bluuebunny/crossref_metadata_2025 huggingface dataset:
Continuous Separation of Racemic 3,5‐Dinitrobenzoyl‐Amino Acids in a Centrifugal Contact Separator with the Aid of Cinchona‐Based Chiral Host Compounds
Authors: Hallett Andrew J. , Kwant Gerard J. , de Vries Johannes G.
Published: January 2009

Resolution through revolution: It is possible to extract 3,5‐dinitrobenzoyl‐protected amino acids enantioselectively with the aid of a table‐top centrifugal contact separator and a catalytic amount of a chiral host compound based on the Cinchona alkaloids. Enantioselectivities of up to 80 % could be reached in a single pass. This allows the development of a process for the continuous separation of racemates.

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The resolution of racemates is mostly performed by crystallisation of diastereomeric salts. Direct physical separation could be much more efficient, but so far most concepts, with the exception of SMB, have proven to be non‐scaleable. Here we report the first scalable process for the resolution of N‐protected amino acid derivatives through selective extraction, with the aid of a catalytic amount of a chiral host compound based on Cinchona alkaloids. The method hinges on the use of centrifugal contact separators (CCSs) for fast mixing and separation. Although the highest ee obtained was only 80 %, the concept can be extended through the use of a series of CCSs in countercurrent mode to effect full separation.
The Interplay between Steric and Electronic Effects in SN2 Reactions
Authors: Fernández Israel , Frenking Gernot , Uggerud Einar
Published: January 2009

Myths of steric hindrance: In contrast with current opinion, energy decomposition analysis shows that the presence of bulky substituents at carbon leads to the release of steric repulsion in the transition state shown in the graphic. It is rather the weakening of the electrostatic attraction, and in particular the loss of attractive orbital interactions, that are responsible for the activation barrier.

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Quantum chemical calculations for SN2 reactions of H3EX/X− systems, in which E=C or Si and X=F or Cl, are reported. In the case of the carbon system we also report on bulkier species in which the hydrogen atoms are substituted by methyl groups. It is shown how the variation in the individual energy terms of the Morokuma/Ziegler energy decomposition analysis (EDA) scheme along the reaction coordinate from reactants to products provides valuable insight into the essential changes that occur in the bond‐breaking/bond‐forming process during SN2 reactions. The EDA results for the prototypical SN2 reaction of the systems [X⋅⋅⋅R3E⋅⋅⋅X]−, in which the interacting fragments are [X⋅⋅⋅X]2− and [R3E]+, have given rise to a new interpretation of the factors governing the reaction course. The EDA results for the carbon system (E=C) show that there is less steric repulsion and stronger electrostatic attraction in the transition structure than in the precursor complex and that the energy increase comes mainly from weaker orbital interactions. The larger barriers for systems in which R3 is bulkier also do not arise from increased steric repulsion, which is actually released in the transition structure. It is rather the weakening of the electrostatic attraction, and in particular the loss of attractive orbital interactions, that are responsible for the activation barrier. The D3h energy minima of the silicon homologues [XH3SiX]− is driven by the large increase in the electrostatic attractions and also of stronger orbital interactions, while the steric interactions is destabilizing.
Reviewing the Polyolefin Cyclization Reaction of the C35 Polyprene Catalyzed by Squalene‐Hopene Cyclase
Authors: Hoshino Tsutomu , Kumai Yuko , Sato Tsutomu
Published: January 2009

A review of the polycyclization reaction of the C35 polyprenoid by squalene‐hopene cyclase: Surprisingly, our results completely disagree with a previous publication in which it was reported that a hexacyclic skeleton was constructed as the single product. In our work many tri‐ and tetracyclic scaffolds were isolated, but no penta‐ or hexacycles. The reasons for the different results and the mechanism of the polycyclization reaction are discussed (see figure).

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Squalene‐hopene cyclase (SHC) catalyzes the polycyclization of squalene (C30) to the pentacyclic hopene with regio‐ and stereochemical specificity. In this study, we reviewed the polycyclization reaction of the C35 polyprenoid catalyzed by SHC. Surprisingly, our results completely disagreed with a previous publication in which it was reported that a hexacyclic skeleton was constructed as the single product in 10 % yield (I. Abe, H. Tanaka, H. Noguchi, J. Am. Chem. Soc. 2002, 124, 14514–14515). Our experimental results showed that many tri‐ and tetracyclic products, up to 12, including novel carbocyclic cores, were generated in a high conversion ratio (97 %), but no detectable amounts of the penta‐ and hexacycle were produced. The mechanisms for the formation of the C35 polyprene products isolated by us are discussed in this paper. The following four conformations were generated during the polycyclization cascade: chair‐chair‐boat, chair‐chair‐chair, chair‐chair‐chair‐boat, and chair‐chair‐chair‐chair. Larger amounts of the false intermediates with 13α‐H (tricycle) and 17α‐H (tetracycle) were produced compared with the true intermediates (13β‐H and 17β‐H), which indicates that the C35 polyprene cannot fold correctly in the enzyme cavity due to the extra C5 unit appended to squalene. This would have promoted the formation of the aborted cyclization products with tri‐ and tetracycles. In addition, the fact that no penta‐ or hexacyclic products were formed further indicates that SHC does not have sufficient space to accommodate the entire carbon framework of C35.
Diaminoterephthalates: Scaffolds for Combinatorial Chemistry
Authors: Pflantz Rebekka , Christoffers Jens
Published: January 2009

Fluorescent building blocks: Tetracarboxyamides with a central fluorescent diaminoterephthalate unit were prepared from succinyl succinates following a combinatorial‐like strategy. The 2,5‐diaminoterephthalates (see scheme; PG=protecting group) possess four points of diversification and are introduced as new scaffolds for combinatorial chemistry.

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2,5‐Diaminoterephthalates that possess four points of diversification are introduced as new scaffolds for combinatorial chemistry. A straightforward synthesis of an orthogonally protected platform compound was developed. This platform was transformed by stepwise deprotection and amidation of the two amino and two carboxylic acid moieties into tetra‐amides with a central aromatic ring as a fluorescence chromophore.
Structure and Electronic Configuration of an Iron(II) Complex in a LIESST State: A Pump and Probe Method
Authors: Sheu Chou‐Fu , Chen Kowa , Chen Szu‐Miao , Wen Yuh‐Sheng , Lee Gene‐Hsiang , Chen Jin‐Ming , Lee Jyh‐Fu , Cheng Bing‐Ming , Sheu Hwo‐Shuenn , Yasuda Nobuhiro , Ozawa Yoshiki , Toriumi Koshiro , Wang Yu
Published: January 2009

Switchable molecules: The electronic configurations of the Fe center in trans‐[Fe(tzpy)2(NCS)2] in low‐spin, high‐spin, and LIESST states (LIESST=light‐induced excited spin‐state trapping) were confirmed by K‐ and L‐edge X‐ray absorption and magnetic measurements. The molecular structures at 40 K before and after irradiation are superimposed in the picture, which demonstrates a single‐crystal‐to‐single‐crystal transition by irradiation.

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Two polymorphs of mononuclear six‐coordinate iron(II) spin‐crossover complex trans‐[Fe(tzpy)2(NCS)2] (tzpy=3‐(2‐pyridyl)[1,2,3]triazolo[1,5‐a]pyridine) (1) were isolated and structurally characterized. According to the thermally dependent magnetic measurements, polymorph A undergoes a gradual spin transition from a paramagnetic high‐spin state (5T2, S=2, HS‐1) above 200 K to a diamagnetic low‐spin state (1 A1, S=0, LS‐1) below 120 K, whereas polymorph B shows an abrupt spin transition with T1/2 at 102 K. Molecular and crystal structures of polymorph A in the HS‐1 and LS‐1 states were studied at 300 and 40 K, respectively. Significant differences in FeN distances and coordination geometries of Fe were found between the two spin states, as expected. Light‐induced excited spin state trapping (LIESST) was observed upon irradiating the crystal with 532 nm laser light at 40 K, whereupon a metastable high‐spin state (HS‐2) was formed; the molecular and crystal structure of this metastable state were investigated by a pump and probe method because of its relatively fast relaxation. The electronic configuration of the Fe center in the HS‐1, LS‐1, and LIESST (HS‐2) states were further confirmed by Fe K‐ and L‐edge absorption spectroscopy. In addition, the CN stretching frequency on the ligand can also be followed through the spin transition. The excitation and relaxation process concerning such metastable state were followed by the CN stretching frequency and magnetic susceptibility measurements in the temperature ranges 15–55 K and 5–80 K, respectively. The structure and electronic configuration of the LIESST state of polymorph A were firmly established by X‐ray diffraction, X‐ray absorption, infrared absorption, and magnetic measurements. A single‐crystal‐to‐single‐crystal transition through irradiation was demonstrated. The changes in structure and electronic configuration as a result of the spin transition are believed to occur concurrently.
Synthesis of Tricyclic Fused 3‐Aminopyridines through Intramolecular CoI‐Catalyzed [2+2+2] Cycloaddition between Ynamides, Nitriles, and Alkynes
Authors: Garcia Pierre , Moulin Solenne , Miclo Yves , Leboeuf David , Gandon Vincent , Aubert Corinne , Malacria Max
Published: January 2009

Three‐ring circus: An expedient route to tricyclic fused 2‐trimethylsilyl‐3‐aminopyridines exhibiting unprecedented skeletons is described. The key step is a very efficient cobalt‐catalyzed [2+2+2] cycloaddition of a polyunsaturated compound displaying an ynamide, an alkyne, and a nitrile functionality (see picture).

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The first [2+2+2] cocyclizations between ynamides, nitriles, and alkynes are reported. They open a new access to unprecedented nitrogen‐containing heterocycles of type 2‐trimethylsilyl‐3‐aminopyridines. Such frameworks, which can be found in various compounds of biological interest, are very difficult to prepare by conventional methods. However, using [CpCo(C2H4)2] (Cp=cyclopentadienyl) as catalyst, the intramolecular cyclizations could be achieved in up to 100 % yield. The presence of the trimethylsilyl group allowed a rare type of Hiyama cross‐coupling: one of the silylated pyridines could be coupled with p‐iodoanisole to give a new type of biaryl system.
ChemInform Abstract: Structure Effect of TsDPEN Derivatives on Enantioselectivity of Asymmetric Transfer Hydrogenation.
Authors: Liu Juntao , Wu Yinuo , Li Xingshu , Chan Albert S. C.
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ionic Polymer‐Supported Copper(I): A Reusable Catalyst for Huisgen′s 1,3‐Dipolar Cycloaddition.
Authors: Sirion Uthaiwan , Bae Yu Jin , Lee Byoung Se , Chi Dae Yoon
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of Novel Bis‐1,3,4‐thiadiazoles, Bis‐1,2,4‐triazoles and Their Antimicrobial Activity.
Authors: Burghate Megha K. , Burghate S. K. , Berad B. N.
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A Highly Efficient Catalyst‐Free Cycloisomerization Approach to Indolizinones.
Authors: Kim Ikyon , Choi Jihyun , Lee Sunkyung , Lee Ge Hyeong
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Magnetism in Graphene Systems
Authors: Kan Erjun , Li Zhenyu , Yang Jinlong
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Solid‐State Ionic Devices
Authors: Wachsman Eric D. , Traversa Enrico
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Supramolecular Coordination Chemistry: The Synergistic Effect of Serendipity and Rational Design
Authors: Saalfrank Rolf W. , Maid Harald , Scheurer Andreas
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Bidentate Ligands Containing a Heteroatom—Phosphorus Bond
Authors: Kok Stanton H. L. , Au‐Yeung Terry T.‐L. , Cheung Hong Yee , Lam Wing Sze , Chan Shu Sun , Chan Albert S. C.
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Metal—Organic Frameworks for Asymmetric Catalysis and Chiral Separations
Authors: Lin Wenbin
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Bile Acid Scaffolds in Supramolecular Chemistry: The Interplay of Design and Synthesis
Authors: Davis Anthony P.
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Thermodynamically Controlled Deracemization Utilizing Inclusion Complexation
Authors: Kaku Hiroto
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Sesquiterpene Lactones and Their Precursors as Chemosystematic Markers in the Tribe Cichorieae of the Asteraceae
Authors: Zidorn Christian
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Large‐Scale Recordings for Drug Screening in Neural Circuit Systems
Authors: Ikegaya Yuji
Published: January 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Angiographic and Clinical Implications of Combined ST‐segment Elevation in Anterior and Inferior Leads in Acute Myocardial Infarction
Authors: Jim Man‐Hong , Chan Annie On‐On , Tang Man‐Oi , Siu Chung‐Wah , Lee Stephen Wai‐Luen , Lau Chu‐Pak
Published: January 2009

Background

The clinical and angiographic findings of patients suffered from acute myocardial infarction (MI) and presented with combined ST elevation in both anterior and inferior leads remain unclear.

Hypothesis

These patients might have ≥ 1 coronary arteries occluded.

Methods

From January 2002 to December 2006, 49 consecutive patients were found to have ST elevation in both anterior and inferior leads during myocardial infarction. Patients who had left circumflex artery occlusion (acute or chronic) were excluded. These patients were divided into 4 types according to the infarct‐related artery (IRA) and status of the contralateral vessel patency: left anterior descending artery (LAD) as the IRA with a patent right coronary artery (RCA) (type 1A, n = 25); LAD as IRA with an occluded RCA (type 1B, n = 1); RCA as IRA with a patent LAD (type 2A, n = 19); and RCA as IRA with an occluded LAD (type 2B, n = 4).

Results

Single vessel occlusion (type A angiographic pattern) was found in 90% of patients. Type 1A patients had a larger infarct size than that of 2A. ST elevation in V2 ≥ V3 identified RCA as the IRA with a high specificity (92%) and sensitivity (74%). Type 2B patients (2‐vessel occlusion) had a larger infarct size than that of 2A; however, no electrocardiogram (ECG) criteria could reliably differentiate them.

Conclusion

In a real world situation, single vessel occlusion is found in the majority of cases of combined ST elevation in anterior and inferior leads. ST elevation in V2 ≥ V3 distinguishes RCA against LAD as the IRA with high accuracy. Copyright © 2009 Wiley Periodicals, Inc.
Target‐organ protection with combination renin‐angiotensin‐system blockade
Authors: PrisantMD L. Michael
Published: January 2009

Pharmacologic blockade of the renin‐angiotensin‐aldosterone system (RAS) has antihypertensive, anti‐atherogenic, antioxidant, and anti‐inflammatory effects. Treatment with angiotensin‐converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) has been demonstrated to prevent atrial fibrillation and new‐onset diabetes, and provide cardiac, cerebral, and renal protection. Combination therapy with ACEIs and ARBs, compared with monotherapy, provides enhanced reno‐ and cardioprotection, although available data indicate that combination RAS blockade may be beneficial only in select patient groups, such as those with diabetes mellitus, chronic kidney disease, or heart failure (HF). In certain high‐risk patients, the use of ARBs provides comparable efficacy to that observed with ACEIs. The efficacy of these agents may stem from pleiotropic effects beyond blood pressure (BP) reduction. Several studies demonstrate achievement of clinical endpoints without significant effects on BP. Copyright © 2009 Wiley Periodicals, Inc.
Utility of implantable loop recorders for diagnosing unexplained syncope in clinical practice
Authors: Entem Felipe R. , Enriquez Susana G. , Cobo Manuel , Expósito Víctor , Llano Miguel , Ruiz Marta , Jose Olalla Juan , Otero‐Fernandez Macarena
Published: January 2009

Background

Establishing a symptom–rhythm correlation in patients with unexplained syncope is complicated because of its sporadic, infrequent, and unpredictable nature. Prolonged monitoring with an implantable loop recorder (ILR) allows the recording of electrocardiogram (ECG) data from a spontaneous syncopal event.

Hypothesis

The aim of this study was to evaluate the usefulness of the ILR for the diagnosis of syncope of unknown origin after conventional management in clinical practice.

Methods

We reviewed the results with ILR implantation in patients with syncope of unknown origin after conventional management in the cardiology department at HU Marques de Valdecilla (Santander, Cantabria, Spain).

Results

One hundred and forty patients (age 64 ± 16 y; 86 male [62%]) with syncope of unknown etiology after conventional work‐up underwent prolonged monitoring with an ILR from September 1998 to February 2006; 46 patients (33%) had structural heart disease. During a mean follow‐up of 346 ± 160 d, 51 patients (36.5%) had recurrent syncope with diagnostic ECG recording. An arrhythmic cause for syncope was found in 33 of them (64.5%), with bradycardia present in 27 (53%) and tachycardia in 6 (11%). There were no sudden deaths, and 1 patient suffered a complication related to a recurrence of syncope.

Conclusion

Long‐time experience with the ILR confirmed the utility of this device in the diagnosis of unexplained syncope in clinical practice. Most of these patients had syncope of arrhythmogenic etiology that could be successfully treated. This strategy of prolonged monitoring is safe even in patients with structural heart disease. Copyright © 2009 Wiley Periodicals, Inc.
Current trends in heart failure readmission rates: analysis of medicare data
Authors: Aranda Juan M. , Johnson James W. , Conti Jamie B.
Published: January 2009

Background

Despite advances in optimal pharmacologic therapy, patients with heart failure (HF) continue to have significant rehospitalization rates.

Hypothesis

We sought to provide current estimates on rates of readmission for Medicare patients with HF, and identify factors associated with an increased chance of readmission.

Methods

We used Medicare data from the 5% sample Standard Analytical File Limited Data Set for the years 2002 through 2004 to calculate readmission rates for HF. Clinical factors associated with readmission rates were identified using multivariate logistic regression.

Results

We identified 28,919 patients accounting for 38,849 HF hospitalizations in the 5% sample for 2003. These numbers project to an estimated 578,380 patients with 776,980 HF hospitalizations. In‐hospital mortality was 4.4% with an average length of stay of 5.5 ± 5.4 d. In the 6—9 mo following the initial HF admission, 60% of patients had 1 or more readmissions for any cause. Heart failure accounted for 28% of all readmissions. Factors associated with readmission for HF after the initial HF hospitalization included age < 65 y, geographic location, previous hospitalization, length of stay of initial HF hospitalization > 7 d, not receiving a cardiac device implant at the time of initial HF hospitalization, and history of comorbidities including diabetes, myocardial infarction, peripheral vascular disease, and stroke.

Conclusions

Medicare patients with HF continue to have significant morbidity and one of the highest in‐hospital mortality rates of any HF patient population. Factors associated with worse outcomes after an initial HF hospitalization can be used to identify patients who require aggressive therapy and follow‐up. Copyright © 2009 Wiley Periodicals, Inc.
Does Family History Have any Relevance to Clinical Practice in Cardiology?
Authors: Conti C. Richard
Published: January 2009

Years ago it was common to include all aspects of the history in the presentation, including the family history. In more recent times when there are multiple admissions of patients with cardiac symptoms (e.g., chest pain), the details of the present illness and any past cardiovascular illnesses are generally presented in detail, but there is a tendency to pay little attention to the family history and it is often neglected. Copyright © 2009 Wiley Periodicals, Inc.
Whole‐body section fluorescence imaging – a novel method for tissue distribution studies of fluorescent substances
Authors: Moestue Siver , Nunez Paula , Healey Andrew , Bjerke Roger , Indrevoll Bård , Skotland Tore , Hustvedt Svein Olaf
Published: January 2009

The present study demonstrates the usefulness of whole body section fluorescence imaging, a novel technique used in optical imaging drug discovery. This method is in principle an analog of whole body autoradiography, except that fluorescence is measured instead of radioactivity. The method was shown to have a linear concentration–response relationship over a 1000‐fold concentration range. Densitometric image analysis allowed semiquantitative studies of drug disposition and selective tumor retention of an optical imaging drug candidate. Copyright © 2009 John Wiley & Sons, Ltd.
Extent of lymphadenectomy and outcome for patients with stage I nonsmall cell lung cancer
Authors: Varlotto John M. , Recht Abram , Nikolov Margaret , Flickinger John C. , DeCamp Malcolm M.
Published: January 2009

BACKGROUND:

It is uncertain whether lymphadenectomy (LA) affects overall survival (OS) or disease‐free survival (DFS) rates for patients with stage I nonsmall cell lung cancer (NSCLC), as is the optimal number of lymph nodes that should be recovered.

METHODS:

There were 24,273 patients with stage I NSCLC diagnosed from 1992 to 2002 who were included in the Surveillance, Epidemiology, and End Results database and who underwent a definitive surgical procedure. Median follow‐up was 35 months.

RESULTS:

For the entire population, having LA was associated with an increase in the 5‐year OS rate from 41.6% to 58.4% (P<.0001) and in DFS from 58.0% to 73.09%, compared with not having LA. Outcome improved with increasing number of recovered lymph nodes, with a plateau at 11 or more lymph nodes. For patients diagnosed from 1998 to 2002 undergoing only N1 or only N2 dissections, LA was also associated with statistically significant improvements in OS in both groups and a significant difference and trend for improved DFS in the 2 groups, respectively. The maximum differences in both OS and DFS between those with no LA and those with LA occurred when 11 to 16 lymph nodes were removed for the former group or 7 to 10 lymph nodes for the latter group, respectively.

CONCLUSIONS:

LA was associated with increased rates of OS and DFS, compared with no LA. Our results also suggest the minimum number of recovered lymph nodes needed to see the maximum staging accuracy conferred by LA. Cancer 2009. © 2009 American Cancer Society.
Autoantibodies in autoimmune polyglandular syndrome type I patients react with major brain neurotransmitter systems
Authors: Fetissov Sergueï O. , Bensing Sophie , Mulder Jan , Le Maitre Erwan , Hulting Anna‐Lena , Harkany Tibor , Ekwall Olov , Sköldberg Filip , Husebye Eystein S. , Perheentupa Jaakko , Rorsman Fredrik , Kämpe Olle , Hökfelt Tomas
Published: January 2009

Patients with autoimmune polyglandular syndrome type I (APS1) often display high titers of autoantibodies (autoAbs) directed against aromatic L‐amino acid decarboxylase (AADC), tyrosine hydroxylase (TH), tryptophan hydroxylase (TPH), and glutamic acid decarboxylase (GAD). Neurological symptoms, including stiff‐man syndrome and cerebellar ataxia, can occur in subjects with high levels of GAD autoAbs, particularly when patient sera can immunohistochemically stain γ‐aminobutyric acid (GABA) neurons. However, it was not known if APS1 sera can also stain major monoamine systems in the brain. Therefore, in this work we applied sera from 17 APS1 patients known to contain autoAbs against AADC, TH, TPH, and/or GAD to rat brain sections and processed the sections according to the sensitive immunohistochemical tyramide signal amplification method. We found that autoAbs in sera from 11 patients were able to stain AADC‐containing dopaminergic, serotonergic, and noradrenergic as well as AADC only (D‐group) neurons and fibers in the rat brain, in several cases with a remarkably high quality and sensitivity (dilution up to 1:1,000,000); and, since they are human antibodies, they offer a good opportunity for performing multiple‐labeling experiments using antibodies from other species. Six APS1 sera also stained GABAergic neuronal circuitries. Similar results were obtained in the mouse and primate brain. Our data demonstrate that many APS1 sera can immunostain the major monoamine and GABA systems in the brain. Only in a few cases, however, there was evidence that these autoAbs can be associated with neurological manifestations in APS1 patients, as, e.g., shown in stiff‐man syndrome. J. Comp. Neurol. 513:1–20, 2009. © 2009 Wiley‐Liss, Inc.
Sharp regularity results on second derivatives of solutions to the Monge‐Ampère equation with VMO type data
Authors: Huang Qingbo
Published: January 2009

We establish interior estimates for Lp‐norms, Orlicz norms, and mean oscillation of second derivatives of solutions to the Monge‐Ampère equation det D2u = f(x) with zero boundary value, where f(x) is strictly positive, bounded, and satisfies a VMO‐type condition. These estimates develop the regularity theory of the Monge‐Ampère equation in VMO‐type spaces. Our Orlicz estimates also sharpen Caffarelli's celebrated W2, p‐estimates. © 2008 Wiley Periodicals, Inc.
Fluorescence Single‐Molecule Study of Cobra Phospholipase A2 Action on a Supported Gel‐Phase Lipid Bilayer
Authors: Chiu Chang‐Ru , Huang Wei‐Ning , Wu Wen‐Guey , Yang Tzyy‐Schiuan
Published: January 2009

Enzyme in action: The accumulated single‐molecule image (see picture) of phospholipase A2 (PLA2) 15–21 min after its injection on a lipid membrane shows transient interactions of PLA2 (blue) with the membrane surface and stable binding to the boundaries of membrane structure defects. The adsorbed PLA2 molecules move with a speed below the experimental resolution of 40 nm min−1.

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Previous nanoscale investigations of the gel‐state membrane surface structure under the action of phospholipase A2 (PLA2) suggest that single enzymes at work scoot on the membrane surface from the observed defects, which creates nanosized channels oriented along the lipid crystal‐packing structure. To date, however, there have been no reports of direct observation of PLA2 at the single‐molecule level focusing on how the enzymes interact with the defects. Herein, we report a single‐molecule fluorescence microscopy study on the action of enzymatically active rhodamine B‐labeled cobra PLA2 on a supported lipid membrane with visible packing defects on a glass substrate. Working with a gel‐state phospholipid bilayer, the low‐activity period (lag phase) of PLA2 action is followed by the burst binding of PLA2 molecules from aqueous solution on a few newly created active sites. These active sites are distinguished by a spatial resolution of ≈40 nm, which is below the diffraction limit. The rate of active‐site propagation as reflected by new PLA2 binding on the membrane surface is estimated to be ≈5 nm min−1. This rate is about two orders of magnitude slower than the propagation rate of hydrolyzed channels estimated by AFM studies on bee venom PLA2 on a similar membrane surface. This direct observation of PLA2 molecules allows the visualization of different PLA2 binding modes on the membrane surface and on the membrane boundary.
Influence of Mg Doping on GaN Nanowires
Authors: Zhang Dongdong , Xue Chengshan , Zhuang Huizhao , Sun Haibo , Cao Yuping , Huang Yinglong , Wang Zouping , Wang Ying
Published: January 2009

Magnesium‐doped GaN nanowires with different dopant concentrations are synthesized and their morphology, structure, growth properties, crystallinity, and optical properties investigated. The nanowires are single‐crystalline with hexagonal wurzite structure, and doping with 5 atom % of Mg gives nanowires with the best morphology and crystallinity (see HRTEM image).

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Magnesium‐doped GaN nanowires with different dopant concentrations are synthesized by ammoniating Ga2O3 thin films doped with Mg at 900 °C. Scanning electron microscopy (SEM), X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDX), high‐resolution transmission electron microscopy (HRTEM), and room‐temperature photoluminescence (PL) are employed to characterize the influences on the morphology, structure, crystallinity, and optical properties of Mg‐doped GaN nanowires. The results demonstrate that the nanowires are single‐crystalline with hexagonal wurzite structure. GaN nanowires doped with 5 atom % of Mg have the best morphology and crystallinity with a single‐crystalline structure, and at this composition the PL spectrum with the strongest UV peak is observed. The growth mechanism of crystalline GaN nanowires is discussed briefly.
Chiral Gold Nanoparticles
Authors: Gautier Cyrille , Bürgi Thomas
Published: January 2009

Nanoparticle chiralityhas attracted much attention recently, and the application of chiral nanoparticles to chiral technologies (see figure) is also of interest. This Minireview deals with advances in the preparation and characterization of chiral gold nanoparticles. Origins of the chiroptical properties and potential applications are discussed.

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Monolayer‐protected gold nanoparticles have many appealing physical and chemical properties such as quantum size effects, surface plasmon resonance, and catalytic activity. These hybrid organic–inorganic nanomaterials have promising potential applications as building blocks for nanotechnology, as catalysts, and as sensors. Recently, the chirality of these materials has attracted attention, and application to chiral technologies is an interesting perspective. This minireview deals with the preparation of chiral gold nanoparticles and their chiroptical properties. On the basis of the latter, together with predictions from quantum chemical calculations, we discuss different models that were put forward in the past to rationalize the observed optical activity in metal‐based electronic transitions. We furthermore critically discuss these models in view of recent results on the structure determination of some gold clusters as well as ligand‐exchange experiments examined by circular dichroism spectroscopy. It is also demonstrated that vibrational circular dichroism can be used to determine the structure of a chiral adsorbate and the way it interacts with the metal. Finally, possible applications of these new chiral materials are discussed.
Impact of ultrafiltration rate on heart rate variability parameters
Authors: Tong Yanqing , Wang Qian , Hou Zhaohui , Sun Jianguo
Published: January 2009

OBJECTIVE

We attempted to study the impact of the ultrafiltration (UF) rate on heart rate variability (HRV) parameters by maintaining sufficient session time, Kt/V, and UF.

METHODS

The 16 Chinese hemodialysis (HD) patients in the study were divided into 3 subgroups according to UF rate: 5 patients in subgroup A with a UF rate ≤0.5 L/h, 7 patients in subgroup B with a UF rate >0.5 L/h and ≤1 L/h, and 4 patients in subgroup C with a UF rate >1 L/h. The research included 3 phases. In the first phase, baseline Holter and blood pressure recording was performed. In the second phase, the patients were admitted for HD with continuous Holter and blood pressure recording. The third phase was after HD with continuous Holter and blood pressure recording. The tape recordings were analyzed by an independent, blinded investigator.

RESULTS

In our study, systolic blood pressure, diastolic blood pressure, and mean arterial pressure remained unchanged in the 3 subgroups before, during, and after the HD process. In HRV, several parameters began to show changes at the start of HD. PNN50 was reduced significantly (p < 0.05) in subgroup C after HD for 3 hours. Subgroups A and B demonstrated the same trend (p < 0.05). The differences between the 3 subgroups were not significant (p > 0.05). The SDNN and low‐frequency/high‐frequency ratio increased significantly (p < 0.05) in subgroup C after HD for 3 hours until 1 hour after HD. The differences were significant compared with the other 2 subgroups (p < 0.05). During the post‐HD state, almost all HRV parameters showed a little recovery to the pre‐HD state.

CONCLUSIONS

Our study suggested a prevalence of sympathetic activity in 4‐hour HD patients with a UF rate >1 L/h, especially at the 3‐hour point during HD. To prevent HD‐related augmented sympathetic activity, prolonged HD sessions with low UF rates (<1 L/h), careful titration of target weight, and low interdialytic weight gain are recommended.
Antitumor effect of substituted quinolines in breast cancer cells
Authors: Gakhar Gunjan , Ohira Takahiro , Shi Aibin , Hua Duy H. , Nguyen Thu Annelise
Published: January 2009

Cancer is caused in part by the disruption in cell homeostasis, affecting the ability to respond to extracellular signals, triggering some intracellular events that affect gap junctional intercellular communication (GJIC). Cancer cells have reduced or altered GJIC capacity. One feasible approach to reduce growth of cancer cells is to enhance/alter the GJIC. The capability of cells to communicate through the gap junction is negatively related to their growth activity. A computational docking study showed that a new class of substituted quinolines designated as PQs had a relatively high binding to gap junction protein, connexin 43. Thus, PQs were used in this study to assess their effect on human breast cancer cells. Scrape load/dye transfer and colony growth assays were performed to measure GJIC and determine the effect of the PQ compounds on colony formation in human normal mammary epithelial cells (HMEC) and breast cancer cells, respectively. PQs had a significant antitumor effect in human breast cancer cells compared with control without treatment or normal mammary epithelial cells. PQ1 (200 nM) showed a 30% increase in the GJIC in T47D cells; however, there was no effect of PQ treatment on GJIC in normal mammary epithelial cells. In addition to an increase in GJIC, 80–95% growth attenuation was observed by PQ1 in colony growth assay. Moreover, an increase in caspase 3 with PQ‐treated cells was observed, suggesting a possible involvement in apoptosis. PQ1‐treated animals showed a significant decrease in xenograft tumor growth of T47D cells in nude mice compared with control or tamoxifen‐treated animals. The results show that PQ1 has a promising role in exerting antitumor activity in human breast cancer cells. Treatment with PQ1 in T47D cells caused an increase in GJIC activity and active caspase 3, and a decrease in colony growth and cell viability. Drug Dev Res 69:526–534, 2008. © 2008 Wiley‐Liss, Inc.
Development of a high‐pressure air‐insulated 72/84‐kV disconnecting switch corresponding to bus‐transfer current switching
Authors: Rokunohe Toshiaki , Yagihashi Yoshitaka , Endo Fumihiro , Oomori Takashi
Published: January 2009

SF6 gas has excellent dielectric strength and current interruption performance. For these reasons, it has been widely used for gas‐insulated switchgear (GIS). Today, such global environmental problems as global warming are important issues of concern. SF6 gas is known as a greenhouse gas with a long atmospheric lifetime, and has global warming potential of 23,900. SF6‐free 72‐kV GIS was recently developed by using high‐pressure air and a gas/solid hybrid structure. But an alternating current disconnecting switch (DS) has yet to be developed thus making this type of SF6‐free 72‐kV GIS unsuitable for double bus‐bar application. Consequently, the development of a high‐pressure air‐insulated DS corresponding to bus‐transfer current switching has been expected. The bus‐transfer current is the highest among all current interruption requirements for the DS. To develop an alternating current DS, efforts must be made to reduce arcing damage to the electrode. This paper describes the fundamental characteristics of current interruption in the plain break type and the magnetic field driven type. Then, average arcing time of the magnetic field driven type was estimated by magnetic flux density. Finally, two types of DS, which were a high‐speed plain break and a low‐speed magnetic field driven, were confirmed to comply with bus‐transfer current switching requirements on JEC standard. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 48–55, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20595
A control method for small‐scale DC power systems including distributed generators
Authors: Ito Youichi , Yang Zhongqing , Akagi Hirofumi
Published: January 2009

This paper describes a DC micro‐grid system interconnecting distributed power generators. The system consists of five generation and control units: a solar‐cell generation unit, a wind‐turbine generation unit, a battery energy‐storage unit, a flywheel power‐leveling unit, and an AC grid‐interconnecting power control unit. The control method is proposed for suppressing the circulating current by detecting only the DC grid voltage. This method brings high reliability, high flexibility, and maintenance‐free operation to the system. The method pays attention to DC output voltage performance of each unit. Each of the power control units and the energy‐storage unit is controlled to act as a voltage source with imaginary impedance. On the other hand, each of the two generation units is controlled to act as a current source. The power‐leveling unit is controlled to act as a current source having the function of frequency selectivity like a high‐pass filter. A 10‐kW prototype system verifies experimentally the validity and effectiveness of the proposed control method for the DC‐grid system. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 86–93, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20603
Current waveform distortion of doubly‐fed generator for wind turbine application by spatial higher harmonics
Authors: Nishihama Kazuo , Ide Kazumasa , Fujigaki Tetsuo , Mizutani Shuji , Iizuka Motonobu
Published: January 2009

This paper describes a method to analyze higher harmonic currents resulting from higher space harmonics, depending on the winding pattern of a doubly‐fed generator. A 1.5‐MW generator was used for the analysis, and the results are compared using finite element magnetic field analysis and measurements.

The result revealed that the proposed analysis, which focuses on the winding pattern and takes into account higher space harmonics, allows us to calculate higher harmonic currents at high precision, understand the mechanism of changing higher harmonic currents due to the slip or the load of the generator and considerably reduce higher harmonic currents at the armature by restricting higher harmonic currents at the magnetic field. In addition, the sensitivity analysis of design parameters clarified the relationship between current distortion and basic characteristics on electric designs. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 79–85, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20606
Evaluation of cost and reliability of power systems with large numbers of distributed generators
Authors: Sasaki Yutaka , Kita Hiroyuki , Tanaka Eiichi , Hasegawa Jun
Published: January 2009

The authors have proposed the Flexible, Reliable and Intelligent ENergy Delivery System (called “FRIENDS”), which is a new concept for future power distribution systems. Also, a “micro grid” which is a similar concept to FRIENDS has been developed. In a micro grid, an independent distribution system can be constituted by a number of distributed generators. In this paper, FRIENDS, Micro grid, and conventional distribution systems are compared quantitatively in supply reliability and system cost through time sequential Monte Carlo simulations. In addition, for cost evaluation, interruption costs are included to show risk incurred by unsupplied energy. Finally, the authors search for preferable form with install and operation of distributed generators and network composition according to social cost including interruption cost and system cost. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 28–37, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20659
Proposal and development of radial air‐gap coreless generator suitable for small wind turbine used in urban area
Authors: Takahashi Toshiyuki , Yasuda Yoh , Ohmoto Shingo , Hara Takehisa
Published: January 2009

Independent distributed power generation using small wind turbines is becoming more widespread as wind power generation increases. Installation of small wind turbines in densely populated urban areas is not only useful from the viewpoint of extracting wind power sources in weak‐wind areas but also for making renewable energy easier to access when power supplies are closer to consumers. It is from this point of view that the authors proposed “urban wind power generation” using a collective system with a number of small vertical wind turbines, and have developed a suitable generator for low‐speed vertical wind turbines such as a Savonius windmill.

Based on a standard coreless generator, the proposed generator is designed to make the direction of the magnetic flux radial in order to install the magnets and coils on the outer end of the generator. The change of magnet composition and flux direction maximizes the speed of the flux change and output voltage within a limited space. With the above configuration, the power of the proposed generator is independent of the diameter.

In this report, the authors describe and evaluate the fundamental performance of a prototype of the proposed generator. Based on the experiments, a maximum output power of 283 W was obtained. The obtained starting torque is small enough to begin rotation under weak wind conditions of no more than 1 m/s. Therefore, it is clear that the proposed “radial” coreless generator is suitable for self‐starting and producing high power at low wind speed. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 26– 34, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20695
Evaluation of costs for procuring reserve capacity in a deregulated power system using multi‐agent model
Authors: Suzuki Satoshi , Kita Hiroyuki , Tanaka Eiichi , Hasegawa Jun
Published: January 2009

In this paper, we assume 2 models for securing reserve capacity. One is “Commitment‐based Security Model” and the other is “Reserve Market‐based Security Model.” In Commitment‐based security model, ISO commits procurement of reserve energy to a particular generation company. Meanwhile, in Reserve market‐based security model, ISO procures reserve energy through reserve market. The main object of this research is to investigate which model will be preferable for the viewpoint of consumer's cost. To compare these models, two things are considered in this paper. One is bidding behavior of agents which bids to energy market and reserve market. To consider this, Q‐Learning of multi‐agent model is used. Also, the Unit Commitment (UC) is considered to calculate generation cost. This is to calculate the cost for securing reserve power more precisely. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 18– 25, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20705