334 research outputs found
Comparative Production of Bio-Oil from In Situ Catalytic Upgrading of Fast Pyrolysis of Lignocellulosic Biomass
Catalytic upgrading of fast pyrolysis bio-oil from two different types of lignocellulosic biomass was conducted using an H-ZSM-5 catalyst at different temperatures. A fixed-bed pyrolysis reactor has been used to perform in situ catalytic pyrolysis experiments at temperatures of 673, 773, and 873 K, where the catalyst (H-ZSM-5) has been mixed with wood chips or lignin, and the pyrolysis and upgrading processes have been performed simultaneously. The fractionation method has been employed to determine the chemical composition of bio-oil samples after catalytic pyrolysis experiments by gas chromatography with mass spectroscopy (GCMS). Other characterization techniques, e.g., water content, viscosity, elemental analysis, pH, and bomb calorimetry have been used, and the obtained results have been compared with the non-catalytic pyrolysis method. The highest bio-oil yield has been reported for bio-oil obtained from softwood at 873 K for both non-catalytic and catalytic bio-oil samples. The results indicate that the main effect of H-ZSM-5 has been observed on the amount of water and oxygen for all bio-oil samples at three different temperatures, where a significant reduction has been achieved compared to non-catalytic bio-oil samples. In addition, a significant viscosity reduction has been reported compared to non-catalytic bio-oil samples, and less viscous bio-oil samples have been produced by catalytic pyrolysis. Furthermore, the obtained results show that the heating values have been increased for upgraded bio-oil samples compared to non-catalytic bio-oil samples. The GCMS analysis of the catalytic bio-oil samples (H-ZSM-5) indicates that toluene and methanol have shown very similar behavior in extracting bio-oil samples in contrast to non-catalytic experiments. However, methanol performed better for extracting chemicals at a higher temperature
Comparison of Crystal Structures of 4-(benzo[\u3cem\u3eb\u3c/em\u3e]thiophen-2-yl)-5-(3,4,5-trimethoxyphenyl)-2\u3cem\u3eH\u3c/em\u3e-1,2,3-triazole and 4-(benzo[\u3cem\u3eb\u3c/em\u3e]thiophen-2-yl)-2-methyl-5-(3,4,5-trimethoxyphenyl)-2\u3cem\u3eH\u3c/em\u3e-1,2,3-triazole
The title compound, C19H17N3O3S (I), was prepared by a [3 + 2]cycloÂaddition azide condensation reaction using sodium azide and l-proline as a Lewis base catalyst. N-MethylÂation of compound (I) using CH3I gave compound (II), C20H19N3O3S. The benzoÂthioÂphene ring systems in (I) and (II) are almost planar, with r.m.s deviations from the mean plane = 0.0205 (14) in (I) and 0.016 (2) Å in (II). In (I) and (II), the triazole rings make dihedral angles of 32.68 (5) and 10.43 (8)°, respectively, with the mean planes of the benzoÂthioÂphene ring systems. The trimethÂoxy phenyl rings make dihedral angles with the benzoÂthioÂphene rings of 38.48 (4) in (I) and 60.43 (5)° in (II). In the crystal of (I), the molÂecules are linked into chains by N—H⋯O hydrogen bonds with R 2 1(5) ring motifs. After the N-methylÂation of structure (I), no hydrogen-bonding interÂactions were observed for structure (II). The crystal structure of (II) has a minor component of disorder that corresponds to a 180° flip of the benzoÂthioÂphene ring system [occupancy ratio 0.9363 (14):0.0637 (14)]
Crystal Structure of 4,5-bis-(3,4,5-trimethoxyphenyl)-2\u3cem\u3eH\u3c/em\u3e-1,2,3-triazole methanol monosolvate
The title compound, C20H23N3O6·CH3OH, was synthesized by [3 + 2] cycloÂaddition of (Z)-2,3-bisÂ(3,4,5-triÂmethÂoxyÂphenÂyl)acryloÂnitrile with sodium azide and ammonium chloride in DMF/water. The central nitroÂgen of the triazole ring is protonated. The dihedral angles between the triazole ring and the 3,4,5-triÂmethÂoxyÂphenyl ring planes are 34.31 (4) and 45.03 (5)°, while that between the 3,4,5-triÂmethÂoxyÂphenyl rings is 51.87 (5)°. In the crystal, the molÂecules, along with two methanol solvent molÂecules are linked into an R 4 4(10) centrosymmetric dimer by N—H⋯O and O—H⋯N hydrogen bonds
Synthesis and In Vitro Screening of Novel Heterocyclic Compounds as Potential Breast Cancer Agents
Longitudinal optical imaging technique to visualize progressive axonal damage after brain injury in mice reveals responses to different minocycline treatments
A high-resolution, three-dimensional, optical imaging technique for the murine brain was developed to identify the effects of different therapeutic windows for preclinical brain research. This technique tracks the same cells over several weeks. We conducted a pilot study of a promising drug to treat diffuse axonal injury (DAI) caused by traumatic brain injury, using two different therapeutic windows, as a means to demonstrate the utility of this novel longitudinal imaging technique. DAI causes immediate, sporadic axon damage followed by progressive secondary axon damage. We administered minocycline for three days commencing one hour after injury in one treatment group and beginning 72 hours after injury in another group to demonstrate the method’s ability to show how and when the therapeutic drug exerts protective and/or healing effects. Fewer varicosities developed in acutely treated mice while more varicosities resolved in mice with delayed treatment. For both treatments, the drug arrested development of new axonal damage by 30 days. In addition to evaluation of therapeutics for traumatic brain injury, this hybrid microlens imaging method should be useful to study other types of brain injury and neurodegeneration and cellular responses to treatment
Three-Dimensional Optimization of Blade Lean and Sweep for an Axial Compressor to Improve the Engine Performance
Nowadays, optimization methods have been considered as a practical tool to improve the performance of turbo-machines. For this purpose, the numerical study of the aerodynamic flow of the NASA Rotor-67 axial compressor has been investigated, and the results of this three-dimensional simulation show good agreement with experimental data. Then, the blade stacking line is changed using lean and sweep for Rotor-67 to improve the compressor performance. The third-order polynomial is selected to generate the lean and sweep changes from the hub to the shroud. The compressor flow field is solved by a Reynolds averaged Navier-Stokes solver. The genetic algorithm, coupled with the artificial neural networks, is implemented to find the optimum values for blade lean and sweep. Considering the three objective functions of pressure ratio, mass flow rate, and isentropic efficiency, the optimized rotor is obtained using the optimization algorithm. Two geometries are obtained using the optimization algorithm. The results of the optimized compressor include improving the isentropic efficiency, pressure ratio, and mass flow equal to 0.57%, 0.93%, and 1.8%, respectively. After compressor optimization, the effect of the changes in the compressor performance parameters is studied on a single spool turbojet engine. The engine is modeled by analyzing the Brayton thermodynamic cycle of the assumed turbojet engine under design point operating conditions. Results show that for the best test case, the engine with the optimized rotor, the thrust, and SFC are improved by 1.86% and 0.21%, respectively
Tacrolimus-induced nephrotoxicity and genetic variability:A review
Background: Calcineurin inhibition (CNI) is the mainstay of immunosuppressant therapy for most solid organ transplant patients. High tacrolimus levels are related with acute nephrotoxicity, but the relationship with chronic toxicity is less clear. Variation in disposition of tacrolimus is associated with genetic variation in CYP3A5. Hence, could genetic variation in CYP3A5 or other genes involved in tacrolimus disposition and effect be associated with a risk for tacrolimus-induced nephrotoxicity? To perform a review of the literature and to identify if genetic variation in CYP3A5 or other genes involved in tacrolimus disposition or effect may be associated with tacrolimus-induced nephrotoxicity and/or renal dysfunction in solid organ transplant recipients. Material/Methods: Pubmed/Medline, Embase and Google were searched from their inception till November 8th 2010 with the search terms 'tacrolimus', 'genetics', and 'nephrotoxicity' or 'renal dysfunction'. References of relevant articles were screened as well. Results: We identified 13 relevant papers. In kidney recipients, associations between donor ABCB1, recipient CCR5 genotype and tacrolimus-induced nephrotoxicity were found. CYP3A5 genotype studies in kidney recipients yielded contradictory results. In liver recipients, a possible association between recipient ACE, CYP3A5, ABCB1 and CYP2C8 genetic polymorphisms and tacrolimus-induced nephrotoxicity was suggested. In heart recipients, TGF-β genetic polymorphisms were associated with tacrolimus-induced nephrotoxicity. The quality of the studies varied considerably. Conclusions: Limited evidence suggests that variation in genes involved in pharmacokinetics (ABCB1 and CYP3A5) and pharmacodynamics (TGF-β, CYP2C8, ACE, CCR5) of tacrolimus may impact a transplant recipients' risk to develop tacrolimus-induced nephrotoxicity across different transplant organ groups.</p
ChatGPT Assisting Diagnosis of Neuro-ophthalmology Diseases Based on Case Reports
Objective: To evaluate the efficiency of large language models (LLMs) such as
ChatGPT to assist in diagnosing neuro-ophthalmic diseases based on detailed
case descriptions. Methods: We selected 22 different case reports of
neuro-ophthalmic diseases from a publicly available online database. These
cases included a wide range of chronic and acute diseases that are commonly
seen by neuro-ophthalmic sub-specialists. We inserted the text from each case
as a new prompt into both ChatGPT v3.5 and ChatGPT Plus v4.0 and asked for the
most probable diagnosis. We then presented the exact information to two
neuro-ophthalmologists and recorded their diagnoses followed by comparison to
responses from both versions of ChatGPT. Results: ChatGPT v3.5, ChatGPT Plus
v4.0, and the two neuro-ophthalmologists were correct in 13 (59%), 18 (82%), 19
(86%), and 19 (86%) out of 22 cases, respectively. The agreement between the
various diagnostic sources were as follows: ChatGPT v3.5 and ChatGPT Plus v4.0,
13 (59%); ChatGPT v3.5 and the first neuro-ophthalmologist, 12 (55%); ChatGPT
v3.5 and the second neuro-ophthalmologist, 12 (55%); ChatGPT Plus v4.0 and the
first neuro-ophthalmologist, 17 (77%); ChatGPT Plus v4.0 and the second
neuro-ophthalmologist, 16 (73%); and first and second neuro-ophthalmologists 17
(17%). Conclusions: The accuracy of ChatGPT v3.5 and ChatGPT Plus v4.0 in
diagnosing patients with neuro-ophthalmic diseases was 59% and 82%,
respectively. With further development, ChatGPT Plus v4.0 may have potential to
be used in clinical care settings to assist clinicians in providing quick,
accurate diagnoses of patients in neuro-ophthalmology. The applicability of
using LLMs like ChatGPT in clinical settings that lack access to subspeciality
trained neuro-ophthalmologists deserves further research
- …