cssi/SciSciGPT-SciSciNet huggingface dataset:
Postcesarean delivery epidural patient-controlled analgesia. Fentanyl or sufentanil?

BACKGROUND The highly lipid-soluble opioids, fentanyl and sufentanil, frequently are used in combination with local anesthetic agents and/or epinephrine to provide postoperative epidural analgesia. The authors compared the incidence of side effects and patient satisfaction during prolonged epidural patient-controlled analgesia (PCA) infusions of these opioids in combination with bupivacaine and epinephrine. METHODS Using a double-blind study design, 250 patients scheduled for elective cesarean delivery were, on arrival in the postanesthesia care unit, randomized into two epidural PCA infusion groups: group I (n = 125) received fentanyl 2 micrograms/ml with bupivacaine 0.01% and epinephrine 0.5 micrograms/ml and group II (n = 125) received sufentanil 0.8 micrograms/ml with bupivacaine 0.01% and epinephrine 0.5 microgram/ml. The initial infusion rate was 16 ml/h with self-administered 3-ml boluses every 15 min by PCA as desired. At intervals after discontinuation of the infusion, plasma samples were obtained to determine opioid concentrations. RESULTS The median overall satisfaction scores were 9.0 for group I and 10.0 for group II (difference not significant). Pain relief was satisfactory and comparable in both groups, and all patients could ambulate easily. The total number of times PCA requests were made was greater (P < 0.05, by Wilcoxon rank-sum test) for group I than for group II (106.7 +/- 312 vs. 70.8 +/- 138). There were no differences between the groups with respect to incidence of pruritus, sedation, and nausea; however, vomiting occurred more frequently with sufentanil than with fentanyl (12% vs. 4.8%, respectively; P < 0.05). At approximately 1-2 h after discontinuation of the infusion, 1 patient receiving fentanyl and 42 patients receiving sufentanil complained of lightheadedness and dizziness (P < 0.0001). CONCLUSIONS Epidural PCA in both groups had no serious side effects and achieved a high level of patient satisfaction. Those receiving sufentanil made fewer PCA requests but had a significantly greater incidence of vomiting during the infusion and dizziness after the termination of the infusion. Epidural sufentanil offered no advantages over epidural fentanyl.
Genetic determinants for activated fluoropyrimidine chemotherapy

Fluoropyrimidines (FPs) remain widely used for the treatment of diverse malignancies more than four decades following the initial report of 5-fluorouracil (5FU), the archetypal FP, as a novel compound with potential anti-neoplastic activity. Subsequent decades of research have enriched our understanding of the biochemical mechanisms that are important for FP activation as well as the genetic determinants that are predictive of the likely success, or failure, of FP chemotherapy for a particular individual. The concept that chemotherapy should be customized to complement the genetic profiles of cancer patients has become increasingly important as genotyping of tumor samples has become possible and as the number of available anticancer drugs has increased. Significant progress has been made in identifying the gene expression profiles for cancer patients who are likely to benefit from treatment with FPs. In this review, we will summarize the results of retrospective clinical studies correlating response to FP chemotherapy with the expression of specific genes, such as TS and DPD. We will also present a summary of FPs in current clinical use, including orally bioavailable FPs such as capecitabine, as well as FPs that are in pre-clinical development, such as FdUMP[10]. Refinement of a target population through pharmacogenetic analysis and development of novel FPs that evoke very high response rates in this target population will likely result in the use of FP regimens in the coming era when cancer becomes a largely manageable disease. Drug Dev. Res. 67:119–129, 2006. © 2006 Wiley-Liss, Inc.
Engineering a degradable polyurethane intravaginal ring for sustained delivery of dapivirine

We describe the engineering of a degradable intravaginal ring (IVR) for the delivery of the potent HIV-1 reverse transcriptase inhibitor dapivirine. The degradable polymer used in fabricating the device incorporated poly(caprolactone) ester blocks in a poly(tetramethylene ether) glycol ABA type polyurethane backbone. The polymer was designed to maintain its structure for 1 month during usage and then degrade in the environment post-disposal. In vitro release of dapivirine showed zero-order kinetics for up to 1 month and significant levels of drug release into engineered vaginal tissue. The mechanical properties of the degradable IVR were comparable to those of a widely used contraceptive intravaginal ring upon exposure to simulated vaginal conditions. Incubation under simulated vaginal conditions for a month caused minimal degradation with minimal effect on the mechanical properties of the ring and polymer. The cytotoxicity evaluation of the drug-loaded IVRs against Vk2/E6E7 human vaginal epithelial cells, Lactobacillus jensenii, and engineered vaginal tissue constructs showed the degradable polyurethane to be non-toxic. In vitro evaluation of inflammatory potential monitored through the levels of inflammatory cytokines IL-8, IL-1α, IL-6, IL-1β, and MIP-3α when engineered EpiVaginal™ tissue was incubated with the polyurethanes suggested that the degradable polyurethane was comparable to commercial medical grade polyurethane. These results are encouraging for further development of this degradable IVR for topical vaginal delivery of microbicides.
Dimensioning server access bandwidth and multicast routing in overlay networks

Application-level multicast is a new mechanism for enabling multicast in the Internet. Driven by the fast growth of network audio/video streams, application-level multicast has become increasingly important for its efficiency of data delivery and its ability of providing value-added services to satisfy application specific requirements. From a network design perspective, application-level multicast differs drastically from traditional IP multicast in its network cost model and routing strategies. We present these differences and formulate them as a network design problem consisting of two parts: one is bandwidth assignment in the overlay network, the other is load-balancing multicast routing with delay constraints. We use analytical methods and simulations to show that our design solution is a valid and cost-effective approach. Simulation results show that we are able to achieve network utilization within 10% of the best possible utilization while keeping the session rejection rate low.
Hydrogen Atom Adducts to the Amide Bond. Generation and Energetics of the Amino(hydroxy)methyl Radical in the Gas Phase

The amino(hydroxy)methyl radical (1) represents the simplest model for hydrogen atom adducts to the amide bond. Radical 1 was generated in the gas phase by femtosecond electron transfer to protonat...
Serration behavior and shear band characteristics during tensile deformation of an ultrafine-grained 5024 Al alloy

Abstract The main objective of this work is to understand the major deformation mechanisms operative in the entire plastic strain regime of an ultrafine-grained (UFG) 5024 Al alloy. The initial microstructure in both coarse-grained (CG) and UFG conditions was characterized by transmission electron microscopy and orientation imaging microscopy to better correlate the observed deformation behavior with the microstructural elements. The engineering stress–strain curves in both CG and UFG conditions were serrated from onset of yielding to the point of sample failure although the net intensity of the serrations varied in both the conditions. Interrupted tensile testing with corresponding surface analysis using scanning electron microscopy (SEM) was carried out to clearly demarcate the micro-mechanisms operative in various plastic strain regimes. The serration amplitude as a function of time in UFG material was studied and displayed a different behavior when compared with CG material. The reason for higher non-uniform elongation has been explained in terms of micron-sized shear bands and void coalescence mechanism. Dislocation slip was observed to be the major strain accommodation mechanism, along with shear bands and grain rotation. Analysis of failed specimen surfaces using SEM further assisted in understanding and quantifying the damage accumulation and failure mechanism.
Structural basis for the dsRNA specificity of the Lassa virus NP exonuclease.

Lassa virus causes hemorrhagic fever characterized by immunosuppression. The nucleoprotein of Lassa virus, termed NP, binds the viral genome. It also has an additional enzymatic activity as an exonuclease that specifically digests double-stranded RNA (dsRNA). dsRNA is a strong signal to the innate immune system of viral infection. Digestion of dsRNA by the NP exonuclease activity appears to cause suppression of innate immune signaling in the infected cell. Although the fold of the NP enzyme is conserved and the active site completely conserved with other exonucleases in its DEDDh family, NP is atypical among exonucleases in its preference for dsRNA and its strict specificity for one substrate. Here, we present the crystal structure of Lassa virus NP in complex with dsRNA. We find that unlike the exonuclease in Klenow fragment, the double-stranded nucleic acid in complex with Lassa NP remains base-paired instead of splitting, and that binding of the paired complementary strand is achieved by “relocation” of a basic loop motif from its typical exonuclease position. Further, we find that just one single glycine that contacts the substrate strand and one single tyrosine that stacks with a base of the complementary, non-substrate strand are responsible for the unique substrate specificity. This work thus provides templates for development of antiviral drugs that would be specific for viral, rather than host exonucleases of similar fold and active site, and illustrates how a very few amino acid changes confer alternate specificity and biological phenotype to an enzyme.
Eukaryotic DNA repair is blocked at different steps by inhibitors of DNA topoisomerases and of DNA polymerases α and β

Abstract Inhibitors of (a) DNA topoisomerases (novobiocin and nalidixic acid) and of (b) eukaryotic DNA polymerases α (cytosine arabinoside) and β (dideoxythymidine) blocked different steps of DNA repair, demonstrated by the effects of the inhibitors on the relaxation of supercoiled DNA nucleoids following treatment of human cell cultures with ultraviolet light (1–3 J/m 2 ) or MNNG (5 or 20 μM) and the subsequent restoration of the supercoiled nucleoids during repair incubation. Changes in the supercoiling of nucleoid DNA were assayed by analysis of their sedimentation profiles in 15–30% neutral sucrose gradients. Inhibition of repair by novobiocin was partially reversible; upon its removal from the culture medium, the nucleoid DNA of repairing cells became relaxed. The DNA polymerase inhibitors allowed the initial relaxation of DNA after treatment of the cells with ultraviolet or MNNG but delayed the regeneration of rapidly-sedimenting (supercoiled) nucleoid DNA for 2–4 h. Dideoxythymidine (1 mM) was more effective than cytosine arabinoside (1 μM) in producing this delay, but neither inhibitor by itself blocked repair permanently. Incubation of ultraviolet-irradiated cells with 1 μM cytosine arabinoside plus 1 mM dideoxythymidine blocked the completion of repair for 24 h, whereas incubation with 10 μM cytosine arabinoside or 5 mM dideoxythymidine produced only temporary repair delays of 2–4 h. Thus, it is likely that the two DNA polymerase inhibitors act upon separate targets and that both targets are involved in repair. It is concluded from these and from previous studies that (1) the DNA repair-sensitive target of novobiocin and nalidixic acid in vivo is not a DNA polymerase, but, rather, a DNA topoisomerase; (2) this target affects an initial step of DNA repair leading to the relaxation of supercoiled DNA; (3) the DNA polymerization step of repair may involve both α- and β-type DNA polymerases; and (4) in repair, one type of DNA polymerase may substitute for another.
A Bijection for the Alperin Weight Conjecture in Sn

The Alperin weight conjecture states that if G is a finite group and p is a prime, then the number of irreducible Brauer characters of a group G should be equal to the number of conjugacy classes of p-weights of G. This conjecture is known to be true for the symmetric group S n , however there is no explicit bijection given between the two sets. In this paper we develop an explicit bijection between the p-weights of S n and a certain set of partitions that is known to have the same cardinality as the irreducible Brauer characters of S n . We also develop some properties of this bijection, especially in relation to a certain class of partitions whose corresponding Specht modules over fields of characteristic p are known to be irreducible.
Steel self-centering moment frames with collector beam floor diaphragms

Abstract Following a major earthquake, self-centering moment resisting frames (SC-MRFs) are capable of returning to their original plumb position and sustaining little structural damage. Under earthquake loading, these frames are characterized by a gap that develops between one of the beam flanges and the column face at the connection. This gap causes the frame to expand and therefore imposes special design requirements on the floor diaphragm and on the floor system (e.g. filler beams and slab) that are connected to it. Through nonlinear analyses of several floor diaphragm designs, this paper examines the influence that the floor diaphragm stiffness, strength, and configuration have on the seismic response of SC-MRFs. The floor diaphragm is represented by collector beams that transfer the inertia forces from the building floor to the SC-MRF. This work also presents several equations that are used to predict the effect that the floor diaphragm has on the axial force and moments that develop in the SC-MRF beams. This effect is shown to not be negligible. Finally, practical considerations related to the construction of SC-MRFs that use collector beams as the floor diaphragm are discussed.
Collagen mimetic peptide-conjugated photopolymerizable PEG hydrogel

Collagen mimetic peptide (CMP) with a specific amino acid sequence, -(Pro-Hyp-Gly)(x)-, forms a triple helix conformation that resembles the native protein structure of natural collagens. CMP previously has been shown to associate with type I collagen molecules and fibers via a strand invasion process. We hypothesized that when poly(ethylene glycol) (PEG) hydrogel, a non-adhesive tissue engineering scaffold, is conjugated with CMP, it may retain cell-secreted collagens and also form physical crosslinks that can be manipulated by cells. A photopolymerizable CMP derivative was synthesized and copolymerized with poly(ethylene oxide) diacrylate to create a novel PEG hydrogel. In a model retention experiment, diffusional loss of type I collagen that was added to the hydrogel was limited. Chondrocytes were encapsulated in the hydrogel to examine its use as a tissue engineering scaffold. After 2 weeks, the biochemical analysis of the CMP-conjugated PEG gel revealed an 87% increase in glycosaminoglycan content and a 103% increase in collagen content compared to that of control PEG hydrogels. The histology and immunohistochemistry analyses also showed increased staining of extracellular matrix. These results indicate that the CMP enhances the tissue production of cells encapsulated in the PEG hydrogel by providing cell-manipulated crosslinks and collagen binding sites that simulate natural extracellular matrix.
Can First-Order Logical Truth be Defined in Purely Extensional Terms?

W. V. Quine thinks logical truth can be defined in purely extensional terms, as follows: a logical truth is a true sentence that exemplifies a logical form all of whose instances are true. P. F. Strawson objects that one cannot say what it is for a particular use of a sentence to exemplify a logical form without appealing to intensional notions, and hence that Quine's efforts to define logical truth in purely extensional terms cannot succeed. Quine's reply to this criticism is confused in ways that have not yet been noticed in the literature. This may seem to favour Strawson's side of the debate. In fact, however, a proper analysis of the difficulties that Quine's reply faces suggests a new way to clarify and defend the view that logical truth can be defined in purely extensional terms.
A rapid method for determining the sterility of frozen-reconstituted blood.

A rapid, fast, and accurate method of determining bacterial contamination in blood units is needed to provide a safe unit of frozen- reconstituted blood which can be stored at 4 C after thawing for more than the 24 hours currently allowed by law. The Bactec instrument seems to provide this method. It detects most of the organisms which have been reported in contamineted blood, and does this in a short enough period of time that any organisms introduced into the blood unit during the sampling process will not grow sufficiently to contaminate the unit while the culturing process is going on.
Managing library image as a resource

Purpose – The purpose of this article is to discuss the importance of managing the library's and the director's images.Design/methodology/approach – The approach is to introduce the idea of image as a resource and then discuss how it should be properly managed.Findings – The findings are that the library's image is closely related to that of its director and an image of great service is a key to the library's general health.Originality/value – The value of this article is in learning how to cultivate the proper image as a director and for the library in order to reap the benefits of better funding and other types of support.
Radiofrequency heating for striae: Does it work?

This issue of the Journal of Dermatological Treatment includes an uncontrolled trial of a radiofrequency device for the treatment of striae (1). The uncontrolled trial found promising results, with 2 of the 34 patients achieving >75% improvement in the striae and about a fourth of subjects having 50-75% improvement.
Phospholipase A2 and its molecular mechanism after spinal cord injury.

Phospholipases A2 (PLA2s) are a diverse family of lipolytic enzymes which hydrolyze the acyl bond at the sn-2 position of glycerophospholipids to produce free fatty acids and lysophospholipids. These products are precursors of bioactive eicosanoids and platelet-activating factor which have been implicated in pathological states of numerous acute and chronic neurological disorders. To date, more than 27 isoforms of PLA2 have been found in the mammalian system which can be classified into four major categories: secretory PLA2, cytosolic PLA2, Ca2+-independent PLA2, and platelet-activating factor acetylhydrolases. Multiple isoforms of PLA2 are found in the mammalian spinal cord. Under physiological conditions, PLA2s are involved in diverse cellular responses, including phospholipid digestion and metabolism, host defense, and signal transduction. However, under pathological situations, increased PLA2 activity, excessive production of free fatty acids and their metabolites may lead to the loss of membrane integrity, inflammation, oxidative stress, and subsequent neuronal injury. There is emerging evidence that PLA2 plays a key role in the secondary injury process after traumatic spinal cord injury. This review outlines the current knowledge of the PLA2 in the spinal cord with an emphasis being placed on the possible roles of PLA2 in mediating the secondary SCI.
STRAIN TO EVALUATE VENTRICULAR FUNCTION IN FONTAN PATIENTS UNDERGOING EXERCISE CARDIAC MAGNETIC RESONANCE IMAGING

Feature tracking strain (FTS) is a new technique to assess cardiac function from cardiac magnetic resonance (CMR) images. We compared FTS with conventional function parameters in single ventricle undergoing exercise CMR. 28 Fontan subjects underwent a resting and exercise CMR. Segmented balanced
Keyboard use and musculoskeletal outcomes among computer users.

Background: In this review, the epidemiological evidence examining associations between upper extremity musculoskeletal symptoms and disorders and keyboard use intensity (hours of computer use-per day or per-week) and computer user posture was explored. Methods: An OVID Medline® literature search was conducted to identify papers published in the peer-reviewed medical literature between 1966 and November, 2005. A total of 558 citations were found and reviewed. Those papers in which associations between musculoskeletal outcomes and (1) posture (ascertained by a study investigator) or (2) computer use, in units of hours-per-day, hours-per-week, or as a percent of work-time, were included in the review. Results: Thirty-nine epidemiological studies examining associations between computer use and MSD outcomes were identified. While the observational epidemiological literature was heterogeneous, some trends did emerge. It appears that the most consistent finding was the association observed between hours keying and hand/arm outcomes. Associations between some postural effects and musculoskeletal outcomes may also be inferred from the literature. In particular, placing the keyboard below the elbow, limiting head rotation, and resting the arms appears to result in reduced risk of neck/shoulder outcomes. Minimizing ulnar deviation and keyboard thickness appears to result in reduced risk of hand/arm outcomes. Conclusions: Several methodological limitations, including non-representative samples, imprecise or biased measures of exposure and health outcome, incomplete control of confounding, and reversal of cause and effect, may contribute to the heterogeneity of observed results. Suggestions are made for improving the validity of future investigations.
Brief skin temperature changes towards thermoneutrality trigger REM sleep in rats

Abstract When rats were in slow-wave sleep (SWS) at an environmental temperature (23°C) below their thermoneutral zone (27–31°C), brief skin warming by either radiant heating, or forced air convection resulted in REM sleep on 79–80% of the trials. During control nonwarmed SWS bouts, the animals went into REM sleep on only 22–24% of the trials. When the environmental temperature was above thermoneutrality, 34°C, lowering skin temperature by convective cooling resulted in REM sleep entry 68% of the time, compared to 21% for noncooled, control trials. Skin warming and cooling at 29°C decreased the percent occurrence of REM sleep to 22% and 9% respectively, for at this thermoneutral temperature 46% of the control SWS bouts ended in REM sleep. Thus, peripheral temperature changes towards thermoneutrality trigger REM sleep in mildly thermally stressed rats.
Opiates, endorphins, and the developing organism: A comprehensive bibliography, 1982–1983

Abstract A comprehensive bibliography of the literature concerned with opiates, endorphins, and the developing organism for 1982 and 1983 is presented. Utilized with a companion paper ( Neurosci Biobehav Rev 6: 439–479, 1982) these articles cover clinical and laboratory references beginning in 1875. For the years 1982 and 1983, a total of 385 citations was recorded. A series of indexes accompanies the citations in order to make the literature more accessible. These indexes are divided into clinical and laboratory topics. The clinical section is subdivided into: age of subject examined, maternal aspects, the fetus, and the offspring. The laboratory section is subdivided into: type of opiate/endorphin studied, species utilized, and major subject areas explored.
Mast Cell Degranulation Mediates Compound 48/80-induced Hyperalgesia in Mice

Mast cells mediate allergies, hypersensitivities, host defense, and venom neutralization. An area of recent interest is the contribution of mast cells to inflammatory pain. Here we found that specific, local activation of mast cells produced plantar hyperalgesia in mice. Basic secretagogue compound 48/80 induced plantar mast cell degranulation accompanied by thermal hyperalgesia, tissue edema, and neutrophil influx in the hindpaws of ND4 Swiss mice. Blocking mast cell degranulation, neutrophil extravasation, and histamine signaling abrogated these responses. Compound 48/80 also produced edema, pain, and neutrophil influx in WT C57BL/6 but not in genetically mast cell-deficient C57BL/6-KitW-sh/W-sh mice. These responses were restored following plantar reconstitution with bone marrow-derived cultured mast cells.
To shrink or not to shrink.

In this issue of Blood, Andolfo and colleagues show that dehydrated hereditary stomatocytosis (DHSt), an inherited red cell disorder, is associated with a number of distinct germline mutations in PIEZO1, a stretch activated cation channel, in 26 affected individuals from 7 families. 1
Experimental measurements and simulation of mixing and chemical reaction in a stirred tank

Effects of mixing on the rate of second-order chemical reactions have been studied by measuring the time-average degree of conversion at enough points in a steady-state, continuous-flow stirred reactor to provide comparisons with numerical simulations of the same reactions using a standard Reynolds-averaged turbulence simulation code with an added closure. The reactants were introduced in widely separated feed streams in order to provide a difficult test for the measurements and simulations. Concentration and segregation measurements were made with two fluorescence based methods - one remote and one using a fiber optic probe. The rates of mixing and reaction were simulated using the Corrsin mixing term and the Spalding segregation production term with the Paired-Interaction reaction closure term. On a etudie les effets du melange sur la cinetique des reactions chimiques de deuxieme ordre en mesurant le degre de conversion moyenne dans le temps pour un nombre impotant de points dans un reacteur agite a ecoulement continu en regime permanent. Ces effets mesures ont ete compares a des simulations numeriques effectues avec un code de simulation de la turbulence de Reynolds moyenne classique muni d'une condition de clǒture. Les reactifs ont ete introduits dans des courants d'alimentation largement separes afin de fournir un test difficile pour les mesures et simulations. Des mesures de concentration et de segregation ont ete prises avec deux methodes s'appuyant sur la fluorescence - l'une a distance et l'autre a l'aide d'une sonde a fibres optiques. Les vitesses de melange et de reaction ont ete simulees par une terme de melange de Corrsin et le terme de production de segregation de Spalding avec le terme de clǒture de reaction a interaction jumelee.
X-RAY ABSORPTION STUDIES OF CH3HG+-BINDING SITES IN HUMIC SUBSTANCES

Abstract Methylmercury cation (CH3Hg+) is known to have a strong affinity for organic matter in soil, sedimentary, and aquatic environments. The objective of this study is to determine the dominant ligands binding CH3Hg+ in humic acids by evaluating several CH3Hg+-ligand complexation models, using mercury LIII-edge extended X-ray absorption fine structure (EXAFS). The model CH3Hg+ binding ligands examined in this study include thiol (-SH), hydrogen polysulfide (-SSH or -SSSH), sulfide (-S-), disulfide (-SS-), carboxyl (-COOH), and amine (-NH2). Based on the atomic geometry around mercury in each model structure, we distinguished CH3Hg+-binding ligands in two different humic acids (soil and aquatic). We observed CH3Hg+ preferentially binds to thiol ligands. After saturating reactive thiol ligands, the majority of CH3Hg+ binds to carboxyl ligands rather than to amine or other reduced sulfur ligands than thiol. We found no evidence of significant CH3Hg+-sulfide/disulfide or CH3Hg+-hydrogen polysulfide complexes in any samples. When CH3Hg+ binds to a humic ligand, the C-Hg bond in CH3Hg+ remains intact. Some heavy atoms are proximately coordinated around the mercury atom in the sample containing the highest CH3Hg+ levels used in this study.
Nuclear Glucocorticoid Binding in Chronic Lymphatic Leukemia Lymphocytes

A reliable procedure is described for isolating 3H-triamcinolone acetonide (3H-TA) receptor complexes from purified chronic lymphatic leukemia (CLL) lymphocyte nuclei, based on the use of carbobenzoxy-L-phenylalanine (CBZ-L-phe) to prevent breakdown of hormone-receptor complexes during extraction of nuclei with 0.6M KC1. Using this method, specific nuclear glucocorticoid binding was demonstrated in 14/14 patients with untreated CLL. No correlation was found between levels of nuclearassociated 3H-TA and peripheral white blood cell count or rosetting ability of circulating lymphocytes.
Reflections on Christian–Muslim Dialogue: The Hermeneutics of Messianism

The article points to the dimension of waiting in Jewish, Christian and Shi‘a Muslim thinking as one particular feature of these traditions. There is a need to distinguish between escapist and productive eschatology. The whole question might also be a feature in a discussion on the interrelationship in international relations of the concepts of realism and idealism and the possible contribution of religion.
Cavity-induced enantioselectivity reversal in a chiral metal–organic framework Brønsted acid catalyst

A pair of highly porous chiral metal–organic frameworks (CMOFs 1 and 2) were constructed from [Cu2(carboxylate)4] secondary building units (SBUs) and chiral 3,3′,6,6′- or 4,4′,6,6′-tetra(benzoate) ligands derived from 1,1′-binaphthyl-2,2′-phosphoric acid. Both 1 and 2 were active catalysts for Friedel–Crafts reactions between indole and imines. Interestingly, the 1-catalyzed asymmetric reactions yielded the major enantiomers of the opposite chirality to those afforded by the corresponding homogeneous catalyst. Structural analyses and QM/MM calculations revealed that the flip of product handedness results from the chiral environment of CMOF-1 cavity, similar to enzymatic catalysis in which the product stereoselectivity is determined by the enzyme pocket.
Prolonged Atrial Natriuretic Peptide Exposure Stimulates Guanylyl Cyclase-A Degradation

Natriuretic peptide receptor-A (NPR-A), also known as guanylyl cyclase-A, is a transmembrane receptor guanylyl cyclase that is activated by the cardiac hormones atrial natriuretic peptide and B-type natriuretic peptide. Although ligand-dependent NPR-A degradation (also known as down-regulation) is widely acknowledged in human and animal models of volume overload, down-regulation in cultured cells is controversial. Here, we examined the effect of ANP exposure on cellular NPR-A levels as a function of time. Relative receptor concentrations were estimated using guanylyl cyclase and immunoblot assays in a wide variety of cell lines that endogenously or exogenously expressed low or high numbers of receptors. ANP exposures of 1 h markedly reduced hormone-dependent but not detergent-dependent guanylyl cyclase activities in membranes from exposed cells. However, 1-h ANP exposures did not significantly reduce NPR-A concentrations in any cell line. In contrast, exposures of greater than 1 h reduced receptor concentrations in a time-dependent manner. The time required for half of the receptors to be degraded (t(1/2)) in primary bovine aortic endothelial and immortalized HeLa cells was approximately 8 h. In contrast, a 24-h exposure of ANP to 293T cells stably overexpressing NPR-A caused less than half of the receptors to be degraded. To our knowledge, this is the first report to directly measure NPR-A down-regulation in endogenously expressing cells. We conclude that down-regulation is a universal property of NPR-A but is relatively slow and varies with receptor expression levels and cell type.
Aggregation, molecular recognition and the role of water in peptide crystals

Some generalizations based on numerous crystal-structure analyses of 8- to 16-residue peptides that form 310- and/or α-helices are presented. New data include five decapeptides, each containing one non-standard residue, dipropylglycine or dibutylglycine. Also presented is a new model for an ion transport channel based on the structures of three zervamicin polymorphs.
Coupled nonlinear electrodynamics of type-II superconductors in the mixed state

A theory of the nonlinear electrodynamics of isotropic high-\ensuremath{\kappa} type-II superconductors containing an array of vortices is presented. The theory generalizes a self-consistent approach to vortex dynamics wherein the effects of nonlocality, vortex inertia, pinning, flux flow, and flux creep are treated in a unified fashion. We derive and solve a single vector partial differential equation describing the nonlinear response of a type-II superconductor at frequencies well below the gap frequency. The generation of nth-order harmonics due to bilinear field nonlinearity is discussed.
A Semiautomated Device for Controlled Atmospheres in Optical Emission Spectroscopy

In connection with the determination of trace heavy metals in animal and plant tissue by optical emission spectroscopy, the need arose for a device that could maintain controlled atmospheres at the analytical gap at steady state conditions during high current dc arc excitation periods in which relatively large amounts of matrix constituents were vaporized. Operational needs required precise and continuous adjustment of electrode position, minimal contamination risk, and suitability for routine use.
Local food and the problem of public authority.

As Wendell Berry once wrote, "how we eat determines, to a considerable extent, how the world is used."1 In this deceptively simple statement, the doyen of neo-agrarianism neatly summarized why we should all take a keen interest in and responsibility for the way we produce, distribute, and consume our food. On one level, of course, the reasons for doing so are obvious. As "foodie" journalists and high-profile academics frequently remind us,2 careless eating invites a variety of negative physiological repercussions, ranging from obesity and heart disease to food poisoning, endocrine disruption, and cancer. Yet public concerns over the effects of careless eating reach well beyond health issues. Berry and other advocates of sustainable agriculture maintain that careless eating has played a key role in the relentless industrialization of our food system by creating a sustained and frequently unwitting demand for highly processed foods, factoryfarmed meats, genetically modified crops, and blemish-free produce shipped yearround over immense distances. In turn, sustainable agriculturalists argue, the industrial system that has allowed these foods to become a central part
Estimating the age of Antarctic larval fish from otolith microstructure using light and electron microscopy

Larval fish of Antarctica have very narrow rings on their otoliths (<1 μm) that may not be resolved with light microscopy. In this study, age data from the otoliths of larval Nototheniidae (Gobionotothen gibberifrons and Lepidonotothen larseni), determined using light and scanning electron microscopy, are compared. Rings 0.4 μm wide were observed on otoliths viewed under electron microscopy; however, light microscopy could only resolve rings ⩾ 0.5 μm wide. Scanning electron microscopy is more time consuming and costly than light microscopy but has greater resolving power and is recommended to validate ring counts made using light microscopy in otolith studies with Antarctic larval fish.
A prospective study for the detection of vascular injury in adult and pediatric patients with cervicothoracic seat belt signs.

Background: A delayed diagnosis of injury to cervicothoracic vessels from blunt trauma may cause significant adverse sequelae. The association of a cervicothoracic seat belt sign with such an injury is unknown. Methods: Algorithms were prospectively studied for the detection of occult vascular injury in patients with cervicothoracic seat belt signs. Patients with neck seat belt signs underwent arteriography or computed tomographic angiography (CTA). Those with thoracic seat belt signs underwent aortography/arteriography if a ruptured thoracic aorta or injury to a great vessel was suspected or a neurovascular abnormality was present. Results: During a 17-month period, 797 patients were admitted to the trauma service secondary to motor vehicle crashes. One hundred thirty-one (16.4%) had cervical or thoracic seat belt signs. Four (3%) of the patients had carotid artery injuries, the presence of which was strongly associated with a Glasgow Coma Scale score 16 (p < 0.0001), and the presence of a clavicle and/or first rib fracture (p < 0.0037). Of the remaining patients, 17 had thoracic trauma. There were no vascular injuries in the children and only one had thoracic trauma. Conclusion: The algorithms are safe and accurate for the detection of cervicothoracic vascular injury in adult and pediatric patients with seat belt signs. The cervicothoracic seat belt mark and an abnormal physical examination are an effective combination in screening for cervicothoracic vascular injury.
Comparisons of Methods To Detect Glaucomatous Optic Nerve Damage

Purpose: Various techniques of optic disc and nerve fiber layer evaluation may be used to detect structural glaucomatous damage. The authors compared several qualitative and quantitative methods to determine their relative sensitivities and specificities to detect the presence of glaucomatous visual field loss. Methods: Fifty-one healthy eyes, 169 ocular hypertensive eyes with normal visual fields, and 132 glaucomatous eyes with early visual field defects were evaluated with qualitative and quantitative measures of structural damage to the optic nerve and nerve fiber layer. Qualitative evaluations were performed by three experienced masked observers who independently graded stereoscopic color disc and monochromatic nerve fiber layer photographs. Quantitative measurements of disc rim area and nerve fiber layer height were made with digitized image analysis of videographic images. Manual planimetric measurements of disc rim area were made from enlarged prints of stereoscopic optic disc photographs. Diagnostic precision was defined as the total proportion of correct diagnoses for the presence or absence of visual field loss. Results: The diagnostic precision of results of a quantitative disc examination (81%) was greater than those of a qualitative nerve fiber layer examination (75%). Quantitative nerve fiber height measurement had the highest sensitivity rate (73%) and results of the qualitative disc examination had the highest specificity rate (87%) of the methods tested. Conclusion: The diagnostic precision of disc evaluation was superior to other methods, including nerve fiber layer examination, in correctly determining the presence of structural glaucomatous damage at the early visual field loss stage.
DDAVP: does the drug have a direct effect on the vessel wall?

Evidence is presented that 1-deamino-8-d-arginine vasopressin (DDAVP), a vasopressin analog, has a direct effect on isolated vessel segments. The most significant finding is increased platelet adhesion and spreading at injury sites. An isologous human umbilical vein perfusion model was used to compare effects of DDAVP with those of epinephrine or zero drug controls. Scanning electron microscopy, in conjunction with morphometry, permitted quantification of platelet adhesion to subendothelium exposed by minimal injury in the model. In addition, umbilical vein effluents were tested for levels of factor VIII moieties (F VIII:C, F VIII:RAg, F VIII:RCof) and the prostanoids, 6 keto PGF1α (stable metabolite of prostacyclin) and TXB2 (stable metabolite of thromboxane A2. Only F VIII:C from DDAVP treated segments was significantly (p < 0.01) changed from controls.
Does Rising Income Bring Integration? New Results for Blacks, Hispanics, and Asians in 1990

Abstract In this paper we update earlier work on racial and ethnic segregation by income to test assertions made by some observers that segregation is now largely a matter of class rather than race. Using the Summary Tape Files of the 1990 Census of Population, we measure the segregation of Blacks, Hispanics, and Asians within four categories of income: poor, lower middle class, upper middle class, and affluent. For all metropolitan areas containing at least 5000 members of the group in question, we compute indices of dissimilarity and interaction between minority members of a certain income and Whites of all income, thus measuring the extent of overall racial/ethnic segregation by social class. We find that Black residential segregation persists at high levels across all income levels, and that the gap between Blacks and other minority groups actually increases as income rises.
Imagined spatial transformation of one's body.

This study examined two related phenomena: (a) the judgment of whether a human body part belongs to the left or right half of the body and (b) the imagined spatial transformation of one's body. In three experiments, observers made left-right judgments of a part of a body whose orientation differed from their own by a rotation about one of 13 axes. To do so, they imagined themselves passing to the orientation of the stimulus. Time for (a) left-right judgments and (b) accompanying imagined spatial transformations depended on the extent of the orientation difference (OD) between the observer and stimulus. More important, time for phenomena (a) and (b) depended strongly, and in the same way, on the direction of OD. Further results showed that the rate of imagined spatial transformations can vary strongly for different axes and directions of rotation about an axis. These and other results (e.g., Parsons, 1987a) suggest that temporal and kinematic properties of imagined spatial transformations are more object-specific than could be previously assumed.
Expression and regulatory function of the transcription factor Sp1 in the uterine endometrium at early pregnancy: implications for epithelial phenotype.

Abstract The uterus during early pregnancy synthesizes a complex array of signaling molecules with specific spatial and temporal modes of expression and which are critical for embryo implantation and subsequent development. The mechanism(s) underlying the differential pattern of synthesis of these pregnancy-associated proteins is not understood very well. The present study evaluated the expression and trans-activation potential of the transcription factor Sp1 in the early pregnancy porcine endometrium to determine its temporal and functional association with the endometrial epithelial-specific genes encoding the transplacental iron-transport protein uteroferrin (UF) and an Sp-family member, basic transcription element-binding (BTEB) protein. Two identical Sp1 clones (717 bp) were isolated from a porcine endometrial cDNA library by polymerase chain reaction (PCR). The nucleotide sequence of these clones encodes a partial protein sequence of 238 amino acids encompassing the Zn-finger region and had significant identities with the corresponding regions in the rat and human proteins. By using a specific antibody raised against human Sp1, porcine endometrial Sp1 was found to exhibit a molecular weight of 110 kDa, was localized predominantly in the nuclei of glandular and luminal epithelial cells, and appeared to exist as a phosphorylated protein. Northern blot analysis demonstrated three distinct size transcripts of approximately 3.5, 5, and 8 kb for endometrial Sp1. The expression of Sp1 mRNA and protein, determined by RT-PCR and by its ability to bind Sp1 consensus motif in gel mobility shift assays, respectively, overlapped with, but did not parallel that of UF mRNA during early pregnancy. The effect of increased Sp1 expression on UF gene promoter activity was examined using a human Sp1 expression vector that was transiently transfected into primary cultures of pig endometrial glandular epithelial cells. Sp1 increased (P
Synthesis and Crystal Structures of the Mixed Ligand Coordination Polymers [Co2(N3)2(BZA)4(H2O)]·EtOH, Cu(N3)(BZA)2(H2O), and Cu(N3)(SUCC)(H2O)2 (N3 = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, BZA = benzoate, and SUCC = succinate)

The coordination polymers [Co2(N3)2(BZA)4(H2O)]·EtOH (1) and Cu(N3)(BZA)2(H2O) (2) were synthesized via room temperature diffusion layering using 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (N3), cobalt nitrate, copper acetate, and sodium benzoate (NaBZA). Compound 1 crystallizes in the monoclinic C2/c space group with unit cell dimensions of a = 15.8952(6) A, b = 13.9127(6) A, c = 24.2984(10) A, and β = 100.595(1)°. Compound 2 crystallizes in the orthorhombic Pna21 space group with unit cell dimensions of a = 22.211(3) A, b = 5.9543(7) A, and c = 18.038(2) A. The coordination polymer Cu(N3)(SUCC)(H2O)2 (3) was synthesized via room temperature diffusion layering using 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (N3), copper acetate, and sodium succinate (NaSUCC). Compound 3 crystallizes in the monoclinic P21/n space group with unit cell dimensions of a = 8.8148(7) A, b = 8.7643(7) A, c = 11.7758(9) A, and β = 102.6990(10)°. Three mixed ligand coordination polymers, [Co2(N3)2(BZA)4(H2O)]·EtOH (1), Cu(N3)(BZA)2(H2O) (2), and Cu(N3)(SUCC)(H2O)2 (3) were synthesized via room temperature diffusion layering using 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (3).
X‐ray diffractometry of airborne particulates deposited on membrane filters

Methods are considered for optimizing a conventional Bragg--Brentano X-ray powder diffractometer for the identification of crystalline phases in airborne particulates deposited on membrane filters. The instrumental parameters investigated include detector stepping increment and scan range, Kβ filtration, and the incident beam divergence slit width. Sample-related factors such as substrate material (cellulose ester, polycarbonate and polytetrafluoroethylene), off-axis displacement of the sample and X-ray induced specimen degradation were also studied. Scan times for sample deposits of several hundred μcm−2 are in the vicinity of 24 h with an 800 W tube. These times may be reduced substantially by one or more of the following modifications: rotating anode or synchrotron radiation source, energy-dispersive diffractometry, and Bragg--Brentano diffractometry with a position-sensitive gas detector.
Neurofilaments Consist of Distinct Populations That Can Be Distinguished by C-Terminal Phosphorylation, Bundling, and Axonal Transport Rate in Growing Axonal Neurites

We examined the steady-state distribution and axonal transport of neurofilament (NF) subunits within growing axonal neurites of NB2a/d1 cells. Ultrastructural analyses demonstrated a longitudinally oriented “bundle” of closely apposed NFs that was surrounded by more widely spaced individual NFs. NF bundles were recovered during fractionation and could be isolated from individual NFs by sedimentation through sucrose. Immunoreactivity toward the restrictive C-terminal phospho-dependent antibody RT97 was significantly more prominent on bundled than on individual NFs. Microinjected biotinylated NF subunits, GFP-tagged NF subunits expressed after transfection, and radiolabeled endogenous subunits all associated with individual NFs before they associated with bundled NFs. Biotinylated and GFP-tagged NF subunits did not accumulate uniformly along bundled NFs; they initially appeared within the proximal portion of the NF bundle and only subsequently were observed along the entire length of bundled NFs. These findings demonstrate that axonal NFs are not homogeneous but, rather, consist of distinct populations. One of these is characterized by less extensive C-terminal phosphorylation and a relative lack of NF–NF interactions. The other is characterized by more extensive C-terminal NF phosphorylation and increased NF–NF interactions and either undergoes markedly slower axonal transport or does not transport and undergoes turnover via subunit and/or filament exchange with individual NFs. Inhibition of phosphatase activities increased NF–NF interactions within living cells. These findings collectively suggest that C-terminal phosphorylation and NF–NF interactions are responsible for slowing NF axonal transport.