Visible light emission from reverse-biased silicon nanometer-scale diode-antifuses

Silicon nanometer-scale diodes have been fabricated to emit light in the visible range at low power consumption. Such structures are candidates for emitter elements in Si-based optical interconnect schemes. Spectral measurements of Electroluminescence (EL) on the reverse-biased nanometer-scale diodes brought into breakdown have been carried out over the photon energy range of 1.4-2.8 eV. Previously proposed mechanisms for avalanche emission from conventional silicon p-n junctions are discussed in order to understand the origin of the emission. Also the stability of the diodes has been tested. Results indicate that our nanometer-scale diodes are basically high quality devices. Furthermore due to the nanometer-scale dimensions, very high electrical fields and current densities are possible at low power consumption. This makes these diodes an excellent candidate to be utilized as a light source in Si-based sensors and actuator application

Damage Characterization of Polypropylene Honeycomb Sandwich Panels Subjected to Low-Velocity Impact

The post-test deformation and failures of sandwich composites may involve complex interactions between various failure mechanisms. In this study, the extent of impact damages and response of the thermoplastic honeycomb sandwich are analysed through energy profile diagrams and associated load history curves. The degree of the postimpact damages of the sandwich is further characterized using an optical surfaces metrology analysis. The thickness of the honeycomb was found to influence the extent of the damage which occurred following the low-velocity impact. Thicker core was able to sustain a higher load as well as the energy absorption before total failure occurred

Altered expression of glutamate signaling, growth factor, and glia genes in the locus coeruleus of patients with major depression.

Several studies have proposed that brain glutamate signaling abnormalities and glial pathology have a role in the etiology of major depressive disorder (MDD). These conclusions were primarily drawn from post-mortem studies in which forebrain brain regions were examined. The locus coeruleus (LC) is the primary source of extensive noradrenergic innervation of the forebrain and as such exerts a powerful regulatory role over cognitive and affective functions, which are dysregulated in MDD. Furthermore, altered noradrenergic neurotransmission is associated with depressive symptoms and is thought to have a role in the pathophysiology of MDD. In the present study we used laser-capture microdissection (LCM) to selectively harvest LC tissue from post-mortem brains of MDD patients, patients with bipolar disorder (BPD) and from psychiatrically normal subjects. Using microarray technology we examined global patterns of gene expression. Differential mRNA expression of select candidate genes was then interrogated using quantitative real-time PCR (qPCR) and in situ hybridization (ISH). Our findings reveal multiple signaling pathway alterations in the LC of MDD but not BPD subjects. These include glutamate signaling genes, SLC1A2, SLC1A3 and GLUL, growth factor genes FGFR3 and TrkB, and several genes exclusively expressed in astroglia. Our data extend previous findings of altered glutamate, astroglial and growth factor functions in MDD for the first time to the brainstem. These findings indicate that such alterations: (1) are unique to MDD and distinguishable from BPD, and (2) affect multiple brain regions, suggesting a whole-brain dysregulation of such functions

DYNAMIC BEHAVIOUR OF PAPER HONEYCOMB SANDWICH PANELS

Low velocity impact tests have been conducted on paper honeycomb sandwich panels. Two panel thicknesses with span length of 100 mm are used; these are 35 mm and 41 mm, respectively. The dynamic behavior of each paper honeycomb thickness is investigated using two types of indentors: hemispherical and bar. The effect of indentor, and specimen length are studied. This includes the pattern of loaddisplacement curve collapse load and energy absorbed. It concludes that the dynamic collapse load on 41 mm thickness for hemispherical indentor increases by 5% compared with 35 mm. The impact energy absorbed for hemispherical indentor increases by 36%

Pulse-chase studies of the POMC/Beta-endorphin system in the pituitary of acutely and chronically stressed rats

Experiments were carried out to determine whether stress induces biochemical changes in the pro-opiomelanocortin (POMC) system in anterior (AL) and intermediate-posterior lobe (IPL) of rat. In a series of pulse-chase experiments, acute stress led to an increase in POMC biosynthesis and shorter half-life in AL. However, when the animals were chronically stressed, the AL no longer exhibited increased POMC synthesis. On the other hand, in the IPL, acute stress did not produce any biochemical changes, but chronic stress led to an increase in POMC synthesis and shorter half-life. These data suggest that AL and IPL are affected by acute and/or chronic exposure to stress in opposite directions and that the POMC system in AL may play an important role in stress-induced analgesia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23803/1/0000041.pd

Gastrointestinal Stromal Tumors: a Rare Neoplasm Presenting with Gastrointestinal Bleeding

Gastrointestinal stromal tumors (GIST) are rare tumors of the gastrointestinal (GI) tract that arise from primitive mesenchymal cells. GISTs occur throughout the GI tract but are usually located in the stomach and small intestine. GISTs are known with myoid, neural or mixed features of differentiation. Clinical findings are gastrointestinal bleeding, abdominal pain, and weight loss. GISTs express a heterogeneous clinical course not easily predicted. The histologic features that correlate best with development of recurrence and metastasis are mitotic activity, tumor size and the presence of tumor necrosis and most recently, mutation in the c-kit gene. Some authors specifically use the term GIST to refer to only those mesenchymal tumors that express CD117, whereas others believe that the diagnosis can be made in the absence of CD117 positivity based on clinical and morphologic features. Surgical resection remains the treatment of choice, since chemotherapy and radiation are ineffective. Long-term follow-up is imperative and recurrence rates are high. We report the case of a 60 years old female patient who presented with intermittent melena, chronic dyspepsia, and anemia. Upper digestive tract endoscopy showed a submucosal tumor, broad-based, centrally ulcerated, projection of >5 cm in the gastric corpus-antral wall as the cause of the upper gastrointestinal bleeding. Endoscopic biopsies were negative for neoplastic changes. After triple eradication therapy of Helicobacter pylori and treatment continued with proton pump inhibitor agent, the patient underwent distal gastrectomy with Billroth-I reconstruction. Histopatological studies on the surgical resection specimen revealed a GIST of smooth muscle with spindle cell, no evidence of mitotic activity but of uncertain biological behavior. One year after surgery the patient is was improved with no signs of residual Malignancy. However, metastases were found later in the liver in the next two year

Concomitant Case of Primary Biliary Cirrhosis and Autoimmune Hemolityc Anemia Responding to Corticosteroid and Ursodeoxycholic Acid in Young Woman

Primary biliary cirrhosis (PBC) is an autoimmune liver disease of unknown etiology and is characterized by chronic progressive cholestasis with destruction of the small intrahepatic bile ducts and associated most commonly with antimitochondrial antibodies. PBC is most common in women and is often associated with other autoimmune disease such as autoimmune hemolityc anemia (AIHA), rheumatoid arthritis, thyroiditis, and systemic lupus eritomatosus.            We report one case, a 20 years old woman with AIHA have been treated by corticosteroid since last year and she came to the outpatient department (OPD) with fatique and jaundice. The result of laboratory were haemoglobin 8.7 mg/dL, white blood cell 8700 mg/dL, coomb test +2, total bilirubin 33.2 mg/dL, direct bilirubin 29.3 mg/dL, γGT: 297 mg/dL and alkalyphospatase: 158 mg/dL. The result of Abdominal CT scan showed the size of liver and spleen increased and normal common bile duct (CBD). The result of ANA test, anti-nuclear (ANA) and antimitochondrial M2 (AMA M2) antibodies were positive. From the physical examination, laboratory and CT scan Abdomen; the diagnose of this patient was AIHA with PBC.            After treatment with corticosteroid (prednison 1mg/kg/day) and ursodeoxicholic acid (UDCA) for several weeks, the clinical manifestation of PBC such as jaundice getting better (the laboratory result: total bilirubin 2.7 mg/dL, direct bilirubin 1.5 mg/dL, gamma GT 80 mg/dL)

A sensitive coupled HPLC/RIA technique for separation of endorphins: Multiple forms of B-endorphin in rat pituitary intermediate vs. anterior lobe

A technique is described which couples High Performance Liquid Chromatography (HPLC) to radioimmuno assays (RIA), thus achieving high sensitivity with good specificity. This method allows the separation and detection of multiple forms of immunoreactive peptides. Using this procedure, we have characterized the B-E-like immunoreactivity in rat pituitary. It had been previously reported that most of the B-E-sized material in both intermediate and anterior lobe of rat pituitary is not true B-E1-31. We now report that N-acetyl B-E1-27, which is inactive at the opiate receptor, is indeed the predominant peptide in rat intermediate lobe, with B-E1-31 representing a low proportion of the immunoreactivity. On the other hand, the opiate active B-END1-31 is the predominant peptide in the anterior lobe. These findings have important implications for the physiological and behavioral roles of the pituitary opioids.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24297/1/0000563.pd

Pre- and Posttranslational Regulation of Β-Endorphin Biosynthesis in the CNS: Effects of Chronic Naltrexone Treatment

There appear to be two anatomically distinct Β-endorphin (ΒE) pathways in the brain, the major one originating in the arcuate nucleus of the hypothalamus and a smaller one in the area of the nucleus tractus solitarius (NTS) of the caudal medulla. Previous studies have shown that these two proopiomelanocortin (POMC) systems may be differentially regulated by chronic morphine treatment, with arcuate cells down-regulated and NTS cells unaffected. In the present experiments, we examined the effects of chronic opiate antagonist treatment on ΒE biosynthesis across different CNS regions to assess whether the arcuate POMC system would be regulated in the opposite direction to that seen after opiate agonist treatment and to determine whether different ΒE-containing areas might be differentially regulated. Male adult rats were administered naltrexone (NTX) by various routes for 8 days (subcutaneous pellets, osmotic minipumps, or repeated intraperitoneal injections). Brain and spinal cord regions were assayed for total ΒE-ir, different molecular weight immunoreactive Β-endorphin (ΒE-ir) peptides, and POMC mRNA. Chronic NTX treatment, regardless of the route of administration, reduced total ΒE-ir concentrations by 30–40% in diencephalic areas (the arcuate nucleus, the remaining hypothalamus, and the thalamus) and the midbrain, but had no effect on ΒE-ir in the NTS or any region of the spinal cord. At the same time, NTX pelleting increased POMC mRNA levels in the arcuate to ∼ 140% of control values. These data suggest that arcuate POMC neurons are up-regulated after chronic NTX treatment (whereas NTS and spinal cord systems remain unaffected) and that they appear to be under tonic inhibition by endogenous opioids. Chromatographic analyses demonstrated that, after chronic NTX pelleting, the ratio of full length ΒE 1–31 to more processed ΒE-ir peptides (i.e., ΒE 1–27 and ΒE 1–26 ) tended to increase in a dose-dependent manner in diencephalic areas. Because ΒE 1–31 is the only POMC product that possesses opioid agonist properties, and ΒE 1–27 has been posited to function as an endogenous anatgonist of ΒE 1–31 , the NTX-induced changes in the relative concentrations of ΒE 1–31 and ΒE 1–27 /ΒE 1–26 may represent a novel regulatory mechanism of POMC cells to alter the opioid signal in the synapse.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65603/1/j.1471-4159.1993.tb05820.x.pd