julilili42/papers huggingface dataset:
Surface Organobarium and Organomagnesium Chemistry on Periodic Mesoporous Silica MCM‐41: Convergent and Sequential Approaches Traced by Molecular Models
2011-09-05

Abstract The alkaline earth metal alkyl complexes [Ba(AlEt 4 ) 2 ] n and Mg(AlMe 4 ) 2 were directly grafted onto periodic mesoporous silica MCM‐41, which had been dehydroxylated at 270 °C (specific surface area a s : 1023 m 2 g −1 ; pore volume V p : 1.08 cm 3 g −1 ; main pore diameter 3.4 nm). Alternatively, barium alkyl surface species were generated by sequential grafting of MCM‐41 with Ba[N(SiHMe 2 ) 2 ] 2 (thf) 4 and AlEt 3 to yield the hybrid material AlEt 3 @Ba[N(SiHMe 2 ) 2 ] 2 (thf) 4 @MCM‐41. For a better understanding of the surface chemistry, AlEt 3 @MCM‐41 was also accessed. All hybrid materials were analyzed by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, elemental analysis, nitrogen physisorption, and solid‐state NMR spectroscopy; this clearly revealed distinct surface chemistry for the alkylaluminate‐treated materials [Ba(AlEt 4 ) 2 ]@MCM‐41 and Mg(AlMe 4 ) 2 @MCM‐41. In an attempt to mimic the surface chemistry, the organometallic precursors were treated with HOSi(O t Bu) 3 . The reaction of equimolar amounts of {Ba[N(SiHMe 2 ) 2 ] 2 } n and HOSi(O t Bu) 3 produced a mixed silylamido/siloxide cluster of Ba 3 [OSi(O t Bu) 3 ] 3 [N(SiHMe 2 ) 2 ] 3 with bridging‐only siloxide ligands as well as one bridging and two terminal silylamido ligands. The Schlenk equilibrium was found to govern the [Ba(AlEt 4 ) 2 ] n –HOSi(O t Bu) 3 and Mg(AlMe 4 ) 2 –HOSi(O t Bu) 3 reactions, leading to the isolation of complexes of [Ba(AlEt 4 ) 2 (toluene)] 2 and Mg[OSi(O t Bu) 3 )] 2 (AlMe 3 ) 2 , respectively. Allowing for a donor‐induced cleavage of Mg(AlMe 4 ) 2 , the reaction of [MgMe 2 ] with one or two equivalents of HOSi(O t Bu) 3 was studied. While putative Mg[OSi(O t Bu) 3 ](Me) and Mg[OSi(O t Bu) 3 ] 2 could not be crystallized from the reaction mixtures, cluster complexes Mg 5 (O)[OSi(O t Bu) 3 ] 5 Me 3 and Mg 4 (OH) 2 [OSi(O t Bu) 3 ] 6 could be unambiguously identified by X‐ray crystallography.
Interfacial electron transfer energetics studied by high spatial resolution tip-enhanced Raman spectroscopic imaging.
2011-09-05

Interfacial electron transfer (ET) in TiO2-based systems is important in artificial solar energy harvesting systems, catalysis, and in advanced oxidative waste water treatment. The fundamental importance of ET processes and impending applications make the study of interfacial ET a promising research area. Photoexcitation of dye molecules adsorbed on the surface of wide band gap semiconductors, such as TiO2, results in the injection of electrons from the dye molecules to the conduction band of the semiconductor or energetically accessible surface electronic states. Using Raman spectroscopy and ensemble-averaging approaches,t he chemical bonding and vibrational relaxation of the ET processes have been extensively studied. However, due to the complexity of the interfacial ET energetics and dynamics, significant questions remain on characterizing the source of the observed complexities. To address these important issues, we have applied advanced spectroscopic and imaging techniques such as confocal and tip-enhanced near-field Raman as well as photoluminescence spectroscopic and topographic imaging. Here we explore single surface states on TiO2 as well as the interfacial electronic coupling of alizarin to TiO2 single crystalline surfaces.
Melting and van der Waals Stabilization of PE Single Crystals Grown from Ultrathin Films
2011-09-07

We have obtained a series of single- and multilayered extended chain polyethylene (PE) crystals resting on a silicon dioxide substrate by crystallizing a low molar mass oligomer fraction of low polydispersity from an ultrathin film. Crystal thicknesses were determined from the height histograms of atomic force microscopy (AFM) images. For crystallization temperatures above 108 °C, the thickness of each layer was 16.9 ± 1.4 nm, close to the computed average extended length of the oligomer chain. The crystal melting was followed by a hot-stage optical microscopy (OM) in reflection. Different layers melt at different temperatures, due to differences in interfacial free energy depending on whether they are in contact with the substrate or another layer or have a free interface. The interfacial free energies of the different interfaces were obtained by the Gibbs–Thompson equation, and the difference between them was quantitatively related to the van der Waals stabilization energy resulting from placing a layer in contact with the substrate or with another layer. Our study demonstrates the importance of interfaces when considering the thermal behavior of ultrathin films of crystalline polymers and illustrates that a simple energetic concept can be used to explain the stabilization of crystals resting on a surface.
Depression of Release by mGluR8 Alters Ca2+ Dependence of Release Machinery
2011-09-07

The ubiquitous presynaptic metabotropic glutamate receptors (mGluRs) are generally believed to primarily inhibit synaptic transmission through blockade of Ca(2+) entry. Here, we analyzed how mGluR8 achieves a nearly complete inhibition of glutamate release at hippocampal synapses. Surprisingly, presynaptic Ca(2+) imaging and miniature excitatory postsynaptic current recordings showed that mGluR8 acts without affecting Ca(2+) entry, diffusion, and buffering. We quantitatively compared the Ca(2+) dependence of the inhibition of release by mGluR8 with the inhibition by ω-conotoxin GVIA. These calculations suggest that the inhibition produced by mGluR8 may be explained by a decrease in the apparent Ca(2+) affinity of the release sensor and, to a smaller extent, by a reduction of the maximal release rate. Upon activation of mGluR8, phasic transmitter release toward the end of a train of action potentials is greater as compared with presynaptic inhibition induced by blocking Ca(2+) entry, which is consistent with the important role of Ca(2+) in accelerating the replenishment of released vesicles. The action of mGluR8 was resistant to blockers of classical G-protein transduction pathways including inhibition of adenylate cyclase and may represent a direct effect on the release machinery. In conclusion, our data identify a mode of presynaptic inhibition which allows mGluR8 to profoundly inhibit vesicle fusion while not diminishing vesicle replenishment and which thereby differentially changes the temporal transmission properties of the inhibited synapse.
Acquired Control of Ventral Premotor Cortex Activity by Feedback Training
2011-09-08

Background. Despite the availability of various options for movement restoration in stroke patients, there is no effective treatment for patients who show little or no functional recovery of upper limb motor function. Objective. The present study explored the feasibility of real-time functional magnetic resonance imaging brain–computer interface (fMRI-BCI) as a new tool for rehabilitation of this patient population. Methods. Healthy adults and chronic subcortical stroke patients with residual movement were trained for 3 days to regulate the blood oxygenation level dependent (BOLD) response in the ventral premotor cortex (PMv), a secondary motor area with extensive anatomic connections with the primary motor cortex. Effect of learned modulation of the PMv was evaluated with BOLD signal changes across training sessions, transcranial magnetic stimulation (TMS), and a visuomotor task. Results. fMRI-BCI feedback training showed learning with a significantly increasing BOLD signal in the PMv over sessions. Participants’ capability to learn self-regulation was found to depend linearly on intracortical facilitation and correlated negatively with intracortical inhibition measured by TMS prior to feedback training. After training, intracortical inhibition decreased significantly with the volitional increase of the BOLD response in the PMv, indicating a beneficial effect of self-regulation training on motor cortical output. Conclusion. The study provides first evidence for the therapeutic potential of fMRI-BCI in stroke rehabilitation.
Protist-Type Lysozymes of the Nematode Caenorhabditis elegans Contribute to Resistance against Pathogenic Bacillus thuringiensis
2011-09-08

Pathogens represent a universal threat to other living organisms. Most organisms express antimicrobial proteins and peptides, such as lysozymes, as a protection against these challenges. The nematode Caenorhabditis elegans harbours 15 phylogenetically diverse lysozyme genes, belonging to two distinct types, the protist- or Entamoeba-type (lys genes) and the invertebrate-type (ilys genes) lysozymes. In the present study we characterized the role of several protist-type lysozyme genes in defence against a nematocidal strain of the Gram-positive bacterium Bacillus thuringiensis. Based on microarray and subsequent qRT-PCR gene expression analysis, we identified protist-type lysozyme genes as one of the differentially transcribed gene classes after infection. A functional genetic analysis was performed for three of these genes, each belonging to a distinct evolutionary lineage within the protist-type lysozymes (lys-2, lys-5, and lys-7). Their knock-out led to decreased pathogen resistance in all three cases, while an increase in resistance was observed when two out of three tested genes were overexpressed in transgenic lines (lys-5, lys-7, but not lys-2). We conclude that the lysozyme genes lys-5, lys-7, and possibly lys-2 contribute to resistance against B. thuringiensis, thus highlighting the particular role of lysozymes in the nematode's defence against pathogens.
Enhanced Pro-Inflammatory Cytokine Responses following Toll-Like-Receptor Ligation in Schistosoma haematobium-Infected Schoolchildren from Rural Gabon
2011-09-08

This pilot study shows that Schistosoma-infected children develop a more pro-inflammatory TLR2-mediated response in the face of a more anti-inflammatory adaptive immune response. This suggests that S. haematobium infection does not suppress the host's innate immune system in the context of single TLR ligation.
Relevance of the inner mitochondrial membrane enzyme F1F0‐ATPase as an autoantigen in autoimmune liver disorders
2011-09-08

Abstract Background and Aims Recently, a non‐M2‐related mitochondrial 60 kDa protein found to be recognized by antimitochondrial antibody ( AMA ) negative sera from patients with primary biliary cirrhosis ( PBC ) has been shown to contain parts of the five F 1 ‐ ATP ase subunits α, β, γ, δ and ε. In this study, we examined whether this enzyme is, indeed, a target antigen in PBC . Methods Analysed were 60 AMA ‐positive/anti‐M2‐negative and 103 anti‐M2‐positive PBC patients, 46 patients with autoimmune hepatitis ( AIH ), 35 patients with primary sclerosing cholangitis ( PSC ), 110 patients with viral hepatitis, 40 patients with inflammatory bowel diseases ( IBD ), 33 patients with connective tissue diseases (systemic lupus erythematosus, mixed connective tissue disease, S jögren disease, systemic sclerosis) and 25 blood donors. The F 1 ‐ ATP ase‐subunits α‐δ were recombinantly expressed in E scherichia coli , purified and applied to ELISA and W estern blotting. Results In all, 40 of the 60 AMA ‐positive/anti‐M2‐negative (67%) and 44 (43%) of the 103 anti‐M2‐positive PBC ‐sera reacted with at least one of the F 1 ‐subunits α‐δ. The β‐ and γ‐subunits were preferentially recognized. However, also up to 57% of patients with AIH and 34% of patients with PSC had anti‐β‐ or γ‐antibodies, while patients with viral hepatitis had these antibodies in up to 13%. Patients with IBD had anti‐β and anti‐γ‐antibodies in up to 20 and 5% respectively. None of the patients with connective tissue diseases had antibodies to the β‐ and only 6% to the γ‐subunit. Sera from healthy blood donors were negative. Conclusions Antibodies to the β‐ and γ‐subunits of F 1 ‐ ATP ase are further AMA s in PBC but occur also in other autoimmune liver disorders; they may be, therefore, indicators for a general autoimmune process of the liver.
Higher efficacy of letrozole in combination with trastuzumab compared to letrozole monotherapy as first-line treatment in patients with HER2-positive, hormone-receptor-positive metastatic breast cancer – Results of the eLEcTRA trial
2011-09-09

The eLEcTRA trial compared efficacy and safety of letrozole combined with trastuzumab to letrozole alone in patients with HER2 and hormone receptor (HR) positive metastatic breast cancer (MBC). Patients were randomized to either letrozole alone (arm A, n = 31) or letrozole plus trastuzumab (arm B, n = 26) as first-line treatment. Additional 35 patients with HER2 negative and HR positive tumors received letrozole alone (arm C). Median time to progression in arm A was 3.3 months compared to 14.1 months in arm B (hazard ratio 0.67; p = 0.23) and 15.2 months in arm C (hazard ratio 0.71; p = 0.03). Clinical benefit rate was 39% for arm A compared to 65% in arm B (odds ratio 2.99, 95% CI 1.01-8.84) and 77% in arm C (odds ratio 5.34, 95% CI 1.83-15.58). The eLEcTRA trial showed that the combination of letrozole and trastuzumab is a safe and effective treatment option for patients with HER2 positive and HR positive MBC.
Evaluation of a Thin and Mechanically Stable Collagen Cell Carrier
2011-09-09

The biological function of adherent cell populations strongly depends on the physical and biochemical properties of extracellular matrix molecules. Therefore, numerous biocompatible cell carriers have been developed to specifically influence cell attachment, proliferation, cellular differentiation, and tissue formation for diverse cell culture applications and cell-based therapies. In the present study, we evaluated the mechanical and the cell biological properties of a novel, thin, and planar collagen scaffold. The cell carrier is based on fibrillar bovine collagen type I and exhibits a low material thickness coupled with a high mechanical stability as measured by tensile tests. The influence of this new biomaterial on cell viability, proliferation, and cell differentiation was analyzed using 5-bromo-2-deoxyuridine (BrdU) proliferation assay, immunocytochemistry, water-soluble tetrazolium salt-1 assay (WST-1), live cell imaging, and electron microscopy. Cell culture experiments with the human osteosarcoma cell line Saos-2, human mesenchymal stem cells, and rodent cardiomyocytes demonstrated the in vitro biocompatibility of this chemically noncrosslinked scaffold. Both the mechanical characteristics and the in vitro biocompatibility of this collagen type I carrier facilitate the engineering of thin transferable tissue constructs and offer new possibilities in the fields of cell culture techniques, tissue engineering, and regenerative medicine.
Biomechanical Proof of Barbed Sutures for the Efficacy of Laparoscopic Pyeloplasty
2011-09-09

SRS offers immediate tissue adaption with reduced suture line shortening and equal tightness compared with nonbarbed material in vitro. Knotless suturing using SRS is time efficient and appears to be an excellent material for LPP.
Effects of atorvastatin metabolites on induction of drug‐metabolizing enzymes and membrane transporters through human pregnane X receptor
2011-09-13

BACKGROUND AND PURPOSE Atorvastatin metabolites differ in their potential for drug interaction because of differential inhibition of drug‐metabolizing enzymes and transporters. We here investigate whether they exert differential effects on the induction of these genes via activation of pregnane X receptor (PXR) and constitutive androstane receptor (CAR). EXPERIMENTAL APPROACH Ligand binding to PXR or CAR was analysed by mammalian two‐hybrid assembly and promoter/reporter gene assays. Additionally, surface plasmon resonance was used to analyse ligand binding to CAR. Primary human hepatocytes were treated with atorvastatin metabolites, and mRNA and protein expression of PXR‐regulated genes was measured. Two‐hybrid co‐activator interaction and co‐repressor release assays were utilized to elucidate the molecular mechanism of PXR activation. KEY RESULTS All atorvastatin metabolites induced the assembly of PXR and activated CYP3A4 promoter activity. Ligand binding to CAR could not be proven. In primary human hepatocytes, the para ‐hydroxy metabolite markedly reduced or abolished induction of cytochrome P450 and transporter genes. While significant differences in co‐activator recruitment were not observed, para ‐hydroxy atorvastatin demonstrated only 50% release of co‐repressors. CONCLUSIONS AND IMPLICATIONS Atorvastatin metabolites are ligands of PXR but not of CAR. Atorvastatin metabolites demonstrate differential induction of PXR target genes, which results from impaired release of co‐repressors. Consequently, the properties of drug metabolites have to be taken into account when analysing PXR‐dependent induction of drug metabolism and transport. The drug interaction potential of the active metabolite, para ‐hydroxy atorvastatin, might be lower than that of the parent compound.
Additional Use of Glycated Hemoglobin for Diagnosis of Type 2 Diabetes in People Undergoing Coronary Angiography Reveals a Subgroup at Increased Cardiovascular Risk
2011-09-13

OBJECTIVE To study the prognosis of people with newly diagnosed type 2 diabetes as per the American Diabetes Association (ADA) 2010 definition but without diabetes as per the ADA 2009 definition. RESEARCH DESIGN AND METHODS A total of 2,002 participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study without a history of diabetes were studied. RESULTS During the follow-up of a mean duration ± SD of 7.7 ± 2.0 years, 346 people died (202 cardiovascular deaths). Subjects with type 2 diabetes as per the ADA 2009 definition (n = 468) had significantly increased all-cause and cardiovascular mortality compared with people without diabetes as per the ADA 2010 definition (both P ≤ 0.003). Subjects with type 2 diabetes as per the ADA 2010 definition but without diabetes as per the ADA 2009 definition (n = 150) were at significantly increased risk to die of cardiovascular diseases (P = 0.029). CONCLUSIONS Use of the ADA 2010 diabetes definition may be instrumental in improving cardiovascular risk stratification in people undergoing coronary angiography.
The Effect of PCSK1 Variants on Waist, Waist-Hip Ratio and Glucose Metabolism Is Modified by Sex and Glucose Tolerance Status
2011-09-14

PCSK1 rs6232 G-allele and rs6235 C-allele have an effect on body composition which may be modified by sex, whereas the effect of rs6235 C-allele on fasting and stimulated circulating plasma glucose and hormone levels may be influenced by glucose tolerance status.
Heart rate variability in anorexia nervosa and the irritable bowel syndrome
2011-09-14

Opposite autonomic patterns were found in AN and IBS: stronger vagal withdrawal in IBS and weaker vagal inhibition in AN patients. Records made at rest and without any autonomic load may be representative for assessment of ANS function. Age and BMI should be taken into consideration during assessment of HRV data.
Accelerated aging phenotype in mice with conditional deficiency for mitochondrial superoxide dismutase in the connective tissue
2011-09-14

This article by Treiber et al. was published in Aging Cell. 2011; 10(2):239–54. It describes the characterization of an accelerated aging phenotype in mice, a mouse model with conditional deficiency for mitochondrial superoxide dismutase in the connective tissue. It should have been noted that Lore Florin and Peter Angel also contributed to this manuscript by providing the Col alpha2 Cre transgenic mouse model and assisting in the interpretation of the mouse phenotype. Both contributors should have been included as co-authors in this study.
Theoretical Investigation of the13C NMR Chemical Shift–NCN Angle Correlation in N‐Heterocyclic Carbenes
2011-09-14

This chapter contains sections titled: Introduction Method Validation 13C-NMR Chemical Shift –N–C–N Angle Correlation Within Various Carbene Types N–C–N Angle-Shielding Tensor Correlations: Carbene A Correlation Between N–C–N Angle and HOMO-LUMO Gap DE: Carbene A Correlations in N-Heterocyclic Carbenes References
P14.06: Extreme macrosomia (> 4.500 g): a new formula for optimized fetal weight estimation
2011-09-14

The aim of this study was to develop and to test a specific formula for estimating weight in extreme macrosomia (birth weight > 4500 g). The retrospective study was performed between 2003 and 2010. Biometric data of 174 singleton fetuses with a birth weight of > 4500 g, all examined within one week before delivery, were reviewed. Exclusion criteria were multiple pregnancy, intrauterine death, and major structural or chromosomal anomalies. The new formula was then compared with currently available weight equations. Different statistical estimation strategies were pursued. Gradient boosting with component-wise smoothing splines achieved the best results. The resulting new formula proved to be superior to established equations in terms of mean squared prediction errors, signed percentage errors, and absolute percentage errors. In addition, we derived a simple prediction rule to determine whether the newly derived formula should be applied or not. The best cut-off value proved to be an abdominal circumference above 359.712 mm (sensitivity 0.867, specificity 0.853). Our new formula provides superior weight estimation in extreme fetal macrosomia.
OP03.05: Prenatal detection of closed spina bifida
2011-09-14

To determine the position of the conus medullaris during pregnancy in relation to the last vertebral body and to examine its use to detect skin covered, closed spinal bifida. Retrospective study involving 300 consecutive ultrasound examinations between 16 weeks of gestation and term. Two operators independently assessed the images of the spine on whether the conus medullaris and the last vertebral body were visualised in one image in a midsagittal plane. The distance (conus distance/CD) between these two landmarks was measured twice by both operators, who were not aware of any previous measurements. Intra- and interobserver variability was assessed by 95% limits of agreement. Linear regression analysis was used to determine the relevant contributors to the CD and a normal range was computed based on the best-fit model. The normal results were compared with five cases of prenatally detected skin covered spinal dysraphism. In 84.7% of the 300 cases both operators were able to visualize the conus medullaris and the last vertebral body. 95% limits of agreement for the intraobserver variability were ± 1.9 mm. For the interobserver variability they were − 3.7 and 2.5 mm. We found a linear relationship of CD to gestational age, biparietal diameter and abdominal circumference. The strongest relationship was observed for femur length (CD = − 8.2+ × femur length). In the five abnormal cases, CD was well below the 5th percentile. The determination of CD allows for an objective and feasible assessment of the conus medullaris position. The parameter promises to be very useful for the prenatal detection of skin covered spinal dysraphism.
The Later Stone Age Calvaria from Iwo Eleru, Nigeria: Morphology and Chronology
2011-09-15

Our findings are in accordance with suggestions of deep population substructure in Africa and a complex evolutionary process for the origin of modern humans. They further highlight the dearth of hominin finds from West Africa, and underscore our real lack of knowledge of human evolution in that region.