bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulations of the latitudinal variability of CO‐like and OCS‐like passive tracers below the clouds of Venus using the Laboratoire de Météorologie Dynamique GCM
Authors: Marcq E. , Lebonnois S.
Published: October 2013

The lower atmosphere of Venus below the clouds is a transitional region between the relatively calm lowermost scale height and the superrotating atmosphere in the cloud region and above. Any observational constraint is then welcome to help in the development of general circulation models of Venus, a difficult task considering the thickness of its atmosphere. Starting from a state‐of‐the‐art 3‐D Venus General Circulation Model (GCM), we have included passive tracers in order to investigate the latitudinal variability of two minor gaseous species, carbonyl sulfide (OCS) and carbon monoxide (CO), whose vertical profiles and mixing ratios are known to vary with latitude between 30 and 40km. The relaxation to chemical equilibrium is crudely parametrized through a vertically uniform time scale τ. A satisfactory agreement with available observations is obtained with 108s≲τCO≲5·108 s and 107s≲τOCS≲108 s. These results, in addition to validating the general circulation below the clouds, are also helpful in characterizing the chemical kinetics of Venus' atmosphere. This complements the much more sophisticated chemical models which focus more on thermodynamical equilibrium.
Uncertainties in the shock devolatilization of hydrated minerals: A nontronite case study
Authors: Kraus R. G. , Stewart S. T. , Newman M. G. , Milliken R. E. , Tosca N. J.
Published: October 2013

Controlled recovery of hydrated minerals subjected to planar shock loading is challenging because of the large difference in shock impedance between the natural samples and the engineering materials used as the recovery capsules. Significant differences in recovery capsule design confound straightforward interpretation of existing data on shock modification of hydrated minerals. We present X‐ray diffraction and infrared spectroscopy results from new shock recovery experiments on nontronite (a smectite clay observed on Mars) and identify major issues in the interpretation of recovered samples. Previous work assumes that the first shock pressure step in a ring‐up configuration is the most important factor in the interpretation of shock modification. By comparing the X‐ray diffraction and infrared spectroscopy data from experiments with similar first shock steps but significantly different final shock states, we show that one cannot simply interpret the recovered samples based upon the first shock pressure step. This work demonstrates the need for a deeper understanding of the thermodynamics of ring‐up experiments in order to be able to interpret the results in terms of an equivalent single shock loading pressure for planetary applications. In this work, we also show that venting of the samples does not matter significantly at low pressures but may be important at high pressures. We have developed a recovery method and validation test that allows us to address the major issues and technical tradeoffs with shock recovery experiments on volatile materials.
Formation of biogenic sheath‐like Fe oxyhydroxides in a near‐neutral pH hot spring: Implications for the origin of microfossils in high‐temperature, Fe‐rich environments
Authors: Peng Xiaotong , Chen Shun , Xu Hengchao
Published: October 2013

A small hot spring that is informally called “Fe‐waterfall spring” and is located in the Rehai geothermal area discharges hot (42 to 73°C), near‐neutral (pH = 7.65) Fe‐rich water. Submerged reddish precipitates are composed largely of ferrihydrite, goethite, lepidocrocite, opal‐A, quartz, and anorthite, as revealed by X‐ray diffraction (XRD) and Mössbauer spectroscopy. Molecular phylogenetic analysis demonstrates that the bacterial community in these precipitates is mainly composed of Cyanobacteria, Planctomycetes, β‐proteobacteria, Deinococci‐Thermus, and Chlorobi. Scanning electron microscopy and high‐resolution transmission electron microscopy examinations show that abundant sheath‐like Fe oxyhydroxides, which exhibit different morphologies and sizes, are present in Fe‐rich precipitates. These sheath‐like structures are composed of ferrihydrite rather than more crystalline lepidocrocite or goethite. Energy‐dispersive X‐ray spectrometer, scanning transmission electron microscopy, and nano secondary ion mass spectrometry reveal that they are mainly composed of Fe, Si, and O, together with some trace elements. Most of the sheath‐like structures are not morphologically comparable to biogenic Fe oxyhydroxides produced by known chemolithotrophic Fe oxidizers, which is consistent with the fact that no chemolithotrophic Fe oxidizers were identified by molecular analysis in the precipitates. We suggest that the sheath‐like Fe oxyhydroxides are formed through passive Fe sorption and nucleation onto the cell walls of various thermophiles rather than by the direct metabolic activities of chemolithotrophic Fe oxidizers. Biogenic sheath‐like Fe oxyhydroxides in Fe‐waterfall spring have important implications for geochemical cycles driven by microorganisms, the origin of microfossils, and the formation of banded iron formations (BIFs) in the Archean ocean.
Risk of redocumenting penicillin allergy in a cohort of patients with negative penicillin skin tests
Authors: Rimawi Ramzy H. , Shah Kaushal B. , Cook Paul P.
Published: October 2013

BACKGROUND

Even though electronic documentation of allergies is critical to patient safety, inaccuracies in documentation can potentiate serious problems. Prior studies have not evaluated factors associated with redocumenting penicillin allergy in the medical record despite a proven tolerance with a penicillin skin test (PST).

OBJECTIVE

Assess the prevalence of reinstating inaccurate allergy information and associated factors thereof.

DESIGN

We conducted a retrospective observational study from August 1, 2012 to July 31, 2013 of patients who previously had a negative PST. We reviewed records from the hospital, long‐term care facilities (LTCF), and primary doctors' offices.

SETTING

Vidant Health, a system of 10 hospitals in North Carolina.

SUBJECTS

Patients with proven penicillin tolerance rehospitalized within a year period from the PST.

MEASUREMENTS

We gauged hospital reappearances, penicillin allergy redocumentation, residence, antimicrobial use, and presence of dementia or altered mentation.

RESULTS

Of the 150 patients with negative PST, 55 (37%) revisited a Vidant system hospital within a 1‐year period, of whom 21 were LTCF residents. Twenty (36%) of the 55 patients had penicillin allergy redocumented without apparent reason. Factors associated with penicillin allergy redocumentation included age >65 years (P = 0.011), LTCF residence (P = 0.0001), acutely altered mentation (P < 0.0001), and dementia (P < 0.0001). Penicillin allergy was still listed in all 21 (100%) of the LTCF records.

CONCLUSIONS

At our hospital system, penicillin allergies are often redocumented into the medical record despite proven tolerance. The benefits of PST may be limited by inadequately removing the allergy from different electronic/paper hospital, LTCF, primary physician, and community pharmacy records. Journal of Hospital Medicine 2013;8:615–618. © 2013 Society of Hospital Medicine
Usefulness of the SPACE pulse sequence at 1.5T MR cholangiography: Comparison of image quality and image acquisition time with conventional 3D‐TSE sequence
Authors: Nakaura Takeshi , Kidoh Masafumi , Maruyama Natsuki , Kawahara Tetsuya , Namimoto Tomohiro , Sakai Yoshinari , Harada Kazunori , Yamashita Yasuyuki
Published: October 2013

Purpose

To prospectively evaluate the image quality and image acquisition time at 3D magnetic resonance cholangiopancreatography (MRCP) using sampling perfection with application optimized contrasts (SPACE) and conventional turbo‐spin‐echo (TSE) sequences.

Materials and Methods

We acquired navigator‐triggered SPACE and conventional 3D‐TSE MRCP images using the same parameters where possible for 30 patients and compared the image acquisition time, contrast, and contrast‐to‐noise ratio (CNR) of the common bile duct (CBD). Two radiologists performed qualitative analyses using a 4‐point scale.

Results

Image acquisition time was 31% shorter with the SPACE than the conventional TSE sequence (248.9 ± 73.0 sec vs. 360.5 ± 99.9 sec, P < 0.01). The contrast and CNR was significantly higher with the SPACE technique than conventional TSE (39.4 ± 14.7 vs. 33.5 ± 14.2, P < 0.01 and 18.6 ± 7.8 vs. 15.5 ± 9.3, P = 0.03). All visual scores were higher for the SPACE than the conventional TSE sequence; there was a significant difference in motion artifacts and the depiction of the CBD and the left hepatic and main pancreatic duct (P < 0.05).

Conclusion

On the 1.5T MR scanner, 3D‐MRCP with the SPACE sequence significantly improved the contrast and CNR of CBD. In addition, it yielded images of better quality at 30% shorter acquisition time than constant refocusing pulse flip angle TSE. J. Magn. Reson. Imaging 2013;38:1014–1019. © 2013 Wiley Periodicals, Inc.
The E693Δ (Osaka) mutation in amyloid precursor protein potentiates cholesterol‐mediated intracellular amyloid β toxicity via its impaired cholesterol efflux
Authors: Nomura Sachiko , Umeda Tomohiro , Tomiyama Takami , Mori Hiroshi
Published: October 2013

It has been shown that amyloid β (Aβ) secretion regulates cholesterol efflux from cells and that the E693Δ (Osaka) mutation in amyloid precursor protein (APP) promotes intracellular accumulation of Aβ and thus reduces its secretion. These findings led us to speculate that APP with the Osaka mutation (APPOSK) might have a defect in cholesterol efflux and thus cause cellular malfunction. We therefore examined the effects of this mutation on intracellular cholesterol transport and efflux in cultured cells. Upon cholesterol loading, APPOSK‐expressing cells exhibited higher levels of cellular cholesterol than wild‐type APP‐expressing cells, suggesting impaired cholesterol efflux. It is known that, after its internalization, cholesterol is transported from the endosomes to the endoplasmic reticulum (ER) and Golgi apparatus and then to the plasma membrane. In APPOSK‐expressing cells, cholesterol accumulated with Aβ in the ER and Golgi apparatus and alone in endosomes/lysosomes. These results imply that the mutation‐induced disturbance of Aβ trafficking from the ER to the plasma membrane affects cholesterol transport to cause cholesterol accumulation in the ER and Golgi apparatus and, consequently, in endosomes. Furthermore, we detected an enhanced mitochondrial accumulation of Aβ and cholesterol in APPOSK‐expressing cells, and this was accompanied by an increase in the generation of reactive oxygen species (ROS). The present findings suggest that Aβ trafficking is important for intracellular cholesterol transport and efflux and that the Osaka mutation potentiates cholesterol‐dependent exacerbation of intracellular Aβ toxicity, i.e. Aβ‐induced ROS generation, by disturbing Aβ‐mediated cholesterol efflux from the cell. © 2013 Wiley Periodicals, Inc.
Effects of adjustment for non‐climatic discontinuities on determination of temperature trends and variability over Iran
Authors: Rahimzadeh Fatemeh , Nassaji Zavareh Mojtaba
Published: October 2013

In‐situ observations of surface air temperature at 55 weather stations in Iran are analysed for homogeneity and trends over the period 1960–2010. Among them 32 stations have data available for the whole period. The other 23 stations with shorter records are used only to confirm variability during overlapping periods. Discontinuities in the temperature series relate mostly to relocation and changes of environmental conditions at individual stations. These changes alter the statistical characteristics of temperature, including the mean, variance, and frequency distribution and introduce uncertainties in spatially averaged trends. This article determines new estimates of temperature trends over Iran after the detection of artificial change points and application of homogenization.

The regional trend of temperature is estimated using seasonal and annual minimum and maximum temperature from stations that have identical variability across the country. The country may be segmented to 10 such regions in terms of trends and variability of temperature. There is little doubt that temperatures have increased in all regions at nearly equal rates of 0.4–0.5 and 0.2–0.3 (°C/decade) for minimum and maximum temperature, respectively in Iran. The finding in earlier work of a few individual stations with negative trends is found to be due to artificial effects such as relocation.
Linear quantification calibration of crystallinity based on a simple univariate analysis of binary chemical images by selecting a threshold to define the sampling depth in Raman mapping
Authors: Wu Jianping
Published: October 2013

It is common belief that in Raman mapping, the sampling depth from which Raman signal is collected originates from a probe laser spot size of approximately 1–5 µm3. Actually, the active pharmaceutical ingredient (API) crystals detected by mapping on the sample surface distribute from surface to over a few tens to hundreds of microns into the sample, as determined by z‐slices mapping in this context. It was also found that the score of API crystals detected in a chemical image decrease with their depth into the sample. Therefore, a larger threshold of the binary chemical images can be used to restrict the sampling depth and consequently eliminate the problem of ‘saturation’ by quantifying merely the amount of API crystals within a sampling volume equivalent to a smaller sampling depth rather than the overall detected crystalline API in the chemical images. Eventually, one single linear quantification calibration was established over the crystallinity from sub‐percent (<1%) to over 20% w/w of a model sample by using a simple univariate analysis of binary chemical images method. Copyright © 2013 John Wiley & Sons, Ltd.
Solution‐based SERS method to detect dithiocarbamate fungicides in different real‐world matrices
Authors: Saute Benjamin , Narayanan Radha
Published: October 2013

Surface‐enhanced Raman scattering (SERS) has become a valuable tool for the characterization of trace quantities of environmental toxins. Utilizing established wet chemical synthetic protocols, dogbone‐shaped colloidal gold nanoparticle substrates with sharp features were prepared with regions that exhibit significant SERS enhancement due to the lightning rod effect. These highly enhancing substrates were utilized for the quantitative determination of two dithiocarbamate fungicides by SERS in several complex matrices such as tap water, apple juice, and vegetable juice. Limits of detection and quantitation are reported and compared with Environmental Protection Agency mandated maximum allowable concentrations in tap water. In the case of tap water, limits of detection of 13.39 ± 3.89 nM for thiram and 1.78 ± 0.20 nM for ferbam was achieved. The sensitivity of the solution‐based SERS method decreased with increasing complexity of the matrix in which the limit of detection achieved in apple juice is 47.22 nM for thiram and 11.88 ± 1.38 nM for ferbam and that for vegetable juice is 87.01 ± 2.88 nM for thiram and 36.72 ± 2.90 nM for ferbam. It was found that using the solution‐based SERS method results in sensitivities that are greater than that required by Environmental Protection Agency mandated maximum allowable concentrations for complex matrices such as apple and vegetable juice. Copyright © 2013 John Wiley & Sons, Ltd.
Cow's milk with active immunoglobulins againstCampylobacter jejuni: Effects of temperature on immunoglobulin activity
Authors: Riera Francisco , Alvarez Alejandro , Espi Alberto , Prieto Miguel , de la Roza Begoña , Vicente Fernando
Published: October 2013

BACKGROUND

Adult Holstein cows were injected with an antiserum againstCampylobacter jejuniand immunoglobulin activitiesin vitrowere determined in blood and milk several weeks after injection. The immunoactivity of immunoglobulins in milk was measured by an ELISA after different temperature–time treatments (60–91°C and 4–3600 s) at laboratory and pilot‐plant scales. Kinetic and thermodynamic parameters were determined.

RESULTS

An increase in immunoglobulin activity in milk was detected several days after injection. Optical densities increased by three‐ to seven‐fold in this period. The activity started to decay 4–5 weeks after injection. Immunoglobulins maintained most of theirin vitroactivity under pasteurisation conditions (72°C and 15 s) and were denatured following first‐order kinetics.

CONCLUSIONS

The injection protocol applied allows milk with specific immunoglobulins againstCampylobacter jejunito be obtained. Traditional pasteurisation did not reduce this activity. © 2013 Society of Chemical Industry
Evaluation of Camelina sativa (L.) Crantz meal as an alternative protein source in ruminant rations
Authors: Colombini Stefania , Broderick Glen A , Galasso Incoronata , Martinelli Tommaso , Rapetti Luca , Russo Roberto , Reggiani Remo
Published: October 2013

BACKGROUND

Camelina sativa (CS) is an oilseed crop used for biofuel production. By‐products from oil extraction are high in protein and can be used in ruminant rations; more information about their nutritive value is required also considering the antinutrional factor content of the by‐products. The aim of this study was to evaluate the nutritive value of CS meal genotypes in comparison with canola.

RESULTS

Ten CS genotypes and one canola cultivar were evaluated. Meals were obtained from seeds after solvent oil extraction. CS average crude protein (CP) content (g kg−1 dry matter) was 457. Numerical differences in lysine and sulfur amino acid content were observed among CS genotypes. Glucosinolate (mmol kg−1) content was higher for CS (23.1) than canola (7.2). Sinapine content (g kg−1) was lower for CS (2.79) than for canola (4.32). Differences were observed among CS genotypes for rumen undegraded protein (RUP). Average RUP (g kg−1 CP) was 316 for CS and 275 for canola.

CONCLUSIONS

CS meal has potential for use in ruminant rations as a high‐quality protein source. In vivo studies are needed to compare CS with other protein sources used in cattle rations. Implementation of breeding programs for improved meal quality is recommend. © 2013 Society of Chemical Industry
HPLC analysis of synthetic polymers on short monolithic columns
Authors: Maksimova Elena , Vlakh Evgenia , Sinitsyna Ekaterina , Tennikova Tatiana
Published: October 2013

Ultrashort monolithic columns (disks) were thoroughly studied as efficient stationary phases for precipitation–dissolution chromatography of synthetic polymers. Gradient elution mode was applied in all chromatographic runs. The mixtures of different flexible chain homopolymers, such as polystyrenes, poly(methyl methacrylates), and poly(tert‐butylmethacrylates) were separated according to their molecular weights on both commercial poly(styrene‐co‐divinylbenzene) disks (12 id × 3 mm and 5 × 5 mm) and lab‐made monolithic columns (4.6 id × 50 mm) filled with supports of different hydrophobicity. The experimental conditions were optimized to reach fast and highly efficient separation. It was observed that, similar to the separation of monoliths of other classes of (macro)molecules (proteins, DNA, oligonucleotides), the length of column did not affect the peak resolution. A comparison of the retention properties of the poly(styrene‐co‐divinylbenzene) disk‐shaped monoliths with those based on poly(lauryl methacrylate‐co‐ethylene dimethacrylate), poly(butyl methacrylate‐co‐ethylene dimethacrylate), and poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) supports demonstrated the obvious effect of surface chemistry on the resolution factor. Additionally, the results of the discussed chromatographic mode on the fast determination of the molecular weights of homopolymers used in this study were compared to those established by SEC on columns packed with sorbent beads of a similar nature to the monoliths.
Airway algorithm for the management of patients with a king LT
Authors: Khaja Sobia F. , Chang Kristi E.
Published: October 2013

Objectives/Hypothesis

To discuss an algorithm for managing the airway in patients presenting with a King LT in place.

Study Design

Case series at a single institution with planned chart review.

Methods

This study reviewed the management of three patients who presented to a tertiary academic medical facility emergency department following placement of a King LT at an outside hospital or in the field. Clinical history at admission as well as each patient's hospital course was evaluated. We discuss the management of the airway in each of these cases and use these to help design an algorithm for improving outcomes in patients with a King LT in place.

Results

In each of the three cases presented, the Otolaryngology Department was consulted for definitive airway management. In two of these patients, the airway was successfully secured using endotracheal intubation. Only one patient required tracheostomy. We discuss an algorithm for managing these patients to obtain a safe airway, which includes assessing the airway with flexible endoscopy and then proceeding with intubation by the Seldinger technique or intubation using a video laryngoscope. In some cases, tracheostomy will be required to definitively secure the airway.

Conclusions

The King LT is a valuable tool available in the field to help to temporarily secure the airway. Otolaryngologists should have an appropriate airway algorithm for managing patients with a King LT in place to minimize the need for a tracheostomy.

Level of Evidence

4. Laryngoscope, 124:1123–1127, 2014
Otolaryngology and medical malpractice: A review of the past decade, 2001–2011
Authors: Hong Steven S. , Yheulon Christopher G. , Wirtz Eric D. , Sniezek Joseph C.
Published: October 2013

Objectives/Hypothesis

To better understand the causes and outcomes of lawsuits involving otolaryngologists in the past decade by analyzing malpractice litigation trends to prevent future litigation and improve physician education.

Study Design

Analysis of a national database for all US civil trials.

Methods

The Westlaw database was reviewed from 2001 to 2011. Data were compiled on the demographics of the plaintiffs, use of expert witnesses, procedures, nature of the injury, legal allegations, verdicts, and indemnities.

Results

One hundred ninety‐eight cases met inclusion criteria. Verdicts for the defendant/otolaryngologist predominated (58%), whereas the average award when the verdict favored the plaintiff was $1,782,514. When otolaryngologists were used as expert witnesses by the defense, the verdict outcome statistically favored the defendant. Two of the most commonly cited legal allegations were improper performance and failure to diagnose and treat. Fifty‐one cases involved allegations of wrongful death, with the overall outcome favoring the plaintiffs (51%). The average indemnities in these cases were significantly higher for plaintiff verdicts at $2,552,580 versus settlements at $992,896. Forty‐two cases involved malignancy, with the two most common allegations being failure to diagnose and treat (79%) and delay in diagnosis (74%).

Conclusions

Our study reveals that in the past decade, in significant malpractice litigations, overall outcomes favored otolaryngologists. The average awards was significantly higher when cases involved malignancy. Our analysis reveals the importance of meticulous surgical techniques and thorough preoperative evaluations. Last, when otolaryngologists are defendants in litigation, our review reiterates the value of the otolaryngologist as the defense's expert witnesses. Laryngoscope, 124:896–901, 2014
Micro‐LED pumped polymer laser: A discussion of future pump sources for organic lasers
Authors: Herrnsdorf Johannes , Wang Yue , McKendry Jonathan J. D. , Gong Zheng , Massoubre David , Guilhabert Benoit , Tsiminis Georgios , Turnbull Graham A. , Samuel Ifor D. W. , Laurand Nicolas , Gu Erdan , Dawson Martin D.
Published: October 2013

Optical pumping conditions for organic solid‐state lasers (OSLs) are discussed with particular emphasis on the use of gallium nitride based light‐emitting diodes (LEDs) as pump sources. LEDs operate in a regime where the pump should be optimized for a short rise time and high peak intensity, whereas fall time and overall pulse duration are less important. Lasers pumped with this approach need to have very low thresholds which can now be routinely created using (one‐dimensional) distributed feedback lasers. In this particular case stripe‐shaped excitation with linearly polarized light is beneficial. Arrays of micron‐sized flip‐chip LEDs have been arranged in an appropriate stripe shape and the array dimensions were chosen such that the divergence of LED emission does not cause a loss in peak intensity. These micro‐LED arrays have successfully been used to pump OSLs with thresholds near 300 W/cm2 (∼9 ns rise time, 35 ns pulse duration), paving the way for compact arrays of indirectly electrically pumped OSLs.
Efficacy of Crosslinking on Tailoring In Vivo Biodegradability of Fibro‐Porous Decellularized Extracellular Matrix and Restoration of Native Tissue Structure: A Quantitative Study using Stereology Methods
Authors: Burugapalli Krishna , Chan Jeffrey C. Y. , Kelly John L. , Pandit Abhay S.
Published: October 2013

Cholecyst‐derived extracellular matrix (CEM) is a fibro‐porous decellularized serosal layer of porcine gall‐bladder. CEM loses 90% of its weight at 48 h of in vitro collagenase digestion, but takes two months to be completely resorbed in vivo. Carbodiimide (EDC) crosslinking helps tailoring CEM's in vitro collagenase susceptibility. Here, the efficacy of EDC crosslinking on tailoring in vivo biodegradability of CEM is reported. CEM crosslinked with 0.0005 and 0.0033 × 103 M of EDC/mg that lose 80% and 0% of their weight respectively to in vitro collagenase digestion, were present even after 180 days in vivo. Quantitative histopathology using stereology methods confirmed our qualitative observation that even a tiny degree of crosslinking can significantly prolong the rate of in vivo degradation and removal of CEM.
Enhanced Stem Cell Pluripotency in Surface‐Modified Electrospun Fibrous Matrices
Authors: Zonca Michael R. , Yune Philip S. , Williams James K. , Gu Minghao , Unser Andrea M. , Imbrogno Joseph , Belfort Georges , Xie Yubing
Published: October 2013

A previously screened “hit chemistry” (N‐[3‐(dimethylamino)propyl] methacrylamide) that supports strong attachment and long‐term self‐renewal of ES cells is selected and grafted to poly(ether sulfone) (PES) fibrous matrices through plasma‐induced graft polymerization. The 3D modified fibers exhibit higher cell proliferation and greater expression of pluripotency markers of mouse ES cells than 2D membranes. It is the first demonstration of scaling up an optimal synthetic surface chemistry in 2D using a high throughput synthesis, screening, and selection method to 3D that strongly influences pluripotent stem cell growth.
Small Interfering RNA Nunchucks with a Hydrophobic Linker for Efficient Intracellular Delivery
Authors: Jo Sung Duk , Kim Jee Seon , Joe Cheol O. , Mok Hyejung , Nam Yoon Sung
Published: October 2013

The high stiffness and low spatial charge density of siRNA limit the effectiveness of the electrostatic condensation of siRNA with cationic polyelectrolytes. Here, a facile method to stabilize nanoscale siRNA/polyelectrolyte complexes by introducing a reductively cleavable alkyl chain to siRNA as a hybrophobic linker of dimeric siRNA conjugates is reported. The increased length of the hydrophobic linker increases the intracellular translocation and gene silencing activity of the dimeric siRNA conjugates when they are complexed with linear polyethylenimine (LPEI). The results suggest that the introduction of a hydrophobic linker in the dimeric siRNA conjugates can facilitate the intracellular delivery of siRNA through effective condensation with cationic polyelectrolytes.
Private Equity and the Innovation Strategies of Entrepreneurial Firms: Empirical Evidence from the Small Business Innovation Research Program
Authors: Link Albert N. , Ruhm Christopher J. , Siegel Donald S.
Published: October 2013

There is great interest in evaluating the impact of private equity investments on innovation and economic growth. However, there is no direct empirical evidence on the effects of such transactions on the innovation strategies of entrepreneurial firms. We fill this gap by examining a rich project‐level data set consisting of entrepreneurial firms receiving Small Business Innovation Research (SBIR) program research awards. We find that SBIR firms attracting private equity investments are significantly more likely to license and sell their technology rights and engage in collaborative research and development agreements. Our results suggest that private equity investments accelerate the development and commercialization of research‐based technologies, thus contributing to economic growth. We conclude that both public and private investments have a positive effect on innovation performance. Copyright © 2013 John Wiley & Sons, Ltd.
Next‐generation DNA sequencing of HEXA: a step in the right direction for carrier screening
Authors: Hoffman Jodi D. , Greger Valerie , Strovel Erin T. , Blitzer Miriam G. , Umbarger Mark A. , Kennedy Caleb , Bishop Brian , Saunders Patrick , Porreca Gregory J. , Schienda Jaclyn , Davie Jocelyn , Hallam Stephanie , Towne Charles
Published: October 2013

Tay‐Sachs disease (TSD) is the prototype for ethnic‐based carrier screening, with a carrier rate of ~1/27 in Ashkenazi Jews and French Canadians. HexA enzyme analysis is the current gold standard for TSD carrier screening (detection rate ~98%), but has technical limitations. We compared DNA analysis by next‐generation DNA sequencing (NGS) plus an assay for the 7.6 kb deletion to enzyme analysis for TSD carrier screening using 74 samples collected from participants at a TSD family conference. Fifty‐one of 74 participants had positive enzyme results (46 carriers, five late‐onset Tay‐Sachs [LOTS]), 16 had negative, and seven had inconclusive results. NGS + 7.6 kb del screening of HEXA found a pathogenic mutation, pseudoallele, or variant of unknown significance (VUS) in 100% of the enzyme‐positive or obligate carrier/enzyme‐inconclusive samples. NGS detected the B1 allele in two enzyme‐negative obligate carriers. Our data indicate that NGS can be used as a TSD clinical carrier screening tool. We demonstrate that NGS can be superior in detecting TSD carriers compared to traditional enzyme and genotyping methodologies, which are limited by false‐positive and false‐negative results and ethnically focused, limited mutation panels, respectively, but is not ready for sole use due to lack of information regarding some VUS.
Characterization of Ile‐His‐Arg‐Phe, a novel rice‐derived vasorelaxing peptide with hypotensive and anorexigenic activities
Authors: Kontani Noriyasu , Omae Ryo , Kagebayashi Tomomi , Kaneko Kentaro , Yamada Yuko , Mizushige Takafumi , Kanamoto Ryuhei , Ohinata Kousaku
Published: October 2013

Scope

Recently, we found that dipeptide Arg‐Phe (RF) had cholecystokinin (CCK)‐dependent vasorelaxing activity. The RF sequence is often observed in the primary structure of natural food proteins. In the current study, we investigated enzymatic conditions for the release of RF‐related peptides from rice glutelin, a major storage protein, using gastrointestinal proteases. RF‐related peptides were then characterized.

Methods and results

It was found that RF and Ile‐His‐Arg‐Phe (IHRF) were released in the chymotrypsin digest of the partial structure of rice glutelin. We then focused on previously unidentified IHRF, corresponding to rice glutelin(155−158). IHRF had vasorelaxing activity in the mesenteric artery of spontaneous hypertensive rats (SHRs). Orally administered IHRF lowered systolic blood pressure in SHRs. The antihypertensive activity of IHRF was more potent and long‐lasting than that of RF. IHRF‐induced vasorelaxing activity was not blocked by inhibitors of nitric oxide synthase and cyclooxygenase, but by an antagonist for CCK1 receptor. IHRF also had CCK‐like suppressive activities in food intake and gastrointestinal transit. IHRF increased intracellular Ca2+ flux and CCK release in the enteroendocrine cell STC‐1.

Conclusion

IHRF, a novel CCK‐dependent vasorelaxing peptide, decreases both blood pressure and food intake in rodents.
Defining the neighborhoods that escort the oocyte through its early life events and into a functional follicle
Authors: Jorgensen Joan S.
Published: October 2013

The ovary functions to chaperone the most precious cargo for female individuals, the oocyte, thereby allowing the passage of genetic material to subsequent generations. Within the ovary, single oocytes are surrounded by a legion of granulosa cells inside each follicle. These two cell types depend upon one another to support follicle formation and oocyte survival. The infrastructure and events that work together to ultimately form these functional follicles within the ovary are unprecedented, given that the oocyte originates as a cell like all other neighboring cells within the embryo prior to gastrulation. This review discusses the journey of the germ cell in the context of the developing female mouse embryo, with a focus on specific signaling events and cell–cell interactions that escort the primordial germ cell as it is specified into the germ cell fate, migrates through the hindgut into the gonad, differentiates into an oocyte, and culminates upon formation of the primordial and then primary follicle. Mol. Reprod. Dev. 80: 960–976, 2013. © 2013 Wiley Periodicals, Inc.
Particle Responses to Flow Field Oscillations in Heterogeneous Polymerizations Performed in Tank Reactors
Authors: Poubel Willian M. , Silva Carlos E. F. C. , Souza Evandro N. , Pinto José Carlos
Published: October 2013

This work analyzes the possible influence of the inevitable temperature and concentration fluctuations that take place inside typical stirred tank heterogeneous polymerization reactors on the evolution of kinetic variables. Preliminary analyses regarding the characteristic time constants for heat and mass transfer inside polymer particles that are suspended in a continuous phase are performed in order to evaluate how fast particles respond to perturbations along a dynamic trajectory inside the reactor. It is concluded that particles of typical heterogeneous systems can respond almost immediately to operation changes. For this reason, simulations are performed to evaluate the influence of the varying temperature and concentration fields on the evolution of kinetic variables. It is concluded that the effects caused by the inevitable fluctuations of temperature and concentration inside the vessel can be neglected in usual conditions of reaction of heterogeneous polymerization systems.
Improved susceptibility weighted imaging method using multi‐echo acquisition
Authors: Oh Sung Suk , Oh Se‐Hong , Nam Yoonho , Han Dongyeob , Stafford Randall B. , Hwang Jinyoung , Kim Dong‐Hyun , Park HyunWook , Lee Jongho
Published: October 2013

Purpose

To introduce novel acquisition and postprocessing approaches for susceptibility weighted imaging (SWI) to remove background field inhomogeneity artifacts in both magnitude and phase data.

Methods

The proposed method acquires three echoes in a three‐dimensional gradient echo (GRE) sequence, with a field compensation gradient (z‐shim gradient) applied to the third echo. The artifacts in the magnitude data are compensated by signal estimation from all three echoes. The artifacts in phase signals are removed by modeling the background phase distortions using Gaussians. The method was applied in vivo and compared with conventional SWI.

Results

The method successfully compensates for background field inhomogeneity artifacts in magnitude and phase images, and demonstrated improved SWI images. In particular, vessels in frontal lobe, which were not observed in conventional SWI, were identified in the proposed method.

Conclusion

The new method improves image quality in SWI by restoring signal in the frontal and temporal regions. Magn Reson Med 72:452–458, 2014. © 2013 Wiley Periodicals, Inc.
Spatial encoding using the nonlinear field perturbations from magnetic materials
Authors: Karimi Hirad , Dominguez‐Viqueira William , Cunningham Charles H.
Published: October 2013

Purpose

A proof‐of‐concept study was performed to assess the technical feasibility of using magnetic materials to generate spatial encoding fields.

Theory and Methods

Spatially varying magnetic fields were generated by the placement of markers with different volume susceptibilities within the imaging volume. No linear gradients were used for spatial encoding during the signal acquisition. A signal‐encoding model is described for reconstructing the images encoded with these field perturbations. Simulation and proof‐of‐concept experimental results are presented. Experiments were performed using field perturbations from a cylindrical marker as an example of the new encoding fields. Based on this experimental setup, annular rings were reconstructed from signals encoded with the new fields.

Results

Simulation results were presented for different acquisition parameters. Proof‐of‐concept was supported by the correspondence of regions in an image reconstructed from experimental data compared to those in a conventional gradient‐echo image. Experimental results showed that inclusions of dimensions 1.5 mm in size could be resolved with the experimental setup.

Conclusion

This study shows the technical feasibility of using magnetic markers to produce encoding fields. Magnetic materials will allow generating spatial encoding fields, which can be tailored to an imaging application with less complexity and at lower cost compared to the use of gradient inserts. Magn Reson Med 72:399–408, 2014. © 2013 Wiley Periodicals, Inc.
Dynamic response to fluid extraction from a poroelastic half‐space
Authors: Zheng Pei , Ding Boyang , Zhang Weigang , Zhao She‐Xu , Zhu Yijun
Published: October 2013

In this study, the dynamic response of a poroelastic half‐space to a point fluid sink is investigated using Biot's dynamic theory of poroelasticity. Based on Biot's theory, the governing field equations are re‐formulated in frequency domain with solid displacement and pore pressure. In a cylindrical coordinate system, a method of displacement potentials for axisymmetric displacement field is proposed to decouple the Biot's field equations to three scalar Helmholtz equations, and then the general solution to axisymmetric problems are obtained. The full‐space fundamental singular solution for a point sink is also derived using potential methods. The mirror‐image method is finally applied to construct the fundamental solution for a point sink buried in a poroelastic half‐space. Furthermore, a numerical study is conducted for a rock, that is, Berea sandstone, as a representative example. Copyright © 2013 John Wiley & Sons, Ltd.
A survey on the spectral theory of nonnegative tensors
Authors: Chang Kungching , Qi Liqun , Zhang Tan
Published: October 2013

This is a survey paper on the recent development of the spectral theory of nonnegative tensors and its applications. After a brief review of the basic definitions on tensors, the H‐eigenvalue problem and the Z‐eigenvalue problem for tensors are studied separately. To the H‐eigenvalue problem for nonnegative tensors, the whole Perron–Frobenius theory for nonnegative matrices is completely extended, while to the Z‐eigenvalue problem, there are many distinctions and are studied carefully in details. Numerical methods are also discussed. Three kinds of applications are studied: higher order Markov chains, spectral theory of hypergraphs, and the quantum entanglement. Copyright © 2013 John Wiley & Sons, Ltd.
Mechanisms of age‐related macular degeneration and therapeutic opportunities
Authors: van Lookeren Campagne Menno , LeCouter Jennifer , Yaspan Brian L , Ye Weilan
Published: October 2013

As the age of the population increases in many nations, age‐related degenerative diseases pose significant socioeconomic challenges. One of the key degenerative diseases that compromise quality of life is age‐related macular degeneration (AMD). AMD is a multi‐faceted condition that affects the central retina, which ultimately leads to blindness in millions of people worldwide. The pathophysiology and risk factors for AMD are complex, and the symptoms manifest in multiple related but distinct forms. The ability to develop effective treatments for AMD will depend on a thorough understanding of the underlying pathophysiology, risk factors, and driver molecular pathways, as well as the ability to develop useful animal models. This review provides an overview of the aforementioned aspects in AMD. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Biomarkers of drugs targeting HER‐family signalling in cancer
Authors: Montemurro Filippo , Scaltriti Maurizio
Published: October 2013

The epidermal growth factor receptor family (EGFR/HER) is frequently deregulated in human cancers. Several aberrations at various levels have been successfully exploited as targets for anti‐cancer therapies. However, with very few exceptions, drugs targeting HER signalling have shown only modest activity when used alone in cancers where a HER‐related target can be identified. Optimization of the use of these drugs either alone or in combination with other anti‐cancer agents would require a more precise definition of alterations that could predict for activity or resistance. Clinical validation of the several potential biomarkers emerging from clinical and translational studies is a challenging process. Thanks to combined efforts, collection of tumour tissues and other potentially relevant patients' materials has become more and more frequently mandatory in prospective studies with biologically targeted therapies. As a consequence, information on the value of promising biomarkers of drugs targeting HER‐family receptor targeting is becoming available. This review will focus on breast cancer, where the HER2 subset has been the subject of a major research effort in the last two decades, and on gastric cancer, where HER2 targeting has emerged recently as a successful strategy. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
A Brief Understanding of Process Optimisation in Microwave‐assisted Extraction of Botanical Materials: Options and Opportunities with Chemometric Tools
Authors: Das Anup Kumar , Mandal Vivekananda , Mandal Subhash C.
Published: October 2013

Introduction

Extraction forms the very basic step in research on natural products for drug discovery. A poorly optimised and planned extraction methodology can jeopardise the entire mission.

Objective

To provide a vivid picture of different chemometric tools and planning for process optimisation and method development in extraction of botanical material, with emphasis on microwave‐assisted extraction (MAE) of botanical material.

Methods

A review of studies involving the application of chemometric tools in combination with MAE of botanical materials was undertaken in order to discover what the significant extraction factors were. Optimising a response by fine‐tuning those factors, experimental design or statistical design of experiment (DoE), which is a core area of study in chemometrics, was then used for statistical analysis and interpretations.

Results

In this review a brief explanation of the different aspects and methodologies related to MAE of botanical materials that were subjected to experimental design, along with some general chemometric tools and the steps involved in the practice of MAE, are presented. A detailed study on various factors and responses involved in the optimisation is also presented.

Conclusion

This article will assist in obtaining a better insight into the chemometric strategies of process optimisation and method development, which will in turn improve the decision‐making process in selecting influential extraction parameters. Copyright © 2013 John Wiley & Sons, Ltd.
Fetal kidneys: additional sonographic criteria of normal development
Authors: Devriendt Arnaud , Cassart Marie , Massez Anne , Donner Catherine , Avni Fred E.
Published: October 2013

Objective

The aim of this study was to establish objective criteria for the evaluation of cortical echogenicity (CE), cortical thickness (CT), and medullary thickness (MT), as well as the corticomedullary ratio (CMR), throughout gestation.

Method

In this prospective single‐center study, CE, MT, CT, and CMR were evaluated in a group of singleton pregnancies examined by ultrasound during the second and third trimesters.

Results

The CE evolved from a hyperechoic pattern compared with the liver or spleen during early second trimester to a hypoechogenic pattern in the third trimester, with no fetus displaying cortical hyperechogenicity after 32 weeks. CT increased from 1.8 to 2.5 mm (p < 0.05) from 21 to 25 to 34 to 37 weeks; MT from 2.7 to 5.1 mm (p < 0.0001), and the CMR decreased from 0.7 to 0.5 (p < 0.001).

Conclusion

The CE, CT, and MT evolve with gestation. Cortical hyperechogenicity compared with the liver or spleen after 32 weeks or a CMR above 0.7 in the third trimester should raise the suspicion of a fetal nephropathy. © 2013 John Wiley & Sons, Ltd.
Thoughening of poly(lactic acid) with silicone rubber
Authors: Yıldız Sibel , Karaağaç Bağdagül , Ozkoc Guralp
Published: October 2013

In this study, poly(lactic acid) (PLA) was blended with silicone rubber (SR) to improve its impact strength and toughness by using dynamic crosslinking in the presence of peroxide during melt compounding. The SR to PLA ratio, peroxide and coagent concentrations were taken as experimental parameters. Blends were evaluated in terms of their thermal properties, tensile and impact strengths, dynamic mechanical properties, and micro‐structure. Results showed that PLA was successfully toughened with SR using dynamic crosslinking. Impact strength and energy of fracture in tensile test improved up to 4 and 10 times, respectively. On the other hand, yield strength and stiffness of blends deteriorated by the incorporation of SR. Thermal analysis pointed out that presence of SR decreased the cold crystallization temperature. It was observed from scanning electron microscopy (SEM) that the energy absorbing mechanism under impact loads in PLA/SR blends is tortuosity in the crack patterns. POLYM. ENG. SCI., 54:2029–2036, 2014. © 2013 Society of Plastics Engineers
Extrusion of poly(ether imide) foams using pressurized CO2: Effects of imposition of supercritical conditions and nanosilica modifiers
Authors: Aktas Seda , Gevgilili Halil , Kucuk Ilknur , Sunol Aydin , Kalyon Dilhan M.
Published: October 2013

Foams of an engineering plastic, poly(ether imide), were extruded using a single screw extruder employing pressurized CO2 as the blowing agent. The porosity, pore size distributions, and the density of the foams were especially affected by the pressure drop, the pressure loss rate, and temperature at the die. Significant increases in porosity and pore size and corresponding decreases in density were observed when the pressure imposed on CO2 became greater than the critical pressure values of CO2 (i.e., the temperature was always greater than the critical temperature of the CO2 in the extruder and the die). The viscoelastic material functions of the extruded foams depended especially on the density of the foam, with the elastic modulus increasing with density. The incorporation of nanosilica particles in the 0.08–0.6% by weight range increased only the density of the foam and did not provide any benefits in controlling of the nucleation rate and the pore size distribution, presumably due to their poor dispersibility and agglomerated state in the single screw extruder. POLYM. ENG. SCI., 54:2064–2074, 2014. © 2013 Society of Plastics Engineers