235 research outputs found

    The circadian system alters thermoregulation depending on the time of day and feeding condition

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    The circadian rhythm of body temperature (Tb) is a well-known phenomenon. However, it is unknown how the circadian system affects thermoregulation. Food deprivation in mice induces a greater reduction of Tb particularly in the light phase. We examined the role of the clock gene and the suprachiasmatic nucleus (SCN) during induced hypothermia. At 20C with fasting, mice increased their metabolic heat production in the dark phase and maintained T~b~, whereas in the light phase, heat production was less, resulting in hypothermia. Under these conditions, neuronal activity in the SCN, assessed by cFos expression, increased only in the light phase. The differences between the phases in Clock mutant mice were less marked. The neural network between the SCN and paraventricular nucleus appeared to be important in hypothermia. These findings suggest that the circadian system per se is influenced by both the feeding condition and environmental temperature and that it modulates thermoregulation

    Circadian Body Temperature Rhythm and the Interaction with Energy State

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    We have revealed that circadian body temperature (Tb) rhythm is significantly influenced by fasting/fasting-related hormones. The effect of circadian mechanism and fasting/fasting-related hormones on thermoregulation was examined. Fasting decreases Tb during the light phase in rodents. For the regulation, the suprachiasmatic nucleus (SCN) and clock genes, such as Cry and Clock, are necessary. In addition, ghrelin and several hypothalamic nuclei, that is, the medial preoptic area, paraventricular nucleus (PVN), and arcuate nucleus (ARC), play a key role in the Tb rhythm. During the light phase, fasting and ghrelin affect the hypothalamic areas. The activity of the SCN increases and that of the ARC decreases. The SCN sends inhibitory signals to the PVN, which may result in a lower heat production in the interscapular brown adipose tissue (iBAT) and Tb. By contrast, during the dark phase, the activity of the SCN decreases and that of the ARC increases. The inhibitory signal from the SCN is less, and the PVN is activated. Heat production of the iBAT increases and Tb is maintained. There are functional and anatomical connections between the circadian and thermoregulation systems. The circadian system modulates thermoregulatory response to hypothermia and/or cold depending on time and feeding condition

    CP Violation in Three-Body Chargino Decays

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    CP violation in supersymmetry can give rise to rate asymmetries in the decays of supersymmetric particles. In this work we compute the rate asymmetries for the three-body chargino decays \tilde\chi^\pm_2 \to \tilde\chi^\pm_1 HH, \tilde\chi^\pm_2 \to \tilde\chi^\pm_1 ZZ, \tilde\chi^\pm_2 \to \tilde\chi^\pm_1 W^+ W^- and \tilde\chi^\pm_2 \to tilde\chi^\pm_1 ZH. Each of the decays contains contributions mediated by neutral Higgs bosons that can possibly go on shell. Such contributions receive a resonant enhancement; furthermore, the strong phases required for the CP asymmetries come from the widths of the exchanged Higgs bosons. Our results indicate that the rate asymmetries can be relatively large in some cases, while still respecting a number of important low-energy bounds such as those coming from B meson observables and electric dipole moments. For the parameters that we consider, rate asymmetries of order 10% are possible in some cases.Comment: 17 pages, 4 figures, published versio

    Growth suppression of ice crystal basal face in the presence of a moderate ice-binding protein does not confer hyperactivity

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    Ice-binding proteins (IBPs) affect ice crystal growth by attaching to crystal faces. We present the effects on the growth of an ice single crystal caused by an ice-binding protein from the sea ice microalga Fragilariopsis cylindrus (fcIBP) that is characterized by the widespread domain of unknown function 3494 (DUF3494) and known to cause a moderate freezing point depression (below 1 °C). By the application of interferometry, bright-field microscopy, and fluorescence microscopy, we observed that the fcIBP attaches to the basal faces of ice crystals, thereby inhibiting their growth in the c direction and resulting in an increase in the effective supercooling with increasing fcIBP concentration. In addition, we observed that the fcIBP attaches to prism faces and inhibits their growth. In the event that the effective supercooling is small and crystals are faceted, this process causes an emergence of prism faces and suppresses crystal growth in the a direction. When the effective supercooling is large and ice crystals have developed into a dendritic shape, the suppression of prism face growth results in thinner dendrite branches, and growth in the a direction is accelerated due to enhanced latent heat dissipation. Our observations clearly indicate that the fcIBP occupies a separate position in the classification of IBPs due to the fact that it suppresses the growth of basal faces, despite its moderate freezing point depression

    Step-bunching instability of growing interfaces between ice and supercooled water

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    金沢大学学術メディア創成センターIce-crystal growth in supercooled water is one of the most familiar examples of phase-transition dynamics, playing essential roles in various natural phenomena on Earth. Despite its fundamental importance, the microscopic view at the elementary step level remains elusive. Here, using an advanced optical microscope, we find self-organization of elementary steps during ice-crystal growth, called step-bunching instability (SBI), driven by the competition between step dynamics, interfacial stiffness, and latent heat diffusions. We also find that the SBI transiently induces screw dislocations and resulting spiral growth in the late stage of the growth process. Furthermore, quantitative observations with a two-beam interferometer allow us to obtain insights into the relative importance of the various mechanisms of the step–step interactions. Our finding offers a significant clue to understanding the general mechanism of melt growth beyond ice-crystal growth, inseparably involving several broad research fields, including cryobiological, geophysical, and material branches

    Long-term survival in a case of hepatocellular carcinoma.

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    A patient with an unresectable hepatocellular carcinoma (HCC) who survived without active treatment 3 years and 8 months after histological diagnosis is described. The size of the liver, which was already quite huge at the time of diagnosis, changed little during the entire clinical observation. However, 2 months before death, his condition deteriorated rapidly following gastrointestinal bleeding due to the direct invasion of the stomach by HCC. A critical reason for the unusually long-term survival of the patient may stem from the facts that a well-differentiated and bile-producing HCC was extent in most encapsulated-tumor tissues and that liver cirrhosis was not present.</p

    Gait-Assist Wearable Robot Using Interactive Rhythmic Stimulation to the Upper Limbs

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    Many power-assist wearable exoskeletons have been developed to provide walking support and gait rehabilitation for elderly subjects and gait-disorder patients. Most designers have focused on a direct power-assist to the wearer's lower limbs. However, gait is a coordinated rhythmic movement of four limbs controlled intrinsically by central pattern generators, with the upper limbs playing an important role in walking. Maintaining a normal gait can become difficult as a person ages, because of decreases in limb coordination, stride length, and gait speed. It is known that coordination mechanisms can be governed by the principle of mutual entrainment, in which synchronization develops through the interaction between nonlinear phase oscillators in biological systems. This principle led us to hypothesize that interactive rhythmic stimulation to upper-limb movements might compensate for the age-related decline in coordination, thereby improving the gait in the elderly. To investigate this hypothesis, we developed a gait-assist wearable exoskeleton that employs interactive rhythmic stimulation to the upper limbs. In particular, we investigated the effects on spatial (i.e., hip-swing amplitude) and temporal (i.e., hip-swing period) gait parameters by conducting walking experiments with 12 healthy elderly subjects under one control condition and five upper-limb-assist conditions, where the output motor torque was applied at five different upper-limb swing positions. The results showed a statistically significant increase in the mean hip-swing amplitude, with a mean increment of about 7% between the control and upper-limb-assist conditions. They also showed a statistically significant decrease in the mean hip-swing period, with a mean decrement of about 2.3% between the control and one of the upper-limb-assist conditions. Although the increase in the hip-swing amplitude and the decrease in the hip-swing period were both small, the results indicate the possibility that interactive rhythmic stimulation to the upper limbs might have a positive effect on the gait of the elderly

    Insulin binding to erythrocytes in diabetes mellitus.

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    Insulin binding to erythrocytes was studied in diabetic patients. Insulin binding was lower in untreated diabetics and diabetic patients treated with diet or insulin than in normal subjects. Binding variation was mainly due to decreased binding site concentration in untreated and insulin-treated patients, and to lowered insulin binding site affinity in diet-treated patients. Several patients treated with hypoglycemic agents showed higher insulin binding due to increased binding site concentration. Insulin binding to erythrocytes may not always reflect the insulin binding status of insulin sensitive tissues.</p

    Recognition and behavioral assessment of acute pain in cats: literature review

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    Embora a dor seja considerada o quarto sinal vital e uma das manifestações mais comumente encontradas na prática médica veterinária dos animais domésticos, seu tratamento ainda é inadequado. A dor aguda pós-operatória tem suscitado grande interesse por seu potencial risco de cronificação caso não adequadamente tratada, podendo piorar a recuperação e a qualidade de vida do paciente. O gato é uma das espécies domésticas menos estudadas no que diz respeito ao reconhecimento e controle da dor, e algumas das dificuldades residem na avaliação e na percepção da dor. O consenso sobre os sinais comportamentais da dor nesta espécie publicado em fevereiro de 2016 considerou alguns sinais como confiáveis e sensíveis para a avaliação da dor em gatos, em toda uma gama de diferentes condições clínicas, porém afirma a necessidade da realização de estudos que analisem a sua validade e aplicabilidade clínica, especialmente em relação a diferentes intensidades de dor. Na tentativa de se quantificar a dor são utilizados vários tipos de escalas subjetivas tradicionais e outras que facilitam a avaliação da efetividade da analgesia, a partir da observação de sinais comportamentais espontâneos indicativos de dor, combinada a uma resposta qualitativa à palpação da ferida cirúrgica. Faz-se necessária a utilização de escalas específicas para o tipo de dor (aguda ou crônica) e para a espécie, de modo a minimizar a subjetividade e a parcialidade dos observadores e possibilitando uma melhor assistência ao paciente.Although pain is considered the 4th vital sign and one of the most frequently observed clinical signs in domestic animals’ clinical practice, its treatment is still inadequate despite significant improvement in the last few years. Acute post-operative pain has aroused great interest due to its potential risk of developing into chronic pain, and if not treated properly, it might worsen the recovery and the patient’s quality of life. Cats are one of the least studied species of domestic animals regarding pain recognition and control. Some of the difficulties lie in pain assessment and perception. The consensus published in February 2016 about behavioral signs of pain in cats considered some signs to be reliable and sensitive for the assessment of pain in this species in many different clinical conditions, however it still states that more studies will be necessary in order to evaluate its clinical validity and applicability, especially considering the various pain intensities. As an attempt to quantify pain intensity in cats, several types of traditional subjective scales and others that facilitate pain assessment by combining the observation of spontaneous behavioral signals of pain and qualitative response to palpation of surgical wound are used as tools. It is necessary to use specific scales for each type of pain and for each specific animal species so to minimize the subjectivity and the partiality of the observers, reducing bias and improving efficacy, thus leading to a better patient care
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