cssi/SciSciGPT-SciSciNet huggingface dataset:
Calcium-Mediated Biophysical Binding of Cryptosporidium parvum Oocysts to Surfaces Is Sensitive to Oocyst Age

Cryptosporidium parvum causes potentially life-threatening gastrointestinal disease in humans and may not be effectively removed from drinking water via conventional methods. Prior research has shown that environmental biofilms immobilize oocysts from the water column, but the biophysical mechanisms driving this attraction are still under investigation. This study investigates the affinity of C. parvum oocysts to silanized surfaces. Surfaces were prepared with hydroxyl, amine, and carboxyl moieties. Binding forces between the oocysts and these engineered substrates were analyzed, with and without divalent ions, using atomic force microscopy. Binding forces were measured over several weeks to investigate the influence of age on adhesion. C. parvum oocysts bind most strongly to carboxylic acid functional groups, with rupture forces greater than that required to break noncovalent molecular bonds, regardless of oocyst age. This adhesion is shown to be due to divalent cation bridging mechanisms. In addition, the binding strength increases over a 5-week period as the oocysts age, followed by a decrease in the binding strength, which may be related to structural or biochemical changes in the outer wall-bound glycosylated proteins. This study sheds new light on the biochemical parameters that influence C. parvum oocyst binding to surfaces. Increased understanding of how age and water chemistry influence the binding strength of oocysts may inform future developments in environmental detection and drinking water treatment, such as with the development of oocyst-specific sensors that allow for more frequent tracking of oocysts in the environment.IMPORTANCE The mechanisms by which pathogens bind to surfaces are of interest to a wide variety of scientific communities, as these mechanisms drive infectivity, fate, and transport of the pathogenic organisms. This study begins to reveal the mechanism of direct binding of Cryptosporidium parvum to surfaces containing both carboxylic acid and amine moieties, in an attempt to understand how much of the binding ability is due to long-range electrostatic forces versus other mechanisms (specific or nonspecific) of bonding. In addition to improving the scientific understanding of fate and transport of oocysts, an expanded understanding of the binding mechanisms may aid in the development of new tools and sensors designed to detect and track oocysts in waterways. Furthermore, the methods used to examine binding in this study could be translated to other waterborne pathogens of interest.
Deciding To Stay: A Study in Hospitality Managerial Grit:

Contributing to a relatively new stream of literature connecting grit to organizational retention, this research note examined how internal employability perceptions interacted with a manager’s gri...
Linear Transformations and Matrices

In order to compare different mathematical systems of the same type, it is essential to study the functions from one system to another which preserve the operations of the system. Thus in calculus we study functions f which preserve the limit operation: if \(\mathop {\lim }\limits_{i \to \infty } {x_i} = x\), then \(\mathop {\lim }\limits_{i \to \infty } f({x_i}) = f(x)\). These are the continuous functions. For vector spaces, we investigate functions that preserve the vector space operations of addition and scalar multiplication. These are the linear transformations. In this chapter we develop the language of linear transformations and the connection between linear transformations and matrices. Deeper results about linear transformations appear later.
An 11-Month-Old With Vomiting, Altered Mental Status, and Hypoventilation

Abstract Vomiting is a common pediatric complaint seen frequently in both pediatric and general emergency departments. Obstructive causes of vomiting are rare outside of the newborn period compared to more benign causes such as viral gastroenteritis. Timely recognition of these rarer causes of obstruction is essential for optimal care. This case highlights a severe presentation of chronic isolated vomiting caused by obstruction. It serves as a strong reminder to emergency care providers that obstruction can occur outside of the newborn period and, if unrecognized, can result in significant morbidity.
Debt Concordance and Relationship Quality: A Couple-Level Analysis

Despite a large literature on household finances and relationship quality, little is known about the degree of couple-level agreement on finances and its association with relationship outcomes. This study examines the relationship between financial concordance on household-level consumer debt and relationship quality, and the strength of the association after accounting for couple-level financial management practices. We apply hierarchical linear modeling (HLM) to couple-level data from a sample of married and cohabiting couples with children (435 couples, 870 respondents) from the Marital and Relationship Survey (MARS) and find that concordance on total household credit card debt is common but not the norm, with 55% of couples agreeing on their outstanding debt amount within our sample. Debt concordant couples have greater relationship satisfaction even after accounting for the outstanding debt amount, financial management practices such as income pooling, and joint purchase decisions, as well as relationship characteristics like their marital status, relationship duration, and the number of children in the household. We also find that disagreements related to financial issues attenuate the debt concordance and relationship quality association. Our results highlight the importance of including objective measures of household finance when assessing relationship quality.
The cognitive challenges of effective teaching

The authors describe a research-based conceptual framework of how students learn that can guide the design, implementation, and troubleshooting of teaching practice. The framework consists of nine ...
CT assessment of the left atrial appendage post-transcatheter occlusion - A systematic review and meta analysis.

Abstract Background Transesophageal echocardiography (TEE) is the standard imaging modality used to assess the left atrial appendage (LAA) after transcatheter device occlusion. Cardiac computed tomography angiography (CCTA) offers an alternative non-invasive modality in these patients. We aimed to conduct a comparison of the two modalities. Methods We performed a comprehensive systematic review of the current literature pertaining to CCTA to establish its usefulness during follow-up for patients undergoing LAA device closure. Studies that reported the prevalence of inadequate LAA closure on both CCTA and TEE were further evaluated in a meta-analysis. 19 studies were used in the systematic review, and six studies were used in the meta-analysis. Results The use of CCTA was associated with a higher likelihood of detecting LAA patency than the use of TEE (OR, 2.79, 95% CI 1.34–5.80, p ​= ​0.006, I2 ​= ​70.4%). There was no significant difference in the prevalence of peridevice gap ≥5 ​mm (OR, 3.04, 95% CI 0.70–13.17, p ​= ​0.13, I2 ​= ​0%) between the two modalities. Studies that reported LAA assessment in early and delayed phase techniques detected a 25%–50% higher prevalence of LAA patency on the delayed imaging. Conclusion CCTA can be used as an alternative to TEE for LAA assessment post occlusion. Standardized CCTA acquisition and interpretation protocols should be developed for clinical practice.
OpenMRS as a global good: Impact, opportunities, challenges, and lessons learned from fifteen years of implementation

Abstract Introduction OpenMRS is an open source medical record system that was first released in 2004. This research study analyzed OpenMRS implementations by conducting a survey of implementers and by reviewing publicly available data reported to the OpenMRS Community to learn about the utilization and impact of OpenMRS over the past 15 years. Methods Data about the use of OpenMRS were collected by conducting a survey of OpenMRS implementers that included both quantitative and qualitative questions. Data were also gathered from the OpenMRS community-hosted Atlas website and the OpenMRS Community Annual report to arrive at a comprehensive view of OpenMRS implementations. Results OpenMRS has been implemented in over 62 countries worldwide (Community Annual report). The survey was responded to by 16 organizations with projects spanning 16 countries, which were launched over 15 years (2004–2019). Fourteen of these sites reported a total of 1,436,357 patients; 4,248,248 visits; 18,028,204 encounters; 312,068,205 observations; and 5088 users, of which 3933 were health providers, recorded in the system database. Implementers reported a positive impact from implementing OpenMRS in streamlining operational processes for healthcare delivery; improved interoperability; improved reporting; improved availability and quality of data for decision making, advocacy, and research; and, improvement in the quality of healthcare delivery. Key challenges in implementing OpenMRS included finding skilled technical staff; acceptability of electronic health records by clinical staff; poor training provided to staff when transitioning from a paper-based to an electronic system; technical challenges, including infrastructure availability (computers, servers, equipment, connectivity, power); missing clinical/programmatic functionality in OpenMRS; poor documentation; and, difficulties faced when contributing code to the open source project. Conclusion OpenMRS has a broad reach globally in a variety of settings. Organizations have reported a positive impact on health care delivery after implementing OpenMRS. Several risks and challenges were identified by implementers that need to be addressed to deliver successful implementations. Continued investment in the development of OpenMRS is needed to sustain and scale its impact.
Impact of dialysis in patients undergoing bioprosthetic aortic valve replacement.

OBJECTIVES To determine the incidence of bioprosthetic structural valve deterioration in dialysis patients undergoing aortic valve replacement compared to that in patients without dialysis. METHODS This single-centre retrospective observational study included 1159 patients who underwent aortic valve replacement using bioprosthetic valves for aortic stenosis and/or regurgitation at our institution between 2007 and 2017 [patients with dialysis (group D, n = 134, 12%) or without dialysis (group N, n = 1025, 88%)]. To adjust for potential differences between groups in terms of initial preoperative characteristics or selection bias, a propensity score analysis was conducted. The final sample that was used in the comparison included 258 patients, as follows: 129 patients with dialysis (group D) and 129 patients without dialysis (group N). The cumulative incidences of all-cause death, cardiac death and moderate or severe structural valve deterioration were estimated using the Kaplan-Meier method. RESULTS Operative mortality was significantly higher in group D than group N (9% vs 0%, P = 0.001). Kaplan-Meier analysis revealed that in group D, the incidence was significantly higher for all-cause death (P < 0.001, 50% vs 18% at 5 years), cardiac death (P = 0.001, 18% vs 5% at 5 years) and moderate or severe structural valve deterioration (P < 0.001, 29% vs 5% at 5 years) compared with group N. CONCLUSIONS The incidence of structural valve deterioration in dialysis patients undergoing aortic valve replacement was higher than that in patients without dialysis. Bioprosthetic valves should be carefully selected in dialysis patients undergoing aortic valve replacement.
Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Abstract. The Mid-Pleistocene Transition (MPT) is a widely recognized global climate shift occurring between approximately 1,250 to 700 ka. At this time, Earth's climate underwent a major transition from dominant 40 kyr glacial-interglacial cycles to quasi-100 kyr cycles. The cause of the MPT remains a puzzling aspect of Pleistocene climate. Presently, there are few, if any, continuous MPT records from the Arctic yet understanding the role and response of the high latitudes to the MPT is required to better evaluate the causes of this climatic shift. Here, we present new continental biomarker records of temperature and vegetation spanning 1,142 to 752 ka from Lake El'gygytgyn (Far East Russia). We reconstruct warm-season temperature variations across the MPT based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) using the MBTʹ5ME proxy. The new Arctic temperature record does not display an overall cooling trend during the MPT but does exhibit strong glacial-interglacial cyclicity. Spectral analysis demonstrates persistent obliquity and precession pacing over the study interval and reveals substantial sub-orbital temperature variations at ~900 kyr during the first “skipped” interglacial. Interestingly, Marine Isotope Stage (MIS) 31, which is widely recognized as a particularly warm interglacial, does not exhibit exceptional warmth at Lake El'gygytgyn. Instead, we find that MIS 29, 27 and 21 were as warm or warmer than MIS 31. In particular, MIS 21 (~870 to 820 ka) stands out as an especially warm and long interglacial in the continental Arctic while MIS 25 is a notably cold interglacial. Throughout the MPT, Lake El'gygytgyn pollen data exhibits a long-term drying trend, with a shift to an increasingly open landscape noted after around 900 ka (Zhao et al., 2018), which is also reflected in our higher plant leaf wax (n-alkane) distributions. Although the mechanisms driving the MPT remain a matter of debate, our new climate records from the continental Arctic exhibit some similarities to changes noted around the North Pacific region. Overall, the new organic geochemical data from Lake El'gygytgyn contribute to expanding our knowledge of the high-latitude response to the MPT.
The Event-Free Fragment

This chapter concludes Part One of the book, and implements the major conclusions of the preceding chapters in a formal fragment of English. These conclusions form the starting assumptions for Part Two, which expands on them to account for a wider range of semantic phenomena than those considered so far. The fragment is intended to provide a way to pause and take stock, organizing our previous discussion into a single, coherent perspective which may be compared with the revised view developed in Part Two.
The Role of Subnivean Access in Winter Habitat Selection of Marten in Yellowstone National Park

This research project has two primary goals. The first is to determine home range spatial dynamics of marten (Maxes americana) in Yellowstone relative to habitat type. Results of this analysis will aid in the understanding of marten habitat selection. The study's second goal is aimed at identifying the habitat variables that influence subnivean access. A proximate factor analysis of subnivean access behavior will be conducted to determine the components that make old growth suitable for marten. Results from both objectives will allow assessment of the effects of the 1988 fires in Yellowstone on marten habitat.
Effect of handoff skills training for students during the medicine clerkship: a quasi-randomized Study

Continuity is critical for safe patient care and its absence is associated with adverse outcomes. Continuity requires handoffs between physicians, but most published studies of educational interventions to improve handoffs have focused primarily on residents, despite interns expected to being proficient. The AAMC core entrustable activities for graduating medical students includes handoffs as a milestone, but no controlled studies with students have assessed the impact of training in handoff skills. The purpose of this study was to assess the impact of an educational intervention to improve third-year medical student handoff skills, the durability of learned skills into the fourth year, and the transfer of skills from the simulated setting to the clinical environment. Trained evaluators used standardized patient cases and an observation tool to assess verbal handoff skills immediately post intervention and during the student’s fourth-year acting internship. Students were also observed doing real time sign-outs during their acting internship. Evaluators assessed untrained control students using a standardized case and performing a real-time sign-out. Intervention students mean score demonstrated improvement in handoff skills immediately after the workshop (2.6–3.8; p < 0.0001) that persisted into their fourth year acting internship when compared to baseline performance (3.9–3.5; p = 0.06) and to untrained control students (3.5 vs. 2.5; p < 0.001, d = 1.2). Intervention students evaluated in the clinical setting also scored higher than control students when assessed doing real-time handoffs (3.8 vs. 3.3; p = 0.032, d = 0.71). These findings should be useful to others considering introducing handoff teaching in the undergraduate medical curriculum in preparation for post-graduate medical training. Trial Registration Number NCT02217241.
Infinity-Norm Optimization with a Stable Controller

The stability of a feedback system with an open-loop stable controller is discussed, and an optimality condition in the infinity norm sense is derived in the MIMO case.
Outer membrane of Salmonella typhimurium: Identification of proteins exposed on cell surface

Abstract Proteins exposed on the outer surface of the outer membrane of Salmonella typhimurium were identified by reacting intact cells with a covalent labeling reagent. Since the outer membrane permitted the free diffusion of small hydrophilic molecules, we used a macromolecular reagent, CNBr-activated dextran, as the non-penetrating labeling agent. We also used a mutant producing a lipopolysaccharide with a very short (i.e. hexasaccharide) carbohydrate chain, in order to avoid steric hindrance by the carbohydrates on membrane surface. Results showed that out of the four “major” proteins of molecular weight around 35 000, three were exposed, and that at least six other proteins were also exposed on cell surface. Only two or three outer membrane proteins consistently did not react with the reagent in intact cells.
Spermicidal actions of extracts and compounds from Phytolacca dodecandra

Abstract The crude saponins from three plants, four purified saponins, and two synthetic derivatives were tested for spermicidal activity by means of an in vitro incubation procedure. The crude saponins and two purified saponins derived from Phytolacca dodecandra were found to have potent spermicidal activity. The most active compound tested against human sperm was lemmatoxin, a trisaccharide of oleanolic acid. Based on ED50 values obtained in our test system, the crude saponin preparation from P. dodecandra and lemmatoxin possessed nearly three times the spermicidal activities of a synthetic detergent currently used as a spermicidal agent. Biological activity could not be accounted for on the basis of surface activity.
In-Game Peer Performance Assessment Role That Fosters Metacognitive Agility and Reflection

In this paper we describe the development of a method and system for training metacognitive agility (self-awareness and self-regulated learning) in serious games applications. We introduce a unique design that features a novel role for real-time, in-game peer performance assessment and feedback to encourage user reflection and self-explanation. This approach has been implemented in two serious games currently in use today whose focus is intercultural competence and intercultural sensitivity education.
Multimodal nociceptive mechanisms underlying chronic pelvic pain.

Objective We sought to evaluate candidate mechanisms underlying the pelvic floor dysfunction in women with chronic pelvic pain (CPP) and/or painful bladder syndrome (PBS)/interstitial cystitis. Notably, prior studies have not consistently controlled for potential confounding by psychological or anatomical factors. Study Design As part of a larger study on pelvic floor pain dysfunction and bladder pain sensitivity, we compared a measure of mechanical pain sensitivity, pressure pain thresholds (PPTs), between women with pelvic pain and pain-free controls. We also assessed a novel pain measure using degree and duration of postexam pain aftersensation, and conducted structural and functional assessments of the pelvic floor to account for any potential confounding. Phenotypic specificity of pelvic floor measures was assessed with receiver operator characteristic curves adjusted for prevalence. Results A total of 23 women with CPP, 23 women with PBS, and 42 pain-free controls completed the study. Women with CPP or PBS exhibited enhanced pain sensitivity with lower PPTs (1.18 [interquartile range, 0.87–1.41] kg/cm 2 ) than pain-free participants (1.48 [1.11-1.76] kg/cm 2 ; P P P 2 , 41-51; P Conclusion Both experimental assessment of pelvic floor pain thresholds and measurement of sustained pain are independently associated with pelvic pain phenotypes. These findings suggest systematic clinical assessment of the time course of provoked pain symptoms, which occurs over seconds for mechanical pain thresholds vs minutes for aftersensation pain, would be helpful in identifying the fundamental mechanisms of pelvic floor pain. Longitudinal studies of therapies differentially targeting these discrete mechanisms are needed to confirm their clinical significance.
Blood Tests for the Detection of Thrombosis

Assays are available that allow the careful and wary investigator to use blood samples to derive useful information about hemostatic system activity. In practice the validity of the data will depend in very large part on the care which is taken in sample collection and processing. The particular system being studied profoundly influences the way in which the study should be performed. The details of the interacting issues are not yet resolved, and can only be dealt with as caveats. Finally and most importantly, these assays can not and should not be used to make the diagnosis of thrombosis. We believe that in general their use should be restricted to studies of pathophysiology. They are tools of exquisite sensitivity and specificity that allow us to probe the thrombotic process, and with care and imagination perhaps thrombogenesis itself.
Castorbeans: A New Oil Crop For Mechanized Production

Publisher Summary The castorbean plant, Ricinus communis L., has been of utilitarian and ornamental value to man. A modern use of castor oil is in the production of sebacic acid, involved in manufacturing certain plastics, nylon bristle, and synthetic lubricants for jet aircraft. Other uses are in manufacturing all-purpose greases, hydraulic fluids, artificial leather, pharmaceuticals, soap, printing ink, special low-temperature lubricants and flexible coatings, and fast-drying oils for paints and varnishes. Even before the development of the newest uses for castor oil, interest in domestic production was stimulated by war needs. During World War I, castor oil was used as a lubricant for airplane engines. As these examples attest, castor oil is one of the most versatile of the vegetable oils, which is capable of several kinds of chemical transformations.
Actuation in perception: Character classification in engineering drawings

We propose a novel approach to 2D character recognition by incorporating actuation data into the shape representation. Sensorimotor data is analyzed in terms of actuation sequences which generate the data. We illustrate the use of Wreath Products (WPs) to represent robot sensorimotor experience in a way that ties together perception and actuation. WPs naturally represent not only the Euclidean symmetries possessed by an object, but also the sequence of actuations used to generate those. Two distinct approaches using actuation signals to represent shape are compared: (1) the Kullback-Leibler measure is applied to histograms of translation symmetries in the shape, and (2) a distance metric is defined on pure actuation signals. Experimental results show that these methods achieve excellent classification rates (99 %) on text extracted from scanned images of engineering drawings for the top five hypotheses.
Rural Settlement Structure and African Development.

Rural Settlement Structure and African Development. Marilyn Silberfein. ed. Dunmore, PA: Harper Collins, 1998. 338 pp.
Disappearance rate of normal bactericidins in irradiated mice.

X-irradiated CF-1 mice lacking normal serum bactericidal activity for Escherichia coli were injected intravenously with highly bactericidal mouse serum. Passively transferred bactericidins were lost so rapidly from the circulating blood as to be undetectable 20 to 30 minutes later. Following 2 intravenous injections 30 minutes apart, bactericidins disappeared almost as quickly as after a single injection. The disappearance rates of normal bactericidins and immune hemagglutinins were compared under identical experimental conditions by injecting a mouse antiserum to sheep cells which was also bactericidal. The half- disappearance time of sheep cell agglutinins in mice was approximately 2 days, that of normal bactericidins, only a few minutes.
Electrophysiological Characterization of Mitochondrial Uncoupling Protein 1

Uncoupling proteins (UCP1- UCP5) are integral transport proteins of the inner mitochondrial membrane (IMM). They mediate transmembrane ion leak, thus dissipating the electrochemical proton gradient across the IMM and uncoupling mitochondrial respiration and ATP synthesis. UCPs are involved in thermogenesis, reducing fat deposition, and attenuating reactive oxygen species production by mitochondria to protect the cell against oxidative damage and ageing. The mechanism of ion conductance of UCPs has long remained elusive due to the lack of direct methods for measuring ion currents produced by them. To resolve this problem, we applied the patch-clamp technique to the whole inner membrane of mitochondria from the brown adipose tissue to identify and characterize currents produced by the family's founding member, UCP1. In our experiments, both the cytoplasmic and matrix faces of the IMM were exposed to solutions that did not contain any ions normally permeable through ion channels or transporters, except for H+ and OH-. Under these conditions, we identified a current that showed all signature properties of UCP1: it was strongly potentiated by micromolar concentrations of unsaturated fatty acids, inhibited by removing endogenous membrane fatty acids with bovine serum albumin, and blocked by micromolar concentrations of purine nucleotides. Moreover, the current was absent in the IMM of the kidney COS-7 cells, in agreement with the fact that UCP1 is specifically expressed in the brown adipose tissue. The transport molecule mediating this current was activated by membrane depolarization and showed robust tail currents upon return to the negative potentials. In a symmetrical pH 5.0 solution the current amplitude was negligible as compared to a symmetrical pH 8.0 solution, suggesting that the current was carried by OH- but not H+. Our results indicate that UCP1 is a low-conductance OH- channel weakly activated by membrane depolarization.
Measurement of spin-lattice relaxation times and kinetic rate constants in rat muscle using progressive partial saturation and steady-state saturation transfer

31P spin-lattice relaxation times (T1) of metabolites in rat calf muscle at 1.9 Tesla and the forward rate through the creatine kinase (CK) reaction have been measured using a new method based on modeling progressive saturation explicitly incorporating the effect of chemical exchange. In a separate series of experiments, we compared our method with inversion recovery both in vitro and in vivo, finding agreement between the techniques. We found that the T1 values of phosphocreatine (PCr) (6.6 ± 0.3 s), γ-ATP (2.6 ± 0.6 s), α-ATP (2.4 ± 0.4 s) and β-ATP (2.2 ± 0.2 s) are unchanged by stimulation of sufficient intensity to induce a 32% drop in PCr level. The errors in T1 values which arise when chemical exchange is neglected are calculated. These are found to be on the order of 20% for PCr and 30–50% for γ-ATP under typical conditions. Use of longer repetition times results in larger errors in measured values of T1. This source of error can be effectively eliminated by use of sufficiently short repetition times. We found that the rate constant of the forward CK reaction was increased 60% by stimulation, from 0.20 ± 0.03 s−1 to 0.32 ± 0.03 s−1, but that the phosphorus flux did not change.
Bbs and bullets: the impact of dietary factors on blood pressure.

An impressive body of evidence supports the concept that multiple dietary factors affect blood pressure.1 Typically, the blood pressure response to manipulation of a single nutrient is modest and heterogeneous; that is, the response can vary by baseline nutrient intake, baseline blood pressure, demographic factors, genetic polymorphisms, and other host factors. In this setting, the search for new dietary factors is fraught with hazards. The risk of false-negative results is high, especially in underpowered clinical trials, as is the risk of false-positive results, especially in observational studies that must deal with the treacherous issue of confounding. In addition to sodium intake, potassium intake, weight, and alcohol consumption, other diet-related factors likely affect blood pressure. For instance, preliminary evidence suggests that an increased intake of protein2 and of monounsaturated fats3 might also reduce blood pressure. Will the likely impact of new factors be substantial (a “bullet”) or modest (a “BB”)? Results from the Dietary Approaches to Stop Hypertension (DASH) trial have raised the hope that bullets are plausible.4 …
Platelet reactivity and nonresponse to dual antiplatelet therapy: a review.

Clopidogrel is a second-generation thienopyridine that irreversibly inhibits the P2Y12 adenosine diphosphate (ADP) receptor on platelets, preventing platelet aggregation. As early as 2003, research...
Analysis of Support Apparatus for Flexural Load-Deflection Testing: Minimizing Bias Caused by Arching Forces

It is in the best interests of standards development that bias and inter-laboratory variability be minimized in the reporting of test results. However, the apparatus sections of flexural test standards, such as ASTM C78, C1399, C1550, and C1609, may not adequately address important issues raised in this study that could adversely affect test results. Specifically, current standards specifications fail to address arching forces and effective span control. The mechanics of commonly applied journal-bearing-type support designs are analyzed and compared to an alternative ball or needle-bearing-type support design. The analysis demonstrates that significant bias can be introduced as a direct consequence of the mechanics that is the nature of journal-bearing-type supports. The analysis applies equally well to flexural tests involving small deformations of portland cement concrete or similar brittle materials, as it does to tests that are carried out involving relatively large deformations, such as with fiber-reinforced concrete.
A mutation distal to the messenger RNA endpoint reduces transcription termination in the tryptophan operon in Escherichia coli.

Abstract Mutations abolishing transcription termination were isolated in the region in which transcription of the trytophan ( trp ) operon normally terminates. This region of the wild type and mutant strains was incorporated into the genome of bacteriophage λ, and phage DNA was analyzed by digestion with restriction endonucleases. The 15 independently isolated mutations were shown to be deletions ranging in extent from 200 to 1000 base-pairs, which lie past the end of the trp operon. One of the mutations causing readthrough into distal lactose ( lac ) genes deletes 185 base-pairs, beginning 60 nucleotides beyond the point where messenger RNA synthesis ceases in vivo . We infer that the nature of sequences some distance beyond the point of transcription termination can influence the extent of termination at that site.
Increased cyclic GMP levels associated with contraction in muscle fibres of the giant barnacle.

CYCLIC GMP has been implicated as an intracellular second messenger in a variety of systems. In particular, a number of hormones and neurotransmitters have been shown to raise cellular cyclic GMP levels in vitro1–9. In many of these systems, however, Ca2+ entry seems to be responsible both for the physiological effect of the hormone and for the hormone-stimulated increase in cyclic GMP (refs 4–9). We have investigated the relationship between calcium and cyclic GMP levels in muscles of the giant barnacle Balanus nubilus. This preparation has a number of advantages. Within fairly narrow limits intracellular free calcium levels in the resting muscle are known10. The depolarisation-induced increase in free calcium, and the resulting activation of contraction, have also been extensively documented10,11. In addition, the depolarisation-induced changes in intracellular free calcium can be easily manipulated because the extracellular fluid is the apparent source of the calcium which couples excitation to contraction12. We report here that either KC1 depolarisation or nerve stimulation increases the cyclic GMP content of barnacle muscle. This increase seems to be associated with Ca2+ entry rather than with a neurotransmitter–receptor interaction per se. This is the first report of an increase in cyclic GMP associated with contractile activity in cross-striated muscle.
Optimal printed wiring board design for high I/O density chip size packages

This paper addresses the issues involved in the design of high‐density boards for high‐density chip scale packages. An analytical model is developed to calculate the number of I/Os accommodated by the printed wiring board. The model is placed under constraints of package area, package I/O pitch, number of lanes per channel, PWB device feature sizes (I/O, via pad, signal traces), number of routing layers on board and the partition of routing regions on each level. The model is utilized to study the precise impact of number of routing layers and device feature size on the I/O density of PCB. The scheme for optimally partitioning each layer to achieve maximum I/O density is discussed. Specific guidelines are provided pertaining to the usage of higher board layers and/or reduced device feature sizes to design high‐density boards for future electronic products.
Enthalpies of hydrogenation of the isomers of n-hexene

Abstract Taking results derived from enthalpies of hydration as an arguably valid standard, enthalpies of isomerization of two of the five n-hexanes are more accurately reproduced by hydrogen calorimetry than by combustion calorimetry. The present work does not support the notion that hydrogen thermochemistry is inherently inaccurate because of kinetic lag.
Improving Stability Margins of Rotational Vibration Feed-Forward Compensator

This work focuses on stability analysis and design for rotational vibration feed-forward (RVFF) compensator for hard disk drive (HDD) servo control system. We consider the effect of the coupling phenomenon between the voice coil motor (VCM) control current and the rotational vibration acceleration measurements. The coupling creates an undesirable feedback loop, which affects stability of the RVFF compensator as well as it limits the achievable system performance. In this work we present a method for the parasitic coupling mitigation. This method uses self-induced coupling vibration prediction to remove the coupling signal component from the rotational vibration (RV) acceleration measurements. We consider linear time invariant coupling estimator, which is more appealing for analysis in frequency domain, as well as its nonlinear adaptive version, which is more suitable for robust operation in uncertain environment.Copyright © 2014 by ASME
RECIRCULATION OF LYMPHOCYTES

Abstract : The long-lived small lymphocyte population of the rat includes approximately 90 per cent of the cells which appear in thoracic duct lymph. About two-thirds of the small lymphocytes in blood are long-lived. These long-lived cells are produced at a rate proportional to body growth and recirculate from blood to lymph. Althouohtthough a major percentage of the small lymphocytes in lymph nodes and a smaller percentage of those in spleen are of the long-lived variety, the thymus may be their primary source of origin. The small lymphocytes in the bone marrow, approximately 95 per cent of those in the thymus and a major percentage of those in the spleen are short lived (five days or less). Evidence is presented which suggests that the long-lived lymphocyte plays an active role in immune response mechanisms. (Author)
Effect of PCB and DES on rat monoamine oxidase, acetylcholinesterase, testosterone, and estradiol ontogeny.

Diethylstilbestrol (DES) and polychlorinated biphenyl (PCB) have been documented as potentially hazardous environmental agents. In utero exposure to DES produces human vaginal adenocarcinoma, male reproductive tract lesions in mice, and has been correlated with personality changes in human males. PCB (Kanechlor) was found to be the major toxin in the {open_quotes}Yusho{close_quotes} rice oil poisoning in Japan in 1968. Other investigators have shown in rats that PCB (Arochlor) causes liver adenofibrosis, thyroid dysfunction, atypical mitochondria, and dilation of both smooth and rough endoplasmic reticulum. Matthews et al. (1978) also reported that 4, 4{prime} chlorinated biphenyl was the most potent inducer of monooxygenases, irrespective of chlorination at other sites. Although these compounds have been studied extensively in mammals, there is a paucity of data examining their effects when non-fetotoxic amounts are administered chronically and orally during gestation. The present study is part of a larger effort designed to establish a protocol for testing the developmental effects of xenobiotics such as DES and PCB. Levels of acetylcholinesterase (AChE) were measured as an indicator of the integrity of nerve transmission in the central nervous system. Monoamine oxidase (MAO) is a marker for the outer mitochondrial membrane and is an important amine metabolizing enzyme. Testosteronemore » and estradiol are important sex steroids in mammals, and effects upon levels of the two hormones may signal anomalies in development of sex characteristics. 35 refs., 3 figs., 1 tab.« less
Quantifying the Pinatubo volcanic signal in south polar snow

Recent snow and firn core samples from South Pole contain increased sulfate (SO42−) concentrations during 1992–1994 as a result of the June 1991 Pinatubo eruption and the August 1991 Cerro Hudson eruption in Chile. Traces of Pinatubo tephra (volcanic ash) were identified in the 1993 and 1994 snow layers, supporting the conclusion that increased SO42− in 1993–1994 is from the Pinatubo eruption. Although the Pinatubo eruption preceded Hudson, its SO42− signal in south polar snow follows and is resolved from that of Hudson. The deposition of the Pinatubo SO42− aerosol was delayed due to the long transport to the high southern latitudes and its initial existence at high altitudes in the Antarctic atmosphere. Multi-year, multi-site sampling demonstrates that the volcanic signals are well preserved and spatially consistent. Measurements on 2 firn cores show that the South Pole SO SO42− flux from Pinatubo is 10.9±1.2 kg km−2 over 2.2 years, while the Hudson flux is 3.2±0.6 kg km−2 in 1.1 years. These results, when combined with satellite-determined Pinatubo sulfur dioxide (SO2) emission, make it possible to link quantitatively the atmospheric aerosol mass loading from a low-latitude volcanic eruption to its signal in polar ice cores.
Poly(aryl ether ketone) synthesis via competing SNAR and SRN1 reactions: 1. Polymers derived from 1,3-bis(p-chlorobenzoyl)benzene and 1,3-bis(p-fluorobenzoyl)benzene with hydroquinone and 4,4′-isopropylidenediphenol

Abstract Poly(aryl ether ketone)s were synthesized by the reaction of 1,3-(bischlorobenzoyl)benzene or the corresponding fluoro analogue with bisphenoxides derived from either hydroquinone or 4,4′-isopropylidenebiphenol (bisphenol-A). With the stronger nucleophile, obtained from bisphenol-A, and either of the dihalides, high molecular weight polymers are formed exclusively via a nucleophilic aromatic substitution (SNAR) reaction. A similar reaction leads to the formation of a high molecular weight polymer when the weaker nucleophile, derived from hydroquinone, is allowed to react with the bisfluoride. On the other hand, oligomeric products are obtained when the bischloride is treated with this weaker nucleophile. In this case, both SNAR and SRN1 (substitution, radical-nucleophilic, unimolecular) mechanisms are operative for the replacement of the chlorine atoms. The SRN1 pathway, which is responsible for the formation of oligomeric products, can be eliminated by the addition of a suitable radical scavenger. High molecular weight poly(aryl ether ketone) is then formed via the SNAR mechanism.
Terminal attractors for addressable memory in neural networks

A new type of attractors - terminal attractors - for an addressable memory in neural networks operating in continuous time is introduced. These attractors represent singular solutions of the dynamical system. They intersect (or envelope) the families of regular solutions while each regular solution approaches the terminal attractor in a finite time period. It is shown that terminal attractors can be incorporated into neural networks such that any desired set of these attractors with prescribed basins is provided by an appropriate selection of the weight matrix.
Heuristic approach to the artificial intelligence design challenge

We propose a heuristic approach to solve the AIAA design challenge problem. The procedure employs the repeated solution of knapsack problems with possibly changing coefficients to build a tour and to determine subsets of cities to be inserted or dropped. The local constraint and triangular inequality violations are taken care of in a "tour-arrangement" stage. Furthermore, general exchange routines for the traveling salesman problem are used to improve the tour. As for a given tour, we apply addition and replacement routines to satisfy the probability constraint.
Delayed Differentiation for Multiple Lifecycle Products

Modular design allows several generations of products to co-exist in the installed base as product designs change to take advantage of improved performance via modular upgrades. Use of a common base platform and modular design approach allows a firm to offer updates for improved performance and flexibility via remanufacturing when products have multiple lifecycles. However, as the product evolves through multiple lifecycles, the large pool of product variants leads to the curse of product proliferation. In practice, product proliferation causes high levels of line congestion and results in longer lead times, higher inventory levels, and lower levels of customer service. To offer insights into the product proliferation problem, the authors employ a delayed differentiation model in a multiple lifecycle context. The delayed differentiation model gives flexibility to balance trade-offs between disassembly and reassembly costs by adaptively changing the push-pull boundary. An adaptive, evolving push-pull boundary provides flexibility for a remanufacturing firm to meet changing customer demands. The delayed differentiation model includes both a mixed-integer linear program and an analytical investigation of the evolutionary nature of the push-pull boundary. Both field observations and experimental results show that the nature of product proliferation and changing demand structures play significant roles in the cost and flexibility of the evolving delayed differentiation system.
DIS next-generation protocol architecture

Several new architectural components are needed by distributed interactive simulation (DIS) to support new and expanding distributed interactive simulation applications. The elements defined include: organization of DIS protocols into groups to provide for basic interoperability and optional interoperability associated with different functional domains; a supporting message structure that is ore efficient and flexible than the one currently defined in the DIS standards; a data element dictionary to hold the definitions of the lowest order elements of information exchanged between simulation applications in a DIS exercise; and a protocol catalog to hold the definitions of the protocols used to exchange information between simulation applications in a DIS exercise.
DNA methylation and Sp1 binding determine the tissue-specific transcriptional activity of the mouse Abcc6 promoter

The gene encoding the ABCC6 protein, an ABC transporter of the multidrug resistance-associated protein (MRP), is mainly expressed in liver and kidney. Mutations in ABCC6 are responsible for the development of the pseudoxanthoma elasticum (PXE) phenotype. PXE is a recessive disease characterized by the calcification of elastic fibers resulting in dermal, vascular, and ocular clinical manifestations. The physiological function of ABCC6 and the rodent orthologs Abcc6 is unknown and their precise relationship to elastic fibers is only a matter of speculation. Despite several studies focused on the transcriptional regulation of ABCC6/Abcc6, the molecular signals conferring the tissue-specificity to the ABCC6/Abcc6 expression are not well defined. In this report, we determined the level of the mouse Abcc6 promoter methylation in tissues with low level of expression (tail extremity and skin), intermediate (kidney), and high level of expression (liver). We observed that high and moderate levels of methylation correlated with low levels of Abcc6 expression. Moreover, we determined that CpG methylation of the Abcc6 proximal promoter region was interfering with the binding of the Sp1 transcription factor thereby inhibiting Sp1-dependent transactivation. Thus, our data provide the first direct evidence that an epigenetic mechanism regulates the binding of transcription factor Sp1 to the proximal promoter and participates in the tissue-specific expression control of the mouse Abcc6 gene.
Multitime-scale singularly perturbed linear stochastic systems ∗

By applying diagonalization transformation, generalized variation of constants formula and theory of differential inequalities,the mean square convergence of solution process of a shingularly perturbed linear stochastic differential system of Ito-type is investigated. Moreover, slow and fast modes decomposition provides an auxiliary decoupled system whose solution processes are incorporated in approximating the solution processes of the original system
Static Posturography and Recurrence Quantification Reliably Detect Postural Instability

Postural instability is a primary symptom of advanced Parkinson's disease (PD). Falling, and restriction of activity due to postural instability have a major influence on the health and quality of life of individuals with PD. Presently, clinical measurement of postural stability in PD is crude. The purpose of the present study was to assess the ability of static posturography and a time-series analysis technique termed recurrence quantification analysis (RQA) to detect postural instability in PD (Hoehn and Yahr Stage 3 - participants with known postural instability). The results of analyses indicate that the postural sway of participants with PD was more variable than that of elderly, healthy controls. In addition, the spatiotemporal profile of postural sway for PD participants reflected greater regularity and stability. These results suggest that the novel combination of static posturography and RQA may be a suitable testing and evaluation method for detecting postural instability.