bluuebunny/crossref_metadata_2025 huggingface dataset:
Overfitting, generalization, and MSE in class probability estimation with high‐dimensional data
Authors: Kim Kyung In , Simon Richard
Published: December 2013

Accurate class probability estimation is important for medical decision making but is challenging, particularly when the number of candidate features exceeds the number of cases. Special methods have been developed for nonprobabilistic classification, but relatively little attention has been given to class probability estimation with numerous candidate variables. In this paper, we investigate overfitting in the development of regularized class probability estimators. We investigate the relation between overfitting and accurate class probability estimation in terms of mean square error. Using simulation studies based on real datasets, we found that some degree of overfitting can be desirable for reducing mean square error. We also introduce a mean square error decomposition for class probability estimation that helps clarify the relationship between overfitting and prediction accuracy.
Outcomes of antibiotic prophylaxis in acute cholecystectomy in a population-based gallstone surgery registry
Authors: Jaafar G , Persson G , Svennblad B , Sandblom G
Published: December 2013

Background

The aim of this study was to assess the effect of antibiotic prophylaxis (AP) on postoperative infections in acute cholecystectomy.

Methods

The study was based on acute cholecystectomies registered in the nationwide Swedish Register for Gallstone Surgery and Endoscopic Retrograde Cholangiopancreatography (GallRiks) between 2006 and 2010. The association between AP and the risk of postoperative infectious complications was tested in a multivariable regression analysis, with stepwise addition of age, sex, duration of operation, indication for surgery, surgical approach (laparoscopic versus open) and American Society of Anesthesiologists (ASA) fitness grade as co-variables. Postoperative infections requiring antibiotic treatment and postoperative abscesses were defined as outcome measures.

Results

AP was given to 9549 (68·6 per cent) of 13 911 patients. Postoperative infections requiring antibiotic treatment occurred following 1070 procedures (7·7 per cent), including 805 patients (8·4 per cent) who received AP (P < 0·001 versus patients without AP). Postoperative abscesses developed after 273 procedures (2·0 per cent), including 208 patients (2·2 per cent) who received AP (P = 0·007). In univariable analysis, the odds ratio for development of infectious complications necessitating treatment with antibiotics was 1·42 (95 per cent confidence interval 1·23 to 1·64) for those who received APversus those who did not, and for postoperative abscesses it was 1·47 (1·11 to 1·95). In multivariable analysis, adjusting for confounders, the odds ratios were 0·93 (0·79 to 1·10) and 0·88 (0·64 to 1·21) respectively.

Conclusion

The present study suggests that AP provides no benefit in acute cholecystectomy.
Effect of delaying same-admission cholecystectomy on outcomes in patients with diabetes
Authors: Gelbard R , Karamanos E , Teixeira P G , Beale E , Talving P , Inaba K , Demetriades D
Published: December 2013

Background

Recent studies have suggested that same-admission delayed cholecystectomy is a safe option. Patients with diabetes have been shown to have less favourable outcomes after cholecystectomy, but the impact of timing of operation for acute cholecystitis during the same admission is unknown.

Methods

This was a retrospective analysis of patients undergoing laparoscopic cholecystectomy for acute cholecystitis between 2004 and 2010, from the American College of Surgeons National Surgical Quality Improvement Program database. Patients with no significant co-morbidities (American Society of Anesthesiologists grade I or II) were included. Propensity score matching (PSM) was used to match patients with diabetes with those who did not have diabetes, in a ratio of 1 : 3, to ensure homogeneity of the two groups. Logistic regression models were applied to adjust for differences between early (within 24 h) and delayed (24 h or more) surgical treatment. The primary outcome was development of local and systemic infectious complications. Secondary outcomes were duration of operation and length of hospital stay.

Results

From a total of 2892 patients, 144 patients with diabetes were matched with 432 without diabetes by PSM. Delaying cholecystectomy for at least 24 h after admission in patients with diabetes was associated with significantly higher odds of developing surgical-site infections (adjusted odds ratio 4·11, 95 per cent confidence interval 1·11 to 15·22; P = 0·034) and a longer hospital stay. For patients with no diabetes, however, delaying cholecystectomy had no impact on complications or length of hospital stay.

Conclusion

Patients with diabetes who undergo laparoscopic cholecystectomy 24 h or more after admission may have an increased risk of postoperative surgical-site infection and a longer hospital stay than those undergoing surgery within 24 h of admission.
Deformation of nuclei and abnormal spindles assembly in the second male meiosis of polyploid tobacco plants
Authors: Sidorchuk Yu. V. , Deineko E. V.
Published: December 2013

The bipolar spindle is a major cytoskeletal structure, which ensures an equal chromosome distribution between the daughter nuclei. The spindle formation in animal cells depends on centrosomes activity. In flowering plant cells the centrosomes have not been identified as definite structures. The absence of these structures suggests that plants assemble their spindle via novel mechanisms. Nonetheless, the cellular and molecular mechanisms controlling the cytoskeleton remodeling during the spindle development in plants are still insufficiently clear. This article describes the results of a comparative analysis of the microtubular cytoskeleton dynamics during assembly of the second division spindle in tobacco microsporocytes with the normal and deformed nuclei. According to our observations, the bipolar spindle fibres are formed from short arrays of the disintegrated perinuclear cytoskeleton system, the perinuclear microtubular band. The microsporocytes of polyploid tobacco plants with deformed nuclei entirely lack this cytoskeleton structure. In such type of cells the overall prometaphase events are blocked, and the assembly of second division spindles is completely arrested.
The Photochemical Reaction of Vinylaziridines and Vinylazetidines with Chromium(0) and Molybdenum(0) (Fischer) Carbene Complexes
Authors: Rivero Alexandra R. , Fernández Israel , Sierra Miguel A.
Published: December 2013

The [5+2] and [6+2] cycloaddition reactions of vinylaziridines and vinylazetidines with ketenes generated photochemically from chromium(0) and molybdenum(0) Fischer carbene complexes have been investigated. These processes constitute a straightforward and efficient route to azepanones and azocinones, respectively. The peculiar electronic properties of the metalated ketenes allow for the introduction of electron‐rich substituents in the final cycloadducts, a difficult task using conventional organic chemistry procedures. The versatility of the process is demonstrated by using Cr0 Fischer bis(carbene) complexes as metalated bis(ketene) precursors. These species produce tethered bis(azepanone)s in a single step under mild reaction conditions. Density functional theory calculations point to a stepwise reaction pathway through the initial nucleophilic attack of the nitrogen atom of the aziridine on the metalated ketene, followed by ring closure of the zwitterionic intermediate formed.
New 2,6‐Distyryl‐Substituted BODIPY Isomers: Synthesis, Photophysical Properties, and Theoretical Calculations
Authors: Gai Lizhi , Mack John , Lu Hua , Yamada Hiroko , Kuzuhara Daiki , Lai Guoqiao , Li Zhifang , Shen Zhen
Published: December 2013

A 2,6‐distyryl‐substituted boradiazaindacene (BODIPY) dye and a new series of 2,6‐p‐dimethylaminostyrene isomers containing both α‐ and β‐position styryl substituents were synthesized by reacting styrene and p‐dimethylaminostyrene with an electron‐rich diiodo‐BODIPY. The dyes were characterized by X‐ray crystallography and NMR spectroscopy and their photophysical properties were investigated and analyzed by carrying out a series of theoretical calculations. The absorption spectra contain markedly redshifted absorbance bands due to conjugation between the styryl moieties and the main BODIPY fluorophore. Very low fluorescence quantum yields and significant Stokes shifts are observed for 2,6‐distyryl‐substituted BODIPYs, relative to analogous 3,5‐distyryl‐ and 1,7‐distyryl‐substituted BODIPYs. Although the fluorescence of the compound with β‐position styryl substituents on both pyrrole moieties and one with both β‐ and α‐position substituents was completely quenched, the compound with only α‐position substituents exhibits weak emission in polar solvents, but moderately intense emission with a quantum yield of 0.49 in hexane. Protonation studies have demonstrated that these 2,6‐p‐dimethylaminostyrene isomers can be used as sensors for changes in pH. Theoretical calculations provide strong evidence that styryl rotation and the formation of non‐emissive charge‐separated S1 states play a pivotal role in shaping the fluorescence properties of these dyes. Molecular orbital theory is used as a conceptual framework to describe the electronic structures of the BODIPY core and an analysis of the angular nodal patterns provides a reasonable explanation for why the introduction of substituents at different positions on the BODIPY core has markedly differing effects.
Iron‐Catalyzed Imidative Kinetic Resolution of Racemic Sulfoxides
Authors: Wang Jun , Frings Marcus , Bolm Carsten
Published: December 2013

Kinetic resolution of racemic sulfoxides requires either custom substrates or shows moderate enantioselectivity, leading to achiral coproducts (such as sulfones) as an intrinsic part of the process. A new strategy is demonstrated that allows the resolution of racemic sulfoxides through catalytic asymmetric nitrene‐transfer reactions. This approach gives rise to both optically active sulfoxides and highly enantioenriched sulfoximines. By using a chiral iron catalyst and a readily available iodinane reagent, high selectivity factors have been achieved under very practical reaction conditions. With respect to the substrate scope, it is noteworthy that this unprecedented imidative kinetic resolution of racemic sulfoxides provides access to both aryl–alkyl and dialkyl sulfoximines in highly enantioenriched forms.
Isolatable Organophosphorus(III)–Tellurium Heterocycles
Authors: Nordheider Andreas , Chivers Tristram , Schön Oliver , Karaghiosoff Konstantin , Athukorala Arachchige Kasun S. , Slawin Alexandra M. Z. , Woollins J. Derek
Published: December 2013

A new structural arrangement Te3(RPIII)3 and the first crystal structures of organophosphorus(III)–tellurium heterocycles are presented. The heterocycles can be stabilized and structurally characterized by the appropriate choice of substituents in Tem(PIIIR)n (m=1: n=2, R=OMes* (Mes*=supermesityl or 2,4,6‐tri‐tert‐butylphenyl); n=3, R=adamantyl (Ad); n=4, R=ferrocene (Fc); m=n=3: R=trityl (Trt), Mesor by the installation of a PV2N2 anchor in RPIII[TePV(tBuN)(μ‐NtBu)]2 (R=Ad, tBu).
Peptide Conjugates for Directing the Morphology and Assembly of 1D Nanoparticle Superstructures
Authors: Zhang Chen , Song Chengyi , Fry H. Christopher , Rosi Nathaniel L.
Published: December 2013

Designed peptide conjugates molecules are used to direct the synthesis and assembly of gold nanoparticles into complex 1D nanoparticle superstructures with various morphologies. Four peptide conjugates, each based on the gold‐binding peptide (AYSSGAPPMPPF; PEPAu), are prepared: C12H23O‐AYSSGAPPMPP (1), C12H23O‐AYSSGAPPMPPF (2), C12H23O‐AYSSGAPPMPPFF (3), and C12H23O‐AYSSGAPPMPPFFF (4). The affect that C‐terminal hydrophobic F residues have on both the soft‐assembly of the peptide conjugates and the resulting assembly of gold nanoparticle superstructures is examined. It is shown that the addition of two C‐terminal F residues (3) leads to thick, branched 1D gold nanoparticle superstructures, whereas the addition of three C‐terminal F residues (4) leads to bundling of thin 1D nanoparticle superstructures.
Hydrodynamics of turbulent bed contactor with non‐Newtonian liquids: Net pressure drop and minimum fluidisation velocity (part 2)
Authors: Abukhalifeh Hadil , Fayed Muhammed E. , Bhagat Nirav , Dhib Ramdhane
Published: December 2013

The study investigates the hydrodynamic behaviour of non‐Newtonian liquids under different operating conditions in a turbulent bed contactor (TBC). Hollow plastic spheres were fluidised in an air stream flowing counter currently to an aqueous solution of carboxy methyl cellulose (CMC) of an apparent viscosity ranging from 5 to 25 mPa s. A set of experiments was carried out to investigate the net pressure drop and minimum fluidisation velocity of the process. The column was operated at different superficial gas velocities, liquid flow rates, CMC solution concentrations and static bed heights. Results show that the net pressure drop is independent of the superficial gas velocity, but it increases steadily with liquid flow rate and static bed height. However, it remains almost invariant with a relatively low CMC concentration (0.2–0.4 wt%), and it augments gradually as the CMC percent exceeds the threshold of 0.4 wt% which corresponds to a more viscous liquid solution. The minimum fluidisation velocity decreases with a CMC concentration lower than 0.5 wt% approximately, but increases as the CMC percent exceeds 0.5 wt%. The study presents a new insight on the behaviour of non‐Newtonian solutions in TBC columns.
Fate and Behavior of Pollutants in a Vegetated Pond System for Road Runoff
Authors: Roinas Georgios , Tsavdaris Alexandros , Williams John B. , Mant Catherine
Published: December 2013

Road runoff contains a variety of contaminants that threaten aquatic systems. Pollutant mitigation is therefore an important function of sustainable drainage systems such as vegetated ponds. Vegetated ponds have a variety of treatment mechanisms that potentially can remove different pollutants. However, design is predominantly based on “black box” approaches. This study monitored a swale and vegetated pond receiving road runoff over two years to investigate the interaction of various pollutant removal processes. Storm runoff, pond water, and sediments were monitored for general water quality, metals, hexane extractable hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). A non‐exponential “first flush” was apparent for biochemical oxygen demand, chemical oxygen demand, and solids with higher concentrations seen during the early stages of storms; however, for hydrocarbons and PAHs peak concentrations were often seen later in storm events. Due to interference from natural compounds, PAHs are probably more appropriate than hexane extracts for tracking runoff pollutant fate. Pyrene, despite having low concentrations in water, accumulated in soils and sediments (median = 850 µg/g). Naphthalene was more mobile, but was effectively removed in the pond. Metals had similar concentrations to other studies, with large removals of particularly Cu and Zn. However, metals exhibited different deposition patterns, with Zn and Cu accumulating in pond inlet sediments and Ni and Cr accumulating at the outlet. The different behaviors and fates of pollutants means that refining design guidance is difficult and requires consideration of how specific mechanisms may be enhanced for prioritizing removal of pollutants that pose the greatest risk.
The ULAB colour space
Authors: Kim Dong‐Ho
Published: December 2013

A new colour space, named ULAB, is developed. It is derived from the CIELAB colour space and can be converted to and from CIELAB. Unlike modified CIELAB colour‐difference formulae, ULAB incorporates corrections for lightness, chroma, and hue differences into its colour coordinates. For the small magnitude colour difference data, it shows the performance as good as more complicated formulae such as CIEDE2000. ULAB shows another chance of developing a colour space approximately more uniform than CIELAB. © 2013 Wiley Periodicals, Inc. Col Res Appl, 40, 17–29, 2015
Polarimetry as a Tool for the Study of Solutions of Chiral Solutes
Authors: Orlova Anna V. , Andrade Renato R. , da Silva Clarissa O. , Zinin Alexander I. , Kononov Leonid O.
Published: December 2013

Optical rotation of aqueous solutions of D‐levoglucosan was studied experimentally in the 0.03–4.0 mol L−1 concentration range and a nonlinear concentration dependence of specific optical rotation (SR) was revealed. Discontinuities observed in the concentration plot of SR (at 0.1, 0.3, 0.5, 1.0, and 2.0 mol L−1) are well correlated with those found by static and dynamic light scattering and identify concentration ranges in which different solution domains (supramers) may exist. The average SR experimental value for a D‐levoglucosan aqueous solution ([α]D28 −58.5±8.7 deg dm−1 cm−3 g−1) was found to be in good agreement with values obtained by theoretical calculation (TD‐DFT/GIAO) of SR for 15 different conformers revealed by conformational sampling at the PCM/B3LYP/6‐311++G(2d,2p)//B3LYP/6‐31+G(d,p) level, which were shown to be strongly affected by the solvation microenvironment (0, 1, 2, and 3 explicit solvent molecules considered) due to local geometrical changes induced in the solute molecule. This exceptionally high sensitivity of SR makes polarimetry a unique method capable of sensing changes in the structure of supramers detected in this study.
Polyols and Polyurethanes from the Liquefaction of Lignocellulosic Biomass
Authors: Hu Shengjun , Luo Xiaolan , Li Yebo
Published: December 2013

Polyurethanes (PUs), produced from the condensation polymerizations between polyols and isocyanates, are one of the most versatile polymer families. Currently, both polyols and isocyanates are largely petroleum derived. Recently, there have been extensive research interests in developing bio‐based polyols and PUs from renewable resources. As the world’s most abundant renewable biomass, lignocellulosic biomass is rich in hydroxyl groups and has potential as a feedstock to produce bio‐based polyols and PUs. Lignocellulosic biomass can be converted to liquid polyols for PU applications through acid‐ or base‐catalyzed atmospheric liquefaction processes using polyhydric alcohols as liquefaction solvents. Biomass liquefaction‐derived polyols can be used to prepare various PU products, such as foams, films and adhesives. The properties of biomass liquefaction‐derived polyols and PUs depend on various factors, such as feedstock characteristics, liquefaction conditions, and PU formulations.
Yellow‐Emitting Sr9Sc(PO4)7:Eu2+, Mn2+ Phosphor with Energy Transfer for Potential Application in White Light‐Emitting Diodes
Authors: Dong Xiaoling , Zhang Jiahua , Zhang Liangliang , Zhang Xia , Hao Zhendong , Luo Yongshi
Published: December 2013

Eu2+–Mn2+ codoped yellow‐emitting Sr9Sc(PO4)7 (SSP) phosphors have been synthesized by solid‐state reactions. The synthesis, structure refinement, and luminescence properties of the obtained phosphor were investigated in detail. The obtained phosphor exhibits a strong excitation band between 250 and 450 nm, matching well with the dominant emission band of a near‐UV light‐emitting‐diode (LED) chip. Upon excitation at 365 nm, the Sr9Sc(PO4)7:Eu2+, Mn2+ phosphor shows strong yellow emissions centered at 510 and 610 nm. The energy transfer mechanism from Eu2+ to Mn2+ in Sr9Sc(PO4)7:Eu2+, Mn2+ has been studied and demonstrated to be a resonant type through a dipole‐quadrupole mechanism based on the decay lifetime data. These results indicate that yellow‐emitting Sr9Sc(PO4)7:Eu2+, Mn2+ can serve as a promising candidate for application in white‐light LEDs.
The Measurement of the Gibbs Energy of Transfer Between Oil and Water Using a Nano‐Carbon Paste Electrode
Authors: Gan Patrick , Lowinsohn Denise , Foord John S , Compton Richard G
Published: December 2013

The use of nano‐carbon paste electrodes for the measurement of Gibbs energies of transfer between oil and aqueous phases is reported. In this method the oil of interest is used as the binder for the nano‐carbon paste electrodes and the molecule of interest is dissolved in the organic or aqueous phase. Voltammetry is performed over a period of time and used to monitor the transfer of the molecule between the two phases. The method is illustrated for the transfer of ferrocenemethanol between water and oil using the ferrocenemethanol / ferroceniummethanol (FcCH2OH/FcCH2OH+) redox couple. Three pairs of voltammetric peaks were observed in a 0.1 M KCl solution when the nano‐carbon paste electrode was modified by dissolution of FcCH2OH in the binder oil: P1 [E=0.23 V, 0.17 V vs. Ag/AgCl (1 M KCl)], P2 [E=0.36 V, 0.32 V vs. Ag/AgCl (1 M KCl)] and P3 [E=0.55 V, 0.46 V vs. Ag/AgCl (1 M KCl)]. These are assigned to the FcCH2OH species existing in the aqueous solution [FcCH2OH(aq)/FcCH2OH+(aq)], originating in the oil (o) [FcCH2OH(o)/FcCH2OH+(aq)] and to oxidation of adsorbed (ads) material on the nano‐carbon [FcCH2OH(ads)] respectively. When supporting electrolyte containing the anions Cl−, NO3− or SCN− was used, an expulsion of the oxidised ferrocene occurred and the difference in midpoint potentials (Emid) between the peaks P1 and P2 observed in these experiments allowed the calculation of the Gibbs energy (ΔG°) of transfer of ferrocenemethanol from water to oil. The average ΔG° value thus obtained was (−12.7±0.2) kJ mol−1. For more hydrophobic anions (X−=PF6−, AsF6−), the electron transfer is coupled to the transfer of the anion into the oil and the ΔG° for the transfer of the ion pair of FcCH2OH+ and X− ions from water to oil was found to be −1.3 and −3.9 kJ mol−1 for PF6− and AsF6− respectively.
Multiplexed Determination of Amino‐Terminal Pro‐B‐Type Natriuretic Peptide and C‐Reactive Protein Cardiac Biomarkers in Human Serum at a Disposable Electrochemical Magnetoimmunosensor
Authors: de Ávila Berta Esteban‐Fernández , Escamilla‐Gómez Vanessa , Lanzone Valentina , Campuzano Susana , Pedrero María , Compagnone Dario , Pingarrón José M.
Published: December 2013

A rapid magnetoimmunosensor for the simultaneous determination of two cardiac biomarkers, amino‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) and C‐reactive protein (CRP), in human serum is described. Specific capture antibodies were covalently immobilized onto carboxylic acid‐modified magnetic beads. The quantification of NT‐proBNP and CRP was performed by using indirect competitive and sandwich configurations, respectively, and horseradish peroxidase‐labeled tracers. The use of dual screen‐printed carbon electrodes allowed the achievement of simultaneous independent amperometric readout for each cardiac biomarker. The developed methodology showed very low limits of detection (0.47 ng mL−1). An international standard for CRP serum spiked with NT‐proBNP was analyzed to evaluate the usefulness of the magnetoimmunosensor.
Participation in biobanks for research by incapacitated adults: review and discussion of current guidelines
Authors: Togni Elena , Dierickx Kris , Porteri Corinna
Published: December 2013

Objective

Biobanks for research and genetic research are important opportunities to create new understanding of complex disorders, such as psychiatric disorders and dementia. The management of biobanks for subjects with psychiatric disorders or dementia raises additional challenges because of the ethical issues regarding the potentially impaired decision‐making capacities of the subjects. The aim of this paper is to study (i) how guidelines address the matter and (ii) how they can be implemented in real research situations with patients suffering from psychiatric disorders and dementia.

Method

We collected and analysed all the relevant guidelines and position papers from national and international organizations dealing with research on biological materials and selected documents mentioning the participation of incapacitated adults in genetic research and biobanks.

Results

Eighteen of the 30 analysed documents contain explicit references to adults who are unable to give consent. The main topics addressed by the guidelines are the following: (i) informed consent; (ii) principles of non‐therapeutic research; and (iii) ethics committee review.

Conclusions

In biomedical research, guidelines are an important instrument for facilitating research while promoting subjects' rights and well‐being. Compared with legally binding documents, guidelines are more flexible and can be more easily revised according to evolving research situations and for adaptation to real persons and research settings. We suggest measures to implement the analysed guidelines taking into consideration the case for the participation of patients with neuropsychiatric disorders, who can have impairment of decision‐making capacities without being obviously incompetent, in genetic research and biobanks. Copyright © 2013 John Wiley & Sons, Ltd.
High Glucose Condition Suppresses Neurosphere Formation by Human Periodontal Ligament‐Derived Mesenchymal Stem Cells
Authors: Sawangmake Chenphop , Pavasant Prasit , Chansiripornchai Piyarat , Osathanon Thanaphum
Published: December 2013

D‐Glucose serves many roles in cellular functions, but its role in human periodontal ligament‐derived mesenchymal stem cells (hPSLSCs) is yet unknown. Here, the roles of high glucose concentration on neurogenic differentiation by hPDLSCs were investigated. Two‐stage neurogenic induction protocol was employed. Cells were maintained in normal neurogenic induction medium, high glucose condition, or high mannose condition. The results showed that high glucose attenuated neurosphere formation efficiency by hPDLSCs in terms of morphology, neurogenic marker expression, without a deleterious effect on cell viability. Contrastingly, neurosphere‐derived cells matured in high glucose condition exhibited normal neuronal characteristics compared to the control. During neurosphere formation in high glucose, glucose transporters (GLUTs) mRNA levels were significantly decreased, corresponding with the deprivation of cellular glucose uptake. Further, a glucose uptake inhibitor, cytochalasin B, was used to confirm the deleterious effects of glucose uptake deprivation during neurosphere formation. The results demonstrated that deprivation of glucose uptake attenuated neurosphere formation efficiency by hPDLSCs. Together, the results illustrated that high glucose condition attenuated the efficiency of neurosphere formation but not neuronal maturation, which may occur through the downregulation of GLUTs and the reduction of glucose uptake. J. Cell. Biochem. 115: 928–939, 2014. © 2013 Wiley Periodicals, Inc.
Fenretinide Induces Ubiquitin‐Dependent Proteasomal Degradation of Stearoyl‐CoA Desaturase in Human Retinal Pigment Epithelial Cells
Authors: Samuel William , Kutty R. Krishnan , Duncan Todd , Vijayasarathy Camasamudram , Kuo Bryan C. , Chapa Krysten M. , Redmond T. Michael
Published: December 2013

Stearoyl‐CoA desaturase (SCD, SCD1), an endoplasmic reticulum (ER) resident protein and a rate‐limiting enzyme in monounsaturated fatty acid biosynthesis, regulates cellular functions by controlling the ratio of saturated to monounsaturated fatty acids. Increase in SCD expression is strongly implicated in the proliferation and survival of cancer cells, whereas its decrease is known to impair proliferation, induce apoptosis, and restore insulin sensitivity. We examined whether fenretinide, (N‐(4‐hydroxyphenyl)retinamide, 4HPR), which induces apoptosis in cancer cells and recently shown to improve insulin sensitivity, can modulate the expression of SCD. We observed that fenretinide decreased SCD protein and enzymatic activity in the ARPE‐19 human retinal pigment epithelial cell line. Increased expression of BiP/GRP78, ATF4, and GADD153 implicated ER stress. Tunicamycin and thapsigargin, compounds known to induce ER stress, also decreased the SCD protein. This decrease was completely blocked by the proteasome inhibitor MG132. In addition, PYR41, an inhibitor of ubiquitin activating enzyme E1, blocked the fenretinide‐mediated decrease in SCD. Immunoprecipitation analysis using anti‐ubiquitin and anti‐SCD antibodies and the blocking of SCD loss by PYR41 inhibition of ubiquitination further corroborate that fenretinide mediates the degradation of SCD in human RPE cells via the ubiquitin–proteasome dependent pathway. Therefore, the effect of fenretinide on SCD should be considered in its potential therapeutic role against cancer, type‐2 diabetes, and retinal diseases. J. Cell. Physiol. 229: 1028–1038, 2014. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Synthesis of Biologically Important N‐Heteroaryl‐2‐(heteroarylthio)acetamides
Authors: Krishnaraj Thulasiraman , Muthusubramanian Shanmugam
Published: December 2013

The synthesis of compounds having triazole and selena/thiadiazole rings connected by a chain having sulfur and nitrogen in the link has been described. The resultant N‐heteroaryl‐2‐(heteroarylthio)acetamide may be biologically important as related compounds found application in the inhibition of HIV 1 replications.
Unexpected Synthesis of a 5H‐chromeno[3,4‐c]pyridine Derivative from 4‐Chlorocoumarin‐3‐carbaldehyde and Malononitrile
Authors: Ivanov Ivo C. , Angelova Violina T. , Tiritiris Ioannis , Glasnov Toma
Published: December 2013

In the reaction of 4‐chlorocoumarin‐3‐carbaldehyde with malononitrile in the presence of piperidine, a piperidinium salt of a novel tricyclic chromeno[3,4‐c]pyridine derivative was isolated instead of the expected “tert‐amino effect” product. When hexamethyleneimine (azepane) was used as a base, the corresponding azepanium salt (same anion) was obtained. Both structures have been formulated on the basis of their spectral (IR, NMR, MS) behavior and elemental analyses. In addition, the structure of the piperidinium salt was confirmed by means of X‐ray crystallographic analysis.
Improved and Efficient Synthesis of Chromeno[4,3‐d]pyrazolo [3,4‐b]pyridin‐6(3H)‐ones and Their Fluorescence Properties
Authors: Liu Xue‐Cheng , Lin Wei , Wang Hui‐Yan , Huang Zhi‐Bin , Shi Da‐Qing
Published: December 2013

A series of chromeno[4,3‐d]pyrazolo[3,4‐b]pyridin‐6(3H)‐one derivatives was easily and efficiently synthesized by the reaction of 2H‐chromen‐2‐ones with pyrazol‐5‐amines catalyzed by CuCl2⋅2H2O in ethanol. This protocol has the advantages of mild reaction conditions, easy work‐up, and high yields. These compounds were showed to have high fluorescence quantum yields, which mentioned their value as luminescence or fluorescence probe.
Making Numbers Come to Life: Two Scoring Methods for Creativity in Aurora's Cartoon Numbers
Authors: Tan Mei , Mourgues Catalina , Bolden David S. , Grigorenko Elena L.
Published: December 2013

Although creativity has long been recognized as an important aspect of mathematical thinking, both for the advancement of the field and in students' developing expertise in mathematics, assessments of student creativity in that domain have been limited in number and focus. This article presents an assessment developed for creativity that provides a score for mathematical creativity (MaC) in addition to a score for general creativity in the numeric domain, or what we might call numerical creativity (NuC). We developed different rating scales for each and then explored how each scoring method accounts for the students' mathematical/numerical and creative skills. The psychometric properties for both scoring approaches were examined. Each method was shown to reflect different relationships with other performance tests. In addition, it is proposed that MaC may provide useful insight into students' levels of adaptive expertise in mathematics, as reflected by their ability to apply mathematical knowledge (i.e., language, operations, concepts) to novel situations, representing an informative supplement to performance indicators of math achievement.
Managing Knowledge through Video‐Based Communities
Authors: Kodama Mitsuru
Published: December 2013

This article proposes that video‐based information network (VIN) tools as a type of social software are a form of infrastructure that promotes the creation of new knowledge that transcends space and time in business activities. The first of two new insights discussed in the article concerns the effects of diverse communication and collaboration provided by VIN tools. Real‐time communication and collaboration enabled by VIN tools, which combine and process images, sound, and data, result in creating particular modes of use of VIN tools specific to the company using them. The second insight is the formation of new business networks and the facilitation of knowledge creation activities through the use of VIN tools.

The article considers four elements of information and communications technology (ICT) organizational capability that promote knowledge creation activities through these particular modes of use of VIN tools: ICT application capability, creative dialogue capability, context architect capability, and boundary consolidation capability. It also illustrates that the dynamic relationship of these four elements promotes the formation of business networks and the formation, maintenance, and development of knowledge communities and leads to new knowledge creation. Copyright © 2013 John Wiley & Sons, Ltd.
Going Practical on the Core Competence Concept: On Links, Levels, Time and Context
Authors: Ljungquist Urban
Published: December 2013

We update the original core competence notions of identification and development to fit high efficient innovation processes in dynamic environments, with aim to progress the concept's applicability for scholars and practitioners.

To the core competence concept we add four dimensions previously missing: time (shared history and shared future aims), managerial hierarchy levels (corporate and SBU), innovation development modes and outcome types (radical/incremental and exploitation/exploration), and finally innovation team characteristics and support structure (homogenous/heterogeneous and formal/informal structure).

We propose that existing core competencies are ideally explored by homogenous teams managed at the SBU‐level, in structured context, which infers competitive imitation protection. The process starts with identification then progressed by a change in structure: going from formal to informal, which will increase core competence and company performance.

Copyright © 2013 John Wiley & Sons, Ltd.
The effects of prematurity on incidence of aspiration following supraglottoplasty for laryngomalacia
Authors: Anderson de Moreno Lauren C. , Matt Bruce H.
Published: December 2013

Objectives

To determine if patients who were born premature have a higher incidence of aspiration following supraglottoplasty compared to patients born full term.

Study Design

Retrospective study.

Methods

Two thousand three hundred sixty (2360) patient charts from Riley Hospital for Children were reviewed retrospectively. Patients had already been treated for laryngomalacia with supraglottoplasty by Dr. Bruce Matt. Estimated weeks gestational age at birth was recorded for each patient. Prematurity was stratified as mild (32–36 weeks gestational age [WGA]), very (28–31 WGA), or extremely (<28 WGA). Patients were excluded from the study if they had suspected aspiration with chronic cough, pneumonia, chronic lung disease, or documented aspiration prior to supraglottoplasty.

Results

As previously shown, 75 patients (3.2%) had aspiration following supraglottoplasty. Twenty of these patients were preterm infants at birth. The rate for aspiration following supraglottoplasty for former premature infants was statistically significant (5.9%, odds ratio = 2.3,P= .0032).

Conclusions

Children who were born premature have a higher rate of postoperative aspiration following supraglottoplasty; however, supraglottoplasty should still be considered as treatment for laryngomalacia as the rate is still relatively low (5.9%).

Level of Evidence

2b.Laryngoscope, 124:777–780, 2014
Photovoltaics literature survey (No. 107)
Authors: Shrestha Santosh
Published: December 2013

In order to help keep readers up to date in the field, each issue of Progress in Photovoltaics will contain a list of recently published journal articles most relevant to its aims and scope. This list is drawn from an extremely wide range of journals, including IEEE Transactions on Electron Devices, Journal of Applied Physics, Applied Physics Letters, Progress in Photovoltaics and Solar Energy Materials and Solar Cells. To assist the reader, the list is separated into broad categories, but please note that these classifications are by no means strict. Also note that inclusion in the list is not an endorsement of a paper's quality. If you have any suggestions, please email Santosh Shrestha at s.shrestha@unsw.edu.au.
Differential analysis of transient increases of serum cTnI in response to handling in rats
Authors: Mikaelian Igor , Dunn Michael E. , Mould Diane R. , Hirkaler Gerard , Geng Wanping , Coluccio Denise , Nicklaus Rosemary , Singer Thomas , Reddy Micaela
Published: December 2013

Serum cardiac troponins are the key biomarkers of myocardial necrosis in humans and in preclinical species. The use of ultrasensitive assays for serum cardiac troponin I (cTnI) as a biomarker in safety studies is hampered by interindividual differences. In this study, we investigated the effect of handling procedures on serum cTnI and explored modeling and simulation approaches to mitigate the impact of these interindividual differences. Femoral‐catheterized male Crl:WI(Han) rats (n = 16/group) were left undisturbed in their cages with no handling; subjected to 5 min of isoflurane/O2 anesthesia (A); or placed into a rodent restrainer followed by simulated tail vein injection (RR). Serum cTnI concentrations were assessed over a 24‐h period using an ultrasensitive assay, and the study was repeated for confirmation. The mean serum cTnI concentration pre‐procedure was 4.2 pg/mL, and remained stable throughout the duration of the study in the rats submitted to the A procedure. Serum cTnI concentrations increased transiently after the RR procedure with a median time to maximum concentration (Tmax), of 1 and 2 h and a mean maximum value concentration (Cmax), of 53.0 and 7.2 pg/mL in the initial and repeat studies, respectively. A population pharmacodynamic model identified interindividual, procedure‐ and study‐specific effects on serum cTnI concentrations in rats. It is concluded that a modeling and simulation approach more appropriately describes and statistically analyzes the data obtained with this ultrasensitive assays.
Probing Lipid Coating Dynamics of Quantum Dot Core Micelles via Förster Resonance Energy Transfer
Authors: Zhao Yiming , Schapotschnikow Philipp , Skajaa Torjus , Vlugt Thijs J. H. , Mulder Willem J. M. , de Mello Donegá Celso , Meijerink Andries
Published: December 2013

Lipid coated nanocrystal assemblies are among the most extensively investigated nanoparticle platforms for biomedical imaging and therapeutic purposes. However, very few efforts have been addressed to the lipid coating exchange dynamics in such systems, which is key to our understanding of the nanoparticles' coating stability and their interactions with the environment. Here, we apply the Förster resonance energy transfer (FRET) from quantum dot (QD) core to Cy5.5 dye labeled lipids at the surface to monitor the lipid exchange dynamics in situ and to study its dependence on concentration, temperature and solvent. A kinetic model is developed to describe the experimental data, allowing the rate constants and the activation energy for lipid exchange to be determined. The activation energy for lipid exchange on QD micelles is 155 kJ/mol in saline environment and 130 kJ/mol in pure water. The findings presented here provide basic knowledge on these self‐assembled structures and contribute to understanding their performance and to further design of nanomedicine.
Extended Nanofluidic Immunochemical Reaction with Femtoliter Sample Volumes
Authors: Shirai Kentaro , Mawatari Kazuma , Kitamori Takehiko
Published: December 2013

The growing need to optimize immunoassay performance driven by interest in analyzing individual cells has resulted in a decrease in the amount of sample required. Miniaturized immunoassays that use ultra‐small femtoliter to attoliter sample volumes, a range known as the extended nanospace, can satisfy this analytical need; however, capturing every targeted molecule without loss in extended nanochannels for subsequent detection remains challenging. This is the first report of a successful extended nanofluidics‐based quantitative immunochemical reaction capable of high capture efficiency using a femtoliter‐scale sample volume. A novel patterning method using a photolithographic technique with vacuum ultraviolet light and low‐temperature (100 °C) bonding enables patterning of functional groups for antibody immobilization before bonding, resulting in an immunochemical reaction space of only 86 fL. Reaction rate analyses indicate a decrease in the required sample volume to 810 fL and improvement in the limit of detection to 3 zmol, 5‐6 orders of magnitude better than possible with the microfluidic immunoassay format. Highly efficient (near 100%) immunochemical reactions on a seconds time scale are possible due to the nm‐scale diffusion length, which should be advantageous for the analysis of ultra‐low‐volume samples.
Synthesis, Double‐Helix Formation, and Higher‐Assembly Formation of Chiral Polycyclic Aromatic Compounds: Conceptual Development of Polyketide Aldol Synthesis
Authors: Yamaguchi Masahiko , Shigeno Masanori , Saito Nozomi , Yamamoto Koji
Published: December 2013

Polycyclic aromatic compounds are an important group of substances in chemistry, and the study of their properties is a subject of interest in the development of drugs and materials. We have been conducting studies to develop chiral polycyclic aromatic compounds, i.e., helicenes and equatorenes. These helical molecules showed notable aggregate‐forming properties and the capability for chiral recognition exerted by noncovalent bond interactions, which were not observed in compounds with central chirality. Homo‐ and hetero‐double‐helix‐forming helicene oligomers were developed, and the latter self‐assembled to form gels and vesicles. In this article, we describe such hierarchical studies of polycyclic aromatic compounds, which were started from polyketide aldol synthesis.
Battle against RNA oxidation: molecular mechanisms for reducing oxidized RNA to protect cells
Authors: Li Zhongwei , Malla Sulochan , Shin Brian , Li James M.
Published: December 2013

Oxidation is probably the most common type of damage that occurs in cellular RNA. Oxidized RNA may be dysfunctional and is implicated in the pathogenesis of age‐related human diseases. Cellular mechanisms controlling oxidized RNA have begun to be revealed. Currently, a number of ribonucleases and RNA‐binding proteins have been shown to reduce oxidized RNA and to protect cells under oxidative stress. Although information about how these factors work is still very limited, we suggest several mechanisms that can be used to minimize oxidized RNA in various organisms.

This article is categorized under:

RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms

RNA in Disease and Development > RNA in Disease
Nisin production in a chitin-including continuous fermentation system with Lactococcus lactis displaying a cell wall chitin-binding domain
Authors: Şimşek Ömer
Published: December 2013

The limiting factors in the continuous production of nisin are high amount of biomass loss and low dilution rate application. In this study, a chitin-including continuous nisin fermentation system (CICON-FER) was constructed for high volumetric nisin production using nisin producer L. lactis displaying cell wall chitin-binding domain (ChBD) together with chitin in the reactor. In this respect, the highest binding conditions of relevant L. lactis cells to chitin were determined. Then the chitin flakes carrying nisin-producing L. lactis cells were used within the CICON-FER system at different dilution rates (0.1–0.9 h−1) and initial glucose concentrations (20–60 g l−1). The results revealed that the pH 7 conditions and the use of 100 mM sodium phosphate buffer with 0.1 % Tween 20 and Triton X-100 significantly increased the binding capacity of ChBD displaying L. lactis cells to chitin. The constructed CICON-FER system maintained the presence of the ChBD surface displaying L. lactis cells in the reactor system until 0.9 h−1 dilution rate that resulted in a considerably high level of volumetric nisin production and productivity (10,500 IU ml−1 and 9,450 IU ml−1 h−1, respectively) with the combination of a 0.9-h−1 dilution rate and a 40-g l−1 initial glucose concentration. In conclusion, an innovative nisin fermentation system that yielded the highest nisin production thus far and that was feasible for industrial application was created.
Mukoviszidose – eine pleiotrope Ionenkanalerkrankung mit wesentlicher Lungenbeteiligung
Authors: Stanke F. , Tümmler B. , Stuhrmann M.
Published: December 2013

Die monogene Erkrankung Mukoviszidose wird durch Mutationen im Cystic-fibrosis-transmembrane-conductance-regulator(CFTR)–Gen verursacht und folgt einem rezessiven Erbgang. Die erfolgreiche Diagnose der Erkrankung erfolgt durch eine enge Verzahnung von klinischer Beurteilung, humangenetischer Diagnostik und patientennaher Analyse des CFTR-vermittelten Basisdefekts durch Nachweis von dysfunktionalem CFTR in der Schweißdrüse, der Nasen- oder der Darmschleimhaut. Häufig ist eine Differenzialdiagnose zu CFTR-abhängigen Erkrankungen wie kongenitaler bilateraler Aplasie der Vasa deferentia (CBAVD), Pankreatitis und Bronchiektasen nötig. Für einige CFTR-Mutationen stehen spezifische Therapeutika zur Verfügung, die auf die jeweilige Sequenzvariante zugeschnitten sind und so den CFTR-Mutationsgenotyp direkt klinisch nutzbar machen.
Perspectives: a journal on the cutting edge of educational research and development. Introduction from the new Editor in Chief
Authors: Driessen Erik
Published: December 2013

None
On the weak solutions to the equations of a compressible heat conducting gas
Authors: Chiodaroli Elisabetta , Feireisl Eduard , Kreml Ondřej
Published: December 2013

We consider the weak solutions to the Euler–Fourier system describing the motion of a compressible heat conducting gas. Employing the method of convex integration, we show that the problem admits infinitely many global-in-time weak solutions for any choice of smooth initial data. We also show that for any initial distribution of the density and temperature, there exists an initial velocity such that the associated initial-value problem possesses infinitely many solutions that conserve the total energy.
Cyclic cohomology and Baaj-Skandalis duality
Authors: Voigt Christian
Published: December 2013

We construct a duality isomorphism in equivariant periodic cyclic homology analogous to Baaj-Skandalis duality in equivariant Kasparov theory. As a consequence we obtain general versions of the Green-Julg theorem and the dual Green-Julg theorem in periodic cyclic theory.

Throughout we work within the framework of bornological quantum groups, thus in particular incorporating at the same time actions of arbitrary classical Lie groups as well as actions of compact or discrete quantum groups. An important ingredient in the construction of our duality isomorphism is the notion of a modular pair for a bornological quantum group, closely related to the concept introduced by Connes and Moscovici in their work on cyclic cohomology for Hopf algebras.