196,175 research outputs found
Pharmacology and therapeutic role of inorganic nitrite and nitrate in vasodilatation.
Full text linkNitrite has emerged as an important bioactive molecule that can be biotransformed to nitric oxide (NO) related metabolites in normoxia and reduced to NO under hypoxic and acidic conditions to exert vasodilatory effects and confer a variety of other benefits to the cardiovascular system. Abundant research is currently underway to understand the mechanisms involved and define the role of nitrite in health and disease. In this review we discuss the impact of nitrite and dietary nitrate on vascular function and the potential therapeutic role of nitrite in acute heart failure
Hypoxic potentiation of nitrite effects in human vessels and platelets
No full textAbstract not availableRustem F. Dautov, Irene Stafford, Saifei Liu, Hugh Cullen, M. Madhani, Yuliy Y. Chirkov, John D. Horowit
KAJIAN TEKNIS GEOMETRI PELEDAKAN OVERBURDEN UNTUK MEMPERBAIKI UKURAN FRAGMENTASI BATUAN YANG SESUAI DI PIT W100 PT. MADHANI TALATAH NUSANTARA JOB SITE BATU DINDING KALIMANTAN TIMUR
Full text linkRINGKASAN
PT. Madhani Talatah Nusantara merupakan salah satu kontraktor milik
PT. Borneo Emas Hitam yaitu perusahaan Pertambangan Batubara yang berlokasi
di Desa Rampak Lambur, Kecamatan Tenggarong, Propinsi Kalimantan Timur,
yang menggunakan metode penambangan strip mine.
Dalam kegiatan penambangan Overburden di PT. Madhani Talatah
Nusantara menggunakan metode peledakan Non elektrik. Pada geometri
peledakan yang dilakukan saat ini menggunakan burden 5,5 meter, spacing 6,5
meter, kedalaman lubang bor 7,7 meter, powder factor 0,22 kg/m³, stemming 4
meter, subdrilling 0,5 meter, kolom isian 3,7 meter dan diameter lubang 152 mm.
Didapatkan hasil fragmentasi aktual di lapangan dengan boulder ≥75 cm adalah
17,4% dari produksi volume peledakan, sedangkan target perusahaan hasil
boulder tidak boleh lebih dari 15% dan batas maksimal dari powder factor sendiri
dari perusahaan adalah 0,3 kg/m³, sehingga perlu dilakukan sebuah perbaikan agar
didapatkan hasil boulder dari peledakan kurang dari 15%.
Setelah dilakukan perhitungan menurut teori R.L. Ash maka geometri
peledakan usulan adalah sebagai berikut : burden 4,6 meter, spacing 6 meter,
kedalaman lubang bor 8,12 meter, powder factor 0,29 kg/m³, stemming 4,12 m,
subdrilling 0,92 m, kolom isian 4 m dan diameter lubang 152 mm. Setelah
dilakukan perhitungan fragmentasi secara teoritis menurut teori KUZNETZOV
maka didapatkan boulder ≥75 cm adalah 12,79%. Geometri ini sesuai dengan
yang ditargetkan oleh perusahaan bahwa boulder dibawah 15% dan powder
factor masih di bawah batas maksimal dari perusahaan yaitu 0,3 kg/m³.
Kata kunci : Peledakan, Geometri, fragmentas
Platelets and mast cells promote pathogenic eosinophil recruitment during invasive fungal infection via the 5-HIAA-GPR35 ligand-receptor system
Full text linkCryptococcus neoformans is the leading cause of fungal meningitis and is characterized by pathogenic eosinophil accumulation in the context of type-2 inflammation. The chemoattractant receptor GPR35 is expressed by granulocytes and promotes their migration to the inflammatory mediator 5-hydroxyindoleacetic acid (5-HIAA), a serotonin metabolite. Given the inflammatory nature of cryptococcal infection, we examined the role of GPR35 in the circuitry underlying cell recruitment to the lung. GPR35 deficiency dampened eosinophil recruitment and fungal growth, whereas overexpression promoted eosinophil homing to airways and fungal replication. Activated platelets and mast cells were the sources of GPR35 ligand activity and pharmacological inhibition of serotonin conversion to 5-HIAA, or genetic deficiency in 5-HIAA production by platelets and mast cells resulted in more efficient clearance of Cryptococcus. Thus, the 5-HIAA-GPR35 axis is an eosinophil chemoattractant receptor system that modulates the clearance of a lethal fungal pathogen, with implications for the use of serotonin metabolism inhibitors in the treatment of fungal infections
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
The hydrodynamic and capture/retention performance of a gross pollutant trap
No full textThis research shows that gross pollutant traps (GPTs) continue to play an important role in preventing visible street waste—gross pollutants—from contaminating the environment. The demand for these GPTs calls for stringent quality control and this research provides a foundation to rigorously examine the devices. A novel and comprehensive testing approach to examine a dry sump GPT was developed. The GPT is designed with internal screens to capture gross pollutants—organic matter and anthropogenic litter. This device has not been previously investigated. Apart from the review of GPTs and gross pollutant data, the testing approach includes four additional aspects to this research, which are: field work and an historical overview of street waste/stormwater pollution, calibration of equipment, hydrodynamic studies and gross pollutant capture/retention investigations. This work is the first comprehensive investigation of its kind and provides valuable practical information for the current research and any future work pertaining to the operations of GPTs and management of street waste in the urban environment. Gross pollutant traps—including patented and registered designs developed by industry—have specific internal configurations and hydrodynamic separation characteristics which demand individual testing and performance assessments. Stormwater devices are usually evaluated by environmental protection agencies (EPAs), professional bodies and water research centres. In the USA, the American Society of Civil Engineers (ASCE) and the Environmental Water Resource Institute (EWRI) are examples of professional and research organisations actively involved in these evaluation/verification programs. These programs largely rely on field evaluations alone that are limited in scope, mainly for cost and logistical reasons. In Australia, evaluation/verification programs of new devices in the stormwater industry are not well established. The current limitations in the evaluation methodologies of GPTs have been addressed in this research by establishing a new testing approach. This approach uses a combination of physical and theoretical models to examine in detail the hydrodynamic and capture/retention characteristics of the GPT. The physical model consisted of a 50% scale model GPT rig with screen blockages varying from 0 to 100%. This rig was placed in a 20 m flume and various inlet and outflow operating conditions were modelled on observations made during the field monitoring of GPTs. Due to infrequent cleaning, the retaining screens inside the GPTs were often observed to be blocked with organic matter. Blocked screens can radically change the hydrodynamic and gross pollutant capture/retention characteristics of a GPT as shown from this research. This research involved the use of equipment, such as acoustic Doppler velocimeters (ADVs) and dye concentration (Komori) probes, which were deployed for the first time in a dry sump GPT. Hence, it was necessary to rigorously evaluate the capability and performance of these devices, particularly in the case of the custom made Komori probes, about which little was known. The evaluation revealed that the Komori probes have a frequency response of up to 100 Hz —which is dependent upon fluid velocities—and this was adequate to measure the relevant fluctuations of dye introduced into the GPT flow domain. The outcome of this evaluation resulted in establishing methodologies for the hydrodynamic measurements and gross pollutant capture/retention experiments. The hydrodynamic measurements consisted of point-based acoustic Doppler velocimeter (ADV) measurements, flow field particle image velocimetry (PIV) capture, head loss experiments and computational fluid dynamics (CFD) simulation. The gross pollutant capture/retention experiments included the use of anthropogenic litter components, tracer dye and custom modified artificial gross pollutants. Anthropogenic litter was limited to tin cans, bottle caps and plastic bags, while the artificial pollutants consisted of 40 mm spheres with a range of four buoyancies. The hydrodynamic results led to the definition of global and local flow features. The gross pollutant capture/retention results showed that when the internal retaining screens are fully blocked, the capture/retention performance of the GPT rapidly deteriorates. The overall results showed that the GPT will operate efficiently until at least 70% of the screens are blocked, particularly at high flow rates. This important finding indicates that cleaning operations could be more effectively planned when the GPT capture/retention performance deteriorates. At lower flow rates, the capture/retention performance trends were reversed. There is little difference in the poor capture/retention performance between a fully blocked GPT and a partially filled or empty GPT with 100% screen blockages. The results also revealed that the GPT is designed with an efficient high flow bypass system to avoid upstream blockages. The capture/retention performance of the GPT at medium to high inlet flow rates is close to maximum efficiency (100%). With regard to the design appraisal of the GPT, a raised inlet offers a better capture/retention performance, particularly at lower flow rates. Further design appraisals of the GPT are recommended
PENENTUAN POWDER FACTOR UNTUK MENINGKATKAN PRODUKTIFITAS ALAT MUAT DI PIT 2 WIRA PT. MADHANI TALATAH NUSANTARA JOBSITE WIRA BANJARMASIN KALIMANTAN SELATAN
No full textPenambangan batubara yang dilakukan oleh PT. Madhani Talatah Nusantara terletak di Desa Rantau Nangka, Kecamatan Sungai Pinang, Banjarmasin, Kalimantan Selatan. Kegiatan penambangannya menggunakan sistem tambang terbuka dengan metode penggalian back filling. PT. Madhani Talatah Nusantara melakukan pembongkaran lapisan tanah penutup dengan menggunakan pengeboran dan peledakan. Pola pengeboran yang diterapkan saat ini adalah selang seling (staggerd pattern) menggunakan satu unit alat bor Drilltech Mission D245S dengan diameter mata bor 7,87 inch, dan arah pengeboran tegak. Metode peledakan yang digunakan adalah nonel (non electric). Untuk geometri peledakan yang digunakan saat ini burden 6,5 m, spacing 7,5 m, stemming 4,5 m, powder column 4 m, kedalaman lubang ledak rata-rata 8,5 m, dan powder factor 0,24 kg/m³, Stiffness ratio sebesar 1,23. Nilai powder factor yang digunakan saat ini masih belum optimal. Diperoleh fragmentasi hasil peledakan yang kurang seragam dan boulder dengan ukuran ≥ 2,5 m sebesar 22,69 % menurut perhitungan menggunakan teori KUZNETZOV, sehingga menyebabkan waktu edar alat muat menjadi besar dan secara langsung mempengaruhi besarnya produktifitas. Untuk produktifitas alat muat Backhoe Komatsu PC 2000 menggunakan geometri peledakan saat ini diperoleh sebesar 644 bcm/jam dan belum mencapai target yang ditentukan oleh perusahaan yaitu 790 bcm/jam. Untuk mengoptimalkan nilai powder factor dan sekaligus meningkatkan produktifitas alat muat Backhoe Komatsu PC 2000 maka dilakukan perubahan geometri peledakan dengan burden 6 m, spacing 7 m, stemming 4,5 m, powder column 4,5 m, kedalaman lubang ledak rata-rata 9 m, dan powder factor 0,29 kg/m³, stiffness ratio meningkat dari 1,23 menjadi 1,33 Menurut R.L. Ash penggunaan stiffness ratio 1,33 pada geometri usulan maka hasil peledakannya lebih menguntungkan daripada geometri saat ini dilapangan. Berdasarkan geometri peledakan usulan terdapat kenaikan nilai powder factor, kenaikan nilai powder factor ini dikarenakan pada penggunaan powder factor saat ini dilapangan fragmen yang dihasilkan masih terdapat banyak boulder sehingga secara tidak langsung menyebabkan prodiktifitas alat muatnya belum mencapai target. Dengan menggunakan geometri usulan ini diperoleh fragmen hasil peledakan yang lebih seragam dan terdapat penurunan jumlah boulder yaitu ≥ 100 cm sebesar 10 % menurut perhitungan teori KUZNETZOV, sehingga terjadi penurunan waktu edar alat muat Backhoe Komatsu PC 2000 dari 0,59 menit menjadi 0,54 menit. Penurunan waktu edar ini akan mengakibatkan meningkatnya produktifitas alat muat Backhoe Komatsu PC 2000 dari 644 bcm/jam menjadi 695 bcm/jam
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