cssi/SciSciGPT-SciSciNet huggingface dataset:
A geometric model for the myocardium: biventricular wall stresses in normal and hypertrophied states.

Assuming truncated ellipsoidal geometry for the right and left ventricles, a model is developed for the myocardium enabling biventricular mechanical behavior to be studied. Employing pressure-volume data taken from normal dog hearts and from hearts in which the pulmonary artery has been banded over periods of 2–40 weeks, it is shown that: (a) right ventricular wall stresses are higher than left ventricular stresses; (b) right ventricular wall stress increases initially to a maximum after 3–4 weeks followed by a decline to normal and even subnormal levels, attaining a minimum value at 32–33 weeks; (c) left ventricular stresses behave in a similar manner, attaining their maximum and minimum levels after 7–8 weeks and 32–33 weeks respectively. These results suggest that surgical or medical therapy in patients with hypertrophied ventricles might be more appropriate during the period of wall stress reduction.
The effects of visual input on open-loop and closed-loop postural control mechanisms

In an earlier posturographic investigation (Collins and De Luca 1993) it was proposed that open-loop and closed-loop control mechanisms are involved in the regulation of undisturbed, upright stance. In this study, stabilogram-diffusion analysis was used to examine how visual input affects the operational characteristics of these control mechanisms. Stabilogram-diffusion analysis leads to the extraction of repeatable center-of-pressure (COP) parameters that can be directly related to the resultant steady-state behavior and functional interaction of the neuromuscular mechanisms underlying the maintenance of erect posture. Twenty-five healthy male subjects (aged 19–30 years) were included in the study. An instrumented force platform was used to measure the time-varying displacements of the COP under each subject's feet during quiet standing. The subjects were tested under eyes-open and eyes-closed conditions. The COP trajectories were analyzed as one-dimensional and two-dimensional random walks, according to stabilogram-diffusion analysis. Using this technique, it was found that visual input affects the performance of the postural control system in one of two different ways — either it significantly modifies the steady-state behavior of the open-loop postural control mechanisms, or it significantly alters the characteristics of the other closed-loop feedback mechanisms that are involved in balance control. This result is interpreted as an indication that the visual system is integrated into the postural control system in one of two different ways. The experimental population was roughly evenly divided between these two schemes. For the first group (13 of 25 subjects), visual input principally caused a decrease in the “effective” stochastic activity of the open-loop control mechanisms in both the mediolateral and anteroposterior directions. For the second group (12 of 25 subjects), visual input caused an increase in the effective stochastic activity and uncorrelated behavior of the closed-loop control mechanisms in the anteroposterior direction only. On the basis of these results, it is hypothesized that visual input, in both schemes, serves to decrease the stiffness of the musculoskeletal system. In the former case, this may be accomplished by decreasing the level of muscular activity across the joints of the lower limb, whereas, in the latter case, reduced stiffness may be achieved by reducing the gain(s) of the other postural feedback mechanisms, i.e., the proprioceptive and/or vestibular systems. Using stabilogram-diffusion analysis, it was also found that the two groups of subjects behaved similarly under eyes-closed conditions. This result suggests that the open-loop postural control mechanisms and reflex-based feedback systems, respectively, of healthy, young individuals are organized in functionally equivalent ways.
Activation of CH4 by gas-phase Ni+ and the thermochemistry of Ni-ligand complexes

The kinetic energy dependence of the reaction of Ni+ (2D) with methane has been studied using guided ion beam mass spectrometry. Formation of NiH+, NiCH2+ and NiCH3+ are all observed with thresholds near 2 eV, and NiCH+ is observed at higher kinetic energies. The dehydrogenation reaction is shown to proceed over a barrier in excess of the endothermicity by examining the reverse reaction of NiCH2(+) + D2. Collision-induced dissociation of NiCH2+ and NiCH4+ with Xe provides additional information on the products and reaction intermediates. Modeling of the endothermic reaction cross sections yields the 0 K bond dissociation energies (in eV) of D0(Ni( +)-H) = 1.60 +/- 0.08, D0(Ni(+)-CH) = 3.12 +/- 0.12, D0(Ni(+)-CH2) = 3.20 +/- 0.08, D0(Ni(+)-CH3) = 1.76 +/- 0.07, and D0(Ni(+)-CH4) = 1.00 +/- 0.05. The experimental thermochemistry is favorably compared with previous experimental results and density functional theory calculations (B3LYP), which also establish the electronic structures of these species and provide insight into the reaction mechanism. The results for Ni(+) are compared with those for the third-row transition metal congener Pt+ and the differences in behavior and mechanism are discussed.
Quantum ghost imaging

Quantum Ghost Imaging(QGI) has proven to be both a scientifically interesting field as well as one with many potential practical applications. In this paper we will review some of the scientifically fundamental aspects of Quantum Ghost Imaging and the supporting experiments including some recent results from the Army Research Laboratory.
An improved performance receiving technique for asymmetrically and symmetrically clipping optical (ASCO)-OFDM

In this paper, we propose an improved receiving technique for the asymmetrically and symmetrically clipping optical (ASCO)-OFDM intensity modulation direct detection (IM/DD) wireless communication system. In the ASCO-OFDM modulation scheme, the asymmetrically clipping optical (ACO)-OFDM symbols are modulated onto the odd subcarriers, and the symmetrically clipping optical (SCO)-OFDM symbols are modulated onto the even subcarriers. We found that the interference caused by clipping only affects the symbols on the even subcarriers. At the receiver, the ACO-OFDM symbols can be easily obtained by detecting the data on the odd subcarri-ers; the SCO-OFDM symbols can be successfully recovered by subtracting the estimated ACO-OFDM clipping noise and the SCO-OFDM clipping noise from the even subcarriers. The ACO-OFDM clipping noise is estimated from the received ACO-OFDM signals, and it can be reused to decrease the symbol error rate (SER) of ACO-OFDM signals. The SER of SCO-OFDM signals depend on the precision of ACO-OFDM signals. Thus, we apply an improved ACO-OFDM receiving technique in our current receiver to further improve the SER performance of SCO-OFDM signals as well as that of the whole system.
ATSDR's Trichloroethylene Subregistry Methods and Results: 1989-2000

The National Exposure Registry of the Agency for Toxic Substances and Disease Registry (ATSDR) uses standard methods to study human exposure in four chemical subregistries: trichloroethylene (TCE), dioxin, benzene, and trichloroethane. The TCE Subregistry includes a baseline cohort of 4006 white registrants with drinking water exposure in Michigan, Indiana, Illinois, Pennsylvania, and Arizona. Between 3 and 6 follow-ups per site were conducted from 1989 to 2000, after baseline. Standardized morbidity ratios, controlling for age and sex, compared prevalences of 16 general health conditions in the subregistry with aggregated national estimates from the 1989-1994 National Health Interview surveys. Excess cases of dermatologic, hematologic, or hepatic disorders and strokes persisted over the lifetime of the registry. Persistent excess urinary tract disorders are likely caused by a systematic bias. This review of first-generation methods may be used to strengthen future exposure registries.
Structural effects of the L145Q, V157F, and R282W cancer-associated mutations in the p53 DNA-binding core domain.

The p53 tumor suppressor is a transcription factor involved in many important signaling pathways, such as apoptosis and cell-cycle arrest. In over half of human cancers, p53 function is compromised by a mutation in its gene. Mutations in the p53 DNA-binding core domain destabilize the structure and reduce DNA-binding activity. We performed molecular dynamics simulations at physiological temperature to study the structural and dynamic effects of the L145Q, V157F, and R282W cancer-associated mutations in comparison to the wild-type protein. While there were common regions of destabilization in the mutant simulations, structural changes particular to individual mutations were also observed. Significant backbone deviations of the H2 helix and S7–S8 loop were observed in all mutant simulations; the H2 helix binds to DNA. In addition, the L145Q and V157F mutations, which are located in the β-sandwich core of the domain, disrupted the β-sheet structure and the loop-sheet-helix motif. The R282W mutation caused distortion of the loop-sheet-helix motif, but otherwise this mutant was similar to the wild-type structure. The introduction of these mutations caused rearrangement of the DNA-binding surface, consistent with their reduced DNA-binding activity. The simulations reveal detailed effects of the mutations on the stability and dynamics of p53 that may provide insight for therapeutic approaches.
The root surface phosphatases ofEriophorum vaginatum: Effects of temperature, pH, substrate concentration and inorganic phosphorus

Eriophorum vaginatum L. subsp.spissum (Fern.) Hult., a dominant plant in arctic tundra ecosystems, has acid phosphatase activity evenly distributed along its root surface from the root tip to a distance at least 16 cm from the tip. These root surface phosphatases have optimal activity from pH 3.5 to 4.0; mean soil pH for soil samples collected with roots was 3.69. Apparent energy of activation and Q10 values (14.0 kcal mol−1 and 2.2, respectively) do not provide evidence for temperature acclimation, but substantial phosphatase activity was measured at 1°C. Kinetic parameters determined for this root surface phosphatase were as follows: Km=9.23 mM, Vmax=1.61×10−3 μmoles mm−2h−1. The presence of inorganic phosphorus in the assay medium did not inhibit root surface phosphatase activity except at very high concentrations (100 mM); even then, only slight inhibition was detected (7 to 19%). A comparison of hydrolysis rates with inorganic phosphate assimilation rates measured forE. vaginatum indicates that organic phosphate hydrolysis may occur at approximately one third the rate of inorganic phosphate absorption. Calculations show that inorganic phosphate produced by root surface phosphatase activity may satisfy 65% of the annual phosphate demand ofE. vaginatum. Since arctic tundra soils are typically higher in dissolved organic phosphorus compounds than in inorganic phosphate, root surface phosphatase activity may make a considerable contribution to the phosphate nutrition of this widespread and abundant arctic plant.
Prediction of two-dimensional natural convection in enclosures with inner bodies of arbitrary shapes

The numerical prediction of laminar natural convection in two-dimensional enclosures with inner bodies of irregular but basically cylindrical shape is the subject of this paper. This problem models, for example, the fluid dynamics in a nuclear spent-fuel storage container in which the inner body represents a tight water or a fast breeder reactor fuel assembly The solution method described employs a nonorthogonal coordinate system in which the surfaces of the inner and outer boundaries coincide with coordinate surfaces. The coordinate system is generated with simple algebraic expressions. The transformed equations of motion and energy are derived on a control volume basis with central and upwind finite differences. Details of the derivation are provided. The discretiigd equations are solved within the framework of the Simplest scheme for orthogonal systems. Application of the solution methodology is illustrated with three examples.
Variation in Leaf Starch and Sink Limitations during Seed Filling in Soybean

Soybean [Glycine max (L.) Merr.] yield can be limited by the activity of the source (i.e., canopy photosynthesis) or by the ability of the seed (i.e., the sink) to utilize the assimilate produced by the source. An experiment was conducted for 3 yr at Lexington, KY, (38° N latitude) to evaluate potential source-sink limitations of early and late maturing cultivars. Two early maturing cultivars (Kasota and Hardin, Maturity Group I) and two late maturing cultivars (Essex and Hutcheson, Maturity Group V) were planted in mid-May in 0.38-m rows and the plots were irrigated to minimize water stress. Shade cloth that reduced irradiance by 63% was placed over half of the plots from approximately growth stage R6 (early seed filling) to maturity. Shade always significantly reduced the individual seed growth rate (9-32%) indicating that the plants were source limited. Leaf starch levels during seed filling were monitored to evaluate potential sink limitations. Starch levels in the late maturing cultivars usually remained constant or declined during seed filling, providing little evidence of a sink limitation. Starch levels in the early cultivars increased approximately 6-fold in the early stages of seed filling in 1 of 3 yr, suggesting that, in that year, the plants were sink limited, i.e., the seeds could not use all of the available assimilate. Source limitations during seed filling are apparently common in soybean, but sink limitations seem to occur infrequently in environments where water is not limiting.
The Effectiveness of Collaborative/Therapeutic Assessment for Psychotherapy Consultation: A Pragmatic Replicated Single-Case Study

This pragmatic study evaluated the effectiveness of a collaborative assessment intervention as an approach to midtherapy consultation, which has yet to be empirically tested. Ten adult participants in ongoing psychotherapy with a variety of presenting concerns, primarily consisting of general mood and adjustment issues, received a brief assessment-based intervention based on Finn's (2007) Therapeutic Assessment model. Following the collection of assessment questions and the administration of a multimethod assessment battery, clients and therapists participated in a joint feedback session with the assessor. Clients were then followed as their psychotherapy continued. The results of idiographic and aggregate analytic approaches revealed significant reductions in client-reported symptomatic distress, as evidenced by a medium effect size (d = -.50) and a significant change in the trajectory of distress. Client reports of the process of psychotherapy revealed a significant increase in the clients' ratings of the working alliance. The findings suggest that a midtherapy consultation using collaborative/therapeutic assessment methods is beneficial but that further rigorous investigation is needed.
Associations between intramucosal acidosis in the gut and organ failure.

OBJECTIVE To alert health professionals to the need for early detection and prevention of shock in critically ill patients. By describing the associations between intramucosal acidosis in the gut and multiple system organ failure, the author demonstrates how noninvasive measurement of gut intramucosal pH can be used to monitor the adequacy of tissue oxygenation in the splanchnic organs and predict splanchnic ischemia within minutes of its onset. DATA SOURCES Review and analysis of current medical literature on shock and organ failure, combined with the author's prior research and expertise in the areas of tissue oxygenation and tonometric monitoring in the critically ill. CONCLUSIONS The presence of defective tissue oxygenation in splanchnic organs and in gut ischemia may be detected within minutes of its occurrence via measurements of intramucosal pH in the gut. Measurement of intramucosal pH, obtained noninvasively with an intraluminally located gastrointestinal tonometer, provides an absolute metabolic measure of the adequacy of mucosal oxygenation. The putative consequences of intramucosal acidosis and associated mucosal injury include nosocomial pneumonia, myocardial depression, sepsis from enteric organisms, multiple system organ failure, and death. Through the use of routine monitoring of the adequacy of gut mucosal oxygenation, ischemic mucosal injury and its putative consequences can be prevented, resulting in reduced frequency of multiple organ failure and improved outcome.
Ethanol exposure affects trophic factor activity and responsiveness in chick embryo

Chick embryos were chronically exposed to either ethanol (approximately 30 mg/d) or saline, from E4-E13. Homogenate extract was prepared from forebrain tissue from E16 experimental and control embryos and was applied to cultured dorsal root ganglia (DRG). Neurotrophic activity in the forebrain extract (FBX) was significantly reduced in the ethanol-treated embryos compared to saline controls, both in terms of influences on neuronal survival and process elaboration. In addition, E8-9 DRGs from embryos exposed to ethanol from E4 were less viable in the presence of NGF than were those from controls. DRG survival in the presence of E16 FBX (from untreated embryos) was not different following ethanol treatment, but neurite production was significantly reduced. These results suggest that neurotrophic factor content and responsiveness may be appreciably altered following chronic prenatal ethanol exposure. Such alteration could underlie certain CNS anomalies seen in the fetal alcohol syndrome.
Photometric Properties of the Interacting Binary BO Monocerotis: Evidence for Magnetic Activity

BO Monocerotis (BO Mon) is a severely neglected short-period (2.23 days) Algol-type eclipsing binary star system undergoing angular momentum variations that are likely due to the evolved secondary star experiencing cycles of magnetic activity. We present the first CCD light curves of BO Mon, which were observed at the Kutztown University Observatory (Kutztown, PA) in 2012 using B, V, and I filters. The analysis presented here is the first of its kind for BO Mon and provides the first physical model of the system's parameters. We also incorporate over 40 yr of published times of minimum light to provide a new ephemeris curve and perform a period study that greatly improves, while differing significantly from, an earlier ephemeris analysis that was done more than 13 yr ago. The observed variations in BO Mon's orbital period supply evidence for mass transfer and magnetic activity and our photometric model affords the basic properties of the system for use in future photometric and spectroscopic studies.
A study of the expansion of the chick area vasculosa.

Abstract The radial expansion of the area vasculosa of the chick embryo was studied with regard to the location of the cells which generate the mesodermal movement. The expansion of stage 12 area vasculosae was shown to be autonomous from either continued blastoderm expansion or the continued presence of the embryo. Small glass rods were used as barriers to area vasculosa expansion. When placed peripheral to the terminal sinus, glass rods blocked the vascular expansion; however, when placed just central to the terminal sinus, glass rods had no effect on vascular expansion. In addition, removal of large amounts of tissue within the area vasculosa had no significant effect on vascular expansion. We conclude that the majority of the mesoderm within the boundaries of the terminal sinus plays no essential role in the expansion of the area vasculosa, and that the cells which generate the force for expansion are located at or very near the terminal sinus. A histological study of the area vasculosa and adjacent blastoderm was performed with light and electron microscopy. This survey showed that, as the terminal sinus and a group of mesenchymal cells just peripheral to it (“edge cells”) move out into the blastoderm, morphological changes occur in the epiblast overlying the terminal sinus and edge cells. Three major changes in the epiblast cell layer were observed: (1) The cells change from a squamous, monolayered arrangement to a cuboidal or columnar, bilayered arrangement; (2) the epiblast basal lamina is thrown into convoluted folds; (3) an electron-dense extracellular matrix becomes associated with both the epiblast basal lamina and mesenchymal edge cells. Histochemical staining (Alcian blue at pH 2.5 and 1.0 and two-step PAS) shows positive reactions at the epithelial-mesenchymal interface located just over the terminal sinus and edge cells. These results suggest that glycosaminoglycans are present in relatively large amounts at the advancing mesoderm edge.
Relationships between optical rotation and circular dichroism and elements of the Mueller matrix for natural and artificial chiral materials

Detection, identification, and characterization of natural and artificial chiral materials have found numerous applications in biochemistry, chemistry, drugs, medicine, and engineering. With the extensive use of optical polarimetric scatterometry, the relationships between the parameters related to optical activity (optical rotation and circular dichroism) and the Mueller matrix elements (which totally characterize scattered light) have been derived when the host medium for the chiral material is dissipative and nondissipative. It is shown that for the general case when optimum excitation is accounted for in the analysis, the relationship is given in terms of a complex pairing of specific quasi-off-diagonal elements of the Mueller matrix. This work provides a road map for experimentalists to determine the optimum excitation (angles of incidence and scatter), wavelength, mode of operation (reflection or transmission), and the specific Muller matrix elements that need to be measured.
Intrinsic stress effect on fracture toughness of plasma enhanced chemical vapor deposited SiNx:H films

Abstract The apparent fracture toughness for a series of plasma enhanced chemical vapor deposition SiNx:H films with intrinsic film stress ranging from 300 MPa tensile to 1 GPa compressive was measured using nanoindentation. The nanoindentation results show the measured fracture toughness for these films can vary from as high as > 8 MPa⋅√m for films in compression to as low as
Effects of soot‐induced snow albedo change on snowpack and hydrological cycle in western United States based on Weather Research and Forecasting chemistry and regional climate simulations

[1] Radiative forcing induced by soot on snow is an important anthropogenic forcing affecting the global climate. In this study we simulated the deposition of soot aerosol on snow and the resulting impact on snowpack and the hydrological cycle in the western United States. A year-long simulation was performed using the chemistry version of the Weather Research and Forecasting model (WRF-Chem) to determine the soot deposition, followed by three simulations using WRF in meteorology-only mode, with and without the soot-induced snow albedo perturbations. The chemistry simulation shows large spatial variability in soot deposition that reflects the localized emissions and the influence of the complex terrain. The soot-induced snow albedo perturbations increase the surface net solar radiation flux during late winter to early spring, increase the surface air temperature, and reduce the snow accumulation and spring snowmelt. These effects are stronger over the central Rockies and southern Alberta, where soot deposition and snowpack overlap the most. The indirect forcing of soot accelerates snowmelt and alters stream flows, including a trend toward earlier melt dates in the western United States. The soot-induced albedo reduction initiates a positive feedback process whereby dirty snow absorbs more solar radiation, heating the surface and warming the air. This warming causes reduced snow depth and fraction, which further reduces the regional surface albedo for the snow-covered regions. For a doubled snow albedo perturbation, the change to surface energy and temperature is around 50–80%; however, snowpack reduction is nonlinearly accelerated.
Reporting Femicide-Suicide in the News: The Current Utilization of Suicide Reporting Guidelines and Recommendations for the Future

Public health officials have developed and disseminated recommendations for the responsible reporting of suicide in an effort to dispel myths about suicide-completers and minimize contagion effects. However, recommendations as to the reporting of homicide-suicide events have not been a priority in these initiatives. The current study assesses the degree to which newspaper coverage of the most commonly occurring type of homicide-suicide event, femicide-suicide, adhere to existing suicide reporting recommendations by examining newspaper coverage (n = 143) of a population of femicide-suicide cases (n = 83) from North Carolina for the years 2002–2009. The current study demonstrates the importance of developing and disseminating reporting guidelines to assist in dispelling myths about the victims and perpetrators of lethal intimate partner violence.
Laparoscopic surgery in children

Summary The surgeon should be aware of the extensive applications of endoscopic surgery in the pediatric patient. The ability to provide surgical care in association with either outpatient or short-stay hospitalizations appear to be cost-effective and appropriate state-of-the-art medical care. Because the array of surgical instruments continues to evolve, new and innovative endoscopic procedures will continue to become increasingly available.
Cyano-Bridged Complexes of trans-Tetrakis(pyridine)ruthenium(II)

(3). This transformation causes a marked increase in the electronic coupling through the central Ru unit, as evidenced by a AEID value of 280 mV for the outer RulIml couples in 3. The single-crystal X-ray structures of trans-Ru(CN)2(py)4*2CH3CN and ~~~~~-[C~(~~)~RU(NC)RU(~~)~(CN)RU(~~)~C~I(PF~)~*~CH~CNC~H~N (~~CH~CNCSH~N) have been determined. The complex trans-Ru(CN)~(py)4*2CH3CN, chemical formula C26H26NgRu, crystallizes in the orthorhombic system, space group Pbcn with a = 10.4714(11) A, b = 15.0098(18) A, c = 16.1018(15) A, and Z = 4. The salt 2*5CH3CNCsHsN, chemical formula C~~H~OC~~FI~NZOP ZRU~, crystallizes in the orthorhombic system, space group Pnnm with u = 14.882(7) A, b = 23.197(6) A, c = 24.034(7) A, and Z = 4. The binding of two trans-{RuCl(py)4}+ groups has very little effect on the geometry of the trans-Ru(CN)2(py)4 unit. The complex in 2 has an almost perfectly linear geometry with eclipsed tr~ns-{Ru(py)4}~+ and bond lengths indicating dn(Ru“) - n*(CN) back-bonding from both C- and N-bonded Ru centers. The Ru-C1 bond length is 2.4212(24) A.
Master Transduction Curve for Field-Structured Chemiresistor Calibration

Chemiresistors are gas sensors for volatile organic compounds that are composed of conducting particle networks in a polymer matrix. In the presence of an analyte that is compatible with the polymer phase, the sensor conductance decreases as the analyte is absorbed, eventually reaching a steady-state value that is a measure of the analyte’s concentration. The response curve, which is the relationship between steady-state conductance and analyte activity (normalized concentration), is strongly dependent on both the chemical affinity of the analyte for the polymer and the stress field within the chemiresistor composite. Calibration of an individual sensor would seem to necessitate mapping out the response curve for each analyte of interest, a tedious and expensive proposition. In a recent paper, we have shown that the transduction curve of any particular sensor is a function of polymer swelling alone, regardless of the chemical nature of the analyte. This master transduction curve implies that sensor calibr...
New genetic links in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is increasingly diagnosed as a disorder throughout the world. It is characterized by eosinophils in the esophagus due to food allergies. Molecular analysis of esophageal biopsies and mouse models have indicated a clear role for the T helper 2 pathway, in particular interleukins 5 and 13, in this disease. Current treatment options for EoE involve avoidance of the allergens or using anti-inflammatory medications such as topical corticosteroids. In the past year, genomic research has led to the identification of single nucleotide polymorphisms in the gene encoding thymic stromal lymphopoietin (TSLP), and subsequently in the gene encoding its receptor, as disease susceptibility markers for EoE. Identification of this molecule and its receptor suggest the potential for new treatment options in the future.
Significance of minor-vein anatomy to carbohydrate transport

Plant species which translocate distinct combinations of carbohydrates in the phloem were investigated to assess whether differences in minor-vein anatomy were associated with differences in carbohydrate composition of the phloem sap. In Vicia faba L., a species in which the minor-vein companion cells are modified into transfer cells, sucrose alone was found to be the translocated form of carbohydrate. In Vicia, phloem transport of sucrose was inhibited by pretreatment of leaves with p-chloromercuribenzenesulfonic acid (PCMBS), a known inhibitor of the sucrose carrier. In contrast, in Ocimum basilicum L., a species in which the minor-vein companion cells are of the symplasmically linked intermediary cell type, both sucrose- and raffinose-family oligosaccharides were exported in the phloem. In this species, no PCMBS sensitivity was observed for phloem transport of either sucrose- or raffinose-family oligosaccharides, although a PCMBS-sensitive sucrose carrier was detected in leaf tissues. This carrier did not appear to be involved in phloem loading, rather, it appeared that phloem loading occurred via the symplasm in this species. In the polyoltranslocating species Petroselinum crispum L., the same insensitivity to PCMBS was seen, suggesting that symplasmic phloem loading also occurred. The companion cells were symplasmically connected to the surrounding bundle-sheath cells by numerous “H”-shaped plasmodesmata but were not intermediary cells, and no raffinose oligosaccharides were exported by Petroselinum. Taken together, the data indicate that apoplasmic transport may be responsible for phloem loading in species in which sucrose alone is exported. However, in those plant species in which a combination of sucrose and any other carbohydrate, including the polyols, is translocated, symplasmic phloem loading may predominate.
Nature of neonatal splenic suppressor cells in the mouse.

Abstract Due to the controversy in the recent literature concerning the T-cell nature of the neonatal mouse splenic suppressor cell, we have reexamined the nature of these cells at different stages after birth. With the use of monoclonal anti-Thy antibody we can detect T-cell products on spleen suppressor cells from BDF 1 mice at 3, 4, 5, 6, and 7 days of age. The suppressor cells are assayed by their ability to inhibit mixed-lymphocyte reactivity, which is an in vitro example of cell-mediated immunity. The neonatal spleen suppressor cells also carry products of the Ly 1 and I-J locus. Neonatal thymectomy results in a premature decrease of suppressor cell activity. These data suggest that the mouse neonatal splenic suppressor cell is a short-lived Ly 1 + , I-J + T cell.
Use of exonuclease for rapid polymerase-chain-reaction-based in vitro mutagenesis.

Abstract We describe a simple strategy for improving site-specific mutagenesis. We have combined the polymerase chain reaction (PCR) with a phage λ exonuclease (Exoλ) treatment to produce mutated fragments larger than 2.5 kb. The applicability of this approach has been proven with two overlapping mutated primers. The procedure has also been made more cost-effective by the use of a single mutated primer, which is referred to as SMP-PCR procedure. The entire procedure of kinasing the primer, amplification by PCR, Exoλ digestion and second step of PCR can be performed in less than 6 h. We have used this approach to generate a number of mutations in the Salmonella typhimurium hisP gene of the histidine transport operon.
Pharmacokinetics of acyclovir in rabbit skin after IV-bolus, ointment, and iontophoretic administrations

Abstract The aim of this study was to characterize and compare the pharmacokinetics of acyclovir (ACV) in skin and plasma after iontophoresis, IV-bolus, and ointment administrations in rabbit. On five occasions, each separated by at least 1-week washout, rabbits received a 10 mg/kg dose of ACV as IV-bolus, ACV iontophoresis for 1 h at different current densities (100, 200, 300 μA/cm 2 ) or a commercially available ointment for two hours. Blood samples were collected serially up to 6 h. Skin ACV concentrations were monitored via microdialysis using linear microdialysis probes (1 cm window). Cathodic iontophoresis was performed using commercially available patches (10 cm 2 contact area). Following IV-bolus, C max in skin occurred with a delay of 38±4 min compared with plasma. No quantifiable concentration of ACV was detected in the skin on passive drug delivery. Following iontophoresis, skin exposure to ACV was 40, 22, and 11% of that following IV-bolus. Conversely, systemic exposure to ACV was negligible and plasma concentrations were below the limit of quantification at any time-point. In skin dialysate, C max , AUC, and half-life increased with current density. During ointment application, ACV in dermis was detectable only for the first 30 min thereafter ACV skin concentrations were below the LOQ (30 ng/ml).
The search for Prester John, a projected crusade and the eroding prestige of Ethiopian kings, c.1200–c.1540

The Prester John myth of a rich and powerful Christian saviour-sovereign beyond the Muslim Middle East was enmeshed for centuries in the desire for a revival of the crusading cause. This article examines a later phase when the legend shifted to Africa, the significance of which has not been wholly appreciated, nor the ensuing contacts between continents fully elaborated. Embassies between Ethiopia and Christian potentates of the Mediterranean – in Aragon, Portugal, Italy and Burgundy – were perceived as exchanges with the Prester. Steps were taken by both sides in the hopes of building a powerful alliance against Islam. Europe gained new information on sub-Saharan Africa and found its racial paradigm challenged. Yet reality could not match all that was imaginatively imposed on Christian Ethiopia, as gradually reflected in historical narratives and literature from the late fifteenth century. The strength of the myth and its impact on global events is nonetheless extraordinary.
Regulation of prothymosin α by estrogen receptor α: molecular mechanisms and relevance in estrogen-mediated breast cell growth

Prothymosin alpha (PTalpha) is a small highly acidic protein found in the nuclei of virtually all mammalian tissues. Its high conservation in mammals and wide tissue distribution suggest an essential biological role. While the exact mechanism of action of PTalpha remains elusive, the one constant has been its relationship with the proliferative state of the cell and its requirement for cellular growth and survival. Recently PTalpha was found to promote transcriptional activity by sequestering the anticoactivator, REA from the Estrogen Receptor (ER) complex. We now report that Estradiol (E2) upregulates PTalpha mRNA and protein expression. Further studies indicate that ERalpha regulates PTalpha gene transcriptional activity. We have also delimited the region of PTalpha gene promoter involved in ERalpha-mediated transcriptional regulation and identified a novel ERalpha-binding element. Increased intracellular PTalpha expression in the presence of estrogens is accompanied by increased nuclear/decreased cytoplasmic localization. Increased nuclear expression of PTalpha is correlated with increased proliferation as measured by expression of Ki67 nuclear antigen. Conversely, inhibition of nuclear PTalpha expression in breast cancer cells using antisense methodology resulted in the inhibition of E2-induced breast cancer cell proliferation. Overall these studies underscore the importance of PTalpha in estrogen-induced breast cell proliferation.
Laser Fusion Tissue Repair With CO2 Laser

Low power CO2 laser energy is capable of remodeling collagen through a photothermal process. Methods of CO2 laser tissue fusion have been developed which permit repair of blood vessels, stomach, small bowel, fallopian tube, and vas deferens. Analyses of these reconstructions demonstrate significant injury in the area of laser impact but minimal injury of the luminal surface. Healing proceeds rapidly. The biomechanics of the laser repair are similar to that of suture repair. Preservation of the luminal surface and function, rapid healing, and the absence of foreign body suggest that CO2 laser repair may provide a better method of tissue reconstruction.© (1989) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Differential behavior of liposome-introduced specific RNAs in living Drosophila cells.

Abstract We have developed a protocol for efficiently introducing macromolecules into Drosophila tissue culture cells using liposomes. By carefully adjusting the fusion parameters, conditions have been established to routinely encapsulate 15–30% of the starting material into liposomes and to introduce 20–30% of the liposome-encapsulated material into the cells during a 30-minute fusion period. Essentially, all of the cells receive material from the liposomes and 109 cells can be fused at once. The fusion does not have any measureable effect on cell viability as assayed by trypan blue exclusion, growth rate, and cell morphology. We have utilized this technique to introduce radioactive RNAs into nonradioactive cells, thus enabling the behavior of the introduced RNAs to be followed unambiguously. Liposome-introduced small nuclear RNAs (snRNAs) are stable in the cell for at least 25 hours (approximately two cell generations), with 80% of the radioactivity remaining trichloroacetic acid (TCA) precipitable and the gel electrophoresis pattern remaining essentially unchanged. This is in contrast to liposome-introduced cytoplasmic RNAs, which are only 20% TCA precipitable after the first hour. In the cell, the introduced snRNAs attain a 10–35-fold higher concentration in the nucleus than the cytoplasm. Nuclear accumulation is not seen with Drosophila tRNA or 5s RNA, both of which attain the same nuclear as cytoplasmic RNA concentration.
Hydrocracking and hydroisomerization of high-density polyethylene and waste plastic over zeolite and silica-alumina-supported Ni and Ni-Mo sulfides

Conversion of plastic waste into transportation fuels over bifunctional catalysts was systematically studied. Previous work showed that some acid catalysts were active for degradation of pure polyolefins, but they were easily deactivated by nitrogen, sulfur, and impurities contained in actual postconsumer plastic waste. Ni and NiMo sulfides loaded on a hybrid support (HSiAl), a mixture of HZSM-5 and silica−alumina, were found to be effective for converting both pure high-density polyethylene and plastic waste to gasoline-range products. Hydrocracking reactions were carried out mostly at 375 °C, 1000 psig H2 (initial), for a reaction time of 1 h, though the effects of initial hydrogen pressure and reaction time were also examined. Ni/HSiAl had higher hydrocracking and hydroisomerization ability than did NiMo/HSiAl. The quality of liquid products obtained over Ni/HSiAl was comparable to that of a commercial premium gasoline. Moreover, being resistant to poisoning by N- and S-containing compounds, these cata...
Wide genetic variation in the native pial collateral circulation is a major determinant of variation in severity of stroke

Severity of stroke varies widely among individuals. Whether differences in the extent of the native (preexisting) pial collateral circulation exist and contribute to this variability is unknown. We addressed these questions and probed for potential genetic contributions using morphometric analysis of the collateral circulation in 15 inbred mouse strains recently shown to exhibit wide differences in infarct volume. Morphometrics were determined in the unligated left hemisphere (for native collaterals) and ligated right hemisphere (for remodeled collaterals) 6 days after permanent middle cerebral artery (MCA) occlusion. Variation among strains in native collateral number, diameter, MCA, anterior cerebral artery (ACA), and posterior cerebral artery (PCA) tree territories were, respectively: 56-fold, 3-fold, 42%, 56%, and 61%. Collateral length (P<0.001) and the number of penetrating arterioles branching from them also varied (P<0.05). Infarct volume correlated inversely with collateral number (P<0.0001), diameter (P<0.0001), and penetrating arteriole number (P<0.05) and directly with MCA territory (P<0.05). Relative collateral conductance and MCA territory, when factored together, strongly predicted infarct volume (P<0.0001). Outward remodeling of collaterals in the ligated hemisphere varied approximately 3-fold. These data show that the extent of the native pial collateral circulation and collateral remodeling after obstruction vary widely with genetic background, and suggest that this variability, due to natural polymorphisms, is a major contributor to variability in infarct volume.
The adverse effects of maternal smoking on the human placenta: A review

Studies of placental pathologies associated with maternal cigarette smoking have led to many interesting observations. For example, maternal smoking impairs human placental development by changing the balance between cytotrophoblast (CTB) proliferation and differentiation. It is likely that chronic exposure to tobacco constituents in early pregnancy can affect placental development directly or indirectly by reducing blood flow, which creates a pathologically hypoxic environment. To understand this process at a molecular level, tissue samples from non-smoking and smoking mothers were studied to determine whether active and/or passive cigarette smoke exposure affects CTB expression of molecules that govern cellular responses to oxygen tension: the von Hippel-Lindau tumor suppressor protein (pVHL), hypoxia-inducible transcription factors (HIFs) and vascular endothelial growth factor-A (VEGF). The results show that maternal smoking dysregulates CTB expression of all three types of molecules. In addition, cell columns and proliferating cells were reduced while there was a corresponding increase in cell islands. All three phenomena were most obvious in the placentas of heavy smokers. Interestingly, a subset of the aforementioned effects can be detected in samples obtained from women who were passively exposed to cigarette smoke during pregnancy. These observations suggest that tobacco constituents exert direct effects on CTB proliferation and differentiation and help to explain the mechanisms by which smoking negatively effects human pregnancy outcome.
Electrophysiological and diffusion tensor imaging evidence of delayed corollary discharges in patients with schizophrenia.

Patients with schizophrenia (SZ) characteristically exhibit supranormal levels of cortical activity to self-induced sensory stimuli, ostensibly because of abnormalities in the neural signals (corollary discharges, CDs) normatively involved in suppressing the sensory consequences of self-generated actions. The nature of these abnormalities is unknown. This study investigated whether SZ patients experience CDs that are abnormally delayed in their arrival at the sensory cortex. Twenty-one patients with SZ and 25 matched control participants underwent electroencephalography (EEG). Participants’ level of cortical suppression was calculated as the amplitude of the N1 component evoked by a button press-elicited auditory stimulus, subtracted from the N1 amplitude evoked by the same stimulus presented passively. In the three experimental conditions, the auditory stimulus was delivered 0, 50 or 100 ms subsequent to the button-press. Fifteen SZ patients and 17 healthy controls (HCs) also underwent diffusion tensor imaging (DTI), and the fractional anisotropy (FA) of participants’ arcuate fasciculus was used to predict their level of cortical suppression in the three conditions. While the SZ patients exhibited subnormal N1 suppression to undelayed, self-generated auditory stimuli, these deficits were eliminated by imposing a 50-ms, but not a 100-ms, delay between the button-press and the evoked stimulus. Furthermore, the extent to which the 50-ms delay normalized a patient’s level of N1 suppression was linearly related to the FA of their arcuate fasciculus. These data suggest that SZ patients experience temporally delayed CDs to self-generated auditory stimuli, putatively because of structural damage to the white-matter (WM) fasciculus connecting the sites of discharge initiation and destination.
Anode Materials for High-Average-Power Operation in Vacuum at Gigawatt Instantaneous Power Levels

The thermal behavior of several electrically conducting solids under high incident electron fluence in high vacuum was evaluated. At electron energies of up to $\sim 200$ keV, the depth-dose relationship for electron penetration into the materials was considered, and the resulting energy deposition profile from the surface was revealed to extend to a maximum of $\sim 175\mu \text{m}$ below the surface depending on the anode material. Black body radiation is considered as the major mechanism that balances the power deposited in the material on the timescales of interest. Comparing the radiated power density at the sublimation temperature for different materials, metallic/nonmetallic, revealed that pyrolytic graphite anodes may radiate over 20 times more power than metallic anodes before failure due to sublimation. In addition, transparent pyrolytic graphite anodes (with a thickness on the order of several tens of micrometer) potentially radiate up to 40 times that of metallic anodes, since heating by the electron beam is approximately uniform throughout the thickness of the material, thus radiation is emitted from both sides. Experimental results obtained from titanium and pyrolytic graphite anodes validate the thermal analysis.
Covalent Sidewall Functionalization of Single Wall Carbon Nanotubes

Alkyllithium reagents may be used to attach alkyl groups to the sidewalls of fluoro nanotubes. Thermal gravimetric analysis combined with UV-vis-Nir spectroscopy has been used to provide a quantitative measure of the degree of functionalization. SWNTs prepared using the HiPco process exhibit a higher degree of alkylation than SWNTs from the laser-oven method, indicating that the smaller diameter fluoro tubes are alkylated more readily. The spectral signature of the pristine SWNTs can be regenerated when the alkylated SWNTs are heated in Ar at 500 °C, demonstrating that dealkylation occurs at this temperature. TGA-MS analysis using a sample of n-butylated h-SWNTs showed that 1-butene and n-butane are formed during thermolysis.