptosis, and gastrointestinal dysmotility.[22][23] Molecular biology applications leverage dTMP pathways for probing nucleotide dynamics; for instance, radiolabeled thymidine incorporates via salvage to track S-phase progression, while dTMP analogs inform enzyme kinetics in replication studies, though direct dTMP use is limited compared to triphosphates in techniques like PCR, where dTTP analogs enable fork progression assays.[24] These roles underscore dTMP's indispensability in maintaining genomic fidelity, with disruptions linked to oncogenesis via thymidylate stress.[21]Chemistry
Trimethylolpropane
Trimethylolpropane (TMP), also known as 2-ethyl-2-(hydroxymethyl)propane-1,3-diol, is a branched-chain organic triol with the molecular formula C₆H₁₄O₃ or structural formula CH₃CH₂C(CH₂OH)₃.[25] This colorless to white crystalline solid has a melting point of 56–58 °C and is sparingly soluble in water but highly soluble in organic solvents such as alcohols and ethers.[25] Industrial production of TMP involves the base-catalyzed aldol condensation of n-butyraldehyde with excess formaldehyde to form 2,2-dimethylolbutyraldehyde, followed by a Cannizzaro disproportionation reaction under alkaline conditions to yield TMP and formate byproducts; alternatively, the intermediate can be hydrogenated.[26] The process typically uses sodium hydroxide as catalyst, with formaldehyde provided as aqueous formalin solution, and requires subsequent purification steps including distillation to remove impurities like di-trimethylolpropane.[27] This method has been the standard since mid-20th-century commercialization, enabling high-yield synthesis for large-scale applications.[28] TMP functions primarily as a polyfunctional alcohol in polymer chemistry, serving as a cross-linking agent and building block for alkyd resins in surface coatings and paints, where it enhances durability and gloss.[29] It is also incorporated into polyurethane foams, elastomers, and adhesives for improved mechanical strength and flexibility, and esterified to produce high-performance synthetic lubricants with superior thermal stability and viscosity index for automotive and industrial uses.[30] Additional applications include plasticizers, printing inks, and radiation-curable resins. The global TMP market reached a value of USD 655 million in 2024, reflecting its essential role in these sectors amid growing demand for advanced materials.[31] Toxicological data indicate low acute toxicity for TMP, with rat oral LD₅₀ values exceeding 5,000 mg/kg and dermal LD₅₀ > 2,000 mg/kg, classifying it as practically non-toxic via ingestion or skin contact in single exposures.[32] However, it acts as a skin, eye, and respiratory irritant, potentially causing redness, pain, or dermatitis upon prolonged contact or inhalation of dust.[33] Aquatic toxicity is moderate, with LC₅₀ values for fish around 100–1,000 mg/L, though it is not readily biodegradable and persists in sediments.[34] Animal studies suggest possible reproductive hazards, including reduced fertility at high doses (>500 mg/kg/day), warranting precautions in occupational handling.[35] Safety data sheets from manufacturers recommend personal protective equipment and ventilation to mitigate risks.[36]2,2,4-Trimethylpentane
2,2,4-Trimethylpentane, also known as isooctane, is a branched-chain saturated hydrocarbon with the molecular formula C₈H₁₈ and structure (CH₃)₃CCH₂CH(CH₃)₂.[37][38] As an isomer of n-octane, its highly branched configuration provides exceptional resistance to autoignition, making it a key reference in petroleum chemistry for evaluating fuel performance.[39] In the mid-1920s, systematic engine testing by Graham Edgar at Ethyl Corporation identified 2,2,4-trimethylpentane among C₈ hydrocarbons as exhibiting the highest knock resistance, with no detonation under compression ratios that induced knocking in straight-chain variants.[40] This led to its designation as the 100 reference standard in the octane rating scale, formalized by ASTM methods around 1929, where fuels are compared to blends of this compound and n-heptane (rated 0) in cooperative fuel research engines operating at standardized conditions of 600 rpm, variable compression, and controlled intake temperatures.[41] The scale quantifies a fuel's ability to withstand pre-ignition without abnormal combustion, directly linking molecular branching to delayed radical chain propagation during the induction period.[42] Commercially, 2,2,4-trimethylpentane is produced through the acid-catalyzed oligomerization of isobutylene to diisobutene intermediates, followed by selective hydrogenation over catalysts like nickel or palladium, yielding high-purity product suitable for fuel blending.[43] It serves as a component in high-performance gasoline (typically 5-10% by volume) and aviation fuels like 100LL avgas, enhancing detonation margins in high-compression piston engines, and as a non-polar solvent in laboratory extractions and spectrophotometric analyses due to its low reactivity and boiling point of 99.2°C.[44][45] Combustion data from rapid compression machines and detailed kinetic simulations confirm its research octane number of 100, with ignition delays exceeding those of n-heptane by factors of 10-20 at 800-1000 K and equivalence ratios near 1, attributable to stable tertiary carbon sites suppressing low-temperature oxidation pathways.[46][47]Computing
/tmp directory
The/tmp directory serves as a standard location in Unix-like operating systems for storing temporary files generated by applications during runtime, such as intermediate data, caches, or scratch space required for processing tasks. These files are intended to be short-lived, with programs expected to remove them upon completion to prevent accumulation and resource exhaustion. The directory's design accommodates multi-user environments by being world-writable, typically with permissions set to drwxrwxrwt (mode 1777), where the trailing 't' indicates the sticky bit, which restricts users to deleting or renaming only their own files despite the broad write access.[48][49]
This convention originated in early Unix systems and was formalized in POSIX standards, with /tmp explicitly retained in POSIX.1-2008 and subsequent revisions like POSIX.1-2017 to support legacy applications assuming its availability, though implementations are encouraged to mount it on volatile filesystems like tmpfs for automatic clearance on reboot.[48] Environment variables such as TMPDIR allow overriding the default path for temporary files, prioritizing user-specified directories over /tmp as per POSIX guidelines.[50]
Security vulnerabilities arise from /tmp's world-writable nature, enabling attacks such as symlink races where a malicious user creates symbolic links to sensitive files, potentially allowing privilege escalation or data leakage when another process writes to the directory. Historical exploits have leveraged this to hijack temporary files by overwriting or predicting names, with tools like TmpWatcher developed to detect such misuse in development pipelines. To mitigate risks, best practices include using unique, unpredictable filenames (e.g., via mktemp), private directories, or O_EXCL flags for creation, and mounting /tmp on a separate partition to limit denial-of-service impacts from unchecked growth.[49][51][52]
Cleanup is handled variably across distributions: older systems like RHEL 6 used cron jobs with tmpwatch to remove files unaccessed for 10 days, while modern ones employ systemd-tmpfiles for periodic purging—executed daily via a timer unit, deleting /tmp contents older than 10 days by default, configurable through /etc/tmpfiles.d/tmp.conf. On systems using tmpfs, files vanish on reboot or power loss, reducing persistence but increasing reliance on RAM/swap. In server environments, logs from tools like lsof often reveal rapid turnover, with /tmp filling from concurrent processes (e.g., uploads or computations) if cleanup lags, necessitating monitoring to avoid outages.[53][54][55]