193 research outputs found
Optimization of admixture and three-layer particleboard made from oil palm empty fruit bunch and rubberwood clones
Empty fruit bunch (EFB) is a biomass that is widely available and has the potential to be used as industrial raw material especially in wood-based industries. This study focuses on producing a particleboard by incorporating EFB with two different rubberwood clones: Prang Besar (PB) 260 and RRIM 2002, respectively. PB 260 is a commercially planted clone and wood from matured (>25 year-old) trees are used by wood-based panel manufacturers. RRIM 2002 is a new clone planted at the Malaysian Rubber Board (MRB) research trial plots and consists of only 4-year-old trees. Two types of particleboards (admixture and three-layer) with different ratios were produced. The Japanese Industrial Standard (JIS-5908 2003 particleboard) was used to evaluate mechanical and dimensional stability properties of the particleboards. From the study, it was found that admixture particleboards showed superior properties compared to three-layer particleboards. Layering EFB and rubberwood significantly decreased board performance for all properties (except internal bonding). The optimum ratios of EFB and both rubberwood clones are found to be 1:1 (50% EFB: 50% rubberwood). Meanwhile, increasing the rubberwood clones ratio to 70% lowered board performance especially for EFB (30%):RRIM 2002 clone (70%) boards which showed the lowest values for all properties for both admixture and three-layer board
Isolation and purification of membrane-bound cytochrome c from Proteus mirabilis
In the present studies, respiratory chain pathogenic bacterium, Proteus mirabilis, was investigated. In the first phase, growth profile study was performed to optimize the P. mirabilis growth. Maximum bacterial growth could be obtained between 10 – 12 h of culturing time. Down-stream processing was performed by using sonication, ultracentrifugation and detergent solubilization techniques. Partially purified respiratory contents were analyzed spectrophotometrically. Pyridine-ferrochrome and redoxspectra showed the presence of heme-c
Performance of aquatic plant species for phytoremediation of arsenic-contaminated water
This study investigates the effectiveness of aquatic macrophyte and microphyte for phytoremediation of water bodies contaminated with high arsenic concentration. Water hyacinth (Eichhornia crassipes) and two algae (Chlorodesmis sp. and Cladophora sp.) found near arsenic-enriched water bodies were used to determine their tolerance toward arsenic and their effectiveness to uptake arsenic thereby reducing organic pollution in arsenic-enriched wastewater of different concentrations. Parameters like pH, chemical oxygen demand (COD), and arsenic concentration were monitored. The pH of wastewater during the course of phytoremediation remained constant in the range of 7.3–8.4, whereas COD reduced by 50–65 % in a period of 15 days. Cladophora sp. was found to survive up to an arsenic concentration of 6 mg/L, whereas water hyacinth and Chlorodesmis sp. could survive up to arsenic concentrations of 2 and 4 mg/L, respectively. It was also found that during a retention period of 10 days under ambient temperature conditions, Cladophora sp. could bring down arsenic concentration from 6 to <0.1 mg/L, Chlorodesmis sp. was able to reduce arsenic by 40−50 %; whereas, water hyacinth could reduce arsenic by only 20 %. Cladophora sp. is thus suitable for co-treatment of sewage and arsenic-enriched brine in an algal pond having a retention time of 10 days. The identified plant species provides a simple and cost-effective method for application in rural areas affected with arsenic problem. The treated water can be used for irrigation
Effects of pretreatments of Napier Grass with deionized water, sulfuric acid and sodium hydroxide on pyrolysis oil characteristics
The depletion of fossil fuel reserves has led to
increasing interest in liquid bio-fuel from renewable biomass. Biomass is a complex organic material consisting of
different degrees of cellulose, hemicellulose, lignin,
extractives and minerals. Some of the mineral elements
tend to retard conversions, yield and selectivity during
pyrolysis processing. This study is focused on the extraction of mineral retardants from Napier grass using deionized water, dilute sodium hydroxide and sulfuric acid and subsequent pyrolysis in a fixed bed reactor. The raw biomass was characterized before and after each pretreatment
following standard procedure. Pyrolysis study was conducted
in a fixed bed reactor at 600 o�C, 30 �C/min and 30 mL/min N2 flow. Pyrolysis oil (bio-oil) collected was analyzed using standard analytic techniques. The bio-oil yield and characteristics from each pretreated sample were compared with oil from the non-pretreated sample. Bio-oil
yield from the raw sample was 32.06 wt% compared to
38.71, 33.28 and 29.27 wt% oil yield recorded from the
sample pretreated with sulfuric acid, deionized water and
sodium hydroxide respectively. GC–MS analysis of the oil
samples revealed that the oil from all the pretreated biomass had more value added chemicals and less ketones and
aldehydes. Pretreatment with neutral solvent generated
valuable leachate, showed significant impact on the ash
extraction, pyrolysis oil yield, and its composition and
therefore can be regarded as more appropriate for thermochemical conversion of Napier grass
Degradation of metalaxyl and folpet by filamentous fungi isolated from Portuguese (Alentejo) vineyard soils
Degradation of xenobiotics by microbial populations is a potential method to enhance the effectiveness of ex situ or in situ bioremediation. The purpose of this study was to evaluate the impact of repeated metalaxyl and folpet treatments on soil microbial communities and to select soil fungal strains able to degrade these fungicides. Results showed enhanced degradation of metalaxyl and folpet in vineyards soils submitted to repeated treatments with these fungicides. Indeed, the greatest degradation ability was observed in vineyard soil samples submitted to greater numbers of treatments. Respiration activities, as determined in the presence of selective antibiotics in soil suspensions amended with metalaxyl and folpet, showed that the fungal population was the microbiota community most active in the degradation process. Batch cultures performed with a progressive increase of fungicide concentrations allowed the selection of five tolerant fungal strains: Penicillium sp. 1 and Penicillium sp. 2, mycelia sterila 1 and 3, and Rhizopus stolonifer. Among these strains, mycelium sterila 3 and R. stolonifer presented only in vineyard soils treated with repeated application of these fungicides and showed tolerance >1,000 mg l−1 against commercial formulations of metalaxyl (10 %) plus folpet (40 %). Using specific methods for inducing sporulation, mycelium sterila 3 was identified as Gongronella sp. Because this fungus is rare, it was compared using csM13-polymerase chain reaction (PCR) with the two known species, Gongronella butleri and G. lacrispora. The high tolerance to metalaxyl and folpet shown by Gongronella sp. and R. stolonifer might be correlated with their degradation ability. Our results point out that selected strains have potential for the bioremediation of metalaxyl and folpet in polluted soil sites
Prognostic impact of inducible ischaemia in ischaemic left ventricular dysfunction: the REVIVED-BCIS2 trial
Challenges in the prenatal and post-natal diagnosis of mediastinal cystic hygroma: a case report
<p>Abstract</p> <p>Introduction</p> <p>Cystic hygroma is a benign congenital neoplasm that mostly presents as a soft-tissue mass in the posterior triangle of the neck. Pure mediastinal lesions are uncommon; the vast majority are asymptomatic and are an incidental finding in adulthood. The diagnosis is often made intra- or postoperatively. Prenatal identification is exceptional and post-natal diagnosis also proves challenging.</p> <p>Case presentation</p> <p>We report one such case that was mistaken for other entities in both the prenatal and immediate post-natal period. Initial and follow-up antenatal ultrasound scans demonstrated a multicystic lesion in the left chest, and the mother was counselled about the possibility of her baby having a congenital diaphragmatic hernia. Initial post-natal chest radiographs were reported as normal. An echocardiogram and thoracic computed tomography scan confirmed a complex multiloculated cystic mediastinal mass. The working diagnoses were of a mediastinal teratoma or congenital cystic adenomatous malformation. At operation, the lesion was compressed by the left lung and was found to be close to the left phrenic nerve, which was carefully identified and preserved. After excision, histopathological examination of the mass confirmed the diagnosis of cystic hygroma. Postoperative dyspnoea was observed secondary to paradoxical movement of the left hemidiaphragm and probable left phrenic neuropraxia. This settled conservatively with excellent recovery.</p> <p>Conclusion</p> <p>Despite the fact that isolated intrathoracic cystic hygroma is a rare entity, it needs to be considered in the differential diagnosis of foetal and neonatal mediastinal masses, particularly for juxtadiaphragmatic lesions. The phrenic nerve is not identifiable on prenatal ultrasound imaging, and it is therefore understandable that a mass close to the diaphragm may be mistaken for a congenital diaphragmatic hernia because of the location, morphology and potential phrenic nerve compression. Post-natal diagnosis may also be misleading as many mediastinal cystic masses have similar appearances on imaging. Therefore, as well as cystic architecture, special consideration needs to be given to the anatomical location and effect on local structures.</p
A Comprehensive Update of Anti-COVID-19 Activity of Heterocyclic Compounds
Muhammad Shahid Nazir,1 Matloob Ahmad,1 Sana Aslam,2 Ayesha Rafiq,1 Sami A Al-Hussain,3 Magdi EA Zaki3 1Department of Chemistry, Government College University, Faisalabad, Pakistan; 2Department of Chemistry, Government College Women University, Faisalabad, Pakistan; 3Department of Chemistry, Faculty of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi ArabiaCorrespondence: Matloob Ahmad; Magdi EA Zaki, Email [email protected]; [email protected]: The Coronavirus disease 2019 (COVID-19) pandemic is one of the most considerable health problems across the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the major causative agent of COVID-19. The severe symptoms of this deadly disease include shortness of breath, fever, cough, loss of smell, and a broad spectrum of other health issues such as diarrhea, pneumonia, bronchitis, septic shock, and multiple organ failure. Currently, there are no medications available for coronavirus patients, except symptom-relieving drugs. Therefore, SARS-CoV-2 requires the development of effective drugs and specific treatments. Heterocycles are important constituents of more than 85% of the physiologically active pharmaceutical drugs on the market now. Several FDA-approved drugs have been reported including molnupiravir, remdesivir, ritonavir, oseltamivir, favipiravir, chloroquine, and hydroxychloroquine for the cure of COVID-19. In this study, we discuss potent anti-SARS-CoV-2 heterocyclic compounds that have been synthesized over the past few years. These compounds included; indole, piperidine, pyrazine, pyrimidine, pyrrole, piperazine, quinazoline, oxazole, quinoline, isoxazole, thiazole, quinoxaline, pyrazole, azafluorene, imidazole, thiadiazole, triazole, coumarin, chromene, and benzodioxole. Both in vitro and in silico studies were performed to determine the potential of these heterocyclic compounds in the fight against various SARS-CoV-2 proteins. Keywords: COVID-19, SARS-CoV-2, heterocyclic nucleus, in vitro, in silico, molecular docking studie
Simultaneous 13N-Ammonia and gadolinium first-pass myocardial perfusion with quantitative hybrid PET-MR imaging: a phantom and clinical feasibility study
Background
Positron emission tomography (PET) is the non-invasive reference standard for myocardial blood flow (MBF) quantification. Hybrid PET-MR allows simultaneous PET and cardiac magnetic resonance (CMR) acquisition under identical experimental and physiological conditions. This study aimed to determine feasibility of simultaneous 13N-Ammonia PET and dynamic contrast-enhanced CMR MBF quantification in phantoms and healthy volunteers.
Methods
Images were acquired using a 3T hybrid PET-MR scanner. Phantom study: MBF was simulated at different physiological perfusion rates and a protocol for simultaneous PET-MR perfusion imaging was developed. Volunteer study: five healthy volunteers underwent adenosine stress. 13N-Ammonia and gadolinium were administered simultaneously. PET list mode data was reconstructed using ordered subset expectation maximisation. CMR MBF was quantified using Fermi function-constrained deconvolution of arterial input function and myocardial signal. PET MBF was obtained using a one-tissue compartment model and image-derived input function.
Results
Phantom study: PET and CMR MBF measurements demonstrated high repeatability with intraclass coefficients 0.98 and 0.99, respectively. There was high correlation between PET and CMR MBF (r = 0.98, p < 0.001) and good agreement (bias − 0.85 mL/g/min; 95% limits of agreement 0.29 to − 1.98). Volunteer study: Mean global stress MBF for CMR and PET were 2.58 ± 0.11 and 2.60 ± 0.47 mL/g/min respectively. On a per territory basis, there was moderate correlation (r = 0.63, p = 0.03) and agreement (bias − 0.34 mL/g/min; 95% limits of agreement 0.49 to − 1.18).
Conclusion
Simultaneous MBF quantification using hybrid PET-MR imaging is feasible with high test repeatability and good to moderate agreement between PET and CMR. Future studies in coronary artery disease patients may allow cross-validation of techniques
Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.
Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability
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