cssi/SciSciGPT-SciSciNet huggingface dataset:
Cellular sensing and transport of metal ions: implications in micronutrient homeostasis

Micronutrients include the transition metal ions zinc, copper and iron. These metals are essential for life as they serve as cofactors for many different proteins. On the other hand, they can also be toxic to cell growth when in excess. As a consequence, all organisms require mechanisms to tightly regulate the levels of these metal ions. In eukaryotes, one of the primary ways in which metal levels are regulated is through changes in expression of genes required for metal uptake, compartmentalization, storage and export. By tightly regulating the expression of these genes, each organism is able to balance metal levels despite fluctuations in the diet or extracellular environment. The goal of this review is to provide an overview of how gene expression can be controlled at a transcriptional, posttranscriptional and posttranslational level in response to metal ions in lower and higher eukaryotes. Specifically, I review what is known about how these metalloregulatory factors sense fluctuations in metal ion levels and how changes in gene expression maintain nutrient homeostasis.
How accurately should we estimate the anatomical source of exhaled nitric oxide

for more than a decade it has been recognized that nitric oxide (NO) appears in the exhaled breath and the level is altered in numerous pulmonary diseases in which inflammation plays an integral role (e.g., asthma) ([1][1], [8][2]). Thus the exhaled NO signal has the potential to uniquely delineate
Effects of partial and continuous reinforcement on acquisition and extinction in classical appetitive conditioning

A study was conducted to determine the effects of a continuous and random 50% schedule of reinforcement on classical appetitive conditioning and extinction of the rabbit’s jaw movement response. It was found that partial reinforcement led to a slower rate of acquisition, lower asymptotic level, and slower rate of extinction. The findings were discussed with regard to incentive theory and stimulus aftereffects accounts of partial reinforcement effects in instrumental reward conditioning.
The A-loop, a novel conserved aromatic acid subdomain upstream of the Walker A motif in ABC transporters, is critical for ATP binding.

ATP-binding cassette (ABC) transporters represent one of the largest families of proteins, and transport a variety of substrates ranging from ions to amphipathic anticancer drugs. The functional unit of an ABC transporter is comprised of two transmembrane domains and two cytoplasmic ABC ATPase domains. The energy of the binding and hydrolysis of ATP is used to transport the substrates across membranes. An ABC domain consists of conserved regions, the Walker A and B motifs, the signature (or C) region and the D, H and Q loops. We recently described the A-loop (Aromatic residue interacting with the Adenine ring of ATP), a highly conserved aromatic residue ∼25 amino acids upstream of the Walker A motif that is essential for ATP-binding. Here, we review the mutational analysis of this subdomain in human P-glycoprotein as well as homology modeling, structural and data mining studies that provide evidence for a functional role of the A-loop in ATP-binding in most members of the superfamily of ABC transporters.
Science Signaling Podcast: 19 June 2012

This Podcast features an interview with Holly Ingraham and Raymond Blind, authors of a Research Article published in the 19 June 2012 issue of Science Signaling . Ingraham and Blind discuss their discovery of an unusual mechanism by which the activity of the nuclear receptor steroidogenic factor 1 (SF-1) is modulated. The phospholipid phosphatidylinositol bisphosphate (PIP 2 ) binds to SF-1 so that its hydrophilic head group is exposed. A nuclear lipid kinase phosphorylates PIP 2 to form PIP 3 while it is bound to SF-1. Whereas the SF-1–PIP 2 complex cannot bind to DNA, the SF-1–PIP 3 complex binds to the promoters of target genes. It is well established that chemical modification of ligands can affect the activity of the receptors to which they are bound, but the mechanism reported in this paper is unusual in that the ligand is chemically modified while bound to the receptor.
Grading Without Points: Does It Hurt Student Performance?

Abstract. We gave students enrolled in a research methods course the option of receiving normal grade feedback on assignments (with point values assigned) or receiving feedback on assignments without point values assigned. With respect to final grades earned, students in the two groups did not differ significantly. Final grades were related to self-report of effort as well as future career plans. We encourage instructors to experiment with the mechanics of grade feedback to optimize educational opportunities for students.
Cancer stem cells: markers or biomarkers?

Introduction The lineages assumed by stem cells during hematopoiesis can be identified by the pattern of protein markers present on the surface of cells at different stages of differentiation. Specific antibodies directed at these markers have facilitated the isolation of hematopoietic stem cells by flow cytometry.
Modeling of convection-dominated thermoporomechanics problems using incomplete interior penalty Galerkin method

Abstract In order to obtain converged and accurate numerical solutions, in general, small time steps are required for time-dependent problems. For popular continuous finite elements, however, the use of small time steps often results in oscillatory pressures and temperatures for thermoporomechanics problems with low conductivities. Moreover, convection-dominated thermal poromechanics problems often have very sharp temperature fronts that propagate over spatial domains. When applied to these problems, continuous elements present serious deficiencies in that large error induced in coarse mesh zones will propagate and pollute the solutions in fine mesh zones. Such oscillatory and polluted solutions are nonphysical and must be precluded. We propose discontinuous Galerkin methods to be alternatives to handle these challenges. This paper focuses on the finite element formulation of the incomplete interior penalty Galerkin method on thermoporoelasticity problems with heat convection. In this formulation, we propose discontinuous spaces for all three field variables. To deal with the convection effect, an upwinding scheme is simply and elegantly implemented through element interfaces, which is favored by the discontinuous Galerkin framework. In addition, the inner pressure boundary conditions important to many engineering problems are also taken into account in our discontinuous Galerkin formulation. Excellent performance of this discontinuous Galerkin method on precluding temperature oscillations and on blocking error propagation is demonstrated through solving a convection-dominated oil well-injection problem.
An invited article Facilitating human–computer communication

Basic cognitive psychology can provide guidelines for how to design computer systems that are easy for people to use. Prior knowledge of the real world and natural language affect the way people use computers, so computer systems that are consistent with this prior knowledge are easier for people to use. Providing users with mental models for a computer system will allow them to solve more complex problems and understand sequences of commands better. Computer systems should be flexible to accommodate the individual differences between users, but the complexity of understandable computer systems is constrained by the limited information processing capacity of users. The domain of human–computer communication promises to be a fertile domain for applied tests of cognitive theories.
Reversible and symmetric rings

Abstract We determine the precise relationships among three ring-theoretic conditions: duo , reversible , and symmetric . The conditions are also studied for rings without unity, and the effects of adjunction of unity are considered.
PCBs in Great Lakes sediments, determined by positive matrix factorization

Abstract Previously determined PCB concentrations in 10 dated sediment cores from Lakes Michigan, Huron, Erie, and Ontario are analyzed by positive matrix factorization in order to find characteristic congener patterns including signs of anaerobic dechlorination. Three or four factors are sufficient to describe the PCB data for each lake. All four lakes are dominated by Aroclors 1248A, 1248G, 1254A, and 1254G. Aroclor 1260 is only a significant factor in Lake Michigan prior to 1975, reflecting in part a usage patterns of heavy chlorinated Aroclors early and less chlorinated Aroclors in the phase-out years in the 1970s. Dated records of factors or sources indicate clear PCB concentration maxima for Lakes Erie (1981) and Ontario(1968), while redistribution of PCBs in the less contaminated Lakes Michigan and Huron has occurred after 1980. Using a single data matrix for all four lakes provides a common basis and possibility to examine low degrees of dechlorination, while individual data matrices for each lake provide more accurate results and better separation of factors. Lakes Ontario, Michigan, and Huron undergo dechlorination via reactions such as 66(24-34) → 25(24-3) and 18(25-2) → 4(2-2) consistent with reactions H' + M, while Lake Erie appears to be dominated by 18(25-2) → 4(2-2) and 53(25-26) → 19(26-2) that are typical for processes M + Q.
A comparison of streaming and microelectrophoresis methods for obtaining the ζ potential of granular porous media surfaces

The electrokinetic behavior of granular quartz sand in aqueous solution is investigated by both microelectrophoresis and streaming potential methods. ζ potentials of surfaces composed of granular quartz obtained via streaming potential methods are compared to electrophoretic mobility ζ potential values of colloid-sized quartz fragments. The ζ values generated by these alternate methods are in close agreement over a wide pH range and electrolyte concentrations spanning several orders of magnitude. Streaming measurements performed on chemically heterogeneous mixtures of physically homogeneous sand are shown to obey a simple mixing model based on the surface area-weighted average of the streaming potentials associated with the individual end members. These experimental results support the applicability of the streaming potential method as a means of determining the ζ potential of granular porous media surfaces.
Contesting hydrofracking during an inter-governmental hearing: Accounting by reworking or challenging the question

An inter-governmental hearing on hydrofracking for natural gas is examined. The Department of Environmental Conservation (DEC) recently released an Environmental Impact Statement (EIS) and takes qu...
Calcitonin gene‐related peptide (CGRP) is a potent non‐endothelium‐dependent inhibitor of coronary vasomotor tone

1 Ring segments of bovine left circumflex coronary artery were pre-contracted with 5-hydroxytryptamine or phenylephrine and then exposed to increasing concentrations of calcitonin gene-related peptide (CGRP) and other drugs. 2 CGRP administration resulted in dose-dependent inhibition of induced tone. Maximal relaxation to CGRP was 89 +/- 5% and the concentration required to achieve 50% maximal relaxation (EC50) was 2.11 +/- 1.35 X 10(-9)M. 3 CGRP-induced relaxation was not affected by removal of endothelial cells nor was it significantly altered by incubation of coronary vessels with atropine, propranolol, phentolamine (all 10(-6)M) or indomethacin (10(-5)M). 4 From these data we conclude that CGRP is a potent inhibitor of coronary artery vasomotor tone which appears to act directly on vascular smooth muscle rather than through the release of a secondary mediator. These data support the possibility that CGRP may play a role in non-adrenergic, non-cholinergic regulation of coronary artery tone.
Age as a predictor of outcome for women with DCIS treated with breast-conserving surgery and radiation: The University of Texas M. D. Anderson Cancer Center experience.

Abstract Purpose: To analyze the long-term outcome of breast conservation therapy in patients with ductal carcinoma in situ (DCIS) in a single institution and to analyze the prognostic importance, if any, of young patient age. Methods and Materials: The hospital records of 150 patients with DCIS treated with surgical excision and radiotherapy at our institution between 1980 and 1997 were retrospectively reviewed. For most of the patients, intraoperative specimen radiographs or postoperative mammograms were available for use in assessing that an adequate surgical resection had been performed. The median patient age was 53 years (range 32–81), with 13% of patients ≤40 years old. Results: At a median follow-up of 63 months, 12 patients had local disease recurrence. The actuarial rate of local recurrence-free survival at 5 and 10 years was 96% and 88%, respectively. Local recurrence correlated with nuclear grade ( p = 0.002) but was not associated with patient age at diagnosis ( p = 0.39). In all cases of local recurrence, patients underwent surgery with or without chemotherapy, and disease control was achieved. Conclusion: The results of this study demonstrate high rates of long-term overall survival, disease-specific survival, and local control in patients with DCIS of the breast treated conservatively with segmental mastectomy and radiotherapy. On the basis of the excellent long-term local control and 100% disease-specific survival rates, we found that patient age does not affect the outcome if the margins are clear. Continued studies in young patients treated with breast conservative therapy for DCIS are needed.
Global observability of flows on the torus: An application of number theory

Kronecker's theorem is used to show that the irrational flows on then-dimensional torus are globally observed by a large class of continuous functions. These results are used to study the observability of Riccati flows on the Grassman manifolds.
The Role of the Aminosugar and Helix Binding in the Thiol-Induced Activation of Calicheamicin for DNA Cleavage

The diynene antitumor antibiotic calicheamicin γ1I (CLMγ1I) cleaves DNA in the presence of thiols and molecular oxygen. The proposal that interaction of CLMγ1I with DNA enhances the rate of this cleavage process has been addressed. The kinetics of CLM activation for DNA cutting by aminoethanethiol and glutathione (GSH) have been investigated for the drug free in solution and primarily bound to DNA. The second-order rate constants for the disappearance of the trisulfide CLMγ1I and for the slower reaction of the principal disulfide intermediate in the activation process have been determined and reveal that both of these reactions are slower in the presence of DNA. In earlier solution studies the second-order reaction rate of CLMγ1I was compared to the rates measured for N-acetylCLM and CLMα3, derivatives lacking an internal free amine. Little difference was observed among these rates, a finding inconsistent with the contention that the ethylamino sugar serves as a general base in the activation process. The...
Chemical analysis of stalk components of Dictyostelium discoideum

Abstract Structural components of the stalks of mature fruiting bodies of Dictyostelium discoideum have been isolated and characterized after solubilizing non-structural components with urea and sodium dodecyl sulfate. The urea/sodium dodecyl sulfate-insoluble stalks are composed of about 52% cellulose, 15% proteins and 3% of a non-cellulosic heteropolymer in a covalently bound matrix. Non-covalently bound fatty acid containing material was also found. The composition and structural interrelationships of these components are essentially identical to that of the urea/sodium dodecyl sulfate-insoluble surface sheath which is produced earlier in development before culmination. These results suggest that the same components are involved in making structural elements which differ substantially in their functional role in the developmental sequence as well as in their spatial and temporal localization and morphological appearance.
On assertion-based encapsulation for object invariants and simulations

In object-oriented programming, reentrant method invocations and shared references make it difficult to achieve adequate encapsulation for sound modular reasoning. This tutorial paper surveys recent progress using auxiliary state (ghost fields) to describe and achieve encapsulation. It also compares this technique with encapsulation in the forms provided by separation logic. Encapsulation is assessed in terms of modular reasoning about invariants and simulations.
Rethinking Percutaneous Paravalvular Leak Closure: Where Do We Go From Here?

Paravalvular leak (PVL) is an uncommon yet serious complications associated with the implantation of surgical prosthetic valves and more recently recognized with transcatheter valves. Renewed interest has developed as relationships have emerged between the degree of paravalvular regurgitation and mortality. 1 Percutaneous closure of PVLs has shown significant promise with contemporary success rates as high as 86%, especially in patients at high risk for surgical repair or replacement. 2,3 Growth in the field of structural heart disease has afforded the adaptation of many technical and procedural advances in an attempt to further improve transcatheter success, while reducing the risk of
A survey of recent developments in multiobjective optimization

Multiobjective Optimization (MO) has many applications in such fields as the Internet, finance, biomedicine, management science, game theory and engineering. However, solving MO problems is not an easy task. Searching for all Pareto optimal solutions is expensive and a time consuming process because there are usually exponentially large (or infinite) Pareto optimal solutions. Even for simple problems determining whether a point belongs to the Pareto set is \(\mathcal{NP}\) -hard. In this paper, we discuss recent developments in MO. These include optimality conditions, applications, global optimization techniques, the new concept of epsilon Pareto optimal solution, and heuristics.
Hydrothermal products of the C3MS2-C12A7-MgO system

Abstract The autoclave products of reduced steel-slag of an electronic furnace mainly containing C3MS2 phase were detected. The hydrothermal products of this slag included calcio-chondrodite, brucite, and hydrogarnet phases. When suitable (CaO + MgO) SiO 2 molar ratios were chosen, C3MS2 can react with SiO2 to produce calcium silicate hydrates tobermorite, xonotlite, gyrolite, and truscottite phases with different saturated water vapor pressures. The phase brucite was present along with tobermorite, whereas phases Mg-xonotlite, Mg-gyrolite, and Mg-truscottite can rarely coexist with brucite. Hydrogarnet phase disappeared when Mg-truscottite was formed.
Sats in the 60s

A 61-year-old man presented to the emergency department (ED) with sudden onset shortness of breath, coughing paroxysms, and a brief loss of consciousness. The emergency medical services (EMS) noted the patient to be diaphoretic and unresponsive, with a prior history of single lung transplantation. His current medications were multiple, without known allergy. Upon ED arrival, the patient was alert and oriented with normal vital signs, except for a marked tachypnea and saturations of 64% on 100% oxygen via a non-rebreather face mask. The initial chest radiograph shows a density in the left upper lung field, missed on the radiologist’s reading of the film (Fig. ​(Fig.1a,1a, arrow). Shortly thereafter, the patient began to cough violently and expelled a large pellet of chalk-like material, ascertained to be the remnants of a calcium supplement. Post expulsion, the oxygen saturation immediately rose to 99% and his respiratory rate decreased to 14. A repeat chest radiograph revealed an absence of the calcified density in the left upper lobe, and clear reduction of adjacent parenchymal atelectasis (Fig. ​(Fig.1b).1b). Clinicians should consider the possibility of pill aspiration on the differential for sudden marked hypoxia and tachypnea, especially in post lung transplant patients. Fig. 1 a Initial and b repeat chest radiographs
A cross disciplinary study of link decay and the effectiveness of mitigation techniques

Background The dynamic, decentralized world-wide-web has become an essential part of scientific research and communication. Researchers create thousands of web sites every year to share software, data and services. These valuable resources tend to disappear over time. The problem has been documented in many subject areas. Our goal is to conduct a cross-disciplinary investigation of the problem and test the effectiveness of existing remedies.
Hafnium silicide formation on Si ( 001 )

The solid-state reaction of thick $(\ensuremath{\sim}50\phantom{\rule{0.3em}{0ex}}\text{nm})$ and thin $(\ensuremath{\sim}\text{monolayer})$ films of Hf with cleaned and oxidized $\text{Si}(001)$ substrates was investigated. Upon annealing to $1000\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$, films of ${\text{HfSi}}_{2}$ were formed after reaction times that depended upon the surface condition of the substrate before deposition. The chemical state of the reacted surfaces was characterized using x-ray photoelectron spectroscopy, and the shifts in binding energy upon silicide formation were recorded. Even for thick films, low-energy electron diffraction (LEED) revealed that the $(2\ifmmode\times\else\texttimes\fi{}1)$ pattern of the Si substrate emerged, suggesting that three-dimensional islanding of the ${\text{HfSi}}_{2}$ film had occurred. The islanding behavior was investigated for both thick and thin films using LEED, atomic force microscopy, and scanning electron microscopy. Streaking in the LEED patterns for the thick films suggest that the island morphology is influenced by the underlying Si substrate.
Network resource efficient routing in mobile ad hoc wireless networks

Network resources in mobile ad hoc wireless networks (MANETs) are constrained due to their dynamic topology and lack of centralized control. Mobile nodes in MANETs tend to broadcast packets to exchange information and consume lots of network resources such as network bandwidth and battery power of each node during forwarding their packets. Hence, the conserving network resource is crucial to maintain the quality of network services without interruptions. In order to discover an ideal routing algorithm that should use minimum network resources and improve network performance, we propose an adaptive-gossiping routing algorithm that saves network bandwidth and energy consumption at each node by reducing the duplicated routing messages. Our new analytical model of adaptive-gossiping probability $$p_{n}$$pn provides a less routing overhead which results in conserving network resources and reducing the end-to-end delay. The both analytical and experimental results of our proposed method confirm its advantages over flooding and static-gossiping based routing protocols in large-scale networks.
Democrat, Republican, or None of the Above? The Role of Religiosity in Muslim American Party Identification

The role of religiosity as an important predictor of partisan identification has been well researched over the years, with most of our understanding of religion focused on Christianity. However, it is not clear that religiosity operates equally for the partisan identification of non-Christian religious groups. One of the most discussed religious minority groups in the United States today is Muslim-Americans. Numbering between 2.3 million and 7 million, Muslim-Americans have been the focus of considerable debate regarding religion and American political inclusion. We argue that religiosity does influence Muslim-American party identification, however not in the same manner as with other groups. While the two major political parties encourage religiosity among Protestants, Jews, and Catholics, they are either silent or opposed to religiosity among Muslims within their parties. Thus, religiosity among Muslim-Americans may not necessarily lead to partisan identification with either Republicans or Democrats. Rather, high levels of religiosity, coupled with perceptions of discrimination against Muslims, may lead many to oppose both major political parties and instead identify with "none of the above." This is not to say that Muslim-Americans reject civic engagement or political participation in the United States, but rather the two
Lipotransfer as an adjunct in head and neck reconstruction.

Objectives To present our technique of lipotransfer and to evaluate a single center's experience in the use of lipotransfer as an adjunct to head and neck reconstruction. Study Design A retrospective review of all patients undergoing lipotransfer over a 5-year period by the senior author was undertaken. A total of 23 patients with a minimum follow-up of 1 year were available for analysis. Methods Patient records were retrospectively reviewed to assess functional (in the case of palate augmentation) and esthetic outcomes. Results Twenty-three patients undergoing lipotransfer as part of their reconstructive effort included (1) eight patients undergoing temporal fossa augmentation following temporalis muscle flap reconstruction for extirpative skull base surgery, (2) six patients undergoing facial defect augmentation following traumatic atrophy, (3) three patients undergoing palatal augmentation for correction of velopharyngeal insufficiency, and (4) six patients undergoing soft tissue augmentation following flap reconstruction of the face. Twenty of the 23 patients had excellent maintenance of graft volume. An adequately vascularized recipient bed appears to be an important factor in determining ultimate graft survival using our technique. Conclusions Lipotransfer of the head and neck represents a simple, effective adjunctive technique providing for large amounts of readily available, well-tolerated soft tissue filler material. Patient selection is important, specifically in regard to determining that there is adequate vascularity of the recipient bed.
Microbial hydrocarbons: back to the future

The defining challenge of energy research in the 21st century is the development and deployment of technologies for large-scale reconfiguration of global energy infrastructure. Modern society is built upon a concentrated yet finite reservoir of diverse hydrocarbons formed through the photosynthetic transformation of several hundred million years of solar energy. In human history, the fossil energy era will be short lived and never repeated. Although the timing of peak oil is extensively debated, it is an eventuality. It is, therefore, imperative that projections for both when it will occur and the degree to which supply will fall short of demand be taken into serious consideration, especially in the sectors of energy technology development, political and economic decision making, and societal energy usage. The requirement for renewable energy systems is no longer a point for discussion, and swift advances on many fronts are vital to counteract current and impending crises in both energy and the environment.
The Big Five and Sexuality Trait Terms as Predictors of Relationships and Sex

Abstract A pool of sexuality trait terms were factor analyzed across two overlapping studies. In both studies the sexuality trait terms loaded heavily on a single unrotated factor. The sexuality trait terms were moderately related to the Big Five, but also displayed variation independent of the Big Five and did not appear to be parallel to any specific Big Five factor. In study one (N = 252) the relation of the sexuality trait terms, gender, and the Big Five to measures of attachment, the life task of intimacy, dating attitudes, and dating history were examined. In study two (N = 189) the relation of the sexuality trait terms, gender, and the Big Five to measures of sexual attitudes and behavior were examined. In both studies multiple regression revealed that the sexuality trait terms had an effect independent of both gender and the Big Five as predictors of sexual and relationship criteria. The differential predictive validity of the sexuality trait terms suggests they may represent a potentially important influence in the areas of sex and relationships that are not at this time classified within the Big Five framework.
Soils and stratigraphy of the laddie creek site (48BH345), an altithermal-age occupation in the big horn mountains, wyoming

Haploborolls and Ustifluvents with A-C horizonation characterize Holocene soil development in alluvium and colluvium of the Laddie Creek valley. Cumulic soils with overthickened A horizons, including those of Altithermal age, have formed along the valley walls under the influence of spring activity from the Amsden Formation (Mississippian-Pennsylvanian). Soil texture, mineralogy, and to some extent color, are inherited largely from sediment derived from the Amsden and Tensleep (Pennsylvanian) Formations. The valley was able to support human occupation during Altithermal time (ca. 7500-4000 B.P.) because of springs emanating from the valley walls. Past spring locations are identified from soil morphology and stratigraphy. Springs are still active along the valley, although they have shifted positions many times in the past. The association of spring soils with Altithermal-age occupation at the site (ca. 6600-5700 B.P.) does not coincide with the caliche concept of the Altithermal paleosol in Holocene alluvial valleys in Wyoming basins as identified by Leopold and Miller. Nevertheless, early man of Altithermal time probably sought higher elevations within mountains of the region where springs offered water and the environs provided food and shelter—thus enabling human groups to survive the drought, and possible high temperatures, which seemingly prevailed in the basins and plains.
A cautionary note: the use of vacuum-assisted closure systems in the treatment of gastrointestinal cutaneous fistula may be associated with higher mortality from subsequent fistula development

During the past several years, vacuum-assisted closure (VAC) systems have been increasingly used in the treatment of gastrointestinal cutaneous fistulas, particularly those associated with open abdomen. Recently, I experienced 2 cases in which the original fistula closed after treatment by the VAC system. However, these patients, who had exposed bowel, developed an additional fistula that required surgery. In a recent article from an intestinal-failure unit in the United Kingdom, Rao et al(1) reported on a series of 29 patients treated with VAC, 6 of whom developed new gastrointestinal cutaneous fistulas. Four of these 6 patients died. My own experiences, plus the report of Rao et al,(1) suggest the possibility that the use of the VAC system in patients with exposed bowel and an open abdomen may be associated with subsequent fistula development. Although the numbers are small, it also raises the question that development of a fistula in a patient treated with VAC may result in higher mortality.
Particulate Pollution and Endothelial Function Déjà Vu All Over Again in the Air

Agrowing body of epidemiological data implicates particulate matter air pollution (PM) as yet another factor in the pathogenesis of cardiovascular disease.1 PM influences susceptibility to hard events and may be particularly harmful to high-risk groups such as people with diabetes, people with hypertension, and people who smoke.2 The synergistic impact of PM in diabetes mellitus is internally consistent with previous observations, demonstrating that risk factors such as hypertension, diabetes, and smoking may potentiate atherosclerosis. Thus, if one were to predict likely pathological mechanisms, recapitulation of some the previously well-characterized pathways through which risk factors such as smoking or diabetes modulate atherosclerosis may be equally applicable to PM-mediated atherogenicity. See p 2913 In this issue of Circulation , O’Neill and colleagues demonstrate that antecedent 6-day moving average levels of PM were negatively associated with endothelium-dependent flow-mediated dilation and nitroglycerin-mediated dilation in 269 subjects with diabetes mellitus (type 1, n=45; type 2, n=182) or subjects at risk for developing diabetes (n=42).3 Although the results of the study represent pooled data from 4 trials, the clinical and environmental variables were merged by date to provide startling insights between variations in vasomotor tone and preceding ambient PM levels. The negative association in the type 2 diabetes population (the majority) was striking and, not surprisingly, drove the results of the study. These results are consistent with the recurring observation of impaired large-vessel endothelial function in people with type 2 diabetes.4 Another notable finding in the present study was the effect of PM on nitroglycerin-mediated dilation. These results are similar to previous studies that noted the impact of risk factors such as diabetes on smooth muscle function and could potentially implicate abnormalities in guanylate cyclase–cyclic guanosine monophosphate signaling pathways to PM.4 Of the 4 metrics of PM measured in the study …
The heterogeneity of muscle

The basic principles of quantitative histochemistry, originated byHolter andLinderstrom-Lang have been applied to skeletal muscle in several laboratories. Data are presented illustrating the remarkable differences in enzyme composition that exist among individual fibers in the same muscle. It is shown that enzyme values tend to separate somewhat into two groups, corresponding to the two major myosin ATPase staining types, but that otherwise the activities range as much as 10-fold over an almost continuous spectrum. Other examples given at the individual fiber level concern (1) the affects of training and detraining on enzymes of energy metabolism, (2) the profound changes that can be produced by prolonged continuous motor nerve stimulation and (3) the striking differences in metabolite responses in different fiber types during intense stimulation.
Holographic Beamsplitter For Multiple Plane Wave Formation With Matched Phasefronts

The design and fabrication of a holographic beamsplitter that will produce multiple phase and amplitude matched output beams from a collimated laser beam is discussed. Multiple exposures are recorded in a dichromated gelatin (DCG) plate to make the output beams seem to emanate from a single point with high diffraction efficiency and low scattering. During fabrication, a technique was developed to verify that the relative phasefronts of all the output beams are matched. The holograting can be designed such that any relative phase, amplitude and angle between the output beams as well as different recording/readout wavelengths can be specified for a variety of applications. A deterministic method of calculating the optimum Bragg angles for the recording beams has been developed to compensate for the wavelength shift between the recording laser and the readout laser. A special emphasis is given to the application of using a laser diode for readout. Specifically, a double grating method is utilized for making the element less sensitive to wavelength drift common to laser diodes. A single small component has been fabricated with output beams in-line with respect to the input beam axis such that it can be configured into compact and rugged optical systems.© (1989) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Transport of turbulence in numerical fluid dynamics

Abstract Recently proposed turbulence transport equations have been incorporated into the Marker-and-Cell method for the numerical calculation of transient flows of viscous incompressible fluids. The results account automatically for the creation, convection, diffusion, and decay of turbulence and for the effects of the turbulence on the mean flow.
Arginase inhibition mediates renal tissue protection in diabetic nephropathy by a nitric oxide synthase 3-dependent mechanism

Recently, we showed that pharmacological blockade or genetic deficiency of arginase-2 confers kidney protection in diabetic mouse models. Here, we tested whether the protective effect of arginase inhibition is nitric oxide synthase 3 (eNOS) dependent in diabetic nephropathy. Experiments were conducted in eNOS-knockout and their wild-type littermate mice using multiple low doses of vehicle or streptozotocin, and treated with continuous subcutaneous infusion of vehicle or the arginase inhibitor S-(2-boronoethyl)-L-cysteine by an osmotic pump. Inhibition of arginases for 6 weeks in diabetic wild-type mice significantly attenuated albuminuria, the increase in plasma creatinine and blood urea nitrogen, histopathological changes, kidney fibronectin and TNF-α expression, kidney macrophage recruitment, and oxidative stress compared with vehicle-treated diabetic wild-type mice. Arginase inhibition in diabetic eNOS-knockout mice failed to affect any of these parameters, but reduced kidney macrophage recruitment and kidney TNF-α expression compared with vehicle-treated diabetic eNOS-knockout mice. Furthermore, diabetic wild-type and eNOS-knockout mice exhibited increased kidney arginase-2 protein, arginase activity, and ornithine levels. Thus, arginase inhibition mediates renal tissue protection in diabetic nephropathy by an eNOS-dependent mechanism and has an eNOS-independent effect on kidney macrophage recruitment.
The comparative performance of the iterative instrumental variables estimator using structural and predictive criteria

The purpose of this paper is to give experimental evidence on the small-sample properties of the iterative instrumental variables estimator originally proposed byLyttkens [1970], relative to the more conventional methods including ordinary least squares, limited information single equation maximum likelihood and three stage least squares.
A double TROSY hNCAnH experiment for efficient assignment of large and challenging proteins

We present an experiment that allows for a straightforward assignment of NMR resonances, even in large and/or challenging proteins. A single 3D double-TROSY experiment provides three pairs of sequential correlations between two alpha carbons, two amide protons, and two nitrogen nuclei. Thus, all correlated nuclei can readily be visualized within all dimensions of the resulting spectrum, and chain elongation of sequential amino acids can be effected with this single data set. This resolves ambiguities occurring in traditional methods which involve time-consuming and cumbersome strip comparisons obtained with series of triple-resonance spectra. The experiment makes use of the double TROSY technique to account for signal intensity losses during transfer and evolution periods and was tested on a 500 μM sample of the 33 kDa nonribosomal peptide synthetase protein EntB.
Corrosion and solubility in a TSP-buffered chemical environment following a loss of coolant accident: Part 3—Calcium

Abstract Bench experiments were conducted to investigate the effect of the presence of trisodium phosphate (TSP) on the corrosion and release of zinc from metallic zinc-bearing surfaces under conditions representative of the containment pool following a postulated loss of coolant accident (LOCA) at a nuclear power generating facility. The experiments showed that in non-buffered (acidic) environments, measurable quantities of zinc are released from zinc-bearing surfaces. Precipitation and solubility of phosphate-based corrosion products, such as zinc phosphate, limit the release of zinc from zinc-bearing surfaces. These experiments have found that under a variety of conditions, including variations of temperature, pH, and across different zinc-bearing surfaces, the release of zinc into solution is limited to
Disseminated Bartonella infection following liver transplantation

Bartonella henselae has not only been identified as the causative agent of cat scratch disease, but it is also associated with other significant infectious syndromes in the immunocompromised population. We describe two cases of B. henselae associated diseases in liver transplant recipients who both had contact with cats. The first recipient developed localized skin manifestation of bacillary angiomatosis in association with granulomatous hepatitis. He tested positive for Immunoglobulin G (IgG) antibodies against B. henselae. The second patient developed axillary lymphadenopathy, with biopsy showing necrotizing granulomatous inflammation and polymerase chain reaction studies were positive for B. henselae DNA. Her serology for bartonellosis showed a fourfold rise in antibody titers during her hospitalization. Both patients responded to treatment with Azithromycin in combination with Doxycycline. These were the only cases within a series of 467 consecutive liver transplants performed in 402 patients performed during a 4-year period. Although bartonellosis is a rare infection in liver transplantation recipients, it should always be included in the differential diagnosis of patients presenting with fever, central nervous system (CNS) symptoms, skin lesions, lymphadenopathy, and hepatitis especially if prior contact with cats is reported.
Lack of growth inhibition or enhancement of gap junctional intercellular communication and connexin43 expression by β-carotene in murine lung epithelial cells in vitro

The carotenoid, beta-carotene, has been examined in human trials as a possible lung cancer chemopreventive agent, but initial results indicate that the compound is ineffective. Here we have considered whether beta-carotene could enhance gap junctional intercellular communication (GJIC) and affect the growth of lung epithelial cells, since these effects may be involved in the carotenoid's chemopreventive actions. In accordance with its lack of lung cancer chemopreventive activity, beta-carotene (1-10 microM; 1-5 days treatment durations) did not affect GJIC, gap junction protein (connexin43; Cx43) expression, or growth in vitro of non-transformed (C10) or neoplastic (E9 and 82-132) murine lung epithelial cells. beta-Carotene enhanced GJIC and Cx43 expression and reduced the growth of C3H10T1/2 murine fibroblasts, however. These data indicate that the effects of beta-carotene on GJIC and growth are cell-specific which may partly explain why the carotenoid is an ineffective lung cancer chemopreventive agent.
Role of numerical simulation in analysis of ground-water quality problems

Abstract The increasing public awareness and concern about the hazards of toxic chemicals contaminating aquifers has created an increased need for predictive capabilities to analyze ground-water contamination problems. Several digital models to simulate the movement and concentration of ground-water contaminants have been documented recently. Most simulate the transport and dispersion of a nonreactive solute, but some include mathematically simple reaction terms to represent decay and sorption processes. For applications to field problems, these solute-transport models impose data requirements that, in general, exceed our practical capabilities to accurately describe the field properties and stresses of the hydraulic and chemical systems. Thus, interpretations based on model analyses must recognize the significance of uncertainties in input data. Models of ground-water systems should be regarded as just one tool among many that can be used in the analysis of a ground-water quality problem. Numerical simulation can help the analyst integrate available data, evaluate conceptual models, test hypotheses pertaining to flow and quality changes, and predict system responses to alternative stresses. The models do not replace field data, but they do offer a feedback mechanism that can help to guide the design of a more effective and more efficient data-collection program.
Structural Basis for Substrate Specificity of Escherichia coli Purine Nucleoside Phosphorylase

Purine nucleoside phosphorylase catalyzes reversible phosphorolysis of purine nucleosides and 2′-deoxypurine nucleosides to the free base and ribose (or 2′-deoxyribose) 1-phosphate. Whereas the human enzyme is specific for 6-oxopurine ribonucleosides, the Escherichia coli enzyme accepts additional substrates including 6-oxopurine ribonucleosides, 6-aminopurine ribonucleosides, and to a lesser extent purine arabinosides. These differences have been exploited in a potential suicide gene therapy treatment for solid tumors. In an effort to optimize this suicide gene therapy approach, we have determined the three-dimensional structure of the E. coli enzyme in complex with 10 nucleoside analogs and correlated the structures with kinetic measurements and computer modeling. These studies explain the preference of the enzyme for ribose sugars, show increased flexibility for active site residues Asp204 and Arg24, and suggest that interactions involving the 1- and 6-positions of the purine and the 4′- and 5′-positions of the ribose provide the best opportunities to increase prodrug specificity and enzyme efficiency.
Cholera toxin modifies diverse GTP-modulated regulatory proteins.

Abstract Cholera toxin (with NAD) has been employed to ADP-ribosylate the putative GTP regulatory proteins in a range of plasma membrane preparations which are associated with either stimulation or both stimulation and inhibition of adenylate cyclase activity. In systems subject to dual regulation, additional bands are encountered which may reflect the inhibitory GTP regulatory unit. In addition, the GTP regulatory proteins involved in the light activation of retinal phosphodiesterase and protein synthesis initiation factor, eIF-2, have been ADP-ribosylated by cholera toxin. In the latter case, the activity of the factor is grossly impaired following the covalent modification. It is suggested that considerable conservation of structure is maintained in this rather diverse group of GTP regulatory proteins.
MO‐E‐I‐609‐02: Imaging Properties of Cone Beam Breast CT‐ Effects of Detector Properties and Imaging Conditions

Purpose: To investigates the effects of detector properties and imaging conditions on the imaging properties of cone‐beam breast CT with both computer simulations and imaging experiments. Method and Materials: Cone beam breast CT was simulated with the breast analytically modeled as cylinder embedded spherical shape soft tissue masses and calcifications. X‐ray spectrum, breast attenuation, geometric magnification, focal spot blurring, x‐ray detection,detector blurring, image pixelization and digitization were all incorporated in computing the projection images.Quantum noise, system noise,detector blurring were also simulated and incorporated in the model. Image filtering and reconstruction were then performed using the Feldkamp algorithm. Simulation was performed for two flat‐panel detectors, one CsI based and the other a‐Se based. Images of phantoms and breast specimens were also obtained to demonstrate the ability of our experimental cone beam breast CT system to image the 3‐D structures of the breast with embedded cancers and calcifications. Results: Our simulation results shows that the a‐Se detector performs slightly better at 30 and 40 kVp's while the CsI detector performs better at 50 or higher kVp's. ImageSNRs are optimized at 50 and 60 kVp for the s‐Se and CsI detector, respectively. Phantom images obtained with our experimental system show that with higher dose and smaller pixel size, calcifications as small as could be resolved. Images of breast specimens show excellent separation between glandular and adipose tissues. The speculated nature of the tumor masses can be clearly seen in selected projection while ambiguous in other projections or in regular mammograms. It was also found that inclusion of surgical clips (used to indicate tumor location) had caused detrimental reconstruction artifacts. Acknowledgment: This work was supported in part by a research grant EB000117 from the NIBIB and a research grant CA104759 from the NCI.