ДИАГНОСТИКА ПРИМЕСНОГО СОСТАВА ВЫСОКОЧИСТОГО МОНОСИЛАНА ПО РЕЗУЛЬТАТАМ АНАЛИЗА КОНТРОЛЬНОГО МОНОКРИСТАЛЛА КРЕМНИЯ

Elements III and V of groups of the Periodic System and carbon are the most important impurities in silicon. The estimation technique of carbon, boron and phosphorus impurity content in high−purity monosilane has been proposed. The technique involves the preparation of polycrystalline silicon by silane decomposition, growing a test single crystal by the floating zone melting method and analysis of single crystal samples by IR spectroscopy. Calculation of impurity concentration in polycrystalline silicon were performed using results on their content in the test single crystal samples, data on impurity distribution of in the liquid−solid system and sample coordinates along the ingot length. Effective impurity distribution coefficient in the «solid−liquid» system for specific growing conditions have been calculated using the Burton−Prim−Slichter equation. Results for the test silicon samples with natural isotopic composition and the enriched 28Si isotope obtained from monosilane samples with different impurity contents have been reported. Results of IR spectroscopic research of impurity composition for the test silicon single crystal are in agreement with the concentration data obtained by chromatography. The concentration of III and V group impurities in monosilane were in the range 4 ⋅ 10−9—2 ⋅ 10−6 at. %, and for carbon 2 ⋅ 10−6—6 ⋅ 10−4at.%. The measurement uncertainty by IR spectroscopy method for carbon impurity does not exceed 15 %, for boron and phosphorus — 20%. We show that the upper limit of carbon content in monosilane detected using this method is determined by its solubility in silicon, while the bottom limit depends on the detection accuracy of the IR spectroscopy technique and possible background contamination.Элементы III и V групп Периодической системы и углерод являются одними из наиболее важных примесей в кремнии. Предложена методика оценки содержания примесей углерода, бора, фосфора и мышьяка в высокочистом моносилане. Методика включает получение поликристаллического кремния по реакции гетерогенного разложения моносилана, выращивание контрольного монокристалла методом бестигельной зонной плавки, анализ монокристаллических образцов методом ИК−спектроскопии. Концентрация примесей в исходном поликристалле рассчитана с использованием результатов определения их содержания в контрольных образцах монокристаллов, данных о значении коэффициентов распределения примесей в системе «твердое тело — жидкость», координаты образца по длине слитка. Значения эффективного коэффициента распределения примесей в системе «твердое тело — жидкость» для конкретных условий выращивания оценены из уравнения Бартона— Прима—Слихтера. Приведены результаты анализа контрольных образцов кремния природного изотопного состава и обогащенного изотопом 28Si, полученных из проб моносилана с различным содержанием примесей. Установлено, что результаты ИК−спектроскопического исследования примесного состава по контрольному монокристаллу согласуются с данными о концентрации, полученными методом хроматографии. Концентрация примесей III, V групп в моносилане составила 4 ⋅ 10−9—2 ⋅ 10−6 % (ат.), углерода — 2 ⋅ 10−6— 6 ⋅ 10−4 % (ат.). Погрешность определения методом ИК−спектроскопии примеси углерода не превышала 15 %, бора и фосфора — 20 %. Показано, что верхняя граница диапазона содержания углерода в моносилане с помощью предложенной методики ограничивается его пределом растворимости в кремнии, нижняя — пределом обнаружения метода ИК−спектроскопии и возможным фоновым загрязнением.

ИЗОТОПНЫЕ ЭФФЕКТЫ В СПЕКТРАХ ИК–ПОГЛОЩЕНИЯ ЭЛЕКТРИЧЕСКИ АКТИВНЫХ ПРИМЕСЕЙ В КРЕМНИИ–28, 29 И 30 С ВЫСОКИМ ИЗОТОПНЫМ ОБОГАЩЕНИЕМ

Results are reported on an investigation of IR−absorption spectra of shallow donors and acceptors in high−purity single crystals of stable 28Si(99.99%), 29Si(99.92%) and 30Si(99,97%) silicon isotopes grown by zone melting. The content of residual boron, phosphorus and arsenic impurities Nhas been determined in the single crystals with a detection limit of 1 · 1012 at./cm3, 4 · 1011 at./cm3 and 1 · 1012 at./cm3, respectively. IR−spectroscopy results on the content of shallow donors and acceptors are in a good agreement with the data on concentration of uncompensated charge carriers obtained by Hall measurements. The parameters of absorption lines for the boron and phosphorus impurities in the single crystals of silicon isotopes have been studied. We show that a change in the isotopic composition of silicon leads to a shift in the energy spectrum of shallow impurity centers towards the high−energy range with an increase in the atomic mass of the isotope.Представлены результаты исследования спектров ИК−поглощения мелких доноров и акцепторов в высокочистых монокристаллах стабильных изотопов кремния 28Si(99,99%), 29Si(99,92%) и 30Si(99,97%), выращенных методом бестигельной зонной плавки. Определено содержание остаточных примесей бора, фосфора и мышьяка в исследуемых монокристаллах с пределом обнаружения 1 · 1012, 4 · 1011 и 1 · 1012 ат/см3 соответственно. Результаты ИК спектроскопического определения содержания мелких доноров и акцепторов хорошо согласуются с данными о концентрации свободных носителей заряда, полученными из измерений эффекта Холла. Изучены параметры линий поглощения примесей бора и фосфора в ионокристаллах изотопов кремния. Показано, что изменение изотопного состава кремния приводит к сдвигу энергетического спектра мелких примесных центров в область высоких энергий с ростом атомной массы изотопа

Increased function of pronociceptive TRPV1 at the level of the joint in a rat model of osteoarthritis pain

Objectives Blockade of transient receptor potential vanilloid 1 (TRPV1) with systemic antagonists attenuates osteoarthritis (OA) pain behaviour in rat models, but on-target-mediated hyperthermia has halted clinical trials. The present study investigated the potential for targeting TRPV1 receptors within the OA joint in order to produce analgesia. Methods The presence of TRPV1 receptors in human synovium was detected using western blotting and immunohistochemistry. In a rat model of OA, joint levels of an endogenous ligand for TRPV1, 12- ydroxyeicosatetraenoic acid (12-HETE), were quantified using liquid chromatography-tandem mass spectrometry (LCMS/MS). Effects of peripheral administration of the TRPV1 receptor antagonist JNJ-17203212 on afferent fibre activity, pain behaviour and core body temperature were investigated. Effects of a spinal administration of JNJ-17203212 on dorsal horn neuronal responses were studied. Results We demonstrate increased TRPV1 immunoreactivity in human OA synovium, confirming the diseased joint as a potential therapeutic target for TRPV1-mediated analgesia. In a model of OA pain, we report increased joint levels of 12-HETE, and the sensitisation of joint afferent neurones to mechanical stimulation of the knee. Local administration of JNJ- 17203212 reversed this sensitisation of joint afferents and inhibited pain behaviour (weight-bearing asymmetry), to a comparable extent as systemic JNJ- 17203212, in this model of OA pain, but did not alter core body temperature. There was no evidence for increased TRPV1 function in the spinal cord in this model of OA pain. Conclusions Our data provide a clinical and mechanistic rationale for the future investigation of the therapeutic benefits of intra-articular administration of TRPV1 antagonists for the treatment of OA pain

Anti-nociceptive and desensitizing effects of olvanil on capsaicin-induced thermal hyperalgesia in the rat

Background: Olvanil (NE 19550) is a non-pungent synthetic analogue of capsaicin, the natural pungent ingredient of capsicum which activates the transient receptor potential vanilloid type-1 (TRPV1) channel and was developed as a potential analgesic compound. Olvanil has potent anti-hyperalgesic effects in several experimental models of chronic pain. Here we report the inhibitory effects of olvanil on nociceptive processing using cultured dorsal root ganglion (DRG) neurons and compare the effects of capsaicin and olvanil on thermal nociceptive processing in vivo; potential contributions of the cannabinoid CB1 receptor to olvanil’s anti-hyperalgesic effects were also investigated. Methods: A hot plate analgesia meter was used to evaluate the anti-nociceptive effects of olvanil on capsaicin-induced thermal hyperalgesia and the role played by CB1 receptors in mediating these effects. Single cell calcium imaging studies of DRG neurons were employed to determine the desensitizing effects of olvanil on capsaicin-evoked calcium responses. Statistical analysis used Student’s t test or one way ANOVA followed by Dunnett’s post-hoctest as appropriate. Results: Both olvanil (100 nM) and capsaicin (100 nM) produced significant increases in intracellular calcium concentrations [Ca2+]I in cultured DRG neurons. Olvanil was able to des ensitise TRPV1 responses to further capsaicin exposure more effectively than capsaicin. Intra plantar injection of capsaicin (0.1, 0.3 and 1μg) produced a robust TRPV1-dependant thermal hyperalgesia in rats, whilst olvanil (0.1, 0.3 and 1μg) produced no hyperalgesia, emphasizing its lack of pungency. The highest dose of olvanil significantly reduced the hyperalgesic effects of capsaicin in vivo. Intraplantar injection of the selective cannabinoid CB1 receptor antagonist rimonabant (1μg) altered neither capsaicin-induced thermal hyperalgesia nor the desensitizing properties of olvanil, indicating a lack of involvement of CB1receptors. Conclusions: Olvanil is effective in reducing capsaicin-induced thermal hyperalgesia, probably via directly desensitizingTRPV1 channels in a CB 1 receptor-independent fashion. The results presented clearly support the potential for olvanil in the development of new topical analgesic preparations for treating chronic pain conditions while avoiding the unwanted side effects of capsaicin treatments

B-type natriuretic peptide-induced delayed modulation of TRPV1 and P2X3 receptors of mouse trigeminal sensory neurons

Important pain transducers of noxious stimuli are small- and medium-diameter sensory neurons that express transient receptor vanilloid-1 (TRPV1) channels and/or adenosine triphosphate (ATP)-gated P2X3 receptors whose activity is upregulated by endogenous neuropeptides in acute and chronic pain models. Little is known about the role of endogenous modulators in restraining the expression and function of TRPV1 and P2X3 receptors. In dorsal root ganglia, evidence supports the involvement of the natriuretic peptide system in the modulation of nociceptive transmission especially via the B-type natriuretic peptide (BNP) that activates the natriuretic peptide receptor-A (NPR-A) to downregulate sensory neuron excitability. Since the role of BNP in trigeminal ganglia (TG) is unclear, we investigated the expression of BNP in mouse TG in situ or in primary cultures and its effect on P2X3 and TRPV1 receptors of patch-clamped cultured neurons. Against scant expression of BNP, almost all neurons expressed NPRA at membrane level. While BNP rapidly increased cGMP production and Akt kinase phosphorylation, there was no early change in passive neuronal properties or responses to capsaicin, \u3b1,\u3b2-meATP or GABA. Nonetheless, 24 h application of BNP depressed TRPV1 mediated currents (an effect blocked by the NPR-A antagonist anantin) without changing responses to \u3b1,\u3b2-meATP or GABA. Anantin alone decreased basal cGMP production and enhanced control \u3b1,\u3b2-meATP-evoked responses, implying constitutive regulation of P2X3 receptors by ambient BNP. These data suggest a slow modulatory action by BNP on TRPV1 and P2X3 receptors outlining the role of this peptide as a negative regulator of trigeminal sensory neuron excitability to nociceptive stimuli. \ua9 2013 Vilotti et al

Nociceptors: a phylogenetic view

The ability to react to environmental change is crucial for the survival of an organism and an essential prerequisite is the capacity to detect and respond to aversive stimuli. The importance of having an inbuilt “detect and protect” system is illustrated by the fact that most animals have dedicated sensory afferents which respond to noxious stimuli called nociceptors. Should injury occur there is often sensitization, whereby increased nociceptor sensitivity and/or plasticity of nociceptor-related neural circuits acts as a protection mechanism for the afflicted body part. Studying nociception and nociceptors in different model organisms has demonstrated that there are similarities from invertebrates right through to humans. The development of technology to genetically manipulate organisms, especially mice, has led to an understanding of some of the key molecular players in nociceptor function. This review will focus on what is known about nociceptors throughout the Animalia kingdom and what similarities exist across phyla; especially at the molecular level of ion channels