bluuebunny/crossref_metadata_2025 huggingface dataset:
Photodamage to Pigment in the Photosystem II Reaction Center D1/D2/Cytochrome b559 Complex
Authors: Liu Shuang , Dong Feng‐Qin , Tang Chong‐Qin , Kuang Ting‐Yun , Li Liang‐Bi , Liu Yu‐Long
Published: July 2006

Strong light (800 μmol photons/m2 per s)‐induced bleaching of the pigment in the isolated photosystem II reaction center (PSII RC) under aerobic conditions (in the absence of electron donors or acceptors) was studied using high‐pressure liquid chromatography (HPLC), absorption spectra, 77K fluorescence spectra and resonance Raman spectra. Changes in pigment composition of the PSII RC as determined by HPLC after light treatment were as follows: with increasing illumination time chlorophyll (Chl) a and β‐carotene (β‐car) content decreased. However, decreases in pheophytin (Pheo) could not be observed because of the mixture of the Pheo formed by degraded chlorophyll possibly. On the basis of absorption spectra, it was determined that, with a short time of illumination, the initial bleaching occurred maximally at 680 nm but that with increasing illumination time there was a blue shift to 678 nm. It was suggested that P680 was destroyed initially, followed by the accessory chlorophyll. The activity of P680 was almost lost after 10 min light treatment. Moreover, the bleaching of Pheo and β‐car was observed at the beginning of illumination. After illumination, the fluorescence emission intensity changed and the fluorescence maximum blue shifted, showing that energy transfer was disturbed. Resonance Raman spectra of the PSII RC excited at 488.0 and 514.5 nm showed four main bands, peaking at 1 527 cm‐1 (v1), 1 159 cm‐1 (v2), 1 006 cm‐1 (v3), 966 cm‐1 (v4) for 488.0 nm excitation and 1 525 cm‐1 (v1), 1 159 cm‐1 (v2), 1 007 cm‐1 (v3), 968 cm‐1 (v4) for 514.5 nm excitation. It was confirmed that two spectroscopically different β‐car molecules exist in the PSII RC. After light treatment for 20 min, band positions and bandwidths were unchanged. This indicates that carotenoid configuration is not the parameter that regulates photoprotection in the PSII RC.

(Managing editor: Ping He)
Climatic Control on Forests and Tree Species Distribution in the Forest Region of Northeast China
Authors: Wang Xiang‐Ping , Tang Zhi‐Yao , Fang Jing‐Yun
Published: July 2006

North‐east (NE) China covers considerable climatic gradients and all major forests types of NE Asia. In the present study, 10 major forest types across the forest region of NE China were sampled to investigate forest distribution in relation to climate. Canonical correspondence analysis (CCA) revealed that growing season precipitation and energy availability were primary climatic factors for the overall forest pattern of NE China, accounting for 66% of the explanatory power of CCA. Conversely, annual precipitation and winter coldness had minor effects. Generalized additive models revealed that tree species responded to climatic gradients differently and showed three types of response curve: (i) monotonous decline; (ii) monotonous increase; and (iii) a unimodal pattern. Furthermore, tree species showed remarkable differences in limiting climatic factors for their distribution. The power of climate in explaining species distribution declined significantly with decreasing species dominance, suggesting that the distribution of dominant species was primarily controlled by climate, whereas that of subordinate species was more affected by competition from other species.

(Managing editor: Ya‐Qin Han)
Variation of Soil Nutrition in a Fagus engleriana Seem.‐ Cyclobalanopsis oxyodon Oerst. Community Over a Small Scale in the Shennongjia Area, China
Authors: Zhang Mi , Xie Zong‐Qiang , Xiong Gao‐Ming , Zhang Jin‐Tun
Published: July 2006

Soil nutrition is a key factor influencing species composition in a community, but it has clearly scale‐dependent heterogeneity. In the present study, geostatistics methods and canonical correspondence analysis (CCA) were used to detect: (i) the variation range of soil spatial heterogeneity; (ii) the influence of topographic factors on the distribution of soil nutrition; and (iii) the relationships between soil chemical properties and species in the community. In all, 23 soil variables were measured, including total N and organic C, Al, Ba, Ca, Cr, Cu, Fe, Ga, Li, Mg, Mn, Na, NH4‐N, Ni, NO3‐N, Pb, pH, P, Sr, Ti, V, and Zn. Semi‐variograms of these variables were calculated and mapped. All indices showed autocorrelations, with ranges between 29 and 200 m. When the sample method was larger than these distances, spatial autocorrelations were avoided. The distribution patterns of Ca, Cr, Ga, K, Mg, organic C, P, Pb, and pH, and total N were related to the microtopography and the distribution of these compounds was clumped in water catchments area. The CCA method was used to investigate the relationship between plant species and soil properties in this community. Fagus engleriana Seem., Lindera obtusiloba Bl. Mus., and Acer griseum (Franch.) Pax were correlated with organic C, available N, and P.

(Managing editor: Ya‐Qin Han)
Effect of Osmotic Stress in Early Stages of Ontogenesis on Root Respiration, Growth, Sugar Content, and Cell Injury in Maize Seedlings Differing in Drought Sensitivity
Authors: Kolarovič Lukáš , Luxová Miroslava , Valentovič Peter
Published: July 2006

Cultivars of maize (Zea mays L.) with different sensitivity to drought were exposed to 0.3 mol/L sorbitol (‐1.4 MPa water potential) for 24 h. Exposure to water deficiency significantly reduced the growth of both shoots (coleoptile and hypocotyl) and roots. Shoot growth was inhibited more than the growth of roots. Osmotic stress enhanced accumulation of soluble sugars. Electrolyte leakage, a cell injury index, was slightly increased after 0.3 mol/L sorbitol. Respiration was measured in the presence and absence of 2,6‐dichlorophenol indophenol. 2, 6‐Dichlorophenol indophenol did not influence respiration rates, because statistically equal results were observed under both conditions. Total respiration (vT) decreased after osmoticum treatment. There were no significant differences in the vT among the cultivars analysed. The decrease in vT was caused by a decline in the activities and capacities of both cytochrome (vcyt, Vcyt) and alternative pathway (valt, Valt) of respiration. A high residual respiration (vres) was observed, up to 27% of total uninhibited respiration. The result of uncoupler use clearly indicated that coupling was maintained after 24 h of osmotic stress. The recovery of the respiration rate was comparable with that of non‐stressed control rates. According to these observations, no possible mitochondrial damage is expected. Water deficiency did not induce a stimulation of the alternative oxidase, so we assume that the stimulation of the alternative pathway is not related to drought stress resistance; rather, the function of the alternative pathway is to balance carbon metabolism and electron transport in a response to a changing environment.

(Managing editor: Ping He)
Hierarchical Strategy for Identifying Active Chemotype Classes in Compound Databases
Authors: Medina‐Franco José Luis , Petit Joachim , Maggiora Gerald M.
Published: July 2006

A general methodology is presented for analyzing patterns of activity in compound databases, which is based on the use of structural chemotypes and provides a focused, hierarchical classification of active compounds. Each node in the hierarchical tree corresponds to a specific chemotype and is labeled by a unique code or identifier. All chemotypes at a given level of the hierarchy define equivalence classes, and those of higher structural resolution have a strict parent–child (i.e. subset) relationship to those of lower resolution. Active chemotypes contain a relatively high proportion of actives and are characterized through the use of enrichment plots. These plots show the relationship of occupancy to activity enrichment for a set of chemotypes at a given level of structural resolution. Paths through the hierarchy from chemotypes of lower to those of higher structural resolution (e.g. reduced cyclic system skeletons → cyclic system skeletons → cyclic systems → complete molecules) are unique. Unique paths in the hierarchy that only pass through active chemotypes are called chains or paths of actives. These chains provide links for identifying structurally related active compounds at increasing levels of structural resolution. Analysis of actives can also be carried out at any specific level of structural resolution deemed appropriate by the investigator. Chemotype codes can be used to search compound databases for new molecules possessing these codes or sets of hierarchically related codes. An example, based on the NCI AIDS database, is presented that illustrates the general approach and provides a more detailed description of several interesting classes of active chemotypes and their inter‐relationships.
Synthesis and Pharmacological Activity of 2‐(substituted)‐3‐{2‐[(4‐phenyl‐4‐cyano)piperidino]ethyl}‐1,3‐thiazolidin‐4‐ones
Authors: Mazzoni Orazio , Di Bosco Antonio Mazzella , Grieco Paolo , Novellino Ettore , Bertamino Alessia , Borrelli Francesca , Capasso Raffaele , Diurno Maria Vittoria
Published: July 2006

Loperamide is a well‐known peripherally acting opiate used for the treatment of diarrhoea. To gain more knowledge on the structure–activity relationships of antidiarrhoeal drugs and to develop new active molecules, a series of aryl‐cyano‐piperidinoalkyl‐thiazolidinones related to Loperamide was synthesized and screened for antidiarrhoeal activity in mice by castor oil test. To characterize the potency and toxicity of the synthesized compounds ED50 and LD50 values were also determined. The thiazolidinones 2–6 displayed antidiarrhoeal activity at doses ranging between 15 and 82 mg/kg. Although the results show that the synthesized compounds are 15‐ to 80‐fold less active respect to the reference compound, Loperamide, they are much less toxic (≥1000 mg/kg and 108.9 mg/kg, respectively). Besides, to evaluate the involvement of opioid receptors in antidiarrhoeal activity, Naloxone was administered prior to test the 2‐phenyl‐3‐{2‐[(4‐phenyl‐4‐cyano)piperidino]ethyl}‐1,3‐thiazolidin‐4‐one (2), the more active compound of this series. The results obtained by this study, suggest that the antidiarrhoeal activity of this series of thiazolidinone derivatives could involve the opioid receptors.
Plasticization of Pea Starch Films with Monosaccharides and Polyols
Authors: Zhang Yachuan , Han J. H.
Published: July 2006

ABSTRACT:  Monosaccharides have several hydroxyl groups and a compatible structure with starch polymers resulting in effective plasticization in starch films. Two groups of plasticizers (polyols and monosaccharides) were used to compare their plasticizing efficiency. Fructose, glucose, mannose, galactose, glycerol, sorbitol, ethylene glycol, and maltitol were selected at 13.031 mmol per 100 g of pea starch. Edible starch films were produced after heat gelatinization and dehydration of the 3% starch dispersion. The microstructure, attenuated total reflection foorier transform infrared (ATR‐FTIR) characteristics, thickness, moisture content, tensile strength, modulus of elasticity, elongation‐at‐break, water vapor permeability, and transparency of films were determined. Microstructure of the film solutions showed that some swollen starch granules and their remnants existed in the film. Compared to the FTIR spectra of pure starch films, the spectra of plasticized films showed that more hydrogens bound hydroxyl groups and more water molecules were attracted around starch polymer chains. Ethers were produced in glycerol‐plasticized films. Monosaccharide‐plasticized films were comparable to the polyol‐plasticized films in tensile test, but more resistant in moisture permeation than the polyol‐plasticized films. It was assumed that the structural compatibility of monosaccharides with starch might result in denser polymer‐plasticizer complex, smaller size of free volume, and less segmental motions of starch chains. In conclusion, monosaccharides were identified as effective plasticizers for starch film.
Chemical Characterization of Liver Lipid and Protein from Cold‐Water Fish Species
Authors: Bechtel Peter J. , Oliveira Alexandra C.M.
Published: July 2006

ABSTRACT:  The largest US harvests of marine fish for human consumption are from Alaska waters. Livers from these fish are combined with other fish offal and made into fish meal and oil or discarded. The purpose of this study was to characterize liver lipids and proteins from important commercial species including walleye pollock (WP), pink salmon (PS), Pacific halibut (PH), flat head sole (FS), and spiny head rock fish (RF), and underutilized species including arrow tooth flounder (AF) and big mouth sculpin (BS). Liver lipid content ranged from 50.3% in WP to 3.3% in PS. Protein content ranged from 7.7% in WP to 18.4% in BS. PS livers had the highest content of ω‐3 fatty acids at 336 mg/g of oil and AF had the lowest content at 110 mg/g of oil. There were significant differences in the content of 9 amino acids with methionine and lysine values ranging from 2.66% to 3.43% and 7.19% to 9.45% of the total amino acids, respectively. Protein from the cold water marine fish livers was of high quality and the oils contained substantial quantities of ω‐3 fatty acids. Fish livers had distinct chemical properties and can be used for the development of unique food ingredients.
Effects of Whey Permeate‐Based Medium on the Proximate Composition of Lentinus edodes in the Submerged Culture
Authors: Wu Xiaojun Jeffrey , Hansen Conly
Published: July 2006

ABSTRACT:  Biomass production, crude water‐soluble polysaccharide (WSP), ash content, mineral profile, and crude protein content were determined for Lentinus edodes mycelia grown on whey permeate (WP)‐based medium with lactose content of 4.5% or defined synthetic medium, and harvested after 5, 10, 15, or 20 d of fermentation at 25 °C. Harvesting time and the type of media interact to alter the chemical content of mycelia. Mycelia grown in WP had greater (P < 0.05) WSP and ash than mycelia grown in the synthetic media. A maximum production of WSP was obtained on the 10th day (4.1 × 102± 71 mg WSP/g dried mycelia) from mycelia grown on the WP‐based media. Mycelia grown on WP harvested on the 20th day had the highest value in ash content (18 ± 3%). Potassium was found to be the main constituent in the ash of mushroom mycelia, which was followed by phosphorus, sodium, calcium, and magnesium. A steady increase of ash content was only noted in mycelia grown on WP. The calcium content of WP‐grown mycelia was at least 10 times higher compared to mycelia grown in the control media regardless the harvesting time. Data in this research suggested that WP was more favorable than the synthetic media in the production of WSP, which is traditionally known for their medicinal value in L. edodes.
Lutein Is Stable in Strawberry Yogurt and Does Not Affect its Characteristics
Authors: Aryana Kayanush J. , Barnes Hannah T. , Emmick Tatia K. , McGrew Paula , Moser Barry
Published: July 2006

ABSTRACT:  The impact of various levels of lutein on the physicochemical, microbiological, and sensory characteristics of yogurt over its shelf life was determined. Nonfat strawberry yogurts were prepared with 0, 0.5, 1.5, and 3.0 mg lutein per 170 g serving (20% overages were included to account for processing losses). The lutein was incorporated prior to homogenization of the yogurt mix. Stability of lutein, viscosity, pH, syneresis, standard plate counts, coliform counts, color (L*, a*, b*), and sensory evaluation (flavor, body and texture, and appearance and color) were measured at weeks 0, 1, 3, and 5 after product manufacture. The interaction effect between levels of lutein and storage time was significant for a* (redness‐greenness) values. Lutein levels remained above target throughout the 5‐wk storage study. Lutein did not affect viscosity, pH, syneresis, L* (lightness) and b* (yellowness‐blueness) values, standard plate counts, coliform counts, flavor, body, texture, appearance, and color scores. These results suggested that lutein was suitable for inclusion in functional yogurts. The skin and eye health benefits provided by lutein can easily be incorporated into yogurt to complement inherent nutritional properties.
1‐Methylcyclopropene Counteracts Ethylene‐Induced Microbial Growth on Fresh‐Cut Watermelon
Authors: Zhou Bin , McEvoy James L. , Luo Yaguang , Saftner Robert A. , Feng Hao , Beltran Tony
Published: July 2006

ABSTRACT:  The effects of exogenous ethylene, 1‐methylcyclopropene (1‐MCP), or both on microbial growth on watermelon fruit and watermelon slices were investigated. Freshly harvested seedless watermelons (Citrullus lanatus, cv. Sugar Heart) were treated with 0.5 or 1.0 ppm 1‐MCP, 10 ppm ethylene, 1‐MCP + ethylene, or left untreated as controls. Fruits were processed into wedge‐shaped slices, packaged into rigid trays sealed with a polyethylene film with a 29.2 pmol s−1 m−2 Pa−1 oxygen transmission rate. The slices were evaluated after 0‐, 6‐, and 12‐d storage at 5 °C. Ethylene treatment alone increased the populations of aerobic bacteria, lactic acid bacteria, and yeasts and molds on the packaged slices during storage compared to those on corresponding control slices and resulted in extensive juice leakage from the slices. The ethylene treatment also resulted in high aerobic bacterial counts throughout the flesh of whole melons compared to the controls. Treating watermelons with 0.5 or 1.0 ppm 1‐MCP prior to ethylene exposure counteracted the deleterious effects of ethylene. Extending the time from harvest to 1‐MCP treatment increased the population of aerobic bacteria, but had no detectable effect on the growth of lactic acid bacteria or yeasts and molds. The results indicate that low concentrations (0.5 or 1.0 ppm) of 1‐MCP can be used on whole watermelon to avoid deleterious effects of exogenous ethylene to which the melons could be exposed during shipping or storage.
Phycoerythrin Contributes to the Photooxidation of Eicosapentaenoic Acid in Porphyra yezoensis During Light Exposure
Authors: Sugawara Tatsuya , Komura Yukako , Hagino Hiroshi , Hirata Takashi
Published: July 2006

ABSTRACT:  Porphyra yezoensis, a red alga, is widely consumed as a familiar daily food in Japan. Lipid oxidation products including volatile decompositions during drying process might contribute to the quality and flavor of dried nori prepared from P. yezoensis. To explore the mechanism of photooxidation in the alga during light exposure, we investigated the contribution of phycoerythrin to eicosapentaenoic acid (EPA) photooxidation in P. yezoensis. After EPA dispersed in aqueous solution in the presence of Tween 20 was incubated with phycoerythrin under light‐exposed condition, the 6‐ and 17‐isomers of methyl trimethylsiloxy eicosanoate derived from 6‐ and 17‐hydroperoxy EPA, respectively, the specific hydroperoxide isomers by photosensitized oxidation, were detected by gas chromatography–mass spectrometry analysis. After the light exposure for 15 h at 4 °C, the generation of 6‐hydroperoxy EPA in P. yezoensis was 2 times higher than in a fresh alga. Moreover, 17‐isomer production by light exposure was almost 14 times higher than in nontreated control. After exposing to filtered light passed through a band‐pass‐type filter that can transmit 60% of light of maximum wavelength at 550 nm for partial excitation of phycoerythrin, each amount of 6‐ and 17‐isomer (approximately 80% and 25% of that exposed by nonfiltered light) was higher than in a fresh alga. These results suggested that phycoerythrin might, at least in part, contribute to the generation of singlet oxygen and the photooxidation of lipid in P. yezoensis during light exposure. The content of phycoerythrin would be important for the quality of color, flavor, nutrition, and biological functions in P. yezoensis.
A Continuous High‐Pressure Carbon Dioxide System for Cloud and Quality Retention in Orange Juice
Authors: Kincal D. , Hill W.S. , Balaban M. , Portier K.M. , Sims C.A. , Wei C.I. , Marshall M.R.
Published: July 2006

ABSTRACT:  Orange juice (OJ) was treated with a continuous high‐pressure carbon dioxide (HPCD) system, and the quality parameters pH, Brix, titratable acidity (TA), cloud, pectinesterase (PE) activity, color, and sensory attributes were determined. Treatment pressures were 38, 72, and 107 MPa, and CO2/juice (w/w) ratios were from 0.40 to 1.18. Residence time was kept at 10 min. Cloud increased between 446% and 846% after treatments. There were no significant changes in pH and Brix (α= 0.05). TA of the treated juice was found to be significantly different from that of control (α= 0.01). PE was not completely inactivated. There was a small, but significant increase in juice L‐value (α= 0.01) and a decrease in a‐value for color. There was no significant change in b‐values (α= 0.05). Statistical analysis for the sensory data showed no difference between fresh, frozen control juice and treated juice after 2 wk of refrigerated storage at 1.7 °C.
The Paradox of Toughening During the Aging of Tender Steaks
Authors: Novakofski Jan , Brewer Susan
Published: July 2006

ABSTRACT:  Aging is the practice of holding meat at low temperatures to improve tenderness that is the most important sensory attribute affecting consumer acceptability of beef. Because of the inconsistencies in measured tenderness changes during aging, we attempted to look at the relationship between aging and initial tenderness irrespective of animal age, genetics, or nutritional status. Cattle were selected to represent a full range of quality grades from Utility to Prime. Steaks from these cattle were aged in vacuum bags for 0, 7, or 14 d and tenderness characteristics were assessed. Steaks were cut from the frozen loin sections, thawed, and cooked on open hearth grills to 70 °C. Sensory evaluation was completed by a 6‐member trained sensory evaluation panel and Warner‐Bratzler shear was determined. The average shear values decreased with aging time across most grade categories; however, improvement was not uniform. Steaks from Utility grade cattle improved the most while steaks of other grades improved less. Shear values overlapped a great deal across all grades and to gain a better understanding of changes with aging, steaks were grouped based on initial shear value differences of 1 kg. Shear value of the toughest steaks decreased the most during aging (−36%), while those with the lowest shear values increased (16%). The same pattern emerged when steaks were grouped by initial tenderness. These results suggest that initially tough steaks will benefit from aging while very tender steaks may be adversely affected.
HPLC Analysis of Catechins, Theaflavins, and Alkaloids in Commercial Teas and Green Tea Dietary Supplements: Comparison of Water and 80% Ethanol/Water Extracts
Authors: Friedman Mendel , Levin Carol E. , Choi Suk‐Hyun , Kozukue Etsuko , Kozukue Nobuyuki
Published: July 2006

ABSTRACT:  To help meet the needs of consumers, producers of dietary tea supplements, and researchers for information on health‐promoting tea compounds, we compared the following conditions for the extraction of tea leaves and green tea‐containing dietary supplements: 80% ethanol/water at 60 °C for 15 min and boiled water for 5 min. The following 7 catechins, 4 theaflavins, and 3 alkaloids were separated in a 70‐min single HPLC analysis: (−)‐epigallocatechin, (−)‐catechin, (+)‐epicatechin, (−)‐epigallocatechin‐3‐gallate, (−)–gallocatechin‐3‐gallate, (−)‐epicatechin‐3‐gallate, (−)‐catechin‐3‐gallate, theaflavin, theaflavin‐3‐gallate, theaflavin‐3′‐gallate, theaflavin‐3,3′‐digallate, caffeine, theobromine, and theophylline. The following ranges of concentrations of flavonoids (catechins plus theaflavins) in the tea leaves extracted with 80% ethanol were observed (in mg/g): in 32 black teas, 19.8 to 115.1; in 24 green teas, 12.3 to 136.3; in 14 specialty teas, 4.9 to 118.5; in 7 herbal teas, 0 to 46.0. Total alkaloids in all teas ranged from 0 to 32.6 mg/g. Significantly greater amounts of flavonoids were extracted from the tea leaves with aqueous ethanol than with boiled water. Levels of tea catechins in 10 capsules sold as dietary supplements were about 50 to 75% lower than the amounts listed on the labels. Catechin content of 4 commercial green tea extracts ranged from 96 to 696 mg/g. The results make it possible to maximize the extraction of tea compounds to better relate the flavonoid and alkaloid content of teas and dietary tea supplements to their health‐promoting effects.
Antiyeast Potency of Heated Garlic in Relation to the Content of Allyl Alcohol Thermally Generated from Alliin
Authors: Kim Jay Wook , Choi Jong Hoon , Kim Youn‐Soon , Kyung Kyu Hang
Published: July 2006

ABSTRACT:  The appearance of antiyeast activity in heated garlic extract was influenced by the temperature, heating time, and pH. The maximum antiyeast activity was attained at the temperature range between 110 and 130 °C for the heating time range of 90 and 30 min, respectively. Reduced antiyeast activity occurred above 130 °C. More potent antiyeast activity was generated when the pH of the garlic extract was adjusted to and below 4.0. The sensitivity to the antiyeast activity of heated garlic or heated alliin was quite different depending on the yeast strain. Species belonging to Zygosaccharomyces were the least sensitive, while Candida utilis and Pichia membranaefaciens were among the most sensitive. The alliin content of the garlic was in the range of 0.5% to 1.32%. When garlic extracts were heated at 121 °C for 120 min, the content of allyl alcohol generated from alliin through thermal degradation was in the range of 0.08% to 0.16%. The allyl alcohol produced upon heating was positively proportional to the content of alliin in garlic. The antiyeast potency expressed as the minimum inhibitory concentration (MIC) was negatively proportional to the content of allyl alcohol and thus to the content of alliin.
Epidemiology of Human Metapneumovirus
Authors: Kahn Jeffrey S.
Published: July 2006

Since the discovery of human metapneumovirus (hMPV) in 2001, the virus has been identified worldwide. hMPV is a common respiratory pathogen, particularly in infants and young children. The virus is associated with both upper and lower respiratory tract infections and may be a trigger for asthma. At least two major genotypes of hMPV circulate during community outbreaks. Whether these genotypes represent distinct serotypes remains controversial. The major challenges faced by the medical and scientific communities are the understanding of the pathogenesis of hMPV disease and the development of a safe and effective vaccine to protect against infection and disease caused by this newly recognized respiratory virus.
Bats: Important Reservoir Hosts of Emerging Viruses
Authors: Calisher Charles H. , Childs James E. , Field Hume E. , Holmes Kathryn V. , Schountz Tony
Published: July 2006

Bats (order Chiroptera, suborders Megachiroptera [“flying foxes”] and Microchiroptera) are abundant, diverse, and geographically widespread. These mammals provide us with resources, but their importance is minimized and many of their populations and species are at risk, even threatened or endangered. Some of their characteristics (food choices, colonial or solitary nature, population structure, ability to fly, seasonal migration and daily movement patterns, torpor and hibernation, life span, roosting behaviors, ability to echolocate, virus susceptibility) make them exquisitely suitable hosts of viruses and other disease agents. Bats of certain species are well recognized as being capable of transmitting rabies virus, but recent observations of outbreaks and epidemics of newly recognized human and livestock diseases caused by viruses transmitted by various megachiropteran and microchiropteran bats have drawn attention anew to these remarkable mammals. This paper summarizes information regarding chiropteran characteristics and information regarding 66 viruses that have been isolated from bats. From these summaries, it is clear that we do not know enough about bat biology; we are doing too little in terms of bat conservation; and there remain a multitude of questions regarding the role of bats in disease emergence.
Application of Molecular Techniques to the Study of Hospital Infection
Authors: Singh Aparajita , Goering Richard V. , Simjee Shabbir , Foley Steven L. , Zervos Marcus J.
Published: July 2006

Nosocomial infections are an important source of morbidity and mortality in hospital settings, afflicting an estimated 2 million patients in United States each year. This number represents up to 5% of hospitalized patients and results in an estimated 88,000 deaths and 4.5 billion dollars in excess health care costs. Increasingly, hospital-acquired infections with multidrug-resistant pathogens represent a major problem in patients. Understanding pathogen relatedness is essential for determining the epidemiology of nosocomial infections and aiding in the design of rational pathogen control methods. The role of pathogen typing is to determine whether epidemiologically related isolates are also genetically related. To determine molecular relatedness of isolates for epidemiologic investigation, new technologies based on DNA, or molecular analysis, are methods of choice. These DNA-based molecular methodologies include pulsed-field gel electrophoresis (PFGE), PCR-based typing methods, and multilocus sequence analysis. Establishing clonality of pathogens can aid in the identification of the source (environmental or personnel) of organisms, distinguish infectious from noninfectious strains, and distinguish relapse from reinfection. The integration of molecular typing with conventional hospital epidemiologic surveillance has been proven to be cost-effective due to the associated reduction in the number of nosocomial infections. Cost-effectiveness is maximized through the collaboration of the laboratory, through epidemiologic typing, and the infection control department during epidemiologic investigations.
Pathogenesis ofHelicobacter pyloriInfection
Authors: Kusters Johannes G. , van Vliet Arnoud H. M. , Kuipers Ernst J.
Published: July 2006

Helicobacter pyloriis the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong.H. pyloriinfection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis ofH. pylori.
Tuberculosis Chemotherapy: the Influence of Bacillary Stress and Damage Response Pathways on Drug Efficacy
Authors: Warner Digby F. , Mizrahi Valerie
Published: July 2006

The global tuberculosis (TB) control effort is focused on interrupting transmission of the causative agent,
Mycobacterium tuberculosis
, through chemotherapeutic intervention in active infectious disease. The insufficiency of this approach is manifest in the inexorable annual increase in TB infection and mortality rates and the emergence of multidrug-resistant isolates. Critically, the limited efficacy of the current frontline anti-TB drug combination suggests that heterogeneity of host and bacillary physiologies might impair drug activity. This review explores the possibility that strategies enabling adaptation of
M. tuberculosis
to hostile in vivo conditions might contribute to the subversion of anti-TB chemotherapy. In particular, evidence that infecting bacilli are exposed to environmental and host immune-mediated DNA-damaging insults suggests a role for error-prone DNA repair synthesis in the generation of chromosomally encoded antibiotic resistance mutations. The failure of frontline anti-TB drugs to sterilize a population of susceptible bacilli is independent of genetic resistance, however, and instead implies the operation of alternative tolerance mechanisms. Specifically, it is proposed that the emergence of persister subpopulations might depend on the switch to an altered metabolic state mediated by the stringent response alarmone, (p)ppGpp, possibly involving some or all of the many toxin-antitoxin modules identified in the
M. tuberculosis
genome.
QUASINORMAL MODES OF UNRUH'S ACOUSTIC BLACK HOLE
Authors: SAAVEDRA JOEL
Published: July 2006

We study the sound perturbation of Unruh's acoustic geometry and present an exact expression for the quasinormal modes of this geometry. We found that the quasinormal frequencies are pure-imaginary which give a purely damped modes.
THE NEUTRALINO MASS: CORRELATION WITH THE CHARGINOS
Authors: BOZ MÜGE , PAK NAMIK K.
Published: July 2006

As the fundamental SU(2) supersymmetric parameters can be determined in the chargino sector, and the remaining fundamental parameters of the minimal supersymmetric extensions of the standard model can be analyzed in the neutralino sector, the two sectors can be correlated via these parameters. We have shown that for the CP-conserving case, the masses of all the neutralinos can be determined in terms of the chargino masses and tan β. In this case the neutralino masses are quite insensitive to the variations of tan β, they change by about 15% when tan β varies in the range from 5 to 50. In the CP-violating case, the neutralino masses are found to be quite sensitive to the variations of the CP-violating phase. For the heavier neutralinos the dependence of the masses to the CP-violating phase show complementary behavior at CP-violating points.
THE EVIDENCE FOR THE OBSERVATION OF 0νββ DECAY: THE IDENTIFICATION OF 0νββ EVENTS FROM THE FULL SPECTRA
Authors: KLAPDOR-KLEINGROTHAUS H. V. , KRIVOSHEINA I. V.
Published: July 2006

In this brief review, a description of the observed evidence for neutrinoless double beta3–5 in the 76 Ge experiment in Gran Sasso (Heidelberg–Moscow experiment) which has been operated with 11 kg enriched 76 Ge detectors in the period 1990–2003, is provided. Two different methods of pulse shape analysis have been used to select potential 0νββ events from the γ background of the measured spectrum — a selection by a neuronal net approach,3,4,16 and a selection by a new method comparing measured pulses with a library of pulse shapes of point-like events calculated from simulation of the electric field distribution in the detectors (see Refs. 6–8 and 37). The latter method also allows spatial localization of measured events. Both methods lead to selections of events at Qββ with almost no γ-background. The observed line at Qββ is identified as a 0νββ signal. It has a confidence level of more than 6σ.
ELECTROMAGNETIC FIELDS ON FRACTALS
Authors: TARASOV VASILY E.
Published: July 2006

Fractals are measurable metric sets with non-integer Hausdorff dimensions. If electric and magnetic fields are defined on fractal and do not exist outside of fractal in Euclidean space, then we can use the fractional generalization of the integral Maxwell equations. The fractional integrals are considered as approximations of integrals on fractals. We prove that fractal can be described as a specific medium.
DUALITY IN SUPERSYMMETRIC YANG–MILLS AND THE QUANTUM HALL EFFECT
Authors: DOLAN BRIAN P.
Published: July 2006

The evidence for the parallel rôles played by the modular group in [Formula: see text] supersymmetric Yang–Mills in (3+1) dimensions and the quantum Hall effect in (2+1) dimensions is reviewed. In both cases a subgroup of the full modular group acts as a map between different low energy phases of the theory, parametrised by a complex parameter in the upper-half-complex plane whose real part is a topological parameter and whose imaginary part is the coupling associated the kinetic term of the effective U(1) gauge theory. In the case of the quantum Hall effect experimental evidence in favour of the modular action is also reviewed.
HODGE DUALITY OPERATION AND ITS PHYSICAL APPLICATIONS ON SUPERMANIFOLDS
Authors: MALIK R. P.
Published: July 2006

An appropriate definition of the Hodge duality ⋆ operation on any arbitrary dimensional supermanifold has been a long-standing problem. We define a working rule for the Hodge duality ⋆ operation on the (2+2)-dimensional supermanifold parametrized by a couple of even (bosonic) space–time variables xμ(μ = 0, 1) and a couple of odd (fermionic) variables θ and [Formula: see text] of the Grassmann algebra. The Minkowski space–time manifold, hidden in the supermanifold and parametrized by xμ(μ = 0, 1), is chosen to be a flat manifold on which a two (1+1)-dimensional (2D) free Abelian gauge theory, taken as a prototype field theoretical model, is defined. We demonstrate the applications of the above definition (and its further generalization) for the discussion of the (anti-)co-BRST symmetries that exist for the field theoretical models of 2D and 4D free Abelian gauge theories considered on the four (2+2)- and six (4+2)-dimensional supermanifolds, respectively.
A CANONICAL ANALYSIS OF THE EINSTEIN–HILBERT IN FIRST ORDER FORM
Authors: KIRIUSHCHEVA N. , KUZMIN S. V. , MCKEON D. G. C.
Published: July 2006

Using the Dirac constraint formalism, we examine the canonical structure of the Einstein–Hilbert action [Formula: see text], treating the metric gαβ and the symmetric affine connection [Formula: see text] as independent variables. For d>2 tertiary constraints naturally arise; if these are all first class, there are d(d-3) independent variables in phase space, the same number that a symmetric tensor gauge field ϕμν possesses. If d = 2, the Hamiltonian becomes a linear combination of first class constraints obeying an SO (2, 1) algebra. These constraints ensure that there are no independent degrees of freedom. The transformation associated with the first class constraints is not a diffeomorphism when d = 2; it is characterized by a symmetric matrix ξμν. We also show that the canonical analysis is different if [Formula: see text] is used in place of gαβ as a dynamical variable when d = 2, as in d dimensions, [Formula: see text]. A comparison with the formalism used in the ADM analysis of the Einstein–Hilbert action in first order form is made by applying this approach in the two-dimensional case with hαβ and [Formula: see text] taken to be independent variables.
OBSERVABLE/HIDDEN SECTOR BROKEN SYMMETRY FOR SYMMETRIC BOUNDARY CONDITIONS
Authors: DUNDEE B. , PERKINS J. , CLEAVER G.
Published: July 2006

A four-dimensional heterotic string model of free fermionic construction is presented wherein mirror symmetry breaking between observable and hidden sector gauge groups occurs in spite of mirror symmetry between observable and hidden sector worldsheet fermion boundary conditions. The differentiation is invoked by an asymmetry in GSO projections necessarily resulting from the symmetry of the free fermionic boundary conditions. In the specific examples shown, an expected nonchiral Pati–Salam mirror universe model is transformed into a chiral model with enhanced hidden sector gauge symmetry and reduced observable sector gauge symmetry: [ SU (4)C ⊗ SU (2)L ⊗ SU (2)R]O ⊗ [ SU (4)C ⊗ SU (2)L ⊗ SU (2)R]H, is necessarily transformed into a chiral [ SU (4)C ⊗ SU (2)L]O ⊗ [ SO (10) ⊗ SU (2)R]H model because of an unavoidable asymmetry in GSO projections.
CHIRAL DYNAMICS FROM THE HADRONIC STRING: GENERAL FORMALISM
Authors: ANDRIANOV A. A. , ESPRIU D. , PRATS A.
Published: July 2006

Quantum Chromodynamics (QCD) at long distances can be described by the chiral Lagrangian. On the other hand there is overwhelming evidence that QCD and all non-Abelian theories admit an effective string description. Here we review a derivation of the (intrinsic) parity-even chiral Lagrangian by requiring that the propagation of the QCD string takes place on a background where chiral symmetry is spontaneously broken. Requiring conformal invariance leads to the equation of motion of the chiral Lagrangian. We then proceed to coupling the string degrees of freedom to external gauge fields and we recover in this way the covariant equations of motion of the gauge-invariant chiral Lagrangian at [Formula: see text]. We consider next the parity-odd part (Wess–Zumino–Witten) action and argue that this requires the introduction of the spin degrees of freedom (absent in the usual effective action treatment). We manage to reproduce the Wess–Zumino–Witten term in two dimensions (2D) in an unambiguous way. In 4D the situation is considerably more involved. We outline the modification of boundary interaction that is necessary to induce the parity-odd part of the chiral Lagrangian.
RADIAL EVOLUTION IN ANTI-DE SITTER SPACE–TIME
Authors: ILDERTON ANTON
Published: July 2006

In this paper we describe some properties of Green's functions which may be derived in either first or second quantization. We illustrate this with a factorization property of scalar fields in AdS space.
GRAVITATIONAL EFFECTS OF VARYING ALPHA STRINGS
Authors: MENEZES J. , SANTOS C. , AVELINO P. P.
Published: July 2006

We study spatial variations of the fine-structure constant in the presence of static straight cosmic strings in the weak-field approximation in Einstein gravity. We work in the context of a generic Bekenstein-type model and consider a gauge kinetic function linear in the scalar field. We determine an analytical form for the scalar field and the string metric at large distances from the core. We show that the gravitational effects of α-varying strings can be seen as a combination of the gravitational effects of global and local strings. We also verify that at large distances to the core the space–time metric is similar to that of a global string. We study the motion of test particles approaching from infinity and show that photons are scattered to infinity while massive particles are trapped in bounded trajectories. We also calculate an overall limit on the magnitude of the variation of α for a GUT string, by considering suitable cosmological constraints coming from the Equivalence Principle.
KLEIN PARADOX FOR OPTICAL SCATTERING FROM EXCITED TARGETS
Authors: PANELLA O. , SRIVASTAVA Y. N. , WIDOM A.
Published: July 2006

The well-known Klein paradox for the relativistic Dirac wave equation consists in the computation of possible "negative probabilities" induced by certain potentials in some regimes of energy. The paradox may be resolved by employing the notion of electron–positron pair production in which the number of electrons present in a process can increase. The Klein paradox also exists in the Maxwell's equations viewed as the wave equation for photons. In a medium containing "inverted energy populations" of excited atoms, e.g. in a LASER medium, one may again compute possible "negative probabilities." The resolution of the electromagnetic Klein paradox is that when the atoms decay, the final state may contain more photons then were contained the initial state. The optical theorem total cross-section for scattering photons from excited state atoms may then be computed as negative within a frequency band with matter induced amplification.
EVOLUTION OF THE CONCEPT OF THE VECTOR POTENTIAL IN THE DESCRIPTION OF FUNDAMENTAL INTERACTIONS
Authors: WU A. C. T. , YANG CHEN NING
Published: July 2006

Modern theories of fundamental interactions are based on the concept of "connections," a generalization of the vector potential A. How did this concept evolve in physics? We attempt in the present paper to trace this evolution, starting from the early 19th century. A schematic diagram which charts this evolution is exhibited (Fig. 1).
New Techniques to Evaluate Esophageal Function
Authors: Sifrim Daniel , Blondeau Kathleen
Published: July 2006

Classical techniques like videofluoroscopy, stationary manometry and ambulatory 24-hour pH-metry are routinely used in the clinic to study patients with dysphagia, chest pain and reflux-related symptoms. Although many patients can be accurately diagnosed and their therapy successfully guided with these techniques, in many other patients, non-obstructive dysphagia or chest pain cannot be attributed to clear fluoroscopic or manometric abnormalities. Furthermore, ambulatory 24-hour pH-metry often shows a poor association between spontaneous acid reflux events and esophageal or extraesophageal symptoms, particularly in patients ‘on’ treatment. Non-obstructive dysphagia can be assessed with high-resolution manometry to detect segmental disturbances of peristalsis, increase in pressure gradient across the lower esophageal sphincter (LES) or abnormal axial movement of the LES during esophageal spasm. Impedance evaluation of bolus transit is a non-radiological method that can evaluate the functional relevance of manometric abnormalities. Patients with non-cardiac chest pain that do not respond to proton pump inhibitor therapy can be further assessed with intraluminal high-frequency ultrasound to detect sustained esophageal contractions of the longitudinal muscle layer. Impedance planimetry, with multimodal esophageal stimulation, may contribute to evaluate the sensitivity to mechanical, thermal and chemical stimuli. Finally, patients with persistent symptoms of gastroesophageal reflux in spite of adequate treatment with proton pump inhibitors may still have weakly acidic reflux and/or bile reflux associated with their symptoms. These types of refluxates can now be detected with combinations of pH-impedance or pH-Bilitec monitoring. This review will describe the available new techniques to evaluate patients with non-obstructive dysphagia, non-cardiac chest pain and persistent gastroesophageal reflux symptoms.
Gastric Electrical Stimulation in Gastroparesis: Where Do We Stand?
Authors: Mönnikes Hubert , van der Voort Ivo R.
Published: July 2006

Gastroparesis is a chronic disabling condition of impaired gastric motility that results in decreased quality of life. Currently available medical therapy consists of prokinetic and/or antiemetic therapy, dietary modifications, and nutritional supplementation. For patients with medication-resistant gastroparesis a non-pharmacological therapy, gastric electric stimulation, has evolved over the last decade. Based on the frequency of the electrical stimulus, gastric electric stimulation can be classified into low- and high-frequency gastric electric stimulation. The first method aims to normalize gastric dysrhythmia and entrain gastric slow waves and accelerates gastric emptying, whereas high-frequency gastric electric stimulation is unable to restore normal gastric emptying, but nevertheless stunningly reduces symptoms, such as nausea and vomiting, re-establishes quality of life, nutritional state in all patients, and metabolic control in patients with diabetic gastroparesis. Gastric electric stimulation presents a new possibility in the treatment of gastroparesis.
Assessment of Gastrointestinal Sensation – A Review
Authors: Hobson Anthony R. , Aziz Qasim
Published: July 2006

Understanding the mechanisms of symptoms in patients with gastrointestinal disorders remains a great challenge. One of the major problems facing clinicians in this area is the limited information gained from subjective outcome measures commonly used to assess these conditions. To address this, various stimulation and recording techniques, commonly used by neurologists, have been adapted to study gastrointestinal sensory processing. This review article provides an overview of this expanding research area and discusses the advantages and disadvantages of each approach.