bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Properties of Quaternary Phosphonium‐based Anion Exchange Membrane for Fuel Cells
Authors: Jiang Lihua , Lin Xiaocheng , Ran Jin , Li Chuanrun , Wu Liang , Xu Tongwen
Published: September 2012

Quaternary phosphonium‐based polyelectrolyte was synthesized from bromomethylated poly(2,6‐dimethyl‐1,4‐ phenylene oxide) (BPPO) by functionalization with tris(2,4,6‐trimethoxyphenyl) phosphine (TTMPP). Typically, excellent solubility of the polyelectrolyte in polar solvents, such as NMP and DMSO, allowed a solution‐casting strategy for preparation of anion exchange membrane (AEM) with properly ordered hydrophilic/hydrophobic nano‐scale phase separation morphology, which was visible in atomic force microscopic phase images. Accordingly, the optimized ionmeric AEM exhibited excellent hydroxide conductivity of 110 mS/cm at 70°C, but extremely restricted linear expansion ratio of below 7% at the same temperature. Additionally, such membrane could maintain flexibility and conductivity after an immersion treatment in 1 mol/L NaOH solution at 60°C for about 100 h, implying its potential in alkaline fuel cells.
Cu2+ Detection with Gold Nanoparticles by Patterning Colorimetric Strips on a Filter Membrane Assembled in a Microfluidic Chip
Authors: Liu Yingyi , Yu Jie , Chen Wenwen , Liu Dingbin , Wang Zhuo , Jiang Xingyu
Published: September 2012

We have developed a microfluidic chip for colorimetric Cu2+ detection. In this chip, it is facile to do colorimetric Cu2+ detection based on gold nanoparticles. This method has a dynamic detection range from 0.75 to 50 µmol/L with only 20 µL solution including detection reagents and sample. The result can be readout by naked eye and photographed by digital cameras. With the help of image processing software, we could measure the RGB value and calculate the Blue/Red ratio for more accurate quantification. Tap water could be detected in this portable chip.
Odd‐Even Sequence Effect of Surface‐Mediated Peptide Assemblies Observed by Scanning Tunneling Microscopy
Authors: Guo Yuanyuan , Wang Chenxuan , Hou Jingfei , Yang Aihua , Zhang Xuemei , Wang Yibing , Zhang Min , Yang Yanlian , Wang Chen
Published: September 2012

The peptide assembly structures of polyglutamine (PolyQ) have been studied by using scanning tunneling microscopy (STM) with high spatial resolution in ambient conditions. 4,4′‐Bipyridyl (4Bpy) was introduced into the PolyQ7 and PolyQ8 peptide assemblies for labeling the C‐termini of the peptides. The fine structures of the 4Bpy‐PolyQ7 and 4Bpy‐PolyQ8 co‐assemblies are observed, and the statistics of the apparent peptide strand length reveal different length distributions for PolyQ7 and PolyQ8. One predominant apparent peptide strand length is observed for PolyQ7 reflecting one predominant peptide conformation in assembly structures, while three major apparent strand lengths can be identified with PolyQ8 reflecting three co‐existing peptide conformations in peptide assemblies. Such drastic difference in assembling characteristics can be considered as a reflection of asymmetric adsorption effect of peptides relating to odd‐even residue numbers of PolyQ7 and PolyQ8.
A Short and Flexible Synthetic Approach to the Naturally Occurring Racemic Neoclausenamide and Its Analogs
Authors: Dai Xijie , Huang Peiqiang
Published: September 2012

A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro‐selective vinylogous Mukaiyama type reaction (dr=12:1) and a highly diastereoselective tandem conjugate addition‐Davis oxidation of N‐Boc‐pyrrol‐2(5H)‐one 5 (dr=10:1). Remarkably, the skeleton of neoclausenamide, namely 8a, an analog of neoclausenamide, was built in just two steps with all the four stereogenic centers (relative stereochemistry) established correctly and in excellent diastereoselectivities.
Biomedical Effects and Nanosafety of Engineered Nanomaterials: Recent Progress
Authors: Wang Xiaofeng , Zhu Motao , Li Jingyuan
Published: September 2012

With the development of nanotechnology, there are growing concerns about biological effects and biosafety of engineered nanomaterials. On the other hand, nanoparticles are widely used in medical fields based on their novel interactions with biological entities. However, there are still a lot of challenges to establish systematic knowledge about nanotoxicology and develop biologically safer biomedical materials due to the variety of factors determining their biomedical effects and nanotoxicity. Understanding the interactions of engineered nanomaterials with the biological entities becomes crucial to the further development of nanoscience and nanotechnology. In the past decade, colleagues in our laboratory intensively studied the toxic properties of various kinds of nanomaterials and their chemical mechanisms. In this paper we review the recent advance in the research on the biological effects of engineered nanomaterials and nanosafety issue, by focusing on the studies about representative nanomaterials in our laboratory.
Initial Decomposition of Methanol and Water on In2O3(110): A Periodic DFT Study
Authors: Lin Sen , Xie Daiqian
Published: September 2012

Pure In2O3 is considered as an efficient methanol steam reforming catalyst. Despite of several studies in the past decades, the mechanism of MSR on In2O3 is still not fully understood. In this work, a periodic density functional theory study of the initial dissociation of methanol and water over the In2O3 (110) surface is presented. The activation energy barriers and thermochemistry for several elementary steps are reported. It is found that the energy barriers for OH bond cleavage of both CH3OH and H2O to produce CH3O and OH species at a surface In‐O pair site are very low, indicating that In2O3 (110) can facilely catalyze these two important processes at low temperatures. In addition, the subsequent dehydrogenation of CH3O to CH2O is also found to proceed with a low barrier.
Synthesis and Structure of Supramolecular Compound with Ethyl 2‐(4‐Aminophenoxy)acetate Based on 18‐Crown‐6
Authors: Wang Wenxiang , Sun Suwen , Xiong Rengen
Published: September 2012

The title ammonium compound ethyl 2‐(4‐aminophenoxy)acetate (C10H13NO3, I) and its crown ether inclusion complex {[(C10H14NO3)·(18‐crown‐6)]+[PF6]−, II} (18‐crown‐6=1,4,7,10,13,16‐hexaoxacyclo‐octadecane) were synthesized. The ammonium compound I was determined by 1H NMR, IR and ESI‐MS techiniques. X‐ray crystallography reveals that compound I crystallizes in the triclinic system with space group of P‐1, all the atoms in I are almost coplanar except H, and NH···O hydrogen bonds lead to the formation of one dimensional chain. The rotator‐stator‐like compound II was crystallizes in the centrosymmetric monoclinic system with space group of P21/c. The supramolecular was formed via NH···O hydrogen‐bond interactions. Temperature‐dependent dielectric constants of compound II were measured.
Structural Studies on 4,5‐Disubstituted 2‐Aminoimidazole‐Based Biofilm Modulators that Suppress Bacterial Resistance to β‐Lactams
Authors: Su Zhaoming , Yeagley Andrew A. , Su Rui , Peng Lingling , Melander Christian
Published: September 2012

A library of 4,5‐disubstituted 2‐aminoimidazole triazole amide (2‐AITA) conjugates has been successfully assembled. Upon biological screening, this class of small molecules was discovered as enhanced biofilm regulators through non‐microbicidal mechanisms against methicillin‐resistant Staphylococcus aureus (MRSA) and multidrug‐resistant Acinetobacter baumannii (MDRAB), with active concentrations in the low micromolar range. The library was also subjected to synergism and resensitization studies with β‐lactam antibiotics against MRSA. Lead compounds were identified that suppress the antibiotic resistance of MRSA by working synergistically with oxacillin, a β‐lactam antibiotic resistant to penicillinase. A further structure–activity relationship (SAR) study on the parent 2‐AITA compound delivered a 2‐aminoimidazole diamide (2‐AIDA) conjugate with significantly increased synergistic activity with oxacillin against MRSA, decreasing the MIC value of the β‐lactam antibiotic by 64‐fold. Increased anti‐biofilm activity did not necessarily lead to increased suppression of antibiotic resistance, which indicates that biofilm inhibition and resensitization are most likely occurring via distinct mechanisms.
Relativistic and Non‐Relativistic Electronic Molecular‐Structure Calculations for Dimers of 4p‐, 5p‐, and 6p‐Block Elements
Authors: Höfener Sebastian , Ahlrichs Reinhart , Knecht Stefan , Visscher Lucas
Published: September 2012

We report results of non‐relativistic and two‐component relativistic single‐reference coupled‐cluster with single and double and perturbative triple excitations [CCSD(T)] treatments for the 4p‐block dimers Ga2 to Br2, the 5p‐block dimers In2 to I2, and their atoms. Extended basis sets up to pentuple zeta are employed and energies extrapolated to the complete basis‐set limit. Relativistic and non‐relativistic results for the dissociation energy De are in close agreement with each other and previously published data, provided non‐relativistic or scalar‐relativistic results are corrected for spin–orbit contributions taken from the literature. An exception is Te2 where theoretical results scatter by 0.085 eV. By virtue of this agreement it is unexpected that comparison with the experimental D0 or De dissociation energies (zero‐point vibrational effects are negligible in this context) reveal errors larger than 0.1 eV for Ga2, Ge2, and Sb2. Only relativistic treatments are presented for the 6p‐block cases Tl2 to At2. Sufficient agreement with experimental data is found only for Pb2 and Bi2, the deviation of the computed and experimental D0 values for Po2 is again larger than 0.1 eV. Deviations of 0.1 eV between the computed and experimental D0 values are a major reason for concern and call for additional investigations in both fields to clarify the situation.
Highly Asymmetric Tribenzonaphtho‐Condensed Porphyrazinatozinc Complex: An Efficient Near‐Infrared Sensitizer for Dye‐Sensitized Solar Cells
Authors: Yu Lijuan , Zhou Xiaole , Yin Yinghui , Liu Yuwen , Li Renjie , Peng Tianyou
Published: September 2012

Novel, highly asymmetric zinc phthalocyanine (ZnPc) derivatives (Zn‐tri‐PcNc) containing tribenzonaphtho‐condensed porphyrazine with one carboxyl and three tert‐butyl (tBu) or n‐butoxy (nBuO) peripheral substituents were synthesized by using 6‐carboxymethyl‐2,3‐dicyanonaphthalene and 4‐tBu‐ or nBuO‐phthalonitrile as starting agents. The new, highly asymmetric ZnPc containing tBu groups (Zn‐tri‐PcNc‐2 b) yielded a 3.56 % conversion efficiency in sensitizing TiO2‐based dye‐sensitized solar cells (DSSCs) under simulated AM 1.5G solar irradiation (100 mW cm−2), which is higher than that of the nBuO‐containing analogue Zn‐tri‐PcNc‐3 b (2.20 %). Moreover, Zn‐tri‐PcNc‐2 b displays 60.7 % of the maximum incident monochromatic photon‐to‐current conversion efficiency (IPCE) in the red/near‐IR region, which is much higher than that of Zn‐tri‐PcNc‐3 b (22.9 %), thus highlighting the potential of Zn‐tri‐PcNc‐2 b as a DSSC component.
Suppressing harmonics in four‐quadrant AC‐DC converters with chaotic SPWM control
Authors: Li Hong , Li Zhong , Lin Fei , Zhang Bo
Published: September 2012

In this paper, a new chaotic sinusoidal pulse width modulation (chaotic SPWM) control is proposed and implemented in a four‐quadrant AC‐DC converter for harmonics suppression, where a chaotic carrier plays a key role. Further, the relationship of the harmonic distribution and carrier frequency is derived by analyzing the harmonic components of the AC‐DC converter, which is useful for revealing the operation principle of the chaotic SPWM control for harmonic suppression. Finally, the simulation and experimental results illustrate the effectiveness of the proposed chaotic SPWM control on harmonics reduction. Copyright © 2012 John Wiley & Sons, Ltd.
Electron Temperature Measurement in a Premixed Flat Flame Using the Double Probe Method
Authors: Wild J. , Kudrna P. , Tichý M. , Nevrlý V. , Střižík M. , Bitala P. , Filipi B. , Zelinger Z.
Published: September 2012

The electron temperatures Te were measured using a double probe in a premixed methane flame produced by a calibration burner according to Hartung et al. The experiment was performed at atmospheric pressure. In contrast to other authors, we have managed to find typical nonlinearities corresponding to the retarding electron current region and to calculate electron temperatures using a suitable fit on the basis of the measured characteristics. A Pt‐Rh thermocouple was used to measure temperatures Th corresponding to “heavy” species. Our results indicate that the flame plasma can be considered to be weakly non‐isothermic — Te = (2400–4000) K, Th = (1400–1600) K. On the basis of measurement of the saturated ion current, the number density of the charged particles was estimated at (0.3–3.8) · 1017 m‐3. The trends in Te and Th in dependence on the positions of the probes and thermocouple in the flame differ substantially; this fact has not yet been explained (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deciduoid mesothelioma: Cytologic presentation and diagnostic pitfalls
Authors: Huang Cheng Cheng , Michael Claire W.
Published: September 2012

We report two cases of malignant deciduoid mesothelioma (MDM), a very rare variant of malignant mesothelioma (MM). Case 1: An 18‐year‐old male with no history of asbestos exposure presented with worsening abdominal pain, anorexia, and vomiting after a motor vehicle accident. A CT scan showed small amount of ascites and abdominal mass. An exploratory laparotomy revealed multiple yellow tan, firm nodules on the peritoneum and omentum. He received palliative treatment and died 5 months after the diagnosis. Case 2: A 64‐year‐old female with history of asbestos exposure initially presented with abdominal distension. CT scan showed abdominal mass with a large amount of ascites. A diagnostic laparoscopy revealed multiple peritoneal nodules. She underwent several regimens of chemotherapy over a period of 69 months and is still alive to date. In both cases, features of mesothelial origin were subtle and the smears showed predominantly single cells with marked nuclear atypia. The second case also contained few two‐dimensional loose cell clusters with scalloped or hobnail borders. The clusters often exhibited a pseudoacinar structure surrounding a globular extracellular material. Groups of three to four cells often formed doublets and triplets with cell‐to‐cell windows.

Our results show that MDM may not present with the traditional cytological features described in MM and can manifest with more nuclear pleomorphism resulting in erroneous diagnosis. Recognition of the subtle mesothelial features along with the appropriate ancillary tests is essential for accurate diagnosis. Diagn. Cytopathol. 2013. © 2012 Wiley Periodicals, Inc.
Solid pseudopapillary tumor of the pancreas: ‘Experiences’ and ‘Lessons’ at a tertiary‐care oncology center
Authors: Bal Munita Meenu , Deodhar Kedar , Shrikhande Shailesh , Shukla Parul , Arya Supreeta , Ramadwar Mukta
Published: September 2012

Solid pseudopapillary tumor of the pancreas (SPT) is a rare and fascinating entity of elusive histogenesis and unpredictable biology. It has a peculiar proclivity to afflict young females and involve the pancreatic body‐tail region. Cytology diagnosis of these rare neoplasms remains a challenge. We analyzed the cytology features of all SPT cases diagnosed on fine needle aspiration cytology (FNAC) from 2003 to 2009 along with their histopathology slides. Nineteen consecutive cases were diagnosed as SPT on FNAC. Fifteen out of nineteen cases were confirmed as true SPT on histopathology. Amongst the true SPT, all except one occurred in females. Age ranged from 14 to 50 years. Pseudopapillae bearing stout branches terminating in bulbous tips and enclosing transgressing vessels, separated from a collar of tumor cells by a clear zone of myxohyaline coat were pathognomonic of SPT. Singly dispersed monomorphic tumor cells with bland chromatin formed the second diagnostic component of SPT. Nuclear grooves and hyaline globules were in addition helpful in segregating SPT from its close differentials. In four cases diagnosed as SPT on FNAC, histopathology revealed a different final diagnosis (one case each of paraganglioma, extragastrointestinal stromal tumor, metastatic papillary renal cell carcinoma and inflammatory myofibroblastic tumor). Conversely, one case of SPT had been erroneously diagnosed as neuroendocrine tumor on FNAC. Six cases (40%) developed metastasis; commonest site being liver. In conclusion, cytology in conjunction with clinico‐radiologic findings plays a key role in making a correct diagnosis. Awareness of unique cytomorphological features is important in distinguishing this tumor from its diverse mimics. Diagn. Cytopathol. 2013. © 2012 Wiley Periodicals, Inc.
Value of image‐guided fine‐needle aspiration cytology—A study of 500 cases
Authors: Ghosh Arnab , Ghartimagar Dilasma , Shrestha Manish Kiran , Tiwari P. K. , Narasimhan Raghavan , Talwar O. P.
Published: September 2012

Guided Fine‐Needle Aspiration Cytology (FNAC) as the first line investigation is not only useful in diagnosis of space occupying lesions but can also help in choosing appropriate management. This technique is most useful in diagnosing metastasis but is also helpful in excluding malignancy in some cases. Aim of this study is to analyze the spectrum of cytological diagnosis, adequacy, and clinicoradiological correlation of guided FNAC.

The study was carried out in the departments of pathology and radiology for a period from January 2000 to November 2011. All the data were retrieved from hospital medical record section and departmental data bank and were analyzed.

We have performed a total of 500 FNACs, including 234 under CT guidance and 266 under USG guidance. Among the CT‐guided FNACs, 87.6% (205 cases) had adequate material which included 152 malignant cases, 38 inflammatory cases and 15 benign cases. Among the cases under USG, 91.7% (244 cases) had adequate material comprising of 112 malignant cases, 44 inflammatory cases, and 88 benign lesions. It was noted that increased number of inadequate aspirate was from lesions with smaller size and increased depth. Out of total 264 malignant cases diagnosed on FNAC, 160 cases were identified as malignant on clinical and radiological findings.

Guided FNAC is useful in deep seated lesions as well as in suspicious superficial lesions and is a safe diagnostic tool. If performed properly and correlated well with clinical and radiological findings, FNAC provides correct diagnosis in most cases. Diagn. Cytopathol. 2013;41:1052–1062. © 2012 Wiley Periodicals, Inc.
Foamy gland pancreatic ductal adenocarcinoma diagnosed on EUS‐FNA: A histochemical, immunohistochemical, and molecular report
Authors: Bellevicine Claudio , Malapelle Umberto , Iaccarino Antonino , Schettino Pietro , Napolitano Vincenzo , Zeppa Pio , Troncone Giancarlo
Published: September 2012

The foamy gland pattern (FGP) may impart to pancreatic ductal adenocarcinoma (PDA) a deceptively benign appearance. Thus, its diagnosis on FNA is challenging. A case of PDA with FGP, that was suspected on Diff Quik smears, diagnosed on cell‐block preparation and confirmed by ancillary stains and molecular techniques, is here reported. The diagnostic interpretation of foamy atypical cells on direct smears may benefit from cell block preparation and from ancillary techniques. Diagn. Cytopathol. 2013. © 2012 Wiley Periodicals, Inc.
Primary hydatid cyst of the supraspinatus muscle: Complete removal of the germinal layer and cytodiagnosis by fine‐needle aspiration
Authors: Das Dilip K. , El‐Sharawy Maha , Ayyash Emad H. , Al‐Enezi Nadia A. , Iqbal Jamshed R. , Madda John P.
Published: September 2012

Primary hydatid disease of the skeletal muscle without systemic involvement is rare. The purpose of this report is to document the novel clinical presentation and the interesting facets of fine‐needle aspiration in a case of hydatid disease. It was a case of primary hydatid cyst of the left supraspinatus muscle in an Indian woman living in Kuwait, which was clinically diagnosed as a lipoma. Fine‐needle aspiration (FNA) yielded 2 ml of clear fluid with white particulate material. The cytocentrifuged smears prepared from the aspirated fluid showed many scolices, occasional laminated cyst wall fragments and numerous hooklets. The laminated cyst wall and scolices were PAS positive. Trichrome staining imparted a demon‐head‐like appearance to the scolices. The cytodiagnosis of hydatid cyst was corroborated by histopathological examination of an excised whitish membrane and an irregular cystic fragment, which showed parallel laminations without germinal layer, and skeletal muscle with granulomas and a dense eosinophilic infiltration, respectively. Quantitative serological (indirect hemagglutination) test on blood sample collected 9 days after the excision of the cyst showed insignificant antibody titer to Echinococcus sp. and after 6 weeks the antibodies were completely absent. CT scan of the chest and abdomen performed 7 weeks after removal of cyst showed no evidence of visceral hydatid cyst. Diagn. Cytopathol. 2014;42:268–272. © 2012 Wiley Periodicals, Inc.
Cytologic features of fibrolamellar carcinoma with mucin production: A rare variant of combined hepatocellular‐cholangiocarcinoma
Authors: Rosa Marilin , Mohammadi Amir
Published: September 2012

Fibrolamellar carcinoma (FC) is an uncommon tumor that usually arises in non‐cirrhotic livers of adolescents or young adults. It differs clinically from hepatocellular carcinoma in its better prognosis and lack of gender predilection. Cytologically, the tumor is composed of large polygonal cells with abundant cytoplasm, pleomorphic nuclei, and prominent large nucleoli. A variant of FC with mucinous differentiation has been previously described. These tumors have been regarded as combined hepatocellular cholangiocarcinomas. Herein, we report the case of a 44‐year‐old Asian female with a large liver mass present for approximately two years. Core needle biopsy with imprint cytology demonstrated FC with areas of intracellular mucin. To our knowledge, cytological features of this rare tumor have not been described before. Diagn. Cytopathol. 2014;42:431‐435. © 2012 Wiley Periodicals, Inc.
C‐peptide‐stimulated nitric oxide production in a cultured pulmonary artery endothelium is erythrocyte mediated and requires Zn2+
Authors: Giebink Adam W. , Vogel Paul A. , Medawala Wathsala , Spence Dana M.
Published: September 2012

Background

C‐peptide has been shown to stimulate the production of nitric oxide (NO) in aortic endothelial cells via activation of endothelial nitric oxide synthase (eNOS) through an increased calcium influx. Here, results obtained using cultured bovine pulmonary artery endothelial cells (bPAECs) suggest that C‐peptide does not induce eNOS activation directly in cultured pulmonary artery endothelium. However, C‐peptide has been shown to stimulate the release of ATP from erythrocytes, a well‐documented stimulus of eNOS activity in the pulmonary endothelium. Therefore, studies were performed to examine if C‐peptide can indirectly stimulate NO production in a cultured pulmonary endothelium that is erythrocyte mediated.

Methods

NO production and free intracellular calcium changes were monitored in immobilized bPAECs using specific intracellular fluorescent probes after stimulation with adenosine triphosphate (ATP), calcium ionophore A23187, or C‐peptide. A microfluidic device enabled immobilized bPAECs to interact with flowing erythrocytes in the presence and absence of C‐peptide to determine the role of the erythrocyte in C‐peptide‐stimulated NO production in cultured bPAECs.

Results

ATP and the calcium ionophore stimulate significant increases in both intracellular NO production and influx of free calcium in cultured bPAECs. In contrast, C‐peptide, ranging from physiological to above physiological concentrations, was unable to stimulate NO production or calcium influx in the bPAECs. However, when erythrocytes were pre‐incubated with a mixture containing physiological concentrations of C‐peptide with Zn2+ and haemodynamically pumped beneath bPAECs cultured on a microfluidic device, an 88.6 ± 7.5% increase in endothelial NO production was observed.

Conclusions

C‐peptide does not affect NO production in bPAECs directly but can impact NO production through an erythrocyte‐mediated mechanism. Furthermore, in the absence of Zn2+, C‐peptide does not stimulate this NO production directly or indirectly. These results suggest that C‐peptide, in the presence of Zn2+, may be a determinant in purinergic receptor signalling via its ability to stimulate the release of ATP from erythrocytes. Copyright © 2012 John Wiley & Sons, Ltd.
Axonal dysfunction prior to neuropathy onset in type 1 diabetes
Authors: Arnold Ria , Kwai Natalie , Lin Cindy S.‐Y. , Poynten Ann M. , Kiernan Matthew C. , Krishnan Arun V.
Published: September 2012

Background

The present study was undertaken to determine whether there were changes evident in axonal membrane function prior to the onset of neuropathy in patients with type 1 and type 2 diabetes.

Methods

From a cohort of 110 consecutive referrals, nerve excitability was investigated in 40 diabetic patients without clinical evidence of neuropathy (20 type 1 diabetic patients and 20 type 2 diabetic patients). Groups were matched for gender, disease duration and HbA1c. Studies were also undertaken in two control groups, younger controls and older controls, matched for age and gender with the diabetic cohorts.

Results

Subjects with type 1 diabetes demonstrated significant nerve excitability abnormalities when compared with younger normal controls. Specifically, type 1 subjects showed a significant reduction at multiple time points in both depolarising and hyperpolarising threshold electrotonus. Additionally, the relative refractory period was prolonged (type 1, 3.19 ms; younger normal controls, 3.0 ms; p < 0.05) and superexcitability was reduced (type 1, −23.12%; younger normal controls, −26.37%; p < 0.05), consistent with axonal membrane depolarisation. Correlations were identified in type 1 patients between disease duration and nerve excitability parameters, including the relative refractory period (r = −0.533, p < 0.05). In contrast, only minor non‐specific changes were noted in the type 2 group.

Discussion

This study provides clear evidence of altered axonal function in patients with type 1 diabetes in the absence of clinical neuropathy. These findings suggest that altered axonal membrane potential may precede neuropathy onset in type 1 diabetes and as such may indicate a window of opportunity to intervene and potentially reverse axonal membrane dysfunction before the development of irreversible neuropathy. Copyright © 2012 John Wiley & Sons, Ltd.
Birth weight influences the clinical phenotype and the metabolic control of patients with type 1 diabetes (T1D)
Authors: Benevento Danila , Bizzarri Carla , Patera Ippolita Patrizia , Ravà Lucilla , Schiaffini Riccardo , Ciampalini Paolo , Cianfarani Stefano , Cappa Marco
Published: September 2012

Background

High birth weight has been related to an increased risk of type 1 diabetes (T1D), while suboptimal birth weight (both high and low) has been related to obesity, insulin resistance and type 2 diabetes. Insulin resistance, as a consequence of poor metabolic control, has been described in T1D patients. The aims of the study were to analyse the distribution of birth size for gestational age in a large group of T1D patients and to investigate the effect of birth weight on clinical phenotype.

Methods

Six‐hundred two Caucasian T1D patients were evaluated. Small for gestational age (SGA) and large for gestational age (LGA) were defined as birth weight at <3rd percentile and >97th percentile for gestational age, respectively. Birth weights between the 3rd and 97th percentiles were defined as appropriate for gestational age. The clinical characteristics of small, appropriate for gestational age and large were compared. Multivariable linear regression models were fitted to evaluate the independent effects of birth weight and other covariates (age at T1D onset, gender and T1D duration) on different clinical outcomes (body mass index, HbA1c, insulin requirement, high‐density lipoprotein cholesterol and triglycerides).

Results

Thirteen subjects (2.16%) were small (SGA), and 39 (6.48%) were large (LGA). Daily insulin requirement (U/kg/day) was significantly higher in SGA, while body mass index and HbA1c were increased in LGA. Multivariable linear regression showed a significant negative effect of birth weight on daily insulin requirement (p < 0.001).

Conclusions

Suboptimal birth weight (both high and low) in T1D patients seems to be associated with clinical characteristics suggestive of insulin resistance. Copyright © 2012 John Wiley & Sons, Ltd.
Molecular Networks Based on CN Coordination Bonds
Authors: Karsch Markus , Lund Henrik , Schulz Axel , Villinger Alexander , Voss Karsten
Published: September 2012

This study examines the use of tetrahedral [E(O–C6X4–CN)4]– anions (E = B, Al; X = H, F), which can be synthesized from the reaction of tetrahedral NaBH4/LiAlH4 and HO–C6X4–CN, as anionic linkers for the generation of 2D and 3D crystalline coordination polymer networks. Such polymer networks were obtained by the connection of tetrahedral p‐cyanophenoxy aluminate or borate linkers with monocationic metal centers such as Li+, Na+, Ag+, and Cu+. These studies are specifically focused on the synthesis, structure, and stability of such polymers. Additionally, the perfluorinated O–C6F4–CN linker was used to study electronic influences. Salts bearing the perfluorinated [E(O–C6F4–CN)4]– anion decompose into E(O–C6F4–CN)3 and [O–C6F4–CN]–, which is also observed when a Lewis acid such as B(C6F5)3 is added. Moreover, addition of B(C6F5)3 leads to the formation of molecular‐ion pairs because the cyano groups are now either completely or partly blocked. The structures of M[Al(O–C6H4–CN)4] (M = Li, Ag, Cu), Na[B(O–C6H4–CN)4], and Li[Al(O–C6F4–CN)4] as well as of the decomposition products Na(O–C6F4–CN), (THF)Al[O–C6H4–CN·B(C6F5)3]3 (THF = tetrahydrofuran), Na[(F5C6)3B·O–C6H4–CN·B(C6F5)3], and Li[NC–C6F4–O–Al{O–C6F4–CN·B(C6F5)3}3] are discussed.
Intermolecular Mono‐ and Dihydroamination of Activated Alkenes Using a Recoverable Gold Catalyst
Authors: Medina Florian , Michon Christophe , Agbossou‐Niedercorn Francine
Published: September 2012

A combination of gold chloride organometallic complex and a silver salt was used to catalyze intermolecular hydroamination of activated alkenes, i.e aza‐Michael reactions. The gold‐catalyzed reactions of activated alkenes with nitrogen substrates were investigated and found to afford various mono‐ and dihydroamination products, the latter being rare and original. After flash chromatography, gold NHC catalyst could be recovered as a gold hydroxide NHC complex. When combined with a silver salt, the gold complex lead again to an active hydroamination catalyst.
Stereoselective Synthesis of cis‐Fused Perhydrofuro[2,3‐b]furan Derivatives from Sugar‐Derived Allyl Vinyl Ethers
Authors: Sridhar Perali Ramu , Reddy Gadi Madhusudhan , Seshadri Kalapati
Published: September 2012

A stereoselective methodology has been developed for the construction of cis‐fused perhydrofuro[2,3‐b]furans, via 3‐C‐branched glycal derivatives, involving Claisen rearrangement of sugar‐derived allyl vinyl ethers, followed by a one‐pot ozonolysis and acid‐mediated acetalization. The methodology was used for the stereoselective synthesis of the P2 ligand in the recently FDA approved HIV protease inhibitor darunavir (Prezista). The methodology was also successfully used for the synthesis of cis‐fused perhydro‐5‐oxofuro[2,3‐b]furan derivatives.
Expeditious, Metal‐Free, Domino, Regioselective Synthesis of Highly Substituted 2‐Carbonyl‐ and 2‐Phosphorylfurans by Formal [3+2] Cycloaddition
Authors: Raimondi Wilfried , Dauzonne Daniel , Constantieux Thierry , Bonne Damien , Rodriguez Jean
Published: September 2012

2‐Functionalized furans are very easily synthesized by exploiting the dual nucleophilic character of 1,2‐dicarbonyls and the dual electrophilic properties of (2‐chloro‐2‐nitroethenyl)benzenes in a one‐pot, formal [3+2] cycloaddition. Using a base (DBU), the desired trisubstituted heterocycles were formed rapidly (10–30 min) in good to excellent yields (51–92 %), and this versatile, metal‐free methodology was applied to the synthesis of 2‐acyl‐ and 2‐carboalkoxyfurans and furan‐2‐carboxamides. Additionally, by using 2‐ketophosphonate derivatives as dinucleophiles, the corresponding 2‐phosphorylfurans were formed in good yields (53–74 %).
Evaluating channel response to an extreme sedimentation event in the context of historical range of variability: Upper Colorado River, USA
Authors: Rathburn Sara L. , Rubin Zan K. , Wohl Ellen E.
Published: September 2012

In May 2003, a breach in a large irrigation ditch within Rocky Mountain National Park (RMNP) initiated a debris flow that entered Lulu Creek and the Colorado River, where 36 000 m3 of sediment substantially altered channel forms and processes. We present a proof of concept to understand whether the 2003 disturbance is within the historical range of variability (HRV), and whether the recovery potential of the system is sufficient to adapt to the disturbance. Flow and sediment regimes, and channel morphology and stability were monitored on Lulu Creek and the Colorado River from 2004 to 2011. Dominant channel response following the debris flow within Lulu Creek included step development, bed armoring, and channel widening. Step height‐to‐length ratios (H/L) for three reaches on Lulu Creek are outside the HRV of reference channels, with one reach approaching reference conditions. Erosion of approximately 23% of the debris fan volume occurred as a result of the long duration 2011 peak flow. Sediment within the Lulu Creek fan will persist for ~30–190 years, assuming current maximum and mean removal rates. Planform changes on the Colorado River since the debris flow include an increase in single‐thread geometries, with braided reaches where bar deposition occurred. Bedload transport and grain‐size analysis of bedload indicate translational spreading of a sand wave front with a dispersive component in steeper reaches. Lulu Creek is returning to a condition of natural variability, but the Colorado River is outside the HRV expected for steep‐gradient, pool‐riffle channels. Applying HRV to a situation where management questions require a longer term perspective, and pre‐disturbance baseline data are limited, is a useful approach. The HRV analysis facilitates a better understanding of site variability and delineates the range of possibilities of channel form and process to achieve management goals. Copyright © 2012 John Wiley & Sons, Ltd.
Aeolian sediment transport and morphologic change on a managed and an unmanaged foredune
Authors: Jackson Nancy L. , Nordstrom Karl F.
Published: September 2012

Sediment transport and short‐term morphologic change were evaluated at a site where sand fences are deployed and the beach is raked (Managed Site) and a site where these human adjustments are not practiced (Unmanaged Site). Data were gathered across the seaward portion of a low foredune when winds blew nearly shore‐normal at mean speeds 8.9 to 9.3 m s‐1. Data from traps revealed sediment transport rates at unvegetated portions of the foredune crest (40.2 to 43.5 kg m‐1 h‐1) were greater than on the backshore (4.9 to 11.2 kg m‐1 h‐1) due to onshore decreases in surface moisture and speed‐up of the wind passing over the foredune. Data from erosion pins indicate sediment input to the dune was 1.48 m3 m‐1 alongshore at the Managed Site and 1.25 m3 m‐1 at the Unmanaged Site. The Unmanaged Site had deposition at the dune toe, erosion at mid‐slope, and deposition at the crest. Deposition occurred at mid‐slope on the Managed Site near a partially buried (0.58 m high) fence with a porosity of about 65%. Deposition at partially buried wrack on the upper backshore and dune toe at the Unmanaged Site was about twice as great as deposition in this zone at the Managed Site. Results indicate that: (1) the seaward slope of the foredune can be a more important source of sand to the lee of the crest than the beach; (2) wrack near the toe can decrease transport into the foredune; (3) a scour zone can occur on the foredune slope above the wrack line; (4) a fence placed in this location can promote deposition and offset scour, but fences can restrict delivery of sediment farther inland. Evaluation of alternative configurations of fences and strategies for managing wrack is required to better determine the ways that humans modify foredunes. Copyright © 2012 John Wiley & Sons, Ltd.
Macroturbulent coherent structures in an ice‐covered river flow using a pulse‐coherent acoustic Doppler profiler
Authors: Demers Sylvio , Buffin‐Bélanger Thomas , Roy André G.
Published: September 2012

The aim of this work is to compare macroturbulent coherent structures (MCS) geometry and organization between ice covered and open channel flow conditions. Velocity profiles were obtained using a Pulse‐Coherent Acoustic Doppler Profiler in both open channel and ice‐covered conditions. The friction imposed by the ice cover results in parabolic shaped velocity profiles. Reynolds stresses in the streamwise (u) and vertical (v) components of the flow show positive values near the channel bed and negative values near the ice cover, with two distinctive boundary layers with specific turbulent signatures. Vertically aligned stripes of coherent flow motions were revealed from statistics applied to space‐time matrices of flow velocities. In open channel conditions, the macroturbulent structures extended over the entire depth of the flow whereas they were discontinued and nested close to the boundary walls in ice‐covered conditions. The size of MCS is consequently reduced in scale under an ice cover. The average streamwise length scale is reduced from 2.5 to 0.4Y (u) and from 1.5 to 0.4Y (v) where Y is the flow depth. In open channel conditions, the vertical extent of MCS covers the entire flow depth, whereas the vertical extent was in the range 0.58Y–1Y (u) and 0.81Y–1Y (v) in ice‐covered conditions. Under an ice cover, each boundary wall generates its own set of MCS that compete with each other in the outer region of the flow, enhancing mixing and promoting the dissipation of coherent structures. Copyright © 2012 John Wiley & Sons, Ltd.
Performance analysis of a novel antenna array calibration approach for direction finding systems
Authors: Inserra D. , Tonello A.M.
Published: September 2012

This paper addresses the problem of the direction of arrival (DoA) estimation in the presence of an uncalibrated array, i.e. when phase offset, carrier frequency offset and phase noise occur among the array signals. The method that we propose consists in the use of a particular antenna array that comprises the elements for the DoA estimation and a common antenna that is shared with a splitter among the receivers. The signal that impinges on the common antenna is acquired by every receiver and allows the estimation of the phase ambiguity. After the calibration step is performed, analogue switches select the array elements for the DoA estimation. A method that enables the phase ambiguity estimation is presented, and several simulated performance results are illustrated. Furthermore, we show the effect on calibration due to the presence of different carrier frequency offsets among the receivers and propose an approach for their compensation. The presence of phase noise is also considered and its effect is analysed.Copyright © 2012 John Wiley & Sons, Ltd.
The frequency of previously undetectable deletions involving 3′ Exons of the PMS2 gene
Authors: Vaughn Cecily P. , Baker Christine L. , Samowitz Wade S. , Swensen Jeffrey J.
Published: September 2012

Lynch syndrome is characterized by mutations in one of four mismatch repair genes, MLH1, MSH2, MSH6, or PMS2. Clinical mutation analysis of these genes includes sequencing of exonic regions and deletion/duplication analysis. However, detection of deletions and duplications in PMS2 has previously been confined to Exons 1–11 due to gene conversion between PMS2 and the pseudogene PMS2CL in the remaining 3′ exons (Exons 12–15). We have recently described an MLPA‐based method that permits detection of deletions of PMS2 Exons 12–15; however, the frequency of such deletions has not yet been determined. To address this question, we tested for 3′ deletions in 58 samples that were reported to be negative for PMS2 mutations using previously available methods. All samples were from individuals whose tumors exhibited loss of PMS2 immunohistochemical staining without concomitant loss of MLH1 immunostaining. We identified seven samples in this cohort with deletions in the 3′ region of PMS2, including three previously reported samples with deletions of Exons 13–15 (two samples) and Exons 14–15. Also detected were deletions of Exons 12–15, Exon 13, and Exon 14 (two samples). Breakpoint analysis of the intragenic deletions suggests they occurred through Alu‐mediated recombination. Our results indicate that ∼12% of samples suspected of harboring a PMS2 mutation based on immunohistochemical staining, for which mutations have not yet been identified, would benefit from testing using the new methodology. © 2012 Wiley Periodicals, Inc.
The value of ethyl cysteinate dimer single photon emission computed tomography in predicting antidepressant treatment response in patients with major depression
Authors: Hanada Hiroaki , Imanaga Junko , Yoshiiwa Aoi , Yoshikawa Tomoya , Tanaka Yoshihiro , Tsuru Jusen , Inoue Ayako , Ishitobi Yoshinobu , Okamoto Shizuko , Kanehisa Masayuki , Maruyama Yoshihiro , Ninomiya Taiga , Higuma Haruka , Isogawa Koichi , Kawasaki Tsuyoshi , Fujioka Toshio , Akiyoshi Jotaro
Published: September 2012

Objective

The purpose of this study is to examine whether the reversal of compromised regional cerebral blood flow (rCBF) in older patients with major depressive disorder (MDD) is dependent on specific parameters of selective serotonin reuptake inhibitor (SSRI) treatment and to examine the efficacy of such treatment.

Methods

Forty‐five patients with moderate MDD were studied following 8 weeks of treatment with SSRIs. Twelve patients displayed a positive response to SSRIs, whereas 33 patients did not respond to SSRI treatment. A comparison group of 30 healthy volunteers was also studied. The age of all participants was greater than 50 years. Age, gender, and the Hamilton Rating Scale for Depression scores were examined. The rCBF was assessed using 99mTc‐ethyl cysteinate dimer single photon emission computed tomography after SSRI treatment.

Results

The rCBF levels in the right middle frontal cortex in non‐responsive MDD patients were lower compared with responsive MDD patients. Compared with healthy controls, non‐responders had significantly lower rCBF levels in the bilateral middle frontal cortex and insula and had significantly higher rCBF levels in the bilateral inferior frontal cortex and left middle temporal cortex. Compared with healthy controls, responders had significantly higher rCBF levels in the left inferior frontal, middle temporal, precentral, and fusiform gyrus. We found no changes in single photon emission computed tomography between pre‐treatment and post‐treatment stages for the responders to SSRI treatment.

Conclusion

Hypoperfusion in older, non‐responsive MDD patients was primarily localized in the middle frontal cortex. It is possible that the responders to SSRI treatment at baseline already displayed higher rCBF values in the frontal regions. Copyright © 2012 John Wiley & Sons, Ltd.
Neck metastases in oropharyngeal cancer: Necessity and extent of bilateral treatment
Authors: Dziegielewski Peter T. , O'Connell Daniel A. , Szudek Jacek , Barber Brittany , Joshi Arjun , Harris Jeffrey R. , Seikaly Hadi
Published: September 2012

Background

Bilateral neck treatment in oropharyngeal squamous cell carcinoma (OPSCC) is controversial. This study determined the rate of bilateral neck metastases in OPSCC and formulated a neck treatment algorithrm for OPSCC.

Methods

In all, 212 consecutive patients with OPSCC underwent ipsilateral level I–V and contralateral I–III or I–V neck dissections. Pathology results were used to identify factors predicting bilateral neck metastases.

Results

A total of 171 patients (81%) had ipsilateral and 41 patients (24%) bilateral neck metastases. Multivariate logistic regression found cT4 and ≥cN2a significantly associated with contralateral neck metastases (p < .05). However, tumor site was not predictive (p > .05). High‐risk pathology features predicted contralateral neck disease (p < .05). cN0 and cN1 necks were unlikely to harbor disease in level V (<5%). Both 2‐ and 5‐year contralateral neck recurrence rates were 1% and 2%.

Conclusions

Bilateral neck disease in OPSCC is more common than once thought. Patients with OPSCC with cT4 or cN2a+ would benefit from bilateral neck treatment. Posttreatment high‐risk features should guide treatment escalation. © 2012 Wiley Periodicals, Inc. Head Neck 35: 1461–1467, 2013
Roving revisited, towards an optimum throughfall sampling design
Authors: Ritter Axel , Regalado Carlos M.
Published: September 2012

Additional aspects regarding the optimum fixed and roving sampling techniques, to those already explored in a previous authors’ throughfall study, are further investigated here. The roving technique consists in the random repositioning, with a frequency fr, of N throughfall gauges among M positions (M > N), oppositely to the fixed or stationary arrangement where N = M. Both fixed and roving optimum sampling techniques of 100 monitored throughfall events sampled with 200 fixed gauges under a semideciduous tropical rain forest in Panama were investigated by means of Monte‐Carlo numerical experiments. Mean dispersion was shown to be always smaller in the roving versus the fixed gauge arrangement, independently of the relocation frequency studied (fr = 0.1, 0.2, 0.5, 1), such that all roving schemes with N ≥ 50 gauges lay within ±5% of the mean cumulative throughfall. Results indicated that a low variability, high precision, and accuracy are obtained with a modest relocation frequency fr = 0.2 (i.e. a relocation every five episodes of the original 100 measured events) and N = 30 roving gauges, with no significant improvement worth the extra field work beyond fr > 0.2 and N >30. Only by increasing the number of roving positions from M < < 200 to M = 200, the precision and accuracy of the mean estimate were improved without comprising additional labour. Hence, a roving sampling scheme which relocates gauges over completely new fresh sites each roving cycle is recommended for future throughfall studies. Finally, we designed an a priori sampling strategy which permitted us to conclude that using only the first 20 out of the total 100 measuring events, for the remaining 80 throughfall field measurements, N = 40 roving gauges (i.e. five time less than the originally 200 gauges displayed) would have been sufficient for ensuring ≤5% error, expressed as percentage of the mean cumulative throughfall. Copyright © 2012 John Wiley & Sons, Ltd.