bluuebunny/crossref_metadata_2025 huggingface dataset:
Canine urethral sphincter pressure profile under incremental inflation of an artificial cuff: a cadaver study
Authors: Milodowski E. J. , Friend E. J. , Granger N. , Doran I. C. P.
Published: November 2018

Objectives

To determine whether artificial urethral sphincter filling volume is proportional to peak pressure exerted on the urethra.

Materials and Methods

Urethral pressure profilometry was performed in five female, medium‐sized, mixed‐breed canine cadavers following artificial urethral sphincter placement. Maximum urethral pressure was recorded following sequential incremental inflation of 0.15 mL and compared to baseline pressure and between dogs using two‐way analysis of variance.

Results

Artificial urethral sphincter placement in cadavers was associated with an increase in urethral pressure, which was significantly correlated with inflation volume. The correlation was non‐linear and demonstrated considerable individual variation. Maximum urethral pressures after artificial urethral sphincter placement exceeded those reported in conscious continent dogs within a narrow volume range, in which a 0.15 mL infusion more than doubled maximal urethral pressures.

Clinical Significance

Rapid increases in urethral pressure from the artificial urethral sphincter over a small range of filling volumes (0.15 mL increments) might explain why some clinical cases can become suddenly dysuric following incremental inflations. We suggest that smaller increments of filling (0.05 to 0.1 mL) may achieve finer pressure control.
Capillary flow disturbances after experimental subarachnoid hemorrhage: A contributor to delayed cerebral ischemia?
Authors: Anzabi Maryam , Angleys Hugo , Aamand Rasmus , Ardalan Maryam , Mouridsen Kim , Rasmussen Peter Mondrup , Sørensen Jens Christian Hedemann , Plesnila Nikolaus , Østergaard Leif , Iversen Nina Kerting
Published: November 2018

Background

The high mortality and morbidity after SAH is partly due to DCI, which is traditionally ascribed to development of angiographic vasospasms. This relation has been challenged, and capillary flow disturbances are proposed as another mechanism contributing to brain damage after SAH.

Objective

To investigate capillary flow changes 4 days following experimental SAH.

Methods

SAH was induced by endovascular perforation of circle of Willis. We used TPM to evaluate blood flow characteristics. Cortical capillary diameters were investigated by both TPM and histology.

Results

We found elevated CTH and MTT of blood in SAH mice compared to sham animals. We observed capillaries with stagnant RBCs, and capillaries with increased RBC LD in the SAH group, suggesting severe blood maldistribution among cortical capillaries. Favoring that these capillary flow changes were primary to upstream vasoconstrictions, TPM showed no significant differences in arteriolar diameter between groups, while histological examination showed reduced capillary diameter in SAH group.

Conclusion

Our study shows profound subacute hypoperfusion and capillary flow disturbances in a mouse SAH model and suggests that these changes are the result of changes in capillary function, rather than upstream vasospasm.
YocM a small heat shock protein can protect Bacillus subtilis cells during salt stress
Authors: Hantke Ingo , Schäfer Heinrich , Janczikowski Armgard , Turgay Kürşad
Published: November 2018

Small heat shock proteins (sHsp) occur in all domains of life. By interacting with misfolded or aggregated proteins these chaperones fulfill a protective role in cellular protein homeostasis. Here, we demonstrate that the sHsp YocM of the Gram‐positive model organism Bacillus subtilis is part of the cellular protein quality control system with a specific role in salt stress response. In the absence of YocM the survival of salt shocked cells is impaired, and increased levels of YocM protect B. subtilis exposed to heat or salt. We observed a salt and heat stress‐induced localization of YocM to intracellular protein aggregates. Interestingly, purified YocM appears to accelerate protein aggregation of different model substrates in vitro. In addition, the combined presence of YocM and chemical chaperones, which accumulate in salt stressed cells, can facilitate in vitro a synergistic protective effect on protein misfolding. Therefore, the beneficial role of YocM during salt stress could be related to a mutual functional relationship with chemical chaperones and adds a new possible functional aspect to sHsp chaperone activities.
Updates on Lycianthes (Solanaceae): a new species from Brazil, notes on taxonomy, and a key to identification of Brazilian species
Authors: Costa‐Silva Rafael , de Fátima Agra Maria
Published: November 2018

During studies of the genus Lycianthes as part of a taxonomic treatment for the Brazilian flora, a new species, Lycianthes bitteri Costa‐Silva & Agra, was recognized from Bahia State, which is described and illustrated here. It is member of Lycianthes subg. Polymeris and related to L. pauciflora (Vahl) Bitter and L. cearaensis Bitter, from which it differs by having petioles depressed adaxially, calyx with linear appendices in two series, radiate and widely spreading, ovary somewhat conical, and indument composed of a mix of dendritic and stellate trichomes. Information about its distribution, conservation status, and affinities with other Lycianthes species are discussed. Additionally, four new synonyms and a lectotypification are proposed, and a key to all Brazilian Lycianthes species is presented.
Cucumis omissus sp. nov. (Cucurbitaceae) from southern Arabia and Ethiopia and its phylogenetic position
Authors: Thulin Mats , Heidari Nahid , Larsson Anders
Published: November 2018

The new species Cucumis omissus Thulin from Yemen, Oman and Ethiopia is described and illustrated. According to phylogenetic analyses based mainly on nuclear ribosomal ITS sequences and chloroplast trnG sequences, the new species is sister to C. hastatus from Somalia and Ethiopia. A map showing the distributions of both C. omissus and C. hastatus is provided and morphological differences between these two species are highlighted. Cucumis omissus has been confused with C. pustulatus and C. prophetarum in the literature and in herbaria, and morphological differences from these two species are provided as well. Oreosyce africana is nested within Cucumis in this, as well as in several previous studies. We clarify that when O. africana is treated as a Cucumis, its correct name is C. subsericeus.
Impaired electron transfer accounts for the photosynthesis inhibition in wheat seedlings (Triticum aestivum L.) subjected to ammonium stress
Authors: Wang Feng , Gao Jingwen , Shi Songmei , He Xinhua , Dai Tingbo
Published: November 2018

No single mechanism can provide an adequate explanation for the inhibition of photosynthesis when plants are supplied with ammonium (NH4+) as the sole nitrogen (N) source. We performed a hydroponic experiment using two N sources [5 mM NH4+ and 5 mM nitrate (NO3−)] to investigate the effects of NH4+ stress on the photosynthetic capacities of two wheat cultivars (NH4+‐sensitive AK58 and NH4+‐tolerant XM25). NH4+ significantly inhibited the growth and light‐saturated photosynthesis (Asat) of both cultivars, but the extent of such inhibition was greater in the NH4+‐sensitive AK58. The CO2 concentration did not limit CO2 assimilation under NH4+ nutrition; though both stomatal and mesophyll conductance were significantly suppressed. Carboxylation efficiency (CE), light‐saturated potential rate of electron transport (Jmax), the quantum efficiency of PSII (ΦPSII), electron transport rate through PSII [Je(PSII)], and Fv/Fm were significantly reduced by NH4+. As a result, NH4+ nutrition resulted in a significant increase in the production of hydrogen peroxide (H2O2) and superoxide anion radicals (O2•−), but these symptoms were less severe in the NH4+‐tolerant XM25, which had a higher capacity of removing elevated reactive oxygen species (ROS). Thus, NH4+ N sources might decreased electron transport efficiency and increased the production of ROS, exacerbating damage to the electron transport chain, leading to a reduced plant photosynthetic capacity.
Multidisciplinary rehabilitation of eosinophilic granuloma with bone graft surgery and a modified implant‐supported hybrid prosthesis: A case report with a 6‐year follow‐up
Authors: Kurt Meral , Bal Bilge Turhan , Uraz Ahu , Kahraman Sevil
Published: November 2018

Eosinophilic granuloma is the most common form of Langerhans cell histiocytosis and corresponds with bone lesions characterized by pain, rapid growth, and high tendency of recurrence after inadequate curettage. It is a rare disease that is difficult to diagnose clinically and radiographically because it mimics other odontogenic cysts and tumors. In this report, the reconstruction of an osseous defect with an iliac graft and a modified implant‐supported hybrid prosthesis after surgical excision of an eosinophilic granuloma in the mandible of a 27‐year‐old male patient was described. The patient was satisfied with the functional and esthetic results of the implant‐supported restoration and a 6‐year follow‐up showed no sign of recurrence.
Effect of Casting Conditions on SMM Blended Polyethersulfone Hydro–Phobic/–Philic Composite Membranes: Characteristics and Desalination Performance in Membrane Distillation
Authors: Qtaishat M. , Khayet M. , Matsuura T. , Khulbe K.C.
Published: November 2018

This study aims at further improvement and development of the novel hydro–phobic/–philic composite membranes which are made specifically for membrane distillation (MD). This was attempted by studying the effect of the casting conditions during the membrane preparation process by the phase inversion method. Two variables were chosen to study, which are the evaporation time before gelation and the gelation path temperature. Some of the membranes were allowed to evaporate at room temperature for 2 or 3 minutes to study the effect of evaporation time. The temperature of the gelation path was varied to 4°C, 20°C or 60°C in order to study the gelation path temperature effect. The prepared membranes were characterized using gas permeation test, measurement of the liquid entry pressure of water (LEPw), X–ray photoelectron spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM). The effects of the casting conditions on the membrane morphology were identified, which enabled us to link the membrane morphology to the membrane performance. The membranes were then tested for desalination of 0.5 M NaCl solution by direct contact membrane distillation (DCMD) and the results were compared to commercial polytetraflouroethylene (PTFE) membrane. It was found that the membrane which was prepared with no evaporation time produced better flux than those with evaporation time. Regarding the gelation path temperature; the membrane prepared with gelation path temperature of 4°C was better than those prepared with gelation path temperature of 20 or 60°C. It should be emphasized that the DCMD flux of the membranes prepared with no evaporation time or with a gelation path temperature of 4°C was superior to the commercial one. Furthermore, all the prepared membranes were tested successfully for the desalination application. In other words, no NaCl was detected in the permeate.
Development of Novel Membranes Based on Electro–spun Nanofibers and Their Application in Liquid Filtration, Membrane Distillation and Membrane Adsorption
Authors: Matsuura T. , Feng C. , Khulbe K. C. , Rana D. , Singh G. , Gopal R. , Kaur S. , Ramakrishna S. , Tabe S.
Published: November 2018

Electro–spinning is known as a simple and versatile method to produce nonwoven membranes made out of nanofibers. A wide range of polymers and blends can be used to yield nanofibers. Commonly used membrane polymers such as cellulose acetate (CA), polysulfone (PSU) and polyvinylidene fluoride (PVDF) have been successfully electro–spun to form nonwoven nanofiber membranes for water filtration. Investigations have revealed that electro–spun nanofibrous membranes (ENMs) possess high–flux rates and low transmembrane pressure. These characteristics are due to its (1) high porosity, (2) interconnected open pore structure and (3) tailorable membrane thickness. Although electro–spun membranes have been extensively studied for decades and successfully commercialized as air filtration membrane, they have not been applied for water treatment. The nanofiber membranes were used recently at the Industrial Membrane Research Laboratory of the University of Ottawa with the collaboration of Nanoscience & Nanotechnology Initiative of the National University of Singapore for the following investigations.Removal of latex particles from water: PVDF nanofiber membranes were subjected to filtration of latex particles (0.1 to 10 μm) at the feed pressure of 0.6 bar gauge [1, 2].Seawater desalination by membrane distillation: PVDF nanofiber membranes were subjected to desalination of aqueous NaCl solutions by air gap membrane distillation [3, 4].Trihalomethanes (THMs) and haloacetic acids (HAAs) removal by carbonized polyacrylnitrile (PAN) nanofiber membranes [5, 6].
New Composite Membrane of Carboxylated Polysulfone (CPS)– Polyphenylene Ether Ether Sulfone (PPEES) as Potential Material for Direct Methanol Fuel Cell
Authors: Hegde C. , Isloor A. M. , Belavadi G. , Kumar R.
Published: November 2018

In the present study, carboxylated polysulfone (CPS) and Poly (1,4–phenylene ether ether–sulfone) (PPEES) NF membranes for their application in proton exchange membrane fuel cells (PEMFCs) were investigated. New NF membranes were prepared by blending PPEES with CPS solution in NMP (5 wt. %) by the solution casting procedure using K–control coater. The membranes have been characterized by thermal analysis, water uptake, IEC measurements, proton conductivity performance and methanol crossover. Electrochemical impedance spectroscopy (EIS) was at length used to decide proton conductivity. The addition of CPS increased the water uptake capability of the synthesized membrane and resulted in enhanced proton conductivity. The conductivity values in the range of 10–4 –10–2 S/cm were obtained for the new CPS–PPEES membranes. The conductivities of the membranes showed increasing trend as a function of operating temperature and wt. % of CPS. Membrane of the type CM1 gave the conductivity in the range of 0.12 S/cm at 100°C. The results showed that, CPS/PPEES is a promising membrane material for possible use in proton exchange membrane fuel cells.
Permeate Flux in Ultrafiltration Membrane: A Review
Authors: Beicha A. , Zaamouch R. , Sulaiman N. M.
Published: November 2018

Membrane processes exist for most of the fluid separations encountered in industry. The most widely used is membrane ultrafiltration, pressure driven process which is capable of separating particles in the approximate size range of 0.001 to 0.1 μm. The design of membrane separation processes, like all other processes, requires quantitative expressions relating material properties to separation performance. The factors controlling the performance of ultrafiltration are extensively reviewed. There have been a number of seminal approaches in this field. Most have been based on the rate limiting effects of the concentration polarization of the separated particles at the membrane surface. Various rigorous, empirical and intuitive models exist, which have been critically assessed in terms of their predictive capability and applicability. The decision as to which of the membrane filtration models is the most correct in predicting permeation rates is a matter of difficulty and appears to depend on the nature of the dispersion to separated.
Evaluation of Bio-toxicity Removal by Two-Stage Membrane Bioreactor for Landfill Leachate Treatment
Authors: Boonyaroj V. , Chiemchaisri C. , Chiemchaisri W. , Yamamoto K.
Published: November 2018

Two-stage membrane bioreactor was applied to the treatment of municipal solid waste landfill leachate. This study aimed to evaluate the toxicity of treated leachate by this system. Bio-toxicity (acute and geno-toxicity) were conducted using O. niloticus and C. carpio. The lethal concentrations (LC50) of selected species exposed to raw leachate and treated leachate were investigated. Comet assay was utilized for evaluation of geno-toxicity potential of raw and treated leachate using carried out at the 10th percentile of lethal concentration (LC10) that obtained from the acute toxicity test. The relationship between pollutant concentrations i.e., NH3, COD and mortality were analyzed on Finney’s probit analysis. The results found that ammonia was the principal pollutants causingtoxicity in landfill leachate. Nevertheless, toxicity effect between ammonia and organic concentrations was also observed. The corresponding ammonia concentration causing 50% mortality of C. carpio and O. niloticus after96 hour exposure were 2.3-2.6 and 2.2-2.5 mg/l respectively. The sensitivity test of geno-toxicity effect at the level of DNA damage show that O. niloticus was considerably more sensitive to leachate. The membrane bioreactor system helps reducing toxic organic compounds and bio-toxicity on living organisms.
Characterization Study of PVDF/ Cloisite Hollow Fiber Membrane in Aqueous Diethanolamine
Authors: Naim R. , Abdullah S. , Zulkifli N.
Published: November 2018

Different concentrations of PVDF/Cloisite hollow fiber membranes were prepared and studied via immersion test. The differences in membrane properties were observed by immersion tests at 10 days, 20 days and 30 days in DEA solution. The membranes were characterized via liquid entry pressure (LEPW) and contact angle. Surface morphology analysis study was conducted before and after immersion test using scanning electron microscopy. From the result obtained, the liquid entry pressure and contact angle showed decreasing effect after immersion in DEA solution for 30 days. SEM analysis indicated that increasing DEA concentration creates more finger-like structure compared to pristine membrane. Incorporation of cloisite into PVDF membranes improves the contact angle value but development of more finger-like structure is subjected to wetting problem.
Effect of Sodium Hydroxide and Mould Shape in Geopolymer Fabrication Made With Synthesised Local Clay for Water Filtration
Authors: Bolong N. , Saad I. , Arshad S. E.
Published: November 2018

The preparation and testing of geopolymer ceramic membranes for water separation is presented. Geopolymers are typically used in refractories and as precursors to ceramic formation, allowing the production of ceramic-like materials with low temperature processes. A new geopolymer material was synthesized using local clay from Sabah, Malaysia and its filtration performance was compared to a commercial clay fabrication. The synthesized formulation of geopolymer ceramic paste was made by mixing local metakaolin clay as a source of aluminosilicate with alkaline solution, and then curing in a sealed environment. The amorphous paste was crushed and moulded prior to firing at an elevated temperature up to 700C. The feasibility of this laboratory-fabricated geopolymer for water filtration applications was studied by evaluating its performance at different thicknesses and mould shapes of fabricated membrane using 8 to 16 Molar natrium hydroxide (NaOH) as the alkali activator in the synthesis of the geopolymer. The result found that increased molarity of sodium hydroxide results higher compressive strength and affect filtration rate. Improved filtration performance (subject to the shape and width of the geopolymer membrane) was found by analysis and separation rates of 47% for blue dye colour and 88% for turbidity were achieved when operated without pressure or pump.
Study of the Effectiveness of Titanium Dioxide (TiO2) nanoparticle in Polyethersulfone (PES) Composite Membrane for Removal of Oil in Oily Wastewater
Authors: Shahruddin Munawar Zaman , Zakaria Nuratikah , Diana Junaidi Nurul Fattin , Alias Nur Hashimah , Othman Nur Hidayati
Published: November 2018

Polyethersulfone/Titanium oxide (PES/TiO2) composite membranes at various compositions of TiO2 nanoparticle (0, 0.1 and 0.5 wt. %) were prepared via phase inversion method. The prepared composite membranes were then tested for degradation process and separation process for oily wastewater. It was found that the addition of TiO2 that possess visible-light response activity led to an improvement of the membrane performances especially in photocatalytic activities. The membrane performances were also investigated by using liquid separation system in order to obtain the flux/permeation rate and also the percentage of oil removal by the membranes. The results indicate that the increment the amount of TiO2 nanoparticle in the composite membrane reduced the permeation flux. Further study has been made by characterizing the membranes in terms of contact angle, Field Emission Scanning Electron Microscope (FESEM), Fourier Transform Infrared Spectrometer (FTIR) and X-Ray Diffraction (XRD) analysis. The characterization results indicate that the TiO2 nanoparticles were uniformly mixed in the membrane. The increased of membrane hydrophilicity was demonstrated by the contact angle measurement. By adding TiO2, the membrane hydrophilicity was observed to be better than the neat PES composite membrane. Cross sectional images from FESEM also indicate that the addition of TiO2 nanoparticles help in increasing the macro-void of the membranes. Finally, a comparison between neat PES membrane and PES/TiO2 nanoparticle membrane proved that addition of TiO2 nanoparticle can be one of the ways to maximize the removal of oil.
Transport Behavior in Polymer-Inorganic Membrane: A Review
Authors: Nik Mustofar N. N. , Jaafar Juhana , Aziz M. , Ismail A. F. , A. Rahman Mukhlis , Othman M. H. D. , Yusof N. , Salleh W. N. W. , Aziz F. , Rosmi M. S.
Published: November 2018

The polymer–inorganic composite membrane has emerged as an alternative to improve the separation properties of polymer membranes because they possess properties of both organic and inorganic membranes such as good hydrophilicity, selectivity, permeability, mechanical strength, and thermal and chemical stability. A unique combination of organic and inorganic properties is believed could overcome the limitations of the pure polymeric membranes. Transport behavior of gases, vapours and liquids through polymer membranes are important in ultrafiltration, nanofiltration, pervaporation, gas separation and fuel cell applications. A better understanding of transport mechanisms in polymer-inorganic composite membranes is highly important in order to achieve significant achievement in the respective applications. This article provides a detailed review of current research in the field of transport phenomena on the transport behaviour of proton and methanol through the polymeric-inorganic by means of proton conductivity and methanol permeability.
Influence of Membrane Properties on Pineapple Wine Clarification and Fouling Behavior
Authors: Youravong W. , Phukdeekhong M. , Taksinpatanapong P.
Published: November 2018

The experiment was carried out to investigate the influence of membrane pore size and hydrophobicity on the quality of clarified pineapple wine and fouling characteristics, using stirred cell dead–end microfiltration. The test membranes were mixed cellulose acetate (MCE, pore size 0.45 and 0.22 μm), modified polyvinylidene fluoride (MPVDF, 0.22 μm) and polyethersulfone (PESF, 0.22 μm). It was found that all types of membrane successfully clarified the pineapple wine. The membrane pore size and hydrophobicity played an importance role in membrane fouling, both reversible and irreversible. Regarding the permeate flux and fouling, 0.45 μm MCE was the most suitable for pineapple wine clarification. However, intensive organoleptic test with pilot scale would be needed.
Hydrophilicity Enhancement of Metal Oxide Nanoparticles Incorporated Polysulfone Ultrafiltration Membrane
Authors: Sabri N. S. M. , Hasbullah H. , Said N. , Ibrahim N. , Kasmani R. M. , R. Ali R. , Rahman S. A.
Published: November 2018

Hydrophilicity property of membrane is a crucial feature in preventing fouling by most organic components including proteins. In this work, two different metal oxide nanoparticles were selected and their effects on hydrophilicity of polysulfone (PSf) flat sheet membrane for ultrafiltration were investigated. Addition of copper oxide (CuO) and iron oxide (Fe2O3) of 0.25 wt% concentration in N-methyl-2-pyrrolidone (NMP) were also compared to a neat PSf membrane. The membranes were prepared via dry-wet phase inversion technique with 18 wt% of PSf with 5 wt% polyvinylpyrrolidone (PVP). The physical and chemical properties of the prepared membranes were observed by contact angle measurements, porosity, average pore size and scanning electron microscope (SEM). The membranes permeation performance was also examined in term of pure water flux (PWF) and protein rejection by using bovine serum albumin (BSA) solution. Contact angle value of CuO/PSf obtained was 67.1° that was lower than the neat PSf membrane of 87.9° whereas 68.1° for Fe2O3/PSf indicating that metal oxides addition did enhance the membrane hydrophilicity with CuO was slightly better than Fe2O3. The reduction in contact angle ensured that the pure water flux through the membrane with metal oxide additive would improve as well. For CuO, the PWF increased to 159.3 Lm-2hr-1 from 81.3 Lm-2hr-1 of neat PSf, while Fe2O3 showed the PWF at 93.4 Lm-2hr-1. Morphological analyses displayed asymmetric membranes with narrow finger-like structure were formed in this study. A well-formed dense top layer indicated that the membrane would possess good BSA rejection property with 92% of rejection achieved by CuO/PSf membrane. The incorporation of nanoparticles with the membrane is proven to be an effective mean to increase the membrane hydrophilicity with improved water flux and BSA rejection.
A Quantitative Structure Activity Relationship Study on Permeation of Amino Acids in Enantioselective Membranes
Authors: Hazarika S. , Dutta N. N. , Rao P. G.
Published: November 2018

The permeation of seven isomers of amino acids (AA) namely Tryptophan (Trp), Phenylalanine (Phe), Tyrosine (Tyr), Phenylglycine (Phegly), Methionine (Meth), Threonine (Thr)and Serine (Ser) was studied using an enantioselective membrane prepared from polysulphone containing L-tryptophan-glutaraldehyde condensation product in the polymer matrix. The experiments were conducted in dialysis mode under optimized condition of the aqueous phase pH and salt concentration in a two compartment membrane cell. The membrane was found to exhibit selectivity towards all the D-isomers of amino acids studied in this work. In order to deduce implication on the design of suitable membrane system for specific application, a quantitative structure activity relationship analysishas been made using hydrophobicity as the molecular descriptor. In this analysis, the solute fluxes were analysed on the basis of a permeation model consisting of diffusing flow alone. Finally, the model parameters of the diffusiveflux of both isomers were correlated with hydrophobicity taken as the molecular property.
Performance Study of Thin Film Composite Polyamide Membranes in Remediation of Nitro–phenols from Water
Authors: Yogesh K. , Popat K. M. , Brahmbhatt H. R. , Ganguly B. , Bhattacharya A.
Published: November 2018

Apart from the desalination activities, polyamide membranes spread their wings in different separation arena (viz.removal of organic pollutants, pesticides). The separation abilities of the membranes are basically involved in their compositions as well as nature of the solutes. The study brings to light that the removal of the two isomers of the nitrophenols are based on their orientation (viz. dipolemoment). The prepared membrane compositions are also very interesting to study to be dealt herewith. Molecular sizes and their dipole moments of the corresponding nitrophenols are calculated by quantum chemical method. The rejection performance of the phenol compounds for the same membranes are in the following order: 2–nitro phenol > 4–nitro phenol > phenol.
Experimental Evaluation of a Novel Backflush Controller for Immersed Membrane Systems
Authors: Erdei L. , Vigneswaran S. , Smith P. J.
Published: November 2018

Membrane backflush with air or permeate is commonly employed to reduce fouling in immersed micro– and ultrafiltration (MF/UF). Membrane plants traditionally rely on simple timer control automation to initiate periodic backflushes for membrane cleaning. In this study, a closed–loop (feedback) type backflush controller was evaluated experimentally with a bench–scale hollow fibre immersed MF/UF membrane – flocculation hybrid system.The controller showed an unexpected behaviour at low fouling rates, which was manifested in significantly varying filtration periods. The investigation identified the cause in the use of a constant stabilisation lag parameter.The role of this control parameter was to determine the reversible component of fouling in real–time, which is a difficult problem in transient flow conditions that characterise the start of filtration periods. The resulting error became significant at low fouling rates and impaired effective control.Based on this insight, we propose alternative, more robust control parameters, which can provide improved backwash control solutions for MF/UF membrane applications.
Cellulose and Chitosan Composite Membranes for Protein and Salt Filtration
Authors: Rakbamrung P. , Wanichapichart P. , Tirawanichakul Y.
Published: November 2018

Cellulose membrane (SE) was prepared by culturing Acetobacter xylinum in a media with sucrose as a carbon source and was used as a supporting membrane in this study. Pore size of the supporting membrane was studied by means of molecular weight cut off (MWCO) and SEM micrographs. For making cellulose/chitosan composite membrane SE/CH, chitosan solution was used as a coating polymer and applied by a casting method.This resulted in a smaller hydraulic permeability coefficient (Lp) from 6.7 × 10–11 m3 N–1 s–1 in membrane SE to 1.94 × 10–12 m3 N–1 s–1 in the composite membrane SE/CH. Using PEG of several molecular weights as feed solution, the MWCO of the SE membrane was 200 kDa while that of the SE/CH membrane was 6 kDa. The former rejected 1 g L–1 BSA by 80%. With pH between 3 and 8, the composite membrane SE/CH rejected NaCl and NaHCO3 by 50%, independent of the pH level. However, when using a divalent salt solution of MgSO4 the rejection was increased up to 85%, with an optimum at pH 6–7 and a permeate flux of 5.0 L m–2h–1 at pressures of 0.5 MPa.
Effect of Jet Stretch in the Fabrication of Polyethersulfone Hollow Fiber Spinning for Water Separation
Authors: Bolong N. , Ismail A. F. , Salim M. R.
Published: November 2018

The effect of jet stretch on the morphology, pure water permeation and sodium chloride rejection of hollow fiber membranes is analyzed by varying the spinning take up speed. Polyethersulfone hollow fibers were spun using dry–wet spinning technique. The membrane formulation of PES/NMP/Water/PVPk10 is spun at constant extrusion rate of 3.0 cm3/ min. The fiber take up speed during spinning varied from 19.7 to 29.5 cms–1, revealed that the flux of hollow fiber membranes is minimal when the fiber take up speed is equivalent to the velocity of dope extrusion. At low jet stretch, the permeability of membranes is high with elevated ionic solutes rejection produced. The influence of elongation stress towards hollow fiber membranes morphology and its performance for water separation is also highlighted.
Specific Anaerobic Fluidized Bed Bioreactors as Pretreatment to Microfiltration in Domestic Wastewater Treatment for Reuse
Authors: Xing W. , Guo W. S. , Ngo H. H. , Listowski A. , Cullum P.
Published: November 2018

Practical use of an anaerobic granular activated carbon (GAC) fluidized bed bioreactor (FBBR) as pretreatment to microfiltration was experimentally verified. A nature starch based cationic flocculants (GF) was employed in this study for testifying its impact on the performance of GAC–FBBR. The GAC–FBBR with and without addition of GF was evaluated in terms of dissolved organic carbon (DOC) removal from biologically treated sewage effluent (BTSE). With only a daily addition of 200 mg GF to GAC– FBBR and a depth of GAC of 500 mm, the biomass of GAC increased from 1.5 g/L to 4.2 g/L within operation period of 30 days while the system resulted in 5% better DOC removal. The results indicate that the GAC–FBBR as pretreatment could effectively remove the dissolved organics and improve the critical flux. Compared with the critical flux of BTSE with submerged microfiltration (SMF) alone (20 L/m2.h), the pretreatment by GAC–FBBR successfully increased the critical flux to 30 L/m2.h. Moreover, the addition of GF into GAC–FBBR could help in raising the critical flux to 35 L/m2.h.
Effect of DEA in Membrane Gas Absorption System Using Polymeric Flat Sheet Membrane
Authors: Ahmad A. L. , Sunarti A. R. , Lee K. T. , Fernando W. J. N.
Published: November 2018

The objective of this study was to investigate the potential process of the removal of carbon dioxide (CO2) from flue gases by using developed membrane gas absorption system. The experiments were performed in membrane gas absorption system consisted 0.45 μm pore size microporous polyvinylidenefluoride (PVDF) flat sheet membrane. Diethanolamine (DEA) solution was employed as the liquid absorbent. The operating parameters such as the gas and liquid flow rate were setup at 100 cm3/min and 25 cm3/min and liquid absorbent was at room temperature. The effect of DEA concentration was studied with variation in range 1 M to 5 M. In addition, the experiments were carried out with 20%, 40% and 100% gas ratio CO2 to N2. The results show that hydrophobic polymeric membranes such as PVDF can be efficiently used for gas absorption with optimized concentration of DEA.
Treatment of Septic Tank Effluent by Membrane Bioreactor: A Laboratory–scale Feasibility Study
Authors: Chang C–Y. , Ben Aim Roger , Vigneswaran S. , Chang J–S. , Chen S–L.
Published: November 2018

A laboratory scale membrane bioreactor (MBR) fed on real septic tank effluent was studied at different levels of alkalinity (0, 250 and 500 mg NaHCO3/L addition) and sludge retention time (SRT, complete sludge retention, 10 and 20 days). A long–term operation of 267 days was divided into 5 stages to examine the SRT and alkalinity influences on parameters related to nitrification, chemical oxygen demand (COD) removal, extracellular polymeric substances (EPS) production and membrane cleaning. The results of the study showed that the removals of TCOD, SCOD and NH4+–N varied between 86–94%, 71–86%, and 70–94%, respectively. Appropriate alkalinity supplement and SRT control can enhance the COD removal and nitrification. Irreversible membrane fouling occurred fast and water cleaning for the improvement of filtration capacity was ineffective. The results also revealed that the rejection of EPS played a major role both in the enhancement of removal efficiency as well as the increase of filtration resistance during the operation.
Preliminary Study of Hospital Wastewater Treatment with a Submerged Membrane Bioreactor (SMBR): Case Study of Songklanagarind Hospital – Thailand
Authors: Preecha U. , Sridang P. , Wanichapichart P.
Published: November 2018

The objective of this research was to study hospital wastewater treatment using a submerged membrane bioreactor (SMBR). The lab scale unit of SMBR with a working volume of 20 liters was operated at a hydraulic retention time of 0.416 day and 0.208 day at F/M ratio of 0.18 day–1 and 0.29 day–1. The operating conditions were set up to provide good biological treatment without sludge extraction, and two different permeate flux values were studied. The performance of membrane was studied by monitoring the variation of transmenbrane pressure (TMP) during filtration runs. The efficiency of MBR was investigated according to the daily measurements of pH, dissolved oxygen and temperature. The COD, BOD5, NH4+–N, TKN, color, turbidity, SS and Escherichia coli (E.coli) in influent and effluent were analyzed. Membrane fouling intensity occurred slowly when the system operated with flux at 10 L/h/m2 and 20 L/h/m2, which induced high TMP at the initial period of filtration. The fouling rate was at about 0.3022 mbar/day for the permeation of flux at 10 L /h/m2. The fouling rate still remained at 0.2774 mbar/day for 20 L/h/m2. The results showed the great effect of membrane use for total biomass retention and the removal rate of COD, BOD5 and E.coli were over 90%. The characteristics of sludge in SMBR showed healthy floc formations with good settling. Although the ratio of MLVSS/MLSS was lower than the normal range (about 0.2), it was found that the average values of COD and NH4+–N in permeate were lower than 2–80 mg/L and 0.05–6.755 mg/L while the value of turbidity was also less than 3 NTU.
Grafting of Poly(2–hydroxyethyl methacrylate) on Natural Rubber (NR–g–PHEMA): Characterizations and Water Sorption Selectivity of NR–g–PHEMA Membranes
Authors: Ratphonsan P. , Poonsawat C. , Khansawai P. , Amnuaypanich S.
Published: November 2018

Poly(2–hydroxyethyl methacrylate) (PHEMA) was grafted onto NR latex particles employing emulsion polymerization technique. Grafting efficiency (%GE) of PHEMA on NR particles was found to increase with increasing 2–hydroxyethyl methacrylate monomer (HEMA). Differently, %GE increased rapidly at low initiator concentrations before leveling off at higher concentrations. The NR–g–PHEMA latex was cast into a thin membranes. The membranes were subjected to the tensile testing. The Young’s modulus of NR–g–PHEMA membrane was found to improved as %GE increased in contrast to the elongation at break. Revealing by DSC, the states of water in the NR–g–PHEMA membranes appeared as the free water and non–freezing bound water and both increased with %GE. Swelling behavior of NR–g–PHEMA membranes in water–acetone mixtures was investigated. The membrane swelling showed a non–ideal behavior where a maximum swelling degree was found at certain concentrations of water–acetone mixtures. The water sorption selectivity of the membranes was enhanced when increasing %GE for low water content in the water–acetone mixtures. However, as increasing water content, the water sorption selectivity was declined.
Ih contributes to increased motoneuron excitability in restless legs syndrome
Authors: Czesnik Dirk , Howells James , Bartl Michael , Veiz Elisabeth , Ketzler Rebecca , Kemmet Olga , Walters Arthur S. , Trenkwalder Claudia , Burke David , Paulus Walter
Published: November 2018

Key points

Restless legs patients complain about sensory and motor symptoms leading to sleep disturbances. Symptoms include painful sensations, an urge to move and involuntary leg movements.

The responsible mechanisms of restless legs syndrome are still not known, although current studies indicate an increased neuronal network excitability. Reflex studies indicate the involvement of spinal structures. Peripheral mechanisms have not been investigated so far.

In the present study, we provide evidence of increased hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channel‐mediated inward rectification in motor axons. The excitability of sensory axons was not changed.

We conclude that, in restless legs syndrome, an increased HCN current in motoneurons may play a pathophysiological role, such that these channels could represent a valuable target for pharmaceutical intervention.

Restless legs syndrome is a sensorimotor network disorder. So far, the responsible pathophysiological mechanisms are poorly understood. In the present study, we provide evidence that the excitability of peripheral motoneurons contributes to the pathophysiology of restless legs syndrome. In vivo excitability studies on motor and sensory axons of the median nerve were performed on patients with idiopathic restless legs syndrome (iRLS) who were not currently on treatment. The iRLS patients had greater accommodation in motor but not sensory axons to long‐lasting hyperpolarization compared to age‐matched healthy subjects, indicating greater inward rectification in iRLS. The most reasonable explanation is that hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels open at less hyperpolarized membrane potentials, a view supported by mathematical modelling. The half‐activation potential for HCN channels (Bq) was the single best parameter that accounted for the difference between normal controls and iRLS data. A 6 mV depolarization of Bq reduced the discrepancy between the normal control model and the iRLS data by 92.1%. Taken together, our results suggest an increase in the excitability of motor units in iRLS that could enhance the likelihood of leg movements. The abnormal axonal properties are consistent with other findings indicating that the peripheral system is part of the network involved in iRLS.
Obesity gives unexpected boost to anticancer drugs
Authors: Kaiser Jocelyn
Published: November 2018

Drugs revive immune cells exhausted by obesity hormone.
Response to Comment on “Predicting reaction performance in C–N cross-coupling using machine learning”
Authors: Estrada Jesús G. , Ahneman Derek T. , Sheridan Robert P. , Dreher Spencer D. , Doyle Abigail G.
Published: November 2018

We demonstrate that the chemical-feature model described in our original paper is distinguishable from the nongeneralizable models introduced by Chuang and Keiser. Furthermore, the chemical-feature model significantly outperforms these models in out-of-sample predictions, justifying the use of chemical featurization from which machine learning models can extract meaningful patterns in the dataset, as originally described.
Polarimetry enabled by nanophotonics
Authors: Martínez Alejandro
Published: November 2018

Nanoantenna and plasmonic structures can be used to measure light polarization
A physicist's final reflections
Brief Answers to the Big Questions
Stephen Hawking
Bantam Press, 2018. 255 pp.
Authors: Robinson Andrew
Published: November 2018

An unfinished tome reveals the late Stephen Hawking's musings on life's biggest mysteries
A Hypothesis-Generating Study of the Combination of Aspirin plus Macrolides in Patients with Severe Community-Acquired Pneumonia
Authors: Falcone Marco , Russo Alessandro , Shindo Yuichiro , Farcomeni Alessio , Pieralli Filippo , Cangemi Roberto , Liu Jinliang , Xia Jingyan , Okumura Junya , Sano Masahiro , Jones Christopher , Vannucchi Vieri , Mancone Massimo , Micek Scott , Xu Feng , Violi Francesco , Kollef Marin
Published: November 2018

While the inflammatory response to severe pneumonia is paramount in limiting and resolving the infection, excessive inflammation can lead to deleterious effects. We theorized that patients with severe community-acquired pneumonia (CAP) who were treated with macrolides and aspirin would receive benefit beyond that of conventional antibiotic therapy.
Impact of Antifungal Compounds on Viability and Anti-
Aspergillus
Activity of Human Natural Killer Cells
Authors: Schmidt Stanislaw , Schubert Ralf , Tramsen Lars , Lehrnbecher Thomas
Published: November 2018

Despite the availability of new antifungal compounds, invasive aspergillosis carries high morbidity and mortality in hematopoietic stem cell transplant recipients.
In vitro
studies and animal models suggest that the adoptive transfer of natural killer (NK) cells might be a promising immunotherapeutic option in this setting.
Metabolites of an Oil Field Sulfide-Oxidizing, Nitrate-Reducing
Sulfurimonas
sp. Cause Severe Corrosion
Authors: Lahme Sven , Enning Dennis , Callbeck Cameron M. , Menendez Vega Demelza , Curtis Thomas P. , Head Ian M. , Hubert Casey R. J.
Published: November 2018

Ambiguous reports of corrosion problems associated with the injection of nitrate for souring control necessitate a deeper understanding of this frequently applied bioengineering strategy. Sulfide-oxidizing, nitrate-reducing bacteria have been proposed as key culprits, despite the underlying microbial corrosion mechanisms remaining insufficiently understood. This study provides a comprehensive characterization of how individual metabolic intermediates of the microbial nitrogen and sulfur cycles can impact the integrity of carbon steel infrastructure. The results help explain the dramatic increases seen at times in corrosion rates observed during nitrate injection in field and laboratory trials and point to strategies for reducing adverse integrity-related side effects of nitrate-based souring mitigation.
Diversity in CO
2
-Concentrating Mechanisms among Chemolithoautotrophs from the Genera
Hydrogenovibrio
,
Thiomicrorhabdus
, and
Thiomicrospira
, Ubiquitous in Sulfidic Habitats Worldwide
Authors: Scott Kathleen M. , Leonard Juliana M. , Boden Rich , Chaput Dale , Dennison Clare , Haller Edward , Harmer Tara L. , Anderson Abigail , Arnold Tiffany , Budenstein Samantha , Brown Rikki , Brand Juan , Byers Jacob , Calarco Jeanette , Campbell Timothy , Carter Erica , Chase Max , Cole Montana , Dwyer Deandra , Grasham Jonathon , Hanni Christopher , Hazle Ashlee , Johnson Cody , Johnson Ryan , Kirby Brandi , Lewis Katherine , Neumann Brianna , Nguyen Tracy , Nino Charari Jonathon , Morakinyo Ooreoluwa , Olsson Bengt , Roundtree Shanetta , Skjerve Emily , Ubaldini Ashley , Whittaker Robert
Published: November 2018

Autotrophic organisms take up and fix DIC, introducing carbon into the biological portion of the global carbon cycle. The mechanisms for DIC uptake and fixation by autotrophic
Bacteria
and
Archaea
are likely to be diverse but have been well characterized only for “
Cyanobacteria
.” Based on genome sequences, members of the genera
Hydrogenovibrio
,
Thiomicrospira
, and
Thiomicrorhabdus
have a variety of mechanisms for DIC uptake and fixation. We verified that most of these organisms are capable of growing under low-DIC conditions, when they upregulate carboxysome loci and transporter genes collocated with these loci on their chromosomes. When these genes, which fall into four evolutionarily independent families of transporters, are expressed in
E. coli
, DIC transport is detected. This expansion in known DIC transporters across four families, from organisms from a variety of environments, provides insight into the ecophysiology of autotrophs, as well as a toolkit for engineering microorganisms for carbon-neutral biochemistries of industrial importance.
Salmonella enterica Filamentation Induced by Pelargonic Acid Is a Transient Morphotype
Authors: Dev Kumar Govindaraj , Macarisin Dumitru , Micallef Shirley A.
Published: November 2018

Some bacteria form elongated multinucleated structures, or filaments, when exposed to stress. The filamentous form of foodborne bacterial pathogens can interfere with food protection practices and diagnostic testing. Filamentation in
Salmonella enterica
Newport was investigated in response to pelargonic acid, a compound naturally found in several fruit and vegetables, and also used commercially as an herbicide.
Salmonella
readily formed filaments when exposed to pelargonic acid. Filaments were not stable, however, and fragmented to individual cells even when the fatty acid was still present, recovering fully when the stress was alleviated. A deeper exploration of the molecular mechanisms regulating filamentation and the conditions that induce it in agriculture and the food supply chain is needed to devise strategies that curb this response.
Distinct Modes of Promoter Recognition by Two Iron Starvation σ Factors with Overlapping Promoter Specificities
Authors: Agnoli Kirsty , Haldipurkar Sayali S. , Tang Yingzhi , Butt Aaron T. , Thomas Mark S.
Published: November 2018

ECF σ factors regulate subsets of bacterial genes in response to environmental stress signals by directing RNA polymerase to promoter sequences known as the −35 and −10 elements. In this work, we identify the −10 and −35 elements that are recognized by the ECF σ factor OrbS. Furthermore, we demonstrate that efficient promoter utilization by this σ factor also requires a polyadenine tract located downstream of the −35 region. We propose that the unique architecture of A-tract DNA imposes conformational features on the −35 element that facilitates efficient recognition by OrbS. Our results show that sequences located between the core promoter elements can make major contributions to promoter recognition by some ECF σ factors.