cssi/SciSciGPT-SciSciNet huggingface dataset:
Enhanced CO monolayer electro-oxidation reaction on sulfide-adsorbed Pt nanoparticles: A combined electrochemical and in situ ATR-SEIRAS spectroscopic study

Abstract The influence of adsorbed sulfide (S2−ads) on CO monolayer electro-oxidation reaction (CMOR with M for monolayer to emphasize that oxidation always starts with a saturated CO coverage) on carbon-supported Pt nanoparticles (Pt/C NPs) was investigated using electrochemical and in situ ATR-SEIRAS (attenuated total reflection-surface enhanced IR absorption spectroscopy) techniques. An enhanced kinetics of CMOR on the S2−ads-Pt/C was observed by potentiodynamic CO stripping and potentiostatic CO oxidation analyses. Electrochemical impedance measurements revealed a weakened bonding of oxygen-containing species with the S2−ads-Pt/C surface as compared with the clean Pt/C surface, which we believe was the main reason for the observed enhanced CMOR by the S2−ads. The in situ SEIRAS data showed the existence of both linear- and bridge-bonded CO (COL and COB respectively) in all samples and that the sulfide adsorption increased substantially the fraction of the former on the available Pt sites and facilitated the conversion between them. Our results also indicate that the frequently observed pre-CMOR current arises most likely from oxidation of weakly-bonded CO rather than from reactions taking place at defect sites.
THE OVARIAN HISTOLOGY OF THE DIAMOND-BACKED WATER SNAKE, NATRIX RHOMBIFERA DURING THE REPRODUCTIVE CYCLE.

The changes in the gross morphology of the ovarian follicles, atretic follicles, and corpora lutea during the reproductive cycle of Natrix rhombifera are similar to those occurring in other viviparous colubrids of temperate latitudes. Evidence is presented for a type of bursting atresia. The production of mature ova probably requires 2.5 years; consequently, female Natrix require at least 2.5 years to become sexually mature. Follicular growth is slow over the first two years, but most of the growth occurs prior to ovulation during the spring of the third year. In Missouri, ovulation probably occurs between 15 May and 15 June; gestation is approximately three months in duration.
Is there any indication for aortic valvuloplasty in the elderly

Elderly patients with severe symptomatic calcific aortic stenosis do poorly with medical management. The optimal treatment for this group of patients is surgical valve replacement. Balloon valvuloplasty may be useful as a bridge to aortic valve replacement in hemodynamically unstable patients, in patients undergoing emergent noncardiac surgery, and in patients with severe comorbidities who are too ill to undergo cardiac surgery. Balloon valvuloplasty often results in symptomatic improvement; however, the postvalvuloplasty valve area is usually <1.0 cm2, the major periprocedural complication rate is roughly 5%, and the 6-month restenosis rate is quite high. There is no evidence that balloon valvuloplasty alters the natural history of aortic stenosis, although no randomized study has been performed.
The Accretion Disk and White Dwarf during the Quiescence of the Dwarf Novae VW Vulpeculae and χ Leonis

We have carried out an International Ultraviolet Explorer archival comparative study of the two U Geminorum type dwarf novae VW Vulpeculae and x Leonis. The spectrum of x Leo does not show any C iv, a feature normally seen in the vast majority of other dwarf novae. For VW Vul, a single-temperature high- gravity photosphere does not produce a consistent fit. The best-fit accretion disk model corresponds to , , and yr 1 . For x Leo, we find that a white dwarf model with 9 ˙ M p 0.55 Mi p 41 M p 10 M wd ,, K gives the best fit to the far-UV spectrum. However, a model accretion disk with parameters T p 33,000 eff , , and yr 1 also gives a satisfactory fit to the far-UV continuum. However, 10 ˙ M p 0.80 Mi p 60 M p 10 M ,, the accretion rate derived for VW Vul is within a factor of 3 of the critical value, while the accretion rate of x Leo is within a factor of 60 of the critical rate. If we have identified the accreting white dwarf in x Leo, then it strengthens the overall conclusion that the white dwarfs in cataclysmic variables above the period gap appear to be a factor of 1.5-2 times hotter than the accreting white dwarfs in dwarf novae below the period gap.
Growth and Applications of Single-Nanowire GaN Light-Emitting Diodes

We discuss two applications of single-nanowire GaN light-emitting diodes: optical interconnects and multifunction scanning probes. These applications take advantage of the native morphology of nanowires and the high mechanical strength of GaN.
Globally optimal joint uplink base station association and power control for max-min fairness

In a heterogeneous network (HetNet) with a large number of low power base stations (BSs), proper user-BS association and power control is crucial to achieving desirable system performance. In this paper, we consider the joint BS association and power allocation problem for an uplink cellular network under the max-min fairness criterion. We first present a binary search method whereby a QoS (Quality of Service) constrained subproblem is solved at each step. Then, we propose a normalized fixed point iterative algorithm to directly solve the original problem and prove its geometric convergence to the global optimal solution, which implies the pseudo-polynomial time solvability of the considered problem. Simulation results show that the proposed normalized fixed point iterative algorithm converges much faster than the binary search method.
Permanent Magnet System for 35 GHz Second Harmonic Gyroklystron

Abstract A permanent magnet system for 35GHz gyroklystron operating at second harmonic was designed and manufactured by using Optimization Algorithm and the Finite Elements Method. The axial magnet field strength of plat region is about 0.7 T, and satisfies certain configure accurately even at the cathode region.
Investigation of Cellular Interactions of Nanoparticles by Helium Ion Microscopy

The helium ion microscope (HIM) probes light elements (e.g. C, N, O, P) with high contrast due to the large variation in secondary electron yield, which minimizes the necessity of specimen staining. A defining characteristic of HIM is its remarkable capability to neutralize charge by the implementation of an electron flood gun, which eliminates the need for coating non-conductive specimens for imaging at high resolution. In addition, the small convergence angle in HeIM offers a large depth of field (~5× FE-SEM), enabling tall structures to be viewed in focus within a single image. Taking advantage of these capabilities, we investigate the interactions of engineered nanoparticles (NPs) at the surface of alveolar type II epithelial cells grown at the airliquid interface (ALI). The increasing use of nanomaterials in a wide range of commercial applications has the potential to increase human exposure to these materials, but the impact of such exposure on human health is still unclear. One of the main routs of exposure is the respiratory tract, where alveolar epithelial cells present a vulnerable target at the interface with ambient air. Since the cellular interactions of NPs govern the cellular response and ultimately determine the impact on human health, our studies will help delineating relationships between particle properties and cellular interactions and response to better evaluate NP toxicity or biocompatibility. The Rutherford backscattered ion (RBI) is a helium ions imaging mode, which backscatters helium ions from every element except hydrogen, with a backscatter yield that depends on the atomic number of the target. Energy-sensitive backscatter analysis is being developed, which when combined with RBI image information, supports elemental identification at helium ion nanometer resolution. This capability will enable distinguishing NPs from cell surface structures with nanometer resolution.
Nitrogen-14 and the Shell Model

A shell-model calculation was done of the lower lying levels of N/sup 14/ under the assumption that the C/sup 12/ nucleus forms an inert core about which two nucleons can move in lp/sub 1/2/, 2s/sub 1/2/, 1d/sub 5/2/, or 1d/sub 3/2/ orbitals. It was possib le to give shell-model assignments to practically all of the observed levels in N/sup 14/ below 10.50 Mev, and these assignments are in good agreement with the experimental data and with other theoretical calculatioin. Several levels not predicted by this model are expected to arise from the excitation of lp/sub 8/2/ particle(s) out of the C/sup 12/ core into higher orbitals. (auth)
Multispectral and Hyperspectral Imaging: introduction to the feature issue

This Applied Optics feature issue on multispectral and hyperspectral imaging focuses on the leading research across various disciplines in this field of research.
On Utilizing Directional Antenna in 802.11 Networks: Deafness Study

This paper presents a performance study of the deafness effect caused by the use of directional antenna in 802.11 networks. We show that different assumptions on antenna and channel model lead to different conclusions on the impact of deafness on network performance. Specifically, it is shown that in the presence of channel scatters between the transmitter and the receiver, directional antenna does not pose significant deafness and performance degradation. We also show that there always exists a CCA (clear-channel-assessment) threshold that eliminates deafness completely, even under existing 802.11 MAC protocols.
N-Benzylgalactonoamidines as potent β-galactosidase inhibitors

Abstract A series of N-benzylgalactonoamidines was synthesized to probe their inhibitory ability during the hydrolysis of o-nitrophenyl-β- d -galactopyranoside by β-galactosidase (Aspergillus oryzae). All compounds are characterized as potent competitive inhibitors with inhibition constants (Ki) in the low nanomolar range (12–48 nM). The structure of the inhibitors mimics the bond-lengthening during the hydrolysis and the aromatic aglycon of the substrate. The electronic nature of the substituent in p-position of the aglycon influences the overall inhibitory ability most when compared to the unsubstituted parent compound.
Characterization of silver catalysts for the oxidation of methanol

Abstract The selection of a silver catalyst system for further study was determined on a basis of cost and its ability to oxidize formaldehyde selectively. In addition a silver catalyst can provide a low light off temperature for the conversion of methanol to carbon dioxide and water vapor. Silver catalysts were prepared by the deposition of solutions of silver nitrate or silver chloride on gamma alumina washcoat supported on cordierite monolith. These silver catalysts were characterized by a variety of analytical techniques including TEM, SEM, EMP, STEM, XRF, XRD and FTIR. It is concluded that the best silver catalyst is prepared by deposition of silver from a solution of silver ammnonium chloride onto a cordierite supported high surface area gamma alumina washcoat, drying at 100°C in air, followed by reduction in flowing 3% H2 in N2 at 500°C for 4 h. This procedure will produce a silver catalyst with highest activity, largest retention and most uniform distribution of silver. The procedure also retains the concentration of silver and the gamma phase of alumina at temperatures as high as 1000°C in air for as long as 6 h. Due to the inability of normal TEM imaqing modes to obtain silver particle size information in the presence of the small gamma alumina washcoat particles a model system was made to test the ability of a dedicated STEM to furnish that information. The model system consisted of silver particles in the range of 1 to 50 nm which had been evaporated onto a uniform thin film of alumina. High resolution X-ray maps obtained from the model system demonstrate the ability to determine location and size of silver particles > 5 nm. A number of catalysts containing noble and base metals supported on gamma alumina washcoat on a cordierite monolith have also been studied. Laboratory flow reactor studies and chassis dynamometer studies using a Mercury Lynx modified to burn neat methanol have shown the following order of activity for conversion of methanol burned in experimental or engine exhaust gas: Pd > Ag > Pt + Rh > CuO + ZnO + Cr2O3 > Ni.
Synergistic enhansons located within an acute phase responsive enhancer modulate glucocorticoid induction of angiotensinogen gene transcription

The hepatic transcription of the angiotensinogen gene is regulated by both glucocorticoids and cytokines generated as products of the acute phase reaction. We have identified a multimodular enhancer in the 5′-flanking region of the rat angiotensinogen gene that mediates these responses and consists of an acute phase response element (APRE) flanked on both sides by adjacent glucocorticoid response element consensus motifs (GREs). Induction of transcription by the cytokine interleukin-1 (IL-1) is glucocorticoid dependent and mediated through the APRE. The APRE binds in a mutually exclusive manner a cytokine/phorbol ester-inducible protein (BPi), indistinguishable from nuclear factor kB, and a family of constitutive liver proteins (BPcs) related to the heat-stable transcription factor C/EBP. Using mutated 5′-flanking sequences of the angiotensinogen gene fused to a firefly luciferase reporter gene transfected into hepatoblastoma (HepG2) cells, we have mapped enhanson sequences required for the transcriptiona...
Hypoxia and hypoxia-inducible factors as regulators of T cell development, differentiation, and function

Oxygen is a molecule that is central to cellular respiration and viability, yet there are multiple physiologic and pathological contexts in which cells experience conditions of insufficient oxygen availability, a state known as hypoxia. Given the metabolic challenges of a low oxygen environment, hypoxia elicits a range of adaptive responses at the cellular, tissue, and systemic level to promote continued survival and function. Within this context, T lymphocytes are a highly migratory cell type of the adaptive immune system that frequently encounters a wide range of oxygen tensions in both health and disease. It is now clear that oxygen availability regulates T cell differentiation and function, a response orchestrated in large part by the hypoxia-inducible factor transcription factors. Here, we discuss the physiologic scope of hypoxia and hypoxic signaling, the contribution of these pathways in regulating T cell biology, and current gaps in our understanding. Finally, we discuss how emerging therapies that modulate the hypoxic response may offer new modalities to alter T cell function and the outcome of acute and chronic pathologies.
On the product of twists of rank two and a conjecture of Larsen

In this note we present examples of elliptic curves and infinite parametric families of pairs of integers (d,d′) such that, if we assume the parity conjecture, we can show that E d ,E d′ and E dd′ are all of positive even rank over ℚ. As an application, we show examples where a conjecture of M. Larsen holds.
Negotiating improved interconnection between US telcos and their competitors

Abstract The issue of determining the types and quality of interconnection between US telephone companies and their new competitors is addressed. Instead of prescribing a detailed solution, a regulatory commission should establish ground rules for negotiations, ie ‘market rules’. It must also establish the ‘starting point’ from which bargaining can take place. A ‘starting point’ for negotiations is the a priori property rights vested in the bargaining parties.
P-93: Characterizing Dielectric Tensors with Biaxial Ellipsometry

Dielectric tensors of anisotropic substrates and films can be determined by biaxial ellipsometry, an extension of conventional ellipsometry. This technique utilizes an angle-of-incidence Mueller matrix imaging polarimeter. An example of the determination of the dielectric tensor of liquid crystal polymer films for retarders is presented.
Iron(III)-Salophene: An Organometallic Compound with Selective Cytotoxic and Anti-Proliferative Properties in Platinum-Resistant Ovarian Cancer Cells

Background In this pioneer study to the biological activity of organometallic compound Iron(III)-salophene (Fe-SP) the specific effects of Fe-SP on viability, morphology, proliferation, and cell-cycle progression on platinum-resistant ovarian cancer cell lines were investigated.
Regional and racial differences in the prevalence of physician‐diagnosed essential tremor in the United States

For reasons that are unclear, prevalence estimates of essential tremor (ET) differ considerably across the United States. Separate communities have never been sampled within the framework of the same study to substantiate these differences. We estimated the prevalence of physician-diagnosed ET in the elderly in four communities in the United States in whom the same screening questions were used, and examined whether this prevalence differed between Caucasians and African Americans. The Cardiovascular Health Study recruited a sample of Medicare beneficiaries ≥65 years of age from four communities in different regions of the United States. In 1998 to 1999, 3,494 participants (mean age, 80.0 years; range, 70–103 years) answered a 12-question screen for ET, including the question, “has a doctor diagnosed you as having familial tremor or benign essential tremor?” Fifty-four participants reported that a doctor had diagnosed them as having ET (1.5%; 95% confidence interval, [CI], 1.1–2.0%). Prevalence was similar across the four communities (1.1–2.0%). A larger proportion of Caucasians than African Americans reported a diagnosis of ET (1.7% vs. 0.4%; odds ratio = 4.9; 95% CI, 1.2–20.2; P = 0.028). In a logistic regression analysis, physician-diagnosed ET was associated with Caucasian ethnicity (P = 0.038) but not with age, gender, education, mental status or depression scores, income, smoking status, or alcohol consumption. When a standardized screening question was used, the proportion of participants with physician-diagnosed ET was similar across four communities, suggesting that the prevalence of this condition may be less variable than is often reported. Caucasians were five times more likely to have physician-diagnosed ET than were African Americans. This study does not provide an explanation for this difference, which deserves further study. © 2003 Movement Disorder Society
Interaction of Salinity and Temperature on the Germination of Crambe

(...) A laboratory experiment was designed to determine salinity tolerance of crambe during germination and salinity × temperature interactions that may influence germination and stand establishment. Treatment solutions were prepared using NaCl and CaCl 2 in 2:1 molar ratio. Salinity (electrical conductivities of 0.03, 6.3, 12.1, 17.3, 22.5, 27.1, 32.0 and 36.3 dS m −1 ) and temperature (5, 10, 15, 20, 25 and 30 °C) effects on germination of Meyer' crambe seed were determined over a 12 d period. Counts were taken at 3 d intervals and germination percentages and rate indexes were determined (...)
Conversion from liquid to solid rapamycin formulations in stable renal allograft transplant recipients

Sirolimus (rapamycin, RAPA, Rapamune™) is a potent immunosuppressive agent currently being investigated for prophylaxis against acute rejection episodes in renal transplant recipients. In the present study, stable renal allograft recipients under maintenance therapy with RAPA and cyclosporine (CsA) were converted from the original oil-based liquid RAPA to a solid tablet formulation on a milligram-to-milligram basis, in order to evaluate the pharmacokinetics and safety of this new dosage form. Twelve-hour pharmacokinetic (PK) profiles of both RAPA and CsA were conducted with the final liquid RAPA dose, and at 2, 4, and 8 weeks postconversion to the solid tablet. In addition, the parameters of the PK profiles for the solid formulation were compared with those for liquid RAPA, which were performed prior to this study. Area under the concentration–time curve (AUC) values for the liquid formulation and for the solid tablet at 2, 4, and 8 weeks postconversion were 256.5, 205.8, 226.1, and 224.4 ng·h/mL, respectively (p=NS). Time to maximum RAPA concentration was longer at 4 weeks postconversion, but similar at 2 and 8 weeks. There were no differences observed between the liquid and solid tablet trough concentrations. The only significant differences observed among the PK parameters of the solid tablet versus those of the liquid formulation were the lower Cmax values of the solid, namely 25.3, 24.9, and 26.7 ng/mL versus 37.1 ng/mL (p<0.05). In addition, the dose corrected Cmax was lower in the solid tablet PK profiles compared with the prior PK profiles for the liquid (7.7 versus 10.2 ng/mL, p<0.02). Cyclosporine AUC values did not change appreciably during the study. Conversion from the liquid to the solid formulation was neither associated with episodes of acute rejection, nor changes in laboratory values, during the 8-week study. In summary, conversion from the liquid to the solid RAPA formulation resulted in similar PK profiles and appears to be both safe and well-tolerated in renal transplant recipients. Copyright © 1999 John Wiley & Sons, Ltd.
Gender, Entitlement, and the Distribution of Family Labor

Research is reviewed demonstrating that although wives contribute a disproportionate share of the unpaid labor of the family (e.g., housework and childcare) compared to their husbands, they nonetheless report relative contentment with this unequal distribution. It is argued that wives' paradoxical contentment can be understood by considering men's and women's sense of personal entitlement with regard to what they should put into and receive from marriage in the domain of family work. Gender differences in entitlement are hypothesized to result from societal norms regarding women's and men's roles within the family, comparison processes, and justifications that legitimize an unequal division of family labor.
Novel targeted agents for platelet-derived growth factor receptor and c-KIT in malignant gliomas

Malignant gliomas are a heterogeneous group of tumors with a varying natural history and response to treatment. Despite current therapeutic strategies, these tumors almost universally recur after excision and are associated with a poor survival. Increasingly, the true heterogeneity of these tumors is being correlated with distinct molecular subgroups. Platelet-derived growth factor receptor (PDGFR) alpha is almost universally expressed on glioma cells; expression of the proto-oncogene c-KIT has also been reported. These findings have led to the clinical investigation of inhibitors of this pathway, such as imatinib and dasatinib, for the treatment of recurrent malignant glioma. To date, this approach in unselected patients has been disappointing. However, isolated responses have been seen, which may correlate with constitutive activation of one or more of the corresponding tyrosine kinases. In the future, it is hoped that an increasing knowledge of glioma biology will translate into the more judicious use of these and other targeted therapies, resulting in improvements in patient outcomes. This review describes the preclinical science behind PDGFR and c-KIT, the clinical importance of these molecular pathways and the available data from translational clinical trials.
Reaction of hydrogen with the high temperature (C14) form of TiCr2

Abstract At −78 °C the high temperature (C14) form of the intermetallic compound TiCr 2 will react directly and reversibly with hydrogen to form two non-stoichiometric hydride phases having the nominal compositions of TiCr 1.9 H 2.5 and TiCr 1.9 H 3.5 . The lower hydride phase is more stable than the higher. Standard free energies of formation of these phases at −78 °C are − 1.29 ± 0.04 and + 2.76 ± 0.02 kJ (g atom H 2 2 ) −1 with corresponding plateau pressures of approximately 0.2 and 30 atm. Relative partial molal thermodynamic quantities are also given for several other hydrogen compositions. At room temperature pressure-composition isotherms and X-ray diffraction data indicate the absence of any hydride phases: the starting (C14) intermetallic simply undergoes a lattice expansion with increasing hydrogen content without phase or structural changes. The critical temperature for the first miscibility gap region is approximately +15−20 ° C . Hysteresis is also absent in this intermetallic-hydrogen system.
Macrocycle contraction reactions of 5,35 : 14,19-diimino-7,12 : 21,26 : 28,33-trinitrilopentabenzo [c,h,m,r,w][1,6,11,16,21]pentaazacyclopentacosinato-dioxouranium(VI)

Displacement of the uranyl ion from 5,35 : 14,19-diimino-7,12,21,26 : 28,33-trinitrilopentabenzo [c,h,m,r,w][1,6,11,16,21]pentaazacyclopentacosinatodioxouranium(VI) with a variety of metal ions is accompanied by ring contraction, yielding the corresponding metal phthalocyanine.
Decay of globin mRNA during megakaryocytic differentiation of erythroleukemic cell line is accomplished through shortening of the poly(A) tail and degradation from the 3' end of the transcript

Abstract Human erythroleukemic cell line K562 normally co-expresses erythroid and megakaryocytic genes, but treatment with an activator of the protein kinase C (PKC), tumor-promoting phorbol ester 12-myristate 13-acetate (PMA) shifts these cells toward megakaryocytic pathway of differentiation. This shift results in silencing of erythroid genes and in additional activation of megakaryocytic genes. It was shown that destabilization of the most abundant erythroid mRNA of K562 cells coding for fetal globin (γ-globin,) is partially responsible for its silencing in phorbol ester-induced K562 cells. In this work the mechanism of the γ-globin mRNA destabilization is further investigated. The results show that this process is accompanied by the progressive shortening of the γ-globin mRNA poly(A) tail. Also, degradation intermediates of γ-globin mRNA observed during the course of PMA treatment are shown to contain an intact 5′ end, but lack the sequences at the 3′ end. Based on these findings, a model for the selective destabilization of the erythroid mRNAs during the course of megakaryocytic differentiation of K562 cells is proposed.
The conservation of biological diversity and U.S. agriculture: Goals, institutions, and policies

Abstract This article attempts to provide a preliminary assessment of how agricultural and related policy research has generally neglected biological conservation, the significance of the policy changes now underway, and the need for further policy changes. Policy changes are identified which could promote increased cooperation between agricultural and conservation biology researchers and practitioners. The policy and policy research implications of seriously pursuing a new and challenging goal for agriculture are explored. A review and examination of past U.S. agricultural goals, institutions, and policies suggests that the legacy of agriculture's gradual transformation over the past two centuries, and particularly the past several decades, has led to an increasing genetic impoverishment of farm habitats and rural landscapes. New national goals concerning genetic diversity of farm habitats and rural landscapes are defined as ecological goals and point to developing and adaptive and resilient food and agricultural system as part of the larger need to develop a more adaptive and resilient society. Agricultural goals, and the institutionalization that has led to the attainment of goals for great crop productivity and high labor efficiency of industrial agriculture, have been achieved through very high energy inputs. Such agriculture is based on the availability of fossil fuel and is vulnerable to climate changes. Examples of ways to modify policy to enhance diversity include making changes in current set-aside policies, credit programs, and rangeland management. In developing policies, current paradigms should be reexamined and issues of water and energy should receive highest priority. The aesthetic value and diversity of rural landscapes should also be considered. Strategies need to be developed for setting changes in agricultural policies that will lead to more diversified, lower-input agricultural systems.
Defining Care in the Culture of the Chronically Mentally Ill Living in the Community

The ethnonursing method was used to discover care meanings, expressions, and experiences of the chronically mentally ill to guide nurses in promoting the health and well-being of these people. Fifteen key and 24 general informants were interviewed. Six major themes were abstracted: (a) care as listening and giving presence is meaningful to the chronically mentally ill; (b) they desire to give care to others; (c) they are a subculture; (d) mental illness carries a public stigma in the dominant culture; (e) flexible and growth-promoting care practices are desired; and (f) the chronically mentally ill desire normalcy but fear rejection by the dominant culture.
The abundance of tritons and deuterons in primary cosmic radiation

An attempt has been made to determine the abundance of low-energy tritons and deuterons in a nuclear emulsion stack exposed at a geomagnetic latitude, λ =61° N on August 3, 1958 under 3.8 g/cm2 of matter. The grain density versus range method has been used for identification of the tracks produced by the singly charged nuclei. The selection criteria allow the observation of deuterons of kinetic energy (92÷175) MeV per nucleon and tritons of (73÷165) MeV per nucleon. The upper limits for the differential fluxes for tritons and deuterons are 3.5·10-3 and 9.2·10-3 peters per MeV for the energy ranges given above. The upper limit for the triton to α-particle ratio for the same rigidity (1.14 to 1.48 G-V) is 0.09. Some of the implications of these results are discussed. However, due to the uncertainty of the correction for secondary production within the atmosphere, the results are consistent with the absence of these elements in primary cosmic radiation
Impact of symmetry on the ferroelectric properties of CaTiO3 thin films

Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO3, through the careful control of the biaxial strain state and TiO6 octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO3 films grown on La0.18Sr0.82Al0.59Ta0.41O3 (LSAT) and NdGaO3 (NGO) substrates experienced a 1.1% biaxial strain state but differed in their octahedral tilt structures. A suppression of the out-of-plane rotations of the TiO6 octahedral in films grown on LSAT substrates resulted in a robust ferroelectric I4 mm phase with remnant polarization ∼5 μC/cm2 at 10 K and Tc near 140 K. In contrast, films grown on NGO substrates with significant octahedral tilting showed reduced polarization and Tc. These results highlight ...
Thermally Activated Friction

The temperature dependence of the kinetic friction between a highly oriented pyrolytic graphite surface and a silicon nitride probe tip has been evaluated through atomic force microscopy measurements performed under an ultra-high vacuum environment over the temperature range 140–750 K. As temperature increases from 140 to 400 K a sharp decrease in friction is observed. A relatively weaker dependence on temperature is observed in the friction measured between 400 and 750 K. Collectively, these results obtained from a fundamental interface are consistent with an activated mechanism of energy dissipation during sliding.
Correlation between sonochemistry of surfactant solutions and human leukemia cell killing by ultrasound and porphyrins.

Abstract The synergistic effect of ultrasound and drugs on cells is known as sonodynamic therapy. The use of sonodynamic therapy for the potential clinical treatment of certain tumors is promising, however, the mechanism of sonodynamic therapy could be due to either sonomechanical and/or sonochemical effects on the cells. The aim of the current study is to determine the importance of the sonochemical mechanism for sonodynamic therapy. Sonochemical effects arise from the formation of radical species following collapse of cavitation bubbles. The synergistic effect of ultrasound (47 kHz) and analogues of a gallium-porphyrin derivative (ATX-70) on cytolysis of Human leukemia cells (HL-525 and HL-60) suspended in a cell culture medium were studied. Organic surfactants preferentially accumulate and subsequently decompose at the gas/solution interface of cavitation bubbles, producing secondary radicals that can diffuse to the bulk solution. The gallium porphyrin analogues used in the current study possess two n-alkyl side chains (ATX-C x , where x = number of carbon atoms, ranging from x = 2 to x = 12). By varying the n-alkyl chain length, thereby modifying the surfactant properties of the ATX-C x derivatives, cell killing in relation to the accumulation of ATX-C x derivatives at the gas/solution interface of cavitation bubbles was determined. Following sonolysis in the presence of ATX-C x , a strong correlation for the yield of carbon-centered radicals and cell killing was observed. These results support the hypothesis that a sonochemical mechanism is responsible for the synergistic effect of ultrasound and ATX-C x on HL-525 and HL-60 cells.
Hemorrhagic Skin Reactions in Rabbits with Cutaneous Sensitization to Streptococci and Pneumococci (Shwartzman Phenomenon).

SummaryWhen an intracutaneous injection of bacterial filtrates or heat-killed organisms into sensitized rabbits was followed by intravenous injections of sufficient amounts of killed or living organisms, a hemorrhagic reaction frequently developed at the site of the intracutaneous injection.The most intense hemorrhagic reactions were observed in animals with the highest degree of cutaneous sensitization. We did not observe hemorrhagic phenomena in non-sensitized animals treated in a similar manner.
Kinetics of phosphorylation of Na+/K(+)-ATPase by protein kinase C.

Abstract The kinetics of phosphorylation of an integral membrane enzyme, Na + K + - ATPase , by calcium- and phospholipid-dependent protein kinase C (PKC) were characterized in vitro. The phosphorylation by PKC occurred on the catalytic α-subunit of Na + K + - ATPase in preparations of purified enzyme from dog kidney and duck salt-gland and in preparations of duck salt-gland microsomes. The phosphorylation required calcium (Ka ≈ 1.0 μM) and was stimulated by tumor-promoting phorbol ester (12-O-tetradecanoylphorbol 13-acetate) in the presence of a low concentration of calcium (0.1 μM). PKC phosphorylation of Na + K + - ATPase was rapid and plateaued within 30 min. The apparent Km of PKC for Na + K + - ATPase as a substrate was 0.5 μM for dog kidney enzyme and 0.3 μM for duck salt-gland enzyme. Apparent substrate inhibition of PKC activity was observed at concentrations of purified salt-gland Na + K + - ATPase greater than 1.0 μM. Phosphorylation of purified kidney and salt-gland Na + K + - ATPase occurred at both serine and threonine residues. The 32P-phosphopeptide pattern on 15% sodium dodecyl sulfate-polyacrylamide gel electrophoresis after hydroxylamine cleavage of pure 32P-phosphorylated α subunit was the same for the two sources of enzyme, which suggests that the phosphorylation sites are similar. The results indicate that Na + K + - ATPase may serve as a substrate for PKC phosphorylation in intact cells and that the Na + K + - ATPase could be a useful in vitro model substrate for PKC interaction with integral membrane proteins.
The Excitation of Surface Waves by a Vertical Antenna

The excitation of surface waves by a vertical, linear antenna erected on an infinite, flat, perfectly conducting image plane coated with a thin layer of dielectric is investigated theoretically. Helmholtz-type integral expressions, derived through the use of the results of a previous paper, are utilized in the computation of numerical data. The appendix is devoted to the development of an approximate current distribution for the antenna. The far-zone fields for the configuration are composed of two types of waves-the radiated wave, a wave of spherical type, and one or more surface waves, waves of cylindrical TM type which attenuate exponentially with height above the dielectric surface. The theoretical magnitudes of these two are combined to yield field patterns that show the large magnitude of the surface-wave component excited by the vertical antenna. The experimental approximation to the configuration consisted of a large ground plane enclosed by a microwave dark room. The experimental data, in addition to being presented so as to verify the theory, were replotted in a form that yields convenient design curves for surface wave antennas of this type. Additional measurements were taken over partially coated surfaces to aid in both the understanding of the phenomenon and its practical application to directive radiators.
Physician Knowledge and Attitudes of Minnesota Laws Concerning Adolescent Health Care

Abstract Study Objective: To determine physicians' knowledge and attitudes of medico-legal issues affecting adolescent health care. Design, Setting, Participants: A cross-sectional, mailed survey was distributed to 900 randomly selected primary care physicians in Minnesota, and all eligible physicians in Olmsted County. Interventions: Physicians were mailed a survey with questions concerning Minnesota consent and confidentiality laws. Main Outcome Measures: Physician knowledge and attitudes of consent and confidentiality laws. Results: A total of 317 (26%) surveys were returned. Olmsted county physicians achieved a median score of 37.5% and non-Olmsted physicians achieved a median score of 50% correct on a test of knowledge. Using a scoring scale where −1 signified "a bad law," 0 signified "neither a good nor bad law," and +1 signified "a good law," attitude regarding the laws was a median of +0.5 for both groups. In all, 41.1% of Olmsted physicians and 51.7% of non-Olmsted physicians felt that the laws had affected them or their practice. Olmsted physicians were compared to a cohort of Olmsted parents previously reported, with statistically significant differences noted. Conclusions: Results suggest that primary care physicians are not knowledgeable of Minnesota laws affecting adolescent health care. Opinion of these laws was positive, with notable exceptions. Physicians lack a sense of impact of laws affecting adolescent health care. Physicians were more knowledgeable and felt more positively about the laws than did parents of adolescents. Lack of knowledge and the presence of certain attitudes identify areas where physicians could benefit from greater understanding.
Measurement of regional cerebral glucose uptake by magnetic resonance spin-lock imaging

Abstract Purpose The regional uptake of glucose in rat brain in vivo was measured at high resolution using spin-lock magnetic resonance imaging after infusion of the glucose analogue 2-deoxy- d -glucose (2DG). Previous studies of glucose metabolism have used 13 C-labeled 2DG and NMR spectroscopy, 18 F-labeled fluorodeoxyglucose (FDG) and PET, or chemical exchange saturation transfer (CEST) MRI, all of which have practical limitations. Our goal was to explore the ability of spin-lock sequences to detect specific chemically-exchanging species in vivo and to compare the effects of 2DG in brain tissue on CEST images. Methods Numerical simulations of R 1p and CEST contrasts for a variety of sample parameters were performed to evaluate the potential specificity of each method for detecting the exchange contributions of 2DG. Experimental measurements were made in tissue phantoms and in rat brain in vivo which demonstrated the ability of spin-lock sequences for detecting 2DG. Results R 1p contrast acquired with appropriate spin-lock sequences can isolate the contribution of exchanging protons in 2DG in vivo and appears to have better sensitivity and more specificity to 2DG–water exchange effects than CEST. Conclusion Spin-lock imaging provides a novel approach to the detection and measurement of glucose uptake in brain in vivo .
Frontier: a graphical interface for portfolio optimization in a piecewise linear-quadratic risk framework

“Frontier” is a pilot graphical user interface for portfolio optimization built for the new IBM workstation, the RISC System/6000™, out of basic X-windows and OSL utilities. The program asks the user to select a piecewise linear-quadratic risk measure, draws a risk/reward efficient frontier, and permits the user to examine the efficient frontier using zoom and histogram display facilities. This paper describes the interfaces and discusses possible extensions.
Spectrum of calcific aortic valve disease: pathogenesis, disease progression, and treatment strategies.

Received October 26, 2004; revision received January 13, 2005; accepted February 4, 2005. Calcific aortic valve disease is a slowly progressive disorder with a disease continuum that ranges from mild valve thickening without obstruction of blood flow, termed aortic sclerosis, to severe calcification with impaired leaflet motion, or aortic stenosis (Figure 1). In the past, this process was thought to be “degenerative” because of time-dependent wear-and-tear of the leaflets with passive calcium deposition. Now, there is compelling histopathologic and clinical data suggesting that calcific valve disease is an active disease process akin to atherosclerosis with lipoprotein deposition, chronic inflammation, and active leaflet calcification. The overlap in the clinical factors associated with calcific valve disease and atherosclerosis and the correlation between the severity of coronary artery and aortic valve calcification provide further support for a shared disease process. Figure 1. Gross specimen of minimally diseased aortic valve (left) and severely stenotic aortic valve (right). In the severely stenotic valve, there are prominent lipocalcific changes on aortic side of valve cusps (arrow), with sparing of commissures. ### Anatomy of Normal Aortic Valve The normal aortic valve comprises 3 layers. The ventricularis, on the ventricular side of the leaflet, is composed of elastin-rich fibers that are aligned in a radial direction, perpendicular to the leaflet margin. The fibrosa, on the aortic side of the leaflet, comprises primarily fibroblasts and collagen fibers arranged circumferentially, parallel to the leaflet margin. The spongiosa is a layer of loose connective tissue at the base of the leaflet, between the fibrosa and ventricularis, composed of fibroblasts, mesenchymal cells, and a mucopolysaccharide-rich matrix. These layers work in concert to provide tensile strength and pliability for decades of repetitive motion. ### Early Lesion of Aortic Sclerosis Histopathologic studies of aortic sclerosis show focal subendothelial plaquelike lesions on the aortic side of the leaflet that extend to the adjacent fibrosa layer. Similarities to …
Coming of age with the internet A qualitative exploration of how the internet has become an integral part of young people’s lives

Analyzing autobiographical essays written by 72 young adult college students, this study investigates how coming of age concurrently with the internet and related technologies has influenced these young people’s lives. An understanding of how the technology is influencing the various domains of their lives provides a window on what internet use may be like for future generations. Essays revealed insights into four primary domains: self, family, real communities, and virtual communities. Within each of these domains, participants’ responses tended to focus on key dualities. Additionally, these young people report a growing dependency on the internet for activities ranging from managing their daily lives to building and maintaining virtual communities.
Determination of Preferential Interaction Parameters by Multicomponent Diffusion. Applications to Poly(ethylene glycol)−Salt−Water Ternary Mixtures

Poly(ethylene glycol) (PEG) is a hydrophilic nonionic polymer used in many biochemical and pharmaceutical applications. We report the four diffusion coefficients for the PEG-KCl-water ternary system at 25 degrees C using precision Rayleigh interferometry. Here, the molecular weight of PEG is 20 kg mol(-1), which is comparable to that of proteins. The four diffusion coefficients are examined and used to determine thermodynamic preferential interaction coefficients. We find that the PEG preferential hydration in the presence of KCl is 1 order of magnitude larger than that previously obtained under the same conditions for lysozyme, a protein of similar molecular weight. In correspondence, the coupled diffusion in the PEG case was greater than that observed in the lysozyme case. We attribute this difference to the greater exposure of polymer coils to the surrounding fluid compared to that of globular compact proteins. Moreover, we observe that the PEG preferential hydration significantly decreases as salt concentration increases and attribute this behavior to the polymer collapse. Finally, we have also employed the equilibrium isopiestic method to validate the accuracy of the preferential interaction coefficients extracted from the diffusion coefficients. This experimental comparison represents an important contribution to the relation between diffusion and equilibrium thermodynamics.
Metamodeling of Wi-Fi Performance

The increasing popularity of Wireless Fidelity (Wi-Fi) networks at home, in public areas and in the enterprise motivates extensive modeling and analysis of their performance measures, such as network capacity, resource requirements and quality of service (QoS) capabilities. Some of the easier performance problems can be solved by analytical modeling methods, but most of the complicated ones, involving too many factors from multiple layers, can only be answered through validated simulation models. However, an explicit mathematic model is always the most effective way to represent the system behavior and the most convenient basis for performance optimization. Here, we first advocate the application of metamodeling techniques to performance studies of Wi-Fi networks, in order to find usable, if approximate, closed-form mathematical models. Subsequently, we formulate a general metamodeling framework for Wi-Fi networks. Our results in two relevant case studies, after applying this framework, support the validity of our metamodeling methodology: our capacity metamodel for 802.11 Distributed Coordination Function (DCF) is validated by a well-known analytical model and displays an interesting log-linear relationship between capacity and number of users; our voice over Wi-Fi admission capacity metamodel gives a much tighter bound than bounds existing in the literature and composes a more practical admission control scheme. Our work, therefore, points out a new direction for future performance studies of Wi-Fi networks.