bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial variability of evapotranspiration of old-growth cypress forest using remote sensing — a case study of Chilan Mountain cypress forest in Taiwan
Authors: Wu Chih-Da , Cheng Chi-Chuan , Chuang Yung-Chung
Published: June 2012

The Chilan Mountain cypress forest, northeastern Taiwan, is the only one where the genus Chamaecyparis is situated in a subtropical region. The health of a forest ecosystem is closely tied to the evapotranspiration (ET) of water through forests. This study focused on estimating the ET of old-growth cypress in the Chilan Mountain area and investigated its spatial variability in different watershed divisions using remote sensing. Our methods included applying hybrid image classification to generate land cover maps using Landsat-5 images, calculating habitat characteristics of old-growth using the Surface Energy Balance Algorithm for Land (SEBAL), investigating spatial variability of ET in relation to environmental parameters, and examining the gap-snag effect on old-growth cypress ET. The results indicated that the study area was classified into three land cover types (i.e., old-growth, non-old growth, and others). Old-growth had lower values in net radiance, the normalized difference vegetation index (NDVI), and daily ET than did non-old-growth. Watershed divisions at various scales did cause the variation on old-growth ET characteristics according to the selected parameters and the number of parameters for predicting the value of ET. Finally, ET between gap-snag and non-gap-snag habitats was statistically different. A higher proportion in gap-snag composition would lead to a lower value in daily ET and the NDVI.
Decomposition and change in N and organic composition of small-diameter Douglas-fir woody debris over 23 years
Authors: Preston C.M. , Trofymow J.A. , Nault J.R.
Published: June 2012

Managing second-growth forests for multiple benefits requires enhanced information on decomposition of woody debris generated during forestry operations. Experimental thinning and biomass sampling at the Shawnigan Lake Research Forest on southern Vancouver Island facilitated retrospective sampling of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) stem sections (4.9–21.5 cm diameter) from 0 to 23 years after cutting. A sigmoidal pattern of density loss was observed, while a single-exponential fit gave a decay rate (k) of 0.058 year–1. Initial N concentrations were higher in bark than in sapwood and heartwood, and all increased during decay, while C/N ratios declined to around 175 for wood and 70 for bark. Nitrogen contents initially increased but tended to decline after about 50% C loss. Solid-state 13C nuclear magnetic resonance spectroscopy showed little change in organic composition, consistent with white-rot fungal decay, with only a few 19-year samples showing large increases in lignin typical of extensive brown-rot decay. Hydrolyzable monosaccharides of wood and bark were dominated by glucose followed by mannose, xylose, galactose, and arabinose. For wood, the mole fraction of mannose decreased with decomposition, whereas those of glucose, arabinose, and galactose increased slightly and that of xylose remained constant for both brown and white rot. Our results support indications that decomposition of smaller diameter woody debris from managed conifer forests will likely be dominated by white-rot fungi, leaving residues high in cellulose rather than in lignin.
STUDY OF ISOMERIC CROSS-SECTION RATIO AND PRE-EQUILIBRIUM FRACTION IN PROTON AND ALPHA PARTICLE INDUCED NUCLEAR REACTIONS ON 197Au
Authors: SATHEESH B. , MUSTHAFA M. M. , SINGH B. P. , PRASAD R.
Published: June 2012

Excitation functions for the reactions 197 Au(p,n) 197g Hg and 197 Au(p,n) 197m Hg have been measured over the energy ranges from threshold up to 20 MeV using stacked foil activation technique. The isomeric cross-section ratio σm/(σm+σg) for the formation of 197g, m Hg was determined. The excitation functions and isomeric cross-section ratios were calculated for the reactions 197 Au(p,n) 197g,m Hg , 197 Au(p,2n) 196 Hg , 197 Au(p,3n) 195g,m Hg , 197 Au(p,4n) 194 Hg , 197 Au(p,5n) 193g,m Hg , 197 Au (α, n )200 Tl , 197 Au (α, 2n )199 Tl , 197 Au (α, 3n )198g,m Tl , 197 Au (α, 4n )197 Tl and 197 Au (α, 5n )196g,m Tl from reaction threshold up to 40 MeV for proton induced reactions and 80 MeV for alpha induced reactions. The results were compared with the theoretical cross-sections calculated by means of the code EMPIRE-II and with the available literature data, which makes use of the Hauser Feshbach model for the compound nuclear calculations and the exciton model for the pre-equilibrium emission part. The isomeric cross-section ratio is found to depend strongly on the relative spins of the isomeric and ground state, energy difference between the levels, presence of intermediate states and some dependence on decay modes and on the onset of pre-equilibrium emission.
ON HOFFMAN'S RELATION FOR MULTIPLE ZETA-STAR VALUES
Authors: WAKABAYASHI NORIKO
Published: June 2012

The multiple zeta values are natural generalization of Riemann zeta values, which are real numbers first considered by Euler. It is known that there are many linear relations among these values with rational coefficients. Hoffman [Multiple harmonic series, Pacific J. Math.152 (1992) 275–290] gives a class of relations among multiple zeta values, which is called Hoffman's relation. In this paper, we show the corresponding relation for multiple zeta-star values by using partial-fractions expansion as Hoffman did.
Hyperthermia increases interleukin-6 in mouse skeletal muscle
Authors: Welc Steven S. , Phillips Neil A. , Oca-Cossio Jose , Wallet Shannon M. , Chen Daniel L. , Clanton Thomas L.
Published: June 2012

Skeletal muscles produce and contribute to circulating levels of IL-6 during exercise. However, when core temperature is reduced, the response is attenuated. Therefore, we hypothesized that hyperthermia may be an important and independent stimulus for muscle IL-6. In cultured C2C12 myotubes, hyperthermia (42°C) increased IL-6 gene expression 14-fold after 1 h and 35-fold after 5 h of 37°C recovery; whereas exposure to 41°C resulted in a 2.6-fold elevation at 1 h. IL-6 protein was secreted and significantly elevated in the cell supernatant. Similar but reduced responses to heat were seen in C2C12 myoblasts. Isolated soleus muscles from mice, exposed ex vivo to 41°C for 1 h, yielded similar IL-6 gene responses (>3-fold) but without a significant effect on protein release. When whole animals were exposed to passive hyperthermia, such that core temperature increased to 42.4°C, IL-6 mRNA in soleus increased 5.4-fold compared with time matched controls. Interestingly, TNF-α gene expression was routinely suppressed at all levels of hyperthermia (40.5–42°C) in the isolated models, but TNF-α was elevated (4.2-fold) in the soleus taken from intact mice exposed, in vivo, to hyperthermia. Muscle HSP72 mRNA increased as a function of the level of hyperthermia, and IL-6 mRNA responses increased proportionally with HSP72. In cultured C2C12 myotubes, when heat shock factor was pharmacologically blocked with KNK437, both HSP72 and IL-6 mRNA elevations, induced by heat, were suppressed. These findings implicate skeletal muscle as a “heat stress sensor” at physiologically relevant hyperthermia, responding with a programmed cytokine expression pattern characterized by elevated IL-6.
Identification of atrogin-1-targeted proteins during the myostatin-induced skeletal muscle wasting
Authors: Lokireddy Sudarsanareddy , Wijesoma Isuru Wijerupage , Sze Siu Kwan , McFarlane Craig , Kambadur Ravi , Sharma Mridula
Published: June 2012

Atrogin-1, a muscle-specific E3 ligase, targets MyoD for degradation through the ubiquitin-proteasome-mediated system. Myostatin, a member of the transforming growth factor-β superfamily, potently inhibits myogenesis by lowering MyoD levels. While atrogin-1 is upregulated by myostatin, it is currently unknown whether atrogin-1 plays a role in mediating myostatin signaling to regulate myogenesis. In this report, we have confirmed that atrogin-1 increasingly interacts with MyoD upon recombinant human myostatin (hMstn) treatment. The absence of atrogin-1, however, led to elevated MyoD levels and permitted the differentiation of atrogin-1−/− primary myoblast cultures despite the presence of exogenous myostatin. Furthermore, inactivation of atrogin-1 rescued myoblasts from growth inhibition by hMstn. Therefore, these results highlight the central role of atrogin-1 in regulating myostatin signaling during myogenesis. Currently, there are only two known targets of atrogin-1. Thus, we next characterized the associated proteins of atrogin-1 in control and hMstn-treated C2C12 cell cultures by stably expressing tagged atrogin-1 in myoblasts and myotubes, and sequencing the coimmunoprecipitated proteome. We found that atrogin-1 putatively interacts with sarcomeric proteins, transcriptional factors, metabolic enzymes, components of translation, and spliceosome formation. In addition, we also identified that desmin and vimentin, two components of the intermediate filament in muscle, directly interacted with and were degraded by atrogin-1 in response to hMstn. In summary, the muscle wasting effects of the myostatin-atrogin-1 axis are not only limited to the degradation of MyoD and eukaryotic translation initiation factor 3 subunit f, but also encompass several proteins that are involved in a wide variety of cellular activities in the muscle.
Ischemic pre- and postconditioning has pronounced effects on gene expression profiles in the rat liver after ischemia/reperfusion
Authors: Knudsen Anders Riegels , Kannerup Anne-Sofie , Dich Rune , Funch-Jensen Peter , Grønbæk Henning , Kruhøffer Mogens , Mortensen Frank Viborg
Published: June 2012

Ischemic pre (IPC)- and postconditioning (IPO) protect the liver against ischemia/reperfusion injuries (IRI). Conditioning involves several different trigger factors, mediators, and effectors, many of which are affected during the early phase of reperfusion, ultimately resulting in decreased liver injuries. The aim of the present study was to investigate the genomic response induced by IPC and IPO in ischemia/reperfusion-damaged rat liver biopsies. Forty-eight male Wistar rats were divided into five groups: sham ( n = 8), IRI ( n = 10), IPC ( n = 10), IPO ( n = 10), and IPC + IPO ( n = 10). The rat livers were subjected to 30 min of ischemia. Liver biopsies and blood samples were taken after 30 min of reperfusion. The biopsies were analyzed using cDNA microarrays with validation by quantitative RT-PCR. The significance analysis of microarray was used to identify genes with changed expression levels. A comparison analysis of the intervention groups showed a highly increased number of genes, with significantly different expression in the conditioned groups compared with the IRI group. A total of 172 genes were identified as the most highly affected, and these genes showed similar patterns with regard to the up- and downregulated expression levels within the conditioned groups. Pathway analysis of the 172 genes identified four networks that were involved in increased gene expression, cellular growth, and proliferation. In conclusion, the present study demonstrated that IPC, IPO, and IPC + IPO had pronounced effects on the expression levels of a large number of genes during early reperfusion. IPC, IPO, and IPC + IPO seem to mediate their protective effects by regulating the same genes and genetic networks. These identified networks are known to be involved in maintaining cellular homeostasis.
Gluconeogenesis is associated with high rates of tricarboxylic acid and pyruvate cycling in fasting northern elephant seals
Authors: Champagne Cory D. , Houser Dorian S. , Fowler Melinda A. , Costa Daniel P. , Crocker Daniel E.
Published: June 2012

Animals that endure prolonged periods of food deprivation preserve vital organ function by sparing protein from catabolism. Much of this protein sparing is achieved by reducing metabolic rate and suppressing gluconeogenesis while fasting. Northern elephant seals ( Mirounga angustirostris) endure prolonged fasts of up to 3 mo at multiple life stages. During these fasts, elephant seals maintain high levels of activity and energy expenditure associated with breeding, reproduction, lactation, and development while maintaining rates of glucose production typical of a postabsorptive mammal. Therefore, we investigated how fasting elephant seals meet the requirements of glucose-dependent tissues while suppressing protein catabolism by measuring the contribution of glycogenolysis, glycerol, and phosphoenolpyruvate (PEP) to endogenous glucose production (EGP) during their natural 2-mo postweaning fast. Additionally, pathway flux rates associated with the tricarboxylic acid (TCA) cycle were measured specifically, flux through phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate cycling. The rate of glucose production decreased during the fast (F1,13= 5.7, P = 0.04) but remained similar to that of postabsorptive mammals. The fractional contributions of glycogen, glycerol, and PEP did not change with fasting; PEP was the primary gluconeogenic precursor and accounted for ∼95% of EGP. This large contribution of PEP to glucose production occurred without substantial protein loss. Fluxes through the TCA cycle, PEPCK, and pyruvate cycling were higher than reported in other species and were the most energetically costly component of hepatic carbohydrate metabolism. The active pyruvate recycling fluxes detected in elephant seals may serve to rectify gluconeogeneic PEP production during restricted anaplerotic inflow in these fasting-adapted animals.
Cystogenesis and elongated primary cilia in Tsc1-deficient distal convoluted tubules
Authors: Armour Eric A. , Carson Robert P. , Ess Kevin C.
Published: June 2012

Tuberous sclerosis complex (TSC) is a multiorgan hamartomatous disease caused by loss of function mutations of either the TSC1 or TSC2 genes. Neurological symptoms of TSC predominate in younger patients, but renal pathologies are a serious aspect of the disease in older children and adults. To study TSC pathogenesis in the kidney, we inactivated the mouse Tsc1 gene in the distal convoluted tubules (DCT). At young ages, Tsc1 conditional knockout (CKO) mice have enlarged kidneys and mild cystogenesis with increased mammalian target of rapamycin complex (mTORC)1 but decreased mTORC2 signaling. Treatment with the mTORC1 inhibitor rapamycin reduces kidney size and cystogenesis. Rapamycin withdrawal led to massive cystogenesis involving both distal as well as proximal tubules. To assess the contribution of decreased mTORC2 signaling in kidney pathogenesis, we also generated Rictor CKO mice. These animals did not have any detectable kidney pathology. Finally, we examined primary cilia in the DCT. Cilia were longer in Tsc1 CKO mice, and rapamycin treatment returned cilia length to normal. Rictor CKO mice had normal cilia in the DCT. Overall, our findings suggest that loss of the Tsc1 gene in the DCT is sufficient for renal cystogenesis. This cytogenesis appears to be mTORC1 but not mTORC2 dependent. Intriguingly, the mechanism may be cell autonomous as well as non-cell autonomous and possibly involves the length and function of primary cilia.
Loss of renal medullary endothelin B receptor function during salt deprivation is regulated by angiotensin II
Authors: Kittikulsuth Wararat , Pollock Jennifer S. , Pollock David M.
Published: June 2012

We have recently demonstrated that chronic infusion of exogenous ANG II, which induces blood pressure elevation, attenuates renal medullary endothelin B (ETB) receptor function in rats. Moreover, this was associated with a reduction of ETBreceptor expression in the renal inner medulla. The aim of this present work was to investigate the effect of a physiological increase in endogenous ANG II (low-salt diet) on the renal ET system, including ETBreceptor function. We hypothesized that endogenous ANG II reduces renal medullary ETBreceptor function during low-salt intake. Rats were placed on a low-salt diet (0.01–0.02% NaCl) for 2 wk to allow an increase in endogenous ANG II. In rats on normal-salt chow, the stimulation of renal medullary ETBreceptor by ETBreceptor agonist sarafotoxin 6c (S6c) causes an increase in water (3.6 ± 0.4 from baseline vs. 10.5 ± 1.3 μl/min following S6c infusion; P < 0.05) and sodium excretion (0.38 ± 0.06 vs. 1.23 ± 0.17 μmol/min; P < 0.05). The low-salt diet reduced the ETB-dependent diuresis (4.5 ± 0.5 vs. 6.1 ± 0.9 μl/min) and natriuresis (0.40 ± 0.11 vs. 0.46 ± 0.12 μmol/min) in response to acute intramedullary infusion of S6c. Chronic treatment with candesartan restored renal medullary ETBreceptor function; urine flow was 7.1 ± 0.9 vs. 15.9 ± 1.7 μl/min ( P < 0.05), and sodium excretion was 0.4 ± 0.1 vs. 1.1 ± 0.1 μmol/min ( P < 0.05) before and after intramedullary S6c infusion, respectively. Receptor binding assays determined that the sodium-depleted diet resulted in a similar level of ETBreceptor binding in renal inner medulla compared with rats on a normal-salt diet. Candesartan reduced renal inner medullary ETBreceptor binding (1,414 ± 95 vs. 862 ± 50 fmol/mg; P < 0.05). We conclude that endogenous ANG II attenuates renal medullary ETBreceptor function to conserve sodium during salt deprivation independently of receptor expression.
Membrane-associated aquaporin-1 facilitates osmotically driven water flux across the basolateral membrane of the thick ascending limb
Authors: Cabral Pablo D. , Herrera Marcela
Published: June 2012

The thick ascending limb of the loop of Henle (TAL) reabsorbs ∼30% of filtered NaCl but is impermeable to water. The observation that little water traverses the TAL indicates an absence of water channels at the apical membrane. Yet TAL cells swell when peritubular osmolality decreases indicating that water channels must be present in the basolateral side. Consequently, we hypothesized that the water channel aquaporin-1 (AQP1) facilitates water flux across the basolateral membrane of TALs. Western blotting revealed AQP1 expression in microdissected rat and mouse TALs. Double immunofluorescence showed that 95 ± 2% of tubules positive for the TAL-specific marker Tamm-Horsfall protein were also positive for AQP1 ( n = 6). RT-PCR was used to demonstrate presence of AQP1 mRNA and the TAL-specific marker NKCC2 in microdissected TALs. Cell surface biotinylation assays showed that 23 ± 3% of the total pool of AQP1 was present at the TAL basolateral membrane ( n = 7). To assess the functional importance of AQP1 in the basolateral membrane, we measured the rate of cell swelling initiated by decreasing peritubular osmolality as an indicator of water flux in microdissected TALs. Water flux was decreased by ∼50% in Aqp1 knockout mice compared with wild-types (4.0 ± 0.8 vs. 8.9 ± 1.7 fluorescent U/s, P < 0.02; n = 7). Furthermore, arginine vasopressin increased TAL AQP1 expression by 135 ± 17% (glycosylated) and 41 ± 11% (nonglycosylated; P < 0.01; n =5). We conclude that 1) the TAL expresses AQP1, 2) ∼23% of the total pool of AQP1 is localized to the basolateral membrane, 3) AQP1 mediates a significant portion of basolateral water flux, and 4) AQP1 is upregulated in TALs of rats infused with dDAVP. AQP1 could play an important role in regulation of TAL cell volume during changes in interstitial osmolality, such as during a high-salt diet or water deprivation.
Integration of cortical and pallidal inputs in the basal ganglia-recipient thalamus of singing birds
Authors: Goldberg Jesse H. , Farries Michael A. , Fee Michale S.
Published: June 2012

The basal ganglia-recipient thalamus receives inhibitory inputs from the pallidum and excitatory inputs from cortex, but it is unclear how these inputs interact during behavior. We recorded simultaneously from thalamic neurons and their putative synaptically connected pallidal inputs in singing zebra finches. We find, first, that each pallidal spike produces an extremely brief (∼5 ms) pulse of inhibition that completely suppresses thalamic spiking. As a result, thalamic spikes are entrained to pallidal spikes with submillisecond precision. Second, we find that the number of thalamic spikes that discharge within a single pallidal interspike interval (ISI) depends linearly on the duration of that interval but does not depend on pallidal activity prior to the interval. In a detailed biophysical model, our results were not easily explained by the postinhibitory “rebound” mechanism previously observed in anesthetized birds and in brain slices, nor could most of our data be characterized as “gating” of excitatory transmission by inhibitory pallidal input. Instead, we propose a novel “entrainment” mechanism of pallidothalamic transmission that highlights the importance of an excitatory conductance that drives spiking, interacting with brief pulses of pallidal inhibition. Building on our recent finding that cortical inputs can drive syllable-locked rate modulations in thalamic neurons during singing, we report here that excitatory inputs affect thalamic spiking in two ways: by shortening the latency of a thalamic spike after a pallidal spike and by increasing thalamic firing rates within individual pallidal ISIs. We present a unifying biophysical model that can reproduce all known modes of pallidothalamic transmission—rebound, gating, and entrainment—depending on the amount of excitation the thalamic neuron receives.
The interaction of postural and voluntary strategies for stability in Parkinson's disease
Authors: de Lima-Pardini Andrea C. , Papegaaij Selma , Cohen Rajal G. , Teixeira Luis A. , Smith Beth A. , Horak Fay B.
Published: June 2012

This study assessed the effects of stability constraints of a voluntary task on postural responses to an external perturbation in subjects with Parkinson's disease (PD) and healthy elderly participants. Eleven PD subjects and twelve control subjects were perturbed with backward surface translations while standing and performing two versions of a voluntary task: holding a tray with a cylinder placed with the flat side down [low constraint (LC)] or with the rolling, round side down [high constraint (HC)]. Participants performed alternating blocks of LC and HC trials. PD participants accomplished the voluntary task as well as control subjects, showing slower tray velocity in the HC condition compared with the LC condition. However, the latency of postural responses was longer in the HC condition only for control subjects. Control subjects presented different patterns of hip-shoulder coordination as a function of task constraint, whereas PD subjects had a relatively invariant pattern. Initiating the experiment with the HC task led to 1) decreased postural stability in PD subjects only and 2) reduced peak hip flexion in control subjects only. These results suggest that PD impairs the capacity to adapt postural responses to constraints imposed by a voluntary task.
Force encoding in stick insect legs delineates a reference frame for motor control
Authors: Zill Sasha N. , Schmitz Josef , Chaudhry Sumaiya , Büschges Ansgar
Published: June 2012

The regulation of forces is integral to motor control. However, it is unclear how information from sense organs that detect forces at individual muscles or joints is incorporated into a frame of reference for motor control. Campaniform sensilla are receptors that monitor forces by cuticular strains. We studied how loads and muscle forces are encoded by trochanteral campaniform sensilla in stick insects. Forces were applied to the middle leg to emulate loading and/or muscle contractions. Selective sensory ablations limited activities recorded in the main leg nerve to specific receptor groups. The trochanteral campaniform sensilla consist of four discrete groups. We found that the dorsal groups (Groups 3 and 4) encoded force increases and decreases in the plane of movement of the coxo-trochanteral joint. Group 3 receptors discharged to increases in dorsal loading and decreases in ventral load. Group 4 showed the reverse directional sensitivities. Vigorous, directional responses also occurred to contractions of the trochanteral depressor muscle and to forces applied at the muscle insertion. All sensory discharges encoded the amplitude and rate of loading or muscle force. Stimulation of the receptors produced reflex effects in the depressor motoneurons that could reverse in sign during active movements. These data, in conjunction with findings of previous studies, support a model in which the trochanteral receptors function as an array that can detect forces in all directions relative to the intrinsic plane of leg movement. The array could provide requisite information about forces and simplify the control and adaptation of posture and walking.
Skin incision-induced receptive field responses of mechanosensitive peripheral neurons are developmentally regulated in the rat
Authors: Boada M. Danilo , Gutierrez Silvia , Giffear Kelly , Eisenach James C. , Ririe Douglas G.
Published: June 2012

Maturation of the nervous system results in changes in both central and peripheral processing. To better understand responses to injury in the young, developmental differences in the acute response to incision were investigated in both tactile and nociceptive myelinated peripheral mechanosensitive afferent neurons in vivo. Neuronal intrasomal recordings were performed in juvenile and infant rats in 34 L5 dorsal root ganglia, and each neuron was phenotypically defined. Neurons had a mechanosensitive receptive field in the glabrous skin on the plantar surface of the hind paw, which was characterized at baseline and for up to 45 min after incision. Fundamental maturational differences in the effect of incision were clear: in high-threshold nociceptive mechanoreceptors, the mechanical threshold decreased immediately and the receptive field size increased rapidly in juvenile rats but not in infant rats. Additionally, a divergence in changes in the instantaneous response frequency of tactile afferents occurred between the two ages. These differences may help explain maturational differences in responses to peripheral injury and suggest that differences in central nervous system responses may be partially mitigated by spatially confined and frequency-dependent differences resulting from tactile and nociceptive mechanosensitive input.
Sphingosine 1-phosphate receptor 2 antagonist JTE-013 increases the excitability of sensory neurons independently of the receptor
Authors: Li Chao , Chi Xian Xuan , Xie Wenrui , Strong J. A. , Zhang J.-M. , Nicol G. D.
Published: June 2012

Previously we demonstrated that sphingosine 1-phosphate receptor 1 (S1PR1) played a prominent, but not exclusive, role in enhancing the excitability of small-diameter sensory neurons, suggesting that other S1PRs can modulate neuronal excitability. To examine the potential role of S1PR2in regulating neuronal excitability we used the established selective antagonist of S1PR2, JTE-013. Here we report that exposure to JTE-013 alone produced a significant increase in excitability in a time- and concentration-dependent manner in 70–80% of recorded neurons. Internal perfusion of sensory neurons with guanosine 5′- O-(2-thiodiphosphate) (GDP-β-S) via the recording pipette inhibited the sensitization produced by JTE-013 as well as prostaglandin E2. Pretreatment with pertussis toxin or the selective S1PR1antagonist W146 blocked the sensitization produced by JTE-013. These results indicate that JTE-013 might act as an agonist at other G protein-coupled receptors. In neurons that were sensitized by JTE-013, single-cell RT-PCR studies demonstrated that these neurons did not express the mRNA for S1PR2. In behavioral studies, injection of JTE-013 into the rat's hindpaw produced a significant increase in the mechanical sensitivity in the ipsilateral, but not contralateral, paw. Injection of JTE-013 did not affect the withdrawal latency to thermal stimulation. Thus JTE-013 augments neuronal excitability independently of S1PR2by unknown mechanisms that may involve activation of other G protein-coupled receptors such as S1PR1. Clearly, further studies are warranted to establish the causal nature of this increased sensitivity, and future studies of neuronal function using JTE-013 should be interpreted with caution.
Absence of effects of contralateral group I muscle afferents on presynaptic inhibition of Ia terminals in humans and cats
Authors: Mezzarane Rinaldo André , Kohn André Fabio , Couto-Roldan Erika , Martinez Lourdes , Flores Amira , Manjarrez Elias
Published: June 2012

Crossed effects from group I afferents on reflex excitability and their mechanisms of action are not yet well understood. The current view is that the influence is weak and takes place indirectly via oligosynaptic pathways. We examined possible contralateral effects from group I afferents on presynaptic inhibition of Ia terminals in humans and cats. In resting and seated human subjects the soleus (SO) H-reflex was conditioned by an electrical stimulus to the ipsilateral common peroneal nerve (CPN) to assess the level of presynaptic inhibition (PSI_control). A brief conditioning vibratory stimulus was applied to the triceps surae tendon at the contralateral side (to activate preferentially Ia muscle afferents). The amplitude of the resulting H-reflex response (PSI_conditioned) was compared to the H-reflex under PSI_control, i.e., without the vibration. The interstimulus interval between the brief vibratory stimulus and the electrical shock to the CPN was −60 to 60 ms. The H-reflex conditioned by both stimuli did not differ from that conditioned exclusively by the ipsilateral CPN stimulation. In anesthetized cats, bilateral monosynaptic reflexes (MSRs) in the left and right L7 ventral roots were recorded simultaneously. Conditioning stimulation applied to the contralateral group I posterior biceps and semitendinosus (PBSt) afferents at different time intervals (0–120 ms) did not have an effect on the ipsilateral gastrocnemius/soleus (GS) MSR. An additional experimental paradigm in the cat using contralateral tendon vibration, similar to that conducted in humans, was also performed. No significant differences between GS-MSRs conditioned by ipsilateral PBSt stimulus alone and those conditioned by both ipsilateral PBSt stimulus and contralateral tendon vibration were detected. The present results strongly suggest an absence of effects from contralateral group I fibers on the presynaptic mechanism of MSR modulation in relaxed humans and anesthetized cats.
A-current and type I/type II transition determine collective spiking from common input
Authors: Barreiro Andrea K. , Thilo Evan L. , Shea-Brown Eric
Published: June 2012

The mechanisms and impact of correlated, or synchronous, firing among pairs and groups of neurons are under intense investigation throughout the nervous system. A ubiquitous circuit feature that can give rise to such correlations consists of overlapping, or common, inputs to pairs and populations of cells, leading to common spike train responses. Here, we use computational tools to study how the transfer of common input currents into common spike outputs is modulated by the physiology of the recipient cells. We focus on a key conductance, gA, for the A-type potassium current, which drives neurons between “type II” excitability (low gA), and “type I” excitability (high gA). Regardless of gA, cells transform common input fluctuations into a tendency to spike nearly simultaneously. However, this process is more pronounced at low gA values. Thus, for a given level of common input, type II neurons produce spikes that are relatively more correlated over short time scales. Over long time scales, the trend reverses, with type II neurons producing relatively less correlated spike trains. This is because these cells' increased tendency for simultaneous spiking is balanced by an anticorrelation of spikes at larger time lags. These findings extend and interpret prior findings for phase oscillators to conductance-based neuron models that cover both oscillatory (superthreshold) and subthreshold firing regimes. We demonstrate a novel implication for neural signal processing: downstream cells with long time constants are selectively driven by type I cell populations upstream and those with short time constants by type II cell populations. Our results are established via high-throughput numerical simulations and explained via the cells' filtering properties and nonlinear dynamics.
Muscle spindle responses to horizontal support surface perturbation in the anesthetized cat: insights into the role of autogenic feedback in whole body postural control
Authors: Honeycutt Claire F. , Nardelli Paul , Cope Timothy C. , Nichols T. Richard
Published: June 2012

Intact cats and humans respond to support surface perturbations with broadly tuned, directionally sensitive muscle activation. These muscle responses are further sensitive to initial stance widths (distance between feet) and perturbation velocity. The sensory origins driving these responses are not known, and conflicting hypotheses are prevalent in the literature. We hypothesize that the direction-, stance-width-, and velocity-sensitive muscle response during support surface perturbations is driven largely by rapid autogenic proprioceptive pathways. The primary objective of this study was to obtain direct evidence for our hypothesis by establishing that muscle spindle receptors in the intact limb can provide appropriate information to drive the muscle response to whole body postural perturbations. Our second objective was to determine if spindle recordings from the intact limb generate the heightened sensitivity to small perturbations that has been reported in isolated muscle experiments. Maintenance of this heightened sensitivity would indicate that muscle spindles are highly proficient at detecting even small disturbances, suggesting they can provide efficient feedback about changing postural conditions. We performed intraaxonal recordings from muscle spindles in anesthetized cats during horizontal, hindlimb perturbations. We indeed found that muscle spindle afferents in the intact limb generate broadly tuned but directionally sensitive activation patterns. These afferents were also sensitive to initial stance widths and perturbation velocities. Finally, we found that afferents in the intact limb have heightened sensitivity to small perturbations. We conclude that muscle spindle afferents provide an array of important information about biomechanics and perturbation characteristics highlighting their potential importance in generating appropriate muscular response during a postural disturbance.
Shape encoding consistency across colors in primate V4
Authors: Bushnell Brittany N. , Pasupathy Anitha
Published: June 2012

Neurons in primate cortical area V4 are sensitive to the form and color of visual stimuli. To determine whether form selectivity remains consistent across colors, we studied the responses of single V4 neurons in awake monkeys to a set of two-dimensional shapes presented in two different colors. For each neuron, we chose two colors that were visually distinct and that evoked reliable and different responses. Across neurons, the correlation coefficient between responses in the two colors ranged from −0.03 to 0.93 (median 0.54). Neurons with highly consistent shape responses, i.e., high correlation coefficients, showed greater dispersion in their responses to the different shapes, i.e., greater shape selectivity, and also tended to have less eccentric receptive field locations; among shape-selective neurons, shape consistency ranged from 0.16 to 0.93 (median 0.63). Consistency of shape responses was independent of the physical difference between the stimulus colors used and the strength of neuronal color tuning. Finally, we found that our measurement of shape response consistency was strongly influenced by the number of stimulus repeats: consistency estimates based on fewer than 10 repeats were substantially underestimated. In conclusion, our results suggest that neurons that are likely to contribute to shape perception and discrimination exhibit shape responses that are largely consistent across colors, facilitating the use of simpler algorithms for decoding shape information from V4 neuronal populations.
Imperforate Hymen Causing Bilateral Hydroureteronephrosis in an Infant with Bicornuate Uterus
Authors: Eksioglu Ayse Secil , Maden Hasim Ata , Cinar Gokce , Tasci Yildiz Yasemin
Published: June 2012

A rare case of imperforate hymen associated with bicornuate uterus in an infant is presented as a cause of bilateral hydroureteronephrosis and pelvic mass in infancy. The importance of postoperative radiologic evaluation for diagnosis of accompanying uterine abnormalities is introduced. A 8-month-old girl with restlessness and intermittent fever was brought to the daily outpatient clinic by her parents. Ultrasound exam showed bilateral grade 4 hydroureteronephrosis and a large cystic pelvic mass. Magnetic resonance scan of the pelvis revealed marked hematocolpos. A cruciate incision was made over the hymen under general anesthesia. During a 6-month followup gradual resolution of bilateral hydroureteronephrosis was documented. Although the details of the uterine anomaly were obscured in preoperative imaging, postoperative US and MR demonstrated bicornuate uterus. Postoperative pelvic radiologic examination is highly recommended to verify the resolution of hematocolpos and to screen for any concomitant anomalies that can have long-term clinical significance.
Useful Solutions for Plane Wave Diffraction by Dielectric Slabs and Wedges
Authors: Gennarelli Gianluca , Riccio Giovanni
Published: June 2012

This work presents an overview of available uniform asymptotic physical optics solutions for evaluating the plane wave diffraction by some canonical geometries of large interest: dielectric slabs and wedges. Such solutions are based on a physical optics approximation of the electric and magnetic equivalent surface currents in the involved scattering integrals. The resulting diffraction coefficients are expressed in terms of the geometrical optics response of the considered structure and the standard transition function of the Uniform Geometrical Theory of Diffraction. Numerical tests and comparisons make evident the effectiveness and reliability of the presented solutions.
Effect of Zinc on Efficacy of Iron Supplementation in Improving Iron and Zinc Status in Women
Authors: Nguyen Phuong , Grajeda Ruben , Melgar Paul , Marcinkevage Jessica , Flores Rafael , Ramakrishnan Usha , Martorell Reynaldo
Published: June 2012

Iron and zinc may interact in micronutrient supplements and thereby decrease efficacy. We investigated interactive effects of combined zinc and iron supplementation in a randomized controlled trial conducted in 459 Guatemalan women. Four groups were supplemented for 12 weeks: (1) weekly iron and folic acid (IFA); (2) weekly IFA and 30 mg zinc; (3) daily IFA; (4) daily IFA and 15 mg zinc. Effects were assessed by generalized linear regression. Baseline hemoglobin (Hb) concentration was137.4±15.5 g/L, 13% were anemic and 54% had zinc deficiency. Hb cconcentrations were similar by supplement type, but Hb concentrations improved significantly in anemic women at baseline (increase of 21.8 g/L). Mean percentage changes in serum ferritin were significantly higher in daily compared to weekly supplemented groups (86% versus 32%). The addition of zinc to IFA supplements had no significant impact on iron or zinc status. In conclusion, adding zinc to IFA supplements did not modify efficacy on iron status or improve zinc status, but daily supplementation was more efficacious than weekly in improving iron stores.
The Painful Side of Trap and Fixed Net Fisheries: Chronic Entanglement of Large Whales
Authors: Moore Michael J. , van der Hoop Julie M.
Published: June 2012

Concern over the well-being of marine mammals at sea has focused on intentional harvests, both in terms of individual welfare and population sustainability. Unintentional mortalities from fishing gear entanglement are primarily seen as a risk to population viability. Additionally, larger whales breaking free of, and subsequently carrying, fixed trap and net gear are subject to a very slow demise, averaging 6 months in the case of the North Atlantic right whale (Eubalaena glacialis). Chronic cases can involve impaired foraging, increased drag, infection, hemorrhage, and severe tissue damage. The individual suffering of these cases appears to be extreme. Thus management measures should go beyond legally mandated conservation measures to include avoidance of such scenarios. Seafood consumers could succeed, where laws have failed, to demand fishing practices that do not kill whales in this manner. The effective absence of such demands would seem to reflect the cryptic nature of these cases to most consumers.
Dermatitis Herpetiformis: From the Genetics to the Development of Skin Lesions
Authors: Bonciani Diletta , Verdelli Alice , Bonciolini Veronica , D'Errico Antonietta , Antiga Emiliano , Fabbri Paolo , Caproni Marzia
Published: June 2012

Dermatitis herpetiformis (DH) is a rare autoimmune disease linked to gluten sensitivity with a chronic-relapsing course. It is currently considered to be the specific cutaneous manifestation of celiac disease (CD). Both conditions are mediated by the IgA class of autoantibodies, and the diagnosis of DH is dependent on the detection of granular deposits of IgA in the skin. There is an underlying genetic predisposition to the development of DH, but environmental factors are also important. This paper describes these different factors and discusses the known mechanism that lead to the development of skin lesions.
Intersphincteric Resection for Low Rectal Cancer: An Overview
Authors: Spanos Constantine P.
Published: June 2012

The treatment of rectal cancer has evolved from being solely a surgical endeavor to a multidisciplinary practice. Despite the improvement in outcomes conferred by the addition of chemoradiation therapy to rectal cancer treatment, advances in surgical technique have significantly increased rates of sphincter preservation and the avoidance of a permanent stoma. In recent years, intersphincteric resection for low rectal cancer has been offered and performed in patients as an alternative to abdominoperineal resection. An overview of this procedure, including indications, oncological and functional results based on current literature, is presented herein.
Homoclinic Orbits for Second‐Order Hamiltonian Systems with Some Twist Condition
Authors: Wang Qi , Zhang Qingye
Published: June 2012

We study the existence and multiplicity of homoclinic orbits for second‐order Hamiltonian systems , where L(t) is unnecessarily positive definite for all t ∈ ℝ, and ∇qW(t, q) is of at most linear growth and satisfies some twist condition between the origin and the infinity.
Minocycline Decreases Liver Injury after Hemorrhagic Shock and Resuscitation in Mice
Authors: Czerny Christoph , Kholmukhamedov Andaleb , Theruvath Tom P. , Maldonado Eduardo N. , Ramshesh Venkat K. , Lehnert Mark , Marzi Ingo , Zhong Zhi , Lemasters John J.
Published: June 2012

Patients that survive hemorrhage and resuscitation (H/R) may develop a systemic inflammatory response syndrome (SIRS) that leads to dysfunction of vital organs (multiple organ dysfunction syndrome, MODS). SIRS and MODS may involve mitochondrial dysfunction. Under pentobarbital anesthesia, C57BL6 mice were hemorrhaged to 30 mm Hg for 3 h and then resuscitated with shed blood plus half the volume of lactated Ringer’s solution containing minocycline, tetracycline (both 10 mg/kg body weight) or vehicle. Serum alanine aminotransferase (ALT), necrosis, apoptosis and oxidative stress were assessed 6 h after resuscitation. Mitochondrial polarization was assessed by intravital microscopy. After H/R with vehicle or tetracycline, ALT increased to 4538 U/L and 3999 U/L, respectively, which minocycline decreased to 1763 U/L (P<0.01). Necrosis and TUNEL also decreased from 24.5% and 17.7 cells/field, respectively, after vehicle to 8.3% and 8.7 cells/field after minocycline. Tetracycline failed to decrease necrosis (23.3%) but decreased apoptosis to 9 cells/field (P<0.05). Minocycline and tetracycline also decreased caspase-3 activity in liver homogenates. Minocycline but not tetracycline decreased lipid peroxidation after resuscitation by 70% (P<0.05). Intravital microscopy showed that minocycline preserved mitochondrial polarization after H/R (P<0.05). In conclusion, minocycline decreases liver injury and oxidative stress after H/R by preventing mitochondrial dysfunction.
Control of the False Discovery Proportion for Independently Tested Null Hypotheses
Authors: Ge Yongchao , Li Xiaochun
Published: June 2012

Consider the multiple testing problem of testingmnull hypothesesH1,…,Hm, among whichm0hypotheses are truly null. Given theP-values for each hypothesis, the question of interest is how to combine theP-values to find out which hypotheses are false nulls and possibly to make a statistical inference onm0. Benjamini and Hochberg proposed a classical procedure that can control the false discovery rate (FDR). The FDR control is a little bit unsatisfactory in that it only concerns the expectation of the false discovery proportion (FDP). The control of the actual random variable FDP has recently drawn much attention. For any level1−α, this paper proposes a procedure to construct an upper prediction bound (UPB) for the FDP for a fixed rejection region. When1−α=50%, our procedure is very close to the classical Benjamini and Hochberg procedure. Simultaneous UPBs for all rejection regions' FDPs and the upper confidence bound for the unknownm0are presented consequently. This new proposed procedure works for finite samples and hence avoids the slow convergence problem of the asymptotic theory.
Study on Vibration Behavior of Doubly Clamped Silicon Nanowires by Molecular Dynamics
Authors: Yu H. , Zhang W. W. , Lei S. Y. , Lu L. B. , Sun C. , Huang Q. A.
Published: June 2012

The vibration behavior of doubly clamped silicon nanowires with square cross sections is studied by molecular dynamics method. Silicon nanowires have lengths ranging from 4.888 to 12.491 nm and cross sections ranging from 1.22 nm × 1.22 nm to 3.39 nm × 3.39 nm. The size dependence of the resonant frequency is studied in detail. The results show that the vibration behavior of Si nanowire is quite different from the macroscopic beam, and the resonant frequency is much higher than the result based on the continuum theory, but close to the theoretical result based on the semicontinuum approach. Surface reconstruction can strongly affect on vibration behavior. These results demonstrate that the classic theory may not be suitable for analysis of performances of nanostructures, and the conclusion of the study has a certain practical significance on related fields.
Investigation of the Energy Correlations of Spallation Neutrons by Monte Carlo Simulations
Authors: Szieberth Máté , Radócz Gábor
Published: June 2012

Earlier works have suggested that the energy correlations in a spallation source may influence the neutron noise measurements in an ADS. For the calculation of this effect not only the generally known and used one-particle spectrum is needed but also the so-called two particle spectrum, which describes also the energy correlations. Since measured data are not available for the energy correlation of the neutrons from a single spallation event, the physical models of the MCNPX code have been used to investigate the effect. The calculational model has been successfully validated with measurements of the number distribution of spallation neutrons. The simulated one- and two-particle energy distributions and spectra proved that the energy correlations exist and have an important effect in low multiplicity spallation events and in thin targets. On the other hand, for thick targets this effect appears negligible and the factorization of the two-particle spectrum seems an acceptable approximation. Further investigations are in hand to quantify the actual effect of the energy correlations on the neutron noise measurements.