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hollow fibers

Daniela Lopes, Adriana Neves Dias, Josias Merib, Eduardo Carasek
This paper describes a new configuration of the hollow fiber renewal liquid membrane (HFRLM) procedure for the high-throughput determination of the endocrine disrupting compounds 4-nonylphenol, 4-octylphenol, 4-tert-octylphenol, methylparaben, ethylparaben and bisphenol A using a 96-well plate system and high-performance liquid chromatography. In this configuration, cylindrical blades were adapted as a support for polypropylene membranes used as supported liquid membranes in the HFRLM approach. The proposed configuration exhibited important advantages including high-throughput, low solvent and sample consumption, and good analytical performance...
December 21, 2018: Analytica Chimica Acta
Shamim Haider, Jon Arvid Lie, Arne Lindbråthen, May-Britt Hägg
The simultaneous carbonization of thousands of fibers in a horizontal furnace may result in fused fibers if carbonization residuals (tars) are not removed fast enough. The optimized purge gas flow rate and a small degree angle in the furnace position may enhance the yield of high quality carbon fibers up to 97% by removing by-products. The production process for several thousand carbon fibers in a single batch is reported. The aim was developing a pilot-scale system to produce carbon membranes. Cellulose-acetate fibers were transformed into regenerated cellulose through a de-acetylation process and the fibers were carbonized in a horizontally oriented three-zone furnace...
October 15, 2018: Membranes
Defei Liu, Xin Chen, Bin Bian, Zhiping Lai, Yue Situ
Membrane bioreactors (MBRs) with polymeric/ceramic microfiltration (MF) membranes have been commonly used for wastewater treatment today. However, membrane biofouling often results in a dramatically-reduced service life of MF membranes, which limits the application of this technology. In this study, Cu hollow fiber membranes (Cu-HFMs) with low resistivity (104.8-309.8 nΩ·m) and anti-biofouling properties were successfully synthesized. Further analysis demonstrated that Cu-HFMs reduced at 625°C achieved the bimodal pore size distribution of ~1 μm and a porosity of 46%, which enable high N2 permeance (1...
2018: Frontiers in Chemistry
Yuji Aso, Mikikazu Tsubaki, Bui Hoang Dang Long, Ryo Murakami, Keisuke Nagata, Hirohisa Okano, Ngo Thi Phuong Dung, Hitomi Ohara
The present study demonstrates continuous production of d-lactic acid from cellobiose in a cell recycle fermentation with a hollow fiber membrane using recombinant Escherichia coli constructed by deleting its pyruvate formate-lyase activating enzyme gene pflA and expressing a heterologous β-glucosidase on its cell surface. The β-glucosidase gene bglC from Thermobifida fusca YX was cloned into a cell surface display vector pGV3, resulting in pGV3-bglC. Recombinant E. coli JM109 harboring the pGV3-bglC showed β-glucosidase activity (18...
October 10, 2018: Journal of Bioscience and Bioengineering
Nabil N Al-Hashimi, Rand O Shahin, Aqeel N Al-Hashimi, Ajeal M Al Ajeal, Lubna H Tahtamouni, Chanbasha Basheer
A new cetyl-alcohol-reinforced hollow fiber solid/liquid phase microextraction (CA-HF-SLPME) followed by HPLC-DAD method was developed for simultaneous determination of ezetimibe and simvastatin in human plasma and urine samples. To prepare the CA-HF-SLPME device, the cetyl-alcohol was immobilized into the pores of 2.5 cm hollow fiber micro-tube and the lumen of the micro-tube was filled with 1-octanol with the two ends sealed. Afterward, the prepared device was introduced into 10 mL of the sample solution containing the analytes with agitation...
October 13, 2018: Biomedical Chromatography: BMC
Akira Hafuka, Riho Mashiko, Ryuto Odashima, Hiroshi Yamamura, Hisashi Satoh, Yoshimasa Watanabe
This study evaluates the performance of an anaerobic membrane bioreactor (AnMBR) digesting waste activated sludge. A digestion reactor equipped with an external hollow fiber microfiltration membrane module was operated in continuous-mode for 248 days. The system demonstrated 56% volatile solids degradation at an organic loading rate of 0.40 g-VS/(L·d) in 15 days of hydraulic retention time. The average methane content in the biogas produced was 76% which is considerably high compared to that from a typical continuously stirred tank reactor...
October 2, 2018: Bioresource Technology
Ji Hyun Choi, Hojun Seo, Ju Hyang Park, Jin Ho Son, Da In Kim, Jongbok Kim, Geon Dae Moon, Dong Choon Hyun
This work introduces a new fibrous system for synergistic cancer therapy. The system consists of poly(d,l-lactic-co-glycolic acid) (PLGA) fibers with a core encapsulating an anticancer drug and a shell entrapping gold nanorods (AuNRs) as a photothermal agent. On exposure to NIR light, the photothermal agent generates heat to raise the local temperature of the fibers. If the temperature is above a glass transition (Tg ) of the polymer, the polymer chains will be mobile, increasing free volume in size within the shell...
October 2, 2018: Colloids and Surfaces. B, Biointerfaces
Sun Young Lee, Seonjeong Lee, Sung Bum Park, Ki Young Kim, Jongki Hong, Dukjin Kang
We introduce a simple online 18 O-labeling protocol for protein samples that uses a parallelizing microbore hollow fiber enzyme reactor (mHFER) as an alternative tool for online proteolytic digestion. Online 18 O-labeling is performed by separately attaching two mHFERs in parallel to a 10-port switching valve with a high-pressure syringe pump and two syringes containing 16 O- or 18 O-water. 16 O-/18 O-labeled peptides are formed in this manner and simultaneously analyzed online using nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS) without any residual trypsin activity...
October 2, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Yi Yang, Yunci Zhang, Chang Liu, Zhenni Ji, Yuxin Yin, Tingting Chu, Jing Tian, Yoichiro Ito
In our recent study, the design and performance of type-I counter-current chromatography (CCC) were changed and improved by multilayer coil. In the present study, the performance of protein separation using the multilayer coil configuration in type-I CCC was investigated under various flow rates. In order to overcome the noise signal interrupting the target peaks, a hollow fiber membrane dialyzer was inserted between CCC column outlet and inlet of the monitor. The separation was performed with a two-phase solvent system composed of polyethylene glycol 1000/dibasic potassium phosphate each at 12...
September 27, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Emily N Abada, Benjamin J Feinberg, Shuvo Roy
While extracorporeal membrane oxygenation (ECMO) is a valuable therapy for patients with lung or heart failure, clinical use of ECMO remains limited due to hemocompatibility concerns with pro-coagulatory hollow fiber membrane geometries. Previously, we demonstrated the feasibility of silicon nanopore (SNM) and micropore (SμM) membranes for transport between two liquid-phase compartments in blood-contacting devices. Herein, we investigate various pore sizes of SNM and SμM membranes - alone or with a polydimethylsiloxane (PDMS) protective coating - for parameters that determine suitability for gas exchange...
October 5, 2018: Biomedical Microdevices
Chi-Hsien Liu, Yi-Xin Liu, Wei-Chi Wu
Most bio-industrial mammalian cells are cultured in serum-free media to achieve advantages, such as batch consistency, suspended growth, and simplified purification. The successful development of a serum-free medium could contribute to a reduction in the experimental variation, enhance cell productivity, and facilitate biopharmaceuticals production using the cell culture process. Commercial serum-free media are also becoming more and more popular. However, the cell line secrets its own recombinant product and has special nutritional requirements...
October 3, 2018: Cytotechnology
Zhixian Li, Wei Huang, Yulong Cui, Zefeng Wang
We report here for the first time, to the best of our knowledge, a novel and efficient cascade Raman laser source operating at 2.8 μm by two stages of methane-filled hollow-core fibers (HCFs). In the first stage, a commercial 1064.6 nm laser is used as the pump source, and an efficient first-order Stokes wave of 1543.9 nm is obtained with a quantum conversion efficiency of ∼87% in 2 m ice-cream HCF filled with 2 bar methane gas. In the second stage, efficient 2.8 μm laser emission is also generated by the first-order stimulated Raman scattering of methane, while the pump source is the Stokes wave at 1543...
October 1, 2018: Optics Letters
Ryoichi Sakiyama, Hiroyuki Hamada, Brandon Blau, Nora Freyer, Katrin Zeilinger, Frank Schubert, Toshio Miki
OBJECTIVES: To determine the most efficient design of a hollow fiber-based bioreactor device for a bioartificial liver support system through comparative bioengineering evaluations. RESULTS: We compared two types of hollow fiber-based bioreactors, the interwoven-type bioreactor (IWBAL) and the dialyzer-type bioreactor (DBAL), by evaluating the overall mass transfer coefficient (K) and the convective coefficient (X). The creatinine and albumin mass transfer coefficients and convective coefficients were calculated using our mathematical model based on the homoporous theory and the modified Powell method...
September 27, 2018: Biotechnology Letters
Clàudia Fontàs, Enriqueta Anticó, Victòria Salvadó
A supported liquid membrane-hollow fiber system (HFSLM) has been developed to determine zinc speciation in aquatic environments. The liquid membrane consisted of an organic solution of bis-(2-ethylhexyl)phosphoric acid (D2EHPA) impregnated in the microporous of a polypropylene hollow fiber. The membrane contacted both the donor solution, that contained the metal and the stripping solution, placed in the lumen of the hollow fiber, where the metal was preconcentrated. Different parameters affecting the Zn2+ transport efficiency have been evaluated such as the composition of both the donor and stripping solutions as well as the membrane phase...
September 27, 2018: Membranes
Feifei Zhang, Wenjie Wang, Yuan Long, Hui Liu, Jijun Cheng, Lin Guo, Rongyu Li, Chao Meng, Shan Yu, Qingchuan Zhao, Shun Lu, Lili Wang, Haitao Wang, Danyi Wen
BACKGROUND: Patient-derived organoids and xenografts (PDXs) have emerged as powerful models in functional diagnostics with high predictive power for anticancer drug response. However, limitations such as engraftment failure and time-consuming for establishing and expanding PDX models followed by testing drug efficacy, and inability to subject to systemic drug administration for ex vivo organoid culture hinder realistic and fast decision-making in selecting the right therapeutics in the clinic...
September 26, 2018: Cancer communications
Stephen M Long, Hao L Tang
A membrane bioreactor (MBR) acclimatized with wastewater organic matter was employed for surface water treatment, and the feasibility of the MBR for the removal of disinfection by-product (DBP) precursors was studied. With a low pressure microfiltration hollow-fiber membrane module, a hydraulic retention time of 1.5 hours and a solids retention time of 180 days, the MBR was able to achieve 35% removal of trichloroacetic acid precursors and 21% removal of dichloroacetic acid precursors. The removal of trichloromethane (TCM) and brominated DBP precursors was unsatisfactory...
September 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Amit Sanger, Sung Bum Kang, Myeong Hoon Jeong, Min Ji Im, In Young Choi, Chan Ul Kim, Hyungmin Lee, Yeong Min Kwon, Jeong Min Baik, Ho Won Jang, Kyoung Jin Choi
Room-temperature (RT) gas sensitivity of morphology-controlled free-standing hollow aluminum-doped zinc oxide (AZO) nanofibers for NO2 gas sensors is presented. The free-standing hollow nanofibers are fabricated using a polyvinylpyrrolidone fiber template electrospun on a copper electrode frame followed by radio-frequency sputtering of an AZO thin overlayer and heat treatment at 400 °C to burn off the polymer template. The thickness of the AZO layer is controlled by the deposition time. The gas sensor based on the hollow nanofibers demonstrates fully recoverable n-type RT sensing of low concentrations of NO2 (0...
September 2018: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
G L Drusano, M N Neely, W M Yamada, Brandon Duncanson, David Brown, Michael Maynard, Michael Vicchiarelli, Arnold Louie
Treating high-density bacterial infections is a challenging clinical problem. We have a paucity of new agents that can address this problem. Pseudomonas aeruginosa is a particularly difficult pathogen to treat effectively because of the plethora of resistance mechanisms it carries.Fosfomycin is an agent discovered circa 40 years ago. Recently it has been resurrected in the United States and studied for intravenous therapy. We hypothesized that to maximize its utility, it would require combination chemotherapy when used in a clinical circumstance in high bacterial burden infections...
September 24, 2018: Antimicrobial Agents and Chemotherapy
Arnold Louie, Brandon Duncanson, Jenny Myrick, Michael Maynard, Jocelyn Nole, David Brown, Stephan Schmidt, Michael Neely, C A Scanga, Charles Peloquin, G L Drusano
A major goal for improving tuberculosis therapy is to identify drug regimens with improved efficacy and shorter treatment durations. Shorter therapies improve patient adherence to the antibiotic regimens that, in turn, decreases resistance emergence. M. tuberculosis exists in multiple metabolic states. At the initiation of therapy, the bulk of the population is in Log-Phase growth. Consequently, it is logical to focus initial therapy on these organisms. Moxifloxacin has good early bactericidal activity against Log-Phase growth bacteria and is a logical component of initial therapy...
September 24, 2018: Antimicrobial Agents and Chemotherapy
Deval Prasad Bhattarai, Arjun Prasad Tiwari, Bikendra Maharjan, Batgerel Tumurbaatar, Chan Hee Park, Cheol Sang Kim
In the present work, polypyrrole hollow fibers (PPy-HFs) were fabricated by sacrificial removal of soft templates of electrospun polycaprolactone (PCL) fibers with polypyrrole (PPy) coating through chemical polymerization of pyrrole monomer. Different physicochemical properties of as-fabricated PPy-HFs were then studied by Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infra-red (FT-IR) spectroscopy, Differential scanning calorimetry/Thermogravimetric analysis (DSC/TGA), and X-ray photoelectron spectroscopy (XPS)...
September 17, 2018: Journal of Colloid and Interface Science
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