cssi/SciSciGPT-SciSciNet huggingface dataset:
Incorporating Compatible Pairs in Kidney Exchange: A Dynamic Weighted Matching Model

Kidney exchange has been studied extensively from the perspective of market design, and a significant focus has been on better algorithms for finding chains and cycles to increase the number of possible matches. A more dramatic benefit could come from incorporating compatible pairs into the mechanism, but this possibility has been relatively understudied. In order to incentivize a compatible pair to participate in exchange, they must be offered a higher quality match for the recipient that can be performed without adding extra waiting time. In this paper, we make two main contributions to the study of incorporating compatible pairs in exchanges. First, we leverage the recently proposed Living Donor Kidney Profile Index (LKDPI) to measure match quality, and develop a novel simulator (based on data from a major transplant center) for the joint distribution of compatibility and quality across pairs. This simulator allows us to study the benefits of including compatible pairs under different models and assumptions. Second, we introduce a hybrid online/batch matching model with impatient (compatible) and patient (incompatible) pairs to capture the need for immediacy. We introduce new algorithms for matching in this model, including one based on online primal-dual techniques. Overall, our results indicate great potential in terms of both increased numbers of transplants of incompatible pairs (almost doubling the number transplanted) as well as improved match quality for recipients in compatible pairs (increasing expected graft survival by between 1 and 2 years). The results are also promising for hard-to-match subpopulations, including blood group O recipients.
Arabic language-learning strategy preferences among undergraduate students

This study elicited Arabic students’ perceptions regarding their language-learning strategy preferences (LLSPs). A sample of 120 undergraduate Arabic students participated. Data were collected through a questionnaire and interviews. The findings reveal that students tend to adopt a holistic view of the learning task and relate it to real-life, personal experience. Participants selected interaction with the teacher, speaking, and flashcards as their most preferred application-directed learning strategies. These selections demonstrate that Arabic students desire to be proactive in order to make the language more concrete for them, to enhance their performance, and to develop language skills that will last a lifetime. Whereas advanced level participants preferred interaction with the teacher, speaking, flashcards, and working individually, beginner level participants preferred learning grammar and group work. The empirical evidence from this study could have implications regarding theoretical models of effective Arabic language instruction, Arabic teacher education programs, and curriculum development.
Factors contributing to scholarly productivity of assistant professors in counseling

Doctoral research training and faculty departmental research culture were explored in relation to research interest, self-efficacy, and productivity among 49 counselor education assistant professors. Doctoral research training environment consistently held strong positive relationships with research interest and self-efficacy, suggesting that a solid foundation in research at the doctoral level is imperative for initial research productivity.
Real Solutions of y″ = Ay2 + 2By + C

(1976). Real Solutions of y″ = Ay2 + 2By + C. The American Mathematical Monthly: Vol. 83, No. 2, pp. 129-131.
Fuel Cell Vehicles

Fuel cells operating on hydrogen are among the propulsion technologies seeing research, development and demonstration as an option for meeting transportation needs in a world that faces severe limits on net anthropogenic CO 2 emissions. This article describes fuel cell vehicles, their principles of operation and major components while discussing the progress made in advancing the technology, the challenges it faces and its prospects for the future. Although various fuel cells can use different fuels, polymer electrolyte membrane (PEM) cells that use pure hydrogen are viewed as the best choice for motor vehicles. Fully capable automobiles using PEM fuel cells have been demonstrated and significant cost reductions are in sight for the vehicles themselves. Technical and economic hurdles remain for on-board hydrogen storage, refueling systems and hydrogen supply infrastructure. Fuel cell vehicles will also face competition from ongoing improvements in gasoline vehicles, including hybrid-electric designs, and in small car segments from battery electric vehicles. The economics of all such options will be evaluated in a context that includes increasing vehicle connectivity and automation as well as progress in the control of energy sector CO 2 emissions and programs for offsetting CO 2 emissions, particularly from liquid fuel use. Nevertheless, because of the promise they hold for meeting energy and climate challenges, fuel cell vehicles have captured the interest of governments and transportation industries around the world, and may become a viable choice for mobility systems of the future.
∅sim: Preparing System Software for a World with Terabyte-scale Memories

Recent advances in memory technologies mean that commodity machines may soon have terabytes of memory; however, such machines remain expensive and uncommon today. Hence, few programmers and researchers can debug and prototype fixes for scalability problems or explore new system behavior caused by terabyte-scale memories. To enable rapid, early prototyping and exploration of system software for such machines, we built and open-sourced the ∅sim simulator. ∅sim uses virtualization to simulate the execution of huge workloads on modest machines. Our key observation is that many workloads follow the same control flow regardless of their input. We call such workloads data-oblivious. 0sim harnesses data-obliviousness to make huge simulations feasible and fast via memory compression. ∅sim is accurate enough for many tasks and can simulate a guest system 20-30x larger than the host with 8x-100x slowdown for the workloads we observed, with more compressible workloads running faster. For example, we simulate a 1TB machine on a 31GB machine, and a 4TB machine on a 160GB machine. We give case studies to demonstrate the utility of ∅sim. For example, we find that for mixed workloads, the Linux kernel can create irreparable fragmentation despite dozens of GBs of free memory, and we use ∅sim to debug unexpected failures of memcached with huge memories.
Non-ventilator health care associated pneumonia (NV-HAP): Oncology

Literature suggests that cancer patients can become colonized or infected with a variety of opportunistic and health care-associated pathogens, putting them at higher risk for nonventilator health care-associated pneumonia. This section will review the epidemiology of nonventilator health care-associated pneumonia and the importance of prevention strategies in this vulnerable population. Prevention strategies for cancer patients across the continuum of care are highlighted.
Abstract PR14: Defining isoform-specific roles for AKTs in BRAFV600E-driven melanoma

The PI3K/AKT pathway is frequently dysregulated in cutaneous melanoma and impacts both tumor aggression and resistance to BRAFV600E/K inhibitors. While current clinical approaches to AKT inhibition are severely limited by the toxicity of pan-AKT inhibitors, selective inhibition of individual AKT isoforms (AKT1, AKT2, or AKT3) remains an attractive, if yet unattainable, approach. A critical gap in our understanding concerns how the three highly homologous yet functionally distinct AKT isoforms contribute to melanomagenesis and treatment response. To address this question, we are employing RNAi and gene editing approaches to interrogate the effect of selective suppression or CRISPR/Cas9-mediated deletion of each isoform in vitro, as well as the impact of AKT isoform loss on 1) the growth of melanoma xenografts and 2) the development of spontaneous tumors in a melanoma-prone mouse model. In addition, we are interrogating tumor-promoting functions of AKT isoform-selective substrates recently identified in a phospho-proteomic screen of mouse fibroblasts, a system that allows us to identify downstream actionable targets that may mediate the effects of AKT isoforms in tumorigenesis. Broadly, we are focusing on the importance of AKTs in tumor cell growth, metastasis, and response to inhibitors of BRAFV600E/K or CDK4/6. We find that loss of AKT1 impacts growth of BRAF mutant human melanoma cells both in vitro and in vivo. Additionally, AKT1 appears to play an isoform-specific role in response to pharmacologic CDK4/6 inhibition, impacting transcriptional and morphologic changes typically associated with permanent cell cycle arrest. In contrast, loss of AKT2 has a minimal impact on melanoma cell growth or response to CDK4/6 inhibition, but severely limits the development of metastatic disease, potentially through a combination of impaired seeding at the metastatic site and defects in glycolysis. While AKT3 loss does not appreciably impact the above-mentioned cellular phenotypes, the protumorigenic role of AKT3 may involve activation of broadly-acting neutral proteases previously implicated in cell cycle progression, cell migration, and CDK5 regulation. Taken together, we provide evidence for distinct roles for AKT isoforms in several aspects of the tumorigenic process as well as response to current therapies. Future studies will focus on identification and targeting of the relevant downstream mediators of these phenotypes. This abstract is also being presented as Poster A16. Citation Format: Jaymes Farrell, Jodie Pietruska, Siobhan McRee, Philip Tsichlis, Philip Hinds. Defining isoform-specific roles for AKTs in BRAFV600E-driven melanoma [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR14.
Feasibility of Rapid Development and Deployment of a Telemedicine Program in a Foot and Ankle Orthopedic Practice.

Background:A lack of access to care is predictably associated with negative outcomes in foot and ankle surgery. Despite recent advances in telecommunication technologies, the field of orthopedics h...
The Tie That Binds: Exploring Community College Curriculum Design

More students are beginning their college careers at community colleges before completing degrees at four-year institutions. As enrollments swell at these two-year institutions, issues surrounding transfer and articulation agreements are increasingly important, and two- and four-year institutions must work together on the recruitment, retention, and transition of political science majors. Central to this collaboration is the curriculum. Building on conclusions from the 2011 Leadership Collaborative Core Curriculum and General Education track regarding a common curriculum in the discipline, this article examines the political science curriculum using data from 47 two-year colleges with separate political science departments. We examined similarities and differences among these programs and found sufficient commonality in curriculum to allow students to transfer credits to four-year institutions. The article also offers community colleges an indication of common curricular features and informs the wider profession about community college curriculum design.
Continuous compliance

Vendors who wish to provide software or services to large corporations and governments must often obtain numerous certificates of compliance. Each certificate asserts that the software satisfies a compliance regime, like SOC or the PCI DSS, to protect the privacy and security of sensitive data. The industry standard for obtaining a compliance certificate is an auditor manually auditing source code. This approach is expensive, error-prone, partial, and prone to regressions. We propose continuous compliance to guarantee that the codebase stays compliant on each code change using lightweight verification tools. Continuous compliance increases assurance and reduces costs. Continuous compliance is applicable to any source-code compliance requirement. To illustrate our approach, we built verification tools for five common audit controls related to data security: cryptographically unsafe algorithms must not be used, keys must be at least 256 bits long, credentials must not be hard-coded into program text, HTTPS must always be used instead of HTTP, and cloud data stores must not be world-readable. We evaluated our approach in three ways. (1) We applied our tools to over 5 million lines of open-source software. (2) We compared our tools to other publicly-available tools for detecting misuses of encryption on a previously-published benchmark, finding that only ours are suitable for continuous compliance. (3) We deployed a continuous compliance process at AWS, a large cloud-services company: we integrated verification tools into the compliance process (including auditors accepting their output as evidence) and ran them on over 68 million lines of code. Our tools and the data for the former two evaluations are publicly available.
Orientation-dependent, field-induced phase transitions in soft lead zirconate titanate piezoceramics

Abstract In situ high-energy X-ray diffraction (XRD) was performed on lead-zirconate-titanate-based ferroelectric materials with composition near the morphotropic phase boundary (MPB). The utilization of the two-dimensional area detector in in situ field-dependent experiments enables the complete analysis of the material response with respect to all azimuthal angles at each field amplitude. The studies reveal that the field-induced phase transition from tetragonal to rhombohedral is dependent on crystal orientation in Nb-doped PbZr0.53Ti0.47O3 that is in close compositional proximity to the MPB. However, only domain wall motion is activated in Nb-doped PbZr0.50Ti0.50O3, which is further in composition from the MPB. This synchrotron-based XRD characterization approach illustrates the importance in evaluating the orientation-dependence of phase transitions in piezoelectric and ferroelectric polycrystalline materials.
Far Infrared Generation by Noncollinear Difference Frequency Mixing

New developments in far infrared generation by noncollinear mixing of CO 2 lasers in GaAs and CdTe are presented. In particular, new folded crystal geometries which can yield orders of magnitude increase in the output power are discussed.
Autoantibodies to red blood cell surface Glycophorin A impact the activation poise of circulating leukocytes.

BACKGROUND Both M and N alleles encode antigens on Glycophorin A (GPA), a red blood cell (RBC) surface sialoglycoprotein. Interaction between RBC GPA and leukocyte surface lectins may downregulate their activation. The current study investigates if RBC autoantibodies against GPA, such as auto-anti-M/N, prime an activated phenotype in peripheral blood leukocytes. METHODS Leukocyte activation was assessed in whole blood from patients with auto-anti-GPA (anti-M/N) and compared to those with allo-anti-M/N and healthy subjects. Control samples from healthy subjects with no antibodies incubated in vitro with either anti-GPA or anti-Rh were analyzed for neutrophil and monocyte surface activation marker expression, reactive oxygen species (ROS) content, and formation of aggregates with RBCs. Samples incubated with an IgG1 isotype antibody served as controls. RESULTS Ex vivo, neutrophil CD66b and monocyte CD63 surface expression was increased in patients with auto-anti-M/N compared to those with allo anti-M/N (p = .1757; p = .0698) and to healthy subjects (p = .0186; p = .013). In vitro, neutrophil CD66b and monocyte CD63 surface expression was increased following incubation with anti-GPA compared to anti-Rh (p = .0003; p = .0328) and isotype control (p = .000; p = .0062). Intracellular ROS content increased in both neutrophils and monocytes incubated with anti-GPA compared to anti-Rh (p = .0012; p = .0693) and isotype control (p = .001; p = .0021). Percentage of neutrophil-RBC aggregates was decreased when incubated with anti-GPA compared to isotype control (p < .01). CONCLUSIONS Neutrophils and monocytes in peripheral blood exposed to an antibody directed against GPA on RBC surfaces, such as M or N antigens, may be primed towards an activated phenotype.
Under time pressure, the exogenous modulation of saccade plans is ubiquitous, intricate, and lawful.

Abstract The choice of where to look next is determined by both exogenous (bottom-up) and endogenous (top-down) factors, but details of their interaction and distinct contributions to target selection have remained elusive. Recent experiments with urgent choice tasks, in which stimuli are evaluated while motor plans are already advancing, have greatly clarified these contributions. Specifically, exogenous modulations associated with stimulus detection act rapidly and briefly (∼25 ms) to automatically halt and/or boost ongoing motor plans as per spatial congruence rules. These stereotypical modulations explain, in quantitative detail, characteristic features of many saccadic tasks (e.g. antisaccade, countermanding, saccadic-inhibition, gap, and double-step). Thus, the same low-level visuomotor interactions contribute to diverse oculomotor phenomena traditionally attributed to different neural mechanisms.
Electrochemical and scanning probe microscopic characterization of spontaneously adsorbed organothiolate monolayers at gold

This dissertation presented several results which add to the general knowledge base regarding organothiolates monolayer spontaneously adsorbed at gold films. Common to the body of this work is the use of voltammetric reductive resorption and variants of scanning probe microscopy to gain insight into the nature of the monolayer formation process as well as the resulting interface. The most significant result from this work is the success of using friction force microscopy to discriminate the end group orientation of monolayer chemisorbed at smooth gold surfaces with micrometer resolution (Chapter 4). The ability to detect the differences in the orientational disposition is demonstrated by the use PDMS polymer stamp to microcontact print an adlayer of n-alkanethiolate of length n in a predefine pattern onto a gold surface, followed by the solution deposition of a n-alkanethiol of n {+-} 1 to fill in the areas on the gold surface intentionally not coated by the stamping process. These two-component monolayers can be discriminated by using friction force microscopy which detects differences in friction contributed by the differences in the orientation of the terminal groups at surfaces. This success has recently led to the detection of the orientation differences at nanometer scale. Although the substrates examined in this work consisted entirely of smooth gold films, the same test can be performed on other smooth substrates and monolayer materials.
Influence of oil extraction method on properties of canola biodiesel, epoxies, and protein-based plastics

Abstract Canola oil was extracted using a liquid carbon dioxide extraction process (LCE), laboratory screw-pressing, and industrial solvent extraction. Oilseed meal generated from these methods was used to extract proteins for protein-based plastics, and the oil was used to produce both epoxy resins and biodiesel. Protein isolates obtained from the LCE-generated meal produced plastics with higher toughness and elongation, but lower tensile strength and modulus, than those using meal obtained from screw pressing and solvent extraction. The oils extracted using the LCE process produced cured epoxy resins with higher flexural modulus than those produced from solvent-extracted oil. However, dynamic mechanical properties such as storage and loss modulus showed no significant differences with respect to oil extraction method. Oils obtained from extraction methods had similar fatty acid profiles and produced biodiesel with no significant differences in properties.
The factor structure of the Pittsburgh Sleep Quality Index in persons with traumatic brain injury. a NIDRR TBI model systems module study

BACKGROUND: Sleep disturbances are common following traumatic brain injury (TBI). The Pittsburgh Sleep Quality Index (PSQI) is a widely used measure of sleep quality that has been used in numerous populations. Although this measure has been used in TBI research, there are few studies examining the psychometric properties in this population. OBJECTIVE: The current study examined the factor structure of the PSQI in a sample of persons with TBI and tested the one, two, and three factor models derived from previous studies in other populations. METHODS: A telephone interview was conducted with 243 individuals who had sustained a TBI. All participants were approximately one year post-injury. Factor analyses were conducted (exploratory and confirmatory) to examine the factor structure of the PSQI. RESULTS: Results confirm the fit of models previously tested in the literature but also reveal an alternative conceptualization of sleep containing both qualitative and quantitative factors. CONCLUSIONS: While the 3-factor model best fits the data in this TBI sample, the use of a 2-factor model is acceptable and may be more clinically relevant due to the grouping of time-related variables that could provide important information with regard to circadian rhythm disorders. Language: en
Languages of DNA Based Code Words

The set of all sequences that are generated by a biomolecular protocol forms a language over the four letter alphabet Δ={A,G,C,T}. This alphabet is associated with a natural involution mapping θ, A↦ T and G↦ C which is an antimorphism of Δ*. In order to avoid undesirable Watson-Crick bonds between the words (undesirable hybridization), the language has to satisfy certain coding properties. In this paper we build upon the study initiated in [11] and give necessary and sufficient conditions for a finite set of “good” code words to generate (through concatenation) an infinite set of “good” code words with the same properties. General methods for obtaining sets of “good” code words are described. Also we define properties of a splicing system such that the language generated by the system preserves the desired properties of code words.
English‐as‐a‐Second‐Language Programs for Matriculated Students in the United States: An Exploratory Survey and Some Issues

Although English-as-a-second-language (ESL) programs for matriculated students have been a presence in U.S. higher education since the 1940s, little has been documented in the literature concerning ESL courses, ESL placement tests, and the procedures in which incoming students are placed into appropriate classes. The present study takes three approaches to explore the characteristics of ESL programs for matriculated students, with the purposes of drawing a clearer picture of such programs and preparing for a further exploration of validity issues that arise when using standardized English proficiency tests, such as the TOEFL® test, to assist with ESL placement decisions. We reviewed the websites of 152 postsecondary institutions, obtained information from 80 institutions through an online survey, and interviewed representatives of 24 ESL programs for matriculated students. Analyses of these three sources of data revealed that ESL programs for matriculated students exist in more than half of colleges and universities sampled, that they provide a wide range of ESL courses focusing on different language skills, and that these programs make use of a variety of placement tests and procedures. We summarize these different placement procedures using a general model, highlight issues that need further investigations, and conclude with key findings and limitations.
Petrogenesis of Sapphirine‐Bearing Metatroctolites from the Buck Creek Ultramafic Body, Southern Appalachians

The Buck Creek ultramafic body, North Carolina, includes aluminous lenses that have been described as troctolites. These lenses preserve mineral assemblages which record several different stages of metamorphism. The first stage is characterized by anhydrous reactions between olivine and plagioclase to produce coronas of orthopyroxene+ clinopyroxene/spinel symplectite. Thermo barometric results indicate minimum pressures of c. 6 kbar and c. 800 oC. Sapphirine replaces spinel in some clinopyroxene symplectites, and occurs as anhedral grains within amphibole, observations which in combination suggest peak metamorphic conditions of c. 9-10 kbar and c. 850 oC. Sapphirine-bearing hydrous assemblages formed at the expense of the coronas, indicating a second metamorphic episode involving deeper burial, deformation and hydration. Schistose rocks from the margins of the lenses are composed of anorthite+amphibole+margarite+corundum, and probably record a later, lower P-T event. Whole rock analyses for the Buck Creek lenses suggest an accumulate protolith of magnesian olivine and calcic plagioclase. Trace element data for the troctolites are consistent with data for adjacent amphibolites in suggesting that the Buck Creek mafic and ultramafic cumulates crystallized from magmas derived from a mantle source similar to that which produces modern intraplate or rift-related basalts. We propose that the Buck Creek ultramafics represent basal cumulates(± uppermost mantle) from ocean crust formed in a marginal basin in the latest Precambrian. Subduction-induced burial to at least 18 km under dry conditions induced corona formation. Collisional events of the Taconic orogeny thrust the Buck Creek rocks into the orogenic pile to at least 30 km depth and hydrated them along zones of weakness, locally producing P-T -PH2O conditions appropriate for formation of sapphirine and hydrated assemblages, but still preserving some dry symplectites.
Characterization and expression of nuclear-encoded polyketide synthases in the brevetoxin-producing dinoflagellate Karenia brevis.

The dinoflagellate Karenia brevis (C. C. Davis) Gert Hansen et Moestrup produces a suite of brevetoxins, potent neurotoxins that have adverse effects on marine animal and human health. Brevetoxins are polyketides proposed to be synthesized by polyketide synthases (PKSs), and genes for type I PKSs have been predicted by PCR and transcript analysis. However, the full-length transcripts in K. brevis predict an unusual protein structure for type I PKS in that individual transcripts encode for single catalytic domains. In this study, we developed peptide antibodies to in silico translated transcripts for two PKS proteins to characterize their expression and localization. Immunoreactive proteins identified by Western blotting at 40 kDa (KR domain) and 100 kDa (KS domain) are consistent with the sizes predicted by the full-length transcripts. Immunolocalization and Western blot analysis indicate that these PKSs are associated with the chloroplasts. In order to establish evidence for a role in brevetoxin biosynthesis, PKS transcript and protein levels were examined in a “nontoxic”K. brevis substrain and its parental toxic isolate, K. brevis Wilson. DNA microarray analysis of the global transcript profiles in the “nontoxic” isolate showed that ∼7% of transcripts were differentially expressed, including photosystem genes; however, no difference was observed in PKS transcript abundance. By contrast, KS domain proteins were 55%–70% less abundant in “nontoxic”K. brevis cultures compared to toxic cultures. This finding suggests that K. brevis PKS expression is regulated posttranscriptionally, like many other processes in dinoflagellates. Further, the decrease in PKS protein abundance in the “nontoxic” cultures provides correlative evidence for their involvement in brevetoxin biosynthesis.
Delayed success of balloon dilation for coexisting pulmonary valve stenosis and sinotubular narrowing.

Objectives We evaluated the outcomes of children at a single institution who underwent balloon pulmonary valvuloplasty (BPV) for coexisting pulmonary valve stenosis (PVS) and sinotubular narrowing (STN). Background BPV is the treatment of choice for PVS in children. Current practice favors surgical repair of moderate, severe, and symptomatic pulmonary stenosis when STN exists. This practice arose from lack of reduction in total pulmonary gradient (TPG) and frequent adverse events from BPV. Methods A retrospective analysis of outcomes in children with coexisting PVS and STN following BPV at a single institution was performed. Results Twenty-three patients were identified. Median age at BPV was 0.5 years (interquartile range (IQR) 0.3–2). Surgery was avoided in 15/23 (65%) (Group 1) and required in 8/23 (35%) (Group 2) following BPV. Group 1 had a mean baseline peak echo TPG of 60 mm Hg (±12) that decreased to 44 mm Hg (±10) following BPV (P < 0.01) and further to 21 mm Hg (±13) at 3.6 years (±2.2) following BPV (P < 0.01). Group 2 had a mean baseline peak echo TPG of 68 mm Hg (±17). TPG was unchanged by first echo after BPV at 56 mm Hg (±13) and just prior to surgery at 63 mm Hg (±15) (P > 0.10). Conclusions BPV has minimal acute effect on PVS when STN exists; however; long-term benefits are achieved in most. BPV should be considered first-line therapy given its safety and effectiveness. Only those with worsening clinical signs and symptoms should be referred for surgical repair following BPV.
Detecting a quasi-stable imine species on the reaction pathway of SHV-1 β-lactamase and 6β-(hydroxymethyl)penicillanic acid sulfone.

For the class A β-lactamase SHV-1, the kinetic and mechanistic properties of the clinically used inhibitor sulbactam are compared with the sulbactam analog substituted in its 6β position by a CH2OH group (6β-(hydroxymethyl)penicillanic acid). The 6β substitution improves both in vitro and microbiological inhibitory properties of sulbactam. Base hydrolysis of both compounds was studied by Raman and NMR spectroscopies and showed that lactam ring opening is followed by fragmentation of the dioxothiazolidine ring leading to formation of the iminium ion within 3 min. The iminium ion slowly loses a proton and converts to cis-enamine (which is a β-aminoacrylate) in 1 h for sulbactam and in 4 h for 6β-(hydroxymethyl) sulbactam. Rapid mix–rapid freeze Raman spectroscopy was used to follow the reactions between the two sulfones and SHV-1. Within 23 ms, a 10-fold excess of sulbactam was entirely hydrolyzed to give a cis-enamine product. In contrast, the 6β-(hydroxymethyl) sulbactam formed longer-lived acyl–enzyme in...
Topical mechlorethamine in the treatment of mycosis fungoides : uniformity of application and potential for environmental contamination

Topical mechlorethamine hydrochloride is commonly used in the treatment of mycosis fungoides and has been formulated in both aqueous and ointment vehicles. Two concerns regarding the topical application of mechlorethamine hydrochloride relate to the adequacy of skin coverage that can be attained by the patient and the extent to which others in the patient's household might be exposed to the drug. In this study six patients applied either aqueous or ointment vehicles containing a fluorescent dye. Subsequent examination of the skin under a Wood's lamp revealed a significant percentage of body surface area to be missed during application; several areas were noted to be missed most commonly. These observations have led to specific alterations in instructions given to patients regarding drug application. Examination of the surrounding environment showed minimal evidence of contamination.
Risk and Resilience Factors Linked to Problem Behavior Among Urban, Culturally Diverse Adolescents

We examined several risk and resilience factors associated with sexual intercourse, gang involvement, and alcohol and drug use among 332 urban, culturally diverse adolescents aged 12 to 16 years. I...
Lessons from epidemiologic studies in clinical trials of traumatic brain injury.

The Clinical Trial Group for Neurosurgery of the University of California San Diego (UCSD) is involved in epidemiological studies and trials of new pharmacological agents in traumatic brain injury. A great number (> 10,000) of patients has been prospectively analyzed forming an integrated database for further purposes. The development of these databases is based on earlier work by the European Neurosurgeons Jennett and Braakmann and the US-Traumatic Coma Data Bank Study. These studies allowed for the development of sophisticated data collection instruments which were used in the international Tirilizad Trials which enrolled over 1,100 patients. A major observation from that trial was that pretreatment hypotension or hypoxia could be unbalanced even in a large two arm blinded study. Another issue of the tirilazad trial was the influence of gender affecting not only outcome but also drug metabolism.
Inter‐ and Intratester Reliability of Anthropometric Assessment of Limb Circumference in Labrador Retrievers

Objective To report a standardized method of, and determine inter- and intratester reliability for, anthropometric assessment of limb circumference in dogs. Study Design Prospective blinded study. Animals Labrador Retrievers (n = 20). Method Unsedated dogs were manually restrained in lateral recumbency and triplicate measurements of limb circumference at the level of the proximal antebrachium, mid brachium, proximal crus, and mid-thigh were made using the Gulick II tape measure in the morning and afternoon of the same day. Observers were blinded to measurements made during each occasion and those made by co-observers. Estimates of inter- and intratester reliability were made for first and mean measurements using intra-class correlation coefficients (ICC). Results Measurements of the proximal antebrachium were made with moderate to fair intratester reliability by all observers with ICC's ranging from 0.68–0.78 (1st measurement) and 0.67–0.78 (mean measurement), and moderate to fair intertester reliability with ICC's of 0.66–0.68 (1st measurement) and 0.70–0.72 (mean measurement). Measurements of the brachium, crus, and thigh typically had poor inter- and intratester reliability, ICC < 0.5. Conclusion Using the described method of muscle measurement in Labrador Retrievers only measurement of the proximal antebrachium was reliable; a single (1st) measurement was as reliable as using the mean of triplicate measurements.
Control of Cross-Contamination

High-speed, air-driven handpieces and dental burs are contaminated after use and thus they can be a source of cross-contamination of patients. The effectiveness of the disinfectant solutions of benzalkonium chloride and aqueous activated 2% glutaraldehyde was compared in tests involving suspensions of two microorganisms. The glutaraldehyde solution was bacteriocidal within five minutes in tests involving Streptococcus pyogenes, and within three hours in tests with Bacillus stearothermophilus. Benzalkonium chloride appeared to be less effective.
Experimental Methods to Detect and Quantify Damage in Restrained Concrete Ring Specimens

This paper describes the use of three experimental methods to detect shrinkage cracking in restrained ring specimens. These methods include monitoring the strain at the inner surface of the restraining steel ring, using passive acoustic emission, and measuring the electrical resistance of conductive materials that are applied to the surface of the mortar. The methods for detecting cracking are compared and their advantages and limitations are discussed. Both plain and steel fiber reinforced (2% steel fiber by volume) mortar were evaluated in this study. The time of through cracking detected by the three methods corresponds to the time of visible cracking. In the mixtures containing fibers the time of through cracking is delayed significantly when compared to the plain systems. The delay in the age of through cracking can be explained by the role of fibers in arresting the cracks as they develop and their role in transferring stress across the crack width that keeps the cracks from opening. The passive acoustic emission data indicates substantial damage development before a through crack forms. The time of through cracking can be detected using conductive surfaces with a sudden increase in resistance of these conductive elements. Cracking can be detected using conductive coatings when the crack is 0.02 mm or larger. Specimens with different degrees of restraint show through cracking at approximately the same stress level; however, the age at which cracking occurs decreases as the degree of restraint increases. This can be attributed to the increased micro-cracking (i.e., damage and precritical crack growth) as confirmed with acoustic emission data.
Five-year experience with the maze procedure for atrial fibrillation

Abstract Between September 25, 1987, and December 31, 1992, 75 patients (53 men, 22 women; average age, 52 years) underwent the maze procedure for the treatment of atrial fibrillation. Six patients had undergone a previous cardiac operation and 28% underwent concomitant cardiac procedures in addition to the maze procedure. One patient (1.3%) died 10 days after undergoing a combined maze procedure and Morrow procedure for the management of chronic atrial fibrillation and hypertrophic obstructive cardiomyopathy. Postoperative atrial pacemakers were required in 40%:26% for preoperative sick sinus syndrome and 6% for iatrogenic injury of the sinus node, and 8% had pacemakers in place preoperatively. As of December 31, 1992, 65 patients had been followed up for at least 3 months after operation (range, 3 to 63 months). The maze procedure cured atrial fibrillation, restored atrioventricular synchrony, and preserved atrial transport function in 64 of 65 patients (98%). The procedure has been curative without the need for medications in 58 of 65 patients (89%) and with the need for medications in 6 of 65 (9%), with medications failing in only 1 of the 65 patients (2%). The results support the maze procedure as the treatment of choice in patients with medically refractory symptomatic atrial fibrillation.
Ethical review of global short-term medical volunteerism.

Global short-term medical volunteerism is growing, and properly conducted, is a tool in the fight for greater global health equity. It is intrinsically “ethical” (i.e., it involves ethics at every step) and depends upon ethical conduct for its success. At present, ethical guidelines remain in their infancy, which presents a unique opportunity. This paper presents a set of basic ethical principles, building on prior work in this area and previously developed guidelines for international clinical research. The content of these principles, and the benchmarks used to evaluate them, remain intentionally vague and can only be filled by collaboration with those on-the-ground in local communities where this work occurs. Ethical review must additionally take into consideration the different obligations arising from the type of institution, type of intervention, and type of relationship involved. This paper argues that frequent and formalized ethical review, conducted from the beginning with the local community (where this community helps define the terms of debate), remains the most important ethical safeguard for this work.
Prenatal manipulations reduce the proinflammatory response to a cytokine challenge in juvenile monkeys

Two studies were conducted to assess the potential long-term effects of prenatal stress on the cytokine-related inflammatory response in juvenile rhesus monkeys. Subjects were derived from two different pregnancy conditions. Study 1 involved endocrine activation of the pregnant female by daily adrenocorticotropic hormone (ACTH) injection across a 2-week period (days 120-133 post-conception). Pregnant females in Study 2 experienced a psychological stressor, 10 minutes per day, for a 6-week period (days 106-147 post-conception). When the offspring from these pregnancies were 1.5-2 years of age, they were administered recombinant human interleukin-1beta (rhIL-1beta) to stimulate the release of endogenous cytokines, elicit fever, and activate the hypothalamic-pituitary-adrenal (HPA) axis. Cerebrospinal fluid (CSF) and blood levels of interleukin-6 (IL-6) were measured, as well as cortisol levels and body temperature. The prenatal ACTH treatment altered the postnatal response to IL-1beta in juvenile offspring. These monkeys showed a significantly blunted response to the IL-1beta, with smaller increments in blood and CSF levels of IL-6 and diminished temperature responses to the IL-1beta. In contrast, the prenatal psychological stressor was not as potent and did not have lasting effects on this physiological response in juvenile monkeys. IL-1beta also induced significant increases in cortisol secretion, but this adrenal response was comparable in all monkeys. These data suggest that differences in the prenatal environment could have a selective effect on cytokine physiology accounting for individual differences in the inflammatory response.
High‐Energy Trapped Radiation Penetrating the Rings of Saturn

Electrons and protons of energies from 2 to 25 MeV and greater than 67 MeV, respectively, have been discovered throughout the entire equatorial region inward from the outer edge of the A ring at L = 2.3 to the periapsis of the Pioneer trajectory at L = 1.3. The trapped radiation found in Saturn's magnetosphere beyond L = 2.3 is totally absent here. The present paper deals with the measurements in this region under the rings, and their interpretation.
Note: Applying a combinatorial determinant to count weighted cycle systems in a directed graph

One method for counting weighted cycle systems in a graph entails taking the determinant of the identity matrix minus the adjacency matrix of the graph. The result of this operation is the sum over cycle systems of -1 to the power of the number of disjoint cycles times the weight of the cycle system. We use this fact to reprove that the determinant of a matrix of much smaller order can be computed to calculate the number of cycle systems in a hamburger graph.
Spontaneous Astomy: Loss of Oral Areas in Glaucoma chattoni*

Specimens of Glaucoma chattoni lacking in oral areas and unable to divide were observed in both axenic and bacterized cultures. The frequency of incidence of astomy rose in the course of continued cultivation of G. chattoni A, which was the strain most extensively studied. Observations on silver impregnated animals from mass cultures, and studies of individually isolated living ciliates, have both led to the conclusion that all cells destined to become astomous pass through a certain definite sequence of events. These axe: 1. Initial damage, not microscopically detectable, predisposes the cell in such a way that within a few generattons all of its progeny become astomous. 2. The ability to complete normal stomatogenesis is lost; the cell cannot maintain normal posterior oral anlagen and also cannot regenerate following damage to the existing oral area. At this stage the cell can still divide, so that astomous opisthes are produced. 3. The existing oral area disappears shortly after the ability to produce new oral areas is lost. Loss of ability to divide occurs simultaneously with loss of oral areas. 4. Finally, there is increasing disorganization of the kineties, gradually decreasing activity and death. The incidence of astomy was compared in several different strains of G. chattoni, including two newly isolated from nature.
Economics of long-term IPM for western corn rootworm

We used a published biological model and published economic algorithm to evaluate western corn rootworm (Diabrotica virgifera virgifera) IPM for growers over a 15 year period beginning after significant adoption of insecticidal corn (Zea mays). The primary focus of our analysis was the economic evaluation (grower profit) of transgenic insecticidal corn expressing Cry34/35Ab1 as event 59122 and its refuge planted continuously year after year (continuous corn). We chose the reference scenario for economic comparison to be the use of soil insecticides on continuous, conventional corn. The model simulated the evolution of rootworm resistance to transgenic insecticidal (Bt) corn; but did not simulate resistance to soil insecticides. We evaluated refuge sizes of 5–50% for single-trait Bt corn and 5–20% for pyramided Bt corn with two traits targeting western corn rootworm. We considered the role of block and blended (seed mixture) refuges for insect resistance management (IRM). Results demonstrated that, for pyramided Bt corn, block refuges planted in the same location within a field year after year gave the greatest overall profit for grower. If growers relocated their block refuge annually (which is the most common practice), then a 5% blended refuge gave the greatest return. For single-trait Bt corn, 10–20% blended refuges gave greater economic return compared to block refuges ranging from 5% to 50%. Single-trait Bt corn with 5–20% block refuge (with no insecticide) was superior to soil insecticide use alone in all cornfields.
In vitro and in vivo enzymatic dissolution of the plerocercoid body of Spirometra mansonoides (Cestoidea).

Abstract In vitro incubation of intact plerocercoids of Spirometra mansonoides in Medium 199 with Earle's salts and 25 mM HEPES plus antibiotics and containing per ml 20 mg sodium taurocholate, 10 mg trypsin and 4 mg glutathione (reduced) under a gas phase of 95% N2/5% CO2 at 37°C resulted in complete dissolution of the plerocercoid body within 5 h. Trypsin was found to be the active enzyme involved in body dissolution. Plerocercoid body dissolution did not occur during in vitro incubation in either sodium taurocholate, glutathione, α-chymotrypsin (TLCK treated), or pepsin. Ultrastructural changes in the tegument of the plerocercoid body after 45 min of in vitro incubation included vesiculation of the tegument, swelling of the tegumental cytoplasm, and blebbing of the distal tegumental plasma membrane with destruction of microtriches. Plerocercoid scolices remained intact following in vitro dissolution of the body, but the bothria were not everted. Plerocercoid scolices obtained by in vivo body dissolution 5–6 h after surgical implantation into the small intestine of cats had begun differentiation as evidenced by elongation of the scolex tissue, thus forming a neck region, and eversion of the bothria.
Chemical modifications of amino groups of trypsin.

Abstract Reactivity of amino groups of chromatographically homogenious β-trypsin was studied by chemical modification. Guanidination by 1-amidinyl-3, 5-dimethyl pyrazole nitrate led to modification of 10 out of 14 lysyl residues per molecule of trypsin. The guanidinating reagent was found to be a competitive inhibitor of trypsin. Extent of acetamidination by methyl acetimidate hydrochloride was affected by pH, temperature and the presence of various competitive inhibitors. All 14 ϵ-amino groups of lysyl residues could be acetamidinated in the presence of the competitive inhibitors at pH 9.5 and 25° without loss of enzyme activity. When 11 or more lysyl residues are modified by acetamidination, the enzyme is stable against autolysis in the absence of Ca ++ . The enzyme with 10 of its 14 lysyl residues guanidinated loses its enzyme activity by autolysis at neutral pH at a rate comparable with unmodified enzyme.
Changed Lyotropic Liquid Crystalline Structure Due to Polymerization of the Amphiphilic Component

Optical patterns in polarized light and x-ray reflections in the low-angle region were used to detect a shift from one liquid crystalline structure to another during polymerization. The polymerization took place in a Iotropic liquid crystal of water and sodium undecenoate, with a structure consisting of cylinders in a two-dimensional hexagonal close packing. After polymerization, a lamellar liquid crystalline structure was obtained.
SNAKES EATING MORE THAN THEIR TAILS

![Figure][1] I'm sure we've all had the unfortunate experience of grossly overindulging at the dinner table. However, surely none of us has faced the sorts of dietary challenges confronted by ophiophagous snakes - those that consume other snakes as prey. Putting potential issues of