bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexible Workplace Practices: Employees’ Experiences in Small IT Firms
Authors: Gordon Catherine E.
Published: February 2015

This paper examines how employees experience flexible workplace practices (FWPs), such as flex-time, in the context of small firms. Past research consistently documents that employees’ experiences vary according to whether or not the workplace culture is supportive of FWPs and work-life balance needs. Studies, however, typically use individual level data or focus on large companies. Little research has focused on the experiences of employees of small firms. Possibly, employees of small firms have somewhat unique experiences of FWPs because of the workplace context. Like past research, this paper considers how gender and age relations structure the workplace. Also taken into account are the control strategies that management employs over the workforce.

Data are taken from a Canadian study on small information technology (IT) firms that employed between four and 21 individuals. A multiple case study of 17 firms is conducted using web-surveys, semi-structured interviews, case study reports, field notes, and HR policy documents. Three different workplace contexts emerged among study firms based on their flexibility and workplace culture with respect to time. Some of these workplaces reproduced hegemonic gender, age, and class expectations, whereas others somewhat challenged them. The three firm-types did not vary according to firm-specific characteristics, such as business specialization, but patterns with regard to age and gender characteristics of the owners and employees were evident. Employees’ experiences varied according to where they worked. The findings suggest that similar and different processes occur in small firms compared to the large companies often studied in the literature. Like large firms, small firms are not neutral or based on a consensus. Small firm employees, however, may be considerably more vulnerable.
Elevated Platelet Count as Predictor of Recurrence in Rectal Cancer Patients Undergoing Preoperative Chemoradiotherapy Followed by Surgery
Authors: Toiyama Yuji , Inoue Yasuhiro , Kawamura Mikio , Kawamoto Aya , Okugawa Yoshinaga , Hiro Jyunichiro , Saigusa Susumu , Tanaka Koji , Mohri Yasuhiko , Kusunoki Masato
Published: February 2015

The impact of systemic inflammatory response (SIR) on prognostic and predictive outcome in rectal cancer after neoadjuvant chemoradiotherapy (CRT) has not been fully investigated. This retrospective study enrolled 89 patients with locally advanced rectal cancer who underwent neoadjuvant CRT and for whom platelet (PLT) counts and SIR status [neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR)] were available. Both clinical values of PLT and SIR status in rectal cancer patients were investigated. Elevated PLT, NLR, PLR, and pathologic TNM stage III [ypN(+)] were associated with significantly poor overall survival (OS). Elevated PLT, NLR, and ypN(+) were shown to independently predict OS. Elevated PLT and ypN(+) significantly predicted poor disease-free survival (DFS). Elevated PLT was identified as the only independent predictor of DFS. PLT counts are a promising pre-CRT biomarker for predicting recurrence and poor prognosis in rectal cancer.
A Review on the Safety of One-Stage Circumferential Ring Constriction Release
Authors: Prasetyono Theddeus O.H. , Sitorus Ade S.N.
Published: February 2015

The study was undertaken to investigate the use of one-stage circumferential ring-constriction release with Z-plasties regarding the safety, aesthetic appearance, and limb function. A thorough review was conducted on all English publications in PubMed during the period of 2001 through 2011. Titles and abstracts were identified using online search engine from National Library of Medicine's PubMed database under the keywords “limb constriction ring,” “limb constriction band,” “amniotic band,” “annular constriction,” and “circumferential constriction.” We used Boolean operator and field of title. Evaluation was done to search indications, timing of the first surgical intervention, time interval between surgeries, patients' gender, anatomic location of the ring, wound healing problems, and scar quality. Fourteen publications met the criteria. There were 17 patients with 25 ring constrictions in total. Sixteen ring constrictions (64%) were circumferential; nine (36%) were semi-circumferential. Mean age of 14 patients treated with one-stage release was 4.8 years. Six articles mentioned about normal development of postoperative limb function. Mean age of three patients treated with staged release was 10.5 months. Two articles mentioned regained distal muscle function postoperatively. It is confirmed that surgeons may continue the practice to release circumferential CRS in one stage.
Surgical Management of Perforated Gastrointestinal Posttransplantation Lymphoproliferative Disorder After Heart Transplantation
Authors: Osawa Hideki , Uemura Mamoru , Nishimura Junichi , Hata Taishi , Takemasa Ichiro , Mizushima Tsunekazu , Yamamoto Hirofumi , Doki Yuichiro , Mori Masaki
Published: February 2015

Posttransplantation lymphoproliferative disorder (PTLD) is a relatively rare and life-threatening complication after organ transplantation. From 1999 to 2012, 45 adult patients underwent heart transplantation at our hospital. Two of the patients developed PTLD after transplantation and required emergency surgery due to intestinal perforation. These cases were informative regarding the adequate surgical management of such cases. Both cases revealed Epstein-Barr virus-related PTLD. The optimal treatment of PTLD remains controversial, and PTLD with gastrointestinal perforation could be critical because the patients are already debilitated and immunocompromised after transplantation. Therefore, the nonspecific abdominal symptoms can be diagnostic for PTLD, and proper surgical intervention should be performed immediately. We present these two suggestive and rare cases in regard to the management of perforation with PTLD and a review of literature.
Impact of Glissonean Pedicle Approach for Centrally Located Hepatocellular Carcinoma in Mongolia
Authors: Chinburen Jigjidsuren , Gillet Michele , Yamamoto Masakazu , Enkh-Amgalan Tsiiregzen , Taivanbaatar Erdenebileg , Enkhbold Chinbold , Natsagnyam Puntsagdulam
Published: February 2015

Approaches to surgical resection of centrally located HCC remain controversial. Traditionally, hemi- or extended hepatectomy is suggested. However, it carries a high risk of postoperative complications in patients with cirrhosis. An alternative approach is Glissonean pedicle transection method. This study was conducted to assess the surgical and survival outcomes associated with central liver resection using the Glissonean pedicle transection. Sixty-nine patients with centrally located HCC were studied retrospectively. They were divided into conventional approach group with hemi- or extended hepatectomy, and Glissonean approach group with multisegmental central liver resection using the Glissonean pedicle transection. Glissonean pedicle transection method has comparable or superior surgical and survival outcomes to conventional hemi- or extended hepatectomy with regard to intraoperative bleeding, complications, hospital stay, and postoperative mortality and survival outcomes in patients with centrally located HCC. The 1-, 3-, and 5-year overall survival rates of the conventional approach group were 74%, 64%, and 55% respectively. For the Glissonean approach group, the 1 and 3-year overall survival rates were 86% and 61%, respectively. Glissonean pedicle transection method is a safe and effective surgical procedure in patients with centrally located HCC.
Preferential remineralization of dissolved organic phosphorus and non‐Redfield DOM dynamics in the global ocean: Impacts on marine productivity, nitrogen fixation, and carbon export
Authors: Letscher Robert T. , Moore J. Keith
Published: February 2015

Selective removal of nitrogen (N) and phosphorus (P) from the marine dissolved organic matter (DOM) pool has been reported in several regional studies. Because DOM is an important advective/mixing pathway of carbon (C) export from the ocean surface layer and its non‐Redfieldian stoichiometry would affect estimates of marine export production per unit N and P, we investigated the stoichiometry of marine DOM and its remineralization globally using a compiled DOM data set. Marine DOM is enriched in C and N compared to Redfield stoichiometry, averaging 317:39:1 and 810:48:1 for C:N:P within the degradable and total bulk pools, respectively. Dissolved organic phosphorus (DOP) is found to be preferentially remineralized about twice as rapidly with respect to the enriched C:N stoichiometry of marine DOM. Biogeochemical simulations with the Biogeochemical Elemental Cycling model using Redfield and variable DOM stoichiometry corroborate the need for non‐Redfield dynamics to match the observed DOM stoichiometry. From our model simulations, preferential DOP remineralization is found to increase the strength of the biological pump by ~9% versus the case of Redfield DOM cycling. Global net primary productivity increases ~10% including an increase in marine nitrogen fixation of ~26% when preferential DOP remineralization and direct utilization of DOP by phytoplankton are included. The largest increases in marine nitrogen fixation, net primary productivity, and carbon export are observed within the western subtropical gyres, suggesting the lateral transfer of P in the form of DOP from the productive eastern and poleward gyre margins may be important for sustaining these processes downstream in the subtropical gyres.
Seasonal changes of CO2, CH4, N2O, and SF6 in the upper troposphere/lower stratosphere over the Eurasian continent observed by commercial airliner
Authors: Sawa Yousuke , Machida Toshinobu , Matsueda Hidekazu , Niwa Yosuke , Tsuboi Kazuhiro , Murayama Shohei , Morimoto Shinji , Aoki Shuji
Published: February 2015

The seasonal variations of greenhouse gases at about 11 km altitude were analyzed from monthly air samples collected aboard a commercial airliner flying between Europe and Japan from April 2012 to March 2014. Compared to lower latitudes, the upper troposphere between 50 and 70°N showed higher CH4 and SF6 and an earlier seasonal phase of CO2. However, N2O values were similar to those in the subtropics. CH4, N2O, and SF6 in the lower stratosphere with potential temperature of up to 50 K above the tropopause showed seasonal variations with maxima in November/December and minima in April/May. At potential temperatures of 37.5–50 K above the tropopause, SF6 age was estimated to be about 22 months in May and 9 months in November. This strong seasonal variation is explained by the subsidence of high‐stratospheric air in spring and the effective flushing of the lowermost stratospheric air with tropospheric air in autumn.
On the azimuthal evolution and geoeffectiveness of the SIR‐associated stream interface
Authors: Kellerman A. C. , McPherron R. L. , Weygand J. M.
Published: February 2015

In this study, the azimuthal evolution of stream interaction regions is investigated, with the goal of predicting the time of arrival of an interface at some later position near 1 AU. A new stream interaction region (SIR) data set is constructed from ACE, STEREO A, and STEREO B in situ measurements, and it is demonstrated that the magnetic pressure and azimuthal flow angle provide the simplest robust estimation of the interface time. This data set was applied in the investigation. In the analysis, the geometric effects of the magnetic spiral angle and the tilt angle of stream interfaces are considered, and it is demonstrated how they may be used to improve forecasts of the arrival time of stream interaction regions from a spacecraft located at 1 AU. The polarity of the interplanetary magnetic field, toward or away from the Sun, observed by consecutive spacecraft measurements is considered for the slow and fast streams straddling a stream interface, in order to investigate whether the geoeffectiveness of the two streams may also be forecast from 1 AU. It is found that the polarity of the magnetic field, associated with a given stream interface, is conserved when observed by two separate spacecraft at azimuthal separations of 20° or less and while in the fast wind, however, the field polarity was not always conserved when observed in the slow wind ahead of the interface. An analysis of the tilt angle evolution during 2008 showed that while the azimuthal tilt angles were generally similar between observations in the same Carrington rotation and in consecutive rotations of the same corotating interaction region, the meridional tilt angles may differ significantly. The forecast analysis showed that the azimuthal evolution of a SIR at 1 AU may be predicted to within a day or two of the actual evolution time, while any discrepancy was most likely caused by changes at the coronal hole on the solar surface, leading azimuthal and radial evolution of the SIR.
An unusual sequence of sprites followed by a secondary TLE: An analysis of ELF radio measurements and optical observations
Authors: Mlynarczyk Janusz , Bór József , Kulak Andrzej , Popek Martin , Kubisz Jerzy
Published: February 2015

We present an extraordinary case of sprites in rapid succession—four sprite clusters in only 400 ms—followed by a secondary jet. Simultaneous ELF and optical observations, as well as lightning data, enabled us to thoroughly document this unique event. Locations of the transient luminous events (TLEs) were triangulated using video recordings from Nydek (Czech Republic) and Sopron (Hungary). We found that sprites were displaced up to 70 km from their parent lightning. The current moment waveform and charge moment changes associated with the event were reconstructed from the ELF electromagnetic signature recorded at the Hylaty station (Poland) by a new method. The results suggest that both a short‐delayed and a long‐delayed sprite were generated by a single positive cloud‐to‐ground discharge that had an intense continuing current. It had an unusual progression and lasted 200 ms. A large increase in the current moment during the development of a massive carrot sprite provides evidence in favor of sprite current. Our results also support the formation of an electric environment hypothesized to be necessary for the generation of the secondary TLEs.
Quasi‐static slip patch growth to 20 m on a geological fault inferred from acoustic emissions in a South African gold mine
Authors: Naoi Makoto , Nakatani Masao , Kgarume Thabang , Khambule Sifiso , Masakale Thabang , Ribeiro Luiz , Philipp Joachim , Horiuchi Shigeki , Otsuki Kenshiro , Miyakawa Koji , Watanabe Atsushi , Moriya Hirokazu , Murakami Osamu , Yabe Yasuo , Kawakata Hironori , Yoshimitsu Nana , Ward Anthony , Durrheim Raymond , Ogasawara Hiroshi
Published: February 2015

Three months of acoustic emission (AE) monitoring in a South African gold mine down to Mw −5 revealed a newly emergent planar cluster of 7557 events −3.9 ≤ Mw ≤ −1.8 (typical rupture radius of 6–70 cm) that expanded with time to reach a size of 20 m on a preexisting geological fault near an active mining front 1 km beneath the ground. It had a sharply defined, planar configuration, with hypocenters aggregated within a thickness of only several decimeters. We infer that the zone defines an aseismic slip patch on the fault, wherein the individual AEs represent failures of very small asperities being loaded by the aseismic slip. Additional support for the interpretation was obtained by analyzing composite focal mechanisms and repeating events. The patch expansion over 2 months was likely quasistatic because all individual AEs ruptured much smaller areas than the cluster size at the corresponding time. The b values dropped gradually from 2.6 to 1.4, consistent with a significant increase in shear stress expected of the mining style. Another cluster with similar characteristics emerged later on a neighboring part of the same fault and grew to a 10 m extent in the last weeks of the study period. The quasi‐static expansion of inferred localized slow‐slip patches to sizes of 10–20 m suggests that the critical crack length on natural faults can be at least as large, much exceeding the decimeter range derived from laboratory stick‐slip experiments on saw‐cut rocks.
An experimental study of the flow of gas along synthetic faults of varying orientation to the stress field: Implications for performance assessment of radioactive waste disposal
Authors: Cuss Robert J. , Harrington Jon F. , Noy David J. , Sathar Shanvas , Norris Simon
Published: February 2015

Critical stress theory states that fault transmissivity is strongly dependent upon orientation with respect to the stress tensor. This paper describes an experimental study aimed at verifying critical stress theory using a bespoke angled shear rig designed to examine the relationship between gas flows along a kaolinite‐filled synthetic fault as a function of fault dip. A total of 22 gas injection experiments were conducted on faults oriented 0°, 15°, 30°, and 45° to horizontal; both with and without active shear. Gas flow was seen to be complex; repeat gas injection testing showed a consistent gas entry pressure but considerably different, nonrepeatable, gas peak or breakthrough pressure. Gas flow occurred along discrete, dilatant pathways. The physics governing the pressure at which these features formed was repeatable; however, permeability was dependent on the number, distribution, and geometry of the resultant pathways. The nonrepeatable gas response suggests that the number of pathways was dependent on very subtle variations in gouge properties. No fault orientations were seen to exhibit nonflow characteristics, although critical stress theory predicted that two of the investigated fault angles should be effective seals. However, a small variation in gas entry pressure was seen with fault angle as a result of varying normal and shear stress acting on the gouge material. Shear was seen to enhance gas movement by reducing gas entry pressure and increased permeability once gas became mobile. Therefore, in kaolinite gouge‐filled faults, shear is not an effective self‐sealing mechanism to gas flow.
The influence of absorbed solar radiation by Saharan dust on hurricane genesis
Authors: Bretl Sebastian , Reutter Philipp , Raible Christoph C. , Ferrachat Sylvaine , Poberaj Christina Schnadt , Revell Laura E. , Lohmann Ulrike
Published: February 2015

To date, the radiative impact of dust and the Saharan air layer (SAL) on North Atlantic hurricane activity is not yet known. According to previous studies, dust stabilizes the atmosphere due to absorption of solar radiation but thus shifts convection to regions more conducive for hurricane genesis. Here we analyze differences in hurricane genesis and frequency from ensemble sensitivity simulations with radiatively active and inactive dust in the aerosol‐climate model ECHAM6‐HAM. We investigate dust burden and other hurricane‐related variables and determine their influence on disturbances which develop into hurricanes (developing disturbances, DDs) and those which do not (nondeveloping disturbances, NDDs). Dust and the SAL are found to potentially have both inhibiting and supporting influences on background conditions for hurricane genesis. A slight southward shift of DDs is determined when dust is active as well as a significant warming of the SAL, which leads to a strengthening of the vertical circulation associated with the SAL. The dust burden of DDs is smaller in active dust simulations compared to DDs in simulations with inactive dust, while NDDs contain more dust in active dust simulations. However, no significant influence of radiatively active dust on other variables in DDs and NDDs is found. Furthermore, no substantial change in the DD and NDD frequency due to the radiative effects of dust can be detected.
Context of ancient aqueous environments on Mars from in situ geologic mapping at Endeavour Crater
Authors: Crumpler L. S. , Arvidson R. E. , Bell J. , Clark B. C. , Cohen B. A. , Farrand W. H. , Gellert R. , Golombek M. , Grant J. A. , Guinness E. , Herkenhoff K. E. , Johnson J. R. , Jolliff B. , Ming D. W. , Mittlefehldt D. W. , Parker T. , Rice J. W. , Squyres S. W. , Sullivan R. , Yen A. S.
Published: February 2015

Using the Mars Exploration Rover Opportunity, we have compiled one of the first field geologic maps on Mars while traversing the Noachian terrain along the rim of the 22 km diameter Endeavour Crater (Latitude −2°16′33″, Longitude −5°10′51″). In situ mapping of the petrographic, elemental, structural, and stratigraphic characteristics of outcrops and rocks distinguishes four mappable bedrock lithologic units. Three of these rock units predate the surrounding Burns formation sulfate‐rich sandstones and one, the Matijevic Formation, represents conditions on early Mars predating the formation of Endeavour Crater. The stratigraphy assembled from these observations includes several geologic unconformities. The differences in lithologic units across these unconformities record changes in the character and intensity of the Martian aqueous environment over geologic time. Water circulated through fractures in the oldest rocks over periods long enough that texturally and elementally significant alteration occurred in fracture walls. These oldest pre‐Endeavour rocks and their network of mineralized and altered fractures were preserved by burial beneath impact ejecta and were subsequently exhumed and exposed. The alteration along joints in the oldest rocks and the mineralized veins and concentrations of trace metals in overlying lithologic units is direct evidence that copious volumes of mineralized and/or hydrothermal fluids circulated through the early Martian crust. The wide range in intensity of structural and chemical modification from outcrop to outcrop along the crater rim shows that the ejecta of large (>8 km in diameter) impact craters is complex. These results imply that geologic complexity is to be anticipated in other areas of Mars where cratering has been a fundamental process in the local and regional geology and mineralogy.
Capturing season‐specific precipitation signals in the northern Rocky Mountains, USA, using earlywood and latewood tree rings
Authors: Crawford Christopher J. , Griffin Daniel , Kipfmueller Kurt F.
Published: February 2015

Douglas‐fir (Pseudotsuga menziesii Mirb. Franco) total width, earlywood, and latewood tree ring chronologies were developed from six lower forest border sites in the northern Rocky Mountain region of central Idaho and southwestern Montana, USA, to assess the potential for season‐specific moisture reconstructions. These long‐lived arid‐site trees share strong between‐tree and between‐site coherence, and subannual tree ring chronologies reliably span the past seven centuries. Mapping spatiotemporal patterns in northern Rocky Mountain precipitation highlighted winter‐ and summer‐dominated precipitation regimes that transition along a west to east gradient. When Douglas‐fir tree rings were compared with instrumental climate records, season‐specific correlations emerged between earlywood and latewood. Total width, earlywood, and latewood shared the most statistically significant monthly correlations with April–June precipitation, whereas variability in adjusted latewood was tuned to June–August precipitation. Principal component analysis indicated that the leading mode of common variance for earlywood and adjusted latewood explained 65% and 55% variance in the chronologies, respectively. Pearson's correlations between earlywood principal component one and the northern Rocky Mountain precipitation field showed that annual (July–June) and spring (April–June) precipitation exhibited the strongest pattern of significance in central Idaho and southwestern Montana valleys and the Snake River Plain. Summer precipitation (June–August) was correlated with adjusted latewood principal component one and was particularly pronounced along and east of the continental divide in southwestern Montana. These results indicate that Douglas‐fir earlywood and adjusted latewood tree rings in the northern Rocky Mountains retain season‐specific precipitation signals and may be helpful for studying historical precipitation within the winter‐summer transition zone.
Changes in seismicity before and after the 2011 Tohoku earthquake around its southern limit revealed by dense ocean bottom seismic array data
Authors: Nakatani Yukihiro , Mochizuki Kimihiro , Shinohara Masanao , Yamada Tomoaki , Hino Ryota , Ito Yoshihiro , Murai Yoshio , Sato Toshinori
Published: February 2015

The southern limit of the 2011 Tohoku earthquake is considered to be located around off Ibaraki. However, it is not well constrained how far south the large slip extended. To give better constraints, we investigated seismicity including small earthquakes before and after the Tohoku earthquake around off Ibaraki using dense ocean bottom seismic array data. We automatically identified epicenters by backprojecting semblance values resulting in a considerable increase in the number of detected events compared with those listed in the catalog based on onshore observation. The results revealed a couple of seismicity‐activated region. The largest aftershock also occurred ~30 min after the main shock. Our detailed results suggest that this highly activated seismicity was initiated by the largest aftershock instead of the main shock. It, then, suggests that the large coseismic slip zone of the Tohoku earthquake may not have extended off Ibaraki.
In situ observations of EMIC waves in O+ band by the Van Allen Probe A
Authors: Yu Xiongdong , Yuan Zhigang , Wang Dedong , Li Haimeng , Huang Shiyong , Wang Zhenzhen , Zheng Qiao , Zhou Mingxia , Kletzing C. A. , Wygant J. R.
Published: February 2015

Through polarization and spectra analysis of the magnetic field observed by the Van Allen Probe A, we present two typical cases of O+ band electromagnetic ion cyclotron (EMIC) waves in the outer plasmasphere or plasma trough. Although such O+ band EMIC waves are rarely observed, 18 different events of O+ band EMIC waves (16 events in the outer plasmasphere and two events in the plasma trough) are found from September 2012 to August 2014 with observations of the Van Allen Probe A. We find that the preferred region for the occurrence of O+ band EMIC waves is in L = 2–5 and magnetic local time  = 03–13, 19–20, which is in accordance with the occurrence region of O+ ion torus. Therefore, our result suggests that the O+ ion torus in the outer plasmasphere during geomagnetic activities should play an important role in the generation of EMIC waves in O+ band.
Aggression can be contagious: Longitudinal associations between proactive aggression and reactive aggression among young twins
Authors: Dickson Daniel J. , Richmond Ashley D. , Brendgen Mara , Vitaro Frank , Laursen Brett , Dionne Ginette , Boivin Michel
Published: February 2015

The present study examined sibling influence over reactive and proactive aggression in a sample of 452 same‐sex twins (113 male dyads, 113 female dyads). Between and within siblings influence processes were examined as a function of relative levels of parental coercion and hostility to test the hypothesis that aggression contagion between twins occurs only among dyads who experience parental coerciveness. Teacher reports of reactive and proactive aggression were collected for each twin in kindergarten (M = 6.04 years; SD = 0.27) and in first grade (M = 7.08 years; SD = 0.27). Families were divided into relatively low, average, and relatively high parental coercion‐hostility groups on the basis of maternal reports collected when the children were 5 years old. In families with relatively high levels of parental coercion‐hostility, there was evidence of between‐sibling influence, such that one twin's reactive aggression at age 6 predicted increases in the other twin's reactive aggression from ages 6 to 7, and one twin's proactive aggression at age 6 predicted increases in the other twin's proactive aggression from ages 6 to 7. There was also evidence of within‐sibling influence such that a child's level of reactive aggression at age 6 predicted increases in the same child's proactive aggression at age 7, regardless of parental coercion‐hostility. The findings provide new information about the etiology of reactive and proactive aggression and individual differences in their developmental interplay. Aggr. Behav. 41:455–466, 2015. © 2015 Wiley Periodicals, Inc.
N‐Type Conjugated Polymer‐Enabled Selective Dispersion of Semiconducting Carbon Nanotubes for Flexible CMOS‐Like Circuits
Authors: Wang Huiliang , Li Yaoxuan , Jiménez‐Osés Gonzalo , Liu Peng , Fang Ya , Zhang Jie , Lai Ying‐Chih , Park Steve , Chen Liwei , Houk Kendall N. , Bao Zhenan
Published: February 2015

Sorting of semiconducting single‐walled carbon nanotubes (SWNTs) by conjugated polymers has attracted considerable attention recently because of its simplicity, high selectivity, and high yield. However, up to now, all the conjugated polymers used for SWNT sorting are electron‐donating (p‐type). Here, a high‐mobility electron‐accepting (n‐type) polymer poly([N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)) (P(NDI2OD‐T2)) is utilized for the sorting of high‐purity semiconducting SWNTs, as characterized by Raman spectroscopy, dielectric force spectroscopy and transistor measurements. In addition, the SWNTs sorted by P(NDI2OD‐T2) have larger diameters than poly(3‐dodecylthiophene) (P3DDT)‐sorted SWNTs. Molecular dynamics simulations in explicit toluene demonstrate distinct linear or helical wrapping geometry between P(NDI2OD‐T2) and different types of SWNTs, likely as a result of the strong interactions between the large aromatic core of the P(NDI2OD‐T2) backbone and the hexagon path of SWNTs. By using high‐mobility n‐type P(NDI2OD‐T2) as the sorting polymer, ambipolar SWNT transistors with better electron transport than that attained by P3DDT‐sorted SWNTs are achieved. As a result, flexible negated AND and negated OR logic circuits from the same set of ambipolar transistors are fabricated, without the need for doping. The use of n‐type polymers for sorting semiconducting SWNTs and achieving ambipolar SWNT transistor characteristics greatly simplifies the fabrication of flexible complementary metal‐oxide‐semiconductor‐like SWNT logic circuits.
Magnetosomes, Biogenic Magnetic Nanomaterials for Brain Molecular Imaging with 17.2 T MRI Scanner
Authors: Mériaux Sébastien , Boucher Marianne , Marty Benjamin , Lalatonne Yoann , Prévéral Sandra , Motte Laurence , Lefèvre Christopher T. , Geffroy Françoise , Lethimonnier Franck , Péan Michel , Garcia Daniel , Adryanczyk‐Perrier Géraldine , Pignol David , Ginet Nicolas
Published: February 2015

The fast development of sensitive molecular diagnostic tools is currently paving the way for a personalized medicine. A new class of ultrasensitive magnetic resonance imaging (MRI) T2‐contrast agents based on magnetosomes, magnetite nanocrystals biomineralized by magnetotactic bacteria, is proposed here. The contrast agents can be injected into the blood circulation and detected in the picomolar range. Purified magnetosomes are water‐dispersible and stable within physiological conditions and exhibit at 17.2 T a transverse relaxivity r2 four times higher than commercial ferumoxide. The subsequent gain in sensitivity by T2*‐weighted imaging at 17.2 T of the mouse brain vasculature is evidenced in vivo after tail vein injection of magnetosomes representing a low dose of iron (20 μmoliron kg−1), whereas no such phenomenon with the same dose of ferumoxide is observed. Preclinical studies of human pathologies in animal models will benefit from the combination of high magnetic field MRI with sensitive, low dose, easy‐to‐produce biocompatible contrast agents derived from bacterial magnetosomes.
Ferroelectricity and Antiferroelectricity of Doped Thin HfO2‐Based Films
Authors: Park Min Hyuk , Lee Young Hwan , Kim Han Joon , Kim Yu Jin , Moon Taehwan , Kim Keum Do , Müller Johannes , Kersch Alfred , Schroeder Uwe , Mikolajick Thomas , Hwang Cheol Seong
Published: February 2015

The recent progress in ferroelectricity and antiferroelectricity in HfO2‐based thin films is reported. Most ferroelectric thin film research focuses on perovskite structure materials, such as Pb(Zr,Ti)O3, BaTiO3, and SrBi2Ta2O9, which are considered to be feasible candidate materials for non‐volatile semiconductor memory devices. However, these conventional ferroelectrics suffer from various problems including poor Si‐compatibility, environmental issues related to Pb, large physical thickness, low resistance to hydrogen, and small bandgap. In 2011, ferroelectricity in Si‐doped HfO2 thin films was first reported. Various dopants, such as Si, Zr, Al, Y, Gd, Sr, and La can induce ferro­electricity or antiferroelectricity in thin HfO2 films. They have large remanent polarization of up to 45 μC cm−2, and their coercive field (≈1–2 MV cm−1) is larger than conventional ferroelectric films by approximately one order of magnitude. Furthermore, they can be extremely thin (<10 nm) and have a large bandgap (>5 eV). These differences are believed to overcome the barriers of conventional ferroelectrics in memory applications, including ferroelectric field‐effect‐transistors and three‐dimensional capacitors. Moreover, the coupling of electric and thermal properties of the antiferroelectric thin films is expected to be useful for various applications, including energy harvesting/storage, solid‐state‐cooling, and infrared sensors.
Role of Thick‐Lithium Fluoride Layer in Energy Level Alignment at Organic/Metal Interface: Unifying Effect on High Metallic Work Functions
Authors: Sun Zhengyi , Shi Shengwei , Bao Qinye , Liu Xianjie , Fahlman Mats
Published: February 2015

The function of ≈3‐nm thick lithium fluoride (LiF) buffer layers in combination with high work function metal contacts such as coinage metals and ferromagnetic metals for use in organic electronics and spintronics is investigated. The energy level alignment at the organic/LiF/metal interface is systematically studied using photoelectron spectroscopy and the integer charge transfer model. The thick‐LiF buffer layer is found to pin the Fermi level to ≈3.8 eV, regardless of the work function of the initial metal due to energy level bending in the LiF layer caused by depletion of defect states. At 3‐nm thickness, the LiF buffer layer provides full coverage, and the organic semiconductor adlayers are found to physisorb with the consequence that the energy level alignment at the organic/LiF interface follows the integer charge transfer model's predictions.
Photophysics of Point Defects in ZnO Nanoparticles
Authors: Choi Sumin , Phillips Matthew R. , Aharonovich Igor , Pornsuwan Soraya , Cowie Bruce C. C. , Ton‐That Cuong
Published: February 2015

Zinc oxide (ZnO) nanoparticles have recently been identified as a promising candidate for advanced nanophotonics applications and quantum technologies. This work reports the formation of luminescent point defects and describes their photophysical properties. In particular, it is shown using correlative photoluminescence, cathodoluminescence, electron paramagnetic resonance (EPR), and X‐ray absorption near‐edge spectroscopy that green luminescence at 2.48 eV and an EPR line at g = 2.00 belong to a surface oxygen vacancy () center, while a second green emission at 2.28 eV is associated with zinc vacancy (VZn) centers. It is established that radiative point defects can be excited in the visible that exhibits nanosecond lifetimes using both above bandgap and sub‐bandgap 405 and 532 nm excitation. This work provides important knowledge towards employment of point defects in ZnO in nanophotonics technologies.
Dual‐Confined Flexible Sulfur Cathodes Encapsulated in Nitrogen‐Doped Double‐Shelled Hollow Carbon Spheres and Wrapped with Graphene for Li–S Batteries
Authors: Zhou Guangmin , Zhao Yubao , Manthiram Arumugam
Published: February 2015

Batteries with high energy and power densities along with long cycle life and acceptable safety at an affordable cost are critical for large‐scale applications such as electric vehicles and smart grids, but is challenging. Lithium–sulfur (Li‐S) batteries are attractive in this regard due to their high energy density and the abundance of sulfur, but several hurdles such as poor cycle life and inferior sulfur utilization need to be overcome for them to be commercially viable. Li–S cells with high capacity and long cycle life with a dual‐confined flexible cathode configuration by encapsulating sulfur in nitrogen‐doped double‐shelled hollow carbon spheres followed by graphene wrapping are presented here. Sulfur/polysulfides are effectively immobilized in the cathode through physical confinement by the hollow spheres with porous shells and graphene wrapping as well as chemical binding between heteronitrogen atoms and polysulfides. This rationally designed free‐standing nanostructured sulfur cathode provides a well‐built 3D carbon conductive network without requiring binders, enabling a high initial discharge capacity of 1360 mA h g−1 at a current rate of C/5, excellent rate capability of 600 mA h g−1 at 2 C rate, and sustainable cycling stability for 200 cycles with nearly 100% Coulombic efficiency, suggesting its great promise for advanced Li–S batteries.
John M. Prausnitz: Bridging abstractions and realities
Authors: O'Connell John P.
Published: February 2015

This Founders Tribute issue honors John Prausnitz as an exceptional intellectual leader, scholar, and educator and summarizes his impact on chemical engineering. John's early vision of connecting fundamental molecular theory to practical thermodynamic applications with Molecular Thermodynamics was an essential element in our profession's paradigm shift from empiricism to engineering science. John's writings and lectures have transformed our core knowledge and guided its utilization into areas well outside traditional engineering bounds. Further, he has vigorously advocated for technology to be considered in the context of all of life and as a human enterprise. Finally, John's personal interactions across generations and disciplines have inspired the personal and professional development of a vast community of students, coworkers, and colleagues. In countless ways, John Prausnitz has influenced the contemporary foundation and functioning of chemical engineering and of realms beyond. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2675–2688, 2015
Modeling of a membrane reactor system for crude palm oil transesterification. Part II: Transport phenomena
Authors: Oh Pin Pin , Chong Mei Fong , Lau Harrison Lik Nang , Choo Yuen May , Chen Junghui
Published: February 2015

The mechanistic modeling of biodiesel production process in membrane reactor with the consideration of chemical reaction, phase equilibrium, and ultrafiltration is important for the membrane reactor design. In part II of this work, the chemical and phase equilibrium (CPE) model for crude palm oil transesterification reaction in the membrane reactor developed in part I is extended to an integration of CPE with modified Maxwell–Stefan model, which considers multicomponent mass transport phenomena of concentration polarization and intramembrane. A good fit of simulated permeate fluxes and apparent solute rejection to the experimental data shows that the model has a good prediction capability. Reversible fouling was found to be the major fouling and no pore plugging was observed. Simulation results verified that micelles were retained by the membrane at CPO:MEOH molar ratio of 1:24 and catalyst concentration of 0.5 wt %. However, phase inversion happened when catalyst concentration of 0.05 and 0.1 wt % were used. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1981–1996, 2015
Occupational burns treated in emergency departments
Authors: Reichard Audrey A. , Konda Srinivas , Jackson Larry L.
Published: February 2015

Background

Despite reported declines, occupational burn injuries remain a workplace safety concern. More severe burns may result in costly medical treatment and long‐term physical and psychological consequences.

Methods

We used the National Electronic Injury Surveillance System—Occupational Supplement to produce national estimates of burns treated in emergency departments (EDs). We analyzed data trends from 1999 to 2008 and provided detailed descriptions of 2008 data.

Results

From 1999 to 2008 there were 1,132,000 (95% CI: ±192,300) nonfatal occupational burns treated in EDs. Burn numbers and rates declined approximately 40% over the 10 years. In 2008, men and younger workers 15–24 years old had the highest rates. Scalds and thermal burns accounted for more than 60% of burns. Accommodation and food service, manufacturing, and construction industries had the largest number of burns.

Conclusions

Despite declining burn rates, emphasis is needed on reducing burn hazards to young food service workers and using job specific hazard analyses to prevent burns. Am. J. Ind. Med. 58:290–298, 2015. © 2015 Wiley Periodicals, Inc.
Psychosocial job factors and biological cardiovascular risk factors in Mexican workers
Authors: Garcia‐Rojas Isabel Judith , Choi BongKyoo , Krause Niklas
Published: February 2015

Background

Psychosocial job factors (PJF) have been implicated in the development of cardiovascular disease. The paucity of data from developing economies including Mexico hampers the development of worksite intervention efforts in those regions.

Methods

This cross‐sectional study of 2,330 Mexican workers assessed PJF (job strain [JS], social support [SS], and job insecurity [JI]) and biological cardiovascular disease risk factors [CVDRF] by questionnaire and on‐site physical examinations. Alternative formulations of the JS scales were developed based on factor analysis and literature review. Associations between both traditional and alternative job factor scales with CVDRF were examined in multiple regression models, adjusting for physical workload, and socio‐demographic factors.

Results

Alternative formulations of the job demand and control scales resulted in substantial changes in effect sizes or statistical significance when compared with the original scales. JS and JI showed hypothesized associations with most CVDRF, but they were inversely associated with diastolic blood pressure and some adiposity measures. SS was mainly protective against CVDRF.

Conclusion

Among Mexican workers, alternative PJF scales predicted health outcomes better than traditional scales, and psychosocial stressors were associated with most CVDRF. Am. J. Ind. Med. 58:331–351, 2015. © 2015 Wiley Periodicals, Inc.
Risk factors associated with Toxoplasma gondii infection in captive Sapajus spp
Authors: Ferreira D. R. A. , Ribeiro V. O. , Laroque P. O. , Wagner P. G. C. , Pinheiro Júnior J. W. , Silva J. C. R. , Dubey J. P. , Rêgo E. W. , Mota R. A.
Published: February 2015

The aim of this study was to identify risk factors associated with prevalence of Toxoplasma gondii infection in captive capuchin monkeys at a facility in the northeastern Brazil. Serum samples from 116 bearded capuchin (Sapajus libidinosus), nine blonde capuchin (Sapajus flavius), five black‐capped capuchin (Sapajus apella), and four capuchin monkeys (Sapajus spp.) were tested for T. gondii antibodies using the modified agglutination test (MAT, cut‐off ≥25); antibodies were found in 85.3% (99/116) of S. libidinosus, 55.6% (5/9) of S. flavius, 80.0% (4/5) of S. apella, and 75.0% (3/4) of S. spp. The risk factors associated with T. gondii seropositivity were ingestion of raw meat [OR = 4.13 (1.26; 13.50)] and old age [OR = 4.90 (1.70; 14.13)]. Results indicate a very high T. gondii seropositivity in these primate populations. To minimize exposure to T. gondii raw meat should not be fed to these animals. Am. J. Primatol. 77:558–562, 2015. © 2015 Wiley Periodicals, Inc.
Allometric scaling and locomotor function in the primate pelvis
Authors: Lewton Kristi L.
Published: February 2015

Identification of positional behavior adaptation in the pelvis of primates is complicated by possible confounding effects of body size and phylogeny. Previous work on primate pelvic allometry has focused primarily on sexual dimorphism and its relationship to obstetric constraints in species with large fetal size relative to maternal size. This study investigates patterns of pelvic scaling with a specific aim to understand how pelvic scaling relates to locomotor function. Patterns of scaling of nine pelvic dimensions were examined in a broad comparative sample of 40 species of primates, covering both haplorhines and strepsirrhines, while accounting for phylogenetic nonindependence. Phylogenetic reduced major axis regressions on pelvic scaling patterns suggest that primate‐wide patterns are reflected in haplorhine‐ and strepsirrhine‐specific analyses. Many measures scale isometrically with pelvis size, but notably, features of the ilium tend to scale allometrically. As predicted, ilium width and lower ilium cross‐sectional area scale with positive allometry, while lower iliac height scales with negative allometry. Further regression analyses by locomotor group suggest that these ilium measures, as well as pubic symphysis and ischium lengths, differ in their scaling patterns according to locomotor mode. These results suggest that scaling differences within primates, when present, are related to functional differences in locomotor behavior and mechanics. This study supports recent work that identifies adaptations to locomotor loading in the ilium and highlights the need for a better understanding of the relationship between pelvic structural mechanics and the mechanical requirements of primate locomotion. Am J Phys Anthropol 156:511–530, 2015. © 2015 Wiley Periodicals, Inc.
Declining tibial curvature parallels ∼6150 years of decreasing mobility in central european agriculturalists
Authors: Macintosh Alison A. , Davies Thomas G. , Pinhasi Ron , Stock Jay T.
Published: February 2015

Long bones respond to mechanical loading through functional adaptation in a suite of morphological characteristics that together ensure structural competence to in vivo loading. As such, adult bone structure is often used to make inferences about past behavior from archaeological remains. However, such biomechanical approaches often investigate change in just one aspect of morphology, typically cross‐sectional morphology or trabecular structure. The relationship between longitudinal bone curvature and mobility patterns is less well understood, particularly in the tibia, and it is unknown how tibial curvature and diaphyseal cross‐sectional geometry interact to meet the structural requirements of loading. This study examines tibial curvature and its relationship with diaphyseal cross‐sectional geometry (CSG) and body size in preindustrial Central Europeans spanning ∼6150 years following the introduction of agriculture in the region. Anteroposterior centroid displacement from the proximo‐distal longitudinal axis was quantified at nine diaphyseal section locations (collectively representative of diaphyseal curvature) in 216 tibial three‐dimensional laser scans. Results documented significant and corresponding temporal declines in midshaft centroid displacement and CSG properties. Significant correlations were found between mid‐diaphyseal centroid displacement and all mobility‐related CSG properties, while the relationship weakened toward the diaphyseal ends. No significant relationship was found between centroid displacement and body size variables with the exception of the most distal section location. Results support a relationship between tibial curvature and cross‐sectional geometry among prehistoric Central European agricultural populations, and suggest that changes in mechanical loading may have influenced a suite of morphological features related to bone adaptation in the lower limb. Am J Phys Anthropol 157:260–275, 2015. © 2015 Wiley Periodicals, Inc.