8,803 research outputs found

    Precision machining technology and metrology for AXAF study

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    The optical surfaces for the Advanced X-ray Astrophysical Facility (AXAF), was studied. The applicability of precision machining technology to the manufacture of the AXAF objective mirrors and the proposed and alternative methods for manufacturing and testing; (1) the AXAF technology mirrors and (2) the AXAF high resolution mirror assembly were reviewed. Surface shape and smoothness metrology for grazing incidence X-ray surfaces and the feasibility of applying heterodyne surface profilometry to nonflat surfaces were investigated. Three sets of scattering flats with known surface profiles and microtopographic character produced by precision machining and polished precision machine surfaces were analyzed

    Motilin receptor in GtoPdb v.2023.1

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    Motilin receptors (provisional nomenclature) are activated by motilin, a 22 amino-acid peptide derived from a precursor (MLN, P12872), which may also generate a motilin-associated peptide. There are significant species differences in the structure of motilin and its receptor, and in the functions of motilin. In humans and large mammals such as dog, activation of these receptors by motilin released from endocrine cells in the duodenal mucosa during fasting, induces propulsive phase III movements. This activity is associated with promoting hunger in humans. In humans and other mammals drugs and other non-peptide compounds which activate the motilin receptor may generate a more long-lasting ability to increase cholinergic activity within the upper gut, to promote upper gastrointestinal motility; this activity is suggested to be responsible for the gastrointestinal prokinetic effects of certain macrolide antibacterials (often called motilides; e.g. erythromycin, azithromycin), although for many of these molecules the evidence is sparse. Relatively high doses may induce vomiting and in humans, nausea

    Support for Integrated Ecosystem Assessments of NOAA’s National Estuarine Research Reserves System (NERRS), Volume I: The Impacts of Coastal Development on the Ecology and Human Well-being of Tidal Creek Ecosystems of the US Southeast

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    A study was conducted, in association with the Sapelo Island and North Carolina National Estuarine Research Reserves (NERRs), to evaluate the impacts of coastal development on sentinel habitats (e.g., tidal creek ecosystems), including potential impacts to human health and well-being. Uplands associated with southeastern tidal creeks and the salt marshes they drain are popular locations for building homes, resorts, and recreational facilities because of the high quality of life and mild climate associated with these environments. Tidal creeks form part of the estuarine ecosystem characterized by high biological productivity, great ecological value, complex environmental gradients, and numerous interconnected processes. This research combined a watershed-level study integrating ecological, public health and human dimension attributes with watershed-level land use data. The approach used for this research was based upon a comparative watershed and ecosystem approach that sampled tidal creek networks draining developed watersheds (e.g., suburban, urban, and industrial) as well as undeveloped sites. The primary objective of this work was to clearly define the relationships between coastal development with its concomitant land use changes and non-point source pollution loading and the ecological and human health and well-being status of tidal creek ecosystems. Nineteen tidal creek systems, located along the southeastern United States coast from southern North Carolina to southern Georgia, were sampled during summer (June-August), 2005 and 2006. Within each system, creeks were divided into two primary segments based upon tidal zoning: intertidal (i.e., shallow, narrow headwater sections) and subtidal (i.e., deeper and wider sections), and watersheds were delineated for each segment. In total, we report findings on 24 intertidal and 19 subtidal creeks. Indicators sampled throughout each creek included water quality (e.g., dissolved oxygen concentration, salinity, nutrients, chlorophyll-a levels), sediment quality (e.g., characteristics, contaminants levels including emerging contaminants), pathogen and viral indicators, and abundance and genetic responses of biological resources (e.g., macrobenthic and nektonic communities, shellfish tissue contaminants, oyster microarray responses). For many indicators, the intertidally-dominated or headwater portions of tidal creeks were found to respond differently than the subtidally-dominated or larger and deeper portions of tidal creeks. Study results indicate that the integrity and productivity of headwater tidal creeks were impaired by land use changes and associated non-point source pollution, suggesting these habitats are valuable early warning sentinels of ensuing ecological impacts and potential public health threats. For these headwater creeks, this research has assisted the validation of a previously developed conceptual model for the southeastern US region. This conceptual model identified adverse changes that generally occurred in the physical and chemical environment (e.g., water quality indicators such as indicator bacteria for sewage pollution or sediment chemical contamination) when impervious cover levels in the watershed reach 10-20%. Ecological characteristics responded and were generally impaired when impervious cover levels exceed 20-30%. Estimates of impervious cover levels defining where human uses are impaired are currently being determined, but it appears that shellfish bed closures and the flooding vulnerability of headwater regions become a concern when impervious cover values exceed 10-30%. This information can be used to forecast the impacts of changing land use patterns on tidal creek environmental quality as well as associated human health and well-being. In addition, this study applied tools and technologies that are adaptable, transferable, and repeatable among the high quality NERRS sites as comparable reference entities to other nearby developed coastal watersheds. The findings herein will be of value in addressing local, regional and national needs for understanding multiple stressor (anthropogenic and human impacts) effects upon estuarine ecosystems and response trends in ecosystem condition with changing coastal impacts (i.e., development, climate change). (PDF contaions 88 pages

    Evidence that 5-hydroxytryptamine3 receptors mediate cytotoxic drug and radiation-evoked emesis.

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    The involvement of 5-hydroxytryptamine (5-HT) 5-HT3 receptors in the mechanisms of severe emesis evoked by cytotoxic drugs or by total body irradiation have been studied in ferrets. Anti-emetic compounds tested were domperidone (a dopamine antagonist), metoclopramide (a gastric motility stimulant and dopamine antagonist at conventional doses, a 5-HT3 receptor antagonist at higher doses) and BRL 24924 (a potent gastric motility stimulant and a 5-HT3 receptor antagonist). Domperidone or metoclopramide prevented apomorphine-evoked emesis, whereas BRL 24924 did not. Similar doses of domperidone did not prevent emesis evoked by cis-platin or by total body irradiation, whereas metoclopramide or BRL 24924 greatly reduced or prevented these types of emesis. Metoclopramide and BRL 24924 also prevented emesis evoked by a combination of doxorubicin and cyclophosphamide. These results are discussed in terms of a fundamental role for 5-HT3 receptors in the mechanisms mediating severely emetogenic cancer treatment therapies

    Kajian Perubahan Mutu Kesegaran Ikan Tongkol (Euthynnus Affinis) Yang Direndam Dalam Ekstrak Rumput Laut (Eucheuma Spinosum) Dan Ekstrak Buah Bakau (Sonneratia Alba)

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    The research has been done to know the influence of seaweed extract (Eucheuma spinosum) and mangrove fruit extract (Sonneratia alba) as antibacterial in preserving tongkol fish. Seaweed (Eucheuma spinosum) and mangrove fruit (Sonneratia alba) were refined, filtered, and dissolved into sterile aquades. Fresh tongkol fish soaked in that extract added ice to maintain the temperature not more than 5 celsius degree. Observation was done to chemistry characteristic (pH), there was microbe pollution (ALT) and sensory characteristic and hedonic of tongkol fish produced by using score test. The result of observation to the sensory value and hedonic of tongkol fish which soaked in each extract give very real influence. On the other side, treatment of soak in extract did not give real influence to pH and microbe pollution (ALT).Telah dilakukan penelitian untuk mengetahui pengaruh dari ekstrak rumput laut Eucheuma spinosum dan ekstrak buah bakau Sonneratia alba sebagai antibakteri dalam mengawetkan ikan tongkol. Rumput laut Eucheuma spinosum dan buah bakau Sonneratia alba dihaluskan, disaring dan dilarutkan ke dalam aquades steril. Ikan tongkol segar direndam dalam ekstrak tersebut sambil diberi es dengan mempertahankan suhu agar tidak lebih dari 5ºC. Pengamatan dilakukan terhadap sifat kimia (pH), adanya cemaran mikroba (ALT) dan sifat sensori dan hedonik ikan tongkol yang dihasilkan dengan menggunakan uji skor. Hasil pengamatan terhadap nilai sensori dan hedonik ikan tongkol yang direndam dalam masing-masing ekstrak memberikan pengaruh yang sangat nyata. Sebaliknya perlakuan perendaman dalam ekstrak tidak memberikan pengaruh yang nyata terhadap pH dan cemaran mikroba (ALT)

    Komposisi Kimia, Senyawa Bioaktif Dan Ankga Lempeng Total Pada Rumput Laut Gracillaria Edulis

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    This study was conducted to determine the proximate composition, bioactive compound and total plate count (TPC) in Gracilaria edulis seaweed. This research used descriptive explorative method. The results showed the average value of moisture content (77.7%); protein content (39.4%); fat content (8.1%); carbohydrates by difference (71.7%); ash content (20.7%) and very low bacterial count. Phytochemical test results show this seaweed contains alkaloids, saponins, flavonoids, and triterpenoids compounds. Penelitian ini dilakukan untuk mengetahui komposisi proksimat, senyawa bioaktif dan angka lempeng total (ALT) pada rumput laut Gracilaria edulis. Penelitian ini menggunakan metode penelitian deskriptif eksploratif. Hasil penelitian menunjukkan nilai rata-rata kadar air (77,7%); protein (39,4%); kadar lemak (8,1%); karbohidrat (71,7%); kadar abu (20,7%) dan jumlah bakteri yang sangat rendah. Hasil uji fitokimia menunjukkan rumput laut ini mengandung senyawa alkaloid, saponin, flavonoid, dan triterpenoid

    A Possible Etiology of the Infertile 46XX Male Subject

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    We report on an infertile male patient with the predominant 46XX female karyotype. A testicular biopsy revealed widely separated testicular tubules, absence of sperm formation and large numbers of Leydig cells. Chromosome studies, including measurements of the X chromosomes, showed a significant difference between the lengths of the short arm of the 2 X chromosomes. This information lends support for an X-Y chromosome interchange as the etiology of this syndrome. The clinical features of this rare syndrome and other theories of etiology of XX male subjects are discussed

    Effects of neo-adjuvant chemotherapy for oesophago-gastric cancer on neuro-muscular gastric function

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    Delayed gastric emptying symptoms are often reported after chemotherapy. This study aims to characterise the effects of chemotherapy on gastric neuro-muscular function. Patients undergoing elective surgery for oesophago-gastric cancer were recruited. Acetylcholinesterase, nNOS, ghrelin receptor and motilin expressions were studied in gastric sections from patients receiving no chemotherapy (n = 3) or oesophageal (n = 2) or gastric (n = 2) chemotherapy. A scoring system quantified staining intensity (0–3; no staining to strong). Stomach sections were separately suspended in tissue baths for electrical field stimulation (EFS) and exposure to erythromycin or carbachol; three patients had no chemotherapy; four completed cisplatin-based chemotherapy within 6 weeks prior to surgery. AChE expression was markedly decreased after chemotherapy (scores 2.3 ± 0.7, 0.5 ± 0.2 and 0 ± 0 in non-chemotherapy, oesophageal- and gastric-chemotherapy groups (p < 0.03 each) respectively. Ghrelin receptor and motilin expression tended to increase (ghrelin: 0.7 ± 0.4 vs 2.0 ± 0.4 and 1.2 ± 0.2 respectively; p = 0.04 and p = 0.2; motilin: 0.7 ± 0.5 vs 2.2 ± 0.5 and 2.0 ± 0.7; p = 0.06 and p = 0.16). Maximal contraction to carbachol was 3.7 ± 0.7 g and 1.9 ± 0.8 g (longitudinal muscle) and 3.4 ± 0.4 g and 1.6 ± 0.6 (circular) in non-chemotherapy and chemotherapy tissues respectively (p < 0.05 each). There were loss of AChE and reduction in contractility to carbachol. The tendency for ghrelin receptors to increase suggests an attempt to upregulate compensating systems. Our study offers a mechanism by which chemotherapy markedly alters neuro-muscular gastric function
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