Antioxidant-associated color problems in vinyl foams

Investigations of chemically-blown vinyl foam systems, based on electrical grade plasticizers, have shown that the inclusion of 2,2′-bis (4-hydroxyphenyl) propane (BPA) as an antioxidant results in color formation in the finished foam. Color formation appears to be due to interactions between BPA and the azodicarbonamide blowing agent. Metal ion(s) present in vinyl stabilizer/kickers are also shown to have an effect on color hue though not on color development per se. Mechanisms for the development of quinoidal and diazo color bodies, based on the reaction of BPA and azodicarbonamide are postulated. Based on these reaction mechanisms, it is shown that it is possible to choose an antioxidant that will not interact with azodicarbonamide. A rudimentary screening procedure is described for evaluating these systems.     

Physicians and sex therapy

The physician's role in sex therapy is discussed. Problems of sexual dysfunction and guidelines for physicians who wish to engage in sex therapy are set out briefly.     

Brain T2 relaxation times correlate with regional cerebral blood volume

We previously reported cerebellar and putaminal transverse relaxation time (T2) differences in children with ADHD and in adults with childhood trauma. As brain T2 can be altered by deoxyhemoglobin concentration ([dHb]) and because [dHb] is proportional to regional cerebral blood volume (rCBV), at steady state we attributed those differences to rCBV changes. Studies in other species have established a correlation between T2 and rCBV; however this has yet to be demonstrated in human brain. Echo planar imaging (EPI) T2 relaxometry and dynamic susceptibility-contrast (DSC) MRI were used to measure T2 and rCBV in 11 healthy adults. Significant T2-rCBV correlations were observed in both cerebellar vermis and putamen (r=0.759,p=0.007;r=0.782,p=0.004, respectively). These correlations predict 9±3% and 10±3% rCBV changes, respectively, for each 1-msec change in T2. Consequently, brain T2 measurements may be useful for estimating steady-state rCBV.     

The effect of blending resins on plastisol performance

Blending resins are well known by plastisol compounders as an economical substitute for PVC dispersion resin and as viscosity modifier. As dispersion resin supply tightens, interest grows in blending resins and how to choose the one that best fits the compounder's specifications. Eleven representative blending resins have been characterized, compounded into plastisols and screened for performance. A regression analysis and resulting contour plots have supplied a means of correlating resin molecular weight, particle size and surface area with plastisol, gel/fusion, and physical properties. The trends described in the contour plots allow the prediction of the best blending resin criteria for a specific application.     

Build community before the storm: The National Weather Service's social media engagement

The current study examines crisis communication on social media by observing how twelve National Weather Service (NWS) offices use Twitter to facilitate engagement with stakeholders during threat and nonthreat periods. Using content analytic methods, we examine message features related to content and structure during a 3‐month period in spring 2016. We conduct chi‐square analyses to determine how the prevalence of these features varies by time. Results indicate that NWS offices use Twitter for ongoing engagement communication through both the content and structure of their messages, where community building and action‐orientated messages are primarily used during nonthreat periods. When fair weather changes and storms approach, the offices shift to the communication of risk. Our findings underscore the need to examine organizational communication practices in a manner that recognizes the distinctions between long‐term engagement goals and short‐term goals related to the mission of the organization.     

On-chip, time-correlated, fluorescence lifetime extraction algorithms and error analysis

A new, simple, and hardware-only fluorescence-lifetime-imaging microscopy (FLIM) is proposed to implement on-chip lifetime extractions, and their signal-to-noise-ratio based on statistics theory is also deduced. The results are compared with Monte Carlo simulations, giving good agreement. Compared with the commonly used iterative least-squares method or the maximum-likelihood-estimation- (MLE-) based, general purpose FLIM analysis software, our algorithm offers direct calculation of fluorescence lifetime based on the collected photon counts stored in on-chip counters and therefore delivers faster analysis for real-time applications, such as clinical diagnosis. Error analysis considering timing jitter based on statistics theory is carried out for the proposed algorithms and is also compared with MLE to obtain optimized channel width or measurement window and bit resolution of the time-to-digital converters for a given accuracy. A multi-exponential, pipelined fluorescence lifetime method based on the proposed algorithms is also introduced. The performance of the proposed methods has been tested on mono-exponential and four-exponential decay experimental data.     

An assessment of on-line engineering design problem presentationstrategies

This paper describes the assessment of three on-line learning modules in engineering design for first-year students developed at Columbia University. The assessment includes results from more than 200 students who used test and control versions of each module during the 1996-1997 academic year. The goal of the assessment was to identify presentation formats and strategies for on-line engineering design problems that improved student performance on the design problem or on a short paper and pencil follow-up quiz taken immediately after module use. Students nearly unanimously preferred modules that incorporated animation and interactive design tools over those with static snapshots of the same material. Interactive design tools also improved performance on the design problems. However, performance on the follow-up quizzes did not vary among student cohorts regardless of presentation format. Similarly, although students generally enjoyed and valued group work activities, and although these experiences frequently increased students' confidence in their answers, follow-up quiz performance was not enhanced by group work activities. In an unanticipated result, students were twice as likely to sketch their answers when the module itself contained animated illustrations rather than static graphic material. This result suggests that computer-based learning tools can significantly affect the character and texture of students' representation of their own ideas in manners that do not emerge from traditional performance measures     

A comparison of A103 and inhibin reactivity in adrenal cortical tumors: distinction from hepatocellular carcinoma and renal tumors

Distinguishing adrenal cortical neoplasms from either hepatocellular carcinomas or renal tumors can be difficult. Two recently described antibodies, A103 and inhibin A, are most often reported to be reactive with adrenal cortical neoplasms but with neither hepatocellular carcinoma nor renal cell carcinoma. To compare the sensitivity and specificity of these two antibodies in the diagnosis of adrenal cortical tumors, we stained 22 adrenal cortical adenomas, 4 adrenal cortical carcinomas, 25 hepatocellular carcinomas, and 43 renal tumors, including 33 renal cell carcinomas and 8 oncocytomas, with the A103 and inhibin A using an avidin-biotin complex technique. Fifteen (68%) of 22 adrenal adenomas and 2 (50%) of 4 adrenal cortical carcinomas were reactive with A103. Nineteen (86%) of 22 adrenal adenomas and 3 (75%) of 4 adrenal cortical carcinomas were reactive for inhibin A. None of the renal tumors or hepatocellular carcinomas reacted with A103, but 1 (4%) of 25 hepatocellular carcinomas (a high-grade pleomorphic tumor) and 1 (2%) of 43 renal tumors (a clear-cell renal cell carcinoma) were reactive with inhibin A. The cytoplasmic reactivity for A103 in adrenal tumors was coarsely granular and most common in clear-cell areas. Reactivity for inhibin was either cytoplasmic or membranous and stained both clear-cell and granular areas. We conclude that both antibodies are useful in the immunohistochemical diagnosis of adrenal cortical neoplasms and that A103 is slightly more specific and inhibin slightly more sensitive.