cssi/SciSciGPT-SciSciNet huggingface dataset:
Responses of thin fiber muscle afferents to contraction are greater in ligated than in freely perfused rats

Previous evidence has shown that ligating the femoral artery for 72 hours resulted in an exaggerated exercise pressor reflex. Nevertheless, electrophysiological evidence concerning the afferent arm of the reflex that is supportive of this exaggeration is lacking. Consequently, in decerebrated rats whose femoral arteries were either freely perfused or ligated for 72 hours, we compared the responses of thin fiber (i.e., group III & IV) muscle afferents to static contraction of the hindlimb muscles. We found that contraction in freely perfused rats increased thin fiber afferent activity (mean conduction velocity: 3.8±0.5 m/s) from 0.3±0.1 imp/s to 0.8±0.2 imp/s (n=26; p<0.05). In contrast, in ligated rats contraction increased afferent activity (mean conduction velocity: 3.4±0.6 m/s) from 0.4±0.1 imp/s to 1.4±0.1 imp/s (n=22; p<0.05). The contraction induced increase in thin fiber afferent activity was significantly greater in ligated rats than that in freely perfused rats (p<0.05). Stretch stimulated 12 of ...
The primal scene in cross-species and cross-cultural perspectives

A review of cross‐species and cross‐cultural research suggests that, throughout most of human behavioral evolution, children may have been enlightened as to the facts of life by observing parental ...
Uncertain Property Rights and Agricultural Production: Evidence from Post-Gold-Rush California

This paper uses data from California in 1860, a period in which property rights were uncertain, to investigate the relationship between the certainty of property rights and agricultural production. The negative effect of uncertain property rights on farm values, crop production, and wheat productions was large. For example, crop values for preemptors, who had more uncertain property rights than other farmers, were 22-38 percent lower than other farmers. This is consistent with contemporary discussion of the period, which linked uncertain property rights to low investment in the land and the use of short season crops. Less obviously, the mix of products was also significantly affected. Farmers with less secure property rights produced less as measured by crop value than similar farmers with more secure property rights, but owned similar amounts of livestock, presumably because it was mobile. In aggregate, uncertainty depressed the value of crop output by 13-20 percent. The results have implications for understanding the historical development of agriculture in the United States, since squatting on agricultural land was prevalent throughout the United States, and for understanding agriculture in the Third World, since uncertain property rights in agricultural land are still an issue today.
22 Applications of Yeast in the Discovery of Human Gene Function

Publisher Summary This chapter describes the applications of yeast in the discovery of human gene function. The convenience of handling and the ease of both classical and recombinant genetic manipulation have made yeast Saccharornyces cerevisae an invaluable model system in which both metabolic pathways and fundamental cellular processes, such as the cell cycle, DNA repair, transcription, translation, and protein secretion, can be dissected. Subsequent analysis of these pathways in higher eukaryotes has demonstrated that, despite a large evolutionary distance, yeast and humans exhibit a remarkable conservation of gene function. A consequence of this conservation is the ability to identify the functional homolog (ortholog) of a yeast gene from another eukaryote. The chapter describes approaches used to identify human homologs of a yeast gene by database homology searching and yeast genetic screens suitable for the functional isolation of human genes that lack a counterpart in yeast. The analysis of the human gene function by comparative yeast genomics is presented in the chapter. It also discusses the identification of human genes by genetic selection in yeast.
Thyroid hormones and the interrelationship of cortisol and prolactin: influence of prolonged, exhaustive exercise.

Wstep: Celem niniejszego badania bylo określenie wplywu dlugotrwalego, wyczerpującego wysilku fizycznego na: (1) stezenia wybranych hormonow tarczycy i (2) wspolzalezności miedzy wydzielaniem kortyzolu i prolaktyny w odpowiedzi na cwiczenia a stezeniami hormonow tarczycy. Material i metody: Zdrowe, wytrenowane osoby (n = 22) cwiczyly na biezni pochylej ze zwyklą dla siebie intensywnością określona na podstawie progu wentylacyjnego do momentu, kiedy poczuly zmeczenie (84,8 ± 3,8 min). Probki krwi pobrano przed rozpoczeciem cwiczen, kiedy badane osoby byly wypoczete (BL, baseline ), a nastepnie w momencie, gdy nastąpilo wyczerpanie po wysilku (EXH, exhanstion ), po 30-, 60-, i 90-minutowym odpoczynku i 24 godziny po zakonczeniu cwiczen (24 hR). Oznaczono stezenia wolnej T 3 (fT 3 ), wolnej T 4 (fT 4 ), hormonu tyreotropowego (TSH, thyroid stimulating hormone ), prolaktyny i kortyzolu. Wyniki: W analizie ANOVA dla powtarzalnych pomiarow wykazano, ze stezenia wszystkich hormonow byly podwyzszone w fazie EXH (p baseline ). Po 30- i 60-minutowym odpoczynku stezenia hormonow tarczycy zmniejszyly sie do wartości wyjściowych (p > 0,05); jednak stezenia kortyzolu i prolaktyny nadal byly wyzsze niz przed wysilkiem (BL) (p 0,05) od poziomu BL. Po 24 godzinach odpoczynku (24 hR) stezenia kortyzolu, fT 3 i TSH byly nizsze niz wartości BL (p 3 po 24 godzinach byly związane w sposob statystycznie istotny (rs = -0,51, p Wnioski: Wyniki uzyskane w niniejszym badaniu sugerują, ze po wyczerpujących cwiczeniach (1) nastepuje zmniejszenie wydzielania wybranych hormonow tarczycy po 24 godzinach wypoczynku, a zmiany te są zalezne od stezenia kortyzolu, (2) zwiekszenie stezenia prolaktyny spowodowane wysilkiem jest proporcjonalne do wzrostu wydzielania TSH.
Monitoring Automation Failures: Effects of Single and Multi-Adaptive Function Allocation

Adaptive function allocation has been proposed to allow the advantages of task automation to be realized without some of the disadvantages of “static” automation. However, few empirical studies of the efficacy of adaptive allocation have been reported. The effects of adaptive function allocation on monitoring for automation failure during multi-task flight simulation were examined in two experiments. The first study examined the use of two methods of adaptive function allocation as a possible counter-measure to automation-induced monitoring problems. Subjects were required to perform a tracking and fuel management task while monitoring an automated system monitoring task for possible failures. For the “model-based” and “performance-based” adaptive groups, a single 10-minute block of fully manual performance on the monitoring task was allocated to subjects in the middle of a session. For the control group system monitoring was automated throughout all sessions. All three groups had low probabilities of det...
An Econometric Analysis of Patient Flows in the Cardiac Intensive Care Unit

This paper explores the rationing of bed capacity in a cardiac intensive care unit (ICU). We find that the length of stay for patients admitted to the ICU is influenced by the occupancy level of the ICU. In particular, a patient is likely to be discharged early when the occupancy in the ICU is high. This in turn leads to an increased likelihood of the patient having to be readmitted to the ICU at a later time. Such “bounce-backs” have implications for the overall ICU effective capacity---an early discharge immediately frees up capacity, but at the risk of a (potentially much higher) capacity requirement when the patient needs to be readmitted. We analyze these capacity implications, shedding light on the question of whether an ICU should apply an aggressive discharge strategy or if it should follow the old quality slogan and “do it right the first time.” By comparing the total capacity usage for patients who were discharged early versus those who were not, we show that an aggressive discharge policy applied to patients with lower clinical severity levels frees up capacity in the ICU. However, we find that an increased number of readmissions of patients with high clinical severity levels occur when the ICU is capacity constrained, thereby effectively reducing peak bed capacity.
Recycled path routing in mobile ad hoc networks

In mobile ad hoc networks, many routing algorithms rely on some form of flooding to accomplish the route discovery process. Flooding, however, consumes many valuable network resources such as time, bandwidth, and power. Most current routing schemes expire valid routes after a time period to account for nodal movement. This paper proposes a new route discovery method, called recycled path routing (RPR), which directs broadcasts toward the destination node even in the absence of location information. The recycled path routing scheme reduces the search space for the destination node by implementing an expired route cache that is utilized by each node in the network. Routes are added to the expired route cache as they expire from the active route cache and remain there until some time interval has passed or a new route has been discovered. Since these expired routes can provide valuable insight into finding new routes, RPR uses them to direct broadcasts toward the destination node. RPR can save a significant quantity of valuable network resources because only nodes near the optimal path will rebroadcast route requests.
The complexity of hierarchical systems

We introduce a procedure for coarse graining a given hierarchical structure and show how it leads to an effective saturation of the complexity value with increasing number of lower levels. Secondly, we verify that this coarse grained measure has the property of isolating the most diverse trees as the ones with maximal complexity. As a corollary, we cast the dynamical measure of complexity of Bachas and Huberman in terms of purely static properties of trees representing ultradiffusion. We also discuss the differences between the coarse-grained measure of complexity and that provided by relaxation processes.
Signal detection theory approach to the multiple parallel moving targets problem

Abstract The problem of detection and line location estimation of multiple, parallel, dim, moving targets, such as the ones typically encountered when a geostationary satellite is tracking targets, is studied under the framework of signal detection theory. Part I of the paper considers two-dimensional data (or one frame of an image) and Part II considers an additional third dimension representing time. Optimal processors are derived for varying degrees of uncertainty in the data for the detection of parallel targets. The uncertainties include uncertainty in the knowledge of orientation, location, number, and direction of arrival of the targets. Performance of the optimal processors is presented in the form of Receiver Operating Characteristic (ROC) curves and compared, in Part I, with the Hough transform. The optimal 2-D processors perform better than the Hough transform under all cases of uncertainties. Likelihood-ratio-based optimal estimation algorithms resolve the location of targets under severe noise conditions. In Part II, ROCs for the optimal 3-D processors are compared with both 2-D optimal processors and the Hough transform that use the projected data. Simulation results indicate that substantial gains in performance can be achieved by processing the 3-D data directly instead of first projecting and optimally processing in 2-D. It is observed that the computational burden in optimally processing the 3-D data sequentially is comparable to the conventional techniques involving projection and the Hough transform.
Conserved Regulation of MAP Kinase Expression by PUF RNA-Binding Proteins

Mitogen-activated protein kinase (MAPK) and PUF (for Pumilio and FBF [fem-3 binding factor]) RNA-binding proteins control many cellular processes critical for animal development and tissue homeostasis. In the present work, we report that PUF proteins act directly on MAPK/ERK-encoding mRNAs to downregulate their expression in both the Caenorhabditis elegans germline and human embryonic stem cells. In C. elegans, FBF/PUF binds regulatory elements in the mpk-1 3′ untranslated region (3′ UTR) and coprecipitates with mpk-1 mRNA; moreover, mpk-1 expression increases dramatically in FBF mutants. In human embryonic stem cells, PUM2/PUF binds 3′UTR elements in both Erk2 and p38α mRNAs, and PUM2 represses reporter constructs carrying either Erk2 or p38α 3′ UTRs. Therefore, the PUF control of MAPK expression is conserved. Its biological function was explored in nematodes, where FBF promotes the self-renewal of germline stem cells, and MPK-1 promotes oocyte maturation and germ cell apoptosis. We found that FBF acts redundantly with LIP-1, the C. elegans homolog of MAPK phosphatase (MKP), to restrict MAPK activity and prevent apoptosis. In mammals, activated MAPK can promote apoptosis of cancer cells and restrict stem cell self-renewal, and MKP is upregulated in cancer cells. We propose that the dual negative regulation of MAPK by both PUF repression and MKP inhibition may be a conserved mechanism that influences both stem cell maintenance and tumor progression.
Cell-cycle response to nutrient starvation in two phytoplankton species, Thalassiosira weissflogii and Hymenomonas carterae

The influence of nutrient deprivation on cell-cycle progression was examined in two phytoplankton species, the diatom Thalassiosira weissflogii (actin) and the coccolithophorid Hymenomonas carterae (cocco II). The diatom was starved for nitrogen, silicon or both, whereas only nitrogen limitation was examined in H. carterae. In both species, nitrogen-starved cells were arrested in the early part of the cell cycle (G1 phase). In the diatom, silicon-starvation arrested cells in late G1 phase and also in the last part of the cell cycle (G2+M). In all cases, cell-cycle arrest could be reversed by addition of fresh medium, but cell-cycling times during the first generation were increased in comparison to those in nutrient replete, steady-state growth conditions. These results supply evidence for simultaneous dual-nutrient limitation of population growth and provide a mechanistic interpretation for the division patterns observed in cultures where nutrients are supplied periodically.
QT dispersion and viable myocardium in patients with prior myocardial infarction and severe left ventricular dysfunction.

Background: QT dispersion (QTd) has been found to correlate to the amount of viable myocardium in patients with Q-wave myocardial infarction and well-preserved LV function. However, this relationship is unknown in patients with severe left ventricular dysfunction. Methods: Thirty-four patients with prior large myocardial infarction and severe left ventricular dysfunction underwent Tc-99m sestamibi single photon emission cardiac tomography (SPECT) and F-18 fluorodeoxyglucose (FDG) SPECT. Viability was defined as a defect relative count density (DCD) of at least 20% greater on FDG SPECT. QTd, corrected QT dispersion (QTcd), and QT coefficient of variation (cv) in patients with viable myocardium was compared to those without viable mvocardium in the infarct area. Results: Thirteen patients were excluded from analysis for poor FDG images or inadequate ECG tracings. Of the remaining patients, 10 (48%) were found to have viability on FDG SPECT. QTd, QTcd, and QTcv in patients with viability were: 58 ± 22 ms, 61 ± 23 ms, and 4.81 ± 1.76%, respectively, which did not differ significantly from those in patients without viability (QTd = 56 ± 14 ms, QTcd = 70 ± 16 ms and Qtcv = 5.06 ± 1.20% (P = NS]). Moreover, neither FDG defect size, nor LVEF correlated with QTd. Conclusions: This study indicates no relationship between QTd and viability in patients with myocardial infarction and severe left ventricular dysfunction. A.N.E. 2002;7(1):53–59
A new synthesis of diethyl β-ketoadipate

Abstract A new and reliable synthesis of diethyl β-ketoadipate (Ia) is described, in which the ethoxymagnesio derivative of ethyl t-butyl malonate is condensed with β-carbethoxypropionyl chloride to the triester (VI, R = Et), which is decomposed by refluxing under vacuum in the presence of added acid. Distillation gives pure diethyl β-ketoadipate (Ia). Previously described procedures for the preparation of Ia are shown to give impure products.
Defending the white race: White male faculty opposition to a "white racism" course

Abstract The structures and processes of curriculum censorship are a microcosm of the racial organization and dynamics of America and other modern societies. They offer valuable insights into how the issue of systemic white racism is kept off organizational agendas. Whether successful or unsuccessful, censorship efforts typically become visible only in those rare instances when they are challenged publicly. In this paper arguments made against and for an intensely opposed “White Racism” course are examined to delineate the relationship between power, voice, and social change. This curriculum conflict is the analytical vehicle through which we explore the role of race-defensive denial in the persistence of systemic white racism. This case study also reveals effective ways of overcoming such denial and placing white racism at the center of social discourse.
The consistency of weanling and adult rats

It was hypothesized that the degree of association between emotionality test scores on adjacent trials is less for weanling than adult rats. The hypothesis received strong, slight, and no support for the emerge-from-home-cage, open field, and timidity emotionality variables, respectively.
Fetal male masculinization in control and prenatally stressed rats

The present experiments were designed to test the hypothesis that males in utero masculinize the development of other males. This effect was examined during fetal development in males from control and prenatally stressed rats. A code identified the number of cervical-flanking males between the target male and the cervical end of the uterus. The male parameters morphology (anogenital distance) and body, adrenal, and testis weights were recorded on the eighteenth and twentieth gestational days and categorized by the cervical-flanking male classification. At Day 18, control fetuses with two cervical-flanking males in utero displayed significantly greater anogenital distance values than did males with no cervical-flanking male. At Day 20, control fetuses with two cervical-flanking males had testicular weights significantly greater than those of fetuses with one or zero cervical positioned male. Prenatal stress markedly impaired male fetal development at gestational Days 18 and 20 while suppressing the cervical-flanking male effect. These results confirm and extend previous data that indicate: (a) prenatal stress disrupts normal fetal development, resulting in long-term changes; and (b) androgens via a cervical-flanking blood-flow mechanism influence littermate morphology and sexual development during the prenatal period. Our findings also demonstrate that a general masculinizing effect could not be made across the measured male parameters since the effect of males positioned at the cervical-flanking region in utero appears to be dependent upon maternal sources of variance. Finally, androgens prenatally have an apparent positive interaction with somatic growth.
Current corrosion protection problems

Abstract Corrosion is the reaction of a material with its environment, and it may lead to a measurable change in the material and to corrosion damage. In the industrial countries, losses due to corrosion amount to about 4% of gross national product. The object of all research work in this area is to achieve the most effective corrosion protection possible, in order to minimize costs and losses.
Massive Atenolol, Lisinopril, and Chlorthalidone Overdose Treated with Endoscopic Decontamination, Hemodialysis, Impella Percutaneous Left Ventricular Assist Device, and ECMO

Background Overdose of cardiovascular medications is increasingly associated with morbidity and mortality. We present a case of substantial atenolol, chlorthalidone, and lisinopril overdose treated by multiple modalities with an excellent outcome.
Self-Reporting and the Design of Policies for Regulating Stochastic Pollution

Abstract Existing environmental regulations frequently require firms to self-report their compliance status to regulatory agencies. Using a principal-agent framework, I derive and compare incentive-compatible regulatory policies with and without self-reporting. I find the firm needs to be audited less often when self-reporting is required, but punished more often. The sign and magnitude of the gains from self-reporting depend on the relative size of audit and sanction costs, the accuracy of the regulator′s monitoring technology, and the desired level of abatement effort.
Structural biology of proline catabolism

The proline catabolic enzymes proline dehydrogenase and Δ1-pyrroline-5-carboxylate dehydrogenase catalyze the 4-electron oxidation of proline to glutamate. These enzymes play important roles in cellular redox control, superoxide generation, apoptosis and cancer. In some bacteria, the two enzymes are fused into the bifunctional enzyme, proline utilization A. Here we review the three-dimensional structural information that is currently available for proline catabolic enzymes. Crystal structures have been determined for bacterial monofunctional proline dehydrogenase and Δ1-pyrroline-5-carboxylate dehydrogenase, as well as the proline dehydrogenase and DNA-binding domains of proline utilization A. Some of the functional insights provided by analyses of these structures are discussed, including substrate recognition, catalytic mechanism, biochemical basis of inherited proline catabolic disorders and DNA recognition by proline utilization A.
Wind scatterometry and the status of the NASA scatterometer

The NASA Scatterometer (NSCAT) was launched in August 1996 aboard the Japanese Advanced Earth Observation System-I (ADEOS-I) as part of the NASA Earth Probes program. NSCAT is an active microwave remote sensor designed to measure winds over the ocean from space. NSCAT can measure vector (speed and direction) winds over 90% of the Earth's ice-free oceans every two days. Such data is important in weather prediction and air-sea interaction studies since winds modulate all air-sea fluxes. The Ku-band NSCAT is a follow-on to the Seasat scatterometer but has improved resolution and coverage. NSCAT is a Doppler scatterometer with 600 km wide swaths on either side of the nadir track. In comparison the C-band ERS-1/2 Active Microwave Instrument scatterometer system has only a single swath. A follow-on to NSCAT, known as SeaWinds, is in development and will be launched in 1999. The on-orbit performance of NSCAT is superb with initial data products delivered to the science team within two months of the start of data collection. This paper provides a brief overview of the NSCAT mission and its status and briefly discusses the results of the calibration and validation study and some new applications of NSCAT data.
Teacher Participation in Organizational Decisions

"... Where efficiency depends on continued coordination and interaction of persons, a deci sion produced by the group to be involved will almost always be superior to one produced by even the most capable of individuals."
Structure-based CoMFA and CoMSIA study of indolinone inhibitors of PDK1

Phosphoinositide-dependent protein kinase-1 (PDK1) is a Ser/Thr kinase which phosphorylates and activates members of the AGC kinase group known to control processes such as tumor cell growth, protection from apoptosis, and tumor angiogenesis. In this paper, CoMFA and CoMSIA studies were carried out on a training set of 56 conformationally rigid indolinone inhibitors of PDK1. Predictive 3D QSAR models, established using atom fit alignment rule based on crystallographic-bound conformation, had cross-validated (rcv2) values of 0.738 and 0.816 and non-cross-validated (rncv2) values of 0.912 and 0.949 for CoMFA and CoMSIA models, respectively. The predictive ability of the CoMFA and CoMSIA models was determined using a test set of 14 compounds, which gave predictive correlation coefficients (rpred2) of 0.865 and 0.837, respectively. Structure-based interpretation of the CoMFA and CoMSIA field properties provided further insights for the rational design of new PDK1 inhibitors.
Retention of transuranic and actinide elements and bismuth at the Oklo natural reactor, Gabon: Application of Eh—pH diagrams

Abstract Several tons of 239Pu and lesser amounts of 240Pu and 241Pu were produced during the 0.5 Ma lifetime of the Oklo natural reactor, Gabon, some 1.8 Ga ago. Production of Pu isotopes is evidenced by slight excesses of 235U in otherwise 235U-depleted U-rich zones as well as by even slighter excesses of 232Th and 209Bi in the same zones. The low-grade ore, unaffected by nuclear reactions, contains very little Bi and Th, and U possesses a normal isotopic composition. The 241Pu-produced Bi-excess demands that 241Am, 237Np and other members of the 241Pu decay chain must not have migrated, since loss of any member from the 241Pu decay chain would prevent the Bi excesses from accumulating in the high-grade ore zones. Eh—pH diagrams for all species of importance indicate the following: Po is retained as the native metal in the Eh—pH range of interest, whereas Pu and Np are retained as PuO2 and NpO2, respectively. Am is probably retained as Am(OH)3 or as an (Eu,Am)2(CO3)3 species. The field of Bi2S3 is wide enough to prevent migration even under slightly oxidizing conditions. Collectively, these data argue for the retention of Pu, Am, Np, U, Po and Bi at Oklo and suggest that geologic sites elsewhere should be suitable for waste isolation.
Zombie businesses: How to learn from their mistakes

Organizations that exude self-confidence, pride, and unrelenting team spirit can become delusional.
Loading tools to machines in flexible manufacturing systems

Abstract This paper presents two models for loading tools to machines in a flexible manufacturing system (FMS) environment. Heuristic algorithms associated with the models are presented and discussed. The performance of each of the proposed algorithms is evaluated by testing on two hypothetical FMSs.
Discrete Molecular Dynamics simulations on hexameric amyloid-β (1-40) and (1-42) models

Aggregation of amyloid-β peptides (Aβ) may play a pivotal role in neurotoxicity of Alzheimer's disease. Two major alloforms of Aβ are the 40-residue long Aβ40 and the 42-residue long Aβ42. Though Aβ42 has only two more residues at the end of C-terminus, Aβ40 and Aβ42 show different characteristics in early aggregation: Aβ40 aggregates to exist from monomers up to tetramers while Aβ42 exists from monomers to hexamers, dodecamers, or even octadecamers. However, the molecular mechanism of the different aggregation between Aβ40 and Aβ42 is not clearly understood since their oligomeric structures are not available from experiments due to their meta-stable characteristics. Here, we simulated nine hexameric Aβ40 and nine hexameric Aβ42 models with Discrete Molecular Dynamics (Discrete MD). The hydrophobic core of these models is a six-stranded β-barrel formed by residues 30-40 that has three-fold symmetry about its axis. This core is shielded from water by residues 1-28. The models differ by the relative positions of the core β strands, and whether the other segments surrounding the core contain α helices or β-strands. The potential energy of Aβ40 measured by Miyazawa-Jernigan interaction matrix were considerably lower than the potential energy of Aβ42 in all of 18 models tested, probably because more hydrophobic residues are exposed to water in theAβ42 models. In two of nine models of Aβ42, dangling hydrophobic β-strands emerged on the surface. This implies that the association of these hexamers may be possible, which could lead to the formation of larger assemblies.
Gene regulation of ENaC subunits by serum- and glucocorticoid-inducible kinase-1

Aldosterone is a key regulator of epithelial Na+ channels (ENaC) in renal cortical collecting ducts (CCD). The goal of this study was to examine whether serum- and glucocorticoid-inducible kinase-1...
A laboratory exercise in comparative DNA analysis

This report describes a laboratory exercise that is used in an upper level biochemistry course at a small liberal arts college. The laboratory exercise was designed with three major learning objectives in mind. The first objective is that students learn how to isolate and purify plasmid DNA. The second is that they understand this process on a molecular level. Last, they analyze their DNA samples using a variety of biochemical and biophysical methods. By comparing and contrasting the results, they are to draw conclusions about which methods would be best under a given set of experimental conditions.
Increased levels of NAD(P)H: quinone oxidoreductase 1 (NQO1) in pancreatic tissues from smokers and pancreatic adenocarcinomas: A potential biomarker of early damage in the pancreas.

NAD(P)H:quinone oxidoreductase 1 (NQO1) is elevated in several human tumors. This study was conducted to determine whether increased levels of NQO1 expression also occur in human pancreatic tumor tissue, and to compare expression levels in nontumorous tissue from smokers with those in nonsmokers. The expression of NQO1 was examined in pancreatic tissue samples from 82 human donors. These samples included normal (n = 20), smokers (n = 25), pancreatitis (n = 7), and adenocarcinomas of the pancreas (n = 30). Genotyping for the C609T polymorphism in NQO1 by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis was also performed. Polymorphic variants were confirmed by automatic sequencing. Higher levels of NQO1 expression were demonstrated in pancreatic adenocarcinomas (0.831 ± 0.021) compared to those in nontumorous tissues from nonsmokers (0.139 ± 0.024). These high levels were also found in smokers (0.729 ± 0.167) and in pancreatitis tissues (0.923 ± 0.184). NQO1 activity was also higher in smokers (2.43 ± 0.61 nmol/min per mg protein) compared to nonsmokers (0.44 ± 0.05 nmol/min per mg protein; p < 0.05). No differences were found in genotype distribution and frequencies of the variant alleles between normal and cancer tissues in this relatively small sample pool. Seventy-five percent of the normal pancreatic tissues showed 609(C/C) and 25% 609(C/T). In pancreatic adenocarcinomas the frequency distribution was 65% C/C, 30% C/T and 5% T/T. The increased expression in noncancer pancreatic tissue from smokers and the fact that smoking is a moderate risk factor for pancreatic cancer suggest that NQO1 expression may be a good candidate as a biomarker for pancreatic cancer, especially in risk groups such as smokers.
(Nitrato-κO)oxido(5,10,15,20-tetra-phenyl-porphyrinato-κN)molybdenum(V) benzene solvate.

In the title compound, [Mo(C44H28N4)(NO3)O]·C6H6, the porphyrin ring is centrosymmetric. The Mo atom, oxide ion and nitrate ion are equally disordered over two sites, such that the Mo atom is displaced by 0.366 (1) A towards the oxide ion from the 24-atom mean plane of the porphyrin, and also makes a long Mo—O bond to a nitrate O atom. A centrosymmetric benzene solvent mol­ecule is situated between adjacent porphyrin mol­ecules.
Derivation and Left Ventricular Pressure Phase Plane Based Validation of a Time Dependent Isometric Crossbridge Attachment Model

Huxley’s crossbridge attachment model predicts tension (contractile force) development in isometric (fixed length) cells using constant attachment and detachment rates. Alternative models incorporating time-varying calcium concentrations are complex (coupled linear differential equations) and use time-dependent inputs (calcium, elastance, etc.) to model multiple states. We hypothesize that by incorporating the known significant rise and fall in intracellular calcium, via either an asymmetric damped function or a symmetric Gaussian function, into a time-varying, rather than constant, attachment rate function, the Huxley model prediction for tension (i.e., chamber pressure) in isovolumic (isometric) non-ejecting beats will improve. To test the hypothesis that the time-dependent model-predicted (TDM) pressure fits the in vivo isometric (isovolumic) LV pressure phase-plane (PPP) contour better than the constant attachment rate predicted pressure, we used the TDM to fit non-ejecting, premature ventricular contraction (PVC) PPP contours in 6 subjects. Conventional model fit was poor (relative error 74.0%±12.5%), while the asymmetric damped TDM rate function provided slight improvement relative to the conventional time-independent model (relative error 55.4%±9.8%). The symmetric Gaussian rate function TDM provided the best PPP fit to all non-ejecting beats tested (relative error 19.8%±4.8%). We conclude that approximating the lumped attachment rate via a time-varying, rather than constant, rate function generates a physiologically viable model of crossbridge behavior. The PPP provides the optimal arena for alternate mathematical formulation assessment of LVP contour prediction by time-dependent attachment rate functions and facilitates modeling of cardiac contraction and relaxation.
Experimental and clinical assessment of the adequacy of partial bypass in maintenance of spinal cord blood flow during operations on the thoracic aorta.

Abstract We studied both experimentally and clinically the efficacy of partial bypass techniques in maintaining spinal cord blood flow and physiological function during surgical procedures on the thoracoabdominal aorta. We attempted to define the level of distal aortic pressure required to safely ensure normal neurological function in the absence of critical intercostal occlusion. Six dogs underwent left thoracotomy with baseline measurements of spinal cord blood flow and spinal cord impulse conduction (somatosensory evoked potentials). Following exclusion of the entire descending thoracic aorta from the left subclavian artery to the T-13 level, partial left atrium-femoral artery bypass was instituted, and baseline levels of proximal and distal aortic pressure were maintained during a 30-minute stabilization period. Mean distal aortic pressure then was progressively altered at 30-minute intervals to 100, 70, and 40 mm Hg. Measurements of spinal cord blood flow and somatosensory evoked potential were repeated at the end of each interval for comparison with baseline. No significant changes in spinal cord blood flow or somatosensory evoked potential were observed in any animal with a distal aortic pressure greater than or equal to 70 mm Hg. With a pressure of 40 mm Hg, normal flow and somatosensory evoked potentials were maintained in 5 of the 6 dogs. Loss of somatosensory evoked potential, with simultaneous loss of spinal cord blood flow at the T-6 level, occurred in 1 dog. Restoration of distal aortic pressure to 70 mm Hg in all animals resulted in immediate return of somatosensory evoked potential. Loss of somatosensory evoked potential routinely occurred in animals with a distal aortic pressure less than 40 mm Hg. Clinically, 9 patients have undergone operation for lesions of the thoracoabdominal aorta using shunt or bypass techniques. Normal somatosensory evoked potentials were preserved in 7 patients with maintenance of adequate distal aortic pressure (greater than or equal to 60 mm Hg) without evidence of postoperative neurological deficit. Two patients showed hypotensive somatosensory evoked potential loss (distal aortic pressure less than 40 mm Hg). Prolonged distal hypotension (85 minutes of aortic cross-clamping) in the latter resulted in paraplegia. We conclude that maintenance of a distal aortic pressure greater than 60 to 70 mm Hg will uniformly preserve spinal cord blood flow in the absence of critical intercostal exclusion. Should distal aortic pressure be inadequate, early reversible changes in the somatosensory evoked potential will alert the surgeon. Failure to institute measures to reverse these changes may result in paraplegia.
Effects of the screened exchange interaction on the tunneling and Landau gaps in double quantum wells

A self-consistent screened Hartree-Fock calculation, combined with the Landau quantization of in-plane electron motion, is performed to find the eigenstates and eigenenergies of electrons in double quantum wells. This theory is applicable to both the low and strong magnetic-field cases. The screened exchange interaction is calculated by using a generalized Thomas-Fermi screening model. The approximately linear increase of the tunneling gap at low magnetic fields (B9 T) and the switching of the ground state between the tunneling-split first Landau levels are seen and explained as a result of the increase of screening effects on the exchange interaction when both tunneling-split first Landau levels are filled. \textcopyright{} 1996 The American Physical Society.
Solidification Map of a Nickel-Base Alloy

The solidification behavior of the advanced nickel-base alloys, such as Inconel® Alloy 690, is important for understanding their microstructure, properties, and eventual service behavior in nuclear power plant components. Here, an experimental and theoretical program of research is undertaken with the aim of developing a quantitative understanding of the solidification behavior under a wide range of temperature gradients and solidification growth rates. The temperature gradient and solidification rates vary spatially by several orders of magnitude during keyhole mode laser welding. Therefore, the solidification structure is experimentally characterized from microscopic examinations of the resulting fusion zones and correlated with fundamental solidification parameters to provide a widely applicable solidification map that can be employed for a broad range of solidification processes. The cell and secondary dendrite arm spacings are quantitatively correlated with cooling rates. An Alloy 690 solidification map, which illustrates the effect of temperature gradient and solidification rate on the morphology and scale of the solidification structures, is also presented.
Beryllium in marine pore waters: Geochemical and geochronological implications

DIAGENETIC remobilization and hydrothermal inputs have been invoked as possible explanations for the discrepancy between the theoretical and measured temporal decrease of the non-detrital 10Be/9Be ratio observed in sediments1. Remobilization is also consistent with water-column profiles of beryllium, which indicate a significant benthic flux from sediments2. To evaluate the impact of diagenetic recycling on the beryllium isotopic composition of marine waters and the effects of this process on the beryllium geochronometer, we have analysed the9.Be content of interstitial waters from different environments. Here we report the first pore-water profiles for 9Be in oxic and suboxic pore waters as well as some preliminary results from hydrothermal sediments collected in the Guaymas Basin. Our results suggest that the use of the beryllium isotopes as a geochronometer is not affected either by sedimentary diagenesis at oxic and suboxic sites or by input of hydrothermally derived 9Be more than a few kilometres from vent sites.
Volcanic triggering of late Pliocene glaciation: evidence from the flux of volcanic glass and ice-rafted debris to the North Pacific Ocean

Abstract Mass accumulation rates (MAR) of different components of North Pacific deep-sea sediment provide detailed information about the timing of the onset of major Northern Hemisphere glaciation that occurred at 2.65 Ma. An increase in explosive volcanism in the Kamchatka–Kurile and Aleutian arcs occurred at this same time, suggesting a link between volcanism and glaciation. Sediments recovered by piston-coring techniques during ODP Leg 145 provide a unique opportunity to undertake a detailed test of this possibility. Here we use volcanic glass as a proxy for explosive volcanism and ice-rafted debris (IRD) as a proxy for glaciation. The MAR of both glass and IRD increase markedly at 2.65 Ma. Further, the flux of the volcanic glass increased just prior to the flux of ice-rafted material, suggesting that the cooling resulting from explosive volcanic eruptions may have been the ultimate trigger for the mid-Pliocene glacial intensification.
Gαq reduces cAMP production by decreasing Gαs protein abundance

The heterotrimeric guanine nucleotide-binding protein Gαq transduces signals from heptahelical transmembrane receptors (e.g., α1-adrenergic, endothelin 1A, and angiotensin II) to stimulate generation of inositol-1,4,5-trisphosphate and diacylglycerol. In addition, Gαq decreases cAMP production, through unknown mechanisms, and thus affects physiological responsiveness of cardiac myocytes and other cells. Here, we provide evidence that Gαq expression increases Gαs ubiquitination, decreases Gαs protein content, and impairs basal and β1-adrenergic receptor-stimulated cAMP production. These biochemical and functional changes are associated with Akt activation. Expression of constitutively active Akt also decreases Gαs protein content and inhibits basal and β1-adrenergic receptor-stimulated cAMP production. Akt knockdown inhibits Gαq-induced reduction of Gαs protein. In addition, MDM2, an E3 ubiquitin ligase, binds Gαs and promotes its degradation. Therefore, increased expression of Gαq decreases cAMP production through Akt-mediated Gαs protein ubiquitination and proteasomal degradation.
Chromium Supplementation for Menstrual Cycle-Related Mood Symptoms

ABSTRACTBackground: Premenstrual dysphoric disorder (PMDD) afflicts ∼7% of reproductive-age women resulting in impaired relationships, diminished overall quality of life, and disability-adjusted life years lost on par with other major psychiatric disorders. Response to pharmacological treatment is inadequate in ∼50% of women with PMDD. Objective: The goal of the present study is to evaluate the effects of a novel approach—short-term chromium supplementation—on menstrual cycle-related mood and physical symptoms. Methods: Five women were studied under single-blind conditions in a private clinical setting (2 of them were referred specifically for treatment-resistant menstrual-related symptoms); 6 women completed a double-blind crossover study of chromium plus placebo versus chromium plus sertraline in a university clinical research setting. Treatments were administered from mid-cycle to onset of menses in 1-month intervals. Symptom ratings were obtained by self-report, using daily symptom checklists, and by ...
An Analysis of Verbal Communication Patterns in High and Low Marital Adjustment Groups

A 12-category coding system, the Intimate Negotiation Coding System (INCS), was used to analyze the verbal sequential processes of high marital adjustment couples and low marital adjustment couples. The results of Markov chain and Lag sequential analyses indicated that high marital adjustment interaction is primarily characterized by significant sequential patterns of confirming, socioemotional description, and instrumental questioning strategies. The low marital adjustment interaction is mainly characterized by unique reciprocal patterns of confront confront, confront defend, complain defend, and defend complain verbal interacts. It was also found that the verbal negotiation processes of low-adjusted marital couples are more highly structured or patterned (up to Lag 10) than the sequential interaction of high-adjusted marital couples.
Cognitive Processes, Social Mores, and the Accumulation of Data Program Evaluation and the Status Quo

Distortion and selective disclosure limit data available to program evaluators, producing a bias that tends to maintain the status quo. Paradoxically, attempts to objectify, regulate, or depersonalize the production of data only increase the potential for distortion. A reliance on the data produced by science is not necessarily a solution. Social science tends to be a self-legitimizing specialty that forces our understanding of social situations into historically accepted categories and relationships without specifying methods for testing the validity of these findings. An awareness of status quo tendencies raises prob lems for evaluators interested in innovation and change.
Modeling of junction capacitances of graded base heterojunction bipolar transistors

Abstract Capacitance models for emitter-base and collector-base junctions of graded base heterojunction bipolar transistors (HBTs) are developed. Effects of base grading on potential barriers, space-charge region (SCR) boundaries, and emitter-base and collector-base junction capacitances are investigated. The emitter-base capacitance is divided into depletion capacitance and capacitance resulting from the mobile carriers in the SCR. To obtain a closed-form solution for the capacitance, intrinsic potential is assumed to be piecewise linear. For the collector-base capacitance, depletion approximation is employed, since the junction is usually reverse-biased in normal operation. It is demonstrated that the present model is quite consistent with the measured data.
Epicardial ischemia as delineated with epicardial S-T segment mapping and nicotinamide adenine dinucleotide (NADH) fluorescence photography

In isolated rabbit hearts with an experimental coronary arterial occlusion, epicardial ischemia was identified by reduced nicotinamide adenine dinucleotide (NADH) fluorescence photography, a technique that detects areas of myocardial anoxia. Epicardial S-T segment mapping was performed to evaluate the S-T segment changes across an ischemic border defined by NADH fluorescence. After S-T segment mapping and perfusion with a fluorescein dye, serial selections of the hearts revealed that the ischemic area was transmural and and the border was nearly perpendicular to the epicardial surface. As the epicardial ischemic border was approached, S-T segment elevation was first detected 3.3 mm outside the ischemic border, and increased over a transition zone 7 mm wide. S-T segment negativity was not detected immediately outside the ischemic border. It is concluded from these studies that S-T segment changes give relatively imprecise definition of an ischemic border, and that S-T segment changes across an ischemic border are not consistent with those predicted by solid angle analysis.
Dewetting Conditions for Ionic Liquid Films: Novel Features of the Stability Diagram

Abstract Dewetting conditions formulated for charge-neutralized liquid films (Mitlin, V. S., J. Colloid Interface Sci.156, 491, 1993) are generalized for ionic liquid films. Free energy of the film, accounting for the van der Waals attraction, Born repulsion, electrostatic forces, and gravitation, is considered. It is shown that electrostatic contribution yields novel features in dewetting descriptions. Particularly for physically reasonable values of the parameters, the free energy may have a two-double-tangent form, which yields several thickness intervals of instability and metastability for the film. Film stability diagrams are presented. Analytical expressions for the lower boundaries of stability and metastability are obtained at large values of electrostatic force. The importance of metastable states in dewetting descriptions is emphasized.