cssi/SciSciGPT-SciSciNet huggingface dataset:
Experimental Investigation of Proppant Flowback Phenomena Using a Large Scale Fracturing Simulator

This paper evaluates the maximum flow rate before the sand production initiates while flowing back a reservoir after the hydraulic fracturing treatment. The experiments are performed in a high pressure slot which simulates a fracture. The slot is a parallel plate device, which is 7 ft high and 9 1/3 ft long with provisions for varying fracture gap width. The slot is filled with proppant to simulate a propped fracture, then, the closure pressure is applied with 12 actuators to simulate confining pressure on the proppant pack. Water is pumped into the slot to simulate flowing back of the fracturing fluid. The water flow rate is varied till the proppant pack destabilizes, and the sand production begins. The sand distribution is observed in the fracture with a vision system. The experimental results show that the critical water flowback rate decreases as the closure pressure increases, or when the fracture gap width increases. However, the sand-free maximum water flow rate increases as the sand size increases for a given fracture gap width. Lastly, the cumulative sand production decreases as the closure stress decreases at a particular flow rate. The visual observations of the proppant flowback phenomena show that the sand production initiates close to the perforation. After the initiation of the sand flow, continued pumping of the water results in sand production through a channel formed in the proppant pack.
Cystathionase: immunochemical evidence for absence from human fetal liver.

Extract: Purified human liver cystathionase was obtained by ammonium sulfate fractionation (45–65% saturation), starch block electrophoresis, and disc gel electrophoresis. Antibodies to the human enzyme were induced in the rabbit using cystathionase in polyacrylamide disc gel as antigen. A pooled homogenate of liver from 14 human fetuses (5.7 to 20 cm crown-rump length), obtained at therapeutic abortion, was compared by agar double diffusion with an homogenate from normal human adult liver. A specific enzymatic stain, using cystathionine as substrate, was used to detect cystathionase activity in the immune precipitate. The extract of fetal liver did not form an enzymatically inactive immune precipitin band uniting with the catalytically active band formed between the adult liver and the antiserum. This absence was confirmed by immunotitration studies using a mixture of adult and fetal liver extracts in which the amount of fetal liver extract was equivalent to three times the total protein in the adult liver extract. The addition of fetal liver did not appreciably increase the amount of cystathionase activity remaining in the supernatant after combination with a given quantity of antibody and centrifugation to remove the enzyme-antibody complex. Speculation: Human fetal liver does not contain an enzymatically inactive precursor protein immunologically related to adult human liver cystathionase, giving evidence that the human fetus is not competent to synthesize more than trace amounts of the intact enzyme.
Numerical investigation of the anisotropic hydraulic conductivity behavior in heterogeneous porous media

The behavior of the mean equivalent hydraulic conductivity normal and parallel to stratification (K1, and K2, respectively) is studied here through Monte Carlo simulations of three-dimensional, steady-state flow in statistically anisotropic, bounded, and heterogeneous media. For water flow normal to stratification in strongly heterogeneous porous media (σ2Y=3) the value of K1 is not unique; it ranges from an arithmetic to a geometric, and finally, to a harmonic mean behavior depending on field dimensions, and medium anisotropy. For a fixed anisotropy ratio and variance of Y = ln K, the larger the distance, in the direction perpendicular to stratification, over which water flow takes place, the faster the rate at which, KH, behavior is approached. However, even for large anisotropy ratios, harmonic mean behavior appears to be a good approximation only for aquifer thickness L1 that is large enough to allow stratified flow to occur. For small aquifer thickness (L1/λ1<8, where λ1 is the integral scale normal to stratification) the limiting behavior, for large anisotropy ratios, appears to be, instead, that of two-dimensional flow, i.e., water flows primarily parallel to the planes of stratification. When the aquifer thickness is very small compared to the horizontal dimensions (and with relative similar integral scales in the three directions) a behavior resembling arithmetic mean conditions is exhibited, i.e., water flow takes place through heterogeneous, vertical, soil volumes. The geostatistical expressions of Desbarats (1992a) for upscaling hydraulic conductivity values were utilized and closed form empirical relations were developed for the main components of the upscaled hydraulic conductivity tensor.
Midtrimester premature rupture of the membranes

Midtrimester premature rupture of the membranes is an uncommon adverse complication of pregnancy with an occurrence of approximately 0.65%. Significant perinatal and maternal morbidity includes pulmonary hypoplasia, restriction deformities, and sequelae of prematurity as well as maternal chorioamnionitis and endometritis. Moreover, 31% of survivors are affected by long-term complications such as chronic lung disease, neurological and developmental abnormalities. Fetal survival is evident with increasing latency and good residual amniotic fluid (largest vertical pocket≥2 cm). In this article, we review the relevant literature regarding prognosis, counseling, and management of the patient with membrane rupture in the midtrimester.
Relative age of Camelot crater and crater clusters near the Apollo 17 landing site

Topographic profiles and depth-diameter ratios from the crater Camelot and craters of the central cluster in the Apollo 17 landing area suggest that these craters are of the same age. Therefore, layers that can be recognized in the deep-drill core and that can be identified as ejecta deposits from Camelot or from the cluster craters should yield similar emplacement ages.
The meaning of the bell inequalities

Abstract The Bell inequalities are shown to be the conditions for the probability functions of a class of systems to be expressible in a certain mathematical form.
Radiation from explosive-driven shocks in the noble gases

Abstract Shock temperatures were calculated for xenon, krypton, and argon using the strong-shock approximation and Composition B explosive as the driver. Temperatures of 38,000 31,000 and 23,000°K were obtained for Xe, Kr and A, respectively. Further calculations were made on the emergent radiation flux from the cold preshocked gas by taking into account radiation absorption in the shocked gas itself, the radiation-heated shock precursor, and the cold gas ahead of the precursor. The frequency integrated power fluxes on a target 100 cm ahead of the shock are 4·1(10)13, 3·5(10)13, and 1·4(10)13 ergs per cm2 per sec for Xe, Kr and A, respectively.
Birefringence of the mammalian midbody.

Abstract The midbody of HeLa cells was studied with polarization and electron microscopy. A band of positive birefringence was found to be associated with the midbody. The characteristic features of this pattern of birefringence indicate that it is not the result of form or intrinsic birefringence, but rather seems to be an example of edge birefringence as described by Inoue [2].
Variation Risk Management Using Modeling and Simulation

Design and manufacturing firms are under significant pressure to simultaneously increase product complexity, reduce design cycles, decrease cost, and improve quality. A key enabler to reduce cost without sacrificing quality is the control of variation during both design and manufacturing. The best time to reduce the impact of variation is in the early stages of design. This paper presents a tool set used to identify, early in the design process, where variation will have significant impact on the final cost and quality of a product. It presents the design team with a graphical view of variation risk, enabling them to quickly identify high-risk areas. The uncertainty about process capability and risk is also quantified and presented to the user.
Implementation of the conjugate gradient algorithm on a vector hypercube multiprocessor

In this paper, parallel implementation and vectorization of the Scaled Conjugate Gradient (SCG) algorithm for the solution of large sparse linear system of equations, on a vector hypercube multiprocessor (iPSC- VX), is described. Computations in the SCG algorithm consist mainly of matrix operations that can be vectorized and are implemented on the Vector Processor on each node of the hypercube. The implementation described here achieves efficient parallelization by overlapping vectorized computations with inter-node communication. A speed-up of 58 over a µVax II is obtained for large finite element meshes.
Postmyelography headache rates with Whitacre versus Quincke 22-gauge spinal needles.

PURPOSE: To compare the postdural puncture headache (PDPH) rates after myelography with use of 22-gauge Whitacre (blunt tip) versus standard 22-gauge Quincke (bevel-tip) spinal needles. MATERIALS AND METHODS: At myelography, 340 patients were randomly assigned to one of two groups in which either the Whitacre (167 patients) or the Quincke (173 patients) needle was used. Follow-up was at 48 hours and at 4 days after the procedure. Crude and adjusted Whitacre/PDPH odds ratios and risk ratios were calculated. RESULTS: The crude Whitacre needle PDPH risk was 9.6%, and the crude Quincke needle PDPH risk was 15.6%. The absolute risk difference was 6.0% with a 95% confidence interval of -0.98% and 13.04%. The adjusted Whitacre/PDPH odds ratio was 0.492 with a 95% confidence interval of 0.241 and 1.003. The Whitacre needle group had a statistically significantly lower PDPH severity grade (P = .0151), similar PDPH duration, and more technical difficulty with the needle. CONCLUSION: The Whitacre needle is associate...
On the role of γ-carboxyglutamic acid in calcium and phospholipid binding

Summary The vitamin K-dependent amino acid, γ-carboxyglutamic acid, is essential for calcium binding by prothrombin and blood clotting factor X. The studies reported here demonstrate that while γ-carboxyglutamic acid-containing peptides will bind calcium, a secondary/tertiary protein structure is also necessary to form the tight calcium binding sites which are required for binding these proteins to phospholipid surfaces.
T Helper Cell Differentiation: Regulation by cis Elements and Epigenetics

Cytokine loci undergo changes in chromatin structure when naive CD4 + T cells differentiate into Th1 or Th2 cells and have also been examined for regulatory sequences underlying such changes and their functional correlates. Studies have shown that distal regulatory elements control the Ifng and Th2 cytokine loci and are primary targets for tissue-specific transcription factors, serving as centers for epigenetic changes that mark heritable traits in effector cells. Reports of intra- and, remarkably, interchromosomal interactions between these regulatory elements shed light on the mechanisms by which they regulate gene expression, revealing an extraordinary new picture that conceptually extends our views on how genes are regulated from two to three dimensions. Here, we summarize these recent findings on the role of regulatory elements and their mechanisms of action, which are of broad significance for gene regulation, not only of the immune system but also of many, if not all, coregulated genes.
Ultrafast Gates for Single Atomic Qubits

We demonstrate single-qubit operations on a trapped atom hyperfine qubit using a single ultrafast pulse from a mode-locked laser. We shape the pulse from the laser and perform arotation of the qubit in less than 50 ps with a population transfer exceeding 99% and negligible effects from spontaneous emission or ac Stark shifts. The gate time is significantly shorter than the period of atomic motion in the trap (� Rabi=� trap > 10 4 ), demonstrating that this interaction takes place deep within the strong excitation regime.
Peripheral nerve reconnection: Immediate histologic consequences of distributed mechanical support

We tested the possibility of improving the quality of axonal repair after peripheral nerve transection by suppression of all mechanical stresses from the zone of repair. A method was developed involving mechanical support of the sciatic nerve from below in a grooved chamber with additional support provided by suturing the nerve to a rubber sleeve. Histological studies of silver-impregnated specimens from rabbit sciatic nerve using this technique revealed that the axons' tips were closely reconnected with minimal disruption in their direction or in the alignment of fibers and without extraneous material between the severed stumps. Comparison of these results with those of current microsurgical techniques showed the unequivocal superiority of this method in terms of immediate histologic aspects. The course of Wallerian degeneration was not modified.
Abstract 3918: Haploinsufficiency of MRE11A reduces DNA repair capacity in bronchial epithelial cells in response to Bleomycin and BPDE

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Reduced DNA repair capacity (DRC) and polymorphisms in genes involved in the requisite repair pathways are associated with increased risk for lung cancer and promoter hypermethylation. A SNP (rs7117042) was identified in MRE11A that resulted in a 30% reduction in gene transcription and was associated with promoter methylation in sputum from cancer-free smokers. In vitro studies have also demonstrated that formation of DNA double strand breaks (DSB) can lead to gene promoter methylation. The purpose of this study was to identify genes in the DSB repair pathway that may be rate limiting for DNA repair in response to DNA damage and ultimately assess their effect on transformation and promoter methylation. A model for haploinsufficiency was created to simulate germ line sequence variation in the MRE11A, NBS, and XRCC3 gene by shRNA stable knockdown in immortalized human bronchial epithelial cells (HBEC2 and HBEC13). The clones with 50% and 75% knockdown of target genes were selected and cell lines were exposed to increasing doses of bleomycin and BPDE respectively with DRC determined by formation of micronuclei. MRE11A knockdown reduced DRC by 2- and 2.5-fold following exposure to BPDE and bleomycin, respectively compared to parental cell lines. DRC also varied by degree of gene knock down. Studies were extended to address the functional impact of the MRE11a SNP on DRC by challenging lymphocytes wild type or heterozygote for this SNP to bleomycin. A 30-40% reduction in DRC was seen in heterozygotes compared to wild type. Studies are ongoing to address the effect of chronic carcinogen exposure of HBECs with knock down of MRE11a on transformation efficiency and induction of gene promoter hypermethylation. These studies support a important role for MRE11A in the response of the cell to double-strand break damage. Supported by NIH R01 ES015262. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3918. doi:10.1158/1538-7445.AM2011-3918
Ex-vivo gene therapy of human vascular bypass grafts with E2F decoy: the PREVENT single-centre, randomised, controlled trial.

Summary Background Cell-cycle blockade by ex-vivo gene therapy of experimental vein grafts inhibits the neointimal hyperplasia and subsequent accelerated atherosclerosis that lead to human bypass-graft failure. In a prospective, randomised, controlled trial, we investigated the safety and biological efficacy of intraoperative gene therapy in patients receiving bypass vein grafts. Methods We studied gene therapy that uses decoy oligodeoxynucleotide, which binds and inactivates the pivotal cell-cycle transcription factor E2F. 41 patients were randomly assigned untreated (16), E2F-decoy-treated (17), or scrambled-oligodeoxynucleotide-treated (eight) human infrainguinal vein grafts. Oligonucleotide was delivered to grafts intraoperatively by ex-vivo pressure-mediated transfection. The primary endpoints were safety and inhibition of target cell-cycle regulatory genes and of DNA synthesis in the grafts. Analysis was by intention to treat. Findings Mean transfection efficiency was 89·0% (SD 1·9). Proliferating-cell nuclear antigen and c-myc mRNA concentrations and bromodeoxyuridine incorporation were decreased in the EF2-decoy group by medians of 73% [IQR 53–84], 70% [50–79], and 74% [56–83], respectively) but not in the scrambled-oligodeoxynucleotide group (p Interpretation Intraoperative transfection of human bypass vein grafts with E2F-decoy oligodeoxynucleotide is safe, feasible, and can achieve sequence-specific inhibition of cell-cycle gene expression and DNA replication. Application of this genetic-engineering strategy may lower failure rates of human primary bypass vein grafting.
Student experiences with competency domains during a psychiatry clerkship.

Objectives The authors reviewed medical student encounters during 3 years of a required psychiatry clerkship that were recorded on a web-based system of six broad competency domains (similar to ACGME-recommended domains). These were used to determine diagnoses of patients seen, clinical skills practiced, and experiences in interpersonal and communications skills, professionalism, practice-based learning and improvement, and system-based practice. The authors aim to understand how students are learning and growing in these domains and to modify the clerkship in an ongoing manner.
THE EFFICACY OF GANTRISIN AS COMPARED TO KEFLEX IN THE TREATMENT OF URINARY TRACT INFECTIONS IN COLLEGE COEDS

During, the past three years on 354 occasions college coeds with culture proven acute symptomatic urinary tract infections (2 cultures >100,000 col) were treated with either Gantrisin (123) or Keflex (231) in subgroups of 3, 7, 10, 14 or 21 days. A comparison of the recurrence rates for each of the subgroups within the Gantrisin (G) and Keflex (K) groups were not statistically different. For this reason, all subgroups for each of the drugs were combined in order to compare the combined efficacy of each group. Cantrisin (Total Recurrence Rate Post Theraphy 12.79%) appears to be more effective than Keflex (Total Recurrence Rate Post Therapy 35.4%) in the treatment of urinary tract infections in college coeds. In addition, three days of therapy proved to be as effective as longer courses of therapy in these young women.
A model of perceptual classification in children and adults.

The developmental trend from overall! similarity to dimensional! identity classifications is explained by a quantitative model. I begin with the assumption that objects are represented in terms of constit! uent dimensions and that the representation of objects changes little with development. Given this assumption, the model has three major parts. First, the similarity between objects is a function of the combination of the constituent dimensional differences. 1 propose developmental change in the likelihood that dimensions are differentially weighted in the calculation of similarity. Second, the perceived similarities between objects are valued for the purpose of constructing classifications. I propose that similarities are valued more dichotomously with age, such that identity becomes in! creasingly special. Third, the valued similarities are used to choose the best classification of those possible. The model provides good qualitative fits to the extant data. Three experiments examining classifications in 2! to 8! year! olds and in adults support specific new claims of the model. The data and the model provide new insights about development, classification, and similarity. A classic controversy in the perception of multidimensional objects concerns the relation of the whole object to its constitu! ent parts. When we perceive an object, say a cup, we perceive it both as a whole and as composed of constituent attributes—as being a unitary entity that is a particular color, size, and shape. By one classic view, it is the whole as a unit that is perceptually primary and the constituent attributes are only secondarily de! rived. By an alternative view, the attributes and parts are pri! mary and the whole is built from them. Both characterizations can be argued to be right. The empirical evidence suggests that the primacy of the whole or parts depends on the particular level of processing, the particular task, and the particular stimu! lus parts (see, e.g., Kemler! Nelson, in press; Navon, 1977; Pomerantz, in press; Treisman, 1987). The primacy of wholes and parts also depends on the developmental level of the per! ceiver(see, e.g., E. J. Gibson, 1969; Werner, 1957). The tradi! tional view is that objects are perceived as undifferentiated wholes early in development and are perceived as conjunctions of attributes, features, or dimensions later in development. The implications of this developmental trend for a theory of the per! ception of objects and their constituent attributes is unclear be! cause exactly what changes with development and underlies the trend has not been specified. In this article, 1 propose a quanti!
Incorporating chemical modification constraints into a dynamic programming algorithm for prediction of RNA secondary structure

Abstract A dynamic programming algorithm for prediction of RNA secondary structure has been revised to accommodate folding constraints determined by chemical modification and to include free energy increments for coaxial stacking of helices when they are either adjacent or separated by a single mismatch. Furthermore, free energy parameters are revised to account for recent experimental results for terminal mismatches and hairpin, bulge, internal, and multibranch loops. To demonstrate the applicability of this method, in vivo modification was performed on 5S rRNA in both Escherichia coli and Candida albicans with 1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluene sulfonate, dimethyl sulfate, and kethoxal. The percentage of known base pairs in the predicted structure increased from 26.3% to 86.8% for the E. coli sequence by using modification constraints. For C. albicans, the accuracy remained 87.5% both with and without modification data. On average, for these sequences and a set of 14 sequences with known secondary structure and chemical modification data taken from the literature, accuracy improves from 67% to 76%. This enhancement primarily reflects improvement for three sequences that are predicted with <40% accuracy on the basis of energetics alone. For these sequences, inclusion of chemical modification constraints improves the average accuracy from 28% to 78%. For the 11 sequences with <6% pseudoknotted base pairs, structures predicted with constraints from chemical modification contain on average 84% of known canonical base pairs.
New vs old : descriptors can affect patients' surgical preferences

Objective The objective of the study was to determine whether the designation of a procedure as newer leads more patients to choose that procedure over 1 that is designated as older. Study Design Women with stress incontinence read two 1-page descriptions of surgical procedures for treatment of stress incontinence and were asked to indicate which of the 2 surgical procedures they would choose whether they were going to choose surgical treatment. Randomly for half the participants, a rectus fascia sling was described as being a newer procedure and a mesh sling as an older procedure. For the other half of participants, a mesh sling was described as older and a fascia sling as newer. All participants were also asked whether, in general, they considered that newer surgical procedures were better than older surgical procedures and why. Results Forty-eight women of mean age 57 years (range, 33-82) were interviewed. Thirty-two patients (68%) chose the newer procedure, and 35 (74%) chose the fascia procedure, both percentages higher than would be expected by chance. When fascia was presented as being the newer procedure, it was chosen over the older mesh by 22 of 24 patients (92%), whereas when fascia was presented as being the older procedure, it was chosen over the newer mesh by a smaller margin. The great majority of patients (79%) stated that newer procedures are better in general. Conclusions Our results suggest that the use of the words newer or older may overshadow other important information that physicians intend to convey during surgical counseling.
The Sun Dagger Interactive

The Sun Dagger Interactive is a real-time computer simulation of the ancient site on Fajada Butte in Chaco Canyon, New Mexico, and is now part of a permanent exhibit on cultural astronomy at the Adler Planetarium in Chicago. The exhibit opened on March 20, 2002.The Sun Dagger construct is dated over a thousand years old and is believed to mark both the solar year and the nineteen-year lunar cycle. This new computer application allows viewers to explore the ancient site that is no longer accessible to the public.
Genetic mechanisms underlying abnormal neuronal migration in classical lissencephaly

Classical lissencephaly is a human developmental brain disorder characterized by a paucity of cortical gyration and thickening of the cortical gray matter, leading to severe epilepsy and mental retardation. Loss-of-function mutations in the microtubule-associated protein encoding genes, PAFAH1B1 (encoding the protein LIS1), DCX and TUBA1A have been implicated in the pathogenesis of the condition. Animal models are required to understand the basis of this disease, which is a challenge, given that mice normally have a smooth cortex. Recent advances toward this goal have come from stepwise reduction in gene function, deletion of redundant genes and acute gene inactivation using short hairpin RNA (shRNA). These approaches have implicated genes that regulate the microtubule cytoskeleton during neuronal division, migration and maturation.
Resonant Rydberg-Atom-Rydberg-Atom Collisions,

We have observed the sharply resonant enhancement of the cross section of the collision process $ns+ns\ensuremath{\rightarrow}np+(n\ensuremath{-}1)p$ between two $\mathrm{Na}ns$ ($16l~nl~27$) atoms which occurs when the levels are shifted by an electric field so that the $ns$ level lies midway between the two $p$ states. The widths of the collisional resonances scale as ${n}^{\ensuremath{-}2}$ and the magnitudes of the cross sections as ${n}^{4}$, with values of 0.5 GHz and 8\ifmmode\times\else\texttimes\fi{}${10}^{8}$ ${\mathrm{\AA{}}}^{2}$ for the $20s$ state. These results are in good agreement with calculations based on the long-range dipole-dipole interaction between the two atoms.
Auger transitions initiated from singly and doubly ionized states in Li metal

Abstract Major events in Auger spectra from Li surfaces containing both Na and K have been identified. Li Auger transitions initiated from both singly and doubly ionized K shells of Li have been observed. However, no higher energy satellite corresponding to the coupling of the energy of a plasmon decay with that of the Li K VV Auger electrons was detected.
The Black Self-Concept: Some Historical and Theoretical Reflections

To understand the Negro's self-image, self-concept, and "who am I?" problems we must go back to the time of birth and creation of the "American Negro." Over 300 years ago Black men, women, and children were extracted from their native Africa, stripped bare both psychologically and physically, and placed in an alien white land.... the most tragic, yet predictable, part of all this is that the Negro has come to form his self-image and self-concept on the basis of what white racists have prescribed [Poussaint, 1970].
Cohesive energy of a van der waals crystal: inclusion of quadrupoles

Abstract A many-body theory, which takes account of quadrupolar as well as dipolar interactions, is developed for the cohesive energy of a harmonic oscillator model of a van der Waals crystal.
Magnetocardiography of Direct Currents: S-T Segment and Baseline Shifts during Experimental Myocardial Infarction

Magnetocardiograms with a bandwidth of 0 to 40 hertz were recorded from intact dogs undergoing myocardial infarction. This was done with a superconducting magnetometer in a magnetically shielded room. The purpose was to look for the steady currents of injury from the heart which supposedly produce much of the S-T segment shifts during infarction. These heart currents cannot be measured with surface electrodes because of direct-current interference from other sources, such as from the contact potential between electrode and skin. The magnetocardiograms showed both S-T segment shifts and direct currents as a result of infarction. However, they also showed that the S-T segment shifts were not produced by the direct currents. It is unlikely that these direct currents originated from the infarcted area, and their exact origin is not yet known.
Bonding of a water molecule to a copper atom

Abstract Ab initio molecular orbital calculations, including correlation effects and large basis sets, have been carried out on the interaction of a single Cu atom with a water molecule, Cu…OH 2 . The H 2 O molecule is found to be bound to Cu by 0.20 eV with nearly all of the binding coming at the correlation level. This is reduced to about 0.15 eV if correction for basis set superposition error is included. The shift in the bending frequency of water in the complex has been calculated and is in good agreement with the observed shift of this complex trapped in a low-temperature matrix. Results are also presented for the interaction of a Cu atom with two water molecules to assess the nonadditivity of the interaction.
Vascular endothelium and nitric oxide in childhood hypertension.

Vascular endothelium releases nitric oxide (NO), an important vasodilator that is continuously synthesised by the constitutive enzyme, endothelial nitric oxide synthase (NOS). This maintains a constant vasodilator tone which is diminished in adult hypertension, due to reduced endothelium-dependent vascular relaxation, which is NO dependent. In childhood, however, hypertension is often secondary, and normalisation of blood pressure by removal of cause (e.g. renal artery stenosis, catecholamine-producing tumour) suggests reversibility of endothelial dysfunction, if it is present. Raised plasma levels of endogenous inhibitors have been found, especially in children with secondary hypertension due to renal parenchymal and renovascular disease, and may contribute to hypertension by more than just inhibition of vascular NO release; e.g. by reduction of glomerular filtration rate and promotion of salt and water retention. These inhibitors also modulate renin release, which may be of relevance in cardiovascular physiology, and may also interfere with the anti-platelet properties of NO, increasing the likelihood of vascular thrombotic events. NO inhibitors also promote endothelial activation, with increased expression of adhesion molecules that may form seedlings of atherosclerosis. In chronic renal impairment, accumulation of NO inhibitors may contribute to hypertension. Efficient long-session dialysis helps better interdialysis control of blood pressure in these subjects, independent of salt and water removal, suggesting that removal of such vasoactive agents may be important for efficient blood pressure control. There are a few studies assessing NO generation in hypertensive children via plasma nitrite and nitrate, the NO end products, which suggest normal or increased production as opposed to a reduction, perhaps as a compensatory phenomenon. In the treatment of hypertension, nitroprusside and nitrates exert their actions via NO donation. Excessive production of NO (usually via inducible NOS) or excessive administration (nitrovasodilators) can be cytotoxic and may cause hypotension and shock, as in severe sepsis. NOS inhibitors and NO therefore appear to play a crucial role in aetiology, complications and therapy of childhood hypertension.
Superior structural and electronic properties for amorphous silicon–germanium alloys deposited by a low temperature hot wire chemical vapor deposition process

Abstract Very good electronic properties of hot-wire CVD a-Si,Ge:H alloys have been established by junction capacitance methods. The samples were deposited using a tantalum filament maintained at about 1800 °C instead of the usual 2000 °C tungsten filament process. Urbach energies below 45 meV were found, as well as annealed defect densities below 10 16 cm −3 , for Ge fractions up to 30 at.%. However, samples with 10 19 cm −3 levels of oxygen exhibited much broader Urbach energies and higher defect densities. Light induced degradation was examined in detail for one a-Si,Ge:H alloy sample and compared to the behavior of PECVD grown a-Si:H alloys of similar optical gap.
NEW METHODS FOR THE DESIGN OF PRODUCTS THAT SUPPORT SOCIAL ROLE TRANSITIONS

Abstract As designers transition from traditional HCI practice to experience design, they need new methods that connect experience theories to design practice. Research on product attachment – detailing why people love their stuff – indicates that attachment develops as people use products to discover who they are and desire to be. This finding hints at a design opportunity for products that support social role transition, when people must invent themselves in a new role. In advancing experience design, the authors chose to connect the theory on product attachment to design practice by developing two new design methods. They began a pilot project to design applications that could support first-year college students as they shed their high school identities to become college students. This paper documents the development of these methods, detailing the authors’ application of these in a pilot study. In addition, it shares the authors’ reflections on the effectiveness of these methods and on the larger issu...
A tale of two publics: democratizing design at the margins

The design and use of Information and Communication Technology (ICT) has now evolved beyond its workplace origins to the wider public, expanding to people who live at the margins of contemporary society. Through field work and participatory co-design with homeless shelter residents and care providers we have explored design at the common boundary of these two "publics." We describe the design of the Community Resource Messenger (CRM), an ICT that supports both those in need and those attempting to provide care in a challenging environment. The CRM consists of three components: 1) a message center that pools messages to and from mobile users into a shared, persistent forum; 2) a text and voice messaging gateway linking the mobile phones of the homeless with the web-enabled computer facilities of the care providers; 3) a shared message display accessible from mobile texting, voice, e-mail, and the web, helping the two groups communicate and coordinate for mutual good. By democratizing design and use of technology at the margins of society, we aim to engage an entire "urban network," enabling shared awareness and collective action in each public.
Accent and syllabification in Early Germanic: A response to Liberman

Anatoly Liberman's recent article in this journal (“The phonetic organization of Early Germanic” 2,1:1990) contains a number of potentially important claims about the nature of early Germanic accentuation. (1) His major conclusion appears to be twofold: first, the syllable struture of early Germanic disyllabics must have normally been CVC.V (using “.” to represent a syllable boundary), because CV (and by extension therefore CV.CV) was not a possible structure of a Gothic word. Second, early Germanic possessed no lexical stress (“word stress”), but instead only phrasal stress. (2) These conclusions are at least provocative to those familiar with the massive literature on Germanic accentology, and this was no doubt their intent. In this brief piece, I would like to note several implications and possible extensions of the points Liberman raises and the conclusions he draws, but also to disagree on some points. My perspective here differs from Liberman's primarily in focusing not on early Germanic in relation to its attested daughter languages, but rather on Germanic vis-a-vis Indo-European and some data from the languages of the world, that is, typological data.
Can we regrow a human arm? A negative perspective from an upper-limb surgeon

If we would like to devote time and money to the task of regrowing a human arm, we should feel free to do it, in principle. However, if we recognize a purpose in biomedical research, we must scrutinize this task in the light of a possible clinical application. We will then discover that regrowing a human arm is not only likely to be not possible, but also not required in the clinic. Bionic arms and better reconstructive surgery already provide a different, simpler and easier solution to the loss of a human arm, and should be promoted. Probably, “can we regrow a human arm?” is not the right question. Instead, we should ask, “can we restore the function of a lost human arm?”.
Atrial Septal Defect with Communication Through the Coronary Sinus

Abstract An unusual case is reported which illustrates a unique variation of the usually routine repair of atrial septal defects. Initial exploration of the right atrium failed to reveal a septal defect. Oxygenated blood appearing in the enlarged ostium of the coronary sinus suggested an anomaly with pulmonary venous blood entering that chamber. Identification of the communication was made by exploring the left atrium, and surgical repair could only be accomplished by the left atrial approach.
Nucleation of cosmological phase transitions

Abstract A simple model is used to describe the nucleation of bubbles during a first-order relativistic cosmological phase transition. It is shown that if the parameters governing the nucleating action vary as powers of cosmological background quantities (such as temperature), and if the action has a certain general functional form, then the characteristic size of bubbles when the transition ends is smaller than the Hubble length by a factor of at least 1/4 ln[TP/Tc], where TP is the Planck temperature and Tc is the transition temperature. It is therefore unlikely that black holes form if TP≫ Tc, or that perturbations in entropy or pressure caused by the bubbles have any significant direct effect on large-scale cosmological inhomogeneity or nucleosynthesis.
Naloxone blocks the analgesic action of levorphanol but not of dextrorphan in the leopard frog

Intraspinal injection of levorphanol (3 micrograms) at the lumbar area of the leopard frog, Rana pipiens, induced analgesia which was completely blocked by co-injection of naloxone (3 micrograms), whereas dextrorphan (3 micrograms) induced analgesia which was unaffected by naloxone. Subcutaneous levorphanol (20 or 80 mg/kg) induced a dose-dependent analgesia which was blocked by concurrent naloxone (2 mg/kg), while only the higher dose of dextrorphan (80 mg/kg) induced analgesia which was unaffected by concurrent naloxone at 8 or 80 mg/kg. These data are the first to indicate naloxone-insensitive, dextrorphan-induced analgesia.
NK cell education after allogeneic transplantation: dissociation between recovery of cytokine-producing and cytotoxic functions

Natural killer (NK) cells mediate GVL effects after allogeneic hematopoietic cell transplantation (allo-HCT) by the production of inflammatory cytokines and by direct target lysis. The acquisition of both functions was presumed to be developmentally linked, but this linkage remained unstudied after allo-HCT. We tested the cytokine production and degranulation of reconstituting NK cells after adult unrelated donor or umbilical cord blood grafting. Recipients of T cell-depleted transplants, receiving no immune suppression, showed diminished NK cell degranulation. In contrast, degranulation was normal or increased after T-cell replete transplants given with immune suppression. Strikingly, target cell-induced IFNγ production was markedly diminished in all transplant settings, especially with T cell-depleted or naive T cell-containing umbilical cord blood grafts, suggesting a role for T cells in NK education. Although degranulation was similar in the KIR(+) and KIR(-) populations that coexpressed NKG2A, target cell-induced IFNγ production was limited to the subset of NK cells expressing KIR inhibited by self-ligands. Thus, cytokine production and cytotoxic function do not consistently coexist in NK cells reconstituting after allo-HCT. Exposure to IL-15 rapidly increased target-inducible IFNγ production, indicative of IL-15's potential as a therapeutic tool to enhance NK cell function to protect against infection and relapse after allo-HCT.
Effects of indomethacin and prostaglandin injections on plasma prolactin and growth hormone levels in rats

Ovariectomized (OVX) rats were injected with estradiol benzoate (Eb, 2 μg sc) and 2 days later their plasma PRL and GH titers were determined in jugular blood samples drawn through an indwelling silastic cannula at 1- to 2-h intervals from 1000–1600 h. PRL was low in the morning and increased in the afternoon. Control OVX rats treated with oil did not show such an increase. Although Eb increased basal GH levels, plasma GH varied in a pulsatile manner in both OVX and OVX, Eb-treated rats. Indomethacin (Id), an inhibitor of prostaglandin synthesis administered 24 h before blood sampling, depressed the Ebinduced PRL release and the pulsatile GH release in a dose-related manner. Intraventricular injection of nine different prostaglandins (PGs) and two endoperoxide analogs in conscious, free-moving OVX, Eb-treated rats revealed that only PGEi released PRL and that both PGE1 and PGE2 released GH within 15 min of their injection. When [3H]PGE2 was injected intraventricularly < 3% of the injected radioactivity wa...
Taxol1 Production in Nodule Cultures of Taxus

The in vitro synthesis of secondary compounds from plants is one source of scarce and valuable phytopharmaceuticals. Often, some level of cellular or tissue differentiation is needed for the biosynthesis of many of these important compounds. Nodule cultures, consisting of cohesive multicellular units displaying a high degree of differentiation, were initiated from cultured needles of seven Taxus cultivars (Taxus cuspidata, Taxus x media 'Hicksii', Taxus x hunnewelliana 'Richard Horsey', Taxus x media 'Dark Green Spreader', Taxus x media 'L. C. Bobbick', and Taxus brevifolia). Under normal semicontinuous perfusion culture conditions (bimonthly refreshments to yield 0.2% sucrose), only trace amounts of taxol were detected from Taxus nodule cultures. However, with an elevated sucrose level (0.5% or 1.0%), taxol production was enhanced in T. cuspidata nodules to approximately 12 micrograms taxol/g nodule dry weight (dw). Stimulation of taxol production by elevated sucrose levels occurred even in the absence of other nutrients. The effect of increased sucrose on taxol induction does not appear to be due to an osmotic effect in the medium, suggesting that the increase in taxol production may be correlated with a metabolic process within the nodules. Although sucrose had a significant effect on taxol production, taxane precursors or elicitors of terpenes, as well as other plant secondary metabolites, had no effect on the production of taxol from these cultures. In addition to taxol, the higher sucrose levels also induced the production of 7-epi-10-deacetyltaxol, cephalomannine, and 7-epi-10-deacetylcephalomannine, so that total content of these taxanes equaled approximately 39 micrograms taxane/g dw nodules.
The effects of texting on driving performance in a driving simulator: the influence of driver age

Distracted driving is a significant contributor to motor vehicle accidents and fatalities, and texting is a particularly significant form of driver distraction that continues to be on the rise. The present study examined the influence of driver age (18-59 years old) and other factors on the disruptive effects of texting on simulated driving behavior. While 'driving' the simulator, subjects were engaged in a series of brief text conversations with a member of the research team. The primary dependent variable was the occurrence of Lane Excursions (defined as any time the center of the vehicle moved outside the directed driving lane, e.g., into the lane for oncoming traffic or onto the shoulder of the road), measured as (1) the percent of subjects that exhibited Lane Excursions, (2) the number of Lane Excursions occurring and (3) the percent of the texting time in Lane Excursions. Multiple Regression analyses were used to assess the influence of several factors on driving performance while texting, including text task duration, texting skill level (subject-reported), texting history (#texts/week), driver gender and driver age. Lane Excursions were not observed in the absence of texting, but 66% of subjects overall exhibited Lane Excursions while texting. Multiple Regression analysis for all subjects (N=50) revealed that text task duration was significantly correlated with the number of Lane Excursions, and texting skill level and driver age were significantly correlated with the percent of subjects exhibiting Lane Excursions. Driver gender was not significantly correlated with Lane Excursions during texting. Multiple Regression analysis of only highly skilled texters (N=27) revealed that driver age was significantly correlated with the number of Lane Excursions, the percent of subjects exhibiting Lane Excursions and the percent of texting time in Lane Excursions. In contrast, Multiple Regression analysis of those drivers who self-identified as not highly skilled texters (N=23) revealed that text task duration was significantly correlated with the number of Lane Excursions. The present studies confirm past reports that texting impairs driving simulator performance. Moreover, the present study demonstrates that for highly skilled texters, the effects of texting on driving are actually worse for older drivers. Given the increasing frequency of texting while driving within virtually all age groups, these data suggest that 'no texting while driving' education and public service messages need to be continued, and they should be expanded to target older drivers as well.
Chemostat dynamics of plasmid-bearing, plasmid-free mixed recombinant cultures

The problem of plasmid stability and strain reversion in recombinant cultures is investigated through a complete stability analysis of a plasmid-bearing, plasmid-free mixed culture growing in a chemostat. Using a general method based on the index theory of a singular point, the complete stability portrait of all competitive interactions is obtained which can occur under all possible mutual dispositions of the specific growth rate curves and chemostat dilution rate. It is found that such a mixed culture can coexist in a chemostat only if there is a range of substrate concentrations where the plasmid-bearing cells grow at a specific rate which is larger than the specific growth rate of the plasmid-free cells. Realistic further genetic modifications that could possibly yield a culture with such properties are discussed.