Molecular self-assembly at bare semiconductor surfaces: cooperative substrate-molecule effects in octadecanethiolate monolayer assemblies on GaAs(111), (110), and (100)

The structures of self-assembled monolayers formed by chemisorption of octadecanethiol onto the surfaces of GaAs(001), (110), (111-A)-Ga, and (111-B)-As have been characterized in detail by a combination of X-ray photoelectron, near-edge X-ray absorption fine structure, and infrared spectroscopies and grazing incidence X-ray diffraction. In all cases, the molecular lattices are ordered with hexagonal symmetry, even for the square and rectangular intrinsic substrate (001) and (110) lattices, and the adsorbate lattice spacings are all incommensurate with their respective intrinsic substrate lattices. These results definitively show that the monolayer organization is driven by intermolecular packing forces to assemble in a hexagonal motif, such as would occur in the approach to a limit for an energetically featureless surface. The accompanying introduction of strain into the soft substrate surface lattice via strong S substrate bonds forces the soft substrate lattice to compliantly respond, introducing quasi-2D strain. A notably poorer organization for the (111-A)-Ga case compared to the (111-B)-As and other faces indicates that that the Ga-terminated surface lattice is more resistant to adsorbate packing-induced stress. Overall, the results show that surface molecular self-assembly must be considered as a strongly cooperative process between the substrate surface and the adsorbate and that inorganic substrate surfaces should not be considered as necessarily rigid when strong intermolecular adsorbate packing forces are operative.

Anti-sports anaemia effects of verbascoside and martynoside in mice

This paper aims to investigate the effects of verbascoside and martynoside isolated from PEDICULARIS DOLICHOCYMBA on sports anaemia. Forty mice were divided into four groups: Group R (control group, nonsupplemented and maintained at rest), Group E (nonsupplemented and undergoing exercise), Group VE (supplemented with verbascoside 10 mg/kg per day and undergoing exercise), and Group ME (supplemented with martynoside 10 mg/kg per day and undergoing exercise). After 5 weeks intensive swimming exercises, we measured the RBC count, the hemoglobin concentration, the hematocrit (Hct), the mean corpuscular hemoglobin concentration (MCHC) and the mean corpuscular hemoglobin (MCH). We studied the shapes of RBC and measured the plasma malonyldialdehyde (MDA). We found Group E showed lower RBC, hemoglobin and Hct levels, higher MCHC, MCH, plasma MDA levels and the abnormally shaped RBCs percentage than Groups R, VE and ME. Group ME showed lower RBC and Hct levels, higher MCH, plasma MDA levels and the abnormally shaped RBCs percentage than Group VE. The results indicated that verbascoside and martynoside have the potential of antagonizing sports anaemia, the mechanism of this effect might be related to preventing RBC from free radical damage. Moreover, verbascoside was found to be more active than martynoside.

Growth, microstructure, and infrared-ultraviolet optical conductivity of La(0.5)Sr(0.5)CoO(3) nanocrystalline films on silicon substrates by pulsed laser deposition

La(0.5)Sr(0.5)CoO(3) (LSCO) nanocrystalline (nc) films have been directly grown on silicon wafers under different substrate temperatures by pulsed laser deposition. The X-ray diffraction analysis indicate that the films are polycrystalline with the pure perovskite phase at higher substrate temperatures. The columnar growth formation with the nanocrystalline structure in the films has been confirmed by microscopy experiments. Infrared-ultraviolet optical properties of the LSCO films have been investigated with the aid of spectroscopic ellipsometry (SE). Dielectric function in the photon energy range of 1.1-3.1 eV (400-1100 nm) has been extracted by reproducing the experimental data with a Lorentz oscillator model. It is found that the real part is decreased from 4.7 to -0.7 at the near-infrared region with increasing substrate temperature. The optical conductivity shows a different variation trend for the lower and higher growth temperatures, respectively. Note that the films deposited above 650 degrees C exhibit the well-defined metallic phase behavior. The discrepancies could be mainly ascribed to different crystalline structure and surface morphology. The present results may be crucial for future applications of ferromagnetic-based optoelectronic and spin-electronic devices.

In vitro characterization and pharmacokinetics of dapagliflozin (BMS-512148), a potent sodium-glucose cotransporter type II inhibitor, in animals and humans

(2S,3R,4R,5S,6R)-2-(3-(4-Ethoxybenzyl)-4-chlorophenyl)-6-hydroxymethyl-tetrahydro-2H-pyran-3,4,5-triol (dapagliflozin; BMS-512148) is a potent sodium-glucose cotransporter type II inhibitor in animals and humans and is currently under development for the treatment of type 2 diabetes. The preclinical characterization of dapagliflozin, to allow compound selection and prediction of pharmacological and dispositional behavior in the clinic, involved Caco-2 cell permeability studies, cytochrome P450 (P450) inhibition and induction studies, P450 reaction phenotyping, metabolite identification in hepatocytes, and pharmacokinetics in rats, dogs, and monkeys. Dapagliflozin was found to have good permeability across Caco-2 cell membranes. It was found to be a substrate for P-glycoprotein (P-gp) but not a significant P-gp inhibitor. Dapagliflozin was not found to be an inhibitor or an inducer of human P450 enzymes. The in vitro metabolic profiles of dapagliflozin after incubation with hepatocytes from mice, rats, dogs, monkeys, and humans were qualitatively similar. Rat hepatocyte incubations showed the highest turnover, and dapagliflozin was most stable in human hepatocytes. Prominent in vitro metabolic pathways observed were glucuronidation, hydroxylation, and O-deethylation. Pharmacokinetic parameters for dapagliflozin in preclinical species revealed a compound with adequate oral exposure, clearance, and elimination half-life, consistent with the potential for single daily dosing in humans. The pharmacokinetics in humans after a single dose of 50 mg of [(14)C]dapagliflozin showed good exposure, low clearance, adequate half-life, and no metabolites with significant pharmacological activity or toxicological concern.

<i>Tropomodulin 1 (TMOD1)</i> is associated with lean meat growth and meat quality in the pig (Brief Report)

Abstract. Tropomodulin 1 (TMOD1) is a member of the tropomodulin family, which are highly conserved capping proteins of the pointed ends of the erythrocyte membrane and sarcomeric actin filaments. Tropomodulins are involved in the architecture of the sarcomere in muscle cells and the membrane skeleton in nonmuscle cells (COLUCCIO et al. 1994, GREGORIO et al. 1995). TMOD1 is predominantly expressed in vertebrate cardiac muscle and slow twitch muscle fibers, and it binds to one end of tropomyosin (TM) that plays important roles in regulating the function of actin filament (FISCHER et al. 2003, GUNNING et al. 2008). Here we identified a single nucleotide polymorphism (SNP) in the porcine TMOD1 gene and further analyzed the effects of this gene on the lean meat growth, meat quality and other related traits in pigs.

Fetal programming of skeletal muscle development in ruminant animals

Enhancing skeletal muscle growth is crucial for animal agriculture because skeletal muscle provides meat for human consumption. An increasing body of evidence shows that the level of maternal nutrition alters fetal skeletal muscle development, with long-term effects on offspring growth and performance. Fetal skeletal muscle development mainly involves myogenesis (i.e., muscle cell development), but also involves adipogenesis (i.e., adipocyte development) and fibrogenesis (i.e., fibroblast development). These tissues in fetal muscle are mainly derived from mesenchymal stem cells (MSC). Shifting the commitment of MSC from myogenesis to adipogenesis increases intramuscular fat (i.e., marbling), improving the quality grade of meats. Strong experimental evidence indicates that Wingless and Int (Wnt)/beta-catenin signaling regulates MSC differentiation. Upregulation of Wnt/beta-catenin promotes myogenesis, and downregulation enhances adipogenesis. A lack of nutrients in early to midgestation reduces the formation of secondary muscle fibers in ruminant animals. Nutrient deficiency during mid- to late gestation decreases the number of intramuscular adipocytes and muscle fiber sizes. Knowledge of this regulatory mechanism will allow the development of strategies to enhance muscle growth and marbling in offspring, especially in the setting of nutrient deficiency.

Urban and rural variation in walking patterns and pedestrian crashes

OBJECTIVE

To examine the urban and rural variation in walking patterns and pedestrian crashes.

DESIGN

The rates of pedestrians being struck by motor vehicles was estimated according to miles walked and resident years.

SETTING

New York State, USA during 2001 through 2002.

PARTICIPANTS

35 732 pedestrians struck by vehicles.

MAIN OUTCOME MEASURES

The adjusted rate ratio (aRR) of pedestrian-vehicle crash and pedestrian injury based on resident years and miles walked according to urban and rural areas.

RESULTS

Compared with rural areas, the aRR for a pedestrian-vehicle collision, based on resident years, was 2.0 (95% CI 1.7 to 2.3) in small urban areas, 1.8 (95% CI 1.5 to 2.3) in mid-size urban areas, and 4.2 (95% CI 3.6 to 4.8) in the large urban area. The aRR based on miles walked was 2.3 (95% CI 1.6 to 3.2) in small urban areas, 2.0 (95% CI 1.4 to 2.9) in mid-size urban areas, and 1.9 (95% CI 1.4 to 2.7) in the large area. The aRR for a fatal pedestrian injury, based on miles walked, was 2.1 (95% CI 1.3 to 3.6) in small urban areas, 1.9 (95% CI 1.3 to 2.9) in mid-size urban areas, and 0.9 (95% CI 0.6 to 1.3) in the large urban area.

CONCLUSIONS

The rate of pedestrian crashes and injuries in small and mid-size urban areas was twice that in rural areas, whether based on resident years or miles walked. The high rate of pedestrian crashes in the large urban area based on resident years could be partly explained by the fact that residents in such areas walk about twice as much as residents in rural areas. The rate of fatal pedestrian injury based on miles walked was similar in the large urban area and rural areas.

Vasorelaxing action of vasonatrin peptide is associated with activation of large-conductance Ca(2+)-activated potassium channels in vascular smooth muscle cells

The aim of this study was to test the hypothesis that vasorelaxing action of vasonatrin peptide (VNP) is due to activation of the large-conductance Ca(2+)-activated potassium channel (BK(Ca)) via guanylyl cyclase (GC)-coupled natriuretic peptide receptors (NPRs) in vascular smooth muscle cells (VSMCs). Contraction experiments were performed using human radial artery, whereas BK(Ca) current by patch clamp was recorded in cells from rat mesenteric artery. Contractility of rings cut from human radial artery was detected in vitro. As a result, VNP induced a dose-dependent vasorelaxation of human radial artery, which could be mimicked by 8-Br-cGMP, and suppressed by TEA, a blocker of BK(Ca), HS-142-1, a blocker of GC-coupled NPRs, or methylene blue (MB), a selective inhibitor of guanylyl cyclase. Sequentially, whole-cell K(+) currents were recorded using patch clamp techniques. BK(Ca) current of VSMCs isolated from rat mesentery artery was obtained by subtracting the whole cell currents after applications of 10(-7) mol/l iberiotoxin (IBX) from before its applications. In accordance with the results of arterial tension detection, BK(Ca) current was significantly magnified by VNP, which could also be mimicked by 8-Br-cGMP, whereas suppressed by HS-142-1, or MB. Taken together, VNP acts as a potent vasodilator, and NPRA/B-cGMP-BK(Ca) is one possible signaling system involved in VNP induced relaxation.

Sensorized waste collection container for content estimation and collection optimization

The concurrent effects of a fast national growth rate, of a large and dense residential area and a pressing demand for urban environmental protection create a challenging framework for waste management in Pudong New Area, Shanghai. The complexity of context and procedures is indeed a primary concern of local municipal authorities due to problems related to the collection, transportation and processing of residential solid waste. In order to design and implement a suitable urban solid waste system, the first task is to forecast the quantity and variance of solid waste as it relates to residential population, consumer index, season, etc. The system here discussed addresses exactly these issues, by means of an intelligent, sensorized container. The container has been prepared and tested in the Pudong New Area, Shanghai.

Improved calibration technique for in vivo proton MRS thermometry for brain temperature measurement

The most common MR-based approach to noninvasively measure brain temperature relies on the linear relationship between the (1)H MR resonance frequency of tissue water and the tissue's temperature. Herein we provide the most accurate in vivo assessment existing thus far of such a relationship. It was derived by acquiring in vivo MR spectra from a rat brain using a high field (11.74 Tesla [T]) MRI scanner and a single-voxel MR spectroscopy technique based on a LASER pulse sequence. Data were analyzed using three different methods to estimate the (1)H resonance frequencies of water and the metabolites NAA, Cho, and Cr, which are used as temperature-independent internal (frequency) references. Standard modeling of frequency-domain data as composed of resonances characterized by Lorentzian line shapes gave the tightest resonance-frequency versus temperature correlation. An analysis of the uncertainty in temperature estimation has shown that the major limiting factor is an error in estimating the metabolite frequency. For example, for a metabolite resonance linewidth of 8 Hz, signal sampling rate of 2 Hz and SNR of 5, an accuracy of approximately 0.5 degrees C can be achieved at a magnetic field of 3T. For comparison, in the current study conducted at 11.74T, the temperature estimation error was approximately 0.1 degrees C.

Thyrotoxicosis and acute abdomen--still as defying and misunderstood today? Brief observations over the recent decade

BACKGROUND

Clinicians managing thyrotoxic patients with acute abdomen face challenging diagnostic and risky therapeutic dilemmas.

AIM

To analyse the frequency of medical vs. surgical acute abdomen, and to characterize the poorly understood thyrotoxic medical acute abdomen phenomenon.

DESIGN

Retrospective review of case notes.

METHODS

All case files with a simultaneous diagnosis of thyrotoxicosis and acute abdomen admitted between 1994 and 2004 were traced and audited.

RESULTS

Thirteen had a history of thyrotoxicosis while 12 were newly diagnosed. The commonest cause was Graves' disease. Twenty-three (92%) cases were thyrotoxic, of whom six (24%) had thyroid crisis, while two (8%) had subclinical thyrotoxicosis. The provisional diagnosis of acute abdomen was correct in 14 cases (56%), but discordant with the final diagnosis in 11 cases (44%). Eight cases (32%) without any demonstrable pathology were medical, vs. four (16%) with surgical acute abdomen, while 11(44%) had gastritis, hepatobiliary-pancreatic disorders or diverticulitis conservatively managed. The epigastrium and/or central abdomen (72.7%) were the commonest affected regions in medical acute abdomen.

CONCLUSION

Although the majority of acute abdomen in thyrotoxicosis was medical in nature, our experience indicates that surgical conditions were not uncommon. Thus, serious causes requiring life-saving surgery should be excluded before attributing it to medical acute abdomen.

Patterns of expression and function of the p75(NGFR) protein in pancreatic cancer cells and tumours

BACKGROUNDS/AIMS

Pancreatic carcinoma is one of the most aggressive human malignancies. The aggressive and highly metastatic behaviour of pancreatic carcinoma may partly be attributable to the autocrine and/or paracrine interactions involving altered expression of neurotrophin growth factors and their corresponding receptors. The aim of the present study is to investigate the expression pattern and function of the p75(NGFR) protein in pancreatic cancer cell lines and tumours to explain the phenomenon of perineural invasion in pancreatic cancer.

METHODS

The expression of p75(NGFR) in 137 pancreatic adenocarcinoma samples and the corresponding adjacent pancreatic samples was examined immunohistochemically using the EnVision Plus System. Then we examined the in vitro chemotaxis behaviour of cancer cells transfected with p75(NGFR) plasmid to nerve growth factor (NGF).

RESULTS

Immunostaining for p75(NGFR) was weak or absent in both normal pancreata and pancreatic carcinoma tissues; however, the immunostaining was relatively weaker in the pancreatic carcinoma tissues than in the normal pancreata. It is interesting to note that p75(NGFR) expression in the cancer tissues was positively correlated with the degree of perineural invasion (chi(2)=32.94, P<0.01). The chemotaxis ability of the p75(NGFR)-transfected pancreatic cancer cells to NGF was significantly stronger than that of the non-transfected or vacant vector transfected cells (P<0.01).

CONCLUSIONS

Our findings indicate that p75(NGFR) expression may be involved in the perineural invasion of pancreatic cancer cells, and the mechanism might be through mediating the chemoattraction of cancer cells for neural tissues.

Heterogeneity of kinase inhibitor resistance mechanisms in GIST

Most GIST patients develop clinical resistance to KIT/PDGFRA tyrosine kinase inhibitors (TKI). However, it is unclear whether clinical resistance results from single or multiple molecular mechanisms in each patient. KIT and PDGFRA mutations were evaluated in 53 GIST metastases obtained from 14 patients who underwent surgical debulking after progression on imatinib or sunitinib. To interrogate possible resistance mechanisms across a broad biological spectrum of GISTs, inter- and intra-lesional heterogeneity of molecular drug-resistance mechanisms were evaluated in the following: conventional KIT (CD117)-positive GISTs with KIT mutations in exon 9, 11 or 13; KIT-negative GISTs; GISTs with unusual morphology; and KIT/PDGFRA wild-type GISTs. Genomic KIT and PDGFRA mutations were characterized systematically, using complementary techniques including D-HPLC for KIT exons 9, 11-18 and PDGFRA exons 12, 14, 18, and mutation-specific PCR (V654A, D820G, N822K, Y823D). Primary KIT oncogenic mutations were found in 11/14 patients (79%). Of these, 9/11 (83%), had secondary drug-resistant KIT mutations, including six (67%) with two to five different secondary mutations in separate metastases, and three (34%) with two secondary KIT mutations in the same metastasis. The secondary mutations clustered in the KIT ATP binding pocket and kinase catalytic regions. FISH analyses revealed KIT amplicons in 2/10 metastases lacking secondary KIT mutations. This study demonstrates extensive intra- and inter-lesional heterogeneity of resistance mutations and gene amplification in patients with clinically progressing GIST. KIT kinase resistance mutations were not found in KIT/PDGFRA wild-type GISTs or in KIT-mutant GISTs showing unusual morphology and/or loss of KIT expression by IHC, indicating that resistance mechanisms are fundamentally different in these tumours. Our observations underscore the heterogeneity of clinical TKI resistance, and highlight the therapeutic challenges involved in salvaging patients after clinical progression on TKI monotherapies.