bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging of Phosphatidylcholine Bilayers by a High-Pressure Fluorescence Technique: Detection of the Packing Difference
Authors: Matsuki Hitoshi , Goto Masaki , Kusube Masataka , Tamai Nobutake
Published: November 2011

The packing states in phosphatidylcholine (PC) bilayers under high pressure were studied from fluorescence measurements using a polarity-sensitive probe Prodan. By using the Prodan fluorescence data, three-dimensional image plots, which can visually evaluate the bilayer packing, were constructed for the C16PC bilayer. It turned out from the shape of contours in the image plot constructed by the second-derivative spectra that the Prodan molecules can be distributed into multiple sites in the bilayer and move around the head-group region depending on the phase state. Furthermore, comparing the plot to those for the C17PC and C18PC bilayers, the slight difference in hydrophobicity among the PC molecules produced a marked difference in quantity of the Prodan molecules distributed among the bilayer gel, nonbilayer gel, and liquid crystalline phases of the PC membranes. The present study shows that the imaging using Prodan is useful for the evaluation of lipid bilayer packing.
Delayed Acyclovir Therapy and Death Among Neonates With Herpes Simplex Virus Infection
Authors: Shah Samir S. , Aronson Paul L. , Mohamad Zeinab , Lorch Scott A.
Published: November 2011

OBJECTIVE:

To determine the association of delayed acyclovir therapy with death among neonates with herpes simplex virus (HSV) infection.

METHODS:

A multicenter, retrospective, cohort study was conducted between January 1, 2003, and December 31, 2009, with 1086 neonates (age: ≤28 days) with HSV infection from 41 tertiary care children's hospitals. Early acyclovir therapy was defined as initiation of intravenous acyclovir treatment within 1 day after hospital admission, and delayed acyclovir therapy was defined as initiation of treatment >1 and ≤7 days after hospital admission. Multivariate logistic regression models determined the association between delayed acyclovir therapy and death, with the use of propensity scores for each neonate's likelihood of receiving delayed acyclovir treatment to control for differences in illness severity between groups.

RESULTS:

The median age was 10 days. Delayed acyclovir therapy was administered to 262 neonates (24.1%). In most cases (86.2%) of delayed receipt, acyclovir administration occurred on the second or third day of hospitalization. The overall mortality rate was 7.3% (95% confidence interval: 5.8%–9.0%); 9.5% of those who received delayed acyclovir treatment and 6.6% of those who received early acyclovir treatment died. In a multivariate analysis, delayed acyclovir therapy was associated with significantly greater odds of death (adjusted odds ratio: 2.63 [95% confidence interval: 1.36–5.08]) compared with early acyclovir therapy.

CONCLUSIONS:

In this multicenter observational study of neonates with HSV infection, delayed initiation of acyclovir therapy was associated with in-hospital death. Our data support the use of empiric acyclovir therapy for neonates undergoing testing for HSV infection.
Clarithromycin in Preventing Bronchopulmonary Dysplasia in Ureaplasma urealyticum–Positive Preterm Infants
Authors: Ozdemir Ramazan , Erdeve Omer , Dizdar Evrim Alyamac , Oguz Serife Suna , Uras Nurdan , Saygan Sibel , Karabulut Erdem , Dilmen Ugur
Published: November 2011

OBJECTIVE:

To evaluate the efficacy and safety of clarithromycin treatment in preventing bronchopulmonary dysplasia (BPD) in Ureaplasma urealyticum–positive preterm infants.

PATIENTS AND METHODS:

Nasopharyngeal swabs for U urealyticum culture were taken from infants with a birth weight between 750 and 1250 g in the first 3 postnatal days. Infants with a positive culture for U urealyticum were randomly assigned to 1 of 2 groups to receive either intravenous clarithromycin or placebo. All the patients were followed at least up to the 36th postmenstrual week.

RESULTS:

A total of 224 infants met the eligibility criteria of the study. Seventy-four (33%) infants had a positive culture for U urealyticum in the first 3 day cultures. The rate of BPD development was significantly higher in patients with U urealyticum positivity (15.9% vs 36.4%; P < .01). However, multivariate logistic regression analysis failed to reveal a significant association between the presence of U urealyticum and BPD development (odds ratio: 2.4 [95% confidence interval: 0.9–6.3]; P = .06). Clarithromycin treatment resulted in eradication of U urealyticum in 68.5% of the patients. The incidence of BPD was significantly lower in the clarithromycin group than in the placebo group (2.9% vs 36.4%; P < .001). Multivariate logistic regression analysis confirmed the independent preventive effect of clarithromycin for the development of BPD (odds ratio: 27.2 [95% confidence interval: 2.5–296.1]; P = .007).

CONCLUSIONS:

Clarithromycin treatment prevents development of BPD in preterm infants who are born at 750 to 1250 g and colonized with U urealyticum.
Endoplasmic Reticulum Stress Inhibits STAT3-Dependent Suppression of Hepatic Gluconeogenesis via Dephosphorylation and Deacetylation
Authors: Kimura Kumi , Yamada Tomoko , Matsumoto Michihiro , Kido Yoshiaki , Hosooka Tetsuya , Asahara Shun-ichiro , Matsuda Tomokazu , Ota Tsuguhito , Watanabe Hiroshi , Sai Yoshimichi , Miyamoto Kenichi , Kaneko Shuichi , Kasuga Masato , Inoue Hiroshi
Published: November 2011

In the liver, signal transducer and activator of transcription 3 (STAT3) plays an important role in the suppression of gluconeogenic enzyme expression. While obesity-associated endoplasmic reticulum (ER) stress has been shown to increase hepatic gluconeogenic enzyme expression, the role of ER stress in STAT3-dependent regulation of such expression is unclear. The current study aimed to elucidate the effect of ER stress on the STAT3-dependent regulation of hepatic gluconeogenic enzyme expression. Genetically obese/diabetic db/db mice and db/db mouse–derived isolated hepatocytes were used as ER stress models. A tyrosine phosphatase inhibitor, a deacetylation inhibitor, and an acetylated mutant of STAT3 were used to examine the effect of ER stress on hepatic STAT3 action. ER stress inhibited STAT3-dependent suppression of gluconeogenic enzyme gene expression by suppressing hepatic Janus kinase (JAK)2 and STAT3 phosphorylation. A tyrosine phosphatase inhibitor restored ER stress–induced suppression of JAK2 phosphorylation but exhibited no improving effect on suppressed STAT3 phosphorylation. STAT3 acetylation is known to correlate with its phosphorylation. ER stress also decreased STAT3 acetylation. An acetylated mutant of STAT3 was resistant to ER stress–induced inhibition of STAT3-phosphorylation and STAT3-dependent suppression of hepatic gluconeogenic enzyme gene expression in vitro and in vivo. Trichostatin A, a histone deacetylase (HDAC) inhibitor, ameliorated ER stress–induced inhibition of STAT3 acetylation and phosphorylation. The current study revealed that ER stress inhibits STAT3-dependent suppression of hepatic gluconeogenic enzymes via JAK2 dephosphorylation and HDAC-dependent STAT3 deacetylation, playing an important role in the increase of hepatic glucose production in obesity and diabetes.
Na+-d-glucose Cotransporter SGLT1 is Pivotal for Intestinal Glucose Absorption and Glucose-Dependent Incretin Secretion
Authors: Gorboulev Valentin , Schürmann Annette , Vallon Volker , Kipp Helmut , Jaschke Alexander , Klessen Dirk , Friedrich Alexandra , Scherneck Stephan , Rieg Timo , Cunard Robyn , Veyhl-Wichmann Maike , Srinivasan Aruna , Balen Daniela , Breljak Davorka , Rexhepaj Rexhep , Parker Helen E. , Gribble Fiona M. , Reimann Frank , Lang Florian , Wiese Stefan , Sabolic Ivan , Sendtner Michael , Koepsell Hermann
Published: November 2011

To clarify the physiological role of Na+-d-glucose cotransporter SGLT1 in small intestine and kidney, Sglt1−/− mice were generated and characterized phenotypically. After gavage of d-glucose, small intestinal glucose absorption across the brush-border membrane (BBM) via SGLT1 and GLUT2 were analyzed. Glucose-induced secretion of insulinotropic hormone (GIP) and glucagon-like peptide 1 (GLP-1) in wild-type and Sglt1−/− mice were compared. The impact of SGLT1 on renal glucose handling was investigated by micropuncture studies. It was observed that Sglt1−/− mice developed a glucose-galactose malabsorption syndrome but thrive normally when fed a glucose-galactose–free diet. In wild-type mice, passage of d-glucose across the intestinal BBM was predominantly mediated by SGLT1, independent the glucose load. High glucose concentrations increased the amounts of SGLT1 and GLUT2 in the BBM, and SGLT1 was required for upregulation of GLUT2. SGLT1 was located in luminal membranes of cells immunopositive for GIP and GLP-1, and Sglt1−/− mice exhibited reduced glucose-triggered GIP and GLP-1 levels. In the kidney, SGLT1 reabsorbed ∼3% of the filtered glucose under normoglycemic conditions. The data indicate that SGLT1 is 1) pivotal for intestinal mass absorption of d-glucose, 2) triggers the glucose-induced secretion of GIP and GLP-1, and 3) triggers the upregulation of GLUT2.
Counting What Counts
Authors: Fritz Julie M. , MacDermid Joy C. , Snyder-Mackler Lynn
Published: November 2011

This month's issue of JOSPT contains a bibliometric analysis of the publishing history of the Journal of Orthopaedic & Sports Physical Therapy. The results provide an opportunity to reflect on trends at JOSPT and, more generally, in the evidence base of orthopaedic and sports physical therapy practice. Results of the bibliometric review by Coronado and colleagues are encouraging for JOSPT and the profession of physical therapy as a whole. The results indicate an increase in the publication of research articles involving symptomatic subjects, with fewer narrative and nonsystematic review papers. The results also raise an interesting issue about whether we have a sufficient number of randomized controlled trials in our literature and to what extent our future progress should be based on the publication of more randomized trials.

J Orthop Sports Phys Ther 2011;41(12):907–908. doi:10.2519/jospt.2011.0110
New Modes for the Prediction of Gas Chromatographic Relative Retention Times of Polybrominated Diphenyl Ethers
Authors: Yi Zhongsheng , Li Lianchen , Zhang Aiqian , Wang Liansheng
Published: November 2011

A series of quantitative structure‐retention relationship models were developed to predict gas chromatographic relative retention times (GC‐RRTs) for 209 polybrominated diphenyl ether (PBDE) congeners on 10 stationary phases. A genetic algorithm with twofold leave‐multiple‐out cross validation (LMOCV) was used to select optimal subsets from large‐size molecular descriptors. Overall multiple‐linear regression fitting correlation coefficients (R2) are greater than 0.988, except for the CP‐Sil 19 column, in which QLMOCV2 (correlation coefficient of LMOCV), QLOOCV2 (correlation coefficient of leave‐one‐out cross validation, LOOCV), and Rpre2 (correlation coefficients of prediction set) are larger than 0.98. The excellent statistical parameters reveal that the models are robust and have high internal and external predictive capability. According to the descriptors for constructing the models, the GC‐RRTs in various stationary phases are highly dependent on distances among atoms, branches of molecules, and molecular properties. PBDE congeners with 1, 9, and 10 bromines are major outliers based on the results of the application domain.
Low‐Temperature Heat Capacities and Standard Molar Enthalpy of Formation of Gramine (C11H14N2)
Authors: Chen Jingtao , Kong Yuxia , Di Youying , Yang Weiwei , Tan Zhicheng
Published: November 2011

Low‐temperature heat capacities of gramine (C11H14N2) were measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 401 K. A polynomial equation of heat capacities as a function of temperature was fitted by least squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at 5 K intervals. The constant‐volume energy of combustion of the compound at T=298.15 K was measured by a precision oxygen‐bomb combustion calorimeter as ΔcU=−(35336.7±13.9) J·g−1. The standard molar enthalpy of combustion of the compound was determined to be ΔcHm0=−(6163.2±2.4) kJ·mol−1, according to the definition of combustion enthalpy. Finally, the standard molar enthalpy of formation of the compound was calculated to be Δ;cHm0=−(166.2±2.8) kJ·mol−1 in accordance with Hess law.
Synthesis of Multifunctional Mn‐Doped CdTe/ZnS Core/Shell Quantum Dots
Authors: Lü Jianquan , Lü Shiyan , Ye Tai , Zhou Xingwang
Published: November 2011

The synthesis of a novel water‐soluble Mn‐doped CdTe/ZnS core‐shell quantum dots using a proposed ultrasonic assistant method and 3‐mercaptopropionic acid (MPA) as stabilizer is descried. To obtain a high luminescent intensity, post‐preparative treatments, including the pH value, reaction temperature, reflux time and atmosphere, have been investigated. For an excellent fluorescence of Mn‐doped CdTe/ZnS, the optimal conditions were pH 11, reflux temperature 100°C and reflux time 3 h under N2 atmosphere. While for phosphorescent Mn‐doped CdTe/ZnS QDs, the synthesis at pH 11, reflux temperature 100°C and reflux time 3 h under air atmosphere gave the best strong phosphorescence. The characterizations of Mn‐doped CdTe/ZnS QDs were also identified using AFM, IR, powder XRD and thermogravimetric analysis. The data indicated that the photochemical stability and the photoluminescence of CdTe QDs are greatly enhanced by the outer inorganic ZnS shell, and the doping Mn2+ ions in the as‐prepared quantum dots contribute to strong luminescence. The strong luminescence of Mn‐doped CdTe/ZnS QDs reflected that Mn ions act as recombination centers for the excited electron‐hole pairs, attributing to the transition from the triplet state (4T1) to the ground state (6A1) of the Mn2+ ions. All the experiments demonstrated that the surface states played important roles in the optical properties of Mn‐doped CdTe/ZnS core‐shell quantum dots.
Storage Stability of LiFePO4/C in Humid‐hot Air
Authors: Guo Xiangfeng , Zuo Jun , Zhan Hui , Zhou Yunhong
Published: November 2011

Storage stabilities of LiFePO4/C composite at different conditions are investigated in terms of structural and electrochemical evolutions. The results from different aging tests indicate that moisture and temperature are the key factors that have the most profound effects on the structure homogeneity which in turn influences the electrochemical performance of LiFePO4/C. Although the storage in a humid‐hot environment, such as saturated humidity air at 50°C, does not greatly influence the discharging capacity of LiFePO4/C, it does reduce the initial charging capacity, thus the amount of reversible Li+ ions in a practical LiFePO4/graphite cell decreases. This impact is explained by the lithium extraction during the storage, forming olivine FePO4 and associated Li3PO4. Elevated storage temperature also favors the delithiation process. The degree of delithiation increases from about 6% at 50°C to 18% at 80°C. It is also found that re‐calcination at 650°C effectively resolves the problem of the structural heterogeneity of the stored LiFePO4/C. Therefore both the initial charging capacity and coulombic efficiency of the stored sample in the first cycle revert to the original value of the fresh one.
Convenient Synthesis of Terminal Alkynes from anti‐3‐Aryl‐2,3‐dibromopropanoic Acids Using a K2CO3/DMSO System
Authors: Cheng Xuezhi , Jia Jun , Kuang Chunxiang
Published: November 2011

A convenient, efficient, and generally applicable method was developed for the synthesis of terminal alkynes from anti‐3‐aryl‐2,3‐dibromopropanoic acids in the presence of DMSO and K2CO3.
Preparation of Silica‐bonded Propyl‐diethylene‐triamine‐N‐sulfamic Acid as a Recyclable Catalyst for Chemoselective Synthesis of 1,1‐Diacetates
Authors: Nouri Sefat Maryam , Deris Abdolah , Niknam Khodabakhsh
Published: November 2011

A simple and efficient procedure for the preparation of silica‐bonded propyl‐diethylene‐triamine‐N‐sulfamic acid (SPDTSA) by reaction of 3‐diethylenetriamine‐propylsilica (DTPS) and chlorosulfonic acid in chloroform is described. Silica‐bonded propyl‐diethylene‐triamine‐N‐sulfamic acid is employed as a recyclable catalyst for the synthesis of 1,1‐diacetates from aromatic aldehydes and acetic anhydride under mild and solvent‐free conditions at room temperature. Catalyst could be recycled for several times without any additional treatment.
A Novel Chemiluminescence Immunoassay Using Solid‐Phase Antigen for Free 17β‐Estradiol in Human Serum
Authors: Qi Yuanyuan , Chen Hui , Lin Zhen , Chen Guonan , Lin Jinming
Published: November 2011

A high‐performance chemiluminescence immunoassay, with long‐term durability, good precision and time‐saving, was proposed for the detection of free 17β‐estradiol (E2) in human serum. Ninety‐six microplates were coated with bovine serum albumin conjugated E2 antigen as solid phase for the immunoassay. The E2‐BSA antigen coated on the microplate and the E2 antigen in the sample competed for the binding sites on the horseradish peroxidase (HRP) labeled anti‐E2 antibody. Chemiluminescence reaction was subsequently carried out by HRP catalyzing luminol‐H2O2 substrates, and the chemiluminescence intensity was inversely proportional to the amount of analyte in human sera samples. The concentration of immunoreagents, immunoreaction time, and other relevant variable conditions upon the immunoassay were studied and optimized. The proposed method exhibited detection limit as low as 5.94×10−3 µg·L−1 in a linear detection range from 0.01 to 1.00 µg·L−1, good recoveries between 105% and 108%, and high precision with intra‐ and inter‐assay coefficients between 7.9% and 14.3%.
Phase Diagram of Na2S2O3)+t‐Butanol+Water at Ambient Pressure and Temperature
Authors: Sabale Sandip R.
Published: November 2011

In the present work, we report the studies concerning liquid‐liquid‐solid equilibria for the ternary system sodium thiosulphate (Na2S2O3)+t‐butanol+water at ambient pressure and at room temperature (303±2 K). The solubility data of Na2S2O3 are reported for solutions in water, t‐butanol and solutions of varying concentrations of t‐butanol in water. The phase diagram for the said system is developed, described and compared with similar systems studied such as Na2S2O3+ethanol+water, K2CO3+methanol+water, etc. These results have been explained in terms of structural properties of aqueous t‐butanol solutions and further discussed in terms of the effect of ions to cause phase separation.
Micromagnetic study of current-pulse-induced magnetization switching in magnetic tunnel junctions with antiferromagnetically and ferromagnetically coupled synthetic free layers
Authors: Yoshida Chikako , Min Lee Young , Ochiai Takao , Uehara Yuji , Sugii Toshihiro
Published: November 2011

We investigated the dynamics of current-pulse-induced magnetization switching in magnetic tunnel junctions (MTJs) with antiferromagnetically and ferromagnetically coupled synthetic free layers through micromagnetic simulations. We found that a magnetic vortex is formed in thick upper ferromagnetic layers and plays an important role in magnetization switching in both types of synthetic free layers. Furthermore, higher thermal stability is observed in an MTJ with the ferromagnetically coupled free layer at an annealing temperature of 250 °C.
p53 Negatively Regulates Transcription of the Pyruvate Dehydrogenase Kinase Pdk2
Authors: Contractor Tanupriya , Harris Chris R.
Published: November 2011

In cancer cells, the aberrant conversion of pyruvate into lactate instead of acetyl-CoA in the presence of oxygen is known as the Warburg effect. The consequences and mechanisms of this metabolic peculiarity are incompletely understood. Here we report that p53 status is a key determinant of the Warburg effect. Wild-type p53 expression decreased levels of pyruvate dehydrogenase kinase-2 (Pdk2) and the product of its activity, the inactive form of the pyruvate dehydrogenase complex (P-Pdc), both of which are key regulators of pyruvate metabolism. Decreased levels of Pdk2 and P-Pdc in turn promoted conversion of pyruvate into acetyl-CoA instead of lactate. Thus, wild-type p53 limited lactate production in cancer cells unless Pdk2 could be elevated. Together, our results established that wild-type p53 prevents manifestation of the Warburg effect by controlling Pdk2. These findings elucidate a new mechanism by which p53 suppresses tumorigenesis acting at the level of cancer cell metabolism. Cancer Res; 72(2); 560–7. ©2011 AACR.
Post-translational modification of RNase R is regulated by stress-dependent reduction in the acetylating enzyme Pka (YfiQ)
Authors: Liang Wenxing , Deutscher Murray P.
Published: November 2011

RNase R is a processive exoribonuclease that plays an important role in degradation of structured RNAs in Escherichia coli. RNase R is unstable in exponential phase cells; however, under certain stress conditions, RNase R levels increase dramatically due to its stabilization. Binding of tmRNA and SmpB to the C-terminal region of RNase R is required for its instability, and this binding is regulated by acetylation of a single residue, Lys544, in exponential phase cells. RNase R is not acetylated in stationary phase. We show here that only exponential phase RNase R is acetylated because the modifying enzyme, protein lysine acetyltransferase, Pka (YfiQ), is absent from late exponential and stationary phase cells. As a consequence, newly synthesized RNase R remains unmodified. Together with the turnover of preexisting acetylated RNase R, no modified RNase R remains in stationary phase. We find that RNase R in cold-shocked cells also lacks the acetyl modification due to the absence of Pka. These data indicate that RNase R stability depends on Pka, which itself is regulated under stress conditions.
Characteristics of Global Solar Radiation Monitor Utilizing Solar Cells
Authors: Ibrahim A. , Ramadan M. R. I.
Published: November 2011

This brief note examines the characteristics of solar cells from the standpoint of developing a global solar radiation monitor. The study is performed using a simplified photovoltaic test monitor manufactured, a single crystal p-type czochraliski (CZ) silicon solar cell of the construction n+pp++ passivated emitter solar cell coupled to a fluke 73 digital multimeter. The short circuit current density (Jsc) is examined during a complete test day from 8:40 AM to 7:40 PM. Subsequently, the test monitor is used for checking the accuracy of transfer operations of solar radiation. The results obtained by the test monitor utilizing solar cells are good due to: (a) it is simple in construction, (b) it exhibits a good response to all solar radiation variations, and (c) it works without an electric power supply.
High-resolution X-ray computed tomography for 3D microstructure characterization of a cellulose particle filled polymer foam
Authors: Kastner Johann , Kickinger Richard , Salaberger Dietmar
Published: November 2011

Due to the excellent strength/weight ratio, good energy absorbing ability, superior thermal, and acoustic insulation properties together with reasonable costs, polymer foams are the material of choice for many applications. The incorporation of particulate or fibrous fillers can even improve the properties. In this article, we investigate an open-cell polyurethane foam filled with cellulose particles. This is a new moisture-absorbing wood–plastic composite used for special mattresses. The foam was characterized by high-resolution cone-beam X-ray computed tomography (XCT) with voxel sizes between 0.7 µm3 and 2.2 µm3. The XCT measurements were performed with a tube voltage of 50 kV to obtain enough contrast. The XCT data were processed by various algorithmic steps (e.g., smoothing, thresholding, watershed transformation, erosion, dilation, and feature extraction) to ascertain the three-dimensional open-cell structure together with particle distribution, size, and position. Quantitative data for the cells (mean diameter, shape, volume, and position), for the cellulose particles (mean diameter, shape, volume, and position), for the polymer vertices (shape and position) and for combinations of them (e.g., distance between particles and vertices) were derived from the XCT data. 15.2 cells/mm3, 41 cellulose particles/mm3, and 88.7 polymer vertices/mm3 were found. The average diameter value for the mostly globular cells was found to be 465 µm with a Gaussian-like distribution function. The cellulose particles are globular and elongated and the distribution resembles an exponential function where 95% of the particles have diameters below 60 µm. The particles are situated within the polymer walls and close to the surface. The function for the distance of the particles from the closest vertices corresponds to a Weibull distribution function with a scale parameter of 53 µm and a shape parameter of 1.7.
Antecedents of Organizational Citizenship Behavior Among Educators in Language Education for Adult Immigrants in Norway
Authors: Elstad Eyvind , Christophersen Knut-Andreas , Turmo Are
Published: November 2011

Organizational citizenship behavior (OCB) is discretionary and is neither directly nor explicitly recognized by the formal reward system. OCB promotes the efficient and effective functioning of a school organization. The purpose of this article is to explore the antecedents of OCB among educators of adult immigrants in Norway and to examine the relative impact of these aspects on OCB. The study is rooted in theories that have their focal point in employees’ perceptions of exchange. The methodology involved was a cross-sectional survey of 764 educators. The structural equation analysis indicated that factors such as relational trust between the leader and educators and perceptions of social exchange have a strong positive effect on the educators’ OCB. The article concludes with a discussion of how social practice among educators and school leaders is mobilized for sustained extra-role behavior that is advantageous to the organization.
Mechanistic Study of the Palladium-Catalyzed Stereoselective Cross-Coupling Reaction of 1,1-Dibromo-3,3,3-trifluoro-2-tosyloxypropene
Authors: Shimizu Masaki , Takeda Youhei , Hiyama Tamejiro
Published: November 2011

We prepared a Pd complex by the oxidative addition of 1,1-dibromo-3,3,3-trifluoro-2-tosyloxypropene to [Pd(PPh3)4]. The atomic distance between Pd and F in the complex was 2.95 Å, which was shorter than the sum of the van der Waals radii, suggesting that Pd–F interaction played an important role in determining the stereochemical outcome of the Pd-catalyzed cross-coupling reaction of the propene.
Preterm Milk Oligosaccharides During the First Month of Lactation
Authors: Gabrielli Orazio , Zampini Lucia , Galeazzi Tiziana , Padella Lucia , Santoro Lucia , Peila Chiara , Giuliani Francesca , Bertino Enrico , Fabris Claudio , Coppa Giovanni V.
Published: November 2011

OBJECTIVE:

Oligosaccharides represent one of the main components of human milk, and they have been assigned important biological functions for newborns. Qualitatively and quantitatively, their presence in milk is strictly related to the expression of the mother's Se and/or Le genes, on the basis of which 4 different milk groups have been described. The aim of the study was to provide new data on the oligosaccharide composition of preterm milk in relation to the 4 groups.

METHODS:

High-pH anion-exchange chromatography was used to quantify levels of 23 oligosaccharides and lactose in 252 milk samples collected from 63 mothers during the first month of lactation and to identify the 4 milk groups.

RESULTS:

Substantial differences in oligosaccharide contents were found within the groups and were strictly related to the presence or absence of specific fucosyl-oligosaccharides. The highest concentration was found in group 1 (>20 g/L), the lowest level was found in group 4 (∼10 g/L), and intermediate values were observed in groups 2 and 3. No statistically significant differences in lactose concentrations were observed among the groups.

CONCLUSIONS:

Our data confirm lower lactose concentrations in preterm milk, compared with term milk, and they provide the first detailed characterization of oligosaccharides in preterm milk, demonstrating important differences in oligosaccharide contents in the 4 groups. These differences might exert an influence on several biological functions that are particularly important for preterm infants and currently are attributed to milk oligosaccharides.
Layered Al‐substituted Cobalt Hydroxides/GO Composites for Electrode Materials of Supercapacitors
Authors: Chen Yanli , Hu Zhongai , Chang Yanqin , Wang Huanwen , Fu Guorui , Jin Xiaoqing , Xie Lijing
Published: November 2011

In this work, Al‐substituted α‐Co(OH)2/GO composites with supercapacitive properties were prepared by chemical co‐precipitated method in which cobalt nitrate and aluminum nitrate were used as the raw material, and graphite oxide was employed as carrier. The as‐prepared materials were characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and fourier transform infrared spectroscopy (FT‐IR). Cyclic voltammetry (CV) and galvanostatic charge/discharge measurements showed that the Al‐substituted α‐Co(OH)2/GO electrode material had excellent electrochemical capacitance. The specific capacitance of 1137 F·g−1 was achieved in 6 mol/L KOH solution at a current density of 1 A·g−1 within a potential range of 0–0.5 V. Moreover, only 12% losses of the initial specific capacitance were found after 500 cycles at a current density of 1 A·g−1.
A New Framework for Viewing the Philosophy, Principles and Practice of Systems Science
Authors: Wilby Jennifer
Published: November 2011

In this essay, a new framework for viewing the philosophy, principles and practice of systems science is proposed for furthering research and practice into transdisciplinary forms of intervention. This new framework reveals the effect of the interactions between systems principles and system structure in revealing complex systems behavior, demonstrates why such methodologies are classed as being systemic, and how these systemic methodologies can be used to explore, design and manage new transdisciplinary practice. Copyright © 2011 John Wiley & Sons, Ltd.
Scanning tunneling microscopic studies of laser-induced modifications of Si(001)-(2 × 1) surface
Authors: Yasui Kosuke , Kanasaki Jun’ichi
Published: November 2011

Scanning tunneling microscopic studies of Si(001)-2 × 1 surfaces excited with 532-nm laser pulses of intensities below melting and ablation thresholds have revealed two different modes of structural modifications, strongly depending on the intensity of laser lights. The excitation below 100 mJ/cm2 causes bond rupture at individual dimer-sites leading to the formation of vacancies selectively on the outermost layer. The bond rupture, which shows a strongly site-sensitive rate, forms efficiently vacancy-strings elongated along the surface dimer-rows. Selective removal of surface dimers results in the exposure of flat and defect-less underlying layer as reported previously, which is resistive to the excitation at this range of intensity. At intensities above 100 mJ/cm2, on the other hand, the excitation forms not only vacancies but also ad-dimers on terraces. The number density of ad-dimers is in proportion to the square of that for vacancies, indicating strongly that silicon atoms released by laser-induced bond rupture are associated with each other to form ad-dimers. The repeated irradiations at this range of intensities induce anisotropic growth of ad-dimer islands and of vacancy clusters on terrace regions, leading to multiply terraced structure. The primary processes of the structural modifications are discussed based on the quantitative analyses of the growth of vacancy and ad-dimer under excitation.
Determination of chemical specific atomic interaction with scanning tunneling microscope
Authors: Deshpande Aparna , Felix Braun Kai , Hla Saw-Wai
Published: November 2011

We present an experimental technique to comparatively determine the shape of tip-atom interaction potential and interaction strength of individual atoms on a surface using a scanning tunnelling microscope. From the atom manipulation signals, the tip-atom force vector angle is measured as a function of distance. Remarkably, the force angle is found to increase linearly with reducing tip-height for a small distance variation, which enables to deduce the shape of tip-atom interaction potential, and the lateral force required to move individual atoms on a surface. This technique will be useful to comparatively determine interaction strengths of molecules and biomolecular systems on surfaces.
Morphometric differentiation of Pseudocalanus minutus populations in the Barents Sea
Authors: Dvoretsky Vladimir G. , Dvoretsky Alexander G.
Published: November 2011

Dvoretsky VG. and Dvoretsky AG. 2011. Morphometric differentiation of Pseudocalanus minutus populations in the Barents Sea. —Acta Zoologica (Stockholm) 00: 1–12.

We investigated spatial variations in the morphometric characteristics (total length of body, lengths of cephalothorax, abdomen and antennules, and their relative proportions) of Pseudocalanus minutus, an abundant copepod species across the Barents Sea in August–September 2007. Females were found to have higher values for the measured parameters than males. The average absolute morphometric characters of both sexes increased from the south to the north. In most cases, parameters were similar in the southern, central, and eastern regions delineated by cluster analyses of oceanographic variables. The morphometric characteristics were strongly correlated with environmental variables in both males and females. Multiple regression analysis showed that temperature together with salinity explained 72–85% (in females) and 38–91% (in males) of the total variations in the log10‐transformed morphometric parameters. According to principal component analysis and discriminant function analysis, two distinct groups could be separated in the Barents Sea. The first group included the copepods from the northern region; the other included populations from the southern, central, and eastern regions. The observed morphological variation can be interpreted as geographical variation connected with hydrological variability.
Early Pregnancy Loss in an Era of “Wrongful Embryonic Death”
Authors: Wilcox Allen J. , Ikemoto Lisa C.
Published: June 2024

This Viewpoint examines the possible legal consequences of pregnancy loss following the Alabama Supreme Court’s decision to extend personhood to laboratory-conceived embryos.
Women’s Representation in RCTs Evaluating FDA-Supervised Medical Devices
Authors: Epstein Nitzan Karny , Harpaz Maya , Abo-Molhem Mohamad , Yehuda Daniel , Tau Noam , Yahav Dafna
Published: June 2024

This systematic review evaluates the representation of women in randomized clinical trials (RCTs) of US Food and Drug Administration (FDA)–supervised medical devices.
Semantic Representation of Low‐Cycle‐Fatigue Testing Data Using a Fatigue Test Ontology and ckan.kupferdigital Data Management System
Authors: Nasrabadi Hossein Beygi , Hanke Thomas , Skrotzki Birgit
Published: June 2024

Addressing a strategy for publishing open and digital research data, this article presents the approach for streamlining and automating the process of storage and conversion of research data to those of semantically queryable data on the web. As the use case for demonstrating and evaluating the digitalization process, the primary datasets from low‐cycle‐fatigue testing of several copper alloys are prepared. The fatigue test ontology (FTO) and ckan.kupferdigital data management system are developed as two main prerequisites of the data digitalization process. FTO has been modeled according to the content of the fatigue testing standard and by reusing the basic formal ontology, industrial ontology foundry core ontology, and material science and engineering ontology. The ckan.kupferdigital data management system is also constructed in such a way that enables the users to prepare the protocols for mapping the datasets into the knowledge graph and automatically convert all the primary datasets to those machine‐readable data which are represented by the web ontology language. The retrievability of the converted digital data is also evaluated by querying the example competency questions, confirming that ckan.kupferdigital enables publishing open data that can be highly reused in the semantic web.
Self‐Regulated Growth of Large‐Grain Sb2S3 Thin Films for High‐Efficiency Solar Cells
Authors: Chen Shihang , Wang Xiaomin , Chen Xueling , Zhao Yuqi , Dai Guohao , Yang Junjie , Tang Rongfeng , Chen Tao , Hu Pu , Li Jianmin
Published: June 2024

Antimony sulfide (Sb2S3) has attracted extensive attention due to its excellent photoelectric characteristics, including a high absorption coefficient (α > 104 cm−1) and a suitable bandgap (≈1.7 eV). However, due to its Q1D (quasi‐1D) structure, numerous deep‐level defects are identified in the Sb2S3 film, limiting the device's performance, and necessitating more efforts to overcome this situation. In this context, an ethanol solvent‐assisted chemical bath deposition (S‐CBD) strategy, a novel high‐quality thin film manufacturing technique is presented that modifies the supersaturation of the precursor solution by varying the boiling point and solvent polarity. This approach enables the effective regulation of the correlation between the crystal nucleation and growth rates, resulting in Sb2S3 films with large grains (≈4.25 µm, 37.5% ethanol), excellent crystallinity, well‐oriented structures (TC(211)/TC(020) = 2.39), low defect density, and prolonged carrier lifetimes (τAve ≈ 12.1 ns). Consequently, the final Sb2S3‐based solar device (FTO/CdS/Sb2S3/Spiro‐OMeTAD/Au) shows significant improvements in both FF (61.63%) and JSC (17.61 mA cm−2), yielding an excellent power conversion efficiency (PCE) of 7.84%. This research gives particular insights into the growth mechanism of high‐quality Sb2S3 thin films by CBD method as well as a potential route for enhancing Sb2S3 solar cell performance.
Advanced Polymer Materials for Protecting Lithium Metal Anodes of Liquid‐State and Solid‐State Lithium Batteries
Authors: Li Zhenghao , Zheng Yun , Liao Can , Duan Song , Liu Xiang , Chen Guohui , Dong Li , Dong Jie , Ma Chunxiang , Yin Bo , Yan Wei , Zhang Jiujun
Published: June 2024

Lithium metal batteries (LMBs) are considered as one type of the most promising next‐generation energy storage devices with high‐energy‐density, and stabilizing the lithium metal anodes (LMAs) to overcome LMBs’ safety concerns and performance degradation has attracted extensive attention. Introducing advanced polymer materials into the critical components of LMBs has proven to be an effective and promising approach for stabilizing LMAs toward practical application of LMBs. In addressing the lack of a timely review on the emerging progress of advanced polymer materials in LMBs for stabilizing LMAs, a comprehensive article summarizing the most recent developments of multiscale cellulose materials, including micron cellulose (MC) and nanocellulose (NC), in LMBs is reviewed. First, the basic structures of cellulose, characteristics comparison, and the development history of introducing cellulose into LMBs are presented. Furthermore, the roles of multiscale cellulose materials and functional mechanisms in various components of LMBs for stabilizing LMAs are summarized. A general conclusion and a perspective on the current limitations and future research directions of cellulose‐based stable LMBs are proposed. The aim of this review is not only to summarize the recent progress of multiscale cellulose materials in stabilizing LMAs but also to lighten the pathways for realizing LMBs’ practical application.
Chiral Polymer‐Organic Molecule Composite with Circularly Polarized Thermally Activated Delayed Fluorescence and Room‐Temperature Phosphorescence by Bridging Effect of Hydrogen Bond
Authors: Chen Ruilian , Feng Rui , Huang Zhenjie , Feng Dengchong , Long YuBo , Zhang Jiawen , Yang Yuzhao , Ma Zetong , Yuan Zhongke , Lu Shaolin , Zhao Zujin , Chen Xudong
Published: June 2024

Circularly polarized luminescence is essential to chiral and photonic science, but achieving circularly polarized thermally activated delayed fluorescence (CP‐TADF) and circularly polarized room‐temperature phosphorescence (CP‐RTP) simultaneously remains a great challenge. This is because it is difficult to satisfy simultaneously the stable triplet exciton, appropriate energy gap, and the regular chiral environment. Herein, a simple strategy is reported to construct a persistent photoluminescent system, which can achieve TADF and RTP simultaneously by suppressing the non‐radiative transition decay of the triplet exciton through intermolecular hydrogen bonding between acridine flavin (AF) and rigid polymer network. The persistent photoluminescent composite exhibited ultra‐long lifetimes and high quantum yields. Then, a rarely multi‐circularly polarized photoluminescence system containing CP‐TADF and CP‐RTP is constructed by the co‐assembly of cellulose nanocrystals, polyvinyl alcohol, and AF. By utilizing the cholesteric structure, photonic band gap of chiral photonic crystals, and the stabilization mechanism of triplet exciton by intermolecular hydrogen bonding between the light emitter and rigid polymer, chiral photoluminescent films exhibited rare optical properties simultaneously: multi‐circularly polarized photoluminescence emission, high and tunable dissymmetric factor, significant quantum yield, and ultralong lifetimes, which are not reported before and broaden the perspective for multi‐circularly polarized luminescence.
Compressively Strained and Interconnected Platinum Cones with Greatly Enhanced Activity and Durability toward Oxygen Reduction
Authors: Liu Mingkai , Zhou Siyu , Figueras‐Valls Marc , Ding Yong , Lyu Zhiheng , Mavrikakis Manos , Xia Younan
Published: June 2024

The synthesis of cone‐shaped Pt nanoparticles featuring compressively‐strained {111} facets by depositing Pt atoms on the vertices of Pd icosahedral nanocrystals, followed by selective removal of the Pd template via wet etching, is reported. By controlling the lateral dimensions down to ca. 3 nm, together with a thickness of ca. 2 nm, the Pt cones show greatly enhanced specific and mass activities toward oxygen reduction, with values being 2.8 and 6.4 times those of commercial Pt/C, respectively. Both the strain field and the observed activity trend are rationalized using density functional theory calculations. With the formation of ultrathin linkers among the Pt cones derived from the same Pd icosahedral seed, the interconnected Pt cones acquire stronger interactions with the carbon support, preventing them from detachment and aggregation during the catalytic reaction. Even after 20 000 cycles of accelerated durability test, the Pt cones still show a mass activity 5.3 times higher than the initial value of the Pt/C.
Optical Switchers to Manipulate Intracellular Pathways and Boost Tissue Regeneration
Authors: Dell’Aversano Natalia , Amenta Maria Laura , Rippa Massimo , Moros Maria , Tino Angela , Tortiglione Claudia
Published: June 2024

The possibility to remotely manipulate intracellular pathways in single cells is among the current goals of regenerative medicine, demanding new strategies to enhance tissue repair and reprogram stem cell activity. Plasmonic nanomaterials are addressing this need, due to improvements in the controlled synthesis allowing convenient regulation and precise thermal positioning. Leveraging on the thermal properties of gold nanoprisms (AuNPs) and on the unparalleled regenerating capabilities of the small invertebrate Hydra vulgaris, here the possibility to activate the molecular machinery underlying the animal regeneration by using AuNPs and applying regular pulses of near infrared irradiation (NIR) is shown. The efficiency of the head regeneration, reproductive capability, and stem cell proliferation rate are boosted by the AuNP photostimulation, indicating NIR triggered hyperthermia as new tool to enhance tissue regeneration. By transcriptional profiling of key developmental genes in animals exposed to external heat or irradiated an estimation of the heat developed in vivo by intracellular nanoheaters is obtained, revealing Hydra as a living thermometer to test performance of plasmonic materials. These results shed light on a novel function of heat emitting nanoparticles to control cell stemness through the activation of molecular pathways that can be targeted for regenerative medicine or wound healing strategies.
Understanding and Design of Cathode–Electrolyte Interphase in High‐Voltage Lithium–Metal Batteries
Authors: Li Wanxia , He Zixu , Jie Yulin , Huang Fanyang , Chen Yawei , Wang Yuan , Zhang Wenqiang , Zhu Xingbao , Cao Ruiguo , Jiao Shuhong
Published: June 2024

The development of lithium–metal batteries (LMBs) has emerged as a mainstream approach for achieving high‐energy‐density energy storage devices. The stability of electrochemical interfaces plays an essential role in realizing stable and long‐life LMBs. Despite extensive and comprehensive research on the lithium anode interface, there is limited focus on the cathode interface, particularly regarding high‐voltage transition metal oxide cathode materials. In this review, the challenges associated with developing stable high‐voltage cathode materials are first discussed. Characterization techniques for understanding the composition and structure of the cathode–electrolyte interphase (CEI) are then introduced. Subsequently, recent developments in electrolyte design and interface modification for constructing a stable CEI are summarized. Finally, perspectives on future research trends for understanding and developing the high‐voltage CEI are discussed. This review can offer valuable guidance for understanding and designing the high‐voltage CEI, pushing forward the development of high‐energy‐density LMBs.
In Situ Interphasial Engineering Enabling High‐Rate and Long‐Cycling Li Metal Batteries
Authors: Li Chenrui , Yang Chengwei , Huang Tianrun , Wang Yuehua , Yang Junhe , Jiang Yong , Mao Jianfeng , Zheng Shiyou , Xia Shuixin
Published: June 2024

The practical implementation of Li metal anode has long been hindered by the significant challenges of notorious dendritic Li growth and severe interphase instability during repeated cycling. Herein, a highly lithiophilic NiSe‐modified host has rationally been constructed to stabilize Li metal by the facile mechanical rolling strategy. The in situ configurated high‐flux Li2Se‐enriched interphase layer can facilitate the fast interfacial charge transfer, high Li plating/stripping reversibility and homogeneous Li nucleation/growth. Consequently, the achieved modified Li metal demonstrates ultrahigh rate capability (10 mA cm−2) and ultralong‐term cycling stability (6600 cycles) with dendrite‐free Li deposition. The Li|LiFePO4 (LFP) cell exhibits an extraordinarily long lifespan cycling stability over 500 cycles with an ultra‐low decay rate of only ≈0.0092% per cycle at 1 C. Furthermore, the 4.5 V high‐voltage Li|LiCoO2 pouch cell with a high areal capacity (≈1.9 mAh cm−2) still reveals an impressively prolonged cyclability over 200 cycles even under the harsh test condition of low negative‐to‐positive‐capacity (N/P) ratio of ≈3.4 and lean electrolyte of ≈5.5 µL mAh−1. This work provides a facile and scalable strategy toward a highly stable Li metal anode for reliable practical usage.