bluuebunny/crossref_metadata_2025_split huggingface dataset:
Re-explorative Parathyroid Surgery for Persistent and Recurrent Primary Hyperparathyroidism
Authors: Afors Karolina , O'Connell Rachel L , Thomas Martin H 
Published: December 2011

ABSTRACT
Primary hyperparathyroidism (HPT) is treated by parathyroidectomy. Excision of abnormal parathyroid tissue is curative in the majority of cases. Postoperative persistent or recurrent HPT has been reported up to 30%. The purpose of this study was to evaluate the role of imaging techniques and determine the efficacy of reexplorative surgery. A total of 306 patients underwent parathyroidectomy between 2000 and 2009. Twelve patients (3.9%) were not cured. Two patients declined further treatment, the other 10 patients underwent further investigation and surgery. Imaging and results of redo surgery together with associated complications were evaluated. All 10 patients were investigated with sestamibi, which accurately localized aberrant parathyroid tissue in three cases and ultrasound scans which also localized three cases. CT was useful in one of the three cases for which it was used. PET and MRI were not helpful. Twelve glands were resected, six adenomas, five hyperplastic and one normal gland. Nine of the 10 reoperated patients became normocalcemic. Complications included a bilateral recurrent laryngeal paresis. In total, 317 operations were performed and 303 of 306 (99%) patients were cured. Redo surgery for HPT is challenging and carries higher risks than primary surgery. Sestamibi and ultrasound scans are the most helpful imaging modalities. When there is concordance a targeted approach may be considered, otherwise a more extensive dissection is required. Redo parathyroid surgery should be considered, even if scans are unhelpful, for patients who are symptomatic or young or have a persistently high calcium level.
Secondary Hyperparathyroidism Presenting with Vocal Cord Paralysis
Authors: Ho Thomas WT , McMullen Todd P 
Published: December 2011

ABSTRACT
The association of vocal cord paralysis with tumors in the neck generally raises the suspicion of an underlying malignancy. We report the clinical course, imaging and operative findings in a patient with secondary hyperparathyroidism presenting with vocal cord paralysis. The related literature is also reviewed. A 45-year-old man with end-stage renal failure was awaiting surgical treatment for secondary hyperparathyroidism. Ultrasound of the neck demonstrated hypoechoic nodules consistent with enlarged parathyroid glands. Several months later, just before the scheduled date for parathyroid surgery, he developed increasing hoarseness and vocal fatigue. Direct laryngoscopy revealed an immobile left vocal cord (VC). Neck examination and further imaging did not reveal the source of VC palsy. A presumptive diagnosis of thyroid or parathyroid malignancy involving the recurrent laryngeal nerve (RLN) was made. Intraoperatively, four enlarged parathyroid glands were encountered. The left superior gland was seen stretching and displacing the RLN without evidence of direct invasion. This was successfully dissected off while preserving the RLN. The remaining three parathyroid glands were subsequently removed with autotransplantation of a parathyroid remnant. In addition, a left thyroid lobectomy and ipsilateral level VI dissection was performed. Final pathology revealed parathyroid hyperplasia and thyroid follicular adenoma. No malignancy was seen. Three weeks later, the patient's biochemistry had normalized and his voice improved. Laryngoscopy confirmed a mobile left VC. Benign parathyroid tumors are rarely associated with RLN compression leading to VC paralysis. Such diagnoses are difficult to make preoperatively. In the absence of malignant invasion, the RLN should be preserved during surgery as it is likely to recover once the compression is relieved.
Adrenal Adenoma–Hemangioma: A Unique Collision Tumor
Authors: Raveendran Subhash , Babu SP Harish , Kumar ML Arun , Iyoob VA , Natesh Bonny 
Published: December 2011

ABSTRACT
Collision tumors are distinct and rare groups of neoplasms characterized by occurrence of two histologically different neoplasms at one site as a single lesion without significant tissue admixture. They are described in different parts of the body including adrenal glands. Collision tumors reported in relation to adrenal gland are mainly combinations of adenoma and metastasis. Here we present a case of incidentally detected adrenal collision tumor with adenoma and hemangioma as components which is a very rare and unique occurrence.
Overlap of Pseudohypoparathyroidism and Primary Hyperparathyroidism in a Patient: Just a Coincidence?
Authors: Neukirch Ana Karena , Heckmann Christian , Weyerbrock Norbert , Günther Silke , Dotzenrath Cornelia 
Published: December 2011

ABSTRACT
A 56-year-old female patient with the phenotype of Albright's hereditary osteodystrophy (AHO) and pseudohypoparathyroidism 1a (PHP) diagnosed in 1987 was shown to have a heterozygote inactivating mutation on the GNAS1 gene. The patient has been treated with oral calcium and vitamin D since diagnosis of PHP 1a and developed primary hyperparathyroidism (pHPT) in 2009. Ultrasound as well as 99Tcsestamibi could demonstrate a lesion in the right lower position. Intraoperatively, a solitary parathyroid adenoma was found and resected leading to a ‘normalization’ of PTH and calcium. This case highlight is the rare coincidence of PHP, AHO and pHPT.
Spin‐orbit interaction in a two‐dimensional electron gas: A SU(2) formulation
Authors: Raimondi R. , Schwab P. , Gorini C. , Vignale G. 
Published: December 2011

AbstractSpin‐orbit interaction is usefully classified as extrinsic or intrinsic, depending on its origin: the potential due to random impurities (extrinsic), or the crystalline potential associated with the band or device structure (intrinsic). In this paper we will show how, by using a SU(2) formulation, the two sources may be described in an elegant and unified way. As a result we obtain a simple description of the interplay of the two types of spin‐orbit interaction, and a physically transparent explanation of the vanishing of the d.c. spin Hall conductivity in a Rashba two‐dimensional electron gas when spin relaxation is neglected, as well as its reinstatement when spin relaxation is allowed. Furthermore, we obtain an explicit formula for the transverse spin polarization created by an electric current, which generalizes the standard formula obtained by Edelstein, and Aronov and Lyanda‐Geller by including extrinsic spin‐orbit interaction and spin relaxation.
Learning from “Coffee Rings”: Ordered Structures Enabled by Controlled Evaporative Self‐Assembly
Authors: Han Wei , Lin Zhiqun 
Published: December 2011

AbstractResearch into the evaporation of solutions is not only aimed at a better understanding the physics of evaporation, but increasingly at capitalizing on the extremely simple method it offers to assemble diverse nonvolatile solutes into complex ordered structures on the submicron and longer length scales. This Review highlights recent advances in evaporative assembly of confined solutions, focusing especially on recently developed approaches that provide structures with unprecedented regularity composed of polymers, nanoparticles, and biomaterials, by controlled evaporation‐driven, flow‐aided self‐assembly. A broad range of variables that can control the deposition are explored and the future directions of this rich field are presented.
Influence of Periodic Nitrogen Functionality on the Selective Oxidation of Alcohols
Authors: Chan‐Thaw Carine E. , Villa Alberto , Veith Gabriel M. , Kailasam Kamalakannan , Adamczyk Leslie A. , Unocic Raymond R. , Prati Laura , Thomas Arne 
Published: December 2011

AbstractAn enhancement in catalytic alcohol oxidation activity is attributed to the presence of nitrogen heteroatoms on the external surface of a support material. The same Pd particles (3.1–3.2 nm) were supported on polymeric carbon–nitrogen supports and used as catalysts to selectively oxidize benzyl alcohol. The polymeric carbon–nitrogen materials include covalent triazine frameworks (CTF) and carbon nitride (C3N4) materials with nitrogen content varying from 9 to 58 atomic percent. With comparable metal exposure, estimated by X‐ray photoelectron spectroscopy, the activity of these catalysts correlates with the concentration of nitrogen species on the surface. Because the catalysts showed comparable acidic/basic properties, this enhancement cannot be ascribed to the Lewis basicity but most probably to the nature of N‐containing groups that govern the adsorption sites of the Pd nanoparticles.
Intramolecular HAr Ligand Exchange between Silicon and Boron: Functionality Transfer of SiH to BH
Authors: Kawachi Atsushi , Morisaki Hiroshi , Nishioka Norimasa , Yamamoto Yohsuke 
Published: December 2011

Abstracto‐C6H4(SiR3−nHn)(BMes2) (1; R=Me, Ph; n=1, 2) undergo MesH (Mes=mesityl) ligand exchange between the silicon atom and the boron atom to form o‐C6H4(SiMesR3−nHn−1)(BMesH) (6) upon heating. The resulting hydroborane intermediates (6) immediately react with benzaldehyde to afford their corresponding benzyloxyboranes (5). A DFT study of model compounds reveals the transition states of the ligand exchange. A hydride abstraction from the silicon atom by the boron center is key to reaching the transition states, which include the tricoordinate silyl‐cation moiety and the tetracoordinate hydridoborate moiety.
Total Synthesis of (+)‐Asteriscanolide: Further Exploration of the Rhodium(I)‐Catalyzed [(5+2)+1] Reaction of Ene‐Vinylcyclopropanes and CO
Authors: Liang Yong , Jiang Xing , Fu Xu‐Fei , Ye Siyu , Wang Tao , Yuan Jie , Wang Yuanyuan , Yu Zhi‐Xiang 
Published: December 2011

AbstractThe total synthesis of (+)‐asteriscanolide is reported. The synthetic route features two key reactions: 1) the rhodium(I)‐catalyzed [(5+2)+1] cycloaddition of a chiral ene‐vinylcyclopropane (ene‐VCP) substrate to construct the [6.3.0] carbocyclic core with excellent asymmetric induction, and 2) an alkoxycarbonyl‐radical cyclization that builds the bridging butyrolactone ring with high efficiency. Other features of this synthetic route include the catalytic asymmetric alkynylation of an aldehyde to synthesize the chiral ene‐VCP substrate, a highly regioselective conversion of the [(5+2)+1] cycloadduct into its enol triflate, and the inversion of the inside–outside tricycle to the outside–outside structure by an ester‐reduction/elimination to enol‐ether/hydrogenation procedure. In addition, density functional theory (DFT) rationalization of the chiral induction of the [(5+2)+1] reaction and the diastereoselectivity of the radical annulation has been presented. Equally important is that we have also developed other routes to synthesize asteriscanolide using the rhodium(I)‐catalyzed [(5+2)+1] cycloaddition as the key step. Even though these routes failed to achieve the total synthesis, these experiments gave further useful information about the scope of the [(5+2)+1] reaction and paved the way for its future application in synthesis.
A stochastic model for survival of early prostate cancer with adjustments for leadtime, length bias, and over‐detection
Authors: Wu Grace Hui‐Min , Auvinen Anssi , Yen Amy Ming‐Fang , Hakama Matti , Walter Stephen D. , Chen Hsiu‐Hsi 
Published: December 2011

AbstractTo compare the survival between screen‐detected and clinically detected cancers, we applied a series of non‐homogeneous stochastic processes to deal with leadtime, length bias, and over‐detection by using full information on detection modes obtained from the Finnish randomized controlled trial for prostate cancer screening. The results show after 9‐year follow‐up the hazard ratio of prostate cancer death for screen‐detected cases against clinically detected cases increased from 0.24 (95% CI: 0.16–0.35) without correction for these biases, to 0.76 after correction for leadtime and length biases, and finally to 1.03 (95% CI: 0.79–1.33) for a further adjustment for over‐detection. Adjustment for leadtime and length bias but no over‐detection led to a 24% reduction in prostate cancer death as a result of prostate‐specific antigen test. The further calibration of over‐detection indicates no gain in survival of screen‐detected prostate cancers (excluding over‐detected case as stayer considered in the mover–stayer model) as compared with the control group in the absence of screening that is considered as the mover. However, whether the model assumption on over‐detection is robust should be validated with other data sets and longer follow‐up.
Terpenoids are Widespread in Actinomycetes: A Correlation of Secondary Metabolism and Genome Data
Authors: Citron Christian A. , Gleitzmann Julia , Laurenzano Gianfranco , Pukall Rüdiger , Dickschat Jeroen S. 
Published: December 2011

AbstractThe genomes of all bacteria with publicly available sequenced genomes have been screened for the presence of sesquiterpene cyclase homologues, resulting in the identification of 55 putative geosmin synthases, 23 homologues of 2‐methylisoborneol synthases, and 98 other sesquiterpene cyclase homologues. Most of these enzymes by far were found in actinomycetes. The terpenoid volatiles from 35 strains, including 31 actinomycetes and four strains from other taxa, were collected by using a closed‐loop stripping apparatus and identified by GC‐MS. All of these bacteria apart from one strain encode sesquiterpene cyclase homologues in their genomes. The identified volatile terpenoids were grouped according to structural similarities and their biosynthetic relationship, and the results of these analyses were correlated to the available genome information, resulting in valuable new insights into bacterial terpene biosynthesis.
Nanographite Impurities in Carbon Nanotubes: Their Influence on the Oxidation of Insulin, Nitric Oxide, and Extracellular Thiols
Authors: Chng Elaine Lay Khim , Pumera Martin 
Published: December 2011

AbstractThere has been growing interest in the use of modified‐carbon‐nanotube electrodes in applications such as the electrochemical detection of biologically significant compounds, owing to their apparent “electrocatalytic” properties and ability to enhance oxidative signals. In spite of their salient properties, little work has been done to further examine the reasons for these reported characteristics. In this report, we present clear evidence that the presence of nanographite impurities within carbon nanotubes (CNTs) is responsible for providing the previously reported enhanced electrochemical response. We have demonstrated this effect on homocysteine, N‐acetyl‐L‐cysteine, nitric oxide, and insulin, which are important biological agents in the body. Moreover, we also showed that the influence of nanographite impurities on the electrochemistry of carbon nanotubes is prevalent among a variety of CNTs, such as single‐walled CNTs, double‐walled CNTs, and few‐walled CNTs. Our findings will have a profound influence upon the biomedical applications of CNTs.
Discrimination and Classification of Ginsenosides and Ginsengs Using Bis‐Boronic Acid Receptors in Dynamic Multicomponent Indicator Displacement Sensor Arrays
Authors: Zhang Xiaojun , You Lei , Anslyn Eric V. , Qian Xuhong 
Published: December 2011

AbstractGinsenosides are complex natural products with a diverse array of biological activities, but their molecular recognition and sensing is challenging. A library of simple bis‐boronic acid‐based receptors with various spacers was synthesized for the sensing of ginsenosides. The incorporation of two boronic acids allowed the pairing of two indicators, which can simultaneously bind the receptors or two saccharides within the ginsenosides. A cross‐reactive sensing array was therefore constructed using the receptors in conjunction with different pairs of indicators. LDA plots created from the colorimetric response of the hosts and indicator pairs reveal excellent classification of the ginsenosides, and the corresponding loading plots reveal the cross‐reactivity of the receptors. In addition, several commercial ginseng extracts were unambiguously classified using the same sensing array. The assay reported here should be applicable to the analysis of other large saccharide‐based natural products.
Synthesis and Antimicrobial Activity of New 2,5‐Disubstituted 1,3,4‐Oxadiazoles and 1,2,4‐Triazoles and Their Sugar Derivatives
Authors: El‐Sayed Wael A. , Ali Omar M. , Hendy Hend A. , Abdel‐Rahman Adel A.‐H. 
Published: December 2011

AbstractA series of new 2,5‐disubstituted‐1,3,4‐oxadiazole and 1,2,4‐triazole derivatives were synthesized by heterocyclization of acid hydrazide 1 and thiosemicarbazide derivative 2. Furthermore, the acyclic C‐nucleoside analogs were prepared by cyclization of their corresponding sugar hydrazones by reaction with acetic anhydride. The antimicrobial activity of the prepared compounds was evaluated and some of the synthesized compounds revealed good activities against fungi.
Synthesis and Characterization of a Novel Soluble Diethoxy Phosphoryl Chitosan
Authors: Ma Li , Li Kerang , Li Limin , Liu Pu 
Published: December 2011

AbstractA simple and efficient method for the preparation of a novel soluble chitosan derivative, diethoxy phosphoryl chitosan (PH‐chitosan), has been developed. Ph‐chitosan was characterized by elemental analysis, FT‐IR, NMR, ICP, XRD, TG and SEM, respectively. The chemical identity of PH‐chitosan was determined by FT‐IR and confirmed by NMR, and those results unequivocally demonstrated that diethoxy phosphoryl groups were grafted onto the amino and hydroxyl groups of chitosan. The results of XRD indicated that the crystalline structure of chitosan was destroyed due to the incorporation of diethoxy phosphoryl group resulting in loss of hydrogen bond. The analysis of TG demonstrated that PH‐chitosan was less thermal stable than chitosan. This simple synthetic method provided a new and available approach to prepare a soluble high molecule weight chitosan derivative.
Direct α‐Alkylation of Aldehydes by Brønsted‐Acid Catalysis
Authors: Zhu Xiangrong , Wang Ting , Guo Qixiang 
Published: December 2011

AbstractA Brønsted acid catalyzed direct alkylation reaction of aldehydes was described. The 3,5‐dinitrobenzoic acid promoted the reaction between aldehydes and diarylmethanols to afford the corresponding alkylation products with middle to high yields (up to 91% yield).
Synthesis of 2,2‐Bis‐C‐functionalized Chain Glucosid‐3‐ketals
Authors: Zhang Fuyi , Liu Hong , Sheng Yingming , Liu Hongmin 
Published: December 2011

AbstractNovel 2,2‐bis‐C‐functionalized chain glucosid‐3‐uloses have been synthesized in the form of ketal. The synthesis is rather convenient through one pot multistep reactions and no expensive reagents are involved. The products are formed via autoxidation‐Michael addition mechanism and their structures were characterized by X‐ray crystallographic analysis. Their crystal stuctures are stablilized by intermolecular hydrogen bonds and double‐strand supramolecular stacking is observed.
Fantastic Plastic
Authors: Banerji Amitabh , Tausch Michael W. , Scherf Ullrich 
Published: December 2011

AbstractMit diesem Beitrag werden fachliche Grundlagen, experimentelle Zugänge und didaktische Materialien für die curriculare Innovation von Chemieunterricht vorgestellt. Die Experimente und Materialien beziehen sich auf das Phänomen der Elektrolumineszenz, das im Zusammenhang mit modernen Flachbildschirmen ein alltagsnaher, motivierender Kontext für Schülerinnen und Schüler ist. Gleichzeitig handelt es sich im Zusammenhang mit der Forderung nach energiesparenden, in Farbe, Leuchtkraft und Pixelgröße maßgeschneiderten Lichtquellen um ein aktuelles Forschungs‐ und Entwicklungsfeld in Wissenschaft und Technik.
Hydrogenolysis of Glycerol to 1,2‐Propanediol over Ru–Cu Bimetals Supported on Different Supports
Authors: Liu Huizhen , Liang Shuguang , Jiang Tao , Han Buxing , Zhou Yinxi 
Published: December 2011

AbstractGlycerol is a low‐cost and renewable resource, and its utilization is of great interest for chemical industry and sustainable development. In this work, a series of Ru–Cu bimetallic catalysts were prepared using different supports in an attempt to develop highly efficient catalysts. Hydrogenolysis of aqueous solution of glycerol was performed with the supported Ru–Cu catalysts. The bimetallic catalysts were very efficient for catalyzing the hydrogenolysis of glycerol compared with the corresponding monometallic catalysts. One hundred percent of glycerol conversion and 78.5% of 1,2‐propanediol yield could be achieved at 180°C and 8 MPa.
Experimental and Computational Active Site Mapping as a Starting Point to Fragment‐Based Lead Discovery
Authors: Behnen Jürgen , Köster Helene , Neudert Gerd , Craan Tobias , Heine Andreas , Klebe Gerhard 
Published: December 2011

AbstractSmall highly soluble probe molecules such as aniline, urea, N‐methylurea, 2‐bromoacetate, 1,2‐propanediol, nitrous oxide, benzamidine, and phenol were soaked into crystals of various proteins to map their binding pockets and to detect hot spots of binding with respect to hydrophobic and hydrophilic properties. The selected probe molecules were first tested at the zinc protease thermolysin. They were then applied to a wider range of proteins such as protein kinase A, D‐xylose isomerase, 4‐diphosphocytidyl‐2C‐methyl‐D‐erythritol synthase, endothiapepsin, and secreted aspartic protease 2. The crystal structures obtained clearly show that the probe molecules populate the protein binding pockets in an ordered fashion. The thus characterized, experimentally observed hot spots of binding were subjected to computational active site mapping using HotspotsX. This approach uses knowledge‐based pair potentials to detect favorable binding positions for various atom types. Good agreement between the in silico hot spot predictions and the experimentally observed positions of the polar hydrogen bond forming functional groups and hydrophobic portions was obtained. Finally, we compared the observed poses of the small‐molecule probes with those of much larger structurally related ligands. They coincide remarkably well with the larger ligands, considering their spatial orientation and the experienced interaction patterns. This observation confirms the fundamental hypothesis of fragment‐based lead discovery: that binding poses, even of very small molecular probes, do not significantly deviate or move once a ligand is grown further into the binding site. This underscores the fact that these probes populate given hot spots and can be regarded as relevant seeds for further design.
Engineering and Functionalization of the Disulfide‐Constrained Miniprotein Min‐23 as a Scaffold for Diagnostic Application
Authors: Zoller Frederic , Schwaebel Thimon , Markert Annette , Haberkorn Uwe , Mier Walter 
Published: December 2011

AbstractMiniproteins are scaffolds for the development of alternative non‐immunoglobin binding agents for medical applications. This peptide format features high tolerance to sequence mutagenesis, excellent proteolytic stability, and fast blood pool clearance. Herein we present the total chemical synthesis of the disulfide‐constrained scaffold Min‐23 and its functionalization for in vitro and in vivo application. Optimized solid‐phase peptide chemistry and oxidative folding strategies were developed to engineer this miniprotein with native‐like disulfide configuration. High levels of serum stability and proteolytic resistance, as well as a beneficial pharmacokinetic profile for diagnostic imaging, were determined by using radiolabeling techniques such as positron emission tomography. The reported achievements highlight Min‐23 as a promising scaffold for the development of novel recognition molecules for medical application.