Showing papers by "Hiroshima University published in 2003"
TL;DR: In this paper, the authors proposed a method for machining aeroengine alloys with improved hardness, such as cubic boron nitride (CBN) tools, for high speed continuous machining.
970 citations
TL;DR: Antioxidant peptides in the acidic fraction were isolated by high-performance liquid chromatography on an ODS column and shown to possess the structures DSGVT, IEAEGE, DAQEKLE, EELDNALN, and VPSIDDQEELM.
Abstract: Hydrolysates obtained from porcine myofibrillar proteins by protease treatment (papain or actinase E) exhibited high antioxidant activity in a linolenic acid peroxidation system induced by Fe(2+). Hydrolysates produced by both papain and actinase E showed higher activities at pH 7.1 than at pH 5.4. The antioxidant activity of the papain hydrolysate was almost the same as that of vitamin E at pH 7.0. These hydrolysates possessed 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and chelating activity toward metal ions. Antioxidant peptides were separated from the papain hydrolysate by ion exchange chromatography. The acidic fraction obtained by this method exhibited higher activity than the neutral or basic fractions. Antioxidant peptides in the acidic fraction were isolated by high-performance liquid chromatography on an ODS column and shown to possess the structures DSGVT, IEAEGE, DAQEKLE, EELDNALN, and VPSIDDQEELM. The DAQEKLE peptide showed the highest activity among these peptides.
714 citations
TL;DR: There is no direct proof that the AhR is involved in the teratogenic effects of TCDD, but the role of AhR in the regulatory mechanism of xenobiotic‐metabolizing enzymes is investigated.
Abstract: Background:
The aryl hydrocarbon receptor (AhR or dioxin receptor) is a ligand-activated transcription factor that is considered to mediate pleiotropic biological responses such as teratogenesis, tumour promotion, epithelial hyperplasia and the induction of drug-metabolizing enzymes to environmental contaminants usually represented by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In contrast to the role of AhR in the regulatory mechanism of xenobiotic-metabolizing enzymes, there is no direct proof that the AhR is involved in the teratogenic effects of TCDD.
Results:
To gain insight into the physiological and teratogenic role of the AhR, we have used gene targeting in mice to disrupt the murine Ahr gene by homologous recombination. Ahr-null mice were viable and fertile and were apparently normal at birth, but displayed a slightly slower growth rate than wild-type mice for the first few weeks of life. When pregnant dams were administered with TCDD by gavage, at a dose of 40 μg/kg body weight at gestation day 12.5, none of the Ahr-null mutant foetuses were sensitive to the teratogenic effects of TCDD, although almost all wild-type foetuses suffered from cleft palate and hydronephrosis. In heterozygous Ahr+/− genotypes, nearly all foetuses suffered from hydronephrosis in response to TCDD treatment, while haplo-insufficiency was observed in the incidence of cleft palate.
Conclusion:
These results clearly show that the AhR is involved in the malformation of the palate and kidney in mouse embryos caused by TCDD and suggests that the mechanism of its involvement differs between the cleft palate and hydronephrosis.
626 citations
TL;DR: It is suggested that moderate-intensity aerobic exercise augments endothelium-dependent vasodilation in humans through the increased production of nitric oxide and that high-intensity exercise possibly increases oxidative stress.
Abstract: Background— Aerobic exercise enhances endothelium-dependent vasodilation in hypertensive patients, patients with chronic heart failure, and healthy individuals. However, it is unclear how the intensity of exercise affects endothelial function in humans. The purpose of the present study was to determine the effects of different intensities of exercise on endothelium-dependent vasodilation in humans. Methods and Results— We evaluated the forearm blood flow responses to acetylcholine, an endothelium-dependent vasodilator, and isosorbide dinitrate, an endothelium-independent vasodilator, before and after different intensities of exercise (mild, 25% Vo2max; moderate, 50% Vo2max; and high, 75% Vo2max; bicycle ergometers, 30 minutes, 5 to 7 times per week for 12 weeks) in 26 healthy young men. Forearm blood flow was measured using a mercury-filled Silastic strain-gauge plethysmograph. Twelve weeks of moderate-intensity exercise, but not mild- or high-intensity exercise, significantly augmented acetylcholine-i...
592 citations
TL;DR: In this article, the anisotropy parameter of the second harmonic of the azimuthal particle distribution has been measured with the PHENIX detector in Au+Au collisions at roots(NN)=200 GeV for identified and inclusive charged particle production at central rapidities.
Abstract: The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at roots(NN)=200 GeV for identified and inclusive charged particle production at central rapidities (eta 2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated.
570 citations
TL;DR: In this article, a simple, rapid and generalizable aerosol decomposition (spray pyrolysis) process for the continuous synthesis of nanoparticles with adjustable sizes, narrow size distribution, high crystallinity and good stoichiometry is described.
556 citations
08 Apr 2003
TL;DR: A human-assisting manipulator teleoperated by electromyographic signals and arm motions that can realize a new master-slave manipulator system that uses no mechanical master controller and that could assist the amputee in performing desktop work is proposed.
Abstract: This paper proposes a human-assisting manipulator teleoperated by electromyographic (EMG) signals and arm motions. The proposed method can realize a new master-slave manipulator system that uses no mechanical master controller. A person whose forearm has been amputated can use this manipulator as a personal assistant for desktop work. The control system consists of a hand and wrist control part and an arm control part. The hand and wrist control part selects an active joint in the manipulator's end-effector and controls it based on EMG pattern discrimination. The arm control part measures the position of the operator's wrist joint or the amputated part using a three-dimensional position sensor, and the joint angles of the manipulator's arm, except for the end-effector part, are controlled according to this position, which, in turn, corresponds to the position of the manipulator's joint. These control parts enable the operator to control the manipulator intuitively. The distinctive feature of our system is to use a novel statistical neural network for EMG pattern discrimination. The system can adapt itself to changes of the EMG patterns according to the differences among individuals, different locations of the electrodes, and time variation caused by fatigue or sweat. Our experiments have shown that the developed system could learn and estimate the operator's intended motions with a high degree of accuracy using the EMG signals, and that the manipulator could be controlled smoothly. We also confirmed that our system could assist the amputee in performing desktop work.
492 citations
TL;DR: In this paper, the authors measured the transverse momentum spectra of neutral pions in the range 1 < p_T < 10 GeV/c and showed that the pi^0 multiplicity in central reactions is significantly below the yields measured at the same squarert(s_NN) in peripheral Au+Au and p+p reactions scaled by the number of nucleon-nucleon collisions.
Abstract: Transverse momentum spectra of neutral pions in the range 1 < p_T < 10 GeV/c have been measured at mid-rapidity by the PHENIX experiment at RHIC in Au+Au collisions at sqrt(s_NN) = 200 GeV. The pi^0 multiplicity in central reactions is significantly below the yields measured at the same sqrt(s_NN) in peripheral Au+Au and p+p reactions scaled by the number of nucleon-nucleon collisions. For the most central bin, the suppression factor is ~2.5 at p_T = 2 GeV/c and increases to ~4-5 at p_T ~= 4 GeV/c. At larger p_T, the suppression remains constant within errors. The deficit is already apparent in semi-peripheral reactions and increases smoothly with centrality.
485 citations
01 Mar 2003-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The PHENIX detector as mentioned in this paper is designed to perform a broad study of A-A, p-A and p-p collisions to investigate nuclear matter under extreme conditions, and is used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon.
Abstract: The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution The detector consists of a large number of subsystems that are discussed in other papers in this volume The overall design parameters of the detector are presented (C) 2002 Elsevier Science BV All rights reserved
447 citations
TL;DR: This work designs low-complexity optimal PSAM for block transmissions over doubly selective channels using a basis expansion channel model and maximizes a tight lower bound on the average channel capacity that is shown to be equivalent to the minimization of the minimum mean-square channel estimation error.
Abstract: High data rates give rise to frequency-selective propagation, whereas carrier frequency-offsets and mobility-induced Doppler shifts introduce time-selectivity in wireless links. To mitigate the resulting time- and frequency-selective (or doubly selective) channels, optimal training sequences have been designed only for special cases: pilot symbol assisted modulation (PSAM) for time-selective channels and pilot tone-assisted orthogonal frequency division multiplexing (OFDM) for frequency-selective channels. Relying on a basis expansion channel model, we design low-complexity optimal PSAM for block transmissions over doubly selective channels. The optimality in designing our PSAM parameters consists of maximizing a tight lower bound on the average channel capacity that is shown to be equivalent to the minimization of the minimum mean-square channel estimation error. Numerical results corroborate our theoretical designs.
443 citations
TL;DR: The 2-twist trefoil is an example of a sphere that is knotted in 4-dimensional space as mentioned in this paper, and a proof is given in this paper that this sphere is distinct from the same sphere with its orientation reversed.
Abstract: The 2-twist spun trefoil is an example of a sphere that is knotted in 4-dimensional space. A proof is given in this paper that this sphere is distinct from the same sphere with its orientation reversed. Our proof is based on a state-sum invariant for knotted surfaces developed via a cohomology theory of racks and quandles (also known as distributive groupoids). A quandle is a set with a binary operation - the axioms of which model the Reidemeister moves in classical knot theory. Colorings of diagrams of knotted curves and surfaces by quandle elements, together with cocycles of quandles, are used to define state-sum invariants for knotted circles in 3-space and knotted surfaces in 4-space. Cohomology groups of various quandles are computed herein and applied to the study of the state-sum invariants. Non-triviality of the invariants is proved for a variety of knots and links, and conversely, knot invariants are used to prove non-triviality of cohomology for a variety of quandles.
TL;DR: In this article, angle-integrated photoemission measurements of carbon nanotubes (SWNTs) are reported, revealing an oscillation in the pi-electron density of states owing to one-dimensional van Hove singularities.
Abstract: The electronic transport properties of conventional three-dimensional metals are successfully described by Fermi-liquid theory. But when the dimensionality of such a system is reduced to one, the Fermi-liquid state becomes unstable to Coulomb interactions, and the conduction electrons should instead behave according to Tomonaga-Luttinger-liquid (TLL) theory. Such a state reveals itself through interaction-dependent anomalous exponents in the correlation functions, density of states and momentum distribution of the electrons. Metallic single-walled carbon nanotubes (SWNTs) are considered to be ideal one-dimensional systems for realizing TLL states. Indeed, the results of transport measurements on metal-SWNT and SWNT-SWNT junctions have been attributed to the effects of tunnelling into or between TLLs, although there remains some ambiguity in these interpretations. Direct observations of the electronic states in SWNTs are therefore needed to resolve these uncertainties. Here we report angle-integrated photoemission measurements of SWNTs. Our results reveal an oscillation in the pi-electron density of states owing to one-dimensional van Hove singularities, confirming the one-dimensional nature of the valence band. The spectral function and intensities at the Fermi level both exhibit power-law behaviour (with almost identical exponents) in good agreement with theoretical predictions for the TLL state in SWNTs.
TL;DR: The yield ratio does not show the suppression observed in central Au+Au collisions at RHIC, but there is a small enhancement in the yield of high momentum particles.
Abstract: Transverse momentum spectra of charged hadrons with p(T)<8 GeV/c and neutral pions with p(T)<10 GeV/c have been measured at midrapidity by the PHENIX experiment at BNL RHIC in d+Au collisions at sqrt[s(NN)]=200 GeV. The measured yields are compared to those in p+p collisions at the same sqrt[s(NN)] scaled up by the number of underlying nucleon-nucleon collisions in d+Au. The yield ratio does not show the suppression observed in central Au+Au collisions at RHIC. Instead, there is a small enhancement in the yield of high momentum particles.
TL;DR: In this article, an overview of recent research on porous alumina science and technology, nanohole array self-organization conditions and mechanisms, various methods of nanostructure formation using porous aluminum templates, optical and magnetic nanofabrication, perspectives on electronic nano device fabrication and chemical/biological sensors and membranes.
Abstract: Nanofabrication by self-organization methods has attracted much attention owing to the fact that it enables mass production without the use of expensive lithographical tools, such as an electron beam exposure system. Porous alumina can be fabricated electrochemically through anodic oxidation of aluminum by means of such a self-organization method, yielding highly ordered arrays of nanoholes several hundreds down to several tens of nanometers in size. This paper is an overview of recent research on porous alumina science and technology, nanohole array self-organization conditions and mechanisms, various methods of nanostructure formation using porous alumina templates, optical and magnetic nanofabrication, perspectives on electronic nano device fabrication and chemical/biological sensors and membranes.
TL;DR: The observations suggest that Rev1 plays a role in mediating protein–protein interactions among DNA polymerases required for TLS, and the precise function(s) of these interactions during TLS remains to be determined.
Abstract: Polκ and Rev1 are members of the Y family of DNA polymerases involved in tolerance to DNA damage by replicative bypass [translesion DNA synthesis (TLS)]. We demonstrate that mouse Rev1 protein physically associates with Polκ. We show too that Rev1 interacts independently with Rev7 (a subunit of a TLS polymerase, Polζ) and with two other Y-family polymerases, Polι and Polη. Mouse Polκ, Rev7, Polι and Polη each bind to the same ∼100 amino acid C-terminal region of Rev1. Furthermore, Rev7 competes directly with Polκ for binding to the Rev1 C-terminus. Notwith standing the physical interaction between Rev1 and Polκ, the DNA polymerase activity of each measured by primer extension in vitro is unaffected by the complex, either when extending normal primer-termini, when bypassing a single thymine glycol lesion, or when extending certain mismatched primer termini. Our observations suggest that Rev1 plays a role(s) in mediating protein–protein interactions among DNA polymerases required for TLS. The precise function(s) of these interactions during TLS remains to be determined.
TL;DR: The viability of transgenic silkworms as a tool for producing useful proteins in bulk is demonstrated by immunoblotting, collagenase-sensitivity tests, and amino acid sequencing.
Abstract: We describe the generation of transgenic silkworms that produce cocoons containing recombinant human collagen. A fusion cDNA was constructed encoding a protein that incorporated a human type III procollagen mini-chain with C-propeptide deleted, a fibroin light chain (L-chain), and an enhanced green fluorescent protein (EGFP). This cDNA was ligated downstream of the fibroin L-chain promoter and inserted into a piggyBac vector. Silkworm eggs were injected with the vectors, producing worms displaying EGFP fluorescence in their silk glands. The cocoons emitted EGFP fluorescence, indicating that the promoter and fibroin L-chain cDNAs directed the synthesized products to be secreted into cocoons. The presence of fusion proteins in cocoons was demonstrated by immunoblotting, collagenase-sensitivity tests, and amino acid sequencing. The fusion proteins from cocoons were purified to a single electrophoretic band. This study demonstrates the viability of transgenic silkworms as a tool for producing useful proteins in bulk.
TL;DR: It is demonstrated that eight different vRNA segments must be present for efficient virion formation and that sequences within the coding region of (and thus unique to) the neuraminidase vRNA possess a signal that drives incorporation of this segment into virions.
Abstract: The genome of influenza A virus is comprised of eight viral RNA (vRNA) segments. Although the products of all eight vRNA segments must be present for viral replication, little is known about the mechanism(s) responsible for incorporation of these segments into virions. Two models have been proposed for the generation of infectious virions containing eight vRNA segments. The random-incorporation model assumes a common structural feature in all the vRNAs, enabling any combination of vRNAs to be incorporated randomly into virions. The selective-incorporation model predicts the presence of specific structures in each vRNA segment, leading to the incorporation of a set of eight vRNA segments into virions. Here we demonstrate that eight different vRNA segments must be present for efficient virion formation and that sequences within the coding region of (and thus unique to) the neuraminidase vRNA possess a signal that drives incorporation of this segment into virions. These findings indicate a unique contribution from individual vRNA segments and thus suggest a selective (rather than random) mechanism of vRNA recruitment into virions. The neuraminidase vRNA incorporation signal and others yet to be identified should provide attractive targets for the attenuation of influenza viruses in vaccine production and the design of new antiviral drugs.
TL;DR: In this paper, a theoretical analysis indicates that the structural stability of the droplet and the hydrodynamic effects during the drying process play important roles in controlling the morphology of the resulting particles.
TL;DR: During cytokinesis, MgcRacGAP, previously known as a GAP for Rac/Cdc42, is functionally converted to a RhoGAP through phosphorylation by Aurora B, which induces latent GAP activity toward RhoA in vitro.
Journal Article•
TL;DR: Baseline plasma gh Relin level was elevated in cachectic patients with lung cancer, and follow-up plasma ghrelin level increased in patients with anorexia after chemotherapy, suggesting increased ghrelIn may represent a compensatory mechanism under catabolic-anabolic imbalance in cachectica patients with Lung cancer.
Abstract: Purpose: Ghrelin, a novel growth hormone-releasing peptide,has been shown to cause a positive energy balance by stimulating food intake and inducing adiposity. We sought to investigate the pathophysiology of ghrelin in cachexia associated with lung cancer. Experimental design: Plasma ghrelin level was measured in 43 patients with lung cancer and 21 control subjects. Patients with lung cancer were divided into two groups: patients with cachexia ( n = 21) and those without cachexia ( n = 22). Results: Plasma ghrelin level did not significantly differ between all patients with lung cancer and controls (157 ± 10 versus 132 ± 8 fmol/ml, P = 0.1). However, plasma ghrelin level was significantly higher in patients with cachexia than in those without cachexia (180 ± 17 versus 135 ± 10 fmol/ml, P = 0.011). Furthermore, plasma ghrelin level increased significantly in patients with decreased food intake after chemotherapy (from 136 ± 11 fmol/ml to 170 ± 16 fmol/ml on day 8, 179 ± 20 fmol/ml on day 21 after start of chemotherapy), although plasma ghrelin level did not significantly change in those without decreased food intake. Conclusions: Baseline plasma ghrelin level was elevated in cachectic patients with lung cancer, and follow-up plasma ghrelin level increased in patients with anorexia after chemotherapy. Considering the positive energy effects induced by ghrelin, increased ghrelin may represent a compensatory mechanism under catabolic–anabolic imbalance in cachectic patients with lung cancer.
TL;DR: GnIH has the potential to regulate gonadotropin release at more than one level, and its distribution is suggestive of multiple regulatory functions in the central nervous system.
Abstract: Gonadotropin-releasing hormone (GnRH) regulates reproduction in all vertebrates. Until recently, an antagonistic neuropeptide for gonadotropin was unknown. The discovery of an RFamide peptide in quail that inhibits gonadotropin release in vitro raised the possibility of direct hypothalamic inhibition of gonadotropin release. This peptide has now been named gonadotropin-inhibitory hormone (GnIH). We investigated GnIH presence in the hypothalamus of two seasonally breeding songbird species, house sparrows (Passer domesticus) and song sparrows (Melospiza melodia). Using immunocytochemistry (ICC), GnIH-containing neurones were localized in both species in the paraventricular nucleus, with GnIH-containing fibres visible in multiple brain locations, including the median eminence and brainstem. Double-label ICC with light microscopy and fluorescent ICC with confocal microscopy indicate a high probability of colocalization of GnIH with GnRH neurones and fibres within the avian brain. It is plausible that GnIH could be acting at the level of the hypothalamus to regulate gonadotropin release as well as at the pituitary gland. In a photoperiod manipulation experiment, GnIH-containing neurones were larger in birds at the termination of the breeding season than at other times, consistent with a role for this neuropeptide in the regulation of seasonal breeding. We have yet to elucidate the dynamics of GnIH synthesis and release at different times of year, but the data imply temporal regulation of this peptide. In summary, GnIH has the potential to regulate gonadotropin release at more than one level, and its distribution is suggestive of multiple regulatory functions in the central nervous system.
27 Oct 2003
TL;DR: A newly developed high-speed multi-fingered robotic hand that can close its joints at 180 deg per 0.1 s, and have an output force of about 28 N.
Abstract: In this paper we introduce a newly developed high-speed multi-fingered robotic hand. The hand has 8-joints and 3-fingers. A newly developed small harmonic drive gear and a high-power mini actuator are fitted in each finger link, and a strain gauge sensor is in each joint. The weight of the hand module is only 0.8 kg, but high-speed motion and high-power grasping are possible. The hand can close its joints at 180 deg per 0.1 s, and the fingertips have an output force of about 28 N. The hand system is controlled by a massively parallel vision system. Experimental results are shown in which a falling object was caught by the high-speed hand.
TL;DR: In this paper, a water extract of fresh propolis from Brazil was prepared using a lipid peroxidation model system, and the scavenging activity against superoxide anion radical was found to be high, at 50 and 100 mg/ml, completely inhibited the production of superoxide.
TL;DR: Bach1 functions as a hypoxia-inducible repressor for the HO-1 gene, thereby contributing to fine-tuning of oxygen homeostasis in human cells, indicating the inter-species difference in the hypoxic regulation ofHO-1 expression.
TL;DR: In this paper, the synthesis and structural characterization of new nickel-containing Mg-Al layered double hydroxides (LDH) was presented, which adopt a structure in which nickel, chelated with ethylenediaminetetraacetate to a divalent anion [Ni(EDTA)]2−, is nested between brucite-like layers of LDH.
TL;DR: The association between midlife risk factors and the development of vascular dementia (VaD) or Alzheimer's disease (AD) 25 to 30 years later is investigated.
Abstract: OBJECTIVES: To investigate the association between midlife risk factors and the development of vascular dementia (VaD) or Alzheimer's disease (AD) 25 to 30 years later. DESIGN: A prevalence study within a longitudinal cohort study. SETTING: Subjects in the Adult Health Study (a prospective cohort study begun in 1958) have been followed through biennial medical examinations in Hiroshima, Japan. PARTICIPANTS: One thousand seven hundred seventy-four subjects in Hiroshima, Japan born before September 1932 (1,660 with no dementia, 114 with dementia (51 with AD, and 38 with VaD) diagnosed from 1992 to 1997 according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria). MEASUREMENTS: The subjects were examined for effect on dementia of sex, age, education, atomic bomb radiation dose, and midlife factors associated with risk (smoking, alcohol intake, physical activity, dietary habits, systolic blood pressure (SBP), body mass index, and history of diabetes mellitus) that had been evaluated in 1965-1970. RESULTS: VaD prevalence increased significantly with age, higher SBP, and lower milk intake. The odds ratios of VaD for age (in 5-year increments), SBP (10 mmHg increments), and milk intake (almost daily/less than four times a week) were 1.29, 1.33, and 0.35, respectively. The risk factors for VaD were compatible with the risk factors for stroke in this study population. AD prevalence increased significantly with age and lower education. Other midlife factors and radiation dose did not show any significant association with VaD or AD. CONCLUSION: Increased SBP and low milk intake in midlife were associated with VaD detected 25 to 30 years later. Early behavioral control of the risk factors for vascular disease might reduce the risk of dementia.
TL;DR: The antioxidant activities of the essential oil of Origanum syriacum was slightly lower than those of ascorbic acid or BHT, so the oil can be considered an effective natural antioxidant.
Abstract: In the present study, essential oil from the leaves of Syrian oreganum [Origanum syriacum L. (Lauraceae)] grown in Turkish state forests of the Dortyol district, Turkey, was obtained by steam distillation. The chemical composition of oil was analysed by GC and GC-MS, and was found to contain 49.02% monoterpenes, 36.60% oxygenated monoterpenes and 12.59% sesquiterpenes. The major components are as follows: gamma-terpinene, carvacrol, p-cymene and beta-caryophyllene. Subsequently, the reducing power, antioxidant and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activities of the essential oil were studied. The reducing power was compared with ascorbic acid, and the other activities were compared with 2,6-di-tert-butyl-4-methyl phenol (BHT, butylated hydroxytoluene). The results showed that the activities were concentration dependent. The antioxidant activities of the oil were slightly lower than those of ascorbic acid or BHT, so the oil can be considered an effective natural antioxidant. Antimicrobial activities of the essential oil from the leaves of Origanum syriacum was also determined on 16 microorganisms tested using the agar-disc diffusion method, and showed antimicrobial activity against 13 of these.
TL;DR: In this paper, the authors used an open-flow gas exchange system with an infrared gas analyser to determine the contribution of root respiration to soil respiration in the growing season.
Abstract: A trenching method was used to determine the contribution of root respiration to soil respiration. Soil respiration rates in a trenched plot (R trench) and in a control plot (R control) were measured from May 2000 to September 2001 by using an open-flow gas exchange system with an infrared gas analyser. The decomposition rate of dead roots (R D) was estimated by using a root-bag method to correct the soil respiration measured from the trenched plots for the additional decaying root biomass. The soil respiration rates in the control plot increased from May (240–320 mg CO2 m−2 h−1) to August (840–1150 mg CO2 m−2 h−1) and then decreased during autumn (200–650 mg CO2 m−2 h−1). The soil respiration rates in the trenched plot showed a similar pattern of seasonal change, but the rates were lower than in the control plot except during the 2 months following the trenching. Root respiration rate (R r) and heterotrophic respiration rate (R h) were estimated from R control, R trench, and R D. We estimated that the contribution of R r to total soil respiration in the growing season ranged from 27 to 71%. There was a significant relationship between Rh and soil temperature, whereas R r had no significant correlation with soil temperature. The results suggest that the factors controlling the seasonal change of respiration differ between the two components of soil respiration, R r and R h.
TL;DR: It is demonstrated that ubiquitylation‐dependent regulation of Bim levels is critical for controlling apoptosis and activation of OCs.
Abstract: Osteoclasts (OCs) undergo rapid apoptosis without trophic factors, such as macrophage colony‐stimulating factor (M‐CSF). Their apoptosis was associated with a rapid and sustained increase in the pro‐apoptotic BH3‐only Bcl‐2 family member Bim. This was caused by the reduced ubiquitylation and proteasomal degradation of Bim that is mediated by c‐Cbl. Although the number of OCs was increased in the skeletal tissues of bim−/− mice, the mice exhibited mild osteosclerosis due to reduced bone resorption. OCs differentiated from bone marrow cells of bim−/− animals showed a marked prolongation of survival in the absence of M‐CSF, compared with bim+/+ OCs, but the bone‐resorbing activity of bim−/− OCs was significantly reduced. Overexpression of a degradation‐resistant lysine‐free Bim mutant in bim−/− cells abrogated the anti‐apoptotic effect of M‐CSF, while wild‐type Bim did not. These results demonstrate that ubiquitylation‐dependent regulation of Bim levels is critical for controlling apoptosis and activation of OCs.
TL;DR: The substitution of a Tris-citric acid diluent composition with trehalose significantly improves the freezability of goat spermatozoa and the cryoprotective effects oftrehalose observed in this study may be due to enhanced sperm membrane fluidity before freezing.
Abstract: In an attempt to find a suitable freezing method for goat semen, two experiments were conducted to study the influence of trehalose on the cryopreservation of goat spermatozoa. In experiment 1, goat spermatozoa were frozen in trehalose extender (0.375 M) alone (100%) or at different combinations of trehalose with Tris-citric acid-glucose (TCG) extender (0%, 25%, 50%, 75%). Final concentrations of 20% (v:v) egg yolk and 4% (v:v) glycerol were employed in the extenders (osmolality = 370, pH = 7). Sperm motility was assessed using a computer-assisted sperm analysis system and acrosome integrity was assessed using fluorescein isothiocyanate-labeled peanut agglutinin (FITC-PNA). The sperm-motility parameters improved significantly by increasing the concentration of trehalose (P < 0.05) and significantly high recovery rates for the motility parameters were also achieved by a high concentration of trehalose (P < 0.05). Motility of the frozen-thawed spermatozoa after a 3-h incubation improved significantly with increasing concentrations of trehalose in the extender (P < 0.05). The 75% and 100% trehalose extenders yielded a significant increase in the percentage of spermatozoa with intact acrosome (P < 0.05). In experiment 2, merocyanine 540/Yo-Pro staining was used to study the influence of trehalose on membrane fluidity compared with that of sucrose and TCG. Percentage of cells with high merocyanine fluorescence was significantly higher in spermatozoa treated with trehalose than sucrose or TCG (P < 0.05), indicating a significantly highest membrane fluidity of sperm samples extended with trehalose solution. We thus conclude that the substitution of a Tris-citric acid diluent composition with trehalose significantly improves the freezability of goat spermatozoa. Furthermore, the cryoprotective effects of trehalose observed in this study may be due to enhanced sperm membrane fluidity before freezing.