bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of telomere length and function in radiosensitive mouse and human cells in response to DNA-PKcs inhibition
Authors: Yasaei Hemad , Gozaly-Chianea Yaghoub , Slijepcevic Predrag
Published: March 2013

Background

Telomeres, the physical ends of chromosomes, play an important role in preserving genomic integrity. This protection is supported by telomere binding proteins collectively known as the shelterin complex. The shelterin complex protects chromosome ends by suppressing DNA damage response and acting as a regulator of telomere length maintenance by telomerase, an enzyme that elongates telomeres. Telomere dysfunction manifests in different forms including chromosomal end-to-end fusion, telomere shortening and p53-dependent apoptosis and/or senescence. An important shelterin-associated protein with critical role in telomere protection in human and mouse cells is the catalytic subunit of DNA-protein kinase (DNA-PKcs). DNA-PKcs deficiency in mouse cells results in elevated levels of spontaneous telomeric fusion, a marker of telomere dysfunction, but does not cause telomere length shortening. Similarly, inhibition of DNA-PKcs with chemical inhibitor, IC86621, prevents chromosomal end protection through mechanism reminiscent of dominant-negative reduction in DNA-PKcs activity.

Results

We demonstrate here that the IC86621 mediated inhibition of DNA-PKcs in two mouse lymphoma cell lines results not only in elevated frequencies of chromosome end-to-end fusions, but also accelerated telomere shortening in the presence of telomerase. Furthermore, we observed increased levels of spontaneous telomeric fusions in Artemis defective human primary fibroblasts in which DNA-PKcs was inhibited, but no significant changes in telomere length.

Conclusion

These results confirm that DNA-PKcs plays an active role in chromosome end protection in mouse and human cells. Furthermore, it appears that DNA-PKcs is also involved in telomere length regulation, independently of telomerase activity, in mouse lymphoma cells but not in human cells.
Diversity in sequence-dependent control of GRO chemokine mRNA half-life
Authors: Herjan Tomasz , Novotny Michael , Hamilton Thomas A
Published: March 2013

Regulation of GRO chemokine half-life is determined by multiple sequence regions that confer IL-1α -dependent and -independent instability via distinct RNA binding proteins.

Neutrophil trafficking to sites of injury or infection is regulated, in part, by the closely related GRO family of chemokines (CXCL1, -2, and -3). Expression of the GRO chemokine genes is known to be determined by transcriptional bursts in response to proinflammatory stimulation, but post-transcriptional mechanisms that regulate mRNA half-life are now recognized as important determinants. mRNA half-life is regulated via distinct sequence motifs and sequence-specific, RNA-binding proteins, whose function is subject to regulation by extracellular proinflammatory stimuli. Moreover, such mechanisms exhibit cell-type and stimulus dependency. We now present evidence that in nonmyeloid cells, GRO2 and GRO3 isoforms exhibit at least two patterns of mRNA instability that are distinguished by differential sensitivity to specific mRNA-destabilizing proteins and stimulus-mediated prolongation of mRNA half-life, respectively. Although the 3′ UTR regions of GRO2 and GRO3 mRNAs contain multiple AREs, GRO2 has eight AUUUA pentamers, whereas GRO3 has seven. These confer quantitative differences in half-life and show sensitivity for TTP and KSRP but not SF2/ASF. Moreover, these AUUUA determinants do not confer instability that can be modulated in response to IL-1α. In contrast, IL-1α-sensitive instability for GRO2 and GRO3 is conferred by sequences located proximal to the 3′ end of the 3′UTR that are independent of the AUUUA sequence motif. These regions are insensitive to TTP and KSRP but show reduced half-life mediated by SF2/ASF. These sequence-linked, post-transcriptional activities provide substantial mechanistic diversity in the control of GRO family chemokine gene expression.
Source-receiver, reverse-time imaging of dual-source, vector-acoustic seismic data
Authors: Vasconcelos Ivan
Published: March 2013

Novel technologies in seismic data acquisition allow for recording full vector-acoustic (VA) data: pointwise recordings of pressure and its multicomponent gradient, excited by pressure only as well as dipole/gradient sources. Building on recent connections between imaging and seismic interferometry, we present a wave-equation-based, nonlinear, reverse-time imaging approach that takes full advantage of dual-source multicomponent data. The method’s formulation relies on source-receiver scattering reciprocity, thus making proper use of VA fields in the wavefield extrapolation and imaging condition steps in a self-consistent manner. The VA imaging method is capable of simultaneously focusing energy from all in- and outgoing waves: The receiver-side up- and downgoing (receiver ghosts) fields are handled by the VA receiver extrapolation, whereas source-side in- and outgoing (source ghosts) arrivals are accounted for when combining dual-source data at the imaging condition. Additionally, VA imaging handles image amplitudes better than conventional reverse-time migration because it properly handles finite-aperture directivity directly from dual-source, 4C data. For nonlinear imaging, we provide a complete source-receiver framework that relies only on surface integrals, thus being computationally applicable to practical problems. The nonlinear image can be implicitly interpreted as a superposition of several nonlinear interactions between scattering components of data with those corresponding to the extrapolators (i.e., to the model). We demonstrate various features of the method using synthetic examples with complex subsurface features. The numerical results show, e.g., that the dual-source, VA image retrieves subsurface features with “super-resolution”, i.e., with resolution higher than the limits of Born imaging, but at the cost of introducing image artifacts not present in the linear image. Although the method does not require any deghosting as a preprocessing step, it can use separated up- and downgoing fields to generate independent subsurface images.
Bright light therapy for symptoms of anxiety and depression in focal epilepsy: randomised controlled trial
Authors: Baxendale Sallie , O'Sullivan John , Heaney Dominic
Published: March 2013

Background

Bright light therapy is an effective treatment for seasonal affective disorder and non-seasonal depression. Depression and anxiety are common psychiatric comorbidities in epilepsy.

Aims

To examine the efficacy of bright light therapy for symptoms of anxiety and depression in adults with focal epilepsy (trial registration at ClinicalTrials.gov: NCT01028456).

Method

We recruited 101 adults with medically intractable focal epilepsy. Participants completed the Hospital Anxiety and Depression Scale (HADS) at the beginning (T1) and end of a 12-week baseline period (T2) and again after 12 weeks of daily light therapy (T3), with 51 participants using a high-intensity light box and 50 using a low-intensity one. Seizure diaries were kept throughout the baseline and trial period.

Results

A total of 58 patients completed the trial. Anxiety and depression scores were significantly reduced following the light therapy at T3in both the high- and low-intensity groups.

Conclusions

Light therapy resulted in a significant reduction in symptoms of anxiety and depression but we did not find any differences between high- v. low-intensity treatment This may, therefore, be an effective treatment for symptoms of low mood in epilepsy at lower intensities than those typically used to treat seasonal affective disorder. Further work is needed to investigate this possibility with an adequate placebo condition.
Hypothyroidism Compromises Hypothalamic Leptin Signaling in Mice
Authors: Groba Claudia , Mayerl Steffen , van Mullem Alies A. , Visser Theo J. , Darras Veerle M. , Habenicht Andreas J. , Heuer Heike
Published: March 2013

The impact of thyroid hormone (TH) on metabolism and energy expenditure is well established, but the role of TH in regulating nutritional sensing, particularly in the central nervous system, is only poorly defined. Here, we studied the consequences of hypothyroidism on leptin production as well as leptin sensing in congenital hypothyroid TRH receptor 1 knockout (Trhr1 ko) mice and euthyroid control animals. Hypothyroid mice exhibited decreased circulating leptin levels due to a decrease in fat mass and reduced leptin expression in white adipose tissue. In neurons of the hypothalamic arcuate nucleus, hypothyroid mice showed increased leptin receptor Ob-R expression and decreased suppressor of cytokine signaling 3 transcript levels. In order to monitor putative changes in central leptin sensing, we generated hypothyroid and leptin-deficient animals by crossing hypothyroid Trhr1 ko mice with the leptin-deficient ob/ob mice. Hypothyroid Trhr1/ob double knockout mice showed a blunted response to leptin treatment with respect to body weight and food intake and exhibited a decreased activation of phospho-signal transducer and activator of transcription 3 as well as a up-regulation of suppressor of cytokine signaling 3 upon leptin treatment, particularly in the arcuate nucleus. These data indicate alterations in the intracellular processing of the leptin signal under hypothyroid conditions and thereby unravel a novel mode of action by which TH affects energy metabolism.
p-Aminosalicylic Acid Production by Enzymatic Kolbe–Schmitt Reaction Using Salicylic Acid Decarboxylases Improved through Site-Directed Mutagenesis
Authors: Ienaga Saori , Kosaka Sachiyo , Honda Yuki , Ishii Yoshitaka , Kirimura Kohtaro
Published: March 2013

A reversible salicylic acid decarboxylase (Sdc) catalyzes the carboxylation of m-aminophenol (m-AP) to p-aminosalicylic acid (PAS) as an antituberculous agent, through an enzymatic Kolbe–Schmitt reaction. To develop a high-yield PAS production system through such an enzymatic reaction, we generated Sdc mutants by site-directed mutagenesis and succeeded in generating several mutants showing increased carboxylation specific activities. Among them, a Y64T-F195Y-Sdc mutant showed a 12-fold higher carboxylation specific activity toward m-AP than wild-type Sdc. By the whole-cell reaction of recombinant Escherichia coli BL21(DE3) expressing the gene encoding Y64T-F195Y-Sdc, 70 mM PAS was produced from 100 mM m-AP within 2 h. This reaction time was shortened to one-twelfth that of the PAS production using E. coli BL21(DE3) expressing the gene encoding wild-type Sdc (24 h). Moreover, 140 mM PAS was produced from 200 mM m-AP within 9 h by the whole-cell reaction of recombinant E. coli BL21(DE3) expressing the gene encoding Y64T-F195Y-Sdc.
Synthesis and Properties of Partially Fluorinated Poly(arylene ether) Block Copolymers Containing Ammonium Groups as Anion Conductive Membranes
Authors: Ono Hideaki , Miyake Junpei , Bae Byungchan , Watanabe Masahiro , Miyatake Kenji
Published: March 2013

Synthesis and properties of aromatic block copolymers containing fluorinated phenylene and biphenylene groups and ammonium-substituted fluorene groups are reported. High-molecular-weight poly(arylene ether) block copolymers were prepared from the corresponding telechelic oligomers and were chloromethylated. Quaternization reaction of the chloromethylated precursors with trimethylamine provided the title ammonium-substituted block copolymers (QPE-bl-4). The QPE-bl-4 membrane with the highest ion-exchange capacity (IEC = 1.3 mequiv g−1) showed high hydroxide ion conductivity (45 mS cm−1) at 80 °C due to its phase-separated morphology with interconnected ion-transporting pathway. The accelerated stability test in aqueous KOH solution containing hydrazine revealed that the ammonium groups decomposed to certain extent while the polymer main chains were rather robust to maintain the self-supporting membranes.
Sequential Peptide Ligation by Combining the Cys–Pro Ester (CPE) and Thioester Methods and Its Application to the Synthesis of Histone H3 Containing a Trimethyl Lysine Residue
Authors: Kawakami Toru , Akai Yuichi , Fujimoto Hisao , Kita Chieko , Aoki Yuko , Konishi Takehiko , Waseda Masazumi , Takemura Lisa , Aimoto Saburo
Published: March 2013

A peptide thioester is a key building block for protein synthesis by a ligation method, such as the thioester method and native chemical ligation. Combining these ligation methods offers flexibility in the choice of the condensation sites in a sequential ligation strategy. We describe herein a novel strategy, in which native chemical ligation followed by the thioester method are utilized, based on the use of a peptide containing a Cys–Pro ester (CPE) autoactivating unit at the C-terminus as a peptide thioester precursor. This sequential ligation strategy was applied to the synthesis of histone H3, which consists of 135 amino acid residues and contains a trimethyl Lys9 residue.
Category Positioning and Store Choice: The Role of Destination Categories
Authors: Briesch Richard A. , Dillon William R. , Fox Edward J.
Published: March 2013

We focus on destination categories, so named because they have the greatest impact on where households choose to shop and, more generally, on how category positioning affects which store a household chooses. We propose a reduced-form model-based analytical approach to identify categories that fill the destination role. Our approach determines which categories are most important to shoppers' store choice decisions and helps determine in which categories the retailer provides superior value. In addition, our approach allows us to understand the impact of the retailer's long-run merchandising policy decisions on the value it provides. Previous store choice research considered the effects of pricing, assortment and other merchandising decisions at the store level but did not focus on the effect of specific categories on store choice. This focus leads us to formulate a model that can (1) measure and explain the differential impact that specific categories have on shoppers' store choice decisions and (2) measure the relative value of retailers' category offerings, partitioning that value into the component resulting from retailer merchandising and the component that is nonmerchandising related. The model form captures differences in category value across stores (i.e., the store's category positioning) by specifying a spatial model for the store choice and category incidence intercepts. Our spatial model recognizes that stores position their offering vis-à-vis the category ideal based on long-run category merchandising decisions and that not all categories have the same importance in store choice decisions. We explore these issues for five retailers in the Charlotte, North Carolina market. We find that (1) category impact on store choice is highly skewed; (2) although categories with higher sales generally have a higher impact on store choice decisions, there are exceptions; (3) impact on store choice decisions does not vary systematically by the type of category (e.g., perishable versus dry grocery); and (4) our measure of category impact on store choice, although correlated with the category development index between retailers, is superior in that it provides a basis for comparing category impact within a retailer and how relative category value, based on long-run merchandising decisions, attracts shoppers to a store.
What Happened to Long-Term Employment? The Role of Worker Power and Environmental Turbulence in Explaining Declines in Worker Tenure
Authors: Bidwell Matthew J.
Published: March 2013

Recent declines in the average length of time that U.S. workers spend with a given employer represent an important change in the nature of the employment relationship, yet it is one whose causes are poorly understood. I explore those causes using Current Population Survey data on the tenure of men aged 30–65, from the years 1979–2008.

I argue that long-term employment relationships primarily occur when workers pressure employers to close off employment from market competition, reducing the attractiveness of external mobility relative to internal opportunities and increasing employment security. I then explore how two changes in organizations’ environments—a decline in union strength and increased turbulence from changes in technology and globalization—might have affected workers’ ability to secure such closed employment relationships over the last 30 years.

My results support the argument that declines in tenure reflect the reduced power of workers to secure closed employment relationships. Recent declines in tenure have been concentrated in large organizations, and many of those declines are explained by controlling for the changing levels of industry unionization. I find little evidence that foreign competition or technological change affected mobility. The results are robust to measures of changing industry growth rates and within-industry reorganization. Supplementary analyses suggest that layoffs are associated with different industry pressures than tenure and that voluntary mobility may have played an important role in declines in tenure.
Formability and Microstructural Characterization of Sintered Powder Metallurgical Preforms of Dual-Phase Steel
Authors: Mahesh K. , Sankaran S. , Venugopal P.
Published: March 2013

In an attempt to improve mechanical properties of powder metallurgical (P/M) preforms of ferrite–pearlite steel, a ferrite–martensite dual-phase P/M steel was produced through intercritical annealing. In the present paper, the densification characteristics and formability of sintered preforms of dual-phase P/M steel and its comparison with preforms of ferrite–pearlite P/M steel are presented. The elemental powders of required composition were thoroughly mixed and steel compacts with different preform densities were produced by applying recommended pressures. The sintered preform consisted of ferrite–pearlite microstructure whereas intercritically annealed preform contained fine martensite distributed in ferrite matrix. The variation in porosity for different preform densities was approximately in the range of 5 %–28 % for both the steels. Stage wise upsetting was performed to obtain the densification curves, and compression tests were carried out to estimate the apparent strength coefficient (Ka) and apparent strain-hardening exponent (na), to generate the forming limit diagram (FLD) for both the steels. With increasing mean preform density, the Ka values were increasing, whereas the na values were decreasing for both sintered and dual-phase steels. In FLD, the transition of Ka and na values was at critical transition density (CTD) of 6.43 g/cm3 and 6.15 g/cm3 for sintered and dual-phase steel, respectively. Thus, an increase of 4.5 % of safe zone limit in FLD was observed in dual-phase steel, which facilitates the selection of lower preform density for forming process. Interestingly, the contiguity ratio of the martensite phase was increasing with increase in the mean preform density, which changes significantly after CTD of 6.15 g/cm3 in dual-phase P/M steel.
Development and Characterization of Microstructure and Mechanical Properties of Heat-Treated Zr–2.5Nb Alloy for AHWR Pressure Tubes
Authors: Singh R. N. , Bind A. K. , Singh J. B. , Chakravartty J. K. , Thomas Paul V. , Madhusoodnan K. , Suwas Satyam , Saroja S. , Suri A. K. , Banerjee S.
Published: March 2013

Zr–2.5Nb Alloy is used in a cold-worked and stress-relieved (CWSR) condition as pressure tubes in Indian pressurized heavy water reactors (IPHWR). The life-limiting factor for pressure tubes is in-reactor dimensional changes caused by irradiation growth and creep resulting in diametral expansion and axial elongation. Recent work has indicated that heat-treated Zr–2.5Nb alloy may exhibit lower in-reactor dimensional changes vis-à-vis CWSR pressure tubes. The advanced heavy water reactor (AHWR) specification demands more stringent operating condition for the pressure tubes and it was decided to develop a new fabrication route for heat-treated Zr–2.5Nb alloy for possible application as pressure tubes in AHWR. In this work, the microstructural characterization and tensile properties evaluation was carried out using samples obtained from various stage of fabrication of water-quenched and aged Zr–2.5Nb alloy following a route similar to Fugen pressure tubes is discussed. The microstructure was characterized using optical and transmission electron microscopy. The chemical composition, morphology, and location of the precipitates formed during aging were studied using thin-foil electron microscopy and carbon extraction replica. Samples with its axes parallel to longitudinal (L) or transverse (T) direction of rolled plate were machined from quenched, cold-rolled, and aged material and were tested in tension at 25°C and 300°C. The microstructure and the tensile strength of the alloy processed in the present investigation were comparable to that of heat-treated pressure tubes used in Reaktor Bolshoy Moshchnosti Kanalniy (RBMK) and Fugen reactors.
Surface Modifications of Li-Ion Battery Electrodes with Ultrathin Amphoteric Oxide Coatings for Enhanced Elevated-Temperature Cycleability
Authors: Zhao Jianqing , Wang Ying
Published: March 2013

To enhance cycleability of LiMn2O4 at elevated-temperature we use atomic layer deposition (ALD) method to deposit a variety of ultrathin and highly conformal amphoteric oxide (ZnO, ZrO2, Al2O3) coatings for surface modification of LiMn2O4 electrodes. High-resolution transmission electron microscopic (HRTEM) images of ZnO, ZrO2 and Al2O3 ALD coated LiMn2O4 particles demonstrate the high qualities of ALD coatings with respect to remarkable conformity, homogeneity and uniformity. Two types of ALD-modified LiMn2O4 electrodes are fabricated: one is ALD-coated LiMn2O4 composite electrode, the other is electrode composed of ALD-coated LiMn2O4 particles and uncoated carbon/poly-vinylidenefluoride (PVDF) network. All LiMn2O4 electrodes modified with 6 oxide ALD layers (as thin as ∼1 nm) reveal significantly enhanced electrochemical performances than bare electrodes at both 25°C and 55°C. After 100 electrochemical cycles at 1 C at 55°C, the electrode consisting of LiMn2O4 particles coated with 6 ZnO ALD layers remains the highest capacity of 56.1 mAh/g, higher than 51.1 mAh/g of ZrO2 coated LiMn2O4 particles, 45.8 mAh/g of Al2O3 coated LiMn2O4 particles and 27.0 mAh/g of the bare composite electrode as well as 44.5 mAh/g of the composite electrode coated with 6 ZnO ALD layers. These results indicate that ZnO ALD coating is the most effective protective film for improved cycling stability, followed by ZrO2 and Al2O3. It is also found that amphoteric oxide coating on LiMn2O4 particles is more effective to enhance the cycleability of LiMn2O4 than coating on composite electrode. Furthermore, for coating either on composite electrode or on LiMn2O4 particles, the effect of ALD coating on improving capacity retention and increasing specific capacity of LiMn2O4 is more phenomenal at elevated temperature than at room temperature.
Fabrication of silicon nanowires by ion beam irradiation
Authors: Song J. , Dang Z. Y. , Azimi S. , Breese M. B. H.
Published: March 2013

Silicon nanowires are becoming more important because of increasing requirements of the small scale and dense integration of devices. We report a top-down fabrication method for silicon nanowires using high-energy ion beam irradiation of bulk p-type silicon followed by electrochemical etching. Silicon nanowires with a diameter of ∼50nm have been fabricated and densely patterned nanowire arrays fabricated in different resistivity silicon wafers. With a suitable support structure, free standing silicon nanowires are also achieved. We investigate results depending on silicon wafer resistivity and location within the irradiated area.
Recombination Lifetime in Microcrystalline Silicon Absorbers of Highly Efficient Thin-Film Solar Cells
Authors: Brammer Torsten , Stiebig Helmut
Published: March 2013

Absorber layers of microcrystalline silicon thin-film solar cells deposited by plasma-enhanced chemical vapor deposition are characterized regarding the recombination lifetime. The characterization is based on a comparison of experimentally determined solar cell characteristics with results from numerical device simulations. Evaluation of the dark reverse saturation current indicates a strong dependence of τ on the hydrogen dilution during the deposition. Close to the transition region to amorphous growth where the highest solar cell efficiencies are observed τ is maximum within the crystalline deposition regime and equals 30 ns.
Engaging stakeholders through participatory modelling
Authors: Garrod Guy , Raley Marian , Aznar Olivier , Espinosa Omar Bacqueiro , Barreteau Olivier , Gomez Myriam , Schaft Franziska , Turpin Nadine
Published: March 2013

Engaging relevant stakeholders in the planning process can generate better mutual understanding among participants and lead to decisions that are more sustainable. This study examines the potential for stakeholders to participate with modellers in the construction of development scenarios that can be explored through microsimulation modelling approaches. This activity requires participants, who are drawn from local administrations and the communities that they serve, to engage with the model at different stages of its development. Such engagement is important for model design and for ensuring that the resulting models are able to frame questions that the stakeholders are interested in. This study adopted a participatory workshop approach across three European countries to explore the potential for stakeholders to engage with modellers at different stages of the modelling process. The interactions between modellers and local stakeholders provided a number of important insights on the future design, conduct and application of such exercises and suggest some limits to the use of scenario development as a tool for participatory modelling and sustainable development.
Briefing: Participation, consensus and adjudication in designing the A3 Hindhead tunnel, UK
Authors: Stafford Jenny
Published: March 2013

The successful development of the A3 Hindhead tunnel under the Devil's Punch Bowl in Surrey, UK has been recognised for its engineering excellence as well as through the high level of support for the project locally in recent years. The scheme was over 20 years in the making but the 10 years prior to the opening of the 6·5 km bypass and tunnel in 2011 saw an approach to design and delivery that consistently managed to overcome potential pitfalls. One of the principal determinants of the project's successful route to completion was the strength and effectiveness of the stakeholder and public involvement during the planning and design of the scheme. One of the proposed junctions for the original bypass design was removed from the scheme following consultation. Local recreation user groups were involved in influencing the design of mitigation measures that have greatly improved access and enjoyment of the Devil's Punch Bowl, a renowned natural landmark and designated Site of Special Scientific Interest. However, the participation processes were not seamless; at Public Inquiry the requests from cyclists and some local residents to retain the old A3 were resisted and effectively arbitration between the different recreational stakeholders occurred.
Relative density concept is not a reliable criterion
Authors: Hamidi Babak , Varaksin Serge , Nikraz Hamid
Published: March 2013

Many years ago, a new concept called relative density was developed with the intention of appropriately defining the looseness and denseness of sand or sand–gravel soils in a meaningful way. Soon after, relative density found its way into ground improvement as an acceptance criterion by engineers who were more familiar with the construction of engineered backfilling rather than thick mass treatment. There are considerable amounts of research and publications that are able to well demonstrate the unreliability of relative density as an acceptance criterion. Relative density has no real influence on the soil's performance, its range of application does not span across all soil types, and it is subject to large inherent errors that make its use a technical risk. Here, the reasons why the concept of relative density is unreliable and should not be used for a ground improvement acceptance criterion are presented and discussed.
Remediation against floatation of underground structures
Authors: Chian Siau Chen , Madabhushi Santana Phani Gopal
Published: March 2013

Underground structures located in liquefiable soil deposits are susceptible to floatation following an earthquake event due to their lower unit weight relative to the surrounding saturated soil. Centrifuge tests have been carried out to assess the effectiveness of existing remediation techniques in reducing the uplift of underground structures, namely in situ densification and the use of coarse sand backfill. The centrifuge test results showed that these methods do reduce the uplift displacement of buoyant structures. Their performance was thereafter linked to the theoretical mechanism of floatation of underground structures. Based on the understanding from preceding tests, a further improvement on the use of the coarse sand backfill was carried out, which produced a greater reduction in the uplift displacement of the structure. Each of these techniques, however, does pose issues when applied in the field, such as possible damage to surrounding structures, construction issues and maintenance problems.
Factors that influence safety culture in construction
Authors: Wamuziri Sam
Published: March 2013

Although there is no consensus on how to define the safety culture of an organisation, the concept is now recognised as an essential contributor to improved occupational safety performance in construction. Indeed, the subject of safety culture has attracted considerable attention in the literature in recent years. The health and safety culture in an organisation is determined by the social and psychological relationships in the workplace. Some view safety culture as a management issue but so fuzzy to the extent that it cannot be measured or reliably changed. This paper aims to explore and to make explicit some of the key factors that influence safety culture in construction. The concepts of organisational culture and climate are firstly discussed. The concept of health and safety culture is then evaluated including the factors that influence it; its assessment and measurement methods. The results of interviews with site safety managers of construction companies that exhibit strong safety cultures are reported. The objective of this work was to determine what works for them. The results reveal that the factors that contribute to positive and negative safety cultures in construction can be grouped into six categories: organisation factors, individual factors, team factors, job design factors, management factors and supervisory factors.
Fuel economy of urban road networks based on traffic flow
Authors: Feng Yu-qin , Leng Jun-qiang , Zhang Ya-ping , He Yi
Published: March 2013

The fuel economy of road segments depends mainly on traffic flow saturation, and the economical saturation is about 0·4. The fuel economy of intersections is closely related to split and saturation, and the economical saturation is about 0·2–0·3. Fuel economy models were established with road segments and intersections as elementary units; fuel consumption and traffic flow data collected in the field were used to perform model calibration. A break with the traditional idea that route fuel economy modelling was set by general series systems was made by considering the route as a whole unit instead of using a paralleling system; another break was made to calculate the weighted average fuel economy of origin–destination pairs. On the basis of origin–destination fuel economy, the road network fuel economy model was set up. Ultimately, a partial road network was selected for analysis of the network fuel economy and to verify the correctness and reasonableness of the models.
Yield and Bread‐Making Potential of Spring Wheat Under Mineral and Organic Fertilization
Authors: Rieux Christine M. , Vanasse Anne , Chantigny Martin H. , Gélinas Pierre , Angers Denis A. , Rochette Philippe , Royer Isabelle
Published: March 2013

The food industry is increasingly interested in bread wheat (Triticum aestivum L.) produced under low‐input farming. However, the influence of soil management practices and N source type on wheat is unclear. Spring wheat (‘AC Brio’) was grown in 2009 and 2010 near Quebec City, QC, Canada, on a silty clay (SC) and a sandy loam (SL) soil under cool and wet climatic conditions. Nitrogen treatments comprised a control (mineral fertilizer containing P and K only [PK]), a complete mineral fertilizer (NPK), and three organic N sources (liquid swine manure [LSM], liquid dairy cattle manure [LCM], and solid poultry manure [SPM]) applied in the spring to moldboard plowed and minimum till plots. Even though some differences were found in crop N uptake between soil types and production years, the average amount of grains produced at harvest per unit of N applied was greater with NPK (8.5 kg grain kg−1 N applied) than with animal manures but was similar among LSM (6.4), SPM (5.8), and LCM (5.0). The use of LSM and SPM resulted in grain yields similar to those obtained with NPK. The grain protein and gluten content were generally greater with NPK (150 g protein kg−1 and 105 g gluten kg−1) than with the organic N sources (142 to 144 g protein kg−1 and 94 to 100 g gluten kg−1). However, these disparities had no effect on bread loaf volumes (average of 790 mL). The use of animal manures appears as an interesting alternative to mineral N fertilizers to produce good quality bread‐making wheat.
Inheritance of Resistance to the New Race of Powdery Mildew in Watermelon
Authors: Tetteh Antonia Y. , Wehner Todd C. , Davis Angela R.
Published: March 2013

Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] production in the United States has, in the past few years, incurred significant losses to races 1W and 2WU.S. powdery mildew (Podosphaera xanthii) infection. We report the mode of inheritance, gene action, and heritability of race 2WU.S. resistance in two populations derived from a cross involving the resistant genotype PI 189225 and the susceptible ‘Charleston Gray’ and PI 269677. Parents, F1, F2, BC1P1, and BC1P2 plants were inoculated and evaluated for leaf and stem resistance in two replicated greenhouse experiments. Segregation patterns revealed that only leaf resistance rating in Charleston Gray × PI 189225 fit the model for single gene inheritance. Generation mean analysis established only additive gene action for leaf resistance while for stem resistance, additive, dominance, and epistatic effects were important. Narrow‐sense heritability estimates were higher for stem (0.81) than for leaf (0.58) resistance. Lack of dominance and epistatic effects combined with high heritability indicated high probability of success in selecting for leaf resistance in early generations. Stem resistance had a higher additive effect, lower dominance, and moderate heritability, but progress toward resistance should be possible. In population PI 269677 × PI 189225, epistatic effects combined with low heritability (0.20) and presence of duplicate epistasis may result in slower progress from selection.
Prediction of Water Retention of Soils from the Humid Tropics by the Nonparametric k‐Nearest Neighbor Approach
Authors: Botula Yves-Dady , Nemes Attila , Mafuka Paul , Van Ranst Eric , Cornelis Wim M.
Published: March 2013

Nonparametric approaches such as the k‐nearest neighbor (k‐NN) approach are considered attractive for pedotransfer modeling in hydrology; however, they have not been applied to predict water retention of highly weathered soils in the humid tropics. Therefore, the objectives of this study were: to apply the k‐NN approach to predict soil water retention in a humid tropical region; to test its ability to predict soil water content at eight different matric potentials; to test the benefit of using more input attributes than most previous studies and their combinations; to discuss the importance of particular input attributes in the prediction of soil water retention at low, intermediate, and high matric potentials; and to compare this approach with two published tropical pedotransfer functions (PTFs) based on multiple linear regression (MLR). The overall estimation error ranges generated by the k‐NN approach were statistically different but comparable to the two examined MLR PTFs. When the best combination of input variables (sand + silt + clay + bulk density + cation exchange capacity) was used, the overall error was remarkably low: 0.0360 to 0.0390 m3 m−3 in the dry and very wet ranges and 0.0490 to 0.0510 m3 m−3 in the intermediate range (i.e., −3 to −50 kPa) of the soil water retention curve. This k‐NN variant can be considered as a competitive alternative to more classical, equation‐based PTFs due to the accuracy of the water retention estimation and, as an added benefit, its flexibility to incorporate new data without the need to redevelop new equations. This is highly beneficial in developing countries where soil databases for agricultural planning are at present sparse, though slowly developing.
Sulfamethazine Transport in Agroforestry and Cropland Soils
Authors: Chu Bei , Anderson Stephen H. , Goyne Keith W. , Lin Chung-Ho , Lerch Robert N.
Published: March 2013

Knowledge of veterinary antibiotic (VA) transport and persistence is critical to understanding environmental risks associated with these potential contaminants. To understand mobility of sulfamethazine (SMZ) and sorption processes involved during SMZ transport in soil, batch sorption experiments were conducted and column leaching experiments were performed with repacked soil columns containing silt loam soils collected from cropland (Crop) and an agroforestry (AGF) vegetative buffer system. Bromide (Br−) was applied as a nonreactive tracer to characterize the flow of water. Radio‐labeled (14C) SMZ with or without 150 mg L−1 of manure‐derived dissolved organic carbon (DOC), was added as a pulse and leaching of the compounds was monitored for 21 d. Sulfamethazine concentration in the leachate was monitored using a liquid scintillation counter and high performance liquid chromatography analysis confirmed absence of SMZ degradation product in the leachate. Breakthrough curves of SMZ and Br− were constructed for each column. Bromide breakthrough curves were fitted with a convection/dispersion based transport equilibrium model with no sorption, whereas SMZ breakthrough curves were fitted with multisite sorption chemical nonequilibrium transport models with linear or Freundlich sorption components. Results indicated that the three‐site model containing two reversible sites (one instantaneous and one kinetic) and one irreversible site coupled with the Freundlich sorption component (3S2R‐Freu‐irrev model) best described SMZ transport through the columns with model efficiencies of 0.998, 0.994, and 0.991 for AGF, AGF + DOC and Crop soils, respectively. No difference or small difference between fitted sorption parameters, such as the linear sorption coefficient (Kd), Freundlich sorption coefficient (Kf), and Freundlich nonlinearity parameter (N), and those obtained from equilibrium sorption experiments was observed. Data from equilibrium sorption experiments and column transport experiments suggested that the AGF soil was able to retain a larger quantity of SMZ than the Crop soil, and DOC had little effect on SMZ sorption or leaching. Greater SMZ retention by the AGF soil compared to the Crop soil suggests that vegetative buffers may be a viable means to mitigate VA loss from agroecosystems.
Soil Permittivity Response to Bulk Electrical Conductivity for Selected Soil Water Sensors
Authors: Schwartz R. C. , Casanova J.J. , Pelletier M.G. , Evett S.R. , Baumhardt R.L.
Published: March 2013

Bulk electrical conductivity (σa) can dominate the low frequency dielectric loss spectrum in soils, causing changes in the permittivity and errors in estimated water content. We examined the dependence of measured apparent permittivity (Ka) on σa in contrasting soils using time‐domain reflectometry (TDR), a digital time‐domain transmission (TDT) sensor, and a capacitance sensor (5TE) during near saturated solute displacement experiments. Sensors were installed in columns packed with fine sand or a clay loam soil. Displacement experiments were completed by first equilibrating columns with 0.25 dS m−1 CaCl2, introducing a step pulse of ∼4.7 dS m−1 CaCl2 and, after equilibration, displacing the resident solution with 0.25 dS m−1 CaCl2. Using TDR, measured Ka increased with increasing σa; however, the slope of this response averaged 3.47 m dS−1 for clay loam compared with 0.19 m dS−1 for sand. The large response in the clay loam was attributed to relaxation losses that narrowed the effective bandwidth from 821 to an estimated 164 MHz. In contrast, the effective frequency in sand averaged 515 MHz. Permittivity measured using the TDT probe exhibited little or no sensitivity to σa (<0.32 m dS−1) in both media. Measured Ka using the 5TE probe declined with increasing σa up to 1 to 1.8 dS m−1 and then increased thereafter with net negative responses for sand (ΔKa/Δσa = −3.1 m dS−1) and net positive responses for the clay loam (ΔKa/Δσa = 2.9 m dS−1). Consideration of the Ka–σa response is required for accurate soil water content estimation (±0.03 m3 m−3) in the presence of solution EC variations using TDR in fine‐textured soils or the 5TE sensor in all media. Large differences in the sampling volumes between 5TE‐measured bulk EC and permittivity confounded the Ka–σa response in the presence of a concentration gradient.
Characterizing Coarse‐Scale Representativeness of in situ Soil Moisture Measurements from the International Soil Moisture Network
Authors: Gruber A. , Dorigo W.A. , Zwieback S. , Xaver A. , Wagner W.
Published: March 2013

In situ soil moisture measurements play a key role for a variety of large‐scale applications. A deep understanding of their quality, especially in terms of spatial representativeness, is crucial for reliably using them as reference data. This study assesses random errors in the coarse‐scale representation of in situ soil moisture measurements from more than 1400 globally distributed stations, drawn from the International Soil Moisture Network (ISMN), using the triple collocation method. The method was applied on the original measurements as well as on soil moisture anomalies. Error estimates were summarized for different networks, depths, and measurement principles and furthermore related to the respective climate class, soil type, average soil moisture condition, and soil moisture variability to find possible relationships between measurement errors and local properties. The average network error varies from about 0.02 to 0.06 m3m−3with generally increasing error variability with increasing average error. Trends of (i) decreasing errors with increasing measurement depth and of (ii) increasing errors with increasing average soil moisture conditions and soil moisture variability were found for most networks and sensor types. The errors when looking into anomalies are in general lower than for absolute values. No statistically reliable trends for climate‐ and soil texture classes were found. These results highlighted the necessity of developing a comprehensive quality control process for in situ measurements to reliably exploit existing data sets and to select representative sites and sensors most appropriate for the requirements of a particular larger‐scale application.
Modifiable Patient Characteristics and Racial Disparities in Evaluation Completion and Living Donor Transplant
Authors: Waterman Amy D. , Peipert John D. , Hyland Shelley S. , McCabe Melanie S. , Schenk Emily A. , Liu Jingxia
Published: March 2013

Background and objectives

To reduce racial disparities in transplant, modifiable patient characteristics associated with completion of transplant evaluation and receipt of living donor kidney transplant must be identified.

Design, setting, participants, & measurements

From 2004 to 2007, 695 black and white patients were surveyed about 15 less-modifiable and 10 more-modifiable characteristics at evaluation onset; whether they had completed evaluation within 1 year and received living donor kidney transplants by 2010 was determined. Logistic regression and competing risks time-to-event analysis were conducted to determine the variables that predicted evaluation completion and living donor kidney transplant receipt.

Results

Not adjusting for covariates, blacks were less likely than whites to complete evaluation (26.2% versus 51.8%, P<0.001) and receive living donor kidney transplants (8.7% versus 21.9%, P<0.001). More-modifiable variables associated with completing evaluation included more willing to be on the waiting list (odds ratio=3.4, 95% confidence interval=2.1, 5.7), more willing to pursue living donor kidney transplant (odds ratio=2.7, 95% confidence interval=1.8, 4.0), having access to more transplant education resources (odds ratio=2.2, 95% confidence interval=1.5, 3.2), and having greater transplant knowledge (odds ratio=1.8, 95% confidence interval=1.2, 2.7). Patients who started evaluation more willing to pursue living donor kidney transplant (hazard ratio=4.3, 95% confidence interval=2.7, 6.8) and having greater transplant knowledge (hazard ratio=1.2, 95% confidence interval=1.1, 1.3) were more likely to receive living donor kidney transplants.

Conclusions

Because patients who began transplant evaluation with greater transplant knowledge and motivation were ultimately more successful at receiving transplants years later, behavioral and educational interventions may be very successful strategies to reduce or overcome racial disparities in transplant.
Sodium Thiosulfate Therapy for Calcific Uremic Arteriolopathy
Authors: Nigwekar Sagar U. , Brunelli Steven M. , Meade Debra , Wang Weiling , Hymes Jeffrey , Lacson Eduardo
Published: March 2013

Background and objective

Calcific uremic arteriolopathy (CUA) is an often fatal condition with no effective treatment. Multiple case reports and case series have described intravenous sodium thiosulfate (STS) administration in CUA, but no studies have systematically evaluated this treatment.

Design, setting, participants, & measurements

This study included 172 patients undergoing maintenance hemodialysis who had CUA and were treated with STS between August 2006 and June 2009 at Fresenius Medical Care North America. Of these, 85% completed STS therapy. Clinical, laboratory, and mortality data were abstracted from clinical information systems. Responses to survey questionnaires sent to treating physicians regarding patient-level outcomes were available for 53 patients. Effect on CUA lesions and mortality were summarized as CUA outcomes. Relevant laboratory measures, weight (using pairwise comparisons of values before, during, and after STS), and adverse events were summarized as safety parameters.

Results

Mean age of the cohort was 55 years, and 74% of patients were women. Median STS dose was 25 g, and median number of doses was 38. Among surveyed patients, CUA completely resolved in 26.4%, markedly improved in 18.9%, improved in 28.3%, and did not improve in 5.7%; in the remaining patients (20.8%), the response was unknown. One-year mortality in patients treated with STS was 35%. Adverse events, laboratory abnormalities, and weight-related changes were mild. Significant reductions in serum phosphorous (P=0.02) and parathyroid hormone (P=0.01) were noted during STS treatment in patients who completed the therapy.

Conclusions

Although conclusive evidence regarding its efficacy is lacking, a majority of patients who received STS demonstrated clinical improvement in this study.