bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of L‐Altrose and Some Derivatives
Authors: Lunau Nathalie , Meier Chris
Published: September 2012

A convenient approach to the chemical synthesis of L‐altrose (1) and its 6‐deoxy derivative 2 has been developed by starting from D‐galactose (9) and D‐fucose (10), respectively. The 5‐epimerization by a Mitsunobu inversion of the open‐chain D‐hexoses was the key step for these routes. Furthermore, the conversion of 2 into peracetylated TDP‐6‐deoxy‐α‐L‐altrose (3a) was achieved by the cycloSal approach. However, the final deacetylation led to an unexpected side‐reaction resulting in the previously unknown 6‐deoxy‐α‐L‐altropyranose 1,3‐cyclophosphate (4).
[n]Pseudorotaxanes (n = 2, 3) from Self‐Assembly of Two Cryptands and a 1,2‐Bis(4‐pyridinium)ethane Derivative
Authors: Yan Xuzhou , Chi Xiaodong , Wei Peifa , Zhang Mingming , Huang Feihe
Published: September 2012

Efficient host–guest complexation and interesting self‐assembled structures formed between two crown ether‐based cryptands and a 1,2‐bis(4‐pyridinium)ethane derivative 3 are reported. By self‐assembly of cis‐dibenzo‐24‐crown‐8‐based cryptand 1 and guest 3, a [3]pseudorotaxane was formed in solution, which further formed a supramolecular poly[3]pseudorotaxane structure in the solid state driven by π‐π stacking interactions. Meanwhile, a [2]pseudorotaxane, obtained from self‐assembly of a bis(m‐phenylene)‐32‐crown‐10‐based cryptand 2 and guest 3, can form a supramolecular poly[2]pseudorotaxane structure in the solid state. This difference in the binding model reflects the diversity of host–guest chemistry of crown ether‐based cryptands. Furthermore, these host–guest recognition processes and self‐assembled structures were fully characterized by 1H NMR, UV/Vis spectroscopy, electrospray ionization mass spectrometry, and single‐crystal X‐ray analysis. Interestingly, formation of the [3]pseudorotaxane between cryptand 1 and guest 3 can be reversibly controlled by adding and removing potassium cations in acetone. This reversible complexation process provides a simple on/off mechanism that can be used in the construction of controllable molecular switches.
Derivatives of (–)‐Isosteviol with Expanded Ring D and Various Oxygen Functionalities
Authors: Lohoelter Christina , Schollmeyer Dieter , Waldvogel Siegfried R.
Published: September 2012

(–)‐Isosteviol is a unique ex‐chiral‐pool building block that is readily available. Both functional groups are aligned in a concave manner. The methyl moiety on the backbone also points in this direction, creating a strong asymmetric environment close to these functional groups. The slightly divergent orientation of the keto and carboxy functions limits its use in the construction of supramolecular architectures as optically pure divalent building blocks. By selective transformations, ring D of (–)‐isosteviol can be expanded and equipped with oxygen‐containing functionalities, providing a variety of useful and rigid building blocks with defined stereochemistry.
Calibration and use of the polar organic chemical integrative sampler—a critical review
Authors: Harman Christopher , Allan Ian John , Vermeirssen Etiënne L. M.
Published: September 2012

The implementation of strict environmental quality standards for polar organic priority pollutants poses a challenge for monitoring programs. The polar organic chemical integrative sampler (POCIS) may help to address the challenge of measuring low and fluctuating trace concentrations of such organic contaminants, offering significant advantages over traditional sampling. In the present review, the authors evaluate POCIS calibration methods and factors affecting sampling rates together with reported environmental applications. Over 300 compounds have been shown to accumulate in POCIS, including pesticides, pharmaceuticals, hormones, and industrial chemicals. Polar organic chemical integrative sampler extracts have been used for both chemical and biological analyses. Several different calibration methods have been described, which makes it difficult to directly compare sampling rates. In addition, despite the fact that some attempts to correlate sampling rates with the properties of target compounds such as log KOW have been met with varying success, an overall model that can predict uptake is lacking. Furthermore, temperature, water flow rates, salinity, pH, and fouling have all been shown to affect uptake; however, there is currently no robust method available for adjusting for these differences. Overall, POCIS has been applied to a wide range of sampling environments and scenarios and has been proven to be a useful screening tool. However, based on the existing literature, a more mechanistic approach is required to increase understanding and thus improve the quantitative nature of the measurements. Environ. Toxicol. Chem. 2012; 31: 2724–2738. © 2012 SETAC
Transoral resection of pharyngeal cancer: Summary of a National Cancer Institute Head and Neck Cancer Steering Committee Clinical Trials Planning Meeting, November 6–7, 2011, Arlington, Virginia
Authors: Adelstein David J. , Ridge John A. , Brizel David M. , Holsinger F. Christopher , Haughey Bruce H. , O'Sullivan Brian , Genden Eric M. , Beitler Jonathan J. , Weinstein Gregory S. , Quon Harry , Chepeha Douglas B. , Ferris Robert L. , Weber Randal S. , Movsas Benjamin , Waldron John , Lowe Val , Ramsey Scott , Manola Judith , Yueh Bevan , Carey Thomas E. , Bekelman Justin E. , Konski Andre A. , Moore Eric , Forastiere Arlene , Schuller David E. , Lynn Jean , Ullmann Claudio Dansky
Published: September 2012

Recent advances now permit resection of many pharyngeal tumors through the open mouth, an approach that can greatly reduce the morbidity of surgical exposure. These transoral techniques are being rapidly adopted by the surgical community and hold considerable promise. On November 6–7, 2011, the National Cancer Institute sponsored a Clinical Trials Planning Meeting to address how to further investigate the use of transoral surgery, both in the good prognosis human papillomavirus (HPV)–initiated oropharyngeal cancers, and in those with HPV‐unrelated disease. The proceedings of this meeting are summarized. © 2012 Wiley Periodicals, Inc. Head Neck, 2012
Perceived supervisor support climate, perceived investment in employee development climate, and business‐unit performance
Authors: Dysvik Anders , Kuvaas Bård
Published: September 2012

Perceived supervisor support (PSS) has been found to predict employee in‐role and extra‐role performance at the individual level of analysis. With respect to the unit level of analysis, the research on the predictive role of PSS remains limited. In particular, calls have been made for research on the role of leadership in facilitating perceived HR practices at the business‐unit level and on the role of line managers as implementers of such systems. In response to such calls, this study investigated the associations between PSS climate, perceived investment in employee development (PIED) climate, and business‐unit performance among 75 gas stations located in Norway. The results showed that the PSS climate was positively related to both the PIED climate and the business‐unit performance. This study contributes to research on PSS by extending the prior findings at the individual level to the unit level of analysis. Also, the study contributes to the research on perceived HR practices by demonstrating the facilitative role of the PSS climate. Finally, the study contributes to the research on shared perceptions of HR practices generally and the concept of the “strength” of the HRM system in particular. Implications for practice and future research are discussed. © 2012 Wiley Periodicals, Inc.
A reexamination of the web‐based job demand for PHR and SPHR certifications in the United States
Authors: Lyons Brian D. , Mueller Lorin M. , Gruys Melissa L. , Meyers Aaron J.
Published: September 2012

Over the past decade, the exponential growth in Professional in Human Resources (PHR) and Senior Professional in Human Resources (SPHR) certifications awarded by the Human Resource Certification Institute substantiates the need to reexamine the base rate of HR job announcements that require or prefer such certification. Based on a sample of Web‐based job announcements in 2002, Aguinis, Michaelis, and Jones (2005) reported that only 1.4 percent required or preferred PHR/SPHR certification. Using a similar design, the current study found that 15.6 percent of job announcements required or preferred PHR/SPHR certification, which is nearly 11 times the rate found in the Aguinis et al. (2005) study. Results also suggested the demand for PHR/SPHR certification was positively related to experience, educational level, and job title level, with the base rate reaching 25.1 percent for managerial HR roles.
Molecular patterns in the evolution of serrated lesion of the colorectum
Authors: Gaiser Timo , Meinhardt Sandra , Hirsch Daniela , Killian Jonathan Keith , Gaedcke Jochen , Jo Peter , Ponsa Immaculada , Miró Rosa , Rüschoff Josef , Seitz Gerhard , Hu Yue , Camps Jordi , Ried Thomas
Published: September 2012

Colorectal cancer (CRC) mostly develops from a variety of polyps following mainly three different molecular pathways: chromosomal instability (CIN), microsatellite instability (MSI) and CpG island methylation (CIMP). Polyps are classified histologically as conventional adenomas, hyperplastic polyps, sessile serrated adenomas/polyps (SSA/P) and traditional serrated adenomas (TSA). However, the association of these polyps with the different types of CRCs and the underlying genetic and epigenetic aberrations has yet to be resolved. In order to address this question we analyzed 140 tumors and 20 matched mucosae by array comparative genomic hybridization, by sequence analysis of the oncogenes BRAF, KRAS,
PI3K3CA and by methylation arrays. MSI was tested indirectly by immunohistochemistry (IHC) and a loss of MLH1, MSH2, MSH6 or PMS2 was assigned as high microsatellite instability (MSI‐H), while low microsatellite instability (MSI‐L) was defined as MGMT IHC negativity only. CIN was detected in 78% of all MSI‐H CRCs, most commonly as a gain of chromosome 8. Methylation data analyses allowed classification of samples into four groups and detected similar methylation profiles in SSA/P and MSI‐H CRC. TSA also revealed aberrant methylation pattern, but clustered more heterogeneously and closer to microsatellite stable (MSS) CRCs. SSA/P, TSA and MSI‐H CRCs had the highest degree of promotor methylation (CIMP pathway). Chromosomal instability, in contrast to the established doctrine, is a common phenomenon in MSI CRCs, yet to a lower extent and at later stages than in MSS CRCs. Methylation analyses suggest that SSA/P are precursors for MSI‐H CRCs and follow the CIMP pathway.
Functional effect of polymorphisms in 15q25 locus on CHRNA5 mRNA, bulky DNA adducts and TP53 mutations
Authors: Tekpli Xavier , Landvik Nina E. , Skaug Vidar , Gulsvik Amund , Haugen Aage , Zienolddiny Shanbeh
Published: September 2012

Genome‐wide association studies have demonstrated that genetic polymorphisms influence the risk of developing lung cancer. Nicotinic acetylcholine receptor alpha3, alpha5 and beta4 genes (CHRNA3, CHRNA5 and CHRNB4) cluster at the 15q25.1 lung cancer susceptibility locus. We genotyped 310 patients with non‐small cell lung cancer and a control group of 348 cancer‐free individuals for seven sequence variants located in CHRNA3 and CHRNA5 genes. Two of the polymorphisms (rs3829787 and rs3841324) statistically influenced the risk of developing lung cancer. We found that four of the variants (rs3829787, rs3841324, rs588765 and rs3743073) were associated with differential levels of genetic alterations measured as the levels of hydrophobic DNA adducts in the adjacent histologically normal tissue of the lung cancer patients and as TP53 mutations in their lung tumors. The seven sequence variants formed three haplotypes with a frequency above 5%. The two most frequent haplotypes were associated with the risk of developing lung cancer and with smoking‐related DNA alterations. We also found an association between CHRNA5 mRNA levels and the sequence variants or haplotypes. In conclusion, our results showed that several of the polymorphisms and their haplotypes in CHRNA5/CHRNA3 genes may have functional effects on (i) CHRNA5 mRNA levels, (ii) polycyclic aromatic hydrocarbon–DNA adduct levels, (iii) TP53 mutations and (iv) susceptibility to lung cancer.
Liquid Crystals at Interfaces
Authors: Gupta Raj Kumar , Manjuladevi V.
Published: September 2012

The ordering in liquid crystals (LCs) can be influenced by an interface. Some of these molecules adsorbed at the air‐water interface yield a stable Langmuir monolayer. They exhibit numerous surface phases, which are classified on the basis of intermolecular separation and ordering. These surface phases are governed by the molecular interactions and the ambient experimental conditions such as temperature, humidity, pH, and ion content of the subphase. In this article, the role of molecular interactions on the surface behavior of several rodlike LCs are discussed. The Langmuir monolayer of a cholesteric LC exhibits an interesting low density liquid (L1′) phase with tilted molecules. Brewster angle microscopy reveals stripe patterns, which arise due to the precession of the tilted molecules. It is demonstrated that this molecular precession can be controlled by the relative humidity, presence of cations in the subphase, and incorporation of appropriate molecular species. The Langmuir monolayer and Langmuir‐Blodgett films of a novel rod‐disc hybrid LC are discussed.
miRNAs in cardiac disease: Sitting duck or moving target?
Authors: Hynes Carly J. , Clancy Jennifer L. , Preiss Thomas
Published: September 2012

Emerging findings indicate that cells can produce both micro (mi)RNAs and their messenger (m)RNA targets in multiple processing variants in a tissue‐ and developmental stage‐selective manner. Specifically, we find that cells accumulate a greater range of functional miRNAs than hitherto expected, whereas mRNAs with alternative 3′ untranslated regions that include varying numbers of miRNA target sites are also seen to be common. This has important implications for both our understanding of miRNA function in a given biological context and the design of successful strategies for experimental or therapeutic intervention. In this review, we relate these new phenomena to miRNAs in the heart, where they are known to play critical roles during normal function as well as in cardiac disease. © 2012 IUBMB IUBMB Life, 64(11): 872–878, 2012
Synthesis and application of nanostructured calcium phosphate ceramics for bone regeneration
Authors: Alves Cardoso D. , Jansen J. A. , G. Leeuwenburgh S. C.
Published: September 2012

In the past two decades, nanotechnology has entered the field of regenerative medicine, resulting in the development of a novel generation of instructive, nanostructured biomaterials that are able to orchestrate cellular behavior by presenting specific morphological and biological cues. Using nanotechnology, materials containing nanosized features (e.g., pores, patterns, textures, grain sizes) can be obtained that exhibit properties that are considerably altered compared with micron‐structured materials. Inspired by the hierarchical nanostructure of bone, the application of nanostructured materials for bone regeneration is gaining increasing interest in the field of biomaterials research. Because crystallographic and chemical studies have shown that synthetic hydroxyapatite closely resembles the inorganic phase found in bone and teeth, synthesis and applications of nanostructured calcium phosphate ceramics have been reviewed. Synthesis techniques for the preparation of calcium phosphate nanoparticles include precipitation, sol–gel, and hydrothermal processes, whereas four main biomedical applications of nanostructured calcium phosphate ceramics in bone regeneration have been addressed in more detail, that is, (1) polymer/calcium phosphate nanocomposites, (2) nanostructured monophasic calcium phosphate bone fillers, (3) nanostructured precursor phases for calcium phosphate cements, and (4) nanostructured calcium phosphate coatings. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Hepatocellular carcinoma in a North American population: Does hepatobiliary MR imaging with Gd‐EOB‐DTPA improve sensitivity and confidence for diagnosis?
Authors: Bashir Mustafa R. , Gupta Rajan T. , Davenport Matthew S. , Allen Brian C. , Jaffe Tracy A. , Ho Lisa M. , Boll Daniel T. , Merkle Elmar M.
Published: September 2012

Purpose:

To evaluate the value of hepatobiliary phase imaging for detection and characterization of hepatocellular carcinoma (HCC) in liver MRI with Gd‐EOB‐DTPA, in a North American population.

Materials and Methods:

One hundred MRI examinations performed with the intravenous injection of Gd‐EOB‐DTPA in patients with cirrhosis were reviewed retrospectively. Nodules were classified as HCC (n = 70), indeterminate (n = 33), or benign (n = 22). Five readers independently reviewed each examination with and without hepatobiliary phase images (HBP). Lesion conspicuity scores were compared between the two readings. Lesion detection, confidence scores, and receiver operating characteristic (ROC) analysis were compared.

Results:

Lesion detection was slightly improved for all lesion types with the inclusion of the HBP, and was substantially higher for small HCCs (96.0% versus 85.3%). Mean confidence scores for the diagnosis of HCC increased for HCCs overall and each size category (P < 0.001). Diagnostic performance improved with the addition of the HBP (aggregate AROC 87.7% versus 80.0%, P < 0.01), and sensitivity for characterization improved (90.9% versus 78.3%, P < 0.01) while specificity was unchanged.

Conclusion:

Hepatobiliary phase imaging may improve small lesion detection (<1 cm) and characterization of lesions in general, in MRI of the cirrhotic liver with Gd‐EOB‐DTPA. J. Magn. Reson. Imaging 2013;37:398–406. © 2012 Wiley Periodicals, Inc.
Reproducibility of rapid short echo time CSI at 3 tesla for clinical applications
Authors: Van Cauter Sofie , Sima Diana M. , Luts Jan , ter Beek Leon , Ribbens Annemie , Peeters Ronald R. , Osorio Garcia Maria I. , Li Yuquan , Sunaert Stefan , Van Gool Stefaan W. , Van Huffel Sabine , Himmelreich Uwe
Published: September 2012

Purpose:

To validate the reproducibility of a chemical shift imaging (CSI) acquisition protocol with parallel imaging, using automated repositioning software.

Materials and Methods:

Ten volunteers were imaged three times on two different 3 Tesla (T) MRI scanners, receiving anatomical imaging and two identical CSI measurements, using automated repositioning software for consistent repositioning of the CSI grid. Offcenter parameters of the CSI plane were analyzed. Coefficients of variation (CoV), Cramér‐Rao lower bounds (CRLB), intraclass correlation coefficients (ICC), and coefficients of repeatability (CoR) for immediate repetition and between scanners were calculated for N‐acetylaspartate, total choline, creatine, myo‐inositol (Myo) and glutamine+glutamate (Glx). Proportions of variance reflecting the effect of voxel location, volunteer, repetition, time instance and scanner were calculated from an analysis of variance analysis.

Results:

The offcenter vector and angulations of the CSI grid differed less than 1 mm and 2° between all measurements. The mean CoV and CRLB were less than 30% for all metabolites, except for Myo. The variance due to voxel location in the volume of interest and the error represent the largest contributions in variability. The ICC is the lowest for Myo and Glx. CoR for immediate repetition and between scanners display values between 22 and 83%.

Conclusion:

We propose a CSI protocol with acceptable reproducibility, applicable in clinical routine. J. Magn. Reson. Imaging 2013;37:445–456. © 2012 Wiley Periodicals, Inc.
Emotion regulation as a boundary condition of the relationship between team conflict and performance: A multi‐level examination
Authors: Jiang Jane Yan , Zhang Xiao , Tjosvold Dean
Published: September 2012

Although task conflict is widely believed to be beneficial whereas relationship conflict is destructive, evidence overall does not support this conclusion. This study develops the idea that the emotion regulation abilities of team members affect how they manage task and relationship conflict, both as individuals and as a team. Findings from a field study involving 39 teams support the argument that individuals skilled in emotion regulation can take advantage of task conflict to perform effectively and limit the negative impact of relationship conflict. Groups that have individuals highly skilled in emotion regulation were also found to make good use of team conflict. Results suggest that emotion regulation skills contribute to the effective management of task conflict and relationship conflict at both individual and group levels. Copyright © 2012 John Wiley & Sons, Ltd.
Bioactivity of probiotic whey cheese: characterization of the content of peptides and organic acids
Authors: Madureira Ana R , Soares José C , Amorim Maria , Tavares Tânia , Gomes Ana M , Pintado Maria M , Malcata Francisco X
Published: September 2012

Background

Probiotic whey cheeses have been produced for several years. It is recognized that several bacterium‐mediated metabolic activities contribute differently to the final sensory and nutritional profiles of dairy products. Hence the metabolic activity of probiotic strains in a whey cheese and their contribution to the bioactivity of such matrices were investigated here, including in particularBifidobacterium animalis,Lactobacillus acidophilusandLactobacillus casei.

Results

BothL. caseiandB. animalisproduce lactic and acetic acids, whereasL. acidophilusproduce mainly lactic acid; these metabolites may be considered bioprotection factors. Water‐soluble extracts (WSE) obtained from these cheese matrices were subjected to ultrafiltration through a 3kDacut‐off membrane, and the eluted peptides were resolved by high‐performance liquid chromatography. Different qualitative and quantitative profiles were obtained, depending on the strain.WSEwere further assayed for their ability to inhibit angiotensin‐converting enzyme; the <3kDafraction exhibited higher activities in the case ofL. caseiandB. animalisthan the control andL. acidophilus.

Conclusion

Whey cheeses with higher nutritional value were those inoculated withL. casei.
The effect of fish matrix on the enzyme‐linked immunosorbent assay of antibiotics
Authors: Wang Xiudan , Lin Hong , Sui Jianxin , Cao Limin
Published: September 2012

BACKGROUND

The matrix effect is considered to be a problem in the immunoassay of foodstuffs. However, information on the interference from aquatic products, as well as the mechanism involved, is very limited. In this study, using three flatfishes (Scophthalmus maximus, Paralichthys olivaceus and Cymoglossus robustus) as samples, the effect of the fish matrix on the competitive indirect enzyme‐linked immunosorbent assay (ci‐ELISA) of antibiotic (norfloxacin) residues was investigated. The mechanism of the observed matrix effect is also preliminarily discussed.

RESULTS

Within the working range of the calibration curves, a significant (P = 0.05) but irregular variation in the inhibition ratio was observed in the presence of fish extracts. Further experiments revealed that such a matrix effect could be caused by some water‐soluble fish proteins with a wide range of molecular weight (from below 14.4 kDa to about 116.0 kDa), and the ions from fish muscles may also contribute to the interference. The results of western blotting indicated that some fish protein components might effectively bind with antibody reagents used.

CONCLUSION

Significant interference in the immunoassay of norfloxacin was observed in the presence of fish matrix. Some proteins and ions were demonstrated to contribute to the matrix effect investigated. Although the detailed mechanism is still unclear, the non‐specific interaction between fish proteins and immunoglobulin G (IgG) or horseradish peroxidase (HRP) labelled IgG was assumed to be an important source of the matrix effect in immunoassays. © 2012 Society of Chemical Industry
The use of sensory attributes, sugar content, instrumental data and consumer acceptability in selection of sweet potato varieties
Authors: Laurie Sunette M , Faber Mieke , Calitz Frikkie J , Moelich Erika I , Muller Nina , Labuschagne Maryke T
Published: September 2012

Background

As eating quality is important for adoption of new varieties, nine orange‐fleshed and three cream‐fleshed sweet potato varieties were assessed for sensory characteristics, dry mass and free sugar content, instrumental texture and colour and consumer acceptability (n =  216) in a peri‐urban South African setting.

Results

Cream‐fleshed varieties were higher in yellow‐green colour and sweet potato‐like flavour and lower in graininess. Orange‐fleshed varieties were higher in pumpkin‐like flavour, orange colour, discolouration and sucrose content. Partial least squares regression analysis showed that the most accepted varieties (Impilo, Excel, Resisto, 2001_5_2, Serolane, W‐119 and Monate) were associated with sweet flavour, dry mass and maltose content, while the least accepted varieties (Beauregard, Khano and 1999_1_7) were associated with wateriness. Pearson correlation analysis highlighted correlations of sensory attributes yellow and orange with instrumental colour measurements (colour a* and colour b*), instrumental firmness with sensory firmness, dry mass with sensory wateriness, and maltose content with sensory sweet and sweet potato‐like flavour. The varieties were clustered into three groups. Consumer acceptability for eating quality correlated with maltose content, dry mass and sweet flavour.

Conclusion

Chemical and instrumental measurements were identified to evaluate key attributes and will be useful in the intermediate phases of sweet potato varietal development.
Next generation organelles: Structure and role of germ granules in the germline
Authors: Gao Ming , Arkov Alexey L.
Published: September 2012

Germ cells belong to a unique class of stem cells that gives rise to eggs and sperm, and ultimately to an entire organism after gamete fusion. In many organisms, germ cells contain electron‐dense structures that are also known as nuage or germ granules. Although germ granules were discovered more than 100 years ago, their composition, structure, assembly, and function are not fully understood. Germ granules contain non‐coding RNAs, mRNAs, and proteins required for germline development. Here we review recent studies that highlight the importance of several protein families in germ granule assembly and function, including germ granule inducers, which initiate the granule formation, and downstream components, such as RNA helicases and Tudor domain–Piwi protein–piRNA complexes. Assembly of these components into one granule is likely to result in a highly efficient molecular machine that ensures translational control and protects germline DNA from mutations caused by mobile genetic elements. Furthermore, recent studies have shown that different somatic cells, including stem cells and neurons, produce germ granule components that play a crucial role in stem cell maintenance and memory formation, indicating a much more diverse functional repertoire for these organelles than previously thought. Mol. Reprod. Dev. 80:610–623, 2013. © 2012 Wiley Periodicals, Inc.
Cell volume regulation in mammalian oocytes and preimplantation embryos
Authors: Baltz Jay M. , Zhou Chenxi
Published: September 2012

The earliest stages of preimplantation embryos are particularly sensitive to increased osmolarity, even within the physiological range. This sensitivity contributed to persistent developmental arrest, even when embryos were cultured in vitro in older, conditioned culture media, and seems to arise when embryos at the 1‐ and 2‐cell stages accumulate inorganic ions used for cell volume homeostasis at too high a level, through activation of coupled Na+/H+ and HCO/Cl− exchange. Such accumulation of inorganic ions can be disruptive since, above a certain level, the increased ionic strength disrupts cellular biochemistry and macromolecular functions and alters membrane potential. To counter this, embryos have evolved mechanisms of cell volume regulation that are unique to early preimplantation embryogenesis. The primary role of these is glycine accumulation via the GLYT1 transporter, with a secondary contribution by betaine accumulation via the SIT1 transporter. Independent cell‐volume regulation first arises in the oocyte only after ovulation is triggered, when the strong oocyte‐zona pellucida adhesion present in germinal vesicle stage oocytes in the ovarian follicle is released and GLYT1 becomes activated to begin accumulating glycine. Open questions still remain regarding how these processes are regulated. Mol. Reprod. Dev. 79: 821–831, 2012. © 2012 Wiley Periodicals, Inc.
Menstrual management and intellectual disability: New perspectives
Authors: Griffin Jeni , Carlson Glenys , Taylor Miriam , Wilson Jill
Published: September 2012

Assessment and education in self‐care, ‘activities of daily living’ (ADL) have provided a traditional focus among occupational therapists. Available literature supports the teaching of self‐care skills to clients who have severe and profound intellectual disability. Although some programmes have been developed to deal with menstrual management for women with mild and moderate intellectual disability, studies addressing the needs of women with more severe disabilities (high support needs) are sparse, and generally involve only small numbers of women. A menstrual management project based at the University of Queensland developed a model of intervention to assist with menstrual management for women with high support needs. Case studies illustrate three key areas of intervention: (1) assessment of the women's actual or potential menstrual management skills; (2) increasing awareness of attitudes towards menstruation for women who have intellectual disability, among people assisting them; and (3) provision of a range of information, processes and resources to assist educators, families and others providing personal assistance, with informed menstrual management for these women. Positive gains made by four women with high support needs are presented. Relevant issues and difficulties are discussed.
Occupational therapy and school‐to‐work transition: A preventive education model
Authors: McInerney Claudia A. , McInerney Maurice
Published: September 2012

This report describes a preventive education model of occupational therapy that anticipates and prevents problems of postsecondary school transition among students with disabilities. Under the model, therapists assess students' functional skills in three transition related areas: personal attitudes, interpersonal behaviors and work habits. Therapists then preventively train these skills through an individualized program of direct therapy with consultation or indirect therapy with on‐going monitoring of student performance. These therapeutic activities are integrated within existing curricular activities at each grade level and coordinated across grades throughout the student's public school career. Research evidence and case history illustrations about the effectiveness of the model are presented. The report recommends strategies to ensure that students with disabilities acquire prerequisite skills before — not after — beginning their transition from high school to work and independent living in the community.
Sensorimotor coordination in boys with fragile X syndrome
Authors: Friefeld Sharon J. , Macgregor Daune
Published: September 2012

The sensorimotor coordination of 14 boys diagnosed with fragile X syndrome was assessed by standardised motor tests, including the McCarron Assessment of Neuromuscular Development (MAND) and the Beery Test of Visual‐Motor Integration — Revised. Clinical observations of quality of movement during gross and fine motor activities were made and the sessions videotaped to objectify test results. Subjects ranged in age from 3;11 years to 14;2 years (mean = 8;2 years). According to the MAND assessment, 80% of the children's motor functioning was severely impaired. The children had the most difficulty on motor tasks requiring visual‐motor integration and balance. Their fine motor skills were superior to their gross motor skills (F = 4.57; p < 0.05), and the older boys (>11 years) performed significantly better on tasks of bimanual dexterity. The presence of mild hypotonicity and finger joint hyperextensibility was noted in most subjects (100% among the younger children, 57–86% among those over 11 years). This study is viewed as a preliminary examination of the clinical characteristics of motor proficiency in children diagnosed with fragile X syndrome. Although its results are inconclusive because of the small sample size, the severity of motor skills was consistent throughout the sample, and the superiority of the children's fine motor performance is worthy of note.
An investigation into the effects of structured music workshops with adults with mental handicap
Authors: Macdonald Raymond A. R. , O'Donnell Patrick J.
Published: September 2012

This study investigated the effects of structured group workshops for a population with special needs. Twenty subjects, each with a mild or moderate mental handicap, attended a series of 10 weekly 1‐hour music workshops on the structured group playing of a Javanese Gamelan. Twenty subjects formed a non‐intervention control group. The experimental hypothesis was that participation in the experimental group would produce significant improvements in musical ability as measured by the Rossi test of musical ability, devised and validated for use in this study. Significant gains in communication skills as measured by the Communication Assessment Profile for Adults with a Mental Handicap (CASP) and self‐esteem levels measured by the Khalid semantic differential technique were also postulated. It was also suggested that these gains would be significantly correlated. Results show significant gains in musical ability (instrumental rhythm production: t = 5.67, d.f. = 29, p < 0.01 and simple rhythm production: t = 8.42, d.f. = 29, p < 0.01) and communication skills (t = 4.69, d.f. = 29, p < 0.01). Moreover these results are significantly correlated (r = 0.59, p < 0.05, r = 0.75, p < 0.05, r = 0.56, p < 0.05). A ceiling effect was obtained in the measurement of self‐esteem. It is suggested that these gains derive from certain aspects of the musical communicative environment at the workshops. Suggestions for future research involve examining the possible influences on these developments.
Enhanced thermal conductivity and dimensional stability of flexible polyimide nanocomposite film by addition of functionalized graphene oxide
Authors: Tseng I‐Hsiang , Chang Jen‐Chi , Huang Shih‐Liang , Tsai Mei‐Hui
Published: September 2012

Polyimide (PI) nanocomposites with both enhanced thermal conductivity and dimensional stability were achieved by incorporating glycidyl methacrylate‐grafted graphene oxide (g‐GO) in the PI matrix. The PI/g‐GO nanocomposites exhibited linear enhancement in thermal conductivity when the amount of incorporated g‐GO was less than 10 wt%. With the addition of 10 wt% of g‐GO to PI (PI/g‐GO‐10), the thermal conductivity increased to 0.81 W m−1 K−1 compared to 0.13 W m−1 K−1 for pure PI. Moreover, the PI/g‐GO‐10 composite exhibited a low coefficient of thermal expansion (CTE) of 29 ppm °C−1. The values of CTE and thermal conductivity continuously decreased and increased, respectively, as the g‐GO content increased to 20 wt%. Combined with excellent thermal stability and high mechanical strength, the highly thermally conducting PI/g‐GO‐10 nanocomposite is a potential substrate material for modern flexible printed circuits requiring efficient heat transfer capability.
Electrochemical synthesis of a double‐layer film of ZnO nanosheets/nanoparticles and its application for dye‐sensitized solar cells
Authors: Kung Chung‐Wei , Chen Hsin‐Wei , Lin Chia‐Yu , Lai Yi‐Hsuan , Vittal R. , Ho Kuo‐Chuan
Published: September 2012

A double‐layer film, consisting of an upper layer of ZnO nanosheets and a lower layer of ZnO nanoparticles (designated as ZnONS/NP), was synthesized for the photoanode of a dye‐sensitized solar cell (DSSC) by a one‐step potentiostatic electrodeposition on a conducting fluorine‐doped tin oxide substrate at 70 °C in a solution containing zinc nitrate and sodium acetate, followed by the pyrolysis of the film at 300 °C. The growth mechanism of the double‐layer nanostructure was studied by monitoring the morphological changes at various periods of electrodeposition. The effects of the concentration of acetate anion on the morphology of the double‐layer structure were also studied. The double‐layer film of ZnONS/NP showed a better self‐established light scattering property, compared with that of a thin film of ZnO nanoparticles, prepared without acetate anion. The concentration of an acetate anion in the electrolyte for the electrodeposition of the double‐layer film, the electrodeposition period, and the period for dye adsorption were optimized for obtaining the best performance for a DSSC with a photoanode consisting of the double layer. A metal‐free dye, coded as D149, was used in this research. A conversion efficiency of 4.65% was achieved for a DSSC (0.2376 cm2) with the photoanode, consisting of the double‐layer film, under 100 mW/cm2 illumination in the wavelength range of 400–800 nm. X‐ray diffraction patterns, thermo gravimetric curves, elemental analysis, scanning electron microscopic images, transmission electron microscopic image, transmission spectra, and electrochemical impedance spectra were used to explain observations. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis of self‐assembled sphingolipid conjugates and their morphology effect on anticancer therapeutic potency
Authors: Jung Bokyung , Jeong Yong‐Cheol , Kim Jong‐Duk
Published: September 2012

The shape of self‐assembling polymer–drug conjugates, influencing the cellular uptake, is one of the important factors to be considered for effective drug delivery. In this study, we described synthesis of polymeric drug conjugates of different morphologies with phytosphingosine (PHS) as a hydrophobic model drug and poly(amino acid) as a hydrophilic host polymer. By varying the amount of PHS grafted to poly(amino acid), PHS–poly(amino acid) conjugates exhibited morphological transition from spherical to worm‐like micellar aggregates in the aqueous media. We investigated the physicochemical properties of self‐assembled structures in terms of hydrodynamic size, surface charge, and critical aggregation concentration. The anticancer therapeutic potency of these self‐assembled structures was also discussed in terms of cellular uptake and cytotoxicity of prodrug micelles as a function of dose and time by in vitro cell study. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Ethylene glycol‐based ionic liquids via azide/alkyne click chemistry
Authors: Zare Parvin , Mahrova Maria , Tojo Emilia , Stojanovic Anja , Binder Wolfgang H.
Published: September 2012

A facile synthetic route for the preparation of dicationic ethylene glycol based‐ionic liquids (ILs) via the azide/alkyne “click” reaction is presented. The copper(I) catalyzed, microwave‐assisted azide/alkyne “click” reaction between diazido‐ethylene glycols and the corresponding alkyne containing IL‐head group enables a simple preparation of different sets of poly(ethylene glycol)‐based ILs. Beside tetra‐ and hexa(ethylene glycol)‐based ILs, also oligomeric (Mn = 400 g/mol) and polymeric ILs (Mn up to 1550 g/mol) could be prepared in good yield and with full conversion of the ionic head group. The prepared ILs were extensively characterized via NMR spectroscopy and ESI‐time‐of‐flight (TOF) mass spectroscopy, revealing the formation of multiply charged ions in the negative mode. Thermal stability proved to be exceptionally high (up to 300 °C) together with low glass‐transition temperatures. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Reassessing the folding of the KIX domain: Evidence for a two‐state mechanism
Authors: Morrone Angela , Giri Rajanish , Brunori Maurizio , Gianni Stefano
Published: September 2012

The debate about the presence and role of intermediates in the folding of proteins has been a critical issue, especially for fast folders. One of the classical methodologies to identify such metastable species is the “burst‐phase analysis,” whereby the observed signal amplitude from stopped‐flow traces is determined as a function of denaturant concentration. However, a complication may arise when folding is sufficiently fast to jeopardize the reliability of the stopped‐flow technique. In this study, we reassessed the folding of the KIX domain from cAMP Response Element‐Binding (CREB)‐binding protein, which has been proposed to involve the formation of an intermediate that accumulates in the dead time of the stopped flow. By using an in‐house‐built capillary continuous flow with a 50‐μs dead time, we demonstrate that this intermediate is not present; the problem arose because of the instrumental limitation of the standard stopped flow to assess very fast refolding rate constants (e.g., ≥500 s−1).
NMR structure of the calflagin Tb24 flagellar calcium binding protein of Trypanosoma brucei
Authors: Xu Xianzhong , Olson Cheryl L. , Engman David M. , Ames James B.
Published: September 2012

Flagellar calcium binding proteins are expressed in a variety of trypanosomes and are potential drug targets for Chagas disease and African sleeping sickness. The flagellar calcium binding protein calflagin of Trypanosoma brucei (called Tb24) is a myristoylated and palmitoylated EF‐hand protein that is targeted to the inner leaflet of the flagellar membrane. The Tb24 protein may also interact with proteins on the membrane surface that may be different from those bound to flagellar calcium binding proteins (FCaBPs) in T. cruzi. We report here the NMR structure of Tb24 that contains four EF‐hand motifs bundled in a compact arrangement, similar to the overall fold of T. cruzi FCaBP (RMSD = 1.0 Å). A cluster of basic residues (K22, K25, K31, R36, and R38) located on a surface near the N‐terminal myristoyl group may be important for membrane binding. Non‐conserved residues on the surface of a hydrophobic groove formed by EF2 (P91, Q95, D103, and V108) and EF4 (C194, T198, K199, Q202, and V203) may serve as a target protein binding site and could have implications for membrane target recognition.
A bivariate Bayesian dose‐finding procedure applied to a seamless phase I/II trial in rheumatoid arthritis
Authors: Thygesen Helene , Dragalin Vladimir , Whitehead Anne , Whitehead John
Published: September 2012

We describe a dose escalation procedure for a combined phase I/II clinical trial. The procedure is based on a Bayesian model for the joint distribution of the occurrence of a dose limiting event and of some indicator of efficacy (both considered binary variables), making no assumptions other than monotonicity. Thus, the chances of each outcome are assumed to be non‐decreasing in dose level. We applied the procedure to the design of a placebo‐controlled, sequential trial in rheumatoid arthritis, in each stage of which patients were randomized between placebo and all dose levels that currently appeared safe and non‐futile. On the basis of data from a pilot study, we constructed five different scenarios for the dose–response relationships under which we simulated the trial and assessed the performance of the procedure. The new design appears to have satisfactory operating characteristics and can be adapted to the requirements of a range of trial situations. Copyright © 2012 John Wiley & Sons, Ltd.
Supporting Smallholders to Access Sustainable Supply Chains: Lessons from the Indian Cotton Supply Chain
Authors: Fayet Laia , Vermeulen Walter J.V.
Published: September 2012

A significant number of different sustainable initiatives have emerged to improve sustainability and inclusion of small farmers in global supply chains. These include production process adjustment advice and implementation of different sustainable product standards. In practice two different approaches are taken. Development projects focus on enabling farmers to adjust their practices to Organic, Fairtrade and other standards requirements. In international trade, buyers from developed countries implement separate supply chain assurance systems. This article presents nine case studies of practices from both approaches in the cotton supply chain in India.

The results show improvements in the livelihoods of small farmers but increased market access depends on what approaches are used. The future challenge is to combine the different approaches, creating market links and enhancing supply chain efficiency while providing development support at community levels. With such a balance it will be possible to assure project sustainability and maximize long‐term economical, environmental and social benefits. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment
Electron propagator theory: an approach to prediction and interpretation in quantum chemistry
Authors: Ortiz Joseph Vincent
Published: September 2012

Electron propagator theory provides a practical means of calculating electron binding energies, Dyson orbitals, and ground‐state properties from first principles. This approach to ab initio electronic structure theory also facilitates the interpretation of its quantitative predictions in terms of concepts that closely resemble those of one‐electron theories. An explanation of the physical meaning of the electron propagator's poles and residues is followed by a discussion of its couplings to more complicated propagators. These relationships are exploited in superoperator theory and lead to a compact form of the electron propagator that is derived by matrix partitioning. Expressions for reference‐state properties, relationships to the extended Koopmans's theorem technique for evaluating electron binding energies, and connections between Dyson orbitals and transition probabilities follow from this discussion. The inverse form of the Dyson equation for the electron propagator leads to a strategy for obtaining electron binding energies and Dyson orbitals that generalizes the Hartree–Fock equations through the introduction of the self‐energy operator. All relaxation and correlation effects reside in this operator, which has an energy‐dependent, nonlocal form that is systematically improvable. Perturbative arguments produce several, convenient (e.g. partial third order, outer valence Green's function, and second‐order, transition‐operator) approximations for the evaluation of valence ionization energies, electron affinities, and core ionization energies. Renormalized approaches based on Hartree–Fock or approximate Brueckner orbitals are employed when correlation effects become qualitatively important. Reference‐state total energies based on contour integrals in the complex plane and gradients of electron binding energies enable exploration of final‐state potential energy surfaces. © 2012 John Wiley & Sons, Ltd.

This article is categorized under:

Electronic Structure Theory > Ab Initio Electronic Structure Methods