bluuebunny/crossref_metadata_2025 huggingface dataset:
Li- and Er-codoped ZnO with enhanced 1.54μm photoemission
Authors: Zhou Zhen , Komori Toshitaka , Ayukawa Tatsuya , Yukawa Hiroshi , Morinaga Masahiko , Koizumi Atsushi , Takeda Yoshikazu
Published: August 2005

Lithium ions were introduced into Er-doped ZnO specimens, and the codoping effect was investigated on the photoluminescence (PL) spectra around 1.54μm. It was found that the Li addition increased the PL intensity by about 90 times at most, and also the strongest peak position shifted from 1.534μm to 1.539μm. The enhancement in the PL intensity could be attributed to the modification of the local symmetry and structure around Er3+ by Li ions. The Li ions can be introduced easily into the Er-doped ZnO and other semiconductor hosts, and is therefore a very useful element in the practical fabrication of the optoelectronic devices.
Vacuum laser-driven acceleration by two slits-truncated Bessel beams
Authors: Li D. , Imasaki K.
Published: August 2005

An approach of vacuum acceleration by two laser Bessel beams is presented in this letter. With elaborate arrangement, the two Bessel beams are truncated by a set of special annular slits to form consecutive acceleration field in the electron traveling direction. Therefore, the electron of a certain initial energy can be accelerated in the whole interaction region without experiencing deceleration even though the phase-slippage occurs. Furthermore, the Bessel beam can provide a rather long distance for the effective interaction between the electron and the laser field due to its “diffraction-free” property, resulting in improvement of the energy exchange.
Pulsed-ion-beam nitriding and smoothing of titanium surface in a vacuum
Authors: Zhu X. P. , Suematsu Hisayuki , Jiang Weihua , Yatsui Kiyoshi , Lei M. K.
Published: August 2005

Both nitriding and smoothing of titanium have been achieved under irradiation of intense pulsed ion beam in a vacuum of 2×10−2Pa. Applying a screening method, we find that medium ion-beam intensity and multi-shot irradiation are effective for the processing, where repetitive surface melting with limited ablation favored Ti nitride formation as well as surface smoothing. The present results demonstrate that ambient gas atoms∕molecules can be efficiently incorporated in metal matrices to form compounds under the ion-beam irradiation. The finding is of great significance for extending application scope of the ion-beam technique in materials research and processing, combined with the recent success in introducing ambient gas into the processing chamber.
Intersubband transitions in proton irradiated InGaAs∕GaAs multiple quantum dots
Authors: Chua Ying Chao , Decuir E. A. , Manasreh M. O. , Weaver B. D.
Published: August 2005

The optical absorbance spectra of the intersubband transition in 3 MeV proton irradiated In0.3Ga0.7As∕GaAs multiple quantum dot samples, cut from the same wafer, were investigated as a function of irradiation dose. The intensity of the intersubband transition is observed to decrease as the irradiation dose is increased. The behavior of the intersubband transition in irradiated In0.3Ga0.7As∕GaAs multiple quantum dot samples is compared to those of intersubband transitions in irradiated GaAs∕AlGaAs and InGaAs∕InAlAs multiple quantum well samples. The intersubband transition absorbance spectrum was completely depleted in a multiple quantum dot sample irradiated with 5×1014cm−2. Post-irradiation thermal annealing was performed on the latter sample where thermal annealing recovery of the depleted intersubband transition was not observed. Instead, a broadband with a peak at 5μm is observed after annealing the sample at 500 °C for 15 min. The absence of the broadband in an unirradiated sample that was subject to the same annealing conditions suggests that this band may be related to irradiation-induced defects.
Measurement of junction temperature in GaN-based laser diodes using voltage-temperature characteristics
Authors: Ryu Han-Youl , Ha Kyoung-Ho , Chae Jung-Hye , Nam Ok-Hyun , Park Yong-Jo
Published: August 2005

We present a method to determine junction temperature in GaN-based laser diodes (LDs) for simple, fast, and reliable characterization of thermal properties. The large change of forward operation voltage with temperature in GaN laser diodes is advantageously used to measure junction temperature. Using this method, we compare junction temperature of LD structures with different substrates and chip mounting methods. It is found that the junction temperature can be reduced considerably by employing GaN substrates or epi-down bonding. For epi-down bonded LDs, as much as two-fold reduction in junction temperature is achieved compared to epi-up bonded ones and junction temperature rise in this case is only about 13 degrees for more than 100 mW-output power.
Transport properties of InN nanowires
Authors: Chang Chih-Yang , Chi Gou-Chung , Wang Wei-Ming , Chen Li-Chyong , Chen Kuei-Hsien , Ren F. , Pearton S. J.
Published: August 2005

The transport properties of single InN nanowires grown by thermal catalytic chemical vapor deposition were measured as a function of both length/square of radius ratio and temperature. The resistivity of the n-type InN nanowires with diameter >100nm was measured by the transmission line method and the value was on the order of 4×10−4Ωcm. The specific contact resistivity for unalloyed Pd∕Ti∕Pt∕Au ohmic contacts was near 1.09×10−7Ωcm2. The temperature dependence of resistance showed a positive temperature coefficient and a functional form characteristic of metallic conduction in the InN.
The Smk1p MAP kinase negatively regulates Gsc2p, a 1,3-β-glucan synthase, during spore wall morphogenesis in
Saccharomyces cerevisiae
Authors: Huang Linda S. , Doherty Hugh K. , Herskowitz Ira
Published: August 2005

Spore formation in
Saccharomyces cerevisiae
involves the sequential deposition of multiple spore wall layers between the prospore membranes that surround each meiotic product. The Smk1p mitogen-activated protein (MAP) kinase plays a critical role in spore formation, but the proteins that interact with Smk1p to regulate spore morphogenesis have not been described. Using mass spectrometry, we identify Gsc2p as a Smk1p-associated protein. Gsc2p is a 1,3-β-glucan synthase subunit involved in synthesizing an inner spore wall layer. We find that 1,3-β-glucan synthase activity is elevated in
smk1
mutants, suggesting that
SMK1
negatively regulates
GSC2
. Although deposition of the two inner spore wall layers is normal in
smk1
mutants, deposition of the outer layers is aberrant. However, eliminating
GSC2
activity restores normal deposition of the third spore wall layer in
smk1
mutants, indicating that negative regulation of
GSC2
by
SMK1
is important for spore wall deposition. Our findings suggest a model for the coordination of spore wall layer deposition in which Smk1p facilitates the transition between early and late phases of spore wall deposition by inhibiting a spore wall-synthesizing enzyme important for early phases of spore wall deposition.
Xenopus
TRPN1 (NOMPC) localizes to microtubule-based cilia in epithelial cells, including inner-ear hair cells
Authors: Shin Jung-Bum , Adams Dany , Paukert Martin , Siba Maria , Sidi Samuel , Levin Michael , Gillespie Peter G. , Gründer Stefan
Published: August 2005

In vertebrates, the senses of hearing and balance depend on hair cells, which transduce sounds with their hair bundles, containing actin-based stereocilia and microtubule-based kinocilia. A longstanding question in auditory science is the identity of the mechanically sensitive transduction channel of hair cells, thought to be localized at the tips of their stereocilia. Experiments in zebrafish implicated the transient receptor potential (TRP) channel NOMPC (drTRPN1) in this role; TRPN1 is absent from the genomes of higher vertebrates, however, and has not been localized in hair cells. Another candidate for the transduction channel, TRPA1, apparently is required for transduction in mammalian and nonmammalian vertebrates. This discrepancy raises the question of the relative contribution of TRPN1 and TRPA1 to transduction in nonmammalian vertebrates. To address this question, we cloned the TRPN1 ortholog from the amphibian
Xenopus laevis
, generated an antibody against the protein, and determined the protein's cellular and subcellular localization. We found that TRPN1 is prominently located in lateral-line hair cells, auditory hair cells, and ciliated epidermal cells of developing
Xenopus
embryos. In ciliated epidermal cells TRPN1 staining was enriched at the tips and bases of the cilia. In saccular hair cells, TRPN1 was located prominently in the kinocilial bulb, a component of the mechanosensory hair bundles. Moreover, we observed redistribution of TRPN1 upon treatment of hair cells with calcium chelators, which disrupts the transduction apparatus. This result suggests that although TRPN1 is unlikely to be the transduction channel of stereocilia, it plays an essential role, functionally related to transduction, in the kinocilium.
Archaeological and chemical evidence for early salt production in China
Authors: Flad Rowan , Zhu Jiping , Wang Changsui , Chen Pochan , von Falkenhausen Lothar , Sun Zhibin , Li Shuicheng
Published: August 2005

Salt production and trade is thought to be critical to the development of all states and emergent empires. Until now, however, scientific evidence of early salt production has rarely been presented, and no studies of early Chinese salt production have provided unequivocal proof. Here, we report x-ray fluorescence, x-ray diffraction, and scanning electron microscopy (SEM) analyses that demonstrate that salt was the primary product during the first millennium before Christ (B.C.) at Zhongba in Central China. This work provides an early example of salt production discovered in China and presents a methodology for evaluating salt production sites in other regions.
Marine T4-type bacteriophages, a ubiquitous component of the dark matter of the biosphere
Authors: Filée Jonathan , Tétart Françoise , Suttle Curtis A. , Krisch H. M.
Published: August 2005

Tailed bacteriophages are the most abundant biological entities in marine environments. However, most of these marine phages are uncharacterized because few of their hosts have been cultivated. To learn more about such phages, we designed a set of degenerate PCR primers for phage T4 g23, which encodes the major capsid protein in all of the T4-type phages, an important family of the tailed phage. These primers were used to amplify g23-related sequences from diverse marine environments (fjords and bays of British Columbia, the eastern Gulf of Mexico, and the western Arctic Ocean) revealing a remarkable level of molecular diversity, which in some cases was correlated with morphological variation of the virions. Phylogenetic analysis showed that although some of these sequences were closely related to well studied subgroups of the T4-type phage, such as the T-evens, the majority of them belong to five previously uncharacterized subgroups. These data indicate that the host range of T4-type phages is much broader than previously imagined and that the laboratory isolate T4 belongs to a phage family that is extraordinarily widespread and diverse in the biosphere.
Atypical PKCι contributes to poor prognosis through loss of apical-basal polarity and Cyclin E overexpression in ovarian cancer
Authors: Eder Astrid M. , Sui Xiaomei , Rosen Daniel G. , Nolden Laura K , Cheng Kwai Wa , Lahad John P. , Kango-Singh Madhuri , Lu Karen H. , Warneke Carla L. , Atkinson Edward N. , Bedrosian Isabelle , Keyomarsi Khandan , Kuo Wen-lin , Gray Joe W. , Yin Jerry C. P. , Liu Jinsong , Halder Georg , Mills Gordon B.
Published: August 2005

We show that atypical PKCι, which plays a critical role in the establishment and maintenance of epithelial cell polarity, is genomically amplified and overexpressed in serous epithelial ovarian cancers. Furthermore, PKCι protein is markedly increased or mislocalized in all serous ovarian cancers. An increasedPKCι DNA copy number is associated with decreased progression-free survival in serous epithelial ovarian cancers. In aDrosophila in vivoepithelial tissue model, overexpression of persistently active atypical PKC results in defects in apical-basal polarity, increased Cyclin E protein expression, and increased proliferation. Similar to theDrosophilamodel, increased PKCι proteins levels are associated with increased Cyclin E protein expression and proliferation in ovarian cancers. In nonserous ovarian cancers, increased PKCι protein levels, particularly in the presence of Cyclin E, are associated with markedly decreased overall survival. These results implicate PKCι as a potential oncogene in ovarian cancer regulating epithelial cell polarity and proliferation and suggest that PKCι is a novel target for therapy.
The complete genome sequence ofMycobacterium aviumsubspeciesparatuberculosis
Authors: Li Lingling , Bannantine John P. , Zhang Qing , Amonsin Alongkorn , May Barbara J. , Alt David , Banerji Nilanjana , Kanjilal Sagarika , Kapur Vivek
Published: August 2005

We describe here the complete genome sequence of a common clone ofMycobacterium aviumsubspeciesparatuberculosis(Map) strain K-10, the causative agent of Johne's disease in cattle and other ruminants. The K-10 genome is a single circular chromosome of 4,829,781 base pairs and encodes 4,350 predicted ORFs, 45 tRNAs, and one rRNA operon.In silicoanalysis identified >3,000 genes with homologs to the human pathogen,M. tuberculosis(Mtb), and 161 unique genomic regions that encode 39 previously unknownMapgenes. Analysis of nucleotide substitution rates withMtbhomologs suggest overall strong selection for a vast majority of these shared mycobacterial genes, with only 68 ORFs with a synonymous to nonsynonymous substitution ratio of >2. Comparative sequence analysis reveals several noteworthy features of the K-10 genome including: a relative paucity of the PE/PPE family of sequences that are implicated as virulence factors and known to be immunostimulatory duringMtbinfection; truncation in the EntE domain of a salicyl-AMP ligase (MbtA), the first gene in the mycobactin biosynthesis gene cluster, providing a possible explanation for mycobactin dependence ofMap; andMap-specific sequences that are likely to serve as potential targets for sensitive and specific molecular and immunologic diagnostic tests. Taken together, the availability of the complete genome sequence offers a foundation for the study of the genetic basis for virulence and physiology inMapand enables the development of new generations of diagnostic tests for bovine Johne's disease.
Pleiotrophin regulates serine phosphorylation and the cellular distribution of β-adducin through activation of protein kinase C
Authors: Pariser Harold , Herradon Gonzalo , Ezquerra Laura , Perez-Pinera Pablo , Deuel Thomas F.
Published: August 2005

Pleiotrophin (PTN) was found to regulate tyrosine phosphorylation of β-adducin through the PTN/receptor protein tyrosine phosphatase (RPTP)β/ζ signaling pathway. We now demonstrate that PTN stimulates the phosphorylation of serines 713 and 726 in the myristoylated alanine-rich protein kinase (PK) C substrate domain of β-adducin through activation of either PKC α or β. We also demonstrate that PTN stimulates translocation of phosphoserine 713 and 726 β-adducin either to nuclei, where it associates with nuclear chromatin and with centrioles of dividing cells, or to a membrane-associated site, depending on the phase of cell growth. Furthermore, we demonstrate that PTN stimulates the degradation of β-adducin in PTN-stimulated cells. Phosphorylation of serines 713 and 726 in β-adducin is known to markedly reduce the affinity of β-adducin for spectrin and actin and to uncouple actin/spectrin/β-adducin multimeric complexes needed for cytoskeletal stability. The data thus suggest that the PTN-stimulated phosphorylation of serines 713 and 726 in β-adducin disrupts cytoskeletal protein complexes and integrity, features demonstrated in both PTN-stimulated cells and of highly malignant cells that constitutively express the endogenous
Ptn
gene. The data also support the important conclusion that PTN determines the cellular location of β-adducin phosphorylated in serines 713 and 726 and raise the possibility that β-adducin functions in support of structure of heterochromatin and centrioles during mitosis.
Cultural variation in eye movements during scene perception
Authors: Chua Hannah Faye , Boland Julie E. , Nisbett Richard E.
Published: August 2005

In the past decade, cultural differences in perceptual judgment and memory have been observed: Westerners attend more to focal objects, whereas East Asians attend more to contextual information. However, the underlying mechanisms for the apparent differences in cognitive processing styles have not been known. In the present study, we examined the possibility that the cultural differences arise from culturally different viewing patterns when confronted with a naturalistic scene. We measured the eye movements of American and Chinese participants while they viewed photographs with a focal object on a complex background. In fact, the Americans fixated more on focal objects than did the Chinese, and the Americans tended to look at the focal object more quickly. In addition, the Chinese made more saccades to the background than did the Americans. Thus, it appears that differences in judgment and memory may have their origins in differences in what is actually attended as people view a scene.
The effect of whey acidic protein fractions on bone loss in the ovariectomised rat
Authors: Kruger Marlena C. , Plimmer Gabrielle G. , Schollum Linda M. , Haggarty Neill , Ram Satyendra , Palmano Kate
Published: August 2005

Bovine milk has been shown to contain bioactive components with bone-protective properties. Earlier studies on bovine milk whey protein showed that it suppressed bone resorption in the female ovariectomised rat. A new osteotropic component was subsequently identified in the whey basic protein fraction, but bone bioactivity may also be associated with other whey fractions. In the present study, we investigated whether acidic protein fractions isolated from bovine milk whey could prevent bone loss in mature ovariectomised female rats. Six-month-old female rats were ovariectomised (OVX) or left intact (sham). The OVX rats were randomised into four groups. One group remained the control (OVX), whereas three groups were fed various whey acidic protein fractions from milk whey as 3g/kg diet for 4 months. Outcomes were bone mineral density, bone biomechanics and markers of bone turnover. Bone mineral density of the femurs indicated that one of the whey AF over time caused a recovery of bone lost from OVX. Plasma C-telopeptide of type I collagen decreased significantly in all groups except OVX control over time, indicating an anti-resorptive effect of whey acidic protein. Biomechanical data showed that the AF may affect bone architecture as elasticity was increased by one of the whey AF. The femurs of AF-supplemented rats all showed an increase in organic matter. This is the first report of an acidic whey protein fraction isolated from milk whey that may support the recovery of bone loss in vivo.
Lactococcus lactisis capable of improving the riboflavin status in deficient rats
Authors: LeBlanc Jean Guy , Burgess Catherine , Sesma Fernando , de Giori Graciela Savoy , van Sinderen Douwe
Published: August 2005

Lactococcus lactisis a commonly used starter strain that can be converted from a vitamin B2consumer into a vitamin B2‘factory’ by over-expressing its riboflavin biosynthesis genes. The present study was conducted to assess in a rat bioassay the response of riboflavin produced by GM or native lactic acid bacteria (LAB). The riboflavin-producing strains were able to eliminate most physiological manifestations of ariboflavinosis such as stunted growth, elevated erythrocyte glutathione reductase activation coefficient values and hepatomegalia that were observed using a riboflavin depletion–repletion model. Riboflavin status and growth rates were greatly improved when the depleted rats were fed with cultures ofL. lactisthat overproduced this vitamin whereas the native strain did not show the same effect. The present study is the first animal trial with food containing living bacteria that were engineered to overproduce riboflavin. These results pave the way for analysing the effect of similar riboflavin-overproducing LAB in human trials.
Obesity induced during sexual maturation is linked to LDL-triacylglycerols in Yucatan miniature swine
Authors: Sébert Sylvain P. , Lecannu Gérard , Sené Sandrine , Hucteau Séverine , Chetiveaux Maud , Ouguerram Khadija , Champ Martine M.-J.
Published: August 2005

The incidence of childhood obesity is rising dramatically throughout industrialised countries. To evaluate and study the impact of childhood obesity on lipoprotein metabolism, we developed a new animal model of premature obesity. Yucatan mini-pigs aged 4 months were studied over a 12-month period from childhood to adulthood. Animals were divided into two groups: the first group were overfed a Western misbalanced diet; the second group were normally fed a recommended human-type diet. Cholesterol and triacylglycerol concentrations in VLDL-, LDL- and HDL-lipoproteins were followed from baseline to adulthood by fast protein liquid chromatography. At 10 (the end of sexual maturation) and 16 months old (adulthood), liver, visceral and subcutaneous adipose tissues were sampled. Real-time RT-PCR was performed in order to compare apo AI, apo B, apo C-III, PPAR-α, insulin receptor and lipoprotein lipase gene expression between groups and ages. Differences between groups were observed only after sexual maturity. Adult overfed mini-pigs had a higher LDL-cholesterol:HDL-cholesterol ratio (P<0·05; 0·55 (SE 0·06) for overfedv. 0·42 (SE 0·04) for normally fed pigs at the tenth month of the study). In both groups, VLDL-triacylglycerol decreased (P<0·05). VLDL-triacylglycerol evolution in the overfed group was associated with an increase in LDL-triacylglycerol plasma concentrations (P<0·05) after sexual maturation. LDL-triacylglycerol concentration in overfed mini-pigs went from an average of 0·28 mmol/l before sexual maturation to reach an average concentration of 0·56 mmol/l afterwards. This phenomenon has never been observed in similar studies when obesity is induced in adult mini-pigs and may represent a specific hallmark of an obesity induced during sexual maturity.
Prolonged feeding of difructose anhydride III increases strength and mineral concentrations of the femur in ovariectomized rats
Authors: Mitamura Rieko , Hara Hiroshi
Published: August 2005

This study demonstrates that feeding difructose anhydride III (DFAIII) improves bone strength and femoral mineral concentrations in a rat model of oestrogen deficiency. We showed the relationship between Ca, Mg and P absorption and bone characteristics in rats. Two groups of female Sprague-Dawley rats (6 weeks old) underwent bilateral ovariectomy (ovariectomized rats, OVX rats) or bilateral laparotomy (sham rats). At 10 weeks old, OVX and sham rats were divided into three subgroups and fed a control, 1·5 % DFAIII or 3 % DFAIII diet for 8 weeks, respectively. Ca but not Mg absorption rates were lowered by ovariectomy; however, ingestion of the 1·5 % and 3 % DFAIII diets similarly restored the reduced Ca absorption in OVX rats at 4 and 8 weeks after feeding of the test diets. DFAIII increased Mg absorption dose-dependently in sham and OVX rats. The bone strength, femoral Ca and Mg concentrations, and distal bone mineral density in the 3 % DFAIII group were higher than those in the control group in OVX rats. The absorption rates of Ca and Mg were significantly correlated with femoral Ca and Mg concentrations and strength, which suggests that increasing both Ca and Mg absorption improves bone characteristics in OVX rats. There were no differences in any of the variables in the femur between the 1·5 % and 3 % DFAIII groups in OVX rats. In conclusion, feeding of a low dose of DFAIII increased intestinal Ca and Mg absorption, and the promotive effect of DFAIII persisted for over 8 weeks. This effect was associated with prevention of ovariectomy-induced osteopenia.
A preliminary investigation of rider position during walk, trot and canter
Authors: Lovett Thomas , Hodson-Tole Emma , Nankervis Kathryn
Published: August 2005

The purpose of this study was to determine whether significant differences exist in the position of a horse rider when assessed at different points in the horse's stride cycle at walk, trot and canter on the right rein. Video analysis was used to determine the absolute angles of the trunk, thigh and lower leg of five subjects during the walk, rising trot and canter. The range of movement of the trunk, thigh and lower leg during each gait was also determined. At walk significant differences in the rider's trunk angle were found between limb impacts (P<0.05). At trot significant differences were found in all angles between impacts of the horse's diagonal limb pairs (P<0.05). At canter, there were no significant differences in rider position between limb impacts. The range of movement of the trunk was 5.9°, 4.1° and 4.7° for walk, trot and canter, respectively. The corresponding ranges of the thigh and lower leg were 1.9°, 7.3° and 4.4°, and 2.9°, 5.2° and 3.9°, respectively. This preliminary study has demonstrated differences in rider posture between limb impacts in walk and trot. Further work is necessary to investigate the forces acting on the rider during each gait and the postural strategies employed by riders to maintain a balanced position. Such work is a necessary forerunner to the study of rider influence on horse performance.
Changes in plasma cortisol and ascorbic acid in horses with and without recurrent airway obstruction upon exercise and ascorbic acid supplementation
Authors: Cuff TL , Williams RJ , Deaton CM , Smith NC , Davies BD , Davies-Morel MCG , Marlin DJ , Harris PA
Published: August 2005

Diminished basal plasma cortisol concentrations and a blunted cortisol response to exercise have been observed in human asthmatics. In horses with recurrent airway obstruction (RAO), plasma concentrations of cortisol at rest are not significantly different from those of healthy horses, but the effect of exercise on endogenous cortisol concentrations has not been described. Ascorbic acid is a non-enzymatic antioxidant with proposed immune-modulating properties. In man, supplementation with ascorbic acid has been shown to attenuate the exercise-induced increase in plasma cortisol following prolonged, submaximal exercise. The relationship between cortisol and ascorbic acid has not previously been investigated in the horse. In a blinded cross-over design, five horses with RAO and six healthy non-RAO controls performed a standard exercise test following 4 weeks of supplementation with either an antioxidant (providing 10 mg ascorbic acid kg−1day−1) or a placebo (<1 mg ascorbic acid kg−1day−1). Venous blood samples were obtained 1 h prior to exercise and at 0, 15, 60 min and 24 h thereafter. Exercise resulted in a significant increase in plasma cortisol concentrations in both groups of horses (P<0.05). Basal and post-exercise concentrations of plasma cortisol in the RAO group (136±16 and 210±16 μmol l−1, respectively) were not significantly different from those in the non-RAO group (129±43 and 218±30 μmol l−1, respectively). Antioxidant supplementation increased basal and post-exercise concentrations of plasma ascorbic acid in RAO and non-RAO horses (P<0.05) but had no effect on plasma cortisol concentration in either group, before or after exercise (RAO: rest 157±27 μmol l−1, post-exercise 222±21 μmol l−1; non-RAO: rest 140±11 μmol l−1, post-exercise 227±35 μmol l−1). In conclusion, RAO-affected horses in remission demonstrate the same cortisol response to exercise as healthy controls. Antioxidant supplementation had no impact on post-exercise concentrations of plasma cortisol in either healthy or RAO-affected horses in remission.
The influence of adrenaline on echocardiographic parameters of left ventricular function in the horse
Authors: Gehlen Heidrun , Marnette Silke , Stadler Peter
Published: August 2005

The purpose of the present study was to investigate the effect of adrenaline on cardiac function parameters. The infusion of adrenaline for induction of stress, its prospective side-effects as well as its effect on left ventricular function were investigated. A clinical examination and echocardiography were performed on 10 healthy horses before and after infusion of adrenaline. During a period of 6 min, infusion of 1 μg adrenaline kg−1min−1led to a significant increase in mean heart rate, from 36.5 to 55 beats min−1. Echocardiography during adrenaline infusion revealed a significant thickening of the interventricular septum (during systole) as well as a significant decrease in left ventricular diameter at the papillary muscle level (during both systole and diastole), and thus an increased contractility. The left ventricular area and the left ventricular volume were significantly decreased during adrenaline infusion, expressing the increased left ventricular contractility (during both systole and diastole). Other echocardiographic parameters of regional left ventricular function changed with only low-grade significance or without any significance at all. During and after infusion of adrenaline, the horses showed sweating, muscle tremor and other symptoms of discomfort. The study revealed that the increases in heart rate and myocardial contractility after infusion of adrenaline were low compared with changes observed during physical performance. Furthermore, severe adverse effects were observed. Taking into account the possible cardiotoxic effects of adrenaline, we do not consider this method appropriate for stress induction, particularly in horses with cardiac disorders.
Abnormal nuclear shape and impaired mechanotransduction in emerin-deficient cells
Authors: Lammerding Jan , Hsiao Janet , Schulze P. Christian , Kozlov Serguei , Stewart Colin L. , Lee Richard T.
Published: August 2005

Emery-Dreifuss muscular dystrophy can be caused by mutations in the nuclear envelope proteins lamin A/C and emerin. We recently demonstrated that A-type lamin-deficient cells have impaired nuclear mechanics and altered mechanotransduction, suggesting two potential disease mechanisms (Lammerding, J., P.C. Schulze, T. Takahashi, S. Kozlov, T. Sullivan, R.D. Kamm, C.L. Stewart, and R.T. Lee. 2004. J. Clin. Invest. 113:370–378). Here, we examined the function of emerin on nuclear mechanics and strain-induced signaling. Emerin-deficient mouse embryo fibroblasts have abnormal nuclear shape, but in contrast to A-type lamin-deficient cells, exhibit nuclear deformations comparable to wild-type cells in cellular strain experiments, and the integrity of emerin-deficient nuclear envelopes appeared normal in a nuclear microinjection assay. Interestingly, expression of mechanosensitive genes in response to mechanical strain was impaired in emerin-deficient cells, and prolonged mechanical stimulation increased apoptosis in emerin-deficient cells. Thus, emerin-deficient mouse embryo fibroblasts have apparently normal nuclear mechanics but impaired expression of mechanosensitive genes in response to strain, suggesting that emerin mutations may act through altered transcriptional regulation and not by increasing nuclear fragility.
OPUC on one foot
Authors: Simon Barry
Published: August 2005

We present an expository introduction to orthogonal polynomials on the unit circle (OPUC).
Complex symplectic spaces and boundary value problems
Authors: Everitt W. , Markus L.
Published: August 2005

This paper presents a review and summary of recent research on the boundary value problems for linear ordinary and partial differential equations, with special attention to the investigations of the current authors emphasizing the applications of complex symplectic spaces. In the first part of the previous century, Stone and von Neumann formulated the theory of self-adjoint extensions of symmetric linear operators on a Hilbert space; in this connection Stone developed the properties of self-adjoint differential operators generated by boundary value problems for linear ordinary differential equations. Later, in diverse papers, Glazman, Krein and Naimark introduced certain algebraic techniques for the treatment of appropriate generalized boundary conditions. During the past dozen years, in a number of monographs and memoirs, the current authors of this expository summary have developed an extensive algebraic structure, complex symplectic spaces, with applications to both ordinary and partial linear boundary value problems. As a consequence of the use of complex symplectic spaces, the results offer new insights into the theory and use of indefinite inner product spaces, particularly Krein spaces, from an algebraic viewpoint. For instance, detailed information is obtained concerning the separation and coupling of the boundary conditions at the endpoints of the intervals for ordinary differential operators (see the Balanced Intersection Principle), and the introduction of the generalized boundary conditions over the region for some elliptic partial differential operators (see the Harmonic operator).
A Cautionary Tale
Authors: Gorog Diana A , Russell Georgina , Casian Alina , Peters Nicholas S
Published: August 2005

Myotonic dystrophy (MD) is associated with important cardiac abnormalities, and 30% of deaths are attributable to cardiac causes, predominantly arrhythmias. Sodium channel blockers have been used to improve muscle strength and relaxation in MD. Flecainide is a potent selective blocker of the mutant sodium channel in myotonia and inhibits the abnormal noninactivating sodium current in both painful myotonia congenita and painless MD with a resultant improvement in muscle relaxation. We describe the case of a 41-year-old woman with MD who developed ventricular tachycardia (VT) while taking flecainide to improve her muscle strength. Flecainide was discontinued and VT could not subsequently be induced. Although flecainide is an effective antiarrhythmic agent, it may also be proarrhythmic, particularly in patients at risk for VT. We recommend careful cardiac assessment, risk stratification, and consideration of high-risk patients for early screening electrophysiological studies, especially if considering use of a class 1 antiarrhythmic agent.
Primary Lateral Sclerosis
Authors: Singer Mike A , Kojan Suleiman , Barohn Richard J , Herbelin Laura , Nations Sharon P , Trivedi Jaya R , Jackson Carlayne E , Burns Dennis K , Boyer Philip J , Wolfe Gil I
Published: August 2005

Objective:

The objective of this study was to characterize the clinical features and natural history of primary lateral sclerosis (PLS).

Background:

PLS is a motor neuron disorder defined by corticospinal and corticobulbar tract dysfunction without clinically significant lower motor neuron involvement.

Methods:

We collected data from 25 patients with PLS seen in 2 academic neurology departments over a 5-year period.

Results:

The PLS population represented approximately 3% of acquired motor neuron disease cases seen during that period. Twenty-three patients (92%) presented with lower limb weakness, spasticity, or difficulty with ambulation. None presented with upper limb symptoms. Eleven patients (44%) developed bulbar symptoms. All patients had hyperreflexia and increased muscle tone. Muscle weakness was observed in 15 patients (60%) and tended to be mild and asymmetric. Needle electromyography (EMG) was normal or showed only fasciculations in 15 patients (60%); 10 patients had features of mild active denervation, consisting of fibrillation or positive sharp wave potentials, but the extent of these findings did not satisfy World Federation of Neurology electrophysiological criteria for the diagnosis of amyotrophic lateral sclerosis. Fourteen patients (52%) continued independent ambulation. Of the 10 patients with active denervation on EMG, 6 (60%) required a walker, scooter, or wheelchair at a mean follow up of 6.2 years. There were no fatalities over the 5-year period.

Conclusions:

Our experience supports the observation that PLS progresses more slowly than other forms of acquired motor neuron disease, particularly amyotrophic lateral sclerosis. Follow-up data suggest that patients with active denervation changes develop greater disability.
Perindopril Regulates β-Agonist-Induced Cardiac Apoptosis
Authors: Gálvez Anita S , Fiedler Jenny L , Ocaranza María Paz , Jalil Jorge E , Lavandero Sergio , Díaz-Araya Guillermo
Published: August 2005

Administration of the β-adrenergic agonist isoproterenol results in cardiac apoptosis. The effect of short-term β-adrenergic stimulation by isoproterenol on the activity of plasma, lung, and left ventricular (LV) angiotensin I-converting enzyme (ACE) activity and its association with the development of cardiac apoptosis was investigated. β-Adrenergic stimulation for 24 hours produced an early increase only in the proapoptotic proteins bax and bcl-XS without changes in the levels of the antiapoptotic protein bcl-XL. The ratio between these bcl family proteins was indicative of apoptosis and correlated with an early and significant increase (300%) in DNA laddering. However, after 5 days of the β-adrenergic stimulation, the ratio changed in favor of antiapoptotic proteins and correlated with the absence of DNA fragmentation. In addition, LV and plasma ACE activities increased markedly with isoproterenol over the study period up to 5 days. ACE activity also regulated expression of the antiapoptotic gene bcl
-XL. The administration of perindopril (an ACE inhibitor) prevented the observed increase in bax and bcl-XS levels and attenuated (50% decrease, P < 0.05) the effect of isoproterenol on DNA fragmentation. Thus, early and transient cardiac apoptosis triggered by the β-adrenergic agonist isoproterenol is reversed in the presence of perindopril.
Antihypertensive and Endothelium-Dependent Vasodilator Effects of Alpinia zerumbet, a Medicinal Plant
Authors: de Moura R Soares , Emiliano A F , de Carvalho L C. R. Marins , Souza M A. V , Guedes D C , Tano T , Resende A C
Published: August 2005

Alpinia zerumbet (K. Schum), a medicinal plant originated from West Asia, is used in the northeast and southeast of Brazil as infusions or decoctions as a diuretic, antihypertensive, and antiulcerogenic. Experiments were undertaken to determine whether a hydroalcoholic extract obtained from leaves of Alpinia zerumbet (AZE) induces vasodilation in the mesenteric vascular bed (MVB), and an antihypertensive effect was also assessed in rats with DOCA-salt hypertension. In MVB precontracted with norepinephrine, AZE induces a long-lasting endothelium-dependent vasodilation that is not reduced by indomethacin. Inhibition of NO synthase by NG-nitro-L-arginine methyl ester (L-NAME) and guanylyl cyclase by 1H-[1,2,3]oxadiazolo [4,4-a]quinoxalin-1-one (ODQ) reduces the vasodilator effect of AZE. In vessels precontracted with norepinephrine, the vasodilator effect of AZE was not changed by 4-aminopyridine, glibenclamide, or by charybdotoxin plus apamin. Concentrations of atropine, pyrilamine, and yohimbine that significantly reduced the vasodilator effect of acetylcholine, histamine, and clonidine, respectively, did not change the vasodilator effect of AZE. HOE 140, which significantly reduced the vasodilator effect of bradykinin, induced a slight but significant reduction on the vasodilator effect of AZE. Chronic oral administration of AZE induced a significant reduction in systolic, mean, and diastolic arterial pressure in rats with DOCA-salt hypertension. Probably the vasodilator effect of AZE is dependent on the activation of the NO-cGMP pathway and independent of activation of ATP-dependent, voltage-dependent, and calcium-dependent K+ channels. Bradykinin receptors may also participate in the vasodilator effect of AZE. Finally, the vasodilator and antihypertensive effects of AZE demonstrated in the present study provide experimental support for the indication of Alpinia zerumbet as an antihypertensive medicinal plant.
Effect of Acetylsalicylic Acid on Nuclear Factor-κB Activation and on Late Preconditioning Against Infarction in the Myocardium
Authors: Jancso Gabor , Cserepes Barbara , Gasz Balázs , Benkő Laszlo , Ferencz Andrea , Borsiczky Balazs , Lantos Janos , Dureja Anjali , Kiss Katalin , Szeberényi Jozsef , Rőth Elizabeth
Published: August 2005

Nuclear factor-κB (NF-κB) plays an essential role in the intracellular signal transduction of the second window of protection (SWOP). Acetylsalicylic acid (ASA) blocks NF-κB-dependent gene activation in leukocytes and endothelial cells through preventing phosphorylation and subsequent degradation of the inhibitor IκB-α. This study investigated the effect of ASA on the late phase of ischemic preconditioning (PC) against myocardial infarction and on the activation of NF-κB in the preconditioned myocardium. Conscious rabbits were subjected to 4 cycles of 5 minutes of coronary occlusion and 5 minutes of reperfusion together with 3 different doses of ASA (5 mg/kg; 25 mg/kg; 130 mg/kg). After 30 minutes of reperfusion we determined the activation of NF-κB with an electrophoretic mobility shift assay (EMSA). Twenty-four hours later, after 30 minutes of test ischemia, we performed infarct size analysis using triphenyltetrazolium-chloride (TTC) staining. Neither 5 mg/kg (antithrombotic dose) nor 25 mg/kg (analgesic/antipyretic dose) of ASA interfered with the NF-κB activation and the protective effect of late preconditioning against myocardial infarction. In contrast, NF-kB activation and late PC effect were completely abrogated by 130 mg/kg of ASA. Our results suggest that nonselective doses of NSAIDs should be used with caution in patients with atherosclerotic cardiovascular disease because they may deprive the heart of its innate defensive response.
2-Bromoethylamine, a Suicide Inhibitor of Semicarbazide-Sensitive Amine Oxidase, Increases Hydralazine Hypotension in Rats
Authors: Vidrio Horacio , Medina Martha
Published: August 2005

Previous work has shown that inhibitors of the predominantly vascular enzyme semicarbazide-sensitive amine oxidase (SSAO) potentiate the hypotensive response to hydralazine, itself a SSAO inhibitor, in anesthetized rats. The present study was carried out to determine whether the recently described suicide SSAO inhibitor 2-bromoethylamine shares this effect. Hypotensive responses to hydralazine, 0.1 mg/kg IV, were obtained in chloralose-urethane-anesthetized rats, either unpretreated or receiving bromoethylamine at different doses and pretreatment intervals. Parallel experiments were run with semicarbazide, the prototypical hydrazine SSAO inhibitor. Both inhibitors potentiated hydralazine hypotension, bromoethylamine having a longer latency and a shorter duration of action than semicarbazide. High doses of bromoethylamine did not produce potentiation, a phenomenon attributed to SSAO inactivation by excess substrate and decreased formation by the enzyme of the inhibitor product. Experiments with combined administration of both inhibitors were also carried out. When semicarbazide was administered before bromoethylamine, potentiaton was prevented, apparently by a mechanism similar to the above; when it was given after the amine, potentiation was increased. This was attributed to enzyme inhibition by interaction with 2 different active sites. The charactertistics of hydralazine potentiation by bromoethylamine were considered compatible with the mechanism of SSAO inhibition by the amine.
Dehydroepiandrosterone Sulfate Induces Acute Vasodilation of Porcine Coronary Arteries In Vitro and In Vivo
Authors: Hutchison Stuart J , Browne Amanda E M , Ko Eitetsu , Chou Tony M , Zellner Christian , Komesaroff Paul A , Chatterjee Kanu , Sudhir Krishnankutty
Published: August 2005

Although an inverse relationship between dehydroepiandrosterone sulfate (DHEAS) and coronary artery disease has been demonstrated in men, the vascular effects of DHEAS are not well defined. The vasoactive effects of intracoronary DHEAS and testosterone (0.1 nM to 1 μM) were examined in vivo in 24 pigs. Epicardial cross-sectional area was measured by intravascular ultrasound, and coronary flow velocity by intravascular Doppler velocimetry. We also examined the effects of antagonism of the androgen receptor, nitric oxide synthase, and potassium channels on DHEAS-induced vasodilation in vitro in coronary rings from male and female pig hearts. DHEAS and testosterone induced increases in cross-sectional area, average peak velocity, and coronary blood flow. The maximal increase in coronary blood flow in response to testosterone was 1.26-fold (P= 0.02), and in average peak velocity 1.43-fold (P= 0.05), greater than that to DHEAS, whereas increases in cross-sectional area were similar. Vasodilation to both hormones was rapid, with maximal responses occurring <10 minutes after administration. In vitro, DHEAS and testosterone induced vasodilation in coronary rings, greater with testosterone. At doses of 0.1 and 1 μM, the vasodilator effects of DHEAS and testosterone were inhibited by the androgen receptor antagonist flutamide but not the estrogen receptor antagonist ICI 182,780. At 10 μM, neither DHEAS- nor testosterone-induced vasorelaxation was inhibited by flutamide, ICI 182,780, L-NAME, or deendothelialization, but both were attenuated by pretreatment with glibenclamide. No gender differences were observed in any of the responses examined. In conclusion, DHEAS is an acute coronary artery vasodilator, but less potent than testosterone. Its effect might be mediated via androgen receptors and may involve ATP-sensitive potassium channels.
Effect of cassava fluid on corrosion performance of mild steel
Authors: Jekayinfa S.O. , Waheed M.A. , Adebiyi K.A. , Adebiyi F.T.
Published: August 2005

Purpose

The cheapest and most rapidly available metal for agro‐processing equipment fabrication in Nigeria is plain carbon steel. However, there are some aggressive ions present in raw agricultural and food products, which may attack the steel components of these processing machinery, resulting in their untimely failure in service. The present study investigates the effect of fluid squeezed from cassava tuber on the corrosion behaviour of mild steel.

Design/methodology/approach

The investigation involved periodic weight loss measurements of 0.8 per cent carbon and 0.36 per cent carbon steel rods as they were exposed to cassava fluid. The relationships between loss in weight of the exposed samples and exposure period were determined. Models were developed to relate corrosion rate in each environment with total surface area and exposure period.

Findings

The results show that 0.36 per cent carbon steel was less affected by corrosion than 0.18 per cent carbon steel, with corrosion intensity in both cases, increasing with duration of immersion. Generally, there was low level of corrosion resistance (high corrosion rate) by the two steel materials. The correlation coefficient between the experimental values of corrosion rates and predicted values (using the developed models) was high.

Originality/value

In food and agricultural industries, product quality, health and sanitation issues are the major concerns. The industries cannot tolerate corrosion deposits in the manufactured products. Hence, material selection for machinery fabrication is essential. In line with this, the results of this study indicate that mild steel materials are unsuitable for use in cassava processing without some forms of surface treatment.