bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical evaluation of serum alpha‐fetoprotein–IgM immune complexes on the diagnosis of primary hepatocellular carcinoma
Authors: Jingting Jiang , Changping Wu , Ning Xu , yibei Zhu , Jun Wu , Mei Ji , Bin Xu , Peter Nilsson‐Ehle , Xueguan Zhang
Published: July 2009

We evaluated clinical significance of serum alpha‐fetoprotein (AFP)‐IgM immune complexes, in comparison with free AFP, on the diagnosis of primary hepatocellular carcinoma (HCC). Serum levels of AFP‐IgM immune complexes and free AFP were determined by the ELISA method and electrochemiluminescence, respectively, in 103 healthy controls, 74 patients suffering from primary HCC, 27 patients suffering from liver cirrhosis, and 63 patients suffering from chronic hepatitis. The best cut‐off value of AFP‐IgM and free AFP for diagnosis of primary HCC were 300 AU/mL and 10 µg/L respectively, according to the area under the curve (AUC) in this study. The sensitivity of AFP‐IgM and free AFP were 64.9 and 79.7%, and the specificity were 75.6 and 80.3%, respectively, when all cases of primary HCC were analyzed, and the AUC of free AFP was larger than that of AFP‐IgM (0.85 vs. 0.72, Z=3.21). However, in case of primary HCC at early stages (stages I and II) were analyzed, the AUC of AFP‐IgM was larger than that of free AFP (0.91 vs. 0.82, Z=1.73), which demonstrated that the sensitivity of AFP‐IgM and free AFP were 94.4 and 72.2%, and the specificity were 81.9 and 79.9%, respectively. When both AFP‐IgM and free AFP were positive, the specificity of diagnosis of primary HCC was 89.1%, and the efficacy was 79.0%. It is concluded that either sensitivity or specificity of serum level of AFP‐IgM immune complexes was higher than that of free AFP in the diagnosis of primary HCC at early stages. As there was false positive AFP‐IgM existed in the patients suffering from cirrhosis and chronic hepatitis, the combination of free AFP and AFP‐IgM could significantly increase specificity and decrease false negative and/or false positive in the primary HCC at early stages. J. Clin. Lab. Anal. 23:213–218, 2009. © 2009 Wiley‐Liss, Inc.
Cancer antigen 125 levels in inflammatory bowel diseases
Authors: Ataseven Hilmi , Öztürk Zeynel Abidin , Arhan Mehmet , Yüksel Osman , Köklü Seyfettin , İbiş Mehmet , Başar Ömer , Yılmaz Fatma Meriç , Yüksel İlhami
Published: July 2009

Background: Cancer antigen 125 (CA‐125) is a tumor marker used for the diagnosis and monitoring of ovarian carcinoma. It can also be elevated in endometriosis, inflammations, and in nongynecological malignancies. Up to date, serum CA‐125 levels in inflammatory bowel diseases (IBD) have not been studied before. Aim: To assess the levels of CA‐125 in patients with ulcerative colitis (UC) and Crohn's disease (CD). Methods: Serum levels of CA‐125 were investigated in 68 cases with UC (male/female: 47/21), 32 CD (male/female: 21/11), and 31 healthy controls (male/female: 16/15). Levels of CA‐125 were also compared among UC patients according to lesion location, severity, and activity of CD. Results: Serum CA‐125 levels were 17.29±24.50 U/ml, 15.56±20.74 U/ml, and 8.85±2.62 U/ml in patients with UC, CD, and healthy controls, respectively. Serum CA‐125 levels were significantly higher in UC compared to control group (P=0.001). Serum CA‐125 levels were higher in CD patients compared to control group but there was no significance (P=0.087). Serum CA‐125 levels were higher in pancolitis compared to distal type and left‐sided UC. Conclusions: Our data suggest that serum CA‐125 levels may be increased in patients with IBDs. J. Clin. Lab. Anal. 23:244–248, 2009. © 2009 Wiley‐Liss, Inc.
Anticardiolipin antibodies in the sera of patients with diagnosed chronic fatigue syndrome
Authors: Hokama Yoshitsugi , Campora Cara Empey , Hara Cynthia , Kuribayashi Tina , Le Huynh Diana , Yabusaki Kenichi
Published: July 2009

Examination of anticardiolipin antibodies (ACAs) in the sera of patients clinically diagnosed with chronic fatigue syndrome (CFS) using an enzyme‐linked immunoassay procedure demonstrated the presence of immunoglobulin M isotypes in 95% of CFS serum samples tested. The presence of immunoglobulin G and immunoglobulin A isotypes were also detected in a subset of the samples. Future studies will focus on elucidating whether alterations to mitochondrial inner membranes and/or metabolic functions play a possible role in the expression of ACAs. J. Clin. Lab. Anal. 23:210–212, 2009. © 2009 Wiley‐Liss, Inc.
Association of β‐1 and β‐2 adrenergic receptor gene polymorphisms with myocardial infarction
Authors: Yilmaz Akin , Kaya Mehmet G. , Merdanoglu Ulgen , Ergun Mehmet A. , Cengel Atiye , Menevse Sevda
Published: July 2009

Both β1‐ and β2‐adrenergic receptors (β1‐ and β2‐AR) have important roles in heart function mainly in response to catecholamines. Some specific polymorphisms in the β1‐ and β2‐AR genes, named ADRB1 and ADRB2, respectively, have been implicated in several cardiovascular and noncardiovascular phenotypes. In this study, we aimed to investigate the possible relationship between Ser49Gly and Arg389Gly polymorphisms of the ADRB1 and Arg16Gly and Gln27Glu polymorphisms of the ADRB2 gene with ST elevation myocardial infarction (MI) in a Turkish population. One hundred patients with ST elevation MI and 100 healthy control subjects were genotyped using the PCR‐RFLP method. Although the Arg389 allele of the ADRB1 gene was associated with an elevated risk of MI, the Glu27 allele of the ADRB2 gene was associated with a decreased risk of MI. Carriers of the ADRB1 Arg389 allele (heterozygotes+homozygotes) had an approximately 3.5‐fold increased risk for MI than Gly389 homozygotes (OR=3.59, 95% CI=0.96–13.47,P=0.045). For the ADRB2 Gln27Glu polymorphism, subjects having one or two copies of the Glu27 allele showed a decreased risk of MI compared with Gln27 homozygote subjects (OR=0.48, 95% CI=0.24–0.94,P=0.03). Haplotype analysis of these polymorphisms showed no significant differences between groups. These results suggest that the Arg389Gly and Gln27Glu polymorphisms may be associated with an altered risk of MI in this Turkish population. J. Clin. Lab. Anal. 23:237–243, 2009. © 2009 Wiley‐Liss, Inc.
A novel and effective multistage classification system for microscopic starch grain images
Authors: Choy Siu‐Kai , Tong Chong‐Sze , Zhao Zhong‐Zhen
Published: July 2009

This article presents a novel and effective multistage system for classifying Chinese Materia Medica microscopic starch grain images. The proposed classification system is constructed based on the Gaussian mixture model‐based clustering, the feature assignment algorithm, and the similarity measurement. Several features for each starch grain image are extracted and every class of drug is represented by a set of characteristic features. For each stage of the system, only one feature is chosen and assigned to that stage via the feature assignment algorithm, and the corresponding characteristic features are subdivided into smaller subsets based on clustering techniques. At the final stage, each subset contains a certain class of drugs (with corresponding characteristic features) and similarity measurement is carried out for starch grain classification. Three sets of the current state‐of‐the‐art starch grain features including the granulometric size distribution, the chord length distribution, and the wavelet signature are used to construct the system. Experimental results on a database of 240 images of 24 classes of drugs reveal the superior performance of the multistage system. Comparison with the traditional starch grain classification approaches indicates that our proposed multistage method produces a marked improvement in classification performance. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.
Functional morphology of the gastric mills of carnivorous, omnivorous, and herbivorous land crabs
Authors: Allardyce Benjamin J. , Linton Stuart M.
Published: July 2009

Terrestrial decapods consume a wide variety of plant and animal material. The potential adaptations of carnivorous, omnivorous, and herbivorous terrestrial crustaceans were studied by examining the functional morphology of the gastric mill. Two closely related species from each feeding preference group were examined to identify which features of the mill were due to phylogeny and which were due to adaptation. The morphology of the gastric mill matched the diet well; the gastric mills of the carnivorous species (Geograpsus grayi and Geograpsus crinipes) possessed a blunt, rounded medial tooth and flattened lateral teeth with a longitudinal grinding groove. These features make them well suited to a carnivorous diet of soft animal tissue as well as hard material, such as arthropod exoskeleton. In contrast, the mill of the herbivorous gecarcinids (Gecarcoidea natalis and Discoplax hirtipes) consisted of a medial tooth with sharp transverse ridges and lateral teeth with sharp interlocking cusps and ridges and no grinding surface. These features would efficiently shred fibrous plant material. The morphology of the mill of the omnivorous coenobitids (Coenobita perlatus and Birgus latro) was more generalized toward a mixed diet. However, the mill of B. latro was more adapted to deal with highly nutritious food items, such as nuts and heavily calcified decapods. Its mill possessed lateral teeth with extended ridges, which sat close to the calcified cardiopyloric valve to form a flattened floor. Hard items trapped in the mill would be crushed against this surface by the medial tooth. J. Morphol. 2010. © 2009 Wiley‐Liss, Inc.
Functional morphology of the palato‐maxillary apparatus in “Palatine dragging” snakes (Serpentes: Elapidae: Acanthophis, Oxyuranus)
Authors: Deufel Alexandra , Cundall David
Published: July 2009

Elapid snakes have previously been divided into two groups (palatine erectors and palatine draggers) based on the morphology and inferred movements of their palatine bone during prey transport (swallowing). We investigated the morphology and the functioning of the feeding apparatus of several palatine draggers (Acanthophis antarcticus, Oxyuranus scutellatus, Pseudechis australis) and compared them to published records of palatine erectors. We found that the palatine in draggers does not move as a straight extension of the pterygoid as originally proposed. The dragger palato‐pterygoid joint flexes laterally with maxillary rotation when the mouth opens and the jaw apparatus is protracted and slightly ventrally during mouth closing. In contrast, in palatine erectors, the palato‐pterygoid joint flexes ventrally during upper jaw protraction. In draggers, the anterior end of the palatine also projects rostrally during protraction, unlike the stability of the anterior end seen in erectors. Palatine draggers differ from palatine erectors in four structural features of the palatine and its relationships to surrounding elements. The function of the palato‐pterygoid bar in both draggers and erectors can be explained by a typical colubroid muscle contraction pattern, which acts on a set of core characters shared among all derived snakes. Although palatine dragging elapids share a fundamental design of the palato‐maxillary apparatus with all higher snakes, they provide yet another demonstration of minor structural modifications producing functional variants. J. Morphol. 2010. © 2009 Wiley‐Liss, Inc.
Atomic force microscopy for cellular level manipulation: imaging intracellular structures and DNA delivery through a membrane hole
Authors: Afrin Rehana , Zohora Umme Salma , Uehara Hironori , Watanabe‐Nakayama Takahiro , Ikai Atsushi
Published: July 2009

The atomic force microscope (AFM) is a versatile tool for imaging, force measurement and manipulation of proteins, DNA, and living cells basically at the single molecular level. In the cellular level manipulation, extraction, and identification of mRNA's from defined loci of a cell, insertion of plasmid DNA and pulling of membrane proteins, for example, have been reported. In this study, AFM was used to create holes at defined loci on the cell membrane for the investigation of viability of the cells after hole creation, visualization of intracellular structure through the hole and for targeted gene delivery into living cells. To create large holes with an approximate diameter of 5–10 µm, a phospholipase A2 coated bead was added to the AFM cantilever and the bead was allowed to touch the cell surface for approximately 5–10 min. The evidence of hole creation was obtained mainly from fluorescent image of Vybrant DiO labeled cell before and after the contact with the bead and the AFM imaging of the contact area. In parallel, cells with a hole were imaged by AFM to reveal intracellular structures such as filamentous structures presumably actin fibers and mitochondria which were identified with fluorescent labeling with rhodamine 123. Targeted gene delivery was also attempted by inserting an AFM probe that was coated with the Monster Green Fluorescent Protein phMGFP Vector for transfection of the cell. Following targeted transfection, the gene expression of green fluorescent protein (GFP) was observed and confirmed by the fluorescence microscope. Copyright © 2009 John Wiley & Sons, Ltd.
Hepatitis B viral loads in southern African Blacks with hepatocellular carcinoma
Authors: Viana Raquel , Wang Renwei , Yu Mimi C. , Welschinger Robert , Chen Chien‐Yu , Kew Michael C.
Published: July 2009

Although viral loads are known to influence the development of hepatitis B virus‐induced hepatocellular carcinoma in a number of populations, little information is available in the Black African population. Black African patients with hepatocellular carcinoma differ from those in other populations in having a lower frequency of e antigen‐positivity and in other respects that might affect viral loads. Hepatitis B viral loads were measured using real‐time polymerase chain reaction assay in 124 Black Africans with hepatocellular carcinoma and compared with those in 125 Black adult asymptomatic viral carriers. The geometric mean viral load in the cancer patients was 553,618 copies/ml (95% CI 301,953–1,015,033 copies/ml), with 62.1% having loads >1 × 105 copies/ml and 87.1% >1 × 104 copies/ml, whereas that in the carriers was 16,084 copies/ml (95% CI 9,184–28,168 copies/ml), with only 15.2% having values >1 × 105 copies/ml and 49.6% >1 × 104 copies/ml (P < 0.001 in each instance). Mean viral load was significantly higher in e antigen‐positive than e antigen‐negative cancer patients (5,905,357 copies/ml [1,362,847–25,588,520] cf 238,173 copies/ml [97,200–685,730]: P < 0.001) after adjusting for age and sex. No statistically significant difference existed between patients in different age groups, in men and women, or in patients infected with genotype A or D after adjusting for the other variables. Conclusion: Black Africans with hepatocellular carcinoma have high hepatitis B viral loads in spite of the relative infrequency of e antigen‐positivity. J. Med. Virol. 81:1525–1530, 2009. © 2009 Wiley‐Liss, Inc.
An animal model for open femur fracture and osteomyelitis—Part II: Immunomodulation with systemic IL‐12
Authors: Lindsey Brock A. , Clovis Nina B. , Smith E. Suzanne , Salihu Sydha , Hubbard David F.
Published: July 2009

Infection resulting from open fracture is a common problem in orthopedics. The purpose of this project was to study the effect of Interleukin‐12 (IL‐12) systemic therapy on a previously established open fracture model. One hundred seven male Sprague‐Dawley rats were assigned to five groups: (1) normal (baseline),(2) control (controlled for anesthesia), (3) fracture, (4) staph, and (5) staph and IL‐12 (SIL). Each group was divided into four time periods: 6, 10, 14, and 21 days after injury and fixation. The operative groups had a standardized femur fracture and fixation using a Kirschner wire as an intramedullary device. The two infection groups (staph and SIL) were inoculated with Staphylococcus aureus following fracture and fixed with an identical technique. The SIL group was treated with systemic IL‐12 for a total of 10 doses over 10 days. Significantly decreased serum IL‐12 levels were noted at day 10 in the operative groups compared to the normal and control groups. The SIL group showed significantly higher macrophage activation levels and total platelet counts at day 21 compared to all the other groups. The overall infection rate was not changed by IL‐12 supplementation; however, bacterial qualitative growth scores were significantly lower in the SIL group at day 10, which corresponded to the lowest level of systemic IL‐12 in the fracture group. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:43–47, 2010
Varve counting reveals high resolution radiocarbon reservoir age variations in palaeolake Lisan
Authors: Prasad Sushma , Negendank J. F. W. , Stein Mordechai
Published: July 2009

The laminated lacustrine sediments deposited in the last glacial Lake Lisan represent annual deposits of primary aragonite and silty detritus that reflect the annual supply of bicarbonate‐bearing freshwater to the lake. A varve‐counting curve was constructed for the time interval of ca. 17.4–22 cal. ka BP based on aragonite U/Th, and atmospheric radiocarbon ages of organic debris recovered from the studied section. Radiocarbon in the primary (evaporitic) aragonite comprises both atmospheric and old carbon (reflecting the reservoir age). The aragonite reservoir ages were determined by comparing the aragonite radiocarbon dates to the varve counting curve, and are found to lie in the range 1900–600 a and display a continuous decline. This opens the possibility for high (annual) resolution monitoring of the reservoir age, similar in quality to tree ring counting, during the upper part of Marine Isotope Stage (MIS) 2. Our work also demonstrates that a ‘uniform’ reservoir age correction is inappropriate when determining the chronology of short‐term climate events in lacustrine environments. Copyright © 2009 John Wiley & Sons, Ltd.
Segmented Block Copolymers with Monodisperse Hard Segments: The Influence of H‐Bonding on Various Properties
Authors: Biemond Gerard J. E. , Feijen Jan , Gaymans Reinoud J.
Published: July 2009

The properties of segmented‐copolymer‐based H‐bonding and non‐H‐bonding crystallisable segments and poly(tetramethylene oxide) segments were studied. The crystallisable segments were monodisperse in length and the non‐hydrogen‐bonding segments were made of tetraamidepiperazineterephthalamide (TPTPT). The polymers were characterised by DSC, FT‐IR, SAXS and DMTA. The mechanical properties were studied by tensile, compression set and tensile set measurements. The TPTPT segmented copolymers displayed low glass transition temperatures (Tg, −70 °C), good low‐temperature properties, moderate moduli (G′ ≈ 10–33 MPa) and high melting temperatures (185–220 °C). However, as compared to H‐bonded segments, both the modulus and the yield stress were relatively low.

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The Calderón approach to an elliptic boundary problem
Authors: Faierman M.
Published: July 2009

We consider a boundary problem for an elliptic system in a bounded region Ω ⊂ ℝn and where the spectral parameter is multiplied by a discontinuous weight function ω (x) = diag(ω1(x), …, ωN (x)). The problem is considered under limited smoothness assumptions and under an ellipticity with parameter condition. Recently, this problem was studied under the assumption that the ωj (x)–1 are essentially bounded in Ω. In this paper we suppose that ω (x) vanishes identically in a proper subregion Ω of Ω and that the ωj (x)–1 are essentially bounded in . Then by using methods which are a variant of those used in constructing the Calderón projectors for the boundary Γ of Ω, we shall derive results here which will enable us in a subsequent work to apply the ideas of Calderón to develop the spectral theory associated with the problem under consideration here (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Closed graph and open mapping theorems for topological $ \tilde \lc $‐modules and applications
Authors: Garetto Claudia
Published: July 2009

We present closed graph and open mapping theorems for $ \tilde \lc $‐linear maps acting between suitable classes of topological and locally convex topological $ \tilde \lc $‐modules. This is done by adaptation of De Wilde's theory of webbed spaces and Adasch–Ernst–Keim's theory of barrelled spaces to the context of locally convex and topological $ \tilde \lc $‐modules, respectively. We give applications of the previous theorems to Colombeau theory as well to the theory of Banach $ \tilde \lc $‐modules. In particular we obtain a necessary condition for 𝒢∞‐hypoellipticity on the symbol of a partial differential operator with generalized constant coefficients (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Poly(3,4‐ethylenedioxythiophene) Derived from Poly(ionic liquid) for the Use as Hole‐Injecting Material in Organic Light‐Emitting Diodes
Authors: Kim TaeYoung , Suh Minwon , Kwon Soon Jae , Lee Tae Hee , Kim Jong Eun , Lee You Jong , Kim Joo Hyung , Hong MunPyo , Suh Kwang S.
Published: July 2009

We report that poly(3,4‐ethylenedioxythiophene) derived from poly(ionic liquid) (PEDOT:PIL) constitutes a unique polymeric hole‐injecting material capable of improving device lifetime in organic light‐emitting diodes (OLEDs). Imidazolium‐based poly(ionic liquid)s were engineered to impart non‐acidic and non‐aqueous properties to PEDOT without compromising any other properties of PEDOT. A fluorescent OLED was fabricated using PEDOT:PIL as a hole‐injection layer and subjected to a performance evaluation test. In comparison with a control device using a conventional PEDOT‐based material, the device with PEDOT:PIL was found to achieve a significant improvement in terms of device lifetime. This improvement was attributed to a lower indium content in the PEDOT:PIL layer, which can be also interpreted as the effective protection characteristics of PEDOT:PIL for indium extraction from the electrodes.

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Factors responsible for force steadiness impairment with fatigue
Authors: Missenard Olivier , Mottet Denis , Perrey Stéphane
Published: July 2009

In this study we investigated the contribution of muscle activation to the impairment of fine force control with fatigue. In three experiments, we manipulated muscle activation and measured force variability before and after a fatigue protocol. When muscle activation was left free (subjects had to match the same absolute force pre‐ and post‐fatigue), fatigue increased muscle activation at moderate force levels only, and force variability increased regardless of the level of force. When muscle activation was controlled (subjects had to match the same electromyographic activity), fatigue no longer increased force variability, except at low force levels. When voluntary muscle activation was suppressed (muscles were electrically stimulated), force variability was unaffected by fatigue. We conclude that the impairment of force steadiness with fatigue is mainly due to the increase in muscle activation at moderate forces, but there are other central sources of force fluctuation present at low force levels. Muscle Nerve, 2009
Long‐term therapy with deflazacort decreases myocardial fibrosis in mdx mice
Authors: Marques Maria Julia , Oggiam Daniella Silva , Barbin Isabel Cristina Chagas , Ferretti Renato , Santo Neto Humberto
Published: July 2009

We evaluated the effects of long‐term administration of deflazacort (DFZ) on the progression of myocardial fibrosis in mdx mice. Mdx mice (6 months old) were treated with DFZ for 15 months. Myocardial fibrosis (MF) was evaluated by histomorphometric methods, and treated and untreated mdx mice of the same age (21 months) were compared. DFZ significantly decreased MF. We conclude that long‐term therapy with DFZ is effective in slowing down the progression of fibrosis in the dystrophin‐deficient heart. Muscle Nerve, 2009
Elicitability of muscle cramps in different leg and foot muscles
Authors: Minetto Marco Alessandro , Botter Alberto
Published: July 2009

To explore the efficacy of muscle motor point stimulation in eliciting muscle cramps, 11 subjects underwent eight sessions of electrical stimulation of the following muscles bilaterally: abductor hallucis flexor hallucis brevis, and both heads of the gastrocnemius muscles. Bursts of 150 square wave stimuli (duration: 152 μs; current intensity: 30% supramaximal) were applied. The stimulation frequency was increased from 4 pulses per second (pps) at increments of 2 pps until a cramp was induced. The number of cramps that could be elicited was smaller in flexor hallucis brevis than in abductor hallucis (16 vs. 22 out of 22 trials each; P < 0.05) and in the lateral gastrocnemius than in the medial gastrocnemius (5 vs. 20 out of 22 trials each; P < 0.0001). We show that leg and foot muscles have different cramp susceptibility, and the intermuscle variability in the elicitability profile for electrically induced cramps supports the use of the proposed method for cramp research. Muscle Nerve, 2009
Comparison of sales and reimbursement data regarding outpatient antibiotic use in a northern Italian Region
Authors: Gagliotti Carlo , Mazzetti Ilaria , Moro Maria Luisa
Published: July 2009

Purpose

To evaluate the accuracy of systemic antibiotic use statistics, based on the reimbursement data of the Emilia‐Romagna Region (Italy), focusing on agents prescribed for urinary tract infections.

Methods

Reimbursement data were obtained from the drug prescription database that includes all outpatient drug prescriptions reimbursed by the Regional Health Service in 2007. Reimbursements were compared to sales data, provided by International Medical Statistics (IMS) Health.

Results

The reimbursement data of the Emilia‐Romagna Region significantly underestimates the actual use of systemic antibiotics when compared to sales. The overall underestimation of antibiotic use is 19%, ranging from 7% for second‐third‐generation cephalosporins to 98% for nitrofurantoin. Considering agents prescribed for urinary tract infections (UTIs), use of nitrofurantoin and sulfamethoxazole‐trimethoprim are more underestimated while fluoroquinolones and fosfomycin are less underestimated than the average for systemic antibiotics.

Conclusions

Sales data from community pharmacies are important for accurate estimation of systemic antibiotic use in Emilia‐Romagna especially for agents, such as nitrofurantoin, purchased without reimbursement in most cases. Copyright © 2009 John Wiley & Sons, Ltd.
Substituent effect on electron affinity, gas‐phase basicity, and structure of monosubstituted propargyl radicals and their anions: a theoretical study
Authors: Lee Gab‐Yong
Published: July 2009

The substituent effect of electron‐withdrawing groups on electron affinity and gas‐phase basicity has been investigated for substituted propargyl radicals and their corresponding anions. It is shown that when a hydrogen of the α‐CH2 group or acetylenic CH in the propargyl system is substituted by an electron‐withdrawing substituent, electron affinity increases, whereas gas‐phase basicity decreases. The calculated electron affinities are 0.95 eV (CHCCH2•), 1.15 eV (CHCCHF•), 1.38 eV (CHCCHCl•), 1.48 eV (CHCCHBr•) for the isomers with terminal CH and 1.66 eV (CFCCH2•), 1.70 eV (CClCCH2•), 1.86 eV (CBrCCH2•) for the isomers with terminal CX at B3LYP level. The calculated gas‐phase basicities for their anions are 378.4 kcal/mol (CHCCH2:−), 371.6 kcal/mol (CHCCHF:−), 365.1 kcal/mol (CHCCHCl:−), 363.5 kcal/mol (CHCCHBr:−) for the isomers with terminal CH and 362.6 kcal/mol (CFCCH2:−), 360.4 kcal/mol (CClCCH2:−), 356.3 kcal/mol (CBrCCH2:−) for the isomers with terminal CX at B3LYP level. It is concluded that the larger the magnitude of electron‐withdrawing, the greater is the electron affinity of radical and the smaller is the gas‐phase basicity of its anion. This tendency of the electron affinities and gas‐phase bacisities is greater in isomers with the terminal CX than isomers with the terminal CH. Copyright © 2009 John Wiley & Sons, Ltd.
Redox‐initiated poly(methyl methacrylate) emulsion polymerizations stabilized with block copolymers based on methoxy‐poly(ethylene glycol), ε‐caprolactone, and linoleic acid
Authors: Tan Boonhua , Nabuurs Tijs , Feijen Jan , Grijpma Dirk W.
Published: July 2009

A redox initiating system, consisting of t‐butyl hydroperoxide (tBHPO), isoascorbic acid (iAA), and ethylenediaminetetraacetic acid ferric‐sodium salt (FeEDTA) was employed in emulsion polymerizations of methyl methacrylate (MMA) at high solids contents of 30 wt % in water. The system was stabilized using, linoleic acid (LA)‐functionalized and nonfunctionalized surfactants based on methoxy‐PEG (MPEG) and ε‐caprolactone (CL). To optimize polymerization conditions and to avoid coagulation and solidification during the reaction, the temperature, the amount of initiator, the chemical characteristics of the surfactant, and the surfactant to monomer ratio were varied. MPEO45‐CL6.5‐LA (the subscripts refer to the average number of repeating monomer units) was found to be the most suitable surfactant, as it performs adequately under suboptimal reaction conditions. In the emulsion polymerization of MMA in water at ∼30 wt %, best results were obtained at a reaction temperature of 60 °C, with an initiator system comprising tBHPO iAA and FeEDTA, and a surfactant to monomer ratio of 10/90 by weight or higher. Under these conditions, stable PMMA latices with average particle sizes of 200–300 nm were obtained at complete monomer conversion. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4234–4244, 2009
Synthesis of dendritic carbohydrate end‐functional polymers via RAFT: Versatile multi‐functional precursors for bioconjugations
Authors: Xu Jiangtao , Boyer Cyrille , Bulmus Volga , Davis Thomas P.
Published: July 2009

Well‐defined pyridyl disulfide (PDS) end‐functionalized polymer‐dendritic carbohydrate scaffolds are reported as novel precursors for the attachment of biomolecules. This synthetic approach combines reversible addition fragmentation chain transfer (RAFT) polymerization and “click” reactions. Poly(N‐(2‐hydroxypropyl) methacrylamide) (PHPMA) with 2‐mercaptothiozalidine end‐groups was prepared by RAFT polymerization yielding molecular weights of Mn = 4300 and 9900, both with a polydispersity of less than 1.2. These polymers were then attached to dendritic mannose scaffolds preconstructed via consecutive “click” reactions. Finally, the ω‐dithiobenzoate RAFT end‐group of PHPMA was modified to yield PDS functionality, by aminolysis in the presence of 2,2′‐dithiodipyridine. This PDS end‐functionalized PHPMA‐dendritic carbohydrate scaffold is a versatile precursor for bioconjugations, as the synthetic procedure can easily accommodate a range of sugar functionalities. In addition, the PDS groups can be used to react with any thiol present in a biomolecule (e.g., cysteine residue in proteins, or SH terminal nucleotides). To demonstrate the utility of these scaffolds we describe their bioconjugation to short interfering RNA. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4302–4313, 2009
Postpolymerization modification of poly(pentafluorophenyl methacrylate): Synthesis of a diverse water‐soluble polymer library
Authors: Gibson Matthew I. , Fröhlich Eleonore , Klok Harm‐Anton
Published: July 2009

This article explores the feasibility of poly(pentafluorophenyl methacrylate) (PPFMA) prepared by reversible addition fragmentation chain transfer (RAFT) polymerization as a platform for the preparation of diverse libraries of functional polymers via postpolymerization modification with primary amines. Experiments with a broad range of functional amines and PPFMA precursors of different molecular weights indicated that the postpolymerization modification reaction proceeds with good to excellent conversion for a diverse variety of functional amines and is essentially independent of the PPFMA precursor molecular weight. The RAFT end group, which was well preserved throughout the polymerization, is cleaved during postpolymerization modification to generate a thiol end group that provides possibilities for further orthogonal chain‐end modification reactions. The degree of postpolymerization modification can be controlled by varying the relative amount of primary amine that is used and random polymethacrylamide copolymers can be prepared via a one‐pot/two‐step sequential addition procedure. Cytotoxicity experiments revealed that the postpolymerization modification strategy does not lead to any additional toxicity compared with the corresponding polymer obtained via direct polymerization, which makes this approach also of interest for the synthesis of biologically active polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4332–4345, 2009
Spectroscopic investigations on polypropylene‐carbon nanofiber composites. I. Raman and electron spin resonance spectroscopy
Authors: Chipara Mircea , Villarreal John R. , Chipara Magdalena Dorina , Lozano Karen , Chipara Alin Cristian , Sellmyer David J.
Published: July 2009

Isotactic polypropylene‐vapor grown carbon nanofiber composites containing various fractions of carbon nanofibers, ranging from 0 to 20 wt %, have been prepared. Raman spectroscopy was used to analyze the effect of the dispersion of carbon nanofibers within polypropylene and the interactions between carbon nanofibers and macromolecular chains. The as‐recorded Raman spectra have been successfully fitted by a linear convolution of Lorentzian lines. Changes of the Raman lines parameters (position, intensity, width, and area) of polypropylene and carbon nanofibers were analyzed in detail. The Raman spectra of the polymeric matrix—at low concentrations of nanofibers—show important modifications that indicate strong interactions between carbon nanofibers and the polymeric matrix reflecting by vibrational dephasing of macromolecular chains. The Raman spectrum of carbon nanofibers is sensitive to the loading with carbon nanofibers, showing changes of the resonance frequencies, amplitudes, and width for both D‐ and G‐bands. Raman data reveals the increase of the disorder, as the concentration of carbon nanofibers is increased. The presence of the typical ESR line assigned to conducting electrons delocalized over carbon nanofibers is confirmed and the presence of a spurious magnetic line due to catalyst's residues is reported. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1644–1652, 2009
Molecular weight dependence of fiber structure development in the laser drawing of poly(ethylene terephthalate) fibers
Authors: Kim Kyoung Hou , Yamaguchi Takayoshi , Ohkoshi Yutaka , Gotoh Yasuo , Nagura Masanobu , Urakawa Hiroshi , Kotera Masaru , Kikutani Takeshi
Published: July 2009

The effect of molecular weight on fiber structure development during the continuous neck‐drawing of the amorphous poly(ethylene terephthalate) (PET) fiber was investigated by fiber temperature measurements and online WAXD analysis. The fiber temperature was also simulated using the energy balance equation. The simulated temperature increased differently with molecular weight immediately after the neck point, while the measured temperature showed no difference. The difference in the simulated temperature was caused by the potential energy increase with increasing molecular weight, which would result in a retardation effect in the initial stage of fiber structure development. Online X‐ray measurements were carried out with a time resolution of 0.5 ± 0.06 ms. A two‐dimensionally ordered mesophase was formed within 1 ms after the neck point and developed into a microfibrillar structure. The time required for the disappearance of the two‐dimensionally ordered structure increased with increasing molecular weight, leading to a retardation effect. No molecular weight dependence was observed in the rate of transformation from the two‐dimensionally ordered structure to the PET crystal. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1653–1665, 2009
Study of Nanoparticles Formation in a Pulsed Magnetron Discharge in Acetylene
Authors: De Vriendt Valérie , Maseri Fabrizio , Nonet Aurélien , Lucas Stéphane
Published: July 2009

The aim of this work is to study in a pulsed magnetron discharge of acetylene at 10−1 Torr, the influence of tOFF parameter on roughness and morphology of films deposited on silicon substrates. By using a low power discharge (long tOFF and short tON for a given power), a coating with unique morphology is deposited. This film is formed of nanoparticles and particular agglomerates called ‘flowers’ of micrometric size. To the best of our knowledge, it's the first time that such ‘flowers’ structures have been observed for a pulsed plasma polymerization of acetylene. According to the obtained results in mass spectrometry of plasma, nanoparticles and ‘flowers’ are probably formed in gas phase. A growth mechanism in several steps is proposed.
PO4046‐Hard Coatings with High Film Thickness Prepared by PVD
Authors: Zimmer Otmar , Kaulfuß Frank
Published: July 2009

Classical hard coatings such as nitrides, oxides, or carbon coatings are normally used in a thickness range of under 10 µm. The preparation of such coatings can properly be handled in the industry and their coating properties can be well adjusted. Such coatings are used for wear resistant coatings of tools and components. For example, specific cutting applications are only possible by using a high performance hard coating. The preparation of thicker coatings is a demanding task, among others, for the following reasons. Most of the coating materials have a high level of intrinsic stress. At elevated coating thicknesses, the coatings tend to form cracks or to delaminate. Also an inhomogeneous film structure can be observed in many cases. Furthermore, the preparation of thicker films by PVD is a very time‐consuming operation. Nevertheless, thicker films are very interesting for many applications. One can, for example, achieve a remarkable longer lifetime of coated components. Another possibility is the mechanical post‐treatment of a coated part to sharpen a coated cutting edge or to create a special geometry. Precondition is a thick coating without growth defects and sufficient mechanical properties such as hardness, toughness, and temperature stability. This paper contributes to clarifying the problem and to discuss the possibilities to face the task.
Properties of (Ti,Al,Si)N coatings for high demanding metal cutting applications deposited by HPPMS in an industrial coating unit
Authors: Bobzin Kirsten , Bagcivan Nazlim , Immich Philipp , Bolz Stephan , Fuß Hans Gerd , Cremer Rainer
Published: July 2009

Hard and smooth coatings with high oxidation resistance and thermal stability are used for economical machining. In this regard, nc‐(Ti,Al)N/a‐Si3N4 films were sputtered on tungsten carbide cutting inserts and WC/Co samples by using an industrial CC800/9 high power pulse magnetron sputtering (HPPMS) coating unit. Coating composition and mechanical properties were investigated by scanning electron microscopy (EDS) and nano‐indentation. Hardness was about 36 GPa for a silicon content of about 9.6 at%. Optical emission spectroscopy (OES) was done to detect the ionization fraction of deposition species and to compare it to direct current (dc). Deposition rate of the HPPMS coatings was 1.6 times higher on areas positioned orthogonal to the target compared to dc sputtered coatings. Finally cutting performance was compared to a state‐of‐the‐art coating in turning HSS (high speed steel) under severe conditions. After the cutting tests SEM pictures were taken at the flank side of the cutting inserts to detect the wear. Cutting results show enhanced cutting performance due to the application of the HPPMS‐technology resulting in denser structure, higher hardness, smoother surface and better thickness uniformity compared to dc.
Microstructural Characterization of In‐flight Particles in Plasma Spray Process
Authors: Tekmen Cagri , Tsunekawa Yoshiki , Yoshida Masashi , Okumiya Masahiro
Published: July 2009

Oxidation behavior of in‐flight particle in plasma spray process significantly affects the coating properties and performance. Therefore, understanding the relationship between in‐flight particle characteristics and oxidation phenomena is essential to improve the coating properties. This paper presents the oxidation behavior of in‐flight aluminum particles and its relationship between in‐flight particle temperature and velocity. Aluminum powder was injected into the plasma flame at different spray conditions and collected at different stand‐off distances by using a specially designed equipment. It has been observed that in‐flight particle velocity is the main parameter that affects the oxidation of aluminum particles.
Combining crystallography and molecular dynamics: The case of Schistosoma mansoni phospholipid glutathione peroxidase
Authors: Dimastrogiovanni Daniela , Anselmi Massimiliano , Miele Adriana Erica , Boumis Giovanna , Petersson Linn , Angelucci Francesco , Nola Alfredo Di , Brunori Maurizio , Bellelli Andrea
Published: July 2009

Oxidative stress is a widespread challenge for living organisms, and especially so for parasitic ones, given the fact that their hosts can produce reactive oxygen species (ROS) as a mechanism of defense. Thus, long lived parasites, such as the flatworm Schistosomes, have evolved refined enzymatic systems capable of detoxifying ROS. Among these, glutathione peroxidases (Gpx) are a family of sulfur or selenium‐dependent isozymes sharing the ability to reduce peroxides using the reducing equivalents provided by glutathione or possibly small proteins such as thioredoxin. As for other frontline antioxidant enzymatic systems, Gpxs are localized in the tegument of the Schistosomes, the outermost defense layer. In this article, we present the first crystal structure at 1.0 and 1.7 Å resolution of two recombinant SmGpxs, carrying the active site mutations Sec43Cys and Sec43Ser, respectively. The structures confirm that this enzyme belongs to the monomeric class 4 (phospholipid hydroperoxide) Gpx. In the case of the Sec to Cys mutant, the catalytic Cys residue is oxidized to sulfonic acid. By combining static crystallography with molecular dynamics simulations, we obtained insight into the substrate binding sites and the conformational changes relevant to catalysis, proposing a role for the unusual reactivity of the catalytic residue. Proteins 2010. © 2009 Wiley‐Liss, Inc.
gCOMBINE: A graphical user interface to perform structure‐based comparative binding energy (COMBINE) analysis on a set of ligand‐receptor complexes
Authors: Gil‐Redondo Rubén , Klett Javier , Gago Federico , Morreale Antonio
Published: July 2009

We present gCOMBINE, a Java‐written graphical user interface (GUI) for performing comparative binding energy (COMBINE) analysis (Ortiz et al. J Med Chem 1995; 38:2681–2691) on a set of ligand‐receptor complexeswith the aim of deriving highly informative quantitative structure‐activity relationships. The essence of the method is to decompose the ligand‐receptor interaction energies into a series of terms, explore the origins of the variance within the set using Principal Component Analysis, and then assign weights to selected ligandresidue interactions using partial least squares analysis to correlate with the experimental activities or binding affinities. The GUI allows plenty of interactivity and provides multiple plots representing the energy descriptors entering the analysis, scores, loadings, experimental versus predicted regression lines, and the evolution of parameterssuch as r2 (correlation coefficient), q2 (cross‐validated r2), and prediction errors as the number of extracted latent variables increases. Other representative features include the implementation of a sigmoidal dielectric function for electrostatic energy calculations, alternative cross‐validation procedures (leave‐N‐out and random groups), drawing of confidence ellipses, and the possibility to carry out several additional tasks such as optional truncation of positive interaction energy values and generation of ready‐to‐use PDB files containing information related to the importance for activity of individual protein residues. This information can be displayed and color‐coded using a standard molecular graphics program such as PyMOL. It is expected that this user‐friendly tool will expand the applicability of the COMBINE analysis method and encourage more groups to use it in their drug design research programs. Proteins 2010. © 2009 Wiley‐Liss, Inc.
RigidFinder: A fast and sensitive method to detect rigid blocks in large macromolecular complexes
Authors: Abyzov Alexej , Bjornson Robert , Felipe Mihali , Gerstein Mark
Published: July 2009

Advances in structure determination have made possible the analysis of large macromolecular complexes (some with nearly 10,000 residues, such as GroEL). The large‐scale conformational changes associated with these complexes require new approaches. Historically, a crucial component of motion analysis has been the identification of moving rigid blocks from the comparison of different conformations. However, existing tools do not allow consistent block identification in very large structures. Here, we describe a novel method, RigidFinder, for such identification of rigid blocks from different conformations—across many scales, from large complexes to small loops. RigidFinder defines rigidity in terms of blocks, where inter‐residue distances are conserved across conformations. Distance conservation, unlike the averaged values (e.g., RMSD) used by many other methods, allows for sensitive identification of motions. A further distinguishing feature of our method, is that, it is capable of finding blocks made from nonconsecutive fragments of multiple polypeptide chains. In our implementation, we utilize an efficient quasi‐dynamic programming search algorithm that allows for real‐time application to very large structures. RigidFinder can be used at a dedicated web server (http://rigidfinder.molmovdb.org). The server also provides links to examples at various scales such as loop closure, domain motions, partial refolding, and subunit shifts. Moreover, here we describe the detailed application of RigidFinder to four large structures: Pyruvate Phosphate Dikinase, T7 RNA polymerase, RNA polymerase II, and GroEL. The results of the method are in excellent agreement with the expert‐described rigid blocks. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Conformational selection and collagenolysis in Type III collagen
Authors: Salsas‐Escat Ramon , Stultz Collin M.
Published: July 2009

Matrix metalloproteases (MMPs) cleave native collagen at a single site despite the fact that collagen contains more than one scissile bond that can, in principle, be cleaved. For peptide bond hydrolysis to occur at one specific site, MMPs must (1) localize to a region near the unique scissile bond, (2) bind residues at the catalytic site that form the scissile bond, and (3) hydrolyze the corresponding peptide bond. Prior studies suggest that for some types of collagen, binding of noncatalytic MMP domains to amino acid sequences in the vicinity of the true cleavage site facilitates the localization of collagenases. In the present study, our goal was to determine whether binding to the catalytic site also plays a role in determining MMP specificity. To investigate this, we computed the conformational free energy landscape of Type III collagen at each potential cleavage site. The free energy profiles suggest that although all potential cleavage sites sample unfolded states at relatively low temperatures, the true cleavage site samples structures that are complementary to the catalytic site. By contrast, potential cleavage sites that are not cleaved sample states that are relatively incompatible with the MMP active site. Furthermore, our findings point to a specific role for arginine residues in modulating the structural stability of collagen near the collagenase cleavage site. These data imply that locally unfolded potential cleavage sites in Type III collagen sample distinct unfolded ensembles, and that the region about the true collagenase cleavage site samples states that are most complementary to the MMP active site. Proteins 2010. © 2009 Wiley‐Liss, Inc.