31 research outputs found
Kenaf Bast Fibers—Part I: Hermetical Alkali Digestion
The objective of this study was to develop a hermetical alkali digestion process to obtain single cellulosic fibers from kenaf bast. Kenaf bast were hermetically digested into single fiber using a 5% sodium hydroxide solution for one hour at four different temperatures (80°C, 110°C, 130°C, and 160°C). The hermetical digestion process used in this study produced fibers with high cellulose content (84.2–92.3%) due to the removal of lignin and hemicelluloses. The surface hardness and elastic modulus of the fibers digested at 130°C
and 160°C were improved significantly compared with those digested at 80°C. The tensile modulus and tensile strength of the individual fibers reduced as the digestion temperature increased from
110°C to 160°C. Micropores were generated in fiber cell wall when the fibers were digested at 130°C
and 160°C. The studies on the composites that were made from polypropylene reinforced with the digested fibers indicated that the compatibility between the digested fibers and polypropylene matrix was poor
Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey
Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020
Oxygen-peroxide (Eop) Delignification and Peroxide (P) Bleaching of Bagasse Kraft Pulp
699-706An EopQP sequence
is used to delignify and bleach a bagasse kraft pulp. In the Eop step, a reduction
of the kappa number by 60 per cent and improvement in the brightness by 16.5 units
were achieved. The Q step reduces the content of Mn, Fe and Cu ions by 48-60
per cent. A bleaching system consisting of 4 per cent H2O2,
2.5 per cent NaOH, 0.3 per cent MgSO4, and 0.05 per cent DTPMPA could
bleach the EopQ treated pulp to 80 per cent ISO brightness, 2.6 kappa number and
~700 mL/g viscosity. The brightness is increased to 82 per cent at reasonable viscosity
values (> 650 mL/g) by adding 0.05 per cent 1, 10-phenanthroline to a
bleaching system containing lower peroxide concentration (3 per cent) and higher
DTPMPA charge (0.1 per cent)
Sustainable and economical dolomite-modified biochar for efficient removal of anionic dyes
Dyes induce acute to chronic illnesses in humans and aquatic animals. This study tested dolomite-modified rice husk biochar (DRHB) to eliminate anionic reactive dyes Remazol Brilliant Blue (RBB) and Reactive Black 5 (RB-5) from simulated wastewater solutions. DRHB was produced by pretreating rice husk biomass with the natural mineral dolomite (CaMg(CO3)2) solution following pyrolysis step at 700 °C for 4 h at 8 °C min−1. Pristine rice husk biochar (PRHB) was made by pyrolyzing rice husk for 4 h at 700 °C. The DRHB and PRHB were characterized via different techniques including, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Scanning electron microscopy (SEM). Afterwards, DRHB was used to get rid of the dyes in the wastewater solutions, and the effects of dose, pH, and contact duration were studied. Both RBB and RB-5 exhibited maximal adsorption capacities of 52.07 and 35.518 mg/g at 50 °C, respectively, and the findings matched well with the Langmuir model, demonstrating monolayer adsorption. For this system, the pseudo-second-order fit is optimal, pointing to chemisorption of both substances. The outcomes presented higher adsorption for RBB (95.63%) compared to RB-5 (85.20%) at 70 mg/L concentration, pH 6, 4 hr. contact time, and 0.3 mg of DRHB dosage. The primary mechanism to remove of both dyes was chemisorption via π-π bond and hydrogen bond. These findings provide insights to build an economical, and sustainable anionic dyes removal technique especially for the third world nations
Pulping of <i>Casuarina glauca </i>with ASAM - An Environmental Friendly Process
799-806ASAM pulping
process has been experimented on Casuarina glauca. The pulping
parameters such as methanol concentration, cooking time, chemical charge, and alkali
ratio, affecting the chemical and physical properties of the pulp are determined
.. For ASAM I cooks, NaOH is the supporting alkali, while in ASAM II pulping, Na2CO3
is the supporting alkali. The best ASAM I pulping is achieved at 22.5 and 25 per
cent chemical charge with 0.7 and 0.8 alkali ratio while the best ASAM II
pulping is achieved at 27.5 per cent chemical charge and 0.6 alkali ratio. When
both the pure alkalies were used, some changes in the pulp properties were
observed by varying the ratio of NaOH: Na2CO3. Pulp- and papermaking
properties of Casuarina cooked by the ASAM process are observed to be superior
to Casuarina pulp obtained by the kraft process
Cellulose Nanofibril Stabilized Pickering Emulsion Templated Aerogel with High Oil Absorption Capacity
Amino-Functionalized Cellulose Nanofiber/Lignosulfonate New Aerogel Adsorbent for the Removal of Dyes and Heavy Metals from Wastewater
Due to the increasingly widespread water pollutants and the high cost of treatment methods, there is a demand for new, inexpensive, renewable, and biodegradable adsorbent materials for the purification of wastewater contaminants. In this study, a new biocomposite aerogel (Amf-CNF/LS) was prepared using a chemically cross-linking method between the amino-functionalized cellulose nanofibers (Amf-CNF) and lignosulfonates (LS). The physical and chemical properties of the prepared aerogel were investigated using several techniques including elemental analysis, scanning electron microscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and N2 adsorption-desorption analysis. The Amf-CNF/LS aerogel was then applied for the removal of methylene blue (MB), rhodamine B dye (RhB), and the heavy metal cadmium ion (Cd2+) from synthetic wastewater solutions. The adsorption parameters controlling the adsorption process including the pH, contact time, adsorbent dosage, and adsorbate concen-tration were optimized. High adsorption kinetics and isotherms were observed, with the adsorption isotherms of the Amf-CNF/LS aerogel fitting the Langmuir model with maximum adsorption capacities of 170.94, 147.28, and 129.87 mg/g for MB, RhB, and Cd2+, respectively. These results show that Amf-CNF/LS aerogel is a promising green and inexpensive adsorbent for MB, RhB, and Cd2+ removal from wastewater
Comparative study between double plating and Y plate in management of intercondylar humeral fracture
Background: Intercondylar humeral fracture is one of the commonest & challenging fractures of young adult and counts for about 30% of all elbow fractures. Aim: Evaluation of two groups of patients, group 1 and group 2 managed by double plates and group B by Y plate Materials and Methods: This Prospective study was conducted on 44 patients, Group 1 22 patient and Group 2 22 patient. The study included patients aged between 16-59 years with intercondylar humeral fracture type C according to AO classification while patients with compound fractures, osteoporotic bone, pathological fractures, and patients aging less than 16 years and more than 59 years were excluded. Follow up at 3 and 6 months. Results: Range of movement after 3 & 6 months was 84±31 and 98±35 respectively in group 1 which was relatively high compared to 48±25 and 71±21 respectively in group 2. MAYO Elbow Performance Score after 3 & 6 months was 71±21 and 82±23 respectively in group 1 which was relatively high compared to 48±14 and 73±12 respectively in group 2. 
Assessment of telescoping nail in the management of long bones fractures and deformities in patients with osteogenesis imperfecta
Background: Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and multiple fractures. Approximately 90% are caused by mutation in COL1A1 or COL1A2 genes, the disease is transmitted either autosomal dominantly or recessively or appears as a spontaneous mutation. Protein product of these two genes is type I collagen, the major structural protein in the bone and skin, which is affected in quality, quantity or both. The most distinct feature of this disease is repeated fractures and deformities which are very challenging to treat. Making the bone harder by bisphosphonate treatment and by Intramedullary splinting of long bones is the standard of care in most pediatric orthopedic centers. The problem of treating young child with a fixed length intramedullary rod, is overgrowth of the bone beyond the edge of the nail, creating a segment of bone which is unsupported and very liable to fractures and deformities. The need for a device that elongates with bone growth (telescoping intramedullary nail) was necessary to overcome this problem. There were different types of telescoping Intramedullary nails (baily-dubow, Sheffield, interlocking telescoping nail that has been used for the treatment of Osteogenesis imperfecta
Cellulose Nanofibril Stabilized Pickering Emulsion Templated Aerogel with High Oil Absorption Capacity
Nanocellulose-based aerogels, featuring a three-dimensional
porous
structure, are considered as a desirable green absorbent because of
their exceptional absorption performance as well as the abundance
and renewability of the raw material. However, these aerogels often
require hydrophobic modification or carbonization, which is often
environmentally harmful and energy-intensive. In this study, we introduce
a Pickering-emulsion-templating approach to fabricate a cellulose
nanofibril (CNF) aerogel with a hierarchical pore structure, allowing
for high oil absorption capacity. n-Hexane–CNF
oil-in-water Pickering emulsions are prepared as an emulsion template,
which is further lyophilized to create a hollow microcapsule-based
CNF (HM-CNF) aerogel with a density ranging from 1.3 to 6.1 mg/cm3 and a porosity of ≥99.6%. Scanning electron microscopy
and Brunauer–Emmett–Teller analyses reveal the HM-CNF
aerogel’s hierarchical pore structure, originating from the
CNF Pickering emulsion template, and also confirm the aerogel’s
very high surface area of 216.6 m2/g with an average pore
diameter of 8.6 nm. Furthermore, the aerogel exhibits a maximum absorption
capacity of 354 g/g and 166 g/g for chloroform and n-hexadecane, respectively, without requiring any surface modification
or chemical treatment. These combined findings highlight the potential
of the Pickering-emulsion-templated CNF aerogel as an environmentally
sustainable and high-performance oil absorbent