bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis of thioesters in an ion trap
Authors: Cullen Matthew , Miles Deborah , Rothwell Arlene , Bonham Connie , Wood Karl V. , Cushman Mark 
Published: March 2008

AbstractThe alkenyldiarylmethanes are a class of non‐nucleoside reverse transcriptase inhibitors that are currently being developed as potential antivirals for the treatment of HIV infection and AIDS. As part of our continuing investigations on the alkenyldiarylmethanes, a series of thioester analogues were prepared in an effort to improve upon the metabolic stability of the parent lead compound. Hydrolysis of the thioester moieties was consistently observed during ion trap electrospray ionization (ESI) mass spectrometry to the extent that the parent molecular ion was weak in intensity or simply could not be detected. The same hydrolysis observations were also made when the analogues were analyzed by ion trap electron impact (EI) ionization, indicating the hydrolysis event was the result of the ion trap and not ionization technique. Ion‐trap‐mediated hydrolysis has been observed previously in prior alkenyldiarylmethane studies and prevented characterization of certain intermediates; thus, we wished to investigate whether modifying instrument parameters and protocols affected the instrument‐mediated hydrolysis event. Unfortunately, varying the maximum injection time and the number of microscans performed, independent of each other, had little effect on the intensities of the parent ions [MH+] or the hydrolysis products]MH+HSCH3]. Copyright © 2008 John Wiley & Sons, Ltd.
Rapid identification of differentiation markers from whole epithelial cells by matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry and statistical analysis
Authors: Marvin‐Guy Laure F. , Duncan Peter , Wagnière Sandrine , Antille Nicolas , Porta Nadine , Affolter Michael , Kussmann Martin 
Published: March 2008

AbstractMatrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI‐TOFMS) was applied to identify markers for cellular differentiation. The differentiation of a human colon epithelial carcinoma T84 cell line was monitored over a period of 28 days by transepithelial electrical resistance (TER) measurements, alkaline phosphatase (AP) assay, and MALDI‐TOF mass spectral fingerprints combined with statistical analysis. MALDI‐MS generated specific mass spectral fingerprints characteristic of cell differentiation. Twenty‐two ions were selected as diagnostic signals of fully differentiated T84 cells. Ten protein ion signals, detected by MALDI‐MS and validated by statistical analysis, were proposed as T84 cell differentiation markers. Among these signals, ubiquitin was identified as a T84 cell differentiation marker by nanospray liquid chromatography/tandem mass spectrometry (nanoLC/MS/MS). Moreover, depending on the concentration of the cells seeded on the growth support, it was possible to predict the timing of the exponential phase and of cellular differentiation by MALDI‐MS‐derived marker ions. MALDI‐TOFMS was compared to other methods for the determination of cellular differentiation: TER measurements are rapid but yield limited information as to the cellular differentiation state. AP assays are more specific for the differentiation state but take more time. By contrast, MALDI‐MS has been found to be a fast, sensitive and precise method for cell differentiation assessment and provides the opportunity for multiplexing and high throughput. Moreover, the consumable costs per assay are very low. Copyright © 2008 John Wiley & Sons, Ltd.
Determination of wettability of surface‐modified hot‐embossed polycarbonate wafers used in microfluidic device fabrication via XPS and ToF‐SIMS
Authors: Tarik Baytekin H. , Wirth Thomas , Gross Thomas , Treu Dieter , Sahre Mario , Theisen Janko , Schmidt Martin , Unger Wolfgang E. S. 
Published: March 2008

AbstractThe wettability of the surfaces inside the microchannels of a microfluidic device is an important property considering a liquid flows through them. Contact angle measurements usually applied to test the wettability of surfaces cannot be used for an analysis of microchannel walls within microfluidic devices. A workaround is the use of surface analytical methods, which are able to reach points of interest in microchannels and may provide information on the surface chemistry established there. In calibrating these methods by using flat polymer wafers, where the contact angle can be measured as usual, data measured in real microchannels can be evaluated in terms of wetting properties. Reference wafers of bisphenol‐A polycarbonate, a polymeric material that is often used in fluidic microdevice fabrication, were treated under different oxygen plasma conditions. The modified surfaces were characterized by using XPS, time of flight (ToF)‐SIMS and atomic force microscope (AFM). Surface chemistry and surface topography have been correlated with contact angle measurements. In addition, effects of ageing or rinsing after plasma treatment have also been investigated. Copyright © 2008 John Wiley & Sons, Ltd.
Psychosocial factors and gender as predictors of symptoms associated with sick building syndrome
Authors: Kinman Gail , Griffin Miriam 
Published: March 2008

AbstractSick building syndrome (SBS) refers to a cluster of symptoms that typically worsen when employees are at work and diminish when they leave. A higher prevalence of symptoms is frequently observed among female employees. Although its aetiology is debated, evidence suggests that psychosocial factors might be at least as important as features of the working environment in predicting SBS symptoms. Utilizing a sample of 346 office‐based employees (55 per cent female) located in five buildings with no known environmental problems, this study examined job control, job satisfaction, work‐related mood and negative affectivity as predictors of self‐reported symptoms typical of SBS. The role played by gender in symptom‐reporting was also investigated. Findings revealed that employees who experienced more symptoms reported significantly less job control and job satisfaction and more work‐related depression and anxiety. A positive relationship was also observed between symptom‐reporting and negative affectivity. In contrast to previous research, no gender differences were observed in the prevalence of self‐reported symptoms, but men and women differed in the predictors of symptoms and the proportion of variance explained. The findings suggest that demographic and psychosocial factors, as well as features of the objective physical environment, should be considered in future investigations of SBS. Copyright © 2008 John Wiley & Sons, Ltd.
Die Al Mak Nimir Bridge über den Blauen Nil in Khartoum
Authors: Haumer Wolfram , Gebert Gregor , Reichelt Andreas , Schülke Jens , El‐Dawi Khalid 
Published: March 2008

AbstractDie Al Mak Nimir Bridge befindet sich im Stadtzentrum der Sudanesischen Hauptstadt Khartoum. Sie verbindet die beiden Stadteile Khartoum und Khartoum North über den Blauen Nil, der an dieser Stelle etwa 450 m breit ist. Die Brücke, die eine Gesamtlänge von 642,5 m und eine Breite von 22 m aufweist, wurde in nur zweijähriger Bauzeit durch eine türkische Baufirma errichtet und im Oktober 2007 dem Verkehr übergeben. Große Teil e der Planung und die Bauüberwachung wurden durch das deutsche Ingenieurbüro Schüßler‐Plan als Consultant des Bauherrn erbracht.Das Bauwerk ist in Stahlverbundbauweise mit Regelstützweiten von 50 m und einem Hauptfeld von 80 m konzipiert. Bei konstanter Bauhöhe des Brückendecks wird im Bereich des Hauptfeldes eine besondere Lösung erforderlich. Gewählt wurde eine Überspannung durch Schrägseile, die an jeweils zwei außen stehenden Stahlpylonen angreifen. Zum Einsatz kamen Litzenbündel, die am Pylon über einen Sattelpunkt geführt werden. Eine besondere Herausforderung stellte das regelmäßig wiederkehrende Hoch‐wasser des Nils mit bis zu 7 m Höhenunterschied des Wasserspiegels dar. Für die Montage der ca. 3400 t schweren Stahlkonstruktion wurde daher erstmals im Sudan das Taktschiebeverfahren angewendet.Der Aufsatz beschreibt aus Sicht des Consultant den Entwurf mit seinen statischen und konstruktiven Besonderheiten und geht im zweiten Teil auf die Bauausführung ein, die unter schwierigen Randbedingungen zu realisieren war.
Neubau des Kaiserstegs über die Spree in Berlin
Authors: Krone Martin , Reinke Klaus‐Dieter 
Published: March 2008

AbstractDer historische Kaisersteg wurde 1898 als 3‐feldrige, sehr filigrane Bogen‐/Hängewerkkonstruktion mit zwei Strompfeilern und einer Länge von 172 m eröffnet und diente den Mitarbeitern der AEG zur direkten Verbindung vom Bahnhof Schöneweide zum Kabelwerk Oberspree. Zum Ende des 2. Weltkrieges wurde das Brückenbauwerk durch die Waffen‐SS gesprengt und nach Kriegsende nicht wieder aufgebaut. Im Zuge eines Neuordnungsprogramms für das Stadtgebiet Schöneweide wurde ein Ersatzneubau des Kaiserstegs vorgesehen. Für die Planung des Ersatzneubaus waren insbesondere die Anforderungen der Schifffahrt mit einem freizuhaltenden Lichtraumprofil von 75,00 m – 5,25 m und einer außermittigen Lage des Fahrbandes zu berücksichtigen. Unter diesen Randbedingungen war abweichend von der historischen Brückenkonstruktion die Ausführung nur eines Strompfeilers möglich. Das Bauwerk wurde daher als schrägseilverspannter, 2‐Feldträger mit Stützweiten von 48,3 m – 92,0 m und einem ca. 30m hohen Pylon geplant. Im September 2007 wurde nach 2‐jähriger Bauzeit der Kaisersteg als Fußgänger‐ und Radwegbrücke eröffnet. In folgendem Aufsatz wird über Aspekte der Ausführungsplanung und Bauausführung berichtet.
Beulverhalten gedrückter Kastenprofile mit verschiedenen Steifen
Authors: Shigematsu Tsunemi , Ohga Mitao , Hara Takasi 
Published: March 2008

AbstractEs wird eine analytische Methode zum linearen Beulproblem von Kastenprofilen mit Platten‐, Trapezsteifen und L‐förmigen Steifen vorgestellt. Mit Hilfe des Übertragungsmatrizenverfahrens konnte eine genaue Lösung für das Verzweigungsproblem von gedrückten Kastenprofilen mit Steifen gewonnen werden. Als Ergebnisse werden im folgenden Beitrag zwei unterschiedliche Beulverhalten und ein Knickverhalten vorgestellt. Bei dem ersten Beulphänomen tritt eine Beulform auf, so dass an jeder Stelle einer Versteifung im Kastenquerschnitt ein Knotenpunkt liegt. Als zweites Phänomen tritt eine Beulform jeder einzelnen Platte auf, aus denen sich das Kastenprofil zusammensetzt.
Attitudes of Medical Students toward Careers in General Surgery
Authors: Tambyraja Andrew L. , McCrea Caroline A. , Parks Rowan W. , Garden O. James 
Published: March 2008

AbstractBackgroundChanges to general surgical undergraduate curricula, alongside changes in work force and postgraduate training, may be associated with a decline in interest in surgical careers. This study examines the attitudes of students toward surgical training and their career intentions.MethodsA prospective, questionnaire‐based survey was submitted to final year students at the end of their general surgery attachment over a single academic year at a UK medical school. Career ambitions and reasoning were assessed.ResultsOf 223 eligible students, 193 (87%) completed the questionnaire. There were 118 (61%) females and 75 (39%) males with a median (range) age of 23 (21–41) years. Ninety‐eight (51%) respondents undertook their placement at a Teaching Hospital, whereas 93 (41%) were attached to a District General Hospital. One‐hundred forty‐three (74%) students felt that a four‐week attachment had given them a satisfactory exposure to General Surgery, and 36 (19%) disagreed. Sixty‐eight (53%) students were unable to select a single specialty that they would most like to pursue as a future career. Of the remainder, 23 (12%) chose general surgery, 24 (12%) chose general medicine, and 22 (11%) chose general practice. Seventy‐eight (40%) students would consider a career in general surgery, and 75 (39%) would not; 40 (29%) were undecided. The two most popular attractions to general surgery were challenging postgraduate training and highly regarded career esteem. The two most common disincentives were family considerations and the sacrifice of personal time.ConclusionsFewer than half of the final year medical students surveyed were willing to consider general surgery as a future career choice. Potential disincentives should be targeted to promote recruitment into the specialty
High Success Rate of Parathyroid Reoperation may be Achieved with Improved Localization Diagnosis
Authors: Hessman Ola , Stålberg Peter , Sundin Anders , Garske Ulrike , Rudberg Claes , Eriksson Lars‐Gunnar , Hellman Per , Åkerström Göran 
Published: March 2008

AbstractIntroductionBecause of the difficulty of reoperative parathyroid surgery, preoperative imaging studies have been increasingly adopted. We report the use of consistently applied localization diagnosis to yield high success rates in parathyroid reoperations.MethodsParathyroid reoperation was performed after previous parathyroid surgery in 144 patients with nonmalignant hyperparathyroidism (HPT) between 1962 and 2007. From the year 2000, 46 patients who underwent parathyroid reoperation and 14 patients who were subjected to thyroid surgery before primary parathyroid operation were investigated with sestamibi scintigraphy (MIBI), 11C‐methionine PET/CT (met‐PET), surgeon‐performed ultrasound (US), US‐guided fine‐needle aspiration biopsy (US‐FNA), and selective venous sampling (SVS) with rapid PTH (Q‐PTH) analyses. When imaging was considered adequate, additional studies were generally not obtained.ResultsReversal of hypercalcemia was achieved by reoperation in 134 of 144 (93%) of all patients with previous parathyroid surgery. In patients operated from year 2000, MIBI had 90% sensitivity and 88% predictive value, met‐PET 79% sensitivity and 87% predictive value, and US 72% sensitivity and 93% predictive value. SVS with Q‐PTH analyses provided accurate localization or regionalization in 11 of 11 recently selected patients. Q‐PTH analyses in fine‐needle aspirations verified parathyroid origin of excised specimens, and intraoperative Q‐PTH helped decide when operations could be terminated. In patients subjected to the algorithm of imaging procedures, reversal of hypercalcemia and apparent cure was obtained after the reoperation in 45 of 46 patients with previous parathyroid surgery, implying a success rate of 98%, and in all patients with previous thyroid surgery.ConclusionsReoperative parathyroid surgery is challenging. Results can be improved by consistently applied sensitive methods of preoperative imaging, and reoperative procedures may then achieve nearly the same success rates as primary operations.
Syntheses and Characterization of Some Cationic Surfactants
Authors: Shehata H. A. , El‐wahab A. A. Abd , Hafiz A. A. , Aiad I. , Hegazy M. A. 
Published: March 2008

AbstractA series of novel cationic surfactants were synthesized from the quaternization of triethyl amine and various long chain alkyl halide. The chemical structure of the prepared compounds was confirmed using elemental analysis, FTIR and 1H‐NMR spectra. The physical properties of the synthesized surfactants including, electrical conductivity, critical micelle concentration, (CMC) and the degree of ionization of the micelle, (β) were studied. The thermodynamic parameters of micelle formation, standard free energy ΔGm°, enthalpy ΔHm°, and entropy ΔSm° were calculated. The results of the surface parameter determination were correlated with their chemical structures. It was found that the hydrocarbon chain length is the main factor which has an effect on the value of the thermodynamic parameters.
Structural Importance of the Acyl Group in Substrate Specificity of Purified Bovine Lysophospholipase D
Authors: Liu Xi‐Wen , Sok Dai‐Eun , Yook Hong‐Sun , Sohn Cheon‐Bae , Ly Sun Yung , Kim Mee Ree 
Published: March 2008

AbstractThe structural importance of the acyl group in lysophosphatidylcholine (LPC) as substrate of purified bovine lysophospholipase D (lysoPLD) was investigated. Among LPCs with saturated acyl chains, the Km value decreased according to the length of the acyl chain (C12–C16) up to the palmitoyl group, while the Vm value showed no remarkable change. But, the extension of the acyl size to C18, as observed with 1‐stearoyl LPC (Km, 8.5 mM), rather resulted in a remarkable increase in the Km value. Meanwhile, the introduction of one double bond in the C18 saturated acyl chain led to a remarkable reduction in the Km value, as observed with 1‐oleoyl LPC (Km, 0.48 mM). Furthermore, 1‐linoleoyl LPC (Km, 56 μM) with two double bonds exhibited a smaller Km value than 1‐oleoyl LPC, suggesting that the unsaturation degree might be important in augmenting the binding affinity of LPCs. A similar phenomenon was also observed with 1‐arachidonoly LPC (Km, 79 μM) or 1‐docosahexaenoyl LPC (Km, 36 μM). Overall, the order of catalytic efficiency (Vm/Km value) of those LPCs seemed to be affected by the Km value rather than the Vm value, which differed by at most threefold among LPC derivatives. Next, the introduction of a hydroperoxide group into 1‐linoleoyl‐LPC or 1‐arachidonoyl LPC led to a further reduction in Km values (1‐hydroperoxylinoleoyl LPC, 26 μM; 1‐hydroperoxyarachidonoyl LPC, 33 μM), accompanied by a further increase in the Vm/Km values. Additionally, phosphatidylcholines (PCs) with an oxidized acyl chain at sn‐2 position were found to be efficient as 1‐palmitoyl LPC as substrates of lysoPLD. Taken together, the catalytic efficiency of LPCs or oxidized PCs as substrates of lysoPLD seems to be determined by the property of the acyl chain, length of the acyl chain, unsaturation degree and oxidation status.
Hepatic and Adipose Tissue Depot‐Specific Changes in Lipid Metabolism in Late‐Onset Obese (LOB) Rats
Authors: Frick Fredrik , Hume Randip , Robinson Iain C. , Edén Staffan , Oscarsson Jan 
Published: March 2008

AbstractTransgenic Late‐onset OBesity (LOB) rats slowly develop a male‐specific, autosomal dominant, obesity phenotype with a specific increase in peri‐renal white adipose tissue (WAT) depot and preserved insulin sensitivity (Bains et al. in Endocrinology 145:2666–2679, 2004). To better understand the remarkable phenotype of these rats, the lipid metabolism was investigated in male LOB and non‐transgenic (NT) littermates. Total plasma cholesterol (C) levels were normal but total plasma triacylglycerol (TAG) (2.8‐fold) and hepatic TAG content (25%) was elevated in LOB males. Plasma VLDL‐C and VLDL‐TAG levels were higher while plasma apoB levels were 60% lower in LOB males. Increased hepatic TAG secretion explained the increased VLDL levels in LOB males. The hepatic gene expression of FAS, SCD‐1, mitochondrial (mt)GPAT, and DGAT2 was up‐regulated in both old obese and young non‐obese LOB rats. Lipoprotein lipase (LPL) activity in heart and epididymal white adipose tissue (WAT) was unchanged, while LPL activity was increased in peri‐renal WAT (30%) and decreased in soleus muscle (40%). Moreover, FAS, SCD‐1 and DGAT2 gene expression was increased in peri‐renal, but not in epididymal WAT. Basal lipolysis was reduced or unchanged and β‐adrenergic stimulated lipolysis was reduced in WAT from both old obese and young non‐obese LOB rats. To summarize, the obese phenotype of LOB male rats is associated with increased hepatic TAG production and secretion, a shift in LPL activity from skeletal muscle to WAT, reduced lipolytic response in WAT depots and a specific increase in expression of genes responsible for fatty acid and TAG synthesis in the peri‐renal depot.
Use of complementary and alternative medicine by patients attending a head and neck oncology clinic
Authors: Shakeel M , Newton J R , Bruce J , Ah-See K W 
Published: March 2008

AbstractIntroduction:Within the United Kingdom, there are 50 000 practitioners of complementary and alternative medicine, with five million people consulting these practitioners yearly. The aim of this study was to explore the use of such therapies by patients attending a head and neck oncology clinic in Aberdeen.Method:Questionnaires were distributed to 200 patients over an eight-week period. The questionnaire consisted of questions regarding: demographic factors; 48 listed herbal preparations and alternative therapies; reasons for their use; and opinions on their efficacy.Results:One hundred and thirty-eight patients completed the questionnaires. Fifty per cent (69/138) of respondents had used complementary and alternative medicine previously, with 26 per cent having used it in the preceding year. Fifty-five per cent of respondents learned about complementary and alternative medicine use from friends, and the majority obtained such medicines by purchasing from a shop. Fifty per cent (34/69) of respondents stated that their family physician was unaware of their use of complementary and alternative medicine.Conclusion:All medical practitioners should be aware of increasing complementary and alternative medicine usage by the United Kingdom population, and should be able to counsel patients appropriately.
Another reason for intra-operative imaging during cochlear implantation
Authors: Viccaro M , De Seta E , Covelli E , Marvaso V , Filipo R 
Published: March 2008

AbstractObjective:We report a case of a rare cochlear implant complication: the introduction of the electrode array into the superior semicircular canal, with intra-operative measurements of neural response reactions suggesting reasonable functioning of the implant.Case report:A two-year old patient affected by congenital, profound, sensorineural deafness underwent bilateral cochlear implantation at the ENT clinic of the ‘La Sapienza’ University of Rome. Two Clarion 90k devices were implanted, and electrophysiological and radiological checks were performed. After the introduction of the array in the right side, neural response imaging was performed, and a neural potential was found only on two apical electrodes, at a stimulation intensity of 431 clinical units. The situation differed on the left side, where neural response imaging was present at a stimulation intensity of 300 clinical units on the two electrodes tested (one apical electrode (number three), and one middle electrode (number nine)). Intra-operative radiological assessment with a transorbital plain films was performed as usual in order to assess the position of the electrodes inside the cochlea. This radiography showed the electrode array to be in the superior semicircular canal in the right ear.Conclusion:Intra-operative monitoring tests during cochlear implant surgery play different roles; measurement of impedances and neural response imaging can evaluate the integrity of implant electrodes and the status of the electrode–cochlea interface, but it must not be the sole way in which correct positioning of the array is confirmed. In our opinion, intra-operative radiological assessment is mandatory during cochlear implant surgery.