bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal Employment During Pregnancy and Birth Outcomes: Evidence From Danish Siblings
Authors: Wüst Miriam
Published: April 2014

I use Danish survey and administrative data to examine the impact of maternal employment during pregnancy on birth outcomes. As healthier mothers are more likely to work and health shocks to mothers may impact employment and birth outcomes, I combine two strategies: First, I control extensively for time‐varying factors that may correlate with employment and birth outcomes, such as pre‐pregnancy family income and maternal occupation, pregnancy‐related health shocks, maternal sick listing, and health behaviors (smoking and alcohol consumption). Second, to account for remaining time‐invariant heterogeneity between mothers, I compare outcomes of mothers’ consecutive children. Mothers who work during the first pregnancy trimester have a lower risk of preterm birth. I find no effect on the probability of having a baby of small size for gestational age. To rule out that health selection of mothers between pregnancies drives the results, I focus on mothers whose change in employment status is likely not to be driven by underlying health (mothers who are students in one of their pregnancies and mothers with closely spaced births). Given generous welfare benefits and strict workplace regulations in Denmark, my findings support a residual explanation, namely, that exclusion from employment may stress mothers in countries with high‐female employment rates. Copyright © 2014 John Wiley & Sons, Ltd.
Systematic implicit solvent coarse graining of dimyristoylphosphatidylcholine lipids
Authors: Mirzoev Alexander , Lyubartsev Alexander P.
Published: April 2014

We have used systematic structure‐based coarse graining to derive effective site–site potentials for a 10‐site coarse‐grained dimyristoylphosphatidylcholine (DMPC) lipid model and investigated their state point dependence. The potentials provide for the coarse‐grained model the same site–site radial distribution functions, bond and angle distributions as those computed in atomistic simulations carried out at four different lipid–water molar ratios. It was shown that there is a non‐negligible dependence of the effective potentials on the concentration at which they were generated, which is also manifested in the properties of the lipid bilayers simulated using these potentials. Thus, effective potentials computed at low lipid concentration favor to more condensed and ordered structure of the bilayer with lower average area per lipid, while potentials obtained at higher lipid concentrations provide more fluid‐like structure. The best agreement with the reference data and experiment was achieved using the set of potentials derived from atomistic simulations at 1:30 lipid:water molar ratio providing fully saturated hydration of DMPC lipids. Despite theoretical limitations of pairwise coarse‐grained potentials expressed in their state point dependence, all the resulting potentials provide a stable bilayer structure with correct partitioning of different lipid groups across the bilayer as well as acceptable values of the average lipid area, compressibility and orientational ordering. In addition to bilayer simulations, the model has proven its robustness in modeling of self‐aggregation of lipids from randomly dispersed solution to ordered bilayer structures, bicelles, and vesicles. © 2014 Wiley Periodicals, Inc.
Direct Constructions for General Families of Cyclic Mutually Nearly Orthogonal Latin Squares
Authors: Demirkale Fatih , Donovan Diane , Khodkar Abdollah
Published: April 2014

Two Latin squares and , of even order n with entries , are said to be nearly orthogonal if the superimposition of L on M yields an array in which each ordered pair , and , occurs at least once and the ordered pair occurs exactly twice. In this paper, we present direct constructions for the existence of general families of three cyclic mutually orthogonal Latin squares of orders , , and . The techniques employed are based on the principle of Methods of Differences and so we also establish infinite classes of “quasi‐difference” sets for these orders.
Statin‐Induced Impairment of Monocyte Migration Is Gender‐Related
Authors: Ruggieri Anna , Gambardella Lucrezia , Maselli Angela , Vona Rosa , Anticoli Simona , Panusa Alessia , Malorni Walter , Matarrese Paola
Published: April 2014

Statins, widely used for treatment of hypercholesterolemia, have been demonstrated to exert pleiotropic beneficial effects independently of their cholesterol‐lowering action, such as anti‐inflammatory activity. A gender disparity has been observed in their cholesterol lowering activity as well as in response to these “off label” effects. Monocytes play a central role in atherosclerotic disease and, more in general, in inflammatory responses, through their chemotactic function and cytokine production. On these bases, in the present work, we examined the effect of statins on homeostasis and migration properties of freshly isolated monocytes from male and female healthy donors. Two prototypic natural and synthetic statins with different polarity, that is, type 1 and type 2 statins, have been considered: simvastatin and atorvastatin. Freshly isolated monocytes from peripheral blood of male and female healthy donors were treated with these drugs in the absence or presence of lipopolysaccharide (LPS) stimulation. Results obtained indicated that the polar statin efficiently inhibited chemotaxis of monocytes more than the apolar statin and that this effect was more significantly induced in cells from females than in cells from males. Dissecting the mechanisms involved, we found that these results could mainly be due to differential effects on: (i) the release of key cytokines, for example, MCP‐1 and TNF‐α; (ii) the maintenance of the redox homeostasis; (iii) a target activity on microfilament network integrity and function. All in all these results could suggest a reappraisal of “off‐label” effects of statins taking into account either their chemical structure, that is, molecular polarity, or the gender issue. J. Cell. Physiol. 229: 1990–1998, 2014. © 2014 Wiley Periodicals, Inc.
Analysis of the mechanisms of bioelectrochemical methane production by mixed cultures
Authors: van Eerten‐Jansen Mieke C. A. A. , Jansen Nina C. , Plugge Caroline M. , de Wilde Vinnie , Buisman Cees J. N. , ter Heijne Annemiek
Published: April 2014

BACKGROUND

In a methane‐producing bioelectrochemical system (BES) microorganisms grow on an electrode and catalyse the conversion of CO2 and electricity into methane. Theoretically, methane can be produced bioelectrochemically from CO2 via direct electron transfer or indirectly via hydrogen, acetate or formate. Understanding the electron transfer mechanisms could give insight into methods to steer the process towards higher rate.

RESULTS

In this study, the electron transfer mechanisms of bioelectrochemical methane production by mixed cultures were investigated. At a cathode potential of −0.7 V vs. normal hydrogen electrode (NHE), average current density was 2.9 A m−2 cathode and average methane production rate was 1.8 mole e− eq m−2 cathode per day (5.2 L CH4 m−2 cathode per day). Methane was primarily produced indirectly via hydrogen and acetate. Methods to steer towards bioelectrochemical hydrogen and acetate production to further improve the performance of a methane‐producing BES are discussed.

CONCLUSION

At cathode potentials equal to or lower than −0.7 V vs. NHE and using mixed cultures, methane was primarily produced indirectly via hydrogen and acetate. (Bio)electrochemical hydrogen and acetate production rate could be increased by optimizing the cathode design and by enriching the microbial community. Consequently, the production rate of CO2‐neutral methane in a BES could be increased. © 2014 Society of Chemical Industry
An image processing pipeline to detect and segment nuclei in muscle fiber microscopic images
Authors: Guo Yanen , Xu Xiaoyin , Wang Yuanyuan , Wang Yaming , Xia Shunren , Yang Zhong
Published: April 2014

Muscle fiber images play an important role in the medical diagnosis and treatment of many muscular diseases. The number of nuclei in skeletal muscle fiber images is a key bio‐marker of the diagnosis of muscular dystrophy. In nuclei segmentation one primary challenge is to correctly separate the clustered nuclei. In this article, we developed an image processing pipeline to automatically detect, segment, and analyze nuclei in microscopic image of muscle fibers. The pipeline consists of image pre‐processing, identification of isolated nuclei, identification and segmentation of clustered nuclei, and quantitative analysis. Nuclei are initially extracted from background by using local Otsu's threshold. Based on analysis of morphological features of the isolated nuclei, including their areas, compactness, and major axis lengths, a Bayesian network is trained and applied to identify isolated nuclei from clustered nuclei and artifacts in all the images. Then a two‐step refined watershed algorithm is applied to segment clustered nuclei. After segmentation, the nuclei can be quantified for statistical analysis. Comparing the segmented results with those of manual analysis and an existing technique, we find that our proposed image processing pipeline achieves good performance with high accuracy and precision. The presented image processing pipeline can therefore help biologists increase their throughput and objectivity in analyzing large numbers of nuclei in muscle fiber images. Microsc. Res. Tech. 77:547–559, 2014. © 2014 Wiley Periodicals, Inc.
Prevalence of HBV, HDV, HCV, and HIV infection during pregnancy in northern Benin
Authors: De Paschale Massimo , Ceriani Cristina , Cerulli Teresa , Cagnin Debora , Cavallari Serena , Ndayaké Joseph , Zaongo Dieudonné , Priuli Gianbattista , Viganò Paolo , Clerici Pierangelo
Published: April 2014

Pregnant women are not screened for HBsAg and anti‐HCV antibodies in many African countries. As there are few data concerning the prevalence of HBV, HDV, and HCV serological markers in Benin, the aim of this study was to evaluate their 2011 prevalence in pregnant women undergoing HIV screening in a rural area of north Benin, and compare the data with those reported for the same area in 1986. The sera of 283 women were examined for HBsAg, anti‐HBs, anti‐HBc, anti‐HCV, and anti‐HIV 1/2 antibodies. In the case of HBsAg positivity, a search was made for the HBeAg, anti‐HDV, and HBV genotypes; in the case of anti‐HCV positivity, a search was made for the HCV genotypes. HBsAg, anti‐HBs, anti‐HBc, anti‐HCV, and anti‐HIV 1/2 were positive in respectively 44 (15.5%), 82 (29.0%), 234 (82.7%), 21 (7.4%), and nine samples (3.2%). Of the HBsAg‐positive samples, five (11.4%) were positive for HBeAg, five (11.4%) for anti‐HDV, and 19 for HBV genotype E. Of the anti‐HCV‐positive samples, five were positive for genotype 2a/2c and one for genotype 1a. The prevalence of anti‐HBc alone (HBsAg and anti‐HBs negative) was very high (41.3%). In comparison with the 1986 data, the prevalence of HBsAg and anti‐HBc remained unchanged, that of HBeAg and anti‐HDV had decreased, and that of anti‐HIV 1/2 had increased. As these data confirm that HBV and HCV are highly endemic in the study area, it may be appropriate to introduce HBsAg and anti‐HCV screening for pregnant women. J. Med. Virol. 86:1281–1287, 2014. © 2014 Wiley Periodicals, Inc.
Thunderstorm climatology ofBrazil:ENSOandTropical Atlanticconnections
Authors: Pinto Osmar
Published: April 2014

In this report monthly thunderstorm days (TD) in 14 large cities of Brazil from 1951 to 2010 are compared with data obtained in the first part of the 20th century in the same cities and correlated with sea surface temperature (SST) of the equatorial Pacific Ocean and Tropical Atlantic Ocean. On average over all cities, 77 TD are reported each year after 1951, against 43 TD in the first part of the 20th century, an increase of 79%. The increase seems to be related to increase in the urbanization in these cities, and not to global warming. A comparative analysis of TD for the whole country with El Niño–Southern Oscillation (ENSO) events suggests that the tendency for El Niño to increase the thunderstorm activity is evident in the South (only in the Spring/Summer), Southeast, Northeast and North (only in the Fall/Winter) regions. Regarding the Tropical Atlantic OceanSST, a similar analysis using the Tropical South Atlantic (TSA) and Tropical North Atlantic (TNA) indices suggests that no significant differences exist between the thunderstorm activity for the two extreme positive and negativeTSAconditions in the South and Southeast regions, while in the Northeast and North regions there is a significant increase in the thunderstorm activity during extreme positiveTSA. Differently, only in the Northeast region there is a significant influence ofTNAon thunderstorm activity. The influence is such that the thunderstorm activity is larger for the extreme negativeTNAthan for extreme positiveTNA. All significant changes were quantified and significant variations were observed. For all parameters investigated (ENSO,TSAandTNA) the Northeast region showed the most significant changes.
Temperature sensitivity of plant phenology in temperate and subtropical regions of China from 1850 to 2009
Authors: Wang Huanjiong , Dai Junhu , Zheng Jingyun , Ge Quansheng
Published: April 2014

Phenology can be used to track plant responses to climate change. In China, several studies have found the earlier trends of spring phenophases over the past 50 years. However, few studies put these phenological changes into historical perspective. Based on specific phenophases records from historical diaries and Chinese Phenological Observation Network, we developed spring phenology index (SPI) time series in temperate and subtropical regions of eastern China from 1850 to 2009. We firstly compare the temporal change of SPI and seasonal temperature anomaly. Subsequently, we search for common shifts in phenological and temperature time series by applying the moving t‐test method, and discuss temperature sensitivity of SPI by using the moving linear regression method for both regions. Results show that the SPI in temperate region revealed lower interannual variability than in subtropical region, while the seasonal temperature variability was higher in temperate region. In temperate region, the timing of significant shift towards earlier SPI (in 1979) coincides with the timing of shift in spring temperature time series. The temperature sensitivities of SPI differ among the two regions. The mean sensitivity of SPI to spring temperature in subtropical region (−3.7 days °C−1) is stronger than in temperate region (−2.5 days °C−1). The temperature sensitivity of SPI varies among consecutive 30‐year periods. In recent three decades, temperature sensitivity of spring phenophases became stronger in both regions.
CO2 emissions from soils of different depths of a permafrost peatland, Northeast China: response to simulated freezing–thawing cycles
Authors: Wang Jiaoyue , Song Changchun , Hou Aixin , Wang Lili
Published: April 2014

Soil freezing–thawing cycle (FTC) is an important factor controlling C dynamics in mid–high latitude regions, especially in the permafrost regions impacted by global warming. Nonetheless, the response of C cycling in the deeper active layers of permafrost regions to FTC remains far from certain. We aimed to characterize the emission of CO2 from soils of multiple depths as impacted by FTC and its relationship with active organic C (OC) and enzyme activities. We collected soil samples from three soil layers (0–15, 15–30, and 30–45 cm) of an undisturbed peatland in the Da Xing'anling Mountains, NE China, and then subjected them to various freezing (10 to –10°C) and thawing (–10 to 10°C) cycles. Soil CO2 emissions, two active OC fractions, and activities of three enzymes were monitored during incubation periods. At the thawing stage of the first FTC, CO2 emission rates in the three soil layers presented transient peaks being ≈ 1.6–1.7 times higher than those of the unfrozen control sample. Although FTC did not change the overall patterns of decreasing CO2 emission along the soil profile, FTC significantly reduced the amount of CO2 emission when compared with the unfrozen control sample, possibly because the small CO2 emission at the freezing stage neutralized the peak of CO2 emission at the thawing stage. This study suggests that in the active layer of permafrost peatlands, CO2 emission during FTCs may be lower than the emission under higher temperatures, but experiment with more temperature gradients should be encouraged to verify this conclusion in the future. Meanwhile, FTC significantly increased water extracted OC release from the three soil layers, ≈ 1.2–1.6 times higher compared to the unfrozen control sample, indicating that soil carbon loss in the form of leachate may increase during freezing–thawing periods. Additionally, the CO2 emissions impacted by FTCs were significantly correlated with active OC fractions and enzyme activities, which indicated that active OC and enzymes were sensitive to FTCs, and surviving microbes and enzymes might use the increased liable substrates and induce the CO2 emission during freezing–thawing periods.
Raman spectroscopic study of the degradation of a middle age mural painting: the role of agricultural activities
Authors: Veneranda Marco , Irazola Mireia , Díez Marta , Iturregui Ane , Aramendia Julene , Castro Kepa , Madariaga Juan Manuel
Published: April 2014

The present work was focused on the investigation of the original and decayed materials as well as the degradation phenomena affecting the middle age mural painting preserved in the Assumption's church of Alaiza (Basque Country, Spain). Portable Raman spectroscopy assisted with energy dispersive X‐ray fluorescence was used to identify the nature of the original compounds and to distinguish them from the following: (1) those used in recent restorations and (2) those considered as decaying compounds. The information obtained by this technique was used to select the sampling areas to perform laboratory Raman measurements and soluble salt test, supported by the use of ion chromatography in an attempt to clarify the degradation processes of the mural paintings. These analyses suggested the connection of the deterioration problems with the agricultural activity of the environment surrounding the church. For example, the use of industrial common salt (unpurified NaCl) against the snow and ice, as well as common fertilizers such as NH4NO3 and (NH4)2SO4, generates Na+ and NH4+ cations together with Cl−, NO3−, and SO42−anions that ascent the basal part of the walls causing the decarbonation of calcite and the subsequent disintegration of the mortar. Sulfate compounds were detected in the lower parts of the walls (below half a meter), while nitrate compounds were detected in the higher parts, at heights greater than 1 m. This work is a clear example of the conservation problems in cultural heritage related to the characteristics of the surrounding environment. Copyright © 2014 John Wiley & Sons, Ltd.
Vestibular suppressants after canalith repositioning in benign paroxysmal positional vertigo
Authors: Kim Min‐Beom , Lee Hyun S. , Ban Jae H.
Published: April 2014

Objectives/Hypothesis

To investigate the characteristics of residual symptoms and to evaluate the effects of adjuvant vestibular suppressants on residual symptoms after successful canalith repositioning procedures (CRPs).

Study Design

Individual randomized controlled trial.

Methods

One hundred fifty patients with idiopathic benign paroxysmal positional vertigo who achieved successful CRPs on initial visit participated in this study. Dizziness Handicap Inventory (DHI) questionnaires were completed before CRPs. All study populations were divided into three groups after successful CRPs on the initial visit day: the medication (V) group (treated with a vestibular suppressant [dimenhydrinate 50 mg per day]), the placebo (P) group, and the no medication (N) group. One week after successful CRPs, residual symptoms were checked and repeated DHI questionnaires were completed to compare residual symptoms.

Results

Among the 138 patients who did not show positional nystagmus at follow‐up, 67 (48.5%) complained of residual symptoms. The presence of residual symptoms was more prevalent in the P and N group compared with the V group (P = .035, P = .017, respectively). The most frequent residual symptom was lightheadedness (n = 42). Moreover, in the V group, lightheadedness was significantly reduced compared with the P group (P = .029). However, in the analysis of DHI, total and subscale scores did not differ across the three groups before or after successful CRP.

Conclusions

Vestibular suppressants significantly reduced residual symptoms compared to both placebo and no medication after CRP. However, there was no significant reduction in DHI score compared with the control group, suggesting that the residual symptoms could not be evaluated by DHI score alone.

Level of Evidence

1b Laryngoscope 124:2400–2403, 2014
Posterior cricoarytenoid muscle dynamics in canines and humans
Authors: Chhetri Dinesh K. , Neubauer Juergen , Sofer Elazar
Published: April 2014

Objectives/Hypothesis

The posterior cricoarytenoid (PCA) muscle is the sole abductor of the glottis and serves important functions during respiration, phonation, cough, and sniff. The present study examines vocal fold abduction dynamics during PCA muscle activation.

Study Design

Basic science study using an in vivo canine model and human subjects.

Methods

In four canines and five healthy humans vocal fold abduction time was measured using high‐speed video recording. In the canines, PCA muscle activation was achieved using graded stimulation of the PCA nerve branch. The human subjects performed coughing and sniffing tasks. High‐speed video and audio signals were concurrently recorded.

Results

In the canines, the vocal fold moved posteriorly, laterally, and superiorly during abduction. Average time to reach 10%, 50%, and 90% abduction was 23, 50, and 100 ms with low stimulation; 24, 58, and 129 ms with medium stimulation; and 21, 49, and 117 ms with high‐level stimulation, respectively. In the humans, 100% abduction times for coughing and sniffing tasks were 79 and 193 ms, respectively.

Conclusions

The PCA abduction times in canines are within the range in humans. The results also further support the notion that PCA muscles are fully active during cough.

Level of Evidence

NA Laryngoscope, 124:2363–2367, 2014
Combined hepatocellular-cholangiocarcinoma: A population-level analysis of an uncommon primary liver tumor
Authors: Garancini Mattia , Goffredo Paolo , Pagni Fabio , Romano Fabrizio , Roman Sanziana , Sosa Julie Ann , Giardini Vittorio
Published: April 2014

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare primary liver cancer. Our aims were to analyze the demographic, clinical, and pathological characteristics of cHCC-CC at a population level and to investigate the effects of these features as well as different management strategies on the prognosis. The Surveillance, Epidemiology, and End Results (SEER) database was analyzed for 1988–2009. Data analyses were performed with chi-square tests, analyses of variance, Kaplan-Meier curves, and Cox proportional hazards regression. Four hundred sixty-five patients with cHCC-CC, 52,825 patients with hepatocellular carcinoma (HCC), and 7181 patients with cholangiocarcinoma (CC) were identified. cHCC-CC was more common in patients who were white, male, and older than 65 years. Treatment was more frequently nonsurgical/interventional. Patients with cHCC-CC, HCC, and CC had 5-year overall survival (OS) and disease-specific survival rates of 10.5%, 11.7%, and 5.7% (P < 0.001) and 17.8%, 21.0%, and 11.9% (P < 0.001), respectively. For cHCC-CC patients, an increasing invasiveness of the therapeutic approach was significantly associated with prolonged survival (P < 0.001). In a multivariate model, black race, a distant SEER stage, and a tumor size of 5.0 to 10.0 cm were independently associated with lower survival for cHCC-CC patients; a year of diagnosis after 1995 and surgical treatment with minor hepatectomy, major hepatectomy (MJH), or liver transplantation (LT) were independently associated with better survival for cHCC-CC patients. Patients diagnosed with cHCC-CC, HCC, and CC and treated with LT had 5-year OS rates of 41.1%, 67.0%, and 29.0%, respectively (P < 0.001). In conclusion, cHCC-CC patients appear to have intermediate demographic, clinical, and survival characteristics in comparison with HCC and CC patients. cHCC-CC patients undergoing LT showed inferior survival in comparison with HCC patients, and the role and indications for LT in cHCC-CC have yet to be defined. At this time, MJH may be considered the best therapeutic approach for such patients. Liver Transpl 20:952–959, 2014. © 2014 AASLD.
Comparative effectiveness of liver transplant strategies for end-stage liver disease patients on renal replacement therapy
Authors: Chang Yaojen , Gallon Lorenzo , Jay Colleen , Shetty Kirti , Ho Bing , Levitsky Josh , Baker Talia , Ladner Daniela , Friedewald John , Abecassis Michael , Hazen Gordon , Skaro Anton I.
Published: April 2014

There are complex risk-benefit tradeoffs with different transplantation strategies for end-stage liver disease patients on renal support. Using a Markov discrete-time state transition model, we compared survival for this group with 3 strategies: simultaneous liver-kidney (SLK) transplantation, liver transplantation alone (LTA) followed by immediate kidney transplantation if renal function did not recover, and LTA followed by placement on the kidney transplant wait list. Patients were followed for 30 years from the age of 50 years. The probabilities of events were synthesized from population data and clinical trials according to Model for End-Stage Liver Disease (MELD) scores (21-30 and >30) to estimate input parameters. Sensitivity analyses tested the impact of uncertainty on survival. Overall, the highest survival rates were seen with SLK transplantation for both MELD score groups (82.8% for MELD scores of 21-30 and 82.5% for MELD scores > 30 at 1 year), albeit at the cost of using kidneys that might not be needed. Liver transplantation followed by kidney transplantation led to higher survival rates (77.3% and 76.4%, respectively, at 1 year) than placement on the kidney transplant wait list (75.1% and 74.3%, respectively, at 1 year). When uncertainty was considered, the results indicated that the waiting time and renal recovery affected conclusions about survival after SLK transplantation and liver transplantation, respectively. The subgroups with the longest durations of pretransplant renal replacement therapy and highest MELD scores had the largest absolute increases in survival with SLK transplantation versus sequential transplantation. In conclusion, the findings demonstrate the inherent tension in choices about the use of available kidneys and suggest that performing liver transplantation and using renal transplantation only for those who fail to recover their native renal function could free up available donor kidneys. These results could inform discussions about transplantation policy. Liver Transpl 20:1034-1044, 2014. © 2014 AASLD.
Trend of Histone Deacetylase Inhibitors in Cancer Therapy: Isoform Selectivity or Multitargeted Strategy
Authors: Zhang Lei , Han Yantao , Jiang Qixiao , Wang Chunbo , Chen Xuehong , Li Xiaoguang , Xu Fuming , Jiang Yuqi , Wang Qiang , Xu Wenfang
Published: April 2014

Pharmacological inhibition of histone deacetylases (HDACs) has been successfully applied in the treatment of a wide range of disorders, including Parkinson's disease, infection, cardiac diseases, inflammation, and especially cancer. HDAC inhibitors (HDACIs) have been proved to be effective antitumor agents by various stages of investigation. At present, there are two opposite focuses of HDACI design in the cancer therapy, highly selective inhibitor strategy and dual‐ or multitargeted inhibitors. The former method, which is supposed to elucidate the function of individual HDAC and provide candidate inhibitors with fewer side effects, has been widely accepted by the inhibitor developer. The latter approach, though less practiced, has promising potential for the antitumor therapy based on HDACIs. Effective HDACIs, some of which are in clinic anticancer research, have been developed by both methods. In order to gain insight into HDACI design, the strategies and achievements of the two diverse methods are reviewed.
The Calculation of Molecular Structural Similarity: Principles and Practice
Authors: Willett Peter
Published: April 2014

Measures of structural similarity play an important role in chemoinformatics for applications such as similarity searching, database clustering and molecular diversity analysis. A similarity measure comprises three components: a structure representation; a weighting scheme; and a similarity coefficient. The paper introduces these components and describes methods for comparing different measures. The use of similarity measures in chemoinformatics research is illustrated by recent projects in the author’s laboratory on: the interactions between a weighting scheme and a similarity coefficient; the design of comparative studies of similarity measures; the use of 2D fingerprints for scaffold‐hopping searches; and the registration of orphan drugs for rare diseases.
Exploring Activity Cliffs from a Chemoinformatics Perspective
Authors: Bajorath Jürgen
Published: April 2014

The activity cliff concept experiences considerable interest in medicinal chemistry and chemoinformatics. Activity cliffs are defined as pairs or groups of structurally similar or analogous active compounds having large differences in potency. Depending on the research field, views of activity cliffs partly differ. While interpretability and utility of activity cliff information is considered to be of critical importance in medicinal chemistry, large‐scale exploration and prediction of activity cliffs are of special interest in chemoinformatics. Much emphasis has recently been put on making activity cliff information accessible for medicinal chemistry applications. Herein, different approaches to the analysis and prediction of activity cliffs are discussed that are of particular relevance from a chemoinformatics viewpoint.
Real‐time homonuclear broadband and band‐selective decoupled pure‐shift ROESY
Authors: Kakita Veera Mohana Rao , Bharatam Jagadeesh
Published: April 2014

Unambiguous spectral assignments in 1H solution‐state NMR are central, for accurate structural elucidation of complex molecules, which is often hampered by signal overlap, primarily because of scalar coupling multiplets, even at typical high magnetic fields. The recent advances in homodecoupling methods have shown powerful means of achieving high resolution pure‐shift 1H spectra in 1D and also in 2D J‐correlated experiments, by effectively collapsing the multiplet structures. The present work extends these decoupling strategies to through‐space correlation experiments as well and describes two new pure‐shift ROESY pulse schemes with homodecoupling during acquisition, viz., homodecoupled broadband (HOBB)‐ROESY and homodecoupled band‐selective (HOBS)‐ROESY. Furthermore, the ROESY blocks suppress the undesired interferences of TOCSY cross peaks and other offsets. Despite the reduced signal sensitivity and prolonged experimental times, the HOBB‐ROESY is particularly useful for molecules that exhibit an extensive scalar coupling network spread over the entire 1H chemical shift range, such as natural/synthetic organic molecules. On the other hand, the HOBS‐ROESY is useful for molecules that exhibit well‐separated chemical shift regions such as peptides (NH, Hα and side‐chain protons). The HOBS‐ROESY sensitivities are comparable with the conventional ROESY, thereby saves the experimental time significantly. The power of these pure‐shift ROESY sequences is demonstrated for two different organic molecules, wherein complex conventional ROE cross peaks are greatly simplified with high resolution and sensitivity. The enhanced resolution allows deriving possibly more numbers of ROEs with better accuracy, thereby facilitating superior means of structural characterization of medium‐size molecules. Copyright © 2014 John Wiley & Sons, Ltd.
Moisture uptake and resulting mechanical response of bio‐based composites. II. composites
Authors: Doroudgarian Newsha , Pupure Liva , Joffe Roberts
Published: April 2014

The durability of entirely bio‐based composites with respect to the exposure to elevated humidity was evaluated. Different combinations of bio‐based resins (Tribest, EpoBioX, Envirez) and cellulosic fibers (flax and regenerated cellulose fiber rovings and fabrics) were used to manufacture unidirectional and cross‐ply composite laminates. Water absorption experiments were performed at various humidity levels (41%, 70%, and 98%) to measure apparent diffusion coefficient and moisture content at saturation. Effect of chemical treatment (alkali and silane) of fibers as protection against moisture was also studied. However, fiber treatment did not show any significant improvement and in some cases the performance of the composites with treated fibers was lower than those with untreated reinforcement. The comparison of results for neat resins and composites showed that moisture uptake in the studied composites is primarily due to cellulosic reinforcement. Tensile properties of composites as received (RH = 24%) and conditioned (RH = 41%, 70%, and 98%) were measured in order to estimate the influence of humidity on behavior of these materials. Results were compared with data for glass fiber reinforced composite, as a reference material. Previous results from study of unreinforced polymers showed that resins were resistant to moisture uptake. Knowing that moisture sorption is primarily dominated by natural fibers, the results showed that some of the composites with bio‐based resins performed very well and have comparable properties with composites of synthetic epoxy, even at elevated humidity. POLYM. COMPOS., 36:1510–1519, 2015. © 2014 Society of Plastics Engineers
Effect of formaldehyde/phenol ratio (F/P) on the properties of phenolic resins and foams synthesized at room temperature
Authors: Hu Xiang‐Ming , Zhao Yan‐Yun , Cheng Wei‐Min
Published: April 2014

Six types of phenolic foaming resins were synthesized at room temperature with different formaldehyde/phenol (F/P) ratios in this study. The effects of F/P ratios on physicochemical characteristics and foaming properties of the resulting resins were analyzed based on viscosity, solids content, hydroxymethyl index, residual monomer content, molecular structure of the foaming resin, flame retardancy, and foam compression strength measurements. The results of the present study indicated that viscosity and solids content of the foaming resins increased with an increase in F/P; the hydroxymethyl index of the resin first increased and then decreased with an increase in F/P, reaching its maximum at F/P = 1.6; the trimer, tetramer, and pentamer contents of the resins increased with an increase in F/P. Nuclear magnetic resonance (13C NMR) spectral analysis indicated that the presence of para/para‐methylene, para‐hydroxymethyl, and ortho‐hydroxymethyl groups in the resin gradually increased with an increase in F/P; the proportions of ortho/ortho‐ and ortho/para‐methylene bonds of the resin increased as F/P was increased. The increase in F/P was demonstrated to be conducive to improving the compression strength, thermal stability, and flame retardancy of the phenolic foam and reducing its peak heat release rate and total smoke release. The morphology of phenolic foams show that the closed cell content in the PF foam increases with the F/P ratio until it reaches a ratio of 1.6. Furthermore, the cell size becomes more uniform. POLYM. COMPOS., 36:1531–1540, 2015. © 2014 Society of Plastics Engineers
High stability of photoinduced merocyanine in naphthopyran‐doped polyvinylpyrrolidone electrospun nanofibers
Authors: Liu Lihui , Zhang Yunfeng , Wang Guang , Zhang Meiduo , Guan Hongyu
Published: April 2014

Highly stable merocyanines (MCs) of naphthopyrans based on polyvinylpyrrolidone (PVP) nanofibers have been developed by electrospinning mixtures of PVP and naphthopyran derivatives. The surface and internal features of the electrospun fibers were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. The naphthopyrans displayed normal photochromic performance in the polymeric fibers and presented high‐stability MC forms. The one‐dimensional structure of the nanofibers and hydrogen bonds between PVP and MC structures of naphthopyran were responsible for the high degree of stability. The absorption intensities of the most highly stable MC form were 77% compared with the initial intensity after fading for three days. © 2014 Society of Chemical Industry
Charge‐selective separation and recovery of organic ions by polymeric micelles
Authors: Wan Decheng , Jin Ming , Pu Hongting
Published: April 2014

Charge‐selective separation and recovery of organic ionic dyes by polymeric micelles (PMs) are reported. Branched polyethylenimine (PEI) functionalized with 4‐cetyloxybenzaldehyde (CBA) via Schiff‐base bonds (PEI@CBA) can extract an anionic dye from cationic contaminants, and transfer it from an aqueous phase into an apolar oil phase, and thus leading to separation. While a physical micelle of PAA@PS, with polyacrylic acid (PAA) as core and polystyrene (PS) as shell, can selectively extract a cationic dye from anionic contaminants. When polar, yet nonionic groups are eliminated from the core of a PM, charge selectivity can be significantly enhanced. Although many anionic–cationic dyes can form a poorly water‐soluble complex or precipitate, separation is still feasible with a reasonably designed PM. Finally, entrapment of a guest by a PM is found easy but release may be difficult; in this case, PEI@CBA with an acid‐sheddable shell, can recover the entrapped guest. It is also found the encapsulation of a dye is usually accompanied with dye stacking, resulting in a changed UV/vis spectrum. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 872–881
Crystallization in PHB/DGEBA blends
Authors: Tognana Sebastián , Silva Leonel , Salgueiro Walter
Published: April 2014

Real‐time experiments using small‐angle X‐ray scattering and differential scanning calorimetry on blends of the semicrystalline polyester poly(3‐hydroxybutyrate) (PHB) and amorphous monomer epoxy DGEBA (diglycidyl ether of bisphenol A) were performed. Differences in the processes of melting and re‐crystallization were observed in blends relative to pure PHB. The results obtained in this study indicated that re‐crystallization is more important in blends with 50% DGEBA than in pure PHB. Moreover, segregation toward the interfibrillar region would facilitate re‐crystallization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 882–886
Growth of Fe nanocrystals on LaAlO3 (001) and epitaxial relationship determination by RHEED and XPS
Authors: Zanouni Mohamed , Denys Emmanuel , Derivaz Mickael , Dentel Didier , Diani Mustapha , Azzouz Chiraz Ben , Bischoff Jean‐Luc
Published: April 2014

Non‐volatiles flash memories embedding nanocrystals are promising devices. These memories are made of semiconducting or metallic nanostructures inserted in an insulating matrix. SiO2, traditionally used as an insulator, is gradually replaced by high‐dielectric materials called “high‐k” oxides, to reduce leakage currents. In this context, we used a crystalline lanthanum aluminate (LaAlO3) oxide. The magnetic properties of nanoparticles of Fe can increase the storage capacity in the memories compared to the semiconductor nanostructures as Si or Ge. Memories combining these two materials require complex monolithic structures such as “LaAlO3/Fe/LaAlO3/Si(001)”. In this context we have studied the initial growth of Fe on a solid substrate of LaAlO3 (001). Fe deposits were performed by molecular beam epitaxy (MBE) at different substrate temperatures. Chemical and structural properties were investigated by X‐ray photoelectron spectroscopy (XPS) and reflection high‐energy electron diffraction (RHEED). The temperature dependence study indicates that the growth of Fe on LaAlO3 is epitaxial with a single epitaxial relationship in a tight temperature window around 500 °C. The plane (001) of Fe is parallel with the LaAlO3(001) surface, but the iron unit cell is rotated of 45° around the growth direction compared with the substrate one (<100>Fe // <110>LaAlO3). This configuration minimizes the elastic strain of the Fe which grow with the Volmer‐Weber mode. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of solar radiation on the performance of organic solar cell
Authors: Guechi Abla , Chegaar Mohamed , Merabet Abdelali
Published: April 2014

The electrical current generated by the solar cells is very sensitive to the incident spectral distribution and intensity. This distribution varies greatly during the day due to changes in the sun's position or weather conditions. This work investigates the feasibility of using a solar spectral radiation model SMARTS2 to estimate the global solar irradiance and assess the influence of solar spectrum on the conversion efficiency of the organic thin film solar cells (PBDTTT) (poly[4,8‐bis‐substituted‐benzo[1,2‐b:4,5‐b0]dithiophene‐2,6‐diyl‐alt‐4‐substituted‐ thieno[3, 4‐b]thiophene‐ 2,6‐diyl])). The variation of the common performance indicators such as short circuit current, fill factor, open circuit voltage, and efficiency are shown and discussed for each month. The results show that the variations in the solar spectrum affect the different materials to different extent. The maximum efficiency is obtained in the summer months; however the lower efficiency is obtained during winter. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On replica symmetry of large deviations in random graphs
Authors: Lubetzky Eyal , Zhao Yufei
Published: April 2014

The following question is due to Chatterjee and Varadhan (2011). Fix and take , the Erdős‐Rényi random graph with edge density p, conditioned to have at least as many triangles as the typical . Is G close in cut‐distance to a typical
? Via a beautiful new framework for large deviation principles in , Chatterjee and Varadhan gave bounds on the replica symmetric phase, the region of where the answer is positive. They further showed that for any small enough p there are at least two phase transitions as r varies. We settle this question by identifying the replica symmetric phase for triangles and more generally for any fixed d‐regular graph. By analyzing the variational problem arising from the framework of Chatterjee and Varadhan we show that the replica symmetry phase consists of all such that lies on the convex minorant of where is the rate function of a binomial with parameter p. In particular, the answer for triangles involves rather than the natural guess of where symmetry was previously known. Analogous results are obtained for linear hypergraphs as well as the setting where the largest eigenvalue of is conditioned to exceed the typical value of the largest eigenvalue of . Building on the work of Chatterjee and Diaconis (2012) we obtain additional results on a class of exponential random graphs including a new range of parameters where symmetry breaking occurs. En route we give a short alternative proof of a graph homomorphism inequality due to Kahn (2001) and Galvin and Tetali (2004). © 2014 Wiley Periodicals, Inc. Random Struct. Alg., 47, 109–146, 2015
A design‐by‐treatment interaction model for network meta‐analysis with random inconsistency effects
Authors: Jackson Dan , Barrett Jessica K. , Rice Stephen , White Ian R. , Higgins Julian P.T.
Published: April 2014

Network meta‐analysis is becoming more popular as a way to analyse multiple treatments simultaneously and, in the right circumstances, rank treatments. A difficulty in practice is the possibility of ‘inconsistency’ or ‘incoherence’, where direct evidence and indirect evidence are not in agreement. Here, we develop a random‐effects implementation of the recently proposed design‐by‐treatment interaction model, using these random effects to model inconsistency and estimate the parameters of primary interest. Our proposal is a generalisation of the model proposed by Lumley and allows trials with three or more arms to be included in the analysis. Our methods also facilitate the ranking of treatments under inconsistency. We derive R and I2 statistics to quantify the impact of the between‐study heterogeneity and the inconsistency. We apply our model to two examples. © 2014 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd.
Coherence decay and its impact on sound radiation by wavepackets
Authors: Cavalieri André V. G. , Agarwal Anurag
Published: April 2014

Wavepackets obtained by a linear stability analysis of the turbulent mean flow were shown in recent works to agree closely with some relevant statistics of turbulent jets, such as power spectral densities and averaged phases of flow fluctuations. However, when such wavepacket models were used to calculate the far-field sound, satisfactory agreement was only obtained for flows that were supersonic relative to the ambient speed of sound; attempts with subsonic flows led to errors of more than an order of magnitude. We investigate here the reasons for such discrepancies by developing the integral solution of the Helmholtz equation in terms of the cross-spectral densities of turbulent quantities. It is shown that agreement of a statistical source, such as would be obtained by the above-mentioned wavepacket models, in averaged amplitudes and phases in the near field is not a sufficient condition for exact agreement of the far-field sound. The sufficient condition is that, in addition to the amplitudes and phases, the statistical source should also match the coherence function of the flow fluctuations. This is exemplified in a model problem, where we show that the effect of coherence decay on sound radiation is more prominent for subsonic convection velocities, and its neglect leads to discrepancies of more than an order of magnitude in the far-field sound. For supersonic flows errors are reduced for the peak noise direction, but for other angles the coherence decay is also seen to have a significant effect. Coherence decay in the model source is seen to lead to similar decays in the coherence of two points in the far acoustic field, these decays being significantly faster for higher Mach numbers. The limitations of linear wavepacket models are illustrated with another simplified problem, showing that superposition of time-periodic solutions can lead to a correlation decay between two points. However, the coherence between any pair of points in such models remains unity, and cannot thus represent the behaviour observed in turbulent flows.
The detrimental effect of hydrodynamic interactions on the process of Brownian flocculation in shear flow
Authors: Mizerski Krzysztof A.
Published: April 2014

The problem of Brownian flocculation of spherical particles in strong shearing flow without hydrodynamic interactions is studied in detail using the singular perturbation method. All other types of interparticle interactions, such as van der Waals or Lennard-Jones forces, are also ignored. In the limit of strong external flow, the strength of which is measured by the Péclet number ($Pe\gg 1$), a complicated boundary layer structure for the pair probability density function ($P_{2}$) is identified and the complete stationary spatial distribution of $P_{2}(\boldsymbol {x})$ in the domain is found. The results, in particular the total mass flux in the accumulation process, are compared qualitatively and quantitatively with the case where the spheres interact hydrodynamically and it is demonstrated that the hydrodynamic interactions tend to decrease the rate of flocculation. An explicit simple formula for the flocculation rate for a general form of hydrodynamic interactions is provided. The limit of small Péclet number is also discussed to confirm the conclusion on the detrimental influence of hydrodynamic interactions on the rate of Brownian flocculation in shearing flow.