bluuebunny/crossref_metadata_2025 huggingface dataset:
Silicon nanocrystal-based photosensor on low-temperature polycrystalline-silicon panels
Authors: Chiang Wen-Jen , Chen Chih-Yang , Lin Chrong-Jung , King Ya-Chin , Cho An-Thung , Peng Chia-Tian , Chao Chih-Wei , Lin Kun-Chih , Gan Feng-Yuan
Published: August 2007

A photodetector, comprising a layer of silicon nanocrystals that is sandwiched between two electrodes, is proposed and demonstrated in a photosensing application on low-temperature polysilicon panels. Laser annealing of silicon-rich oxide films can form nanocrystals that respond optimally to a certain absorption spectrum of a light source. These silicon nanocrystals are smaller than 10nm in diameter, which size determines the effectiveness of their quantum confinement, and promote electron-hole pair generation in the photosensing region because of their direct band gap. Besides obtaining a photosensitivity that is comparable to that of a p-i-n diode, which is currently used in low-temperature polysilicon technology, the sensor maximizes the photosensing area of a pixel by its stacked structure.
Reduced injection current induced blueshift in an InGaN∕GaN quantum-well light-emitting diode of prestrained growth
Authors: Huang Chi-Feng , Chen Cheng-Yen , Lu Chih-Feng , Yang C. C.
Published: August 2007

The authors demonstrate the smaller blueshift in increasing injection current level of an InGaN∕GaN quantum-well (QW) light-emitting diode (LED) of a longer electroluminescence (EL) peak wavelength based on the prestrained growth technique when compared with the result of a LED of a shorter EL peak wavelength based on the conventional growth technique. The smaller blueshift can be attributed to more contribution to light emission from the deeper QWs of higher indium contents when the injection current level is increased in the prestrain sample. It can also be attributed to the stronger carrier localization because of the stronger composition clustering in the prestrain sample of higher indium contents. Carrier localization can reduce the influences of the quantum-confined Stark effect and its screening process.
Intense ultraviolet upconversion luminescence from Tm3+∕Yb3+:β-YF3 nanocrystals embedded glass ceramic
Authors: Chen Daqin , Wang Yuansheng , Yu Yunlong , Huang Ping
Published: August 2007

The infrared to ultraviolet upconversion emissions of Tm3+ I61→F43 (346nm) and D21→H63 (362nm) transitions, originating from the five- and four-photon upconversion processes, respectively, were observed in the Tm3+∕Yb3+ codoped precursor glass and glass ceramic containing β-YF3 nanocrystals. The ultraviolet luminescence of the glass ceramic is 30 times stronger than that of the precursor glass, which could be attributed to the decreased probability of the F23→F43 transition and the increased cross relaxation of F23+H43→H63+D21 resulted from the partition of rare earth ions into nanocrystals.
IR imaging using a cantilever-based focal plane array fabricated by deep reactive ion etching technique
Authors: Wang Xin , Ma Shenglin , Yu Xiaomei , Liu Ming , Liu Xiaohua , Zhao Yuejin
Published: August 2007

The authors report on a novel substrate-free cantilever-based focal plane array (FPA) fabricated by a deep reactive ion etching technique and discuss its performance as an uncooled infrared imager. A visible optical readout was designed to simultaneously measure the deflections of all the cantilevers in the FPA. The noise equivalent temperature difference (NETD) of our FPA can be reduced by 60% compared to the one fabricated by sacrificial layer technique and some cantilevers exhibited NETD of 375mK, approaching the theoretical prediction of 89.7mK. The FPA has a bending response to temperature of 86nm∕K and a response time of 21ms.
One by one single-electron transport in nanomechanical Coulomb blockade shuttle
Authors: Azuma Yasuo , Hatanaka Teruyoshi , Kanehara Masayuki , Teranishi Toshiharu , Chorley Simon , Prance Jonathan , Smith Charles G. , Majima Yutaka
Published: August 2007

Transport of electrons through a Au nanodot has been observed under a nanomechanical vibration of a Au nanodot on cantilever that consists of scanning tunneling microscopy probe/vacuum/Au nanodot/cantilever. In the probe tunneling current-distance characteristics, a constant probe current of 2ef has been observed as a plateau region, where f is an eigenfrequency of the cantilever of 86MHz. The authors discuss this quantized tunneling current in relation to one by one single-electron transport per cycle of operation in nanomechanical Coulomb blockade shuttle.
Cloning in companion animal, non-domestic and endangered species: can the technology become a practical reality?
Authors: Mastromonaco Gabriela F. , King W. Allan
Published: August 2007

Somatic cell nuclear transfer (SCNT) can provide a unique alternative for the preservation of valuable individuals, breeds and species. However, with the exception of a handful of domestic animal species, successful production of healthy cloned offspring has been challenging. Progress in species that have little commercial or research interest, including many companion animal, non-domestic and endangered species (CANDES), has lagged behind. In this review, we discuss the current and future status of SCNT in CANDES and the problems that must be overcome to improve pre- and post-implantation embryo survival in order for this technology to be considered a viable tool for assisted reproduction in these species.
Germ cell transplantation for the propagation of companion animals, non-domestic and endangered species
Authors: Dobrinski I. , Travis A. J.
Published: August 2007

The transplantation of spermatogonial stem cells between males results in a recipient animal producing spermatozoa carrying a donor’s haplotype. First pioneered in rodents, this technique has now been used in several animal species. Importantly, germ cell transplantation was successful between unrelated, immuno-competent large animals, whereas efficient donor-derived spermatogenesis in rodents requires syngeneic or immuno-compromised recipients. Transplantation requires four steps: recipient preparation, donor cell isolation, transplantation and identifying donor-derived spermatozoa. There are two main applications for this technology. First, genetic manipulation of isolated germ line stem cells and subsequent transplantation will result in production of transgenic spermatozoa. Transgenesis through the male germ line has tremendous potential in species in which embryonic stem cells are not available and somatic cell nuclear transfer and reprogramming pose several problems. Second, spermatogonial stem cell transplantation within or between species offers a means of preserving the reproductive potential of genetically valuable individuals. This might have significance in the captive propagation of non-domestic animals of high conservation value. Transplantation of germ cells is a uniquely valuable approach for the study, preservation and manipulation of male fertility in mammalian species.
The GABA
A
receptor α1 subunit epilepsy mutation A322D inhibits transmembrane helix formation and causes proteasomal degradation
Authors: Gallagher Martin J. , Ding Li , Maheshwari Ankit , Macdonald Robert L.
Published: August 2007

A form of autosomal dominant juvenile myoclonic epilepsy is caused by a nonconservative missense mutation, A322D, in the GABA
A
receptor α1 subunit M3 transmembrane helix. We reported previously that the A322D mutation reduced total and surface α1(A322D) subunit protein and that residual α1(A322D) subunit resided in the endoplasmic reticulum. Here, we demonstrate that the reduction in α1(A322D) expression results from rapid endoplasmic reticulum-associated degradation of the α1(A322D) subunit through the ubiquitin–proteasome system. We provide direct evidence that the α1(A322D) subunit misfolds and show that in at least 33% of α1(A322D) subunits, M3 failed to insert into the lipid bilayer. We constructed a series of mutations in the M3 domain and empirically determined the apparent free energy cost (ΔG
app
) of membrane insertion failure, and we show that the ΔG
app
correlated directly with the recently elucidated transmembrane sequence code (ΔG
Lep
). These data provide a biochemical mechanism for the pathogenesis of this epilepsy mutation and demonstrate that ΔG
Lep
predicts the efficiency of lipid partitioning of a naturally occurring protein's transmembrane domain expressed
in vivo
. Finally, we calculated the ΔΔG
Lep
for 277 known transmembrane missense mutations associated with Charcot–Marie–Tooth disease, diabetes insipidus, retinitis pigmentosa, cystic fibrosis, and severe myoclonic epilepsy of infancy and showed that the majority of these mutations also are likely to destabilize transmembrane domain membrane insertion, but that only a minority of the mutations would be predicted to be as destabilizing as the A322D mutation.
TRF2 is required for repair of nontelomeric DNA double-strand breaks by homologous recombination
Authors: Mao Zhiyong , Seluanov Andrei , Jiang Ying , Gorbunova Vera
Published: August 2007

TRF2 (telomeric repeat binding factor 2) is an essential component of the telomeric cap, where it forms and stabilizes the T-loop junctions. TRF2 forms the T-loops by stimulating strand invasion of the 3′ overhang into duplex DNA. TRF2 also has been shown to localize to nontelomeric DNA double-strand breaks, but its functional role in DNA repair has not been examined. Here, we present evidence that TRF2 is involved in homologous recombination (HR) repair of nontelomeric double-strand breaks. Depletion of TRF2 strongly inhibited HR and delayed the formation of Rad51 foci after γ-irradiation, whereas overexpression of TRF2 stimulated HR. Depletion of TRF2 had no effect on nonhomologous end-joining, and overexpression of TRF2 inhibited nonhomologous end-joining. We propose, based on our results and on the ability of TRF2 to mediate strand invasion, that TRF2 plays an essential role in HR by facilitating the formation of early recombination intermediates.
Maternal nutrient supplementation counteracts bisphenol A-induced DNA hypomethylation in early development
Authors: Dolinoy Dana C. , Huang Dale , Jirtle Randy L.
Published: August 2007

The hypothesis of fetal origins of adult disease posits that early developmental exposures involve epigenetic modifications, such as DNA methylation, that influence adult disease susceptibility.
In utero
or neonatal exposure to bisphenol A (BPA), a high-production-volume chemical used in the manufacture of polycarbonate plastic, is associated with higher body weight, increased breast and prostate cancer, and altered reproductive function. This study shows that maternal exposure to this endocrine-active compound shifted the coat color distribution of viable yellow agouti (
A

vy

) mouse offspring toward yellow by decreasing CpG (cytosine-guanine dinucleotide) methylation in an intracisternal A particle retrotransposon upstream of the
Agouti
gene. CpG methylation also was decreased at another metastable locus, the CDK5 activator-binding protein (
Cabp

IAP

). DNA methylation at the
A

vy

locus was similar in tissues from the three germ layers, providing evidence that epigenetic patterning during early stem cell development is sensitive to BPA exposure. Moreover, maternal dietary supplementation, with either methyl donors like folic acid or the phytoestrogen genistein, negated the DNA hypomethylating effect of BPA. Thus, we present compelling evidence that early developmental exposure to BPA can change offspring phenotype by stably altering the epigenome, an effect that can be counteracted by maternal dietary supplements.
Stable reduction of CCR5 by RNAi through hematopoietic stem cell transplant in non-human primates
Authors: An Dong Sung , Donahue Robert E. , Kamata Masakazu , Poon Betty , Metzger Mark , Mao Si-Hua , Bonifacino Aylin , Krouse Allen E. , Darlix Jean-Luc , Baltimore David , Qin F. Xiao-Feng , Chen Irvin S. Y.
Published: August 2007

RNAi is a powerful method for suppressing gene expression that has tremendous potential for therapeutic applications. However, because endogenous RNAi plays a role in normal cellular functions, delivery and expression of siRNAs must be balanced with safety. Here we report successful stable expression in primates of siRNAs directed to chemokine (c-c motif) receptor 5 (CCR5) introduced through CD34+ hematopoietic stem/progenitor cell transplant. After hematopoietic reconstitution, to date 14 months after transplant, we observe stably marked lymphocytes expressing siRNAs and consistent down-regulation of chemokine (c-c motif) receptor 5 expression. The marked cells are less susceptible to simian immunodeficiency virus infection
ex vivo.
These studies provide a successful demonstration that siRNAs can be used together with hematopoietic stem cell transplant to stably modulate gene expression in primates and potentially treat blood diseases such as HIV-1.
Three classes of glucocerebrosidase inhibitors identified by quantitative high-throughput screening are chaperone leads for Gaucher disease
Authors: Zheng Wei , Padia Janak , Urban Daniel J. , Jadhav Ajit , Goker-Alpan Ozlem , Simeonov Anton , Goldin Ehud , Auld Douglas , LaMarca Mary E. , Inglese James , Austin Christopher P. , Sidransky Ellen
Published: August 2007

Gaucher disease is an autosomal recessive lysosomal storage disorder caused by mutations in the glucocerebrosidase gene. Missense mutations result in reduced enzyme activity that may be due to misfolding, raising the possibility of small-molecule chaperone correction of the defect. Screening large compound libraries by quantitative high-throughput screening (qHTS) provides comprehensive information on the potency, efficacy, and structure–activity relationships (SAR) of active compounds directly from the primary screen, facilitating identification of leads for medicinal chemistry optimization. We used qHTS to rapidly identify three structural series of potent, selective, nonsugar glucocerebrosidase inhibitors. The three structural classes had excellent potencies and efficacies and, importantly, high selectivity against closely related hydrolases. Preliminary SAR data were used to select compounds with high activity in both enzyme and cell-based assays. Compounds from two of these structural series increased N370S mutant glucocerebrosidase activity by 40–90% in patient cell lines and enhanced lysosomal colocalization, indicating chaperone activity. These small molecules have potential as leads for chaperone therapy for Gaucher disease, and this paradigm promises to accelerate the development of leads for other rare genetic disorders.
Neurotrophins enhance retinal pigment epithelial cell survival through neuroprotectin D1 signaling
Authors: Mukherjee Pranab K. , Marcheselli Victor L. , Barreiro Sebastian , Hu Jane , Bok Dean , Bazan Nicolas G.
Published: August 2007

Integrity of retinal pigment epithelial cells is necessary for photoreceptor survival and vision. The essential omega-3 fatty acid, docosahexaenoic acid, attains its highest concentration in the human body in photoreceptors and is assumed to be a target for lipid peroxidation during cell damage. We have previously shown, in contrast, that docosahexaenoic acid is also the precursor of neuroprotectin D1 (NPD1), which now we demonstrate, acts against apoptosis mediated by A2E, a byproduct of phototransduction that becomes toxic when it accumulates in aging retinal pigment epithelial (RPE) cells and in some inherited retinal degenerations. Furthermore, we show that neurotrophins, particularly pigment epithelium-derived factor, induce NPD1 synthesis and its polarized apical secretion. Moreover, docosahexaenoic acid (DHA) elicits a concentration-dependent and selective potentiation of pigment epithelial-derived factor-stimulated NPD1 synthesis and release through the apical RPE cell surface. The bioactivity of signaling activated by pigment epithelium-derived factor and DHA uncovered synergistic cytoprotection with concomitant NPD1 synthesis when cells were challenged with oxidative stress. Also, DHA and pigment epithelium-derived factor synergistically modify the expression of Bcl-2 family members, activating antiapoptotic proteins and decreasing proapoptotic proteins, and by attenuating caspase 3 activation during oxidative stress. Thus, our findings demonstrate that DHA-derived NPD1 protects against RPE cell damage mediated by aging/disease-induced A2E accumulation. Also, our results identify neurotrophins as regulators of NPD1 and of its polarized apical efflux from RPE cells. Taken together, these findings imply NPD1 may elicit autocrine actions on RPE cells and paracrine bioactivity in cells located in the proximity of the interphotoreceptor matrix.
Hand Hygiene and Glove Use Behavior in an Italian Hospital
Authors: Pan Angelo , Mondello Placido , Posfay-Barbe Klara , Catenazzi Patrizia , Grandi Annise , Lorenzotti Silvia , Patroni Andrea , Poli Nadia , Soavi Laura , Carnevale Giuseppe
Published: August 2007

In an Italian hospital, we observed that hand hygiene was performed in 638 (19.6%) of 3,253 opportunities, whereas gloves were worn in 538 (44.2%) 1,218 of opportunities. We observed an inverse correlation between the intensity of care and the rate of hand hygiene compliance (R2=0.057; P<.001), but no such association was observed for the rate of glove use compliance (R2 = 0.014; P = .078). Rates of compliance with hand hygiene and glove use recommendations follow different behavioral patterns.
Fecal Carriage of Extended-Spectrum β-Lactamase–ProducingEscherichia coliandKlebsiella pneumoniaein Patients and Asymptomatic Healthy Individuals
Authors: Kader Abdulrahman Abdulla , Kumar Angamuthu , Kamath Katapadi Ananthkrishna
Published: August 2007

Fecal carriage of extended-spectrum β-lactamase (ESBL)-producing organisms was assessed in 272 inpatients, 162 outpatients, and 426 asymptomatic healthy individuals. Of 860 stool samples cultured, 152 (17.7%) yielded ESBL-producing organisms. Isolates were recovered from 71 (26.1%) of the inpatients, 25 (15.4%) of the outpatients, and 56 (13.1%) of the healthy individuals. These findings suggest that the community could be a reservoir of ESBL-producing organisms.
Age Limit Does Not Replace Serologic Testing for Determination of Immune Status for Measles
Authors: Uçkay Ilker , Hugonnet Stéphane , Kaiser Laurent , Sax Hugo , Pittet Didier
Published: August 2007

Adults more than 40 years old are not necessarily immune to measles. A measles outbreak that involved healthcare workers occurred after contact with a 44-year-old patient. Results of a hospitalwide program of mass screening revealed that 117 (4.5%) of 2,600 individuals tested seronegative for measles; 31 (26.1%) of these 117 individuals were more than 40 years old.
Value of Whole-Body Washing With Chlorhexidine for the Eradication of Methicillin-ResistantStaphylococcus aureus:A Randomized, Placebo-Controlled, Double-Blind Clinical Trial
Authors: Wendt C. , Schinke S. , Württemberger M. , Oberdorfer K. , Bock-Hensley O. , von Baum H.
Published: August 2007

Background.

Whole-body washing with antiseptic solution has been widely used as part of eradication treatment for colonization with methicillin-resistantStaphylococcus aureus(MRSA), but evidence for the effectiveness of this measure is limited.

Objective.

To study the efficacy of whole-body washing with chlorhexidine for the control of MRSA.

Design.

Randomized, placebo-controlled, double-blinded clinical trial.

Setting.

University Hospital of Heidelberg and surrounding nursing homes.

Patients.

MRSA carriers who were not treated concurrently with antibiotics effective against MRSA were eligible for the study.

Intervention.

Five days of whole-body washing with either 4% chlorhexidine solution (treatment group) or with a placebo solution. All patients received mupirocin nasal ointment and chlorhexidine mouth rinse. The outcome was evaluated 3, 4, 5, 9, and 30 days after treatment with swab samples taken from several body sites.

Results.

Of 114 patients enrolled in the study (56 in the treatment group and 58 in the placebo group), 11 did not finish treatment (8 from the treatment group and 3 from the placebo group [P= .02]). At baseline, the groups did not differ with regard to age, sex, underlying condition, site of MRSA colonization, or history of MRSA eradication treatment. Eleven patients were MRSA-free 30 days after treatment (4 from the treatment group and 7 from the placebo group [P= .47]). Only groin-area colonization was significantly better eradicated by the use of chlorhexidine. The best predictor for total eradication was a low number of body sites positive for MRSA. Adverse effects were significantly more frequent in the treatment group than in the placebo group (any symptom, 71% vs 33%) but were reversible in most cases.

Conclusion.

Whole-body washing can reduce skin colonization, but it appears necessary to extend eradication measures to the gastrointestinal tract, wounds, and/or other colonized body sites if complete eradication is the goal.

Trial Registration.

ClinicalTrials.gov identifier: NCT00266448.
Hand Hygiene Compliance Rates After an Educational Intervention in a Neonatal Intensive Care Unit
Authors: Raskind Craig H. , Worley Sarah , Vinski Joan , Goldfarb Johanna
Published: August 2007

An observational study was performed at a level III neonatal intensive care unit to assess the impact of a hand hygiene promotion educational program on rates of compliance with hand hygiene on entrance into the unit. There was an initial improvement in the rate of compliance at 1 month after the intervention (from 89% [168 of 189 opportunities] to 100% [212 of 212 opportunities]; P<.001], but the rate decreased to the baseline rate at 3 months (89% [85 of 96 opportunities]).
Severe Surgical Site Infection in Community Hospitals: Epidemiology, Key Procedures, and the Changing Prevalence of Methicillin-Resistant Staphylococcus aureus
Authors: Anderson Deverick J. , Sexton Daniel J. , Kanafani Zeina A. , Auten Grace , Kaye Keith S.
Published: August 2007

Objective.

To characterize the epidemiology of severe (ie, nonsuperficial) surgical site infection (SSI) in community hospitals.

Methods.

SSI data were collected prospectively at 26 community hospitals in the southeastern United States. Two analyses were performed: (1) a study of the overall prevalence rates of SSI and the prevalence rates of SSI due to specific pathogens in 2005 at all participating hospitals and (2) a prospective study of consecutive surgical procedures at 9 of the 26 community hospitals from 2000 through 2005.

Results.

In 2005, a total of 1,010 SSIs occurred after 89,302 procedures (prevalence rate, 1.13 infections per 100 procedures). Methicillin-resistant S. aureus (MRSA) was the pathogen most commonly recovered (from 175 SSIs). Trend data from 2000 through 2005 demonstrated that the prevalence rate of MRSA SSI almost doubled during this period, increasing from 0.12 infections per 100 procedures (95% confidence interval [CI], 0.12-0.13) to 0.23 infections per 100 procedures (95% CI, 0.22-0.24) (P<.0001). In adjusted analysis, MRSA SSI was significantly more prevalent at the end of the study period than at the beginning (prevalence rate ratio, 1.48 [95% CI, 1.36-1.61]; P<.0001).

Conclusions.

MRSA was the pathogen that most commonly caused SSI in our network of community hospitals during 2005. The prevalence of MRSA SSI has increased significantly over the past 6 years.
Talin Influences the Dynamics of the Myosin VII-Membrane Interaction
Authors: Galdeen Shawn A. , Stephens Stephen , Thomas David D. , Titus Margaret A.
Published: August 2007

Myosin VII (M7) and talin are ancient and ubiquitous actin-binding proteins with conserved roles in adhesion. Talin serves to link membrane receptors to the underlying actin cytoskeleton and forms a complex with M7 in Dictyostelium. The levels of talinA are tightly linked to M7 levels in Dictyostelium. Cells lacking M7 exhibit an 80% decrease in steady-state levels of talinA, whereas increased levels of M7 result in concomitant increases in total talinA. In contrast, changes in talinA levels do not affect M7 levels. Immunoprecipitation reveals that talinA and M7 are associated with each other in membrane fractions. Fluorescence recovery after photobleaching experiments on green fluorescent protein (GFP)-M7 cells expressing different levels of the M7 and talinA show that changes in the overall amounts of these two proteins influences the dynamics of membrane-associated M7. The recovery of GFP-M7 on the membrane is faster in cells lacking talinA and limited in the presence of excess amounts of talinA and M7. These results establish that M7 stabilizes talinA in the cytosol and, in return, talinA regulates the residence time of M7 at the plasma membrane, suggesting that these two proteins are both part of the same dynamic adhesion complex on the plasma membrane.
CDK-5 Regulates the Abundance of GLR-1 Glutamate Receptors in the Ventral Cord ofCaenorhabditis elegans
Authors: Juo Peter , Harbaugh Tom , Garriga Gian , Kaplan Joshua M.
Published: August 2007

The proline-directed kinase Cdk5 plays a role in several aspects of neuronal development. Here, we show that CDK-5 activity regulates the abundance of the glutamate receptor GLR-1 in the ventral cord of Caenorhabditis elegans and that it produces corresponding changes in GLR-1–dependent behaviors. Loss of CDK-5 activity results in decreased abundance of GLR-1 in the ventral cord, accompanied by accumulation of GLR-1 in neuronal cell bodies. Genetic analysis of cdk-5 and the clathrin adaptin unc-11 AP180 suggests that CDK-5 functions prior to endocytosis at the synapse. The scaffolding protein LIN-10/Mint-1 also regulates GLR-1 abundance in the nerve cord. CDK-5 phosphorylates LIN-10/Mint-1 in vitro and bidirectionally regulates the abundance of LIN-10/Mint-1 in the ventral cord. We propose that CDK-5 promotes the anterograde trafficking of GLR-1 and that phosphorylation of LIN-10 may play a role in this process.
Melanosome Maturation Defect in Rab38-deficient Retinal Pigment Epithelium Results in Instability of Immature Melanosomes during Transient Melanogenesis
Authors: Lopes Vanda S. , Wasmeier Christina , Seabra Miguel C. , Futter Clare E.
Published: August 2007

Pathways of melanosome biogenesis in retinal pigment epithelial (RPE) cells have received less attention than those of skin melanocytes. Although the bulk of melanin synthesis in RPE cells occurs embryonically, it is not clear whether adult RPE cells continue to produce melanosomes. Here, we show that progression from pmel17-positive premelanosomes to tyrosinase-positive mature melanosomes in the RPE is largely complete before birth. Loss of functional Rab38 in the “chocolate” (cht) mouse causes dramatically reduced numbers of melanosomes in adult RPE, in contrast to the mild phenotype previously shown in skin melanocytes. Choroidal melanocytes in cht mice also have reduced melanosome numbers, but a continuing low level of melanosome biogenesis gradually overcomes the defect, unlike in the RPE. Partial compensation by Rab32 that occurs in skin melanocytes is less effective in the RPE, presumably because of the short time window for melanosome biogenesis. In cht RPE, premelanosomes form but delivery of tyrosinase is impaired. Premelanosomes that fail to deposit melanin are unstable in both cht and tyrosinase-deficient RPE. Together with the high levels of cathepsin D in immature melanosomes of the RPE, our results suggest that melanin deposition may protect the maturing melanosome from the activity of lumenal acid hydrolases.
Proper Recruitment of γ-Tubulin and D-TACC/Msps to EmbryonicDrosophilaCentrosomes Requires Centrosomin Motif 1
Authors: Zhang Jiuli , Megraw Timothy L.
Published: August 2007

Centrosomes are microtubule-organizing centers and play a dominant role in assembly of the microtubule spindle apparatus at mitosis. Although the individual binding steps in centrosome maturation are largely unknown, Centrosomin (Cnn) is an essential mitotic centrosome component required for assembly of all other known pericentriolar matrix (PCM) proteins to achieve microtubule-organizing activity at mitosis in Drosophila. We have identified a conserved motif (Motif 1) near the amino terminus of Cnn that is essential for its function in vivo. Cnn Motif 1 is necessary for proper recruitment of γ-tubulin, D-TACC (the homolog of vertebrate transforming acidic coiled-coil proteins [TACC]), and Minispindles (Msps) to embryonic centrosomes but is not required for assembly of other centrosome components including Aurora A kinase and CP60. Centrosome separation and centrosomal satellite formation are severely disrupted in Cnn Motif 1 mutant embryos. However, actin organization into pseudocleavage furrows, though aberrant, remains partially intact. These data show that Motif 1 is necessary for some but not all of the activities conferred on centrosome function by intact Cnn.
Qigong Ameliorates Symptoms of Chronic Fatigue: A Pilot Uncontrolled Study
Authors: Craske Naropa J. Mike , Turner Warren , Zammit-Maempe Joseph , Lee Myeong Soo
Published: August 2007

Traditional Chinese Medicine practitioners consider that chronic fatigue reflects a disharmony and depletion in the supply of qi in the body. Qigong is one of the traditional complementary interventions used to strengthen qi through self‐practice, and to manage the state of qi to prevent and cure disease. The aim of this study is to assess whether qigong could be used to manage the symptoms of chronic fatigue. Eighteen Caucasian, British female participants were recruited, taught a qigong routine during weekly classes over 6 months, and asked to practice it daily for 15 min. Participants completed the core set of the RAND Medical Outcomes Study questionnaire (RAND MOS) and a sleep diary during the 2‐week baseline control period, and at 3 and 6 months following the start of the trial. The qigong intervention resulted in significant changes in sleep rate score and in the following subscales of the RAND MOS: SF36 Vitality, Sleep Problems, Social Activity, Social Activity Limitation due to Health, Health Distress, Mental Health Index and Psychological Well‐being. Qigong seems to improve factors related to chronic fatigue such as sleep, pain, mental attitude and general mobility after 3 and 6 months. Qigong′s positive effects indicate that it represents a potentially safe method of treatment for chronic fatigued patients. However, we cannot completely discount the possible influence of placebo effects, and more objective clinical measures are needed to reproduce our findings with long‐term follow‐up in a randomized, controlled study involving a larger number of subjects.
Eastern Baltic cod (Gadus morhua callarias) stock dynamics: extending the analytical assessment back to the mid-1940s
Authors: Eero Margit , Köster Friedrich W. , Plikshs Maris , Thurow Fritz
Published: August 2007

Eero, M., Köster, F. W., Plikshs, M., and Thurow, F. 2007. Eastern Baltic cod (Gadus morhua callarias) stock dynamics: extending the analytical assessment back to the mid-1940s. – ICES Journal of Marine Science, 64: 1257–1271. The status of the eastern Baltic cod (Gadus morhua callarias) stock has been assessed annually by ICES since 1966. To understand better the causes of stock fluctuations and to evaluate human impact on the stock relative to natural variability, longer time-series than currently available are needed. To achieve this, data back to the mid-1940s were compiled to extend the analytical assessment. Estimates are provided of stock development and its exploitation for a 20-year period before the start of the current assessment. The quality of the data and the credibility of the historical estimates are discussed. Considerable fluctuations in cod biomass and recruitment in the pre-assessment years were identified. Stock size was estimated to be relatively low after the Second World War, then increased during the first half of the 1950s, but did not reach the high levels of abundance subsequently observed in the early 1980s, and then declined towards the mid-1960s. Fishing mortality was low after the Second World War but increased rapidly in the second half of the 1950s, reaching the high levels observed since the 1980s.
Long-term enrichment enhances the cognitive behavior of the aging neurogranin null mice without affecting their hippocampal LTP
Authors: Huang Freesia L. , Huang Kuo-Ping , Boucheron Catherine
Published: August 2007

Neurogranin (Ng), a PKC substrate, is abundantly expressed in brain regions important for cognitive functions. Deletion of Ng caused severe deficits in spatial learning and LTP in the hippocampal CA1 region of mice. These Ng−/− mice also exhibit deficits in the amplification of their hippocampal signaling pathways critical for learning and memory. A short-term exposure to an enriched environment failed to improve their behavioral performances. Here, we showed that a long-term enrichment protocol for the aging mice was beneficial to the Ng−/− as well as Ng+/+ and Ng+/− mice in preventing age-related cognitive decline. Enrichment also caused an increase in the hippocampal CREB level of all three genotypes and Ng level of Ng+/+ and Ng+/− mice, but not that of αCaMKII or ERK. Interestingly, hippocampal slices of these enriched aging Ng−/− mice, unlike those of Ng+/+ and Ng+/− mice, did not show enhancement in the high frequency stimulation (HFS)-induced LTP in the CA1 region. It appears that the learning and memory processes in these enriched aging Ng−/− mice do not correlate with the HFS-induced LTP, which is facilitated by Ng. These results demonstrated that long-term enrichment for the aging Ng−/− mice may improve their cognitive function through an Ng-independent plasticity pathway.
Constitutive Fms‐like tyrosine kinase 3 activation results in specific changes in gene expression in myeloid leukaemic cells
Authors: Kim Kyu‐Tae , Baird Kristin , Davis Sean , Piloto Obdulio , Levis Mark , Li Li , Chen Peili , Meltzer Paul , Small Donald
Published: August 2007

Constitutively activating internal tandem duplication (ITD) mutations of the receptor tyrosine kinase FLT3 (Fms‐like tyrosine kinase 3) play an important role in leukaemogenesis. We have examined, by cDNA microarray analysis, the changes in gene expression induced by FLT3/ITD or constitutively activated wild type FLT3 signalling. A limited set of genes was consistently affected by FLT3 inhibition. In confirmation of their FLT3 dependence, these genes returned toward pretreatment levels of expression after reversal of FLT3 inhibition. Several of the most significantly affected genes are involved in the RAS/mitogen‐activated protein kinase, Janus kinase/signal transducer and activator of transcription and phosphatidylinositol 3 kinase (PI3K)/AKT pathways. These data suggest that constitutively activated FLT3 works through multiple signal transduction pathways. PIM1, MYC and CCND3 were chosen from this gene set to explore their biological roles. Knock‐down of these genes by small interfering RNA showed that these genes play important roles in constitutively activated FLT3 expressing cells. The alterations of the gene expression profiles in these cells help to further elucidate the mechanisms of FLT3‐mediated leukaemogenesis.
Waldenström macroglobulinaemia
Authors: Fonseca Rafael , Hayman Suzanne
Published: August 2007

Over time, Waldenström macroglobulinaemia (WM) has evolved conceptually from a clinical syndrome to a distinct clinicopathological entity. Progress is being made in standardization of the disease definition and treatment response criteria, although nosologic controversies persist. According to the Second International Workshop on WM, the disease is defined as a B‐cell neoplasm characterized by a lymphoplasmacytic infiltrate in the bone marrow, with an associated immunoglobulin (Ig) M paraprotein. Disease symptoms are often divided into those related to tumour infiltration and those related to the rheological effects of the monoclonal IgM. As with other low‐grade lymphomas, asymptomatic patients are observed only, with treatment reserved for symptomatic patients. There is no standard treatment for WM and choices include rituximab, alkylating agents, purine nucleoside analogues, alone or in combination, as well as autologous peripheral blood stem cell transplant in eligible patients. Novel treatments, such as bortezomib, oblimersen sodium, perifosine and others are being evaluated.
Meteorological influences on algal bloom potential in a nutrient‐rich blackwater river
Authors: PHLIPS EDWARD J. , HENDRICKSON JOHN , QUINLAN ERIN L. , CICHRA M.
Published: August 2007

1. The effect of variability in rainfall on the potential for algal blooms was examined for the St Johns River in northeast Florida. Water chemistry and phytoplankton data were collected at selected sites monthly from 1993 through 2003. Information on rainfall and estimates of water turnover rates were used in the analyses of trends in phytoplankton biomass.

2. Major trends in rainfall and runoff within the lower St Johns River catchment over the 10‐year study period were marked by both significant drought and flood periods. Autumn and winter rainfall patterns were strongly correlated with the range of Pacific sea surface temperature anomalies associated with El Niño events and La Niña periods. The effect of these major shifts in rainfall was evident in the strong relationship to replacement rates for water within the lower St Johns River.

3. The eutrophic status of the river was reflected in the high concentrations of nitrogen and phosphorus observed at all sampling sites, with total nitrogen concentrations up to 3100 μg L−1 and total phosphorus concentrations up to 180 μg L−1.

4. While it is clear that the high phytoplankton biomass and frequent blooms that characterize the freshwater portions of the lower St Johns River are fundamentally based on nutrient status, the expression of that potential was strongly correlated to water replacement rates, as revealed by the inverse relationship between phytoplankton biovolume increase and water turnover rate, with an R2 of 0.80 for the major bloom season. The sensitivity of algal blooms to rainfall patterns over the 10‐year study period suggest that longer‐term temporal and spatial shifts in rainfall, such as multi‐decadal cycles and the global‐warming phenomenon, will also influence the frequency and intensity of algal blooms.
Effects of continuous or rotational grazing of two perennial ryegrass varieties on the chemical composition of the herbage and the performance of finishing lambs
Authors: Marley C. L. , Fraser M. D. , Fisher W. J. , Forbes A. B. , Jones R. , Moorby J. M. , MacRae J. C. , Theodorou M. K.
Published: August 2007

Plant breeding has developed perennial ryegrass varieties with increased concentrations of water‐soluble carbohydrates (WSCs) compared with conventional varieties. Water‐soluble carbohydrates are major metabolic and storage components in ryegrass. Therefore, if perennial ryegrass herbage is allowed to grow to greater heights it should contain higher water‐soluble carbohydrates concentrations, for example as under rotational grazing rather than continuous grazing by livestock. This study investigated this hypothesis and measured the performance of lambs grazed rotationally and continuously. Replicated plots of the variety AberDart (bred to express high WSC concentrations) or the variety Fennema were grazed by a core group of ten male Cheviot lambs for 10 weeks. Lambs were weighed and replicate forage samples were taken every 7 d. Concentrations of WSC in AberDart herbage were significantly (P < 0·05), but not substantially, higher than those in Fennema herbage. Rotational grazing did not increase the differential in WSC concentration between the AberDart and Fennema varieties. However, there was a tendency (P = 0·07) for lambs rotationally grazing the AberDart swards to have a higher final live weight than lambs grazing the Fennema swards. Overall, lamb performance was increased when either perennial ryegrass variety was rotationally rather than continuously grazed (P < 0·001).
Genotypic variation in patterns of root distribution, nitrate interception and response to moisture stress of a perennial ryegrass (Lolium perenneL.) mapping population
Authors: Crush J. R. , Easton H. S. , Waller J. E. , Hume D. E. , Faville M. J.
Published: August 2007

Genotypic variation in patterns of root distribution, nitrate interception and response to moisture stress were assessed in both parents and 198 progeny of a perennial ryegrass (Lolium perenneL.) full‐sibling mapping population. This was carried out in metre‐deep tubes of sand culture in a glasshouse experiment. The proportion of root dry matter (DM) weight in the top 10 cm of sand ranged from 0·33 to 0·75 and values of log10(1 − K), whereKis the constant for an exponential model relating root DM weight and root depth, also showed wide variation among genotypes. The proportion of a pulse of15N recovered in whole plants ranged from 0·124 to 0·431. There was a positive linear correlation between the proportion of15N recovered and plant total DM weight, but no relationship between nitrate interception and patterns of distribution of DM weight of roots. Some genotypes responded to moisture stress by increasing root growth, and in others root growth was inhibited. It is concluded that this below‐ground variability in root variables may be an evolutionary adaptation by plant populations to survive heterogeneity in soil biotic and edaphic factors.
Seasonal distribution of herbage mass and nutritive value of Prairiegrass (Bromus catharticus Vahl)
Authors: Belesky D. P. , Ruckle J. M. , Abaye A. O.
Published: August 2007

A reliable supply of herbage is a crucial feature of forage‐based livestock systems. Forage resources with winter‐active growth habits can help extend the growing season in early spring and late autumn in regions with mild‐winter conditions while drought‐ and heat‐tolerant plants help meet herbage needs during summer in humid temperate regions. The prairiegrass (Bromus catharticus, Vahl) cultivars, Grassland Dixon and Grasslands Lakota, provide resistance to foliar disease and cold in addition to sustained productivity when soil moisture is low, and could be useful over a wide range of growing conditions. The cultivars were sown in spring or summer to determine seasonal distribution of productivity and nutritive value of herbage grown in a cool‐temperate region. Stands established rapidly regardless of sowing time or cultivar and were virtually pure prairiegrass once plants were well‐established. Stand composition of broadcast sowings tended to be stable in subsequent growing seasons, whereas the amount of prairiegrass varied in no‐till stands. In the growing seasons after establishment, cumulative dry matter (DM) yield of Lakota was similar regardless of when it was sown, whereas DM yield of Dixon differed with sowing time and was less in spring‐ than summer‐planted stands. Rapid stand establishment, significant late‐season yield, consistent concentrations of crude protein, non‐structural carbohydrate and total digestible nutrients in herbage, and dominance of sward composition, suggest that prairiegrass cultivars, Dixon and Lakota, are excellent resources for forage‐based livestock production systems in humid temperate conditions.
Yield and nitrogen concentration of above‐ and below‐ground biomasses of red clover cultivars in pure stands and in mixtures with three grass species in northern Europe
Authors: Hakala K. , Jauhiainen L.
Published: August 2007

Three red clover (Trifolium pratense) varieties differing in productivity and winter hardiness, Jokioinen, Betty and Ilte, were sown in a 2‐year (2003–2004) pot experiment in pure stands and mixtures with the grasses, timothy (Phleum pratense), tall fescue (Festuca arundinacea) and meadow fescue (Festuca pratensis). Grass growth dominated until fertilizer‐N, applied when the stands were sown, was depleted. Timothy was the least competitive of the grass species. Red clover variety Ilte produced the highest dry‐matter (DM) yields. Variety Betty yielded less, but allocated as much biomass to the root and stubble (soil‐bound) fraction as variety Ilte. Variety Jokioinen allocated least to the soil‐bound fraction. While the root structure and the starch concentration of the crown‐root area were similar in all varieties, the high ratio of soil‐bound: harvested fractions could be a key to the higher winter survival and higher DM yields of Betty under field conditions. At the end of the experiment, 3–5 g N pot−1 (49–81 g m−2) had been harvested and 0·7–1·5 g N pot−1 (11–24 g m−2) was left in the soil‐bound fraction, amounts depending on the red clover variety and grass mixture, with pure clover stands containing the highest N amounts. Because of the high N concentrations in the biomass of red clover, the proportion of red clover and conditions prevailing during canopy and root death in mixed stands are crucial for N mineralization and incorporation into new growth.
Effects of shrub encroachment on herbage production and nutritive value in semi‐arid Mediterranean grasslands
Authors: Zarovali M. P. , Yiakoulaki M. D. , Papanastasis V. P.
Published: August 2007

There is limited information on the effects of the increase in the density of shrubs on herbage production and nutritive value of natural grasslands in the Mediterranean region, currently facing major land use changes. Herbage production of drymatter (herbaceous fractions, of plant functional groups and by species), crude protein (CP), neutral‐detergent fibre (NDF), acid‐detergent fibre (ADF), acid‐detergent lignin (ADL) and hemicellulose concentrations and in vitro organic matter digestibility were determined at the time of peak of annual growth across four types of grassland vegetation each characterized by different shrub cover regimes. A sharp reduction in herbage production and a reduction in nutritive value were found as a result of the increase in shrub cover. These changes appeared to be closely related to the shift in plant functional groups detected as shrub density increased. Herbage production from grasses and legumes was found to be more sensitive to shrub cover changes than herbage production from forbs, whereas, as grassland types became denser, annual species were gradually replaced by perennials and C4 grasses by C3 ones. The impact of shrub encroachment on Mediterranean grasslands is discussed in relation to their use by livestock.