6,097 research outputs found

    Thermochemistry of Alane Complexes for Hydrogen Storage: A Theoretical and Experimental Investigation.

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    Knowledge of the relative stabilities of alane (AlH(3)) complexes with electron donors is essential for identifying hydrogen storage materials for vehicular applications that can be regenerated by off-board methods; however, almost no thermodynamic data are available to make this assessment. To fill this gap, we employed the G4(MP2) method to determine heats of formation, entropies, and Gibbs free energies of formation for 38 alane complexes with NH(3-n)R(n) (R = Me, Et; n = 0-3), pyridine, pyrazine, triethylenediamine (TEDA), quinuclidine, OH(2-n)R(n) (R = Me, Et; n = 0-2), dioxane, and tetrahydrofuran (THF). Monomer, bis, and selected dimer complex geometries were considered. Using these data, we computed the thermodynamics of the key formation and dehydrogenation reactions that would occur during hydrogen delivery and alane regeneration, from which trends in complex stability were identified. These predictions were tested by synthesizing six amine-alane complexes involving trimethylamine, triethylamine, dimethylethylamine, TEDA, quinuclidine, and hexamine and obtaining upper limits of ΔG° for their formation from metallic aluminum. Combining these computational and experimental results, we establish a criterion for complex stability relevant to hydrogen storage that can be used to assess potential ligands prior to attempting synthesis of the alane complex. On the basis of this, we conclude that only a subset of the tertiary amine complexes considered and none of the ether complexes can be successfully formed by direct reaction with aluminum and regenerated in an alane-based hydrogen storage system

    Estimasi Posisi Vertikal Elevator pada Purwarupa AGV Logistik

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    Industri pergudangan telah mengalami transformasi signifikan melalui otomasi yang merupakan bagian dari Revolusi Industri 4.0. Transformasi ini melibatkan berbagai jenis pergudangan, termasuk yang komersial, rumah sakit, dan fasilitas PLTN. Penggunaan robot dalam proses otomasi penyimpanan telah mengubah gudang menjadi entitas otomatis sepenuhnya, meskipun membutuhkan investasi awal yang substansial. Sebagai alternatif, penggunaan robot picker memungkinkan pengambilan barang tanpa perlu perancangan awal yang rumit, mengoptimalkan infrastruktur yang sudah ada. Meskipun Indonesia masih mengimpor robot otomasi, penelusuran teknologi robot picker sedang dalam proses. Penelitian lebih mendalam diperlukan, khususnya dalam konteks sistem pengangkatan robot, terutama untuk mendukung pertumbuhan pesat industri pergudangan. Penelitian ini berfokus pada perancangan sistem vertikal elevator dan gripper untuk AGV logistik, dengan perbandingan metode estimasi ketinggian untuk mencapai akurasi terbaik dalam hasil pergerakan elevator. Dari hasil pengujian, keberhasilan pengujian hanya didapatkan 31,25% dan 39,38% yang kemungkinan dihasilkan oleh sistem girboks mengalami slip sehingga akurasi yang didapatkan sangat rendah

    Microarray foray

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    First detailed survey of waterbirds in Tirunelveli and Tuticorin districts, Tamil Nadu, India

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    The semi-arid districts of Tirunelveli and Tuticorin in the southern Indian state of Tamil Nadu consist of numerous wetlands in the form of irrigation tanks, interconnected by an ancient network of canals, and fed by the rivers originating from the Western Ghats. While these irrigation tanks have socio-economic and cultural significance, very little is known of their ecological importance. These tanks have the potential to harbor good populations of resident and wintering waterbirds but no studies have been done to confirm this. A survey was carried out in 230 irrigation tanks of various sizes in the two districts from November 2008 to January 2011. A total of 83 waterbird species were recorded. Indian Pond Heron Ardeola grayii occurred in most of the surveyed tanks. Large concentrations of wintering waterfowl such as Eurasian Wigeon Anas penelope, Northern Pintail Anas acuta, Garganey Anas querquedula were recorded in tanks closer to the coast. Based on our survey, six sites with large waterbird concentrations have been identified, one of which is Vagaikulam, an active heronry currently under threat from tree felling. These sites along with associated wetlands are important for the long term conservation of waterbirds in the region

    Pathfinder cells provide a novel therapeutic intervention for acute kidney injury

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    Pathfinder cells (PCs) are a novel class of adult-derived cells that facilitate functional repair of host tissue. We used rat PCs to demonstrate that they enable the functional mitigation of ischemia reperfusion (I/R) injury in a mouse model of renal damage. Female C57BL/6 mice were subjected to 30 min of renal ischemia and treated with intravenous (i.v.) injection of saline (control) or male rat pancreas-derived PCs in blinded experimentation. Kidney function was assessed 14 days after treatment by measuring serum creatinine (SC) levels. Kidney tissue was assessed by immunohistochemistry (IHC) for markers of cellular damage, proliferation, and senescence (TUNEL, Ki67, p16ink4a, p21). Fluorescence in situ hybridization (FISH) was performed to determine the presence of any rat (i.e., pathfinder) cells in the mouse tissue. PC-treated animals demonstrated superior renal function at day 14 post-I/R, in comparison to saline-treated controls, as measured by SC levels (0.13 mg/dL vs. 0.23 mg/dL, p<0.001). PC-treated kidney tissue expressed significantly lower levels of p16ink4a in comparison to the control group (p=0.009). FISH analysis demonstrated that the overwhelming majority of repaired kidney tissue was mouse in origin. Rat PCs were only detected at a frequency of 0.02%. These data confirm that PCs have the ability to mitigate functional damage to kidney tissue following I/R injury. Kidneys of PC-treated animals showed evidence of improved function and reduced expression of damage markers. The PCs appear to act in a paracrine fashion, stimulating the host tissue to recover functionally, rather than by differentiating into renal cells. This study demonstrates that pancreatic-derived PCs from the adult rat can enable functional repair of renal damage in mice. It validates the use of PCs to regenerate damaged tissues and also offers a novel therapeutic intervention for repair of solid organ damage in situ

    The comparing of ultrasound-guided techniques:sciatic block with continous lumbar plexus block or continous femoral nerve block for aneshtesia and analgesia of total knee replacement

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    Abstract: Background and Aims: This double blind prospective randomized clinical trial evaluated the efficacy and safety of continuous ultrasound-guided lumbar plexus block compared to continuous ultrasound-guided femoral nerve block, in the intra-operative and postoperative periods after total knee replacement. Methods: Forty ASA I-III patients were randomized to receive: continuous femoral block (n= 20, 30 ml of ropivacaine 5 mg/ml) or continuous lumbar plexus block (n= 20, 30 ml of ropivacaine 5 mg/ml) both in association with single injection sciatic nerve block. All patients received continuous infusion of 2 mg/ml of ropivacaine at 8 ml/h for 48 hours and intra- venous morphine for patient-controlled analgesia. Primary outcomes were intra-operative sufentanil consumption and verbal analogue scale (VAS) score at rest at 24h follow up. Results: Intra-operative sufentanil consumption was higher in the femoral block (FEM) group compared to the lumbar plexus block (PSOAS) group (FEM: 10.00 (10.00, 17.50) μg; PSOAS: 2.50 (0.00, 10.00) μg. p= 0.002). Obturator motor blockade occurred more frequently in the PSOAS group (70%) than in the FEM group (40%) (p=0.1); however, we found no differences in sensory blockade (p=0.6). VAS at rest was similar in the two groups at 24h postoperatively (FEM: 29.50 ± 14.74 mm; PSOAS: 25.60 ±17.42 mm. p=0.4), and throughout the follow-up period. No differences were detected in pain scores during physiotherapy. Conclusion: Continuous femoral and lumbar plexus blocks, both in association with sciatic nerve block, provided similar VAS scores at 24h, and throughout the follow-up period; intra-operative sufentanil consumption was, however, lower in the lumbar plexus block group

    Effects of the aqueous extract of fresh leaves of Calotropis procera on haematological and biochemical parameters in female rabbits

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    Calotropis procera has been reported to be medicinal and toxic in animals. A toxicological evaluation of the aqueous extract of its fresh leaves was conducted in female rabbits (Oryctolagus cuniculus). Low levels of phytochemicals (alkaloids, saponins, tannins, cardiac glycosides, and flavonoids) were found while 0.23, 0.03, 0.82 and 9.5 mg/g of iron, lead, sodium and potassium, respectively, were detected. Acute toxicity study was conducted with oral administration of 200, 400, 800 and 1600 mg/kg of the extract once to groups I, II, III and IV, respectively. Four rabbits died within 24 h and LD50 was estimated (940 mg/kg). 80, 40 and 20 mg/kg of the extract were administered daily to groups I, II, and III,respectively, during sub-acute toxicity study for 14 days. All controls were given water. Statistical analysis of aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase(ALP), albumin and protein showed no significant changes at

    Synthesising interprocedural bit-precise termination proofs

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    Proving program termination is key to guaranteeing absence of undesirable behaviour, such as hanging programs and even security vulnerabilities such as denial-of-service attacks. To make termination checks scale to large systems, interprocedural termination analysis seems essential, which is a largely unexplored area of research in termination analysis, where most effort has focussed on difficult single-procedure problems. We present a modular termination analysis for C programs using template-based interprocedural summarisation. Our analysis combines a context-sensitive, over-approximating forward analysis with the inference of under-approximating preconditions for termination. Bit-precise termination arguments are synthesised over lexicographic linear ranking function templates. Our experimental results show that our tool 2LS outperforms state-of-the-art alternatives, and demonstrate the clear advantage of interprocedural reasoning over monolithic analysis in terms of efficiency, while retaining comparable precision
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