Efficient passivation of n-type and p-type silicon surface defects by hydrogen sulfide gas reaction.

An efficient surface defect passivation is observed by reacting clean Si in a dilute hydrogen sulfide-argon gas mixture (<5% H2S in Ar) for both n-type and p-type Si wafers with planar and textured surfaces. Surface recombination velocities of 1.5 and 8 cm s-1are achieved on n-type and p-type Si wafers, respectively, at an optimum reaction temperature of 550 °C that are comparable to the best surface passivation quality used in high efficiency Si solar cells. Surface chemical analysis using x-ray photoelectron spectroscopy shows that sulfur is primarily bonded in a sulfide environment, and synchrotron-based soft x-ray emission spectroscopy of the adsorbed sulfur atoms suggests the formation of S-Si bonds. The sulfur surface passivation layer is unstable in air, attributed to surface oxide formation and a simultaneous decrease of sulfide bonds. However, the passivation can be stabilized by a low-temperature (300 °C) deposited amorphous silicon nitride (a-Si:NX:H) capping layer.

Improvement in multipass Thomson scattering system comprising laser amplification system developed in GAMMA 10/PDX.

The multipass Thomson scattering (MPTS) technique is one of the most useful methods for measuring low-electron-density plasmas. The MPTS system increases Thomson scattering (TS) signal intensities by integrating all multipass (MP) signals and improving the TS time resolution by analyzing each pass signal. The fully coaxial MPTS system developed in GAMMA 10/potential-control and diverter-simulator experiments has a polarization-based configuration with image-relaying optics. The MPTS system can enhance Thomson scattered signals for improving the measurement accuracy and megahertz-order time resolution. In this study, we develop a new MPTS system comprising a laser amplification system to obtain continuous MP signals. The laser amplification system can improve degraded laser power and return an amplified laser to the MP system. We obtain continuous MP signals from the laser amplification system by improving the laser beam profile adjuster in gas scattering experiments. Moreover, we demonstrate that more MP signals and stronger amplified MP signals can be achieved via multiple laser injections to the laser amplification system in the developed MP system comprising a laser amplification system.

Effects of bilateral adrenalectomy on immunoreactive corticotropin-releasing factor in the rat median eminence and intermediate-posterior pituitary.

Immunoreactive ACTH (I-ACTH) concentrations in the anterior pituitary (AP), intermediate-posterior pituitary (IP) and plasma, and immunoreactive corticotropin-releasing factor (I-CRF) concentrations in the median eminence (ME) and IP, were determined in adrenalectomized rats from 3 h till 14 days after surgery. Plasma I-ACTH concentrations showed the typical triphasic response over time. AP I-ACTH concentrations decreased immediately after surgery, then increased to high concentrations 3 days after surgery. I-ACTH concentrations in IP did not change through these periods. I-CRF concentrations in ME and IP decreased immediately after surgery, then gradually increased to high concentrations (ME) or to control levels (IP) 14 days after surgery. These results raise the possibility that the I-CRF in IP is of hypothalamic origin.

Effect of dexamethasone on immunoreactive corticotropin-releasing factor in the rat median eminence and intermediate-posterior pituitary.

Immunoreactive ACTH (I-ACTH) concentrations in the anterior pituitary, intermediate-posterior pituitary (IP), and plasma and immunoreactive corticotropin-releasing factor (I-CRF) concentrations in the median eminence and IP were determined in rats receiving dexamethasone for various periods from 16 h to 10 days. Plasma I-ACTH concentrations were decreased 16 h after a single injection of dexamethasone. Anterior pituitary I-ACTH concentrations did not decrease until 4 days after the start of dexamethasone medication. IP I-ACTH concentrations did not change throughout these periods. I-CRF concentrations in median eminence and IP rapidly decreased after dexamethasone administration. These results raise the possibility that the source of I-CRF in the IP is hypothalamic.

Effect of various states of hydration on plasma ADH and renin in man.

To investigate the interaction between antidiuretic hormone (ADH) and renin-angiotensin system, plasma ADH and plasma renin activity (PRA) were determined in normal subjects (n = 10) under various hydrated states. Four experimental conditions, i.e., water loading, infusion of hypertonic saline, acute dehydration induced by furosemide and postural changes, were chosen. 1. Upright posture decreased plasma volume by 9.5 +/- 0.9% without significant changes in plasma osmolality. PRA increased from 5.2 +/- 0.7 to 8.3 +/- 0.8 ng/ml. However, plasma ADH did not change significantly (1.9 +/- 0.3 to 1.8 +/- 0.2 muU/ml). 2. When furosemide was administered intravenously under this condition, both plasma ADH and PRA increased to 3.1 +/- 0.5 muU/ml and 15.5 +/- 1.6 ng/ml with 11.2 +/- 1.1% decrease in plasma volume. Plasma osmolality did not change significantly. 3.Water load resulted in a decrease in plasma osmolality from 282.6 +/- 0.9 to 278.6 +/- 1.2 mOsm/kg without significant change in plasma volume. Significant decrease in plasma ADH level from 2.6 "/- 0.4 to 0.6 "/- 0.1 muU/ml was found, but PRA (7.8 +/- 1.1 ng/ml) did not change (6.3 +/- 1.0 ng/ml). 4. Hypertonic saline infusion brought about an increase in plasma osmolality to 290.1 +/- 0.8 mOsm/kg with simultaneous increase in plasma volume by 6.7 +/- 1.3%. Plasma ADH level also increased to 2.4 +/- 0.3 muU/ml, while PRA decreased to 4.2 +/- 0.3 mg/nl. Accordingly, significant correlation between changes in PRA and plasma ADH level, was not observed. We suggest that plasma osmolality is the dominant variable in regulating plasma ADH level, but in the presence of a sufficient degree of hypovolemia, the osmotic domination was overcome. On the other hand, PRA was strongly influenced by changes in effective blood volume other than changes in plasma osmolality.

Presence of immunoreactive corticotropin-releasing factor in human cerebrospinal fluid.

Immunoreactive corticotropin-releasing factor (I-CRF) was measured by radioimmunoassay and immunoaffinity chromatography in human hypothalamus and cerebrospinal fluid (CSF). Dilution curves of I-CRF in the hypothalamus and CSF were parallel to that of synthetic ovine CRF standard. I-CRF content in the hypothalamus was 643 and 281 fmol eq, respectively. I-CRF concentration in CSF was 7.4 +/- 1.1 fmol eq/ml. Sephadex G-75 column chromatography showed the main peak eluted at the position of synthetic CRF.

Effects of cyproheptadine, reserpine, and synthetic corticotropin-releasing factor on pituitary glands from patients with Cushing's disease.

Direct effects of cyproheptadine, reserpine, synthetic ovine corticotropin-releasing factor (CRF), dexamethasone, and lysine-8-vasopressin (LVP) on the secretion of immunoreactive ACTH and beta-endorphin from the adenoma and the nonadenomatous tissue of patients with Cushing's disease were examined using a superfusion system. Cyproheptadine and reserpine (10(-9)-10(-7) M of each) suppressed immunoreactive ACTH and beta-endorphin secretion from both tissues. CRF (10(10)-10(7) M) stimulated the secretion of both peptides from the nonadenomatous tissue, but only a high dose of CRF could stimulate the secretion of these peptides from some adenomas. Such CRF-induced secretion was partially suppressed by dexamethasone. LVP (10(-9)-10(-7) M) stimulated peptide secretion from both types of tissue. These results suggest direct inhibitory effects of cyproheptadine and reserpine on the secretion of these peptides from the pituitary of patients with Cushing's disease, a different stimulatory mechanism of LVP from that of CRF in these tissues, and low sensitivity of the adenoma to CRF.

Immunoreactive corticotropin-releasing factor concentrations in cerebrospinal fluid from patients with hypothalamic-pituitary-adrenal disorders.

The concentrations of immunoreactive corticotropin-releasing factor (I-CRF) in human cerebrospinal fluid (CSF) were measured utilizing immunoaffinity chromatography and RIA in patients with no endocrine disease, patients with Cushing's disease, Nelson's syndrome, Sheehan's syndrome, Addison's disease and steroid treated patients. On high performance liquid chromatography, the elution profile and retention time of I-CRF in CSF were not identical with ovine CRF. I-CRF concentrations in CSF from patients with Cushing's disease and Sheehan's syndrome were lower than those from normal subjects, however those from patients with Nelson's syndrome and Addison's disease were within the normal range. I-CRF concentrations in CSF from patients with Cushing's disease returned to normal levels 2-9 months after pituitary adenomectomy. These results suggest that CSF I-CRF concentrations are reduced by increased plasma corticosteroid levels.

Immunoreactive corticotropin and corticotropin-releasing factor in human hypothalamus, adrenal, lung cancer, and pheochromocytoma.

Immunoreactive corticotropin-releasing factor (I-CRF) and ACTH (I-ACTH) were examined using RIA, immunoaffinity chromatography, and gel filtration chromatography in human hypothalamus, adrenal (cortex and medulla), lung cancer, and pheochromocytoma. I-CRF and I-ACTH were present in these tissues. Gel filtration of I-ACTH in the adrenal, pheochromocytoma, and lung cancer showed the presence of larger amounts of I-ACTH with large molecular weight forms in contrast to the hypothalamus. Gel filtration of I-CRF in these tissues showed the main peak eluted at the position of synthetic rat CRF. High performance liquid chromatography of this main peak showed two components which eluted in the positions of synthetic rat CRF and oxidized CRF. These elution positions were the same in all tissues and identical with those in the hypothalamus. These results suggest the presence of I-ACTH and I-CRF in these tissues and that CRF outside the brain is identical to hypothalamic CRF.

Distribution and characterization of immunoreactive corticotropin-releasing factor in human tissues.

The distribution and characterization of immunoreactive corticotropin-releasing factor (I-CRF) in human tissues were examined using a rat CRF RIA, immunoaffinity chromatography, gel filtration chromatography, and high performance liquid chromatography. High concentrations of I-CRF were found in the hypothalamus and pituitary stalk. In addition, I-CRF was found in the posterior pituitary, thalamus, cerebral cortex, cerebellum, pons, medulla oblongata, spinal cord, and outside the brain and in the adrenal, lung, liver, stomach, duodenum, and pancreas. The major component of I-CRF from these tissues eluted in the position of rat CRF on gel filtration chromatography. High performance liquid chromatography of this major component showed two main peaks which eluted in the positions of CRF and oxidized CRF. These elution positions were the same in all tissues. These results indicate the presence of I-CRF outside the brain and suggest that this CRF is identical to hypothalamic CRF.

Natriuretic peptides in the human kidney.

We studied the presence of three natriuretic peptides--atrial natriuretic peptide (ANP), human brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP)--in the human kidney by radioimmunoassay and immunocytochemistry. Immunoreactive ANP, immunoreactive human BNP, and immunoreactive CNP concentrations in six kidneys were 0.12 +/- 0.07 (mean +/- SD), 0.23 +/- 0.08, and 0.37 +/- 0.07 pmol/g wet wt, respectively. Sephadex G-50 superfine column chromatography and reversed-phase high-performance liquid chromatography of kidney extracts revealed a broad peak of immunoreactive ANP comigrating with ANP-28 and urodilatin. Renal immunoreactive human BNP consisted of three components; the major component comigrated with human BNP-32. Renal immunoreactive CNP consisted of at least two components; the major component comigrated with CNP-22, and the minor component eluted in a position similar to that of authentic human CNP-53. Immunocytochemistry showed that immunoreactive human BNP was colocalized with immunoreactive ANP in the segments of distal tubules, whereas immunoreactive CNP was found predominantly in the proximal tubules. These findings indicate that these three natriuretic peptides are present in the human kidney and raise the possibility that they form a renal natriuretic peptide system that participates in the local regulation of sodium and water transport and renal circulation in the human kidney.

Detection of immunoreactive endothelin in plasma of hemodialysis patients.

Two types of radioimmunoassay (RIA) methods for measuring endothelin (ET) in human plasma were developed. One was an extraction procedure using a Sep-Pak C18 cartridge, the other being a direct method. By the extraction method, plasma ET levels were lower than the detectable limit (7 pg/ml) in normal subjects and elevated in hemodialysis patients. The absolute values obtained via the direct method were 20-times higher than those from extraction. Gel-filtration experiments revealed that this discrepancy was mainly due to immunoreactive (IR-) endothelin-like substances of high molecular mass near 11.6 kDa (large IR-ET). Extraction of the peptide by the C18 cartridge could eliminate interference by large IR-ET and is important in the accurate measurement of ET concentrations in plasma.

Increased plasma immunoreactive neuropeptide Y concentrations in phaeochromocytoma and chronic renal failure.

To investigate the clinical usefulness of radio-immunoassay of neuropeptide Y (NPY), we measured plasma immunoreactive neuropeptide Y (IR-NPY) concentrations in normal subjects (n = 21), essential hypertensive patients (n = 33), patients with phaeochromocytoma (n = 7), patients with chronic renal disease with serum creatinine levels of less than 1.9 mg/dl (n = 5) and patients with chronic renal failure whose serum creatinine levels were greater than or equal to 1.9 mg/dl (n = 18, eight without haemodialysis and 10 undergoing maintenance haemodialysis), by radio-immunoassay. Plasma IR-NPY concentrations in patients with phaeochromocytoma (577 +/- 256 pg/ml, mean +/- s.d.) were significantly higher (P less than 0.001) than those in normal subjects (151 +/- 28 pg/ml), essential hypertensive patients (177 +/- 49 pg/ml) and patients with chronic renal disease with serum creatinine levels less than 1.9 mg/dl (198 +/- 71 pg/ml). Plasma IR-NPY concentrations in patients with chronic renal failure (without haemodialysis: 330 +/- 63 pg/ml; undergoing maintenance haemodialysis: 374 +/- 80 pg/ml) were also high. These results suggest that NPY is useful as one of the tumour markers of phaeochromocytomas. However, this study revealed that patients with chronic renal failure, without phaeochromocytoma also have increased plasma IR-NPY concentrations.

Cerebellin and cerebellin mRNA in the human brain, adrenal glands and the tumour tissues of adrenal tumour, ganglioneuroblastoma and neuroblastoma.

The expression of cerebellin and cerebellin mRNA was studied by radioimmunoassay and Northern blot analysis in the human brain, adrenal gland and the tumour tissues of adrenal tumour, ganglioneuroblastoma and neuroblastoma. Immunoreactive cerebellin was detected in every region of brain studied, with the highest concentrations found in the hemisphere of the cerebellum (424.2 +/- 12.6 pmol/g wet weight, n = 6, mean +/- S.E.M.) and the vermis of the cerebellum (256.8 +/- 30.5 pmol/g wet weight). Immunoreactive cerebellin was also detected in the pituitary (8.2 +/- 1.8 pmol/g wet weight), the spinal cord (3.3 +/- 0.3 pmol/g wet weight) and the normal parts of adrenal glands (2.98 +/- 0.37 pmol/g wet weight, n = 9) and some tumour tissues, such as phaeochromocytomas, cortisol-producing adrenocortical adenomas, ganglioneuroblastomas and neuroblastomas. Northern blot analysis showed that cerebellin mRNA was highly expressed in the hemisphere and vermis of the cerebellum. Cerebellin mRNA was also expressed in other regions of the brain and the tumour tissues of phaeochromocytoma, cortisol-producing adrenocortical adenoma, ganglioneuroblastoma and neuroblastoma. Immunocytochemistry of the normal adrenal gland showed that immunoreactive cerebellin was localized in the adrenal medulla. The present study has shown the expression of cerebellin and cerebellin mRNA, not only in the cerebellum but also in other regions of the brain and some tumours, such as cortisol-producing adrenocortical adenoma, phaeochromocytoma and neuroblastoma. These findings suggest possible pathophysiological roles of cerebellin peptides, not only in the cerebellum, but also in the extra-cerebellar tissues.

Immunoreactive brain natriuretic peptide in human adrenal glands and adrenal tumors.

The presence of brain natriuretic peptide (BNP) in tissues of human adrenal glands and adrenal tumors was investigated by radioimmunoassay. Immunoreactive BNP concentrations were 0.203 +/- 0.061 pmol/g wet tissue (mean +/- SEM) in normal parts of adrenal glands (cortex and medulla, N = 8), 0.205 +/- 0.037 pmol/g wet tissue in pheochromocytomas (N = 8), 0.230 +/- 0.062 pmol/g wet tissue in aldosteronomas (N = 11) and 0.180 +/- 0.054 pmol/g wet tissue in adrenocortical adenomas with Cushing's syndrome (N = 4). Sephadex G-50 superfine column chromatography and reverse-phase high-performance liquid chromatography showed that most (> 70%) of the immunoreactive BNP in the normal part of adrenal glands was eluted in the position of human BNP-32. Sephadex G-50 superfine column chromatography of immunoreactive BNP in the pheochromocytoma and aldosteronoma showed four peaks: one in the position of gamma-BNP, one in the position of BNP-32, one between gamma-BNP and BNP-32 and one in the smaller molecular weight region. The present study has shown that immunoreactive BNP is present both in normal human adrenal glands and in adrenal tumors. Multiple molecular forms of BNP were found to be present in the tumor tissues of pheochromocytoma and aldosteronoma.

Expression of adrenomedullin and adrenomedullin mRNA in ectopic ACTH-secreting tumors.

OBJECTIVE: To study the expression of adrenomedullin, a potent vasodilator peptide originally isolated from a pheochromocytoma, in ectopic ACTH-secreting tumors. METHODS: Tumor tissue concentrations of adrenomedullin, calcitonin gene-related peptide, neuropeptide Y, endothelin-1, corticotropin-releasing hormone and ACTH were measured in three ectopic ACTH-secreting tumors by RIA. The expression of adrenomedullin mRNA was examined by northern blot analysis of tissue from one of the tumors. RESULTS: Immunoreactive adrenomedullin was detected in tumor tissues of three ectopic ACTH-secreting tumors (0.60-18.5 pmol/g wet weight). Calcitonin gene-related peptide, neuropeptide Y, endothelin-1 and corticotropin-releasing hormone were also detected in the tumor tissues. The tumor tissue concentrations of immunoreactive adrenomedullin were comparable to those of these four peptides, but much lower than those of ACTH. Northern blot analysis showed the expression of adrenomedullin mRNA in one tumor from which sufficient tissue was available for such study. The plasma concentration of immunoreactive adrenomedullin was increased in one patient (41.3 pmol/l, control 13.5 +/- 3.6 pmol/l, mean +/- S.D., n = 12). CONCLUSIONS: These results suggest that adrenomedullin is produced by ectopic ACTH-secreting tumors, together with other neuropeptides, and raise the possibility that adrenomedullin is related to the pathophysiology of these tumors.

Porcine brain natriuretic peptide-like immunoreactivity in rat tissues.

The presence of immunoreactive porcine brain natriuretic peptide in rat tissues was studied with a specific radioimmunoassay for porcine brain natriuretic peptide-26. The cross-reactivity of the antiserum used was less than 0.001% with rat atrial natriuretic peptide, rat brain natriuretic peptide-32 and rat brain natriuretic peptide-45. Immunoreactive porcine brain natriuretic peptide was detectable in various tissues of the rat, and high concentrations of immunoreactive porcine brain natriuretic peptide were found in the brain and cardiac atrium, with the highest level in the hypothalamus (159 +/- 30 fmol/gram wet tissue, mean +/- SEM, n = 4). Reverse phase high performance liquid chromatography showed that the immunoreactive porcine brain natriuretic peptide of the whole brain and heart extracts eluted mainly at an identical position to synthetic porcine brain natriuretic peptide-26. These findings indicate that porcine brain natriuretic peptide-like substance, distinct from rat brain natriuretic peptide, is present in high concentrations in the rat brain and cardiac atrium.

Increases of neuropeptide Y-like immunoreactivity in plasma during insulin-induced hypoglycemia in man.

Neuropeptide Y-like immunoreactivity (NPY-LI) in plasma during insulin-induced hypoglycemia was measured in 4 healthy male volunteers. Plasma NPY-LI increased from 167 +/- 11 pg/ml to 247 +/- 25 pg/ml 30 min after the administration of insulin (0.1 U/kg body weight IV), reached the maximum (296 +/- 6 pg/ml) 45 min after the insulin, and then decreased. These results suggest that NPY is released into the systemic circulation during insulin-induced hypoglycemia in man.

C-type natriuretic peptide in the human central nervous system: distribution and molecular form.

The distribution and molecular form of C-type natriuretic peptide (CNP) in the human central nervous system were studied with a specific radioimmunoassay for CNP-22. Immunoreactive (IR-) CNP was detectable in all regions of the brain examined (cerebral cortex, thalamus, hypothalamus, pons, and cerebellum) (0.21-0.81 pmol/g wet tissue, n = 4). The highest concentration of IR-CNP was found in the spinal cord at 1.83 +/- 0.13 pmol/g wet tissue (mean +/- SD, n = 3). Reversed-phase high performance liquid chromatography revealed a major peak migrating at the position corresponding to synthetic human CNP-53 and minor peaks comigrating with synthetic CNP-22 and the methionine-oxidized form of CNP-22, respectively. These findings suggest that IR-CNP is widely present in the human central nervous system mainly in a high molecular weight form as the major component and in the molecular form of CNP-22 as the minor component.

Human brain natriuretic peptide-like immunoreactivity in human brain.

The presence of immunoreactive human brain natriuretic peptide in the human brain was studied with a specific radioimmunoassay for human brain natriuretic peptide-32. This assay showed no significant cross-reaction with human alpha atrial natriuretic peptide, porcine brain natriuretic peptide or rat brain natriuretic peptide. Immunoreactive human brain natriuretic peptide was found in all 5 regions of human brain examined (cerebral cortex, thalamus, cerebellum, pons and hypothalamus) (0.6-6.7 pmol/g wet weight, n = 3). These values were comparable to the concentrations of immunoreactive alpha atrial natriuretic peptide in human brain (0.5-10.1 pmol/g wet weight). However, Sephadex G-50 column chromatography showed that the immunoreactive human brain natriuretic peptide in the human brain eluted earlier than synthetic human brain natriuretic peptide-32. These findings suggest that human brain natriuretic peptide is present in the human brain mainly as larger molecular weight forms.