Advances in solid phase microextraction for the analysis of volatile compounds in explosives, tire treatments, and entomological specimens

Solid phase microextraction is a powerful and versatile technique, well-suited to the analysis of numerous samples of forensic interest. The exceptional sensitivity of the SPME platform, combined with its adaptability to traditional GC-MS systems and its ability to extract samples with minimal work-up, make it appropriate to applications in forensic laboratories. In a series of research projects, solid phase microextraction was employed for the analysis of explosives, commercial tire treatments, and entomological specimens. In the first project, the volatile organic compounds emanating from two brands of pseudo-explosive training aids for use in detector dog imprinting were determined by SPME-GC-MS, and the efficacy of these training materials was tested in live canine trials. In the second project, the headspace above various plasticizers was analyzed comparative to that of Composition C-4 in order to draw conclusions about the odor compound, 2-ethyl-1-hexanol, with an eye toward the design of future training aids. In the third, automobile tires which had participated in professional race events were analyzed for the presence of illicit tire treatments, and in the fourth, a novel SPME-GC-MS method was developed for the analysis of blowfly (Diptera) liquid extracts. In the fifth and final project, the new method was put to the task of performing a chemotaxonomic analysis on pupa specimens, seeking to chemically characterize them according to their age, generation, and species

Irrigation-Yield Production Functions and Irrigation Water Use Effciency Response of Drought-Tolerant and Non-Drought-Tolerant Maize Hybrids under Different Irrigation Levels, Population Densities, and Environments

Irrigation-yield production functions (IYPFs), irrigation water use effciency (IWUE), and grain production per unit of applied irrigation of non-drought-tolerant (NDT) and drought-tolerant (DT) maize (Zea mays L.) hybrids were quantified in four locations with different climates in Nebraska [Concord (sub-humid), Clay Center (transition zone between sub-humid and semi-arid); North Platte (semi-arid); and, Scottsbluff (semi-arid)] during three growing seasons (2010, 2011, and 2012) at three irrigation levels (fully-irrigated treatment (FIT), early cut-off (ECOT), and rainfed (RFT)) under two plant population densities (PPDs) (low-PPD; 59,300 plants ha-1; and, high-PPD, 84,000 plants ha-1). Overall, DT hybrids’ performance was superior to NDT hybrid at RFT, ECT, and FIT conditions, as confirmed by the yield response, IYPF and IWUE when all locations, years, and PPDs were averaged. The yield response to water was greater with the high-PPD than the low-PPD in most cases. The magnitude of the highest yields for DT hybrids ranged from 7.3 (low-PPD) to 8.5% (high-PPD) under RFT, 3.7 (low-PPD) to 9.6% (high-PPD) under ECOT, and 3.9% (high-PPD) under FIT higher than NDT hybrid. Relatively, DT hybrids can resist drought-stress conditions longer than NDT hybrid with fewer penalties in yield reduction and maintain comparable or even higher yield production at non-stress-water conditions

T Cells Use Rafts for Survival

T cell homeostasis must be tightly controlled. In this issue of Immunity, Cho et al. (2010) describe results that begin to define the roles of the T cell receptor, self-peptide-MHC ligands, cytokines, and membrane rafts in this dynamic process

AGA practitioner challenges: A mixed‐methods pilot survey

Background Androgenetic alopecia (AGA) practitioner care may be hampered by commercial biases and hair loss' omission from most medical curricula. Aim and Method Between November 2020 and September 2021, 34 AGA professionals (86% British; 62% trichologists), participated in a pilot, mixed-methods, survey. Practitioner views on: 1a–1j) AGA's commercial influences (e.g., participants were quantitatively assessed on their understanding of a popular, commercially-funded, AGA study) and 2a–2h) constraints on evidenced-based AGA responding (e.g., ethical dilemmas) were assessed. Quantitative responses are reported descriptively whilst qualitative responses are categorized alongside illustrative quotes. Results On average, (1a–1d) 42% of participants were misled by the popular AGA study and (1e) participants underestimated the extent of commercial biases in AGA research as 25%; (2a–2e). Participants also indicated that AGA treatment limitations and misinformation ethically challenged them (e.g., “[It's difficult to know when] to treat or not without being able to confirm the outcome”). (2c) Most (77%) indicated society played a powerful role in exacerbating AGA distress (e.g., “Society is hyper critical of appearance”) and 30% indicated greater “treatment” accessibility was needed: (e.g., “hair loss product [should] give clear indication of what the active ingredients are and how effective they are”). Conclusions Despite the limited sample size, these finding cohere with previous identified challenges of the AGA practitioner role. Evidence based guidance and research scrutiny tools would help practitioners overcome such challenges

EC00-2540 Field Records for Restricted Use Pesticide Applications and Integrated Crop Management by Private Applicators

Private applicators must record their restricted use pesticide (RUP) applications, as required by the Food, Agriculture, Conservation and Trade (FACT) Act of 1990. The USDA Agricultural Marketing Service administers this activity. In Nebraska, RUP application records must be maintained for three years from the date of application. The certified pesticide applicator should retain these RUP records, but must be able to make them accessible for copying by authorized representatives. This booklet is a suggested guide for preliminary or final RUP application records

Compilation of extended recursion in call-by-value functional languages

This paper formalizes and proves correct a compilation scheme for mutually-recursive definitions in call-by-value functional languages. This scheme supports a wider range of recursive definitions than previous methods. We formalize our technique as a translation scheme to a lambda-calculus featuring in-place update of memory blocks, and prove the translation to be correct.Comment: 62 pages, uses pi