cssi/SciSciGPT-SciSciNet huggingface dataset:
Measurement of gastrointestinal motility in the GI laboratory

Abstract Current tests of gastric and small intestinal motor function provide relevant physiological information, but their clinical utility is controversial. This article reviews the current procedures, indications, significance, pitfalls, and guidelines for gastrointestinal motility measurements by scintigraphy, gastroduodenojejunal manometry, and surface electrogastrography in humans. Methods included review of literature and discussions in closed and open fora among investigators, including presentations for peer review at focused (Iowa City American Motility Society Symposium, December 1995) and national meetings (American Gastroenterological Association, May 1996, and American Motility Society, September 1996). The current tests are generally complementary; scintigraphy is typically the first test in the evaluation of gastric motor function and often confirms the clinical suspicion of dysmotility. Manometry identifies patterns suggestive of myopathy, neuropathy, or obstruction but may be most helpful when it shows entirely normal findings, because manometry helps in part to exclude dysmotility as a cause of symptoms. Electrogastrography may identify dysrhythmias or failure of signal power to increase postprandially; rhythm abnormalities may be independent of impaired emptying among dyspeptic patients. The best validated and clinically most significant results pertain to transit tests; manometry may contribute importantly to the diagnostic process; and the significance of electrogastrography remains to be fully elucidated. GASTROENTEROLOGY 1998;115:747-762
Isolation, primary structure, and synthesis of leucokinins V and VI: Myotropic peptides of Lleucophaea maderae☆

Abstract 1. Two additional octapeptides which stimulate the contractile activity of the cockroach hindgut have been isolated from head extracts of the cockroach, Leucophaea maderae . 2. A series of four high performance liquid-chromatographic (HPLC) fractionations yielded sufficient quantities of pure peptides for micro amino acid analysis and primary sequence determinations. The sequence determined for two peptides were: Gly-Ser-Gly-Phe-Ser-Ser-Trp-Gly-NH 2 and pGlu-Ser-Ser-Phe-His-Ser-Trp-Gly-NH 2 . These octapeptides were designated leucokinins V and VI (L-V, L-VI), respectively. 3. Minimum concentrations of natural L—V and L-VI required to produce a response from the isolated cockroach hindgut were 4.5 × and 4.9 × 10 −11 M, respectively. These concentrations were quite similar to the threshold concentrations observed for the synthetic products.
Have unions impeded growing wage dispersion among young workers

Wage inequality is examined for young males over the period 1980–1993. While wage inequality increased substantially for nonunion workers over this period, wage inequality increased only modestly for union workers. In part, this difference results from divergent trends in skill prices—returns to skill rose in the nonunion sector but contracted slightly in the union sector. In particular, returns to education increased sharply in the nonunion sector while remaining stagnant in the union sector. At least for young workers, these findings suggest that unions have been largely successful in resisting market pressures for greater wage inequality. We also uncover evidence suggesting that, as relative returns to education decline in the union sector, highly educated young workers become less likely to choose union employment.
Extended unambiguous range interferometry.

Phase measuring interferometers generally measure phase modulo 2π. We present a system which uses fringe contrast to help determine the absolute phase in the interference image within the limits of the coherence length of the illumination. This approach obviates the need for phase unwrapping and is unaffected by surface discontinuities or by data dropout. Since the phase is determined on a point-by-point basis, the processing could be pipelined. The system is set up on a microscope interferometer and produces surface profiles over an array of 512 × 512 points. The measurement range is related to the coherence length of the source and can easily be varied from 0.5 to 2.5 μm. The resolution is limited by the 8-bit quantization of the output.
Methane hydrate formation and an inward growing shell model in water-in-oil dispersions

Significant factors controlling gas hydrate growth in water and water-in-oil dispersions have been tested. In particular, the influence of shear rate, presence of oil, and thermodynamic driving force (represented by pressure supersaturation) on hydrate growth rates is included. Formation rates in water show some discrepancy compared to previous work, which is likely caused by differences in the apparatus geometries. A model is proposed for growth of hydrate in oil, in which a hydrate shell forms on a water droplet, followed by additional conversion of the water core to hydrate.
Yield and Germinability of Seed from Irrigated and Nonirrigated Early- and Late-Planted MG IV and V Soybean

Drought stress in the midsouthern USA reduces yield of soybean [Glycine max (L.) Merr.] planted in May and June and sometimes affects germination of harvested seed. Irrigation often increases yield, and may also increase seed germinability. Field experiments were conducted on Sharkey clay (Vertic Haplaquept, very-fine, montmorillonitic, termic) in 1992, 1993, and 1994 at Stoneville, MS. The objective was to determine the effects of earlier-than-normal (April) and normal (May) planting dates on yield and germinability of harvested seed of Maturity Group (MG) IV and V soybean cultivars grown in nonirrigated (NI) and furrow-irrigated (I) environs. In 1992, germination of seed of all cultivars harvested from the NI (14-73%) and (36-77%) 15 April plantings was lower than that of seed harvested from the 27 May plantings. In 1993 and 1994, germination of all harvested seed averaged more than 90%. Without irrigation, seed yield from the April plantings exceeded that from the May plantings every year. The difference was greatest in 1992 (3170 vs. 2190 kg ha- 1 and least in 1993 (1432 vs 1295 kg ha -1 ). In 1992, the 4195 kg ha -1 average yield with irrigation from the 15 April planting exceeded the 2979 kg ha -1 average yield from the 27 May planting. In 1994, yield of all irrigated cultivars in the 21 April planting equalled or exceeded the yield of the same cultivars planted on 13 May. Yields of MG V cultivars were equal to or greater than those of MG IV cultivars in both I and NI plantings in all years. These results demonstrate that April vs. normal May plantings of both MG IV and V cultivars can increase yields when grown with and without irrigation in the midsouthern USA.
Intelligent Tutors for Aviation Automation Mitigating the Problem!?1:

This paper describes a research program that addresses a variety of issues and problems in training pilots to fly modern, highly sophisticated aircraft First, the paper describes two intelligent tutors developed to teach two important aspects of aviation: a tutor that teaches management of the vertical dimension of the flight management system for pilots in transition training; and a tutor that teaches expert novices, that is, certified pilots, procedures not included in their transition training. Second, both tutors extend GT-ITACS (Georgia Tech-Intelligent Tutoring Architecture for Complex Systems), a computational development environment for intelligent tutors. In general, implementing instructional material in computational form is the most difficult step in developing effective computer-based instruction; this is particularly true for intelligent tutors Computational implementation is so difficult that implementing computer-based training is often cost and time prohibitive—explaining in part the smal...
Some Elementary Examples of Unirational Varieties Which are Not Rational

An outstanding problem in the algebraic geometry of varieties of dimension n ^ 3 over an algebraically closed field k has been whether there exist unirational varieties which are not rational. Here V is unirational if it has the equivalent properties: (a) there exists a rational surjective map / : V -> V, or, there exists an embedding k(V) V, or, there exists an isomorphism k(V) = k(Xv ...,1^). For n—\, these are equivalent (Liiroth's theorem). For n = 2 they are equivalent in characteristic 0 (Castelnuovo's theorem) or if the map / in (a) is assumed separable (Zariski's extension of Castelnuovo's theorem). In 1959 ([13]), Serre clarified classical work on this problem for n = 3. It has been generally accepted since then that none of the examples proposed by Fano or Roth had been correctly proved irrational. In the past year, two solutions of this problem have been found: Clemens and Griffiths ([6]) showed that all non-singular cubic hypersurfaces in P are irrational, and Iskovskikh and Manin ([16]) showed that all non-singular quartic hypersurfaces in P are irrational. Some are unirational (Segre ([11])). Both of these solutions are quite deep and it seems worth while to have an elementary example as well, even if our method applies to a very special kind of variety. Ramanujam suggested using torsion in H and this led us to the examples presented here. We construct varieties, of all dimensions n ^ 3 and all characteristics £> # 2, which are unirational and which have 2-torsion in H. With the present state of resolution of singularities, we can show that such a V cannot be rational if the characteristic is 0 or if the characteristic is not 2 and n = 3.
An Upper Bound Theorem for Rational Polytopes

The upper bound inequality[formula](0?i?d/2) is proved for the torich-vector of a rational convexd-dimensional polytope withnvertices. This gives nonlinear inequalities on flag vectors of rational polytopes.
Visual execution of assembly language programs

Students learning computer organization and assembly language programming often have difficulty understanding the relationship between hardware functions and software instructions. This paper describes how a software tool can help students understand the organization and use of the Motorola 68000 processor family. XSIM68K employs a graphical interface to enhance a traditional “black box” simulator so that students can observe first-hand the effect of a running program on registers, memory, and II0 devices. Multiple data representations allow the student to choose the most appropriate format for data entry and display, which reduces confusion and eliminates conversion mistakes.
Economic models are not evolutionary models

; Henrich et al. reject the "selfishness axiom" within a narrowly- defined economic model, and are premature in claiming that they have demonstrated cross-cultural variability in "selfishness" as defined in broader evolutionary theory. We also question whether a key experimental condition, anonymity, can be maintained in the small, cohesive, social groupings employed in the study.
Technical developments in MR angiography

Catheter-based multistation digital subtraction angiography (DSA) is regarded as the gold standard for the evaluation of vascular disease. The high incidence of morbidity associated with radiographic DSA has placed emphasis on developing noninvasive methods of determining whether surgical intervention is indicated. Invasiveness, costs, and morbidity indicate the need for less invasive diagnostic tools. Magnetic resonance angiography (MRA) is emerging as an adjunct and, in some cases, an alternative to DSA. The growth of MRA is the result of improvements in image acquisition strategies and magnetic resonance (MR) contrast agents. Contrast agent-enhanced MRA (CE MRA) examinations result in images with highspatial resolution and fewer artifacts and require less time to acquire than noncontrast methods. This article reports on recent technical developments in this emergent technology. Many of these acquisition strategies attempt to optimize the use of the first pass of the bolus of contrast agent. To do so, they coordinate image acquisition with arrival of the contrast agent in the targeted anatomy. This may be accomplished given prior knowledge of the transit time of the bolus from injection site to the image volume or by triggering the acquisition when arrival of the contrast is detected. Triggered acquisitions are performed either by pulse sequences, which automatically detect the inflow of contrast agent, or by fluoroscopicacquisitions,whicharetriggeredbyanoperator. CE MRAacquisitionsrelyonheavilyT1weighted, rapidimagesacquisition.Thesimplestwaytospeedup an acquisition is to reduce the repetition (TR). Recently, novel image reconstructions have been developed in which multicoil arrays share data to further reduce acquisition time. In addition, many groups are successfully using non-Cartesian k-space–based data acquisitions that sample k-space along spiral or radial trajectories. This article discusses some of the basic physics principles necessary to understand the limitations and challenges of CE MRA. A short technical description of some of the more recent technical advancements with several illustrative examples follows. The last section of this article describes currently available contrast agents and some agents that are in development or under review by the United States Food and Drug Administration.
SMC complexes in bacterial chromosome condensation and segregation

Bacterial chromosomes segregate via a partition apparatus that employs a score of specialized proteins. The SMC complexes play a crucial role in the chromosome partitioning process by organizing bacterial chromosomes through their ATP-dependent chromatin-compacting activity. Recent progress in the composition of these complexes and elucidation of their structural and enzymatic properties has advanced our comprehension of chromosome condensation and segregation mechanics in bacteria.
Diverticula of the bladder in children

Diverticula of the bladder in infants and children are common and occur when vesical mucosa protrudes through a congenital defect in the muscle wall. Most are primary. Diverticula secondary to obstruction or neurogenic dysfunction are not as common as was once thought. The majority of diverticula are asymptomatic but they can cause vesico-ureteral reflux, obstruction or residual urine. Diverticula also occur after bladder surgery and in association with some syndromes. Voiding cystourethrography is the most reliable method for detection.
The Rhesus Rhadinovirus CD200 Homologue Affects Immune Responses and Viral Loads during In Vivo Infection

Rhesus macaque rhadinovirus (RRV) is a gammaherpesvirus of rhesus macaque (RM) monkeys that is closely related to human herpesvirus 8 (HHV-8)/Kaposi's Sarcoma-associated herpesvirus (KSHV), and it is capable of inducing diseases in simian immunodeficiency virus (SIV)-infected RM that are similar to those seen in humans coinfected with HIV and HHV-8. Both HHV-8 and RRV encode viral CD200 (vCD200) molecules that are homologues of cellular CD200, a membrane glycoprotein that regulates immune responses and helps maintain immune homeostasis via interactions with the CD200 receptor (CD200R). Though the functions of RRV and HHV-8 vCD200 molecules have been examined in vitro, the precise roles that these viral proteins play during in vivo infection remain unknown. Thus, to address the contributions of RRV vCD200 to immune regulation and disease in vivo, we generated a form of RRV that lacked expression of vCD200 for use in infection studies in RM. Our data indicated that RRV vCD200 expression limits immune responses against RRV at early times postinfection and also impacts viral loads, but it does not appear to have significant effects on disease development. Further, examination of the distribution pattern of CD200R in RM indicated that this receptor is expressed on a majority of cells in peripheral blood mononuclear cells, including B and T cells, suggesting potentially wider regulatory capabilities for both vCD200 and CD200 that are not strictly limited to myeloid lineage cells. In addition, we also demonstrate that RRV infection affects CD200R expression levels in vivo, although vCD200 expression does not play a role in this phenomenon. IMPORTANCE Cellular CD200 and its receptor, CD200R, compose a pathway that is important in regulating immune responses and is known to play a role in a variety of human diseases. A number of pathogens have been found to modulate the CD200-CD200R pathway during infection, including human herpesvirus 8 (HHV-8), the causative agent of Kaposi's sarcoma and B cell neoplasms in AIDS patients, and a closely related primate virus, rhesus macaque rhadinovirus (RRV), which infects and induces disease in rhesus macaque monkeys. HHV-8 and RRV encode homologues of CD200, termed vCD200, which are thought to play a role in preventing immune responses against these viruses. However, neither molecule has been studied in an in vivo model of infection to address their actual contributions to immunoregulation and disease. Here we report findings from our studies in which we analyzed the properties of a mutant form of RRV that lacks vCD200 expression in infected rhesus macaques.
Thermal inactivation of tepary bean (Phaseolus acutifolius), soybean and lima bean protease inhibitors: effect of acidic and basic pH

Abstract Thermal stability of the protease inhibitor of tepary bean ( Phaseolus acutifolius ) was studied by comparing the antitryptic activities of a crude extract and the purified inhibitor (TBPI) to those of three purified protease inhibitors, soybean trypsin inhibitor (Kunitz; KSTI), soybean trypsin and chymotrypsin inhibitor (BBI) and lima bean trypsin inhibitor (LBTI). Three purified inhibitors, TBPI, BBI and LBTI, were found to be heat-stable when subjected to boiling (100 °C) at either neutral or acidic pH, or to autoclaving at neutral pH. The tepary bean crude extract and KSTI were found to be heat labile when boiled or autoclaved at neutral pH. At alkaline pH, all the purified protease inhibitors were heat labile, losing antitryptic activity rapidly upon heating to 100 °C. These data suggest that the trypsin inhibitor of TBPI is heat-stable, and similar to the Bowman–Birk family of inhibitors, and can be rapidly inactivated by heat under alkaline conditions.
Directions for Combustion Engine Aerosol Measurement in the 21st Century

The Coordinating Research Council convened two Real-Time PM Measurement Workshops in December 2008 and March 2009 to take an intensive look at the current status and future directions of combustion aerosol measurement. The purpose was to examine the implications of parallel rapid developments over the past decade in ambient aerosol science, engine aftertreatment technology, and aerosol measurement methodology, which provide benefits and challenges to the stakeholders in air quality management. The workshops were organized into sessions targeting key issues in ambient and source combustion particulate matter (PM). These include (1) metrics to characterize and quantify PM, (2) the need to reconcile ambient and source measurements, (3) the role of atmospheric transformations on modeling emissions and exposures, (4) the impact of sampling conditions on PM measurement, and (5) the potential benefits of novel PM instrumentation. This paper distills the material presented by subject experts and the insights derived from the in-depth discussions that formed the core of each session. The paper's objectives are to identify areas of consensus that allow wider practical application of the past decade's advances in combustion aerosol measurement to improve emissions and air quality modeling, develop emissions reduction strategies, and to recommend directions for progress on issues in which uncertainties remain.
Comparative timing of brood development between multiple- and single-foundress colonies of the paper wasp, Polistes metricus.

. Multiple-foundress colonies of Polistes metricus Say produce their first workers earlier than single-foundress colonies. This is probably an advantage in reducing predation and usurpation by conspecifics and may partially explain the advantage to certain foundresses in joining other foundresses, likely their sisters, rather than establishing their own nests alone. There is no evidence that multiple foundresses work synergistically to accelerate brood development. Rather, foundresses normally join early-established nests so that multiple-foundress nests have an early start and thus produce workers early in the season.
Designing between borders: the distributed UI design team at Adobe

The User Interface Team at Adobe has members in 8 (soon to be 9) national and international sites including Germany, Canada, and India. What does it mean to have a centralized UI team with so many remote members? In this paper we discuss how our locations came into being, challenges and issues encountered, and steps we've taken to build a cohesive team identity. We also discuss the vision driving plans for growing teams in India and Japan.
Precut sphincterotomy: efficacy for ductal access and the risk of adverse events

Background Successful ductal access is achieved in 90% of patients who undergo ERCP. Precut sphincterotomy has been advocated when routine cannulation is not possible. Objective To evaluate the efficacy of precut sphincterotomy for ductal access and the risk of adverse events including post-ERCP pancreatitis (PEP) associated with it. Design Retrospective analysis of ERCP procedures performed from 2002 to 2011. Setting Referral center. Patients A total of 10,202 consecutive patients who underwent native cannulation ERCP. Main Outcome Measurements Efficacy for ductal access and risk of adverse events including PEP. Results A total of 706 patients required precut sphincterotomy, 614 of whom (86.9%) had successful biliary cannulation. PEP was diagnosed in 58 (8.2 %), perforation in 6 (0.8%), and bleeding in 49 (6.9%) patients. On multivariate analysis, unsuccessful precut sphincterotomy (odds ratio [OR] 2.59; 95% confidence interval [CI], 1.53–4.40; P P = .004) were associated with increased risk of the development of adverse events. Female sex (OR 2.42; 95% CI, 1.29-4.55; P = .006) and sphincter of Oddi dysfunction (OR 2.77; 95% CI, 1.16-6.60; P = .02) were associated with an increased risk of PEP. Limitations Retrospective study. Conclusions Precut sphincterotomy is effective in achieving ductal access when standard cannulation techniques fail. A successful precut sphincterotomy is not associated with an increased risk of adverse events.
Smartphone-based hierarchical crowdsourcing for weed identification

A novel hierarchical crowdsourcing-based system for weed identification.Combines image processing with crowdsourcing weed identification.Framework for unsupervised determination of crowd hierarchy.Prototype that supports low cost and accurate weed identification. Weed infestation is a common problem in agriculture that adversely affects crop production. Given severe constraints on the budget of many land-grant universities due to the economic downturn, extension services or agencies responsible for educating farmers and assisting them with the application of advancements in agricultural research, have taken a hit. To adapt to the current economic climate without adversely affecting the quality of programs for weed management, we present a hierarchical system that uses images captured using a smartphone application, a backend image processing algorithm, and two levels of crowdsourcing to identify weed images. The first of the two crowdsourcing levels consist of a non-expert crowd contributed by Amazon Mechanical Turk (AMT) and the second level consists of a crowd composed of experts such as county extension agents. We present a probabilistic decision engine to determine the suitability of two levels of crowdsourcing for identifying the weed image. We have evaluated the designed system using test weed images and we show that 80% of the weeds in our test set can be identified using the low cost AMT crowd while incurring a maximum latency of 3h. Our system can help reduce the loses caused by the delay in identifying weeds, and hence, lead to quick remedial control practices applied to contain weed infestations.
Calbindin D9k is not required for 1,25-dihydroxyvitamin D3-mediated Ca2+ absorption in small intestine.

Abstract The exact role of calbindin D9k in vitamin D-mediated calcium absorption has been debated but remains unsettled. In 129/OlaHsd mice, calbindin D9k was found highest in duodenum (36–50%) and kidney (24–34%) followed by stomach, lung and uterus. Age does not affect the relative distribution of calbindin D9k but it does decline with age in duodenum of both male and female 129/Ola mice. Recently, we produced a null calbindin D9k mutant 129/OlaHsd mouse; this mouse proved to be indistinguishable from the wild-type in phenotype and in a serum calcium level regardless of age or gender. We have now examined directly whether the mutant mouse can absorb calcium from the intestine in response to the active form of vitamin D. The calbindin D9k null mutant mouse is fully able to absorb calcium from the intestine in response to 1,25-dihydroxyvitamin D3. It is, therefore, clear that calbindin D9k is not required for vitamin D-induced intestinal calcium absorption.
From the School of Nursing Quality and Safety Officer: Nursing Students' Use of Safety Reporting Tools and Their Perception of Safety Issues in Clinical Settings

Improved patient safety and quality are priority goals for nurses and schools of nursing. This article describes the innovative new role of quality and safety officer (QSO) developed by one university in response to the Quality and Safety Education for Nurses challenge to increase quality and safety education for prelicensure nursing students. The article also describes the results of a study conducted by the QSO, obtaining information from prelicensure nursing students about the use of safety tools and identifying the students' perceptions of safety issues, communication, and safety reporting in the clinical setting. Responses of 145 prelicensure nursing students suggest that it is difficult to get all errors and near-miss events reported. Barriers for nursing students are similar to the barriers nurses and physicians identify in reporting errors and near-miss events. The survey reveals that safety for the patient is the primary concern of the student nurse.
Lumbar scheuermann’s: A clinical series and classification

Scheuermann's disease of the thoracic spine is a well-defined entity, although its exact etiology is unknown. In the thoracolumbar or lumbar spine however, the criteria are much less strict for the application of this eponym. A retrospective review of all the cases of lumbar Scheuermann's disease seen at the Texas Scottish Rite Hospital revealed two distinct radiographic pictures. These consisted of a "classic" Scheuermann's and an "atypical" type characterized by vertebral end plate changes, disc space narrowing, and anterior Schmorl's nodes, but not otherwise fulfilling Sorenson's criteria. This group tended to occur in more athletic adolescents or those with a history of increased axial stress to the spine. A subgrouping of atypical Scheuermann's disease is proposed and includes acute traumatic intraosseous disc herniation. Based on these findings, a classification of lumbar Scheuermann's disease is proposed.
Effects of rising rural population density on smallholder agriculture in Kenya

Abstract This study measures how Kenyan farmers and farming systems have responded to changes in population density and associated land pressures. Kenya is a relatively densely populated area, with 40% of its rural people residing on 5% of its rural land. We develop a structural model for estimating the impact of population density on input and output prices, farm size, and ultimately on smallholder behavior and agricultural intensification. Evidence is derived from a five-round panel survey between 1997 and 2010. We find a negative relationship between localized population density and farm size, and a positive relationship between population density and measures of land intensification up to roughly 500 persons/km 2 . Beyond this threshold, rising population density is not associated with further increases in land intensification. Some measures of intensification actually show an alarming decline beyond this population density threshold. We also find a relatively weak relationship between population density and off-farm income. Overall, total household income per adult equivalent is found to decline significantly as population density rises. These findings raise serious policy questions about feasible pathways for rural poverty reduction in the context of increasingly land-constrained farming systems.
Why Our Justice System Convicts Innocent People, and the Challenges Faced by Innocence Projects Trying to Exonerate Them

Despite the prominence and success of the over sixty innocence projects in the United States, there is almost no empirical literature discussing how these organizations operate, what resources or factors contribute to their success, and what challenges they must overcome. This article is a foundational step to fill this void. Following a brief introduction, Part I of the article surveys the reasons why innocent individuals get convicted, including: inaccuracy of eyewitnesses, perjured testimony, availability of DNA testing, accuracy of DNA testing and scientific evidence, prosecutorial misconduct, ineffective defense representation, ineffective capital representation, police misconduct: false confessions, and pretrial criminal procedure processes. Part II reviews the institutional development of innocence projects. Part III, based on unprecedented empirical research, analyzes the resources and factors that contribute to an innocence project9s success to determine if a relationship exists between particular factors and an increase in exonerations when compared to other innocence projects. The factors discussed are: finances, staff and volunteers, time distribution per task, age of the innocence project, number of cases seriously reviewed, and state characteristics. The results found a "sweet spot" for each characteristic or resource evaluated, which demonstrated two conclusions: (1) a medium level of resources can achieve success equal to or greater than the success of projects with more resources; and (2) increasing the resources beyond the sweet spot did not necessarily correlate to greater success for the particular innocence project. This part also discusses the issues that innocence projects must overcome to free their clients. Part IV provides modest recommendations for improvements—even though the innocence projects have been exceedingly successful despite their lack of resources.
Catalytic deactivation dynamics of zeolites in multicycle processes

Catalytic deactivation dynamics of zeolites in multicycle processes has been calculated. It has been revealed that in naphthalene sorption on NaX zeolites “surface deactivation” is predominant with its similarity criterion close to unity and a high fraction of deactivation. Calculated data for several multicycle processes are given.
The anti-waggle dance: use of the stop signal as negative feedback

Numerous activities within honey bee (Apis mellifera L.) colonies rely on feedback loops for organization at the group level. Classic examples of these self-organizing behaviors occur during foraging and swarm nest site selection. The waggle dance provides positive feedback, promoting foraging at a specific location or increased scouting at a potential nest site. Rather less well known than the waggle dance, the stop signal, a short vibration often delivered while butting against a dancing bee, is currently best understood as a counter to the waggle dance, offering negative feedback towards the advertised foraging location or nest site. When the stop signal is received by a waggle dancer she is more likely to terminate her dance early and retire from the dance floor. Bees that experienced danger or overcrowding at a food source are more likely to perform the stop signal upon their return to the colony, resulting in an inhibition of foraging at that location. During a swarm’s nest site selection process, scout bees that visited a different site than the one being advertised are more likely to stop-signal the waggle dancer than are scouts that had visited the same site. Over time, the scout bees build recruitment to a single site until a quorum is reached and the swarm can move to it. The balance between the positive feedback from the waggle dance and the negative feedback from the stop signal allows for a more sensitive adjustment of response from the colony as a unit. Many of the processes associated with the feedback loops organizing a honey bee colony’s activities are in striking parallel to other systems, such as intercellular interactions involved in motor neuron function.
Aminooxyacetate inhibits gluconeogenesis by isolated chicken hepatocytes

Although the pathway for glucose synthesis from lactate in avian liver is not thought to involve transamination steps, inhibitors of transamination (aminooxyacetate and L-2-amino-4-methoxy-trans-3-butenoic acid) block lactate gluconeogenesis by isolated chicken hepatocytes. Inhibition of glucose synthesis from lactate by aminooxyacetate is accompanied by a large increase in the lactate-to-pyruvate ratio. Oleate largely relieves inhibition by aminooxyacetate and lowers the lactate-to-pyruvate ratio. In parallel studies with rat hepatocytes, oleate did not overcome aminooxyacetate inhibition of glucose synthesis. The ratios of lactate used to glucose formed were greater than 2 with both rat and chicken hepatocytes, were increased by aminooxyacetate, and were restored toward 2 by oleate. Thus, in the absence of oleate, lactate is oxidized to provide the energy needed to meet the metabolic demand of chicken hepatocytes. Excess cytosolic reducing equivalents generated by the oxidation of lactate to pyruvate are transferred from the cytosol to the mitosol by the malate-aspartate shuttle. Aminooxyacetate inhibits the shuttle and, consequently, glucose synthesis for want of pyruvate.
The Campo Indian Landfill War: The Fight for Gold in California's Garbage

If you are interested in oral history, do not read this book. If, however, you are interested in a concise history of California Indian tribes, the anatomy of a modern landfill, the politics of “no...
The neural pathways, development and functions of empathy

Empathy reflects an innate ability to perceive and be sensitive to the emotional states of others coupled with a motivation to care for their wellbeing. It has evolved in the context of parental care for offspring as well as within kinship. Current work demonstrates that empathy is underpinned by circuits connecting the brainstem, amygdala, basal ganglia, anterior cingulate cortex, insula and orbitofrontal cortex, which are conserved across many species. Empirical studies document that empathetic reactions emerge early in life, and that they are not automatic. Rather they are heavily influenced and modulated by interpersonal and contextual factors, which impact behavior and cognitions. However, the mechanisms supporting empathy are also flexible and amenable to behavioral interventions that can promote caring beyond kin and kith.
When size matters: the dynamic regulation of stereocilia lengths

Stereocilia, the mechanosensitive protrusions in hair cells, are organized into rows of graded heights forming precisely uniform staircase patterns. The actin turnover process in stereocilia follows a treadmill model in which the rate of treadmilling is scaled to the stereocilium's length. Myosin XVa, which is present at the site of actin polymerization at concentrations proportional to the length of the actin filament bundles, plays a combined role with the treadmill machinery in regulating the steady state length of these actin protrusions, together with other myosins localized alongside the actin bundles.
Simple versus complex models: evaluation, accuracy, and combining.

This paper argues that it is premature to decide whether simple forecasting models in demography are more (or less) accurate than complex models and whether causal models are more (or less) accurate than noncausal models. It is also too early to say under what conditions one type of model can outperform another. The paper also questions the wisdom of searching for a single best model or approach. It suggests that combining forecasts may improve accuracy.
Ensemble modeling and related mathematical modeling of metabolic networks

Abstract Metabolic engineering involves the manipulation or modification of key genes in metabolic pathways to accomplish the goal of increasing the production of a substance of interest. While candidate genes for manipulation are commonly chosen through intuition, many effective targets are non-trivial and thus serve as the motivation for mathematical modeling. Effective mathematical modeling strategies allow for a greater insight into the behavior of the biological system, while helping to identify candidate genes for manipulation. In this article, we summarize the advantages and limitations of various modeling methodologies, including both stoichiometric and kinetic approaches, using a simple model system to illustrate their application. As mathematical modeling of metabolic systems becomes more widespread and easy to implement, the iteration between modeling and experiment has the opportunity to become increasingly symbiotic, allowing for experiment to be driven by computation, and computation to be updated and refined by the results of experiment. In this light, we focus our analysis on the newly introduced ensemble modeling methodology. This approach allows for a tighter relationship between computation and experiment, bringing this goal a step closer to common practice.
Protection against radiation damage to organic crystals exciton effects

Abstract The results of Salih and Cosslett (1974) on protection against damage to electron-irradiated anthracene and coronene crystals are discussed. An explanation in terms of an exciton-diffusion model is proposed.
Preparation of cellodextrins: An engineering approach

The combination of Sephadex G-15 and ion-exchange resin columns allows one-step desalting and separation of cellodextrins using water as the sole eluent. The column apparatus described in this paper has the potential of producing up to 3 g cellodextrins in one day. In addition, the columns described are stable and do not require repacking or regeneration after each run. Hence the potential exists for scaling up this system for even greater production of cellodextrins if need be.
Conformal Field Theory and 2D Quantum Gravity

Inspired by the recent work of Knizhnik, Polyakov and Zamolodchikov on the 2D quantum gravity in the “light cone” gauge, we present a proposal for solving the theory in the usual conformal gauge. Our results for the critical exponents of the theory agree with the genus-zero results of KPZ. Since our formalism naturally generalizes to higher-genus Riemann surfaces, we obtain the critical exponents for all genera. The corresponding results for the supersymmetric case are presented. We also show how to calculate correlation functions in these theories.
Ginseng pharmacology: Multiple constituents and multiple actions

Ginseng is a highly valued herb in the Far East and has gained popularity in the West during the last decade. There is extensive literature on the beneficial effects of ginseng and its constituents. The major active components of ginseng are ginsenosides, a diverse group of steroidal saponins, which demonstrate the ability to target a myriad of tissues, producing an array of pharmacological responses. However, many mechanisms of ginsenoside activity still remain unknown. Since ginsenosides and other constituents of ginseng produce effects that are different from one another, and a single ginsenoside initiates multiple actions in the same tissue, the overall pharmacology of ginseng is complex. The ability of ginsenosides to independently target multireceptor systems at the plasma membrane, as well as to activate intracellular steroid receptors, may explain some pharmacological effects. This commentary aims to review selected effects of ginseng and ginsenosides and describe their possible modes of action. Structural variability of ginsenosides, structural and functional relationship to steroids, and potential targets of action are discussed.
Molecular recognition on acoustic wave devices: Zeolite thin films coated with organosilane gate layers

Abstract Microporous thin films composed of a molecular coupling layer, zeolite crystals, and a porous silica overlayer, were formed on the gold electrodes of quartz crystal microbalances (QCMs). The silica overlayer enhances the mechanical stability of the zeolite films, and results in additional surface area and porosity as characterized by the sorption isotherms and transient sorption of vapors with different molecular diameters and different polarities. The protecting silica layer is gas permeable such that the regular zeolite micropores with molecular sieving capability are still accessible in the composite film. A novel surface tailoring technique for the microporous thin films was developed, in which organosilane molecules were chemisorbed on the silica overlayer via siloxane linkages, forming a molecular “gate” at the gas thin film interface. The adsorption of vapors into the microporous zeolite films is therefore controlled by the permeability of the gate layer. Selective adsorption based on kinetic or equilibrium exclusion from the microporous films could be achieved, as demonstrated by discrimination of molecules with similar polarity but different molecular diameters (water vs. ethanol), and effective exclusion of larger molecules such as n-hexane. As a result of the increase in the vapor sorption selectivity and reduction of the external surface area of the thin films, the modified QCMs show high selectivity towards water over other molecules.
Transmission of Mannheimia haemolytica from domestic sheep (Ovis aries) to bighorn sheep (Ovis canadensis): unequivocal demonstration with green fluorescent protein-tagged organisms.

Previous studies demonstrated that bighorn sheep (Ovis canadensis) died of pneumonia when commingled with domestic sheep (Ovis aries) but did not conclusively prove that the responsible pathogens were transmitted from domestic to bighorn sheep. The objective of this study was to determine, unambiguously, whether Mannheimia haemolytica can be transmitted from domestic to bighorn sheep when they commingle. Four isolates of M. haemolytica were obtained from the pharynx of two of four domestic sheep and tagged with a plasmid carrying the genes for green fluorescent protein (GFP) and ampicillin resistance (APR). Four domestic sheep, colonized with the tagged bacteria, were kept about 10 m apart from four bighorn sheep for 1 mo with no clinical signs of pneumonia observed in the bighorn sheep during that period. The domestic and bighorn sheep were then allowed to have fence-line contact for 2 mo. During that period, three bighorn sheep acquired the tagged bacteria from the domestic sheep. At the end of the 2 mo...
Engineering the aggregation properties of dodecameric glutamine synthetase: a single amino acid substitution controls ‘salting out’

Escherichia coli glutamine synthetase (GS) is a dodecamer of identical subunits which are arranged as two face-to-face hexameric rings. In the presence of 10% ammonium sulfate, wild type GS exhibits a pH-dependent "salting out' with a pKa of 4.51. Electron micrographs indicate that the pH-dependent aggregation corresponds to a highly specific self-assembly of GS tubules, which result from stacking of individual dodecamers. This stacking of dodecamers is similar to the metal ion-induced GS tubule formation previously described. Site-directed mutagenesis experiments indicate that the N-terminal helix of each subunit is involved in the salting out reaction, as it is in the metal-induced stacking. A single substitution of alanine for His4 completely abolishes the (NH4)2SO4-induced aggregation. However, the H4C mutant protein does nearly completely precipitate under the same salting out conditions. Mutations at other residues within the helix have no effect on the stacking reaction. Differential catalytic activity of unadenylylated GS versus adenylylated GS has been used to determine whether wild type dodecamers "complement' the H4A mutant in the stacking reaction. The complementation experiments indicate that His4 residues on both sides of the dodecamer-dodecamer interfaces are not absolutely required for salting out, although the wild type dodecamers clearly stack preferentially with other wild type dodecamers. Approximately 20% of the protein precipitated from the mixtures containing the wild type GS and the H4A mutant is the mutant. The implications of these results for protein engineering are discussed.
The Neuroscientific Basis for Aesthetic Preference as an Intervention for Drug Craving Associated with Addiction

Substance Use Disorders remain a costly and dangerous illness despite decades of focused research and a sophisticated understanding of the mechanisms of acute and chronic use in the brain. It is clear that available therapies have only partial efficacy and effort should be made to translate a growing neuroscience understanding to improved therapeutic interventions. Compelling evidence suggests that the acute reinforcing effects of drugs of abuse are due to increased dopamine release in the nucleus accumbens, a brain mechanism associated with the processing of reward and saliency. But, with chronic drug use, select elements of striatal dopaminergic neurotransmission (receptors, transports, enzymes) are down-regulated, rendering a hypodopaminergic state when not augmented by drug use. This state contributes to drug craving, seeking, and ultimately relapse. Hence it is a target for relapse prevention. Recently it has been confirmed that listening to highly pleasurable music can induce not only a strong psychophysiologic response, but also dopamine release in the same neurocircuits as drugs of abuse. Hypothetically this effect of music could have therapeutic potential as an inducer of dopamine release that might ameliorate the hypodopaminergic state of the abstinent addict as a form of agonist substitution. However, a thorough review of the literature found no clinical trials assessing this potential therapeutic effect. Obstacles for consideration in such a trial are also discussed.
Serum Cholinesterase Variants: Examination of Several Differential Inhibitors, Salts, and Buffers Used to Measure Enzyme Activity

Dibucaine, used as a differential inhibitor with acetyl-, propionyl-, and butyrylthiocholine as substrate, clearly identified the "usual" and "atypical" serum cholinesterases. Succinylcholine was also used successfully as a differential inhibitor with butyrylthiocholine as substrate. Sodium fluoride, used as a differential inhibitor, gave conflicting results, depending on whether Tris or phosphate buffer was used in the assay. Mono- and divalent cations (NaCl, KCl, MgCl2, CaCl2, and BaCl2) activated the "usual" and inhibited the "atypical" enzyme at low concentrations. The "usual" enzyme had the same activity in 0.05 mol of Tris or phosphate buffer per liter, while the heterozygous and "atypical" enzymes showed 12 and 42% inhibition, respectively, when assayed in the phosphate buffer. Kinetic studies showed the phosphate acted as a competitive inhibitor of "atypical" enzyme. K m values, determined for "usual" and "atypical" enzymes, were 0.057 and 0.226 mmol/liter, respectively, with butyrylthiocholine as substrate.