[Effect of positive end-expiratory pressure on the cross-sectional area of the internal jugular vein and anatomic relationship between the internal jugular vein and the carotid artery in general anaesthesia of laryngeal mask airway]

Objective: To investigate the effect of positive end-expiratory pressure(PEEP) on the cross-sectional area (CSA) of the internal jugular vein (IJV) and anatomic relationship between the IJV and the common carotid artery (CCA) in general anaesthesia of laryngeal mask airway(LMA). Methods: Sixty American Society of Anesthesiologists (ASA) Ⅰ or Ⅱ grade patients undergoing elective operation received general anaesthesia using LMA from May to November 2017, aged 20-65, were included in this study and randomly divided into 4 groups: group P0 (PEEP: 0 cmH(2)O), group P5 (PEEP: 5 cmH(2)O), group P10 (PEEP: 10 cmH(2)O), group P15 (PEEP: 15 cmH(2)O). Following the induction of anesthesia, LMA was inserted, and mechanical ventilation was started while the right cervical vessels was imaged by ultrasonography after applying 4 different PEEPs in random order. Measurements were made after 1 min in each PEEP. The CSA, transverse diameter (TD), anteroposterior diameters (AD) of the IJV and the diameter, overlap distance and overlap index of CCA was measured. The arterial blood pressure, heart rate, and vasoactive drugs used were also recorded. Results: The CSA of group P0, P10 and P15 was (1.36±0.55), (1.80±0.54), (2.02±0.58) cm(2). The TD was (1.31±0.33), (1.61±0.49), (1.74±0.53) cm. The AD was (1.12±0.20), (1.33±0.30), (1.46±0.32) cm. Compared to group P0, the CSA, TD and AD of IJV in group P10 and P15 were significantly increased (P0/P10: t=7.81, 3.81, 4.30, all P<0.01; P0/P15: t=11.68, 5.40, 6.96, all P<0.01). There was no significant difference in the AD and TD of IJV between group P10 and P15 (all P>0.05), while the CSA of group P15 was bigger than that of group P10 (t=2.17, P<0.05). The overlap distance of group P0, P10 and P15 was (0.51±0.12), (0.62±0.16), (0.66±0.15) cm. The overlap index was (76.80±20.03)%, (91.10±26.13)%, (96.21±25.36)%. Compared to group P0, the overlap distance and overlap index in group P10 and P15 were significantly increased (P0/P10: t=4.49, 3.41, both P<0.01; P0/P15: t=5.91, 4.63, both P<0.01). There was no significant changes in the overlap distance and overlap index between group P10 and P15 (all P>0.05). The MAP of group P15 was lower than that of group P10 [(73.35±9.73 )vs (67.58±12.58) mmHg, t=2.745, P<0.05]. No patients were given atropine or norepinephrine. Conclusions: The application of PEEP effectively increases the CSA of IJV in general anaesthesia of LMA. At the same time, it also lead to higher overlap index between the IJV and CCA.Ten cmH(2)O PEEP provides the best balance between the increase of CSA and the stability of haemodynamics.

[Effects of lappaconitine on intraoperative administration of remifentanil induced postoperative hyperalgesia in general anaesthesia patients]

Objective: To explore the effects of lappaconitine on intraoperative administration of remifentanil induced postoperative hyperalgesia in general anaesthesia patients. Methods: One hundred and twenty patients from March to October 2016 undergoing elective thyroid operation under general anaesthesia at Ningbo NO.2 hospital, American Society of Anesthesiologists(ASA) Ⅰ or Ⅱ grade, aged 20-60, were enrolled in this study and randomly assigned to 3 groups (n=40). Remifentanil was intraoperatively infused at 0.1 μg·kg(-1)·min(-1) (Group S) or 0.3 μg·kg(-1)·min(-1) (Groups L and G), and patients in group G received lappaconitine 8 mg 30 minutes before the ending of surgery. Mechanical pain thresholds, visual analogue scale (VAS) and additional analgesics were recorded at 2, 6 and 24 hours after the operation. Results: There was no significant difference among the VAS and additional analgesics in three groups at 2, 6 and 24 h after operation (all P>0.05). There was no significant difference among the mechanical pain thresholds in three groups before and 2 h after operation (all P>0.05). The mechanical pain thresholds of group S, L and G was (45.7±15.6), (35.8±15.0), (47.6±16.4)g at 6 h and (50.7±17.0), (33.7±14.0), (49.7±13.9 )g at 24 h after operation. There was significant difference among the mechanical pain thresholds in group S, L and G at 6 h and 24 h after operation (F=6.586, 16.089, all P<0.01). Compared to group S, the mechanical pain thresholds significantly decreased in group L at 6 h and 24 h after operation (q=2.837, 5.045, all P<0.01). While there was a significantly increase in pain thresholds at 6 h and 24 h postoperatively in group G, as compared with the group L (q=3.384, 4.770, all P<0.01). Conclusion: Lappaconitine significantly alleviated intraoperative administration of remifentanil induced postoperative hyperalgesia in general anaesthesia patients.

Microplastics in freshwater systems: A review on occurrence, environmental effects, and methods for microplastics detection

The continuous increase in synthetic plastic production and poor management in plastic waste have led to a tremendous increase in the dumping into our aqueous environment. Consequently, microplastics commonly defined as sizes less than 5 mm are produced and stay in both seawater and freshwater environment. The presence of microplastics as a new type of emerging contaminant has become a great issue of concerns from public and government authorities. The sources of microplastics to freshwater systems are many with the largest portion from wastewater treatment plants. The abundance of microplastics varies with the location, from above 1 million pieces per cubic meter to less than 1 piece in 100 cubic meters. Microplastics can cause several harmful physical effects on humans and living organisms through such mechanisms as entanglement and ingestion. The microplastics can act as carriers of various toxins such as additives from industrial production processes and persistent contaminants by the sorption in waters. Those toxins may cause great health problems to humans. A few studies on the fishes demonstrated that the microplastics and the associated toxins are bio-accumulated and cause such problems as intestinal damage and change in metabolic profiles. In studies of microplastics, fresh water is first sampled by the nets with typical mesh size of 330 μm for collection of microplastics. After the volume reducing process, the samples will then go through the purification process including density separation by such inorganic salts as sodium chloride and digestion process by oxidizing agents or enzymes. The sequence of these two processes (namely purification and digestion) is dependent on the sample type. The purified samples can be studied by several analytical methods. The commonly used methods for the qualification studies are FTIR spectroscopy, Raman spectroscopy, pyrolysis-GC/MS, and liquid chromatography. A tagging method can be used in the quantification study. Our literature study finds that there is still no universal accepted quantification and qualification tools of microplastics in fresh waters. More work is anticipated so as to obtain accurate information on microplastics in freshwater, which can then be used for the better assessment of the environmental risk.

Degradation of organic compounds during the corrosion of ZVI by hydrogen peroxide at neutral pH: Kinetics, mechanisms and effect of corrosion promoting and inhibiting ions

The corrosion of zero valent iron (ZVI) by hydrogen peroxide (H₂O₂) generates hydroxyl (⋅OH) and other radical oxygen species (ROS) that degrade organic materials. To better understand the factors that govern the ROS formation during the H₂O₂-induced corrosion, we investigated the degradation of an organic probe compound (acesulfame (ACE)) in slurries of ZVI powder in unbuffered laboratory water at pH 6.5 ± 0.5. Chloride ions accelerated the corrosion of ZVI by H₂O₂ and the formation ROS and, therefore, the degradation of organic materials. Conversely, slowing corrosion by phosphate buffer inhibited ROS formation and the degradation of organic compounds. The rate of H₂O₂ decomposition was correlated with the liberation of Fe²⁺(aq) and the ACE degradation rate. The kinetics of H₂O₂ decomposition was pseudo-first-order and zero-order at low (<0.04 mM/mg) and high [H₂O₂]/[ZVI] initial ratios, respectively, and was consistent with Langmuir kinetics. The H₂O₂ decomposition rate was proportional to the ZVI reactive surface area (SA) and nearly independent of the extent of ZVI oxidation, the presence of a Fe²⁺(aq) chelating agent, and ⋅OH quenchers (methanol and tert-butanol). Kinetic data suggest a mechanism involving rapid cathodic reduction of H₂O₂ at the metallic ZVI surface which causes the liberation of Fe²⁺(aq) that generate ⋅OH via the homogeneous Fenton reaction. The stoichiometric efficiency (SE) of organics degradation ranged from 0.0008% to 0.014% and increased with decreasing H₂O₂ decomposition rate.

DNA hydroxymethylation rate in the AChE and HoxC4 promoter associated with human sperm quality

The relationship of altered DNA 5'-hydroxymethylation in human spermatozoa with seminal parameters remains unclear. The aim of the study was to investigate the association between the 5'-hydroxymethylcytosine (5hmC) rate in the promoters of acetylcholinesterase (AChE) and homeobox C4 (HoxC4) genes and human sperm concentration/motility. The study population consisted of three groups: asthenozoospermia (AZ), oligoasthenozoospermia (OAZ) and normozoospermia (NZ). The 5hmC rate in the promoter was measured by CCGG loci-dependent MspI/HpaII restriction mapping of glycosylation-modified sperm DNA combined with a hydroxymethylation-specific real-time polymerase chain reaction assay. The 5hmC rate in the AChE promoter in group AZ and OAZ was higher than that in group NZ (p < .05). A weak inverse correlation between 5hmC rate of AChE and sperm motility was observed in all subjects (r = -.172, p < .05). The 5hmC rate in the HoxC4 promoter in group OAZ was lower than that in group NZ (p < .05). These results indicated that altered 5hmC rates of AChE and HoxC4 promoters are associated with low sperm motility and sperm concentration respectively.

Development of a novel biochar/PSF mixed matrix membrane and study of key parameters in treatment of copper and lead contaminated water

Mixed matrix membrane (MMM) has attracted increasing attentions in various applications, such as water treatment. In this study, an innovative biochar/polysulfone (PSF) mixed matrix hollow fiber membrane was fabricated by incorporating micro-sized biochar particles in the PSF matrix. It was demonstrated that the membrane was more hydrophilic than the pure PSF membrane. Higher water flux was obtained. The adsorption of copper and lead on the MMM increased as the pH was increased with the maximum adsorption capacity observed at pH > 4.5. The adsorption equilibrium was established in 7 and 12 h for lead and copper, respectively. The adsorption kinetics and isotherm followed the intraparticle surface diffusion model and Freundlich isotherm, respectively. The presence of humic acid (HA) had a little effect on the adsorption, while the ionic strength showed an adverse effect on the removal. In addition, the feed concentration and cross flow rate significantly affected the removal efficiency in a continuous filtration mode. The increase in feed concentration and cross flow rate resulted in a reduction in the volume of treated permeate that had the copper/lead concentrations below the regulated levels for drinking water. The MMM exhibited an excellent regeneration-reuse performance in the removal of both copper and lead. Finally, our mechanism studies indicated that the uptake of heavy metals was controlled by a combination of key reactions of complexation, ion-exchange and precipitation. This study indicated that the MMM can be applied as an effective and eco-friendly material for the treatment of heavy metals contaminated water.

[Influence of aluminum chloride exposure on embryonic development of zebrafish and neurobehavior of juvenile fish]

Objective: To investigate the influence of aluminum chloride (AlCl(3)) solution on the embryon-ic development of zebrafish and neurobehavior of juvenile fish. Methods: The embryos of zebrafishat 6 hours after fertilization were exposed to AlCl(3) solution at a concentration of 0, 55.0, 60.5, 66.6, 73.5, 80.5, or 100.0 mg/L, and embryonic hatching rates at 48 and 72 hours after fertilization were calculated. The embryos of zebrafishat 6 hours after fertilization were exposed to AlCl(3) solution at a concentration of 0, 60.0, 72.0, 86.4, 103.7, or 124.4 mg/L, and the embryonic mortality rates at 12, 24, 48, 72, and 96 hours after fertilization were calculat-ed. The embryos of zebrafish at 6 hours after fertilization were exposed to AlCl(3) solution at a concentration of 0, 50, 100, 200, 400, or 800 μg/L, and the changes in the neurobehavior of juvenile fish were observed after hatching, including touch-escape reaction at 72 hours after fertilization and autonomic movement and panic es-cape reflex at 7 days after fertilization. Results: Compared with the 0 mg/L group, the≥66.6 mg/L group had a sig-nificant reduction in embryonic hatching rate at 48 and 72 hours after fertilization, and the ≥72.0 mg/L group had a significant increase in embryonic mortality rate at 96 hours after fertilization (P<0.05) . Compared with the 0 μg/L group, the≥100 μg/L group had a significant reduction in the number of times of touch-escape reaction (P<0.05) .Compared with the 0 and 50 μg/L groups, the 100-800 μg/L groups had significant reductions in total movement distance and average speed (P<0.05) . Compared with the dark period before illumination, all groups had a significant increase in movement speed during the light period of the panic escape reflex test (i.e., the third minute) (P<0.05) ; within 2 minutes after the light was turned off, there was no significant change in movement speed in the 0-200 μg/L groups (P>0.05) ; the 400 and 800 μg/L groups had a significant increase in movement speed (P<0.05) . Conclusion: AlCl(3) exposure may cause embryonic developmental disorder in zebrafish and ab-normal neurobehavior in juvenile fish.

Treatment of lead contaminated water by a PVDF membrane that is modified by zirconium, phosphate and PVA

Lead contamination is one of the most serious problems in drinking water facing humans. In this study, a novel zirconium phosphate modified polyvinyl alcohol (PVA)-PVDF membrane was developed for lead removal. The zirconium ions and PVA were firstly coated onto a PVDF membrane through crosslinking reactions with glutaraldehyde, which was then modified by phosphate. The adsorption kinetics study showed that most of ultimate uptake occurred in 5 h. The adsorption increased with an increase in pH; the optimal adsorption was achieved at pH 5.5. The experimental data were better described by Langmuir equation than Freundlich equation; the maximum adsorption capacity was 121.2 mg-Pb/g at pH 5.5, much higher than other reported adsorptive membranes. The membrane exhibited a higher selectivity for lead over zinc with a relative selectivity coefficient (Pb(2+)/Zn(2+)) of 9.92. The filtration study showed that the membrane with an area of 12.56 cm(2) could treat 13.9 L (equivalent to 73,000 bed volumes) of lead containing wastewater with an influent concentration of 224.5 μ g/L to meet the maximum contaminant level of 15 μ g/L. It was demonstrated that the membrane did well in the removal of lead in both simulated wastewater and lead-spiked reservoir water and had a good reusability in its applications. The XPS studies revealed that the lead uptake was mainly due to cation exchange between hydrogen ions and lead ions.

Exotic skyrmion crystals in chiral magnets with compass anisotropy

The compass-type anisotropy appears naturally in diverse physical contexts with strong spin-orbit coupling (SOC) such as transition metal oxides and cold atomic gases etc, and it has been receiving substantial attention. Motivated by recent studies and particularly recent experimental observations on helimagnet MnGe, we investigate the critical roles of this compass-type anisotropy in modulating various spin textures of chiral magnets with strong SOC, by Monte Carlo simulations based on a classical Heisenberg spin model with Dzyaloshinsky-Moriya interaction and compass anisotropy. A phase diagram with emergent spin orders in the space of compass anisotropy and out-of-plane magnetic field is presented. In this phase diagram, we propose that a hybrid super-crystal structure consisting of alternating half-skyrmion and half-anti-skyrmion is the possible zero-field ground state of MnGe. The simulated evolution of the spin structure driven by magnetic field is in good accordance with experimental observations on MnGe. Therefore, this Heisenberg spin model successfully captures the main physics responsible for the magnetic structures in MnGe, and the present work may also be instructive to research on the magnetic states in other systems with strong SOC.

Zirconium/polyvinyl alcohol modified flat-sheet polyvinyldene fluoride membrane for decontamination of arsenic: Material design and optimization, study of mechanisms, and application prospects

Arsenic contamination in industrial wastewater and groundwater has become an important environmental issue. In this study, a novel zirconium/polyvinyl alcohol (PVA) modified polyvinyldene fluoride (PVDF) membrane was developed for arsenate removal from simulated contaminated water. A PVDF flat-sheet membrane was first fabricated; it was then soaked in a zirconium-PVA solution and dried, and finally reacted with a glutaraldehyde solution, by which the zirconium ions were impregnated onto the PVDF surface through the ether and hydroxyl groups according to the cross-linkage mechanism. The fabrication procedure was optimized by the Box-Behnken experimental design approach. The adsorption kinetics study showed that most of uptake occurred in 5 h and the equilibrium was established in 24 h. The acidic condition was beneficial for the arsenate removal and the optimal removal efficiency can be obtained at pH 2.0. The experimental data of the adsorption isotherm was better described by Langmuir equation than Freundlich equation. The maximum adsorption capacity of 128 mg-As/g was achieved at pH 2.0. In the filtration study, the modified membrane with an area of 12.56 cm(2) could treat 15.6 L arsenate solution (equivalent to 75,150 bed volumes) with an influent concentration of 98.6 μg/L to meet the maximum contaminate level of 10 μg/L. Several instrumental studies revealed that the removal was mainly associated with ion exchange between chloride and arsenate ions.

[Aluminuminduced impairment in primary cultured rat choroid plexus epithelial cells]

OBJECTIVE

To investigate the impairment in primary cultured rat choroid plexus epithelial cells (CPECs)induced by aluminum.

METHODS

The choroid plexus isolated from Sprague-Dawley rats 14 days old was cut into pieces and digested by trypsin in the sterile area. The obtained single cells were cultured in DMEM with 1% epidermal growth factor and 20% fetal calf serum. Five days later, immunohistochemistry with anti-transthyretin antibody was used to identify the purity of cultured cells. The well-grown cells were treated with aluminum lactate at different concentrations (0, 100, 400, and 1 600 μmol/L for control, lowdose, mediumdose, and highdose groups). Fortyeight hours later, the cell viability, apoptotic rate, level of reactive oxygen species (ROS), and activity of superoxide dismutase (SOD)were measured in each group to evaluate the impairment in primary cultured rat CPECs by aluminum.

RESULTS

More than 95% of the cultured cells were identified as CPECs. The medium-and high-dose groups had significantly lower cell viability than the control group(86.74%±4.03% vs 100%, P<0.01; 81.90%±9.17% vs 100%, P<0.01). The high-dose group had significantly lower cell viability than the lowdose group (81.90%±9.17% vs 92.92%±8.81%, P<0.01). The medium-and high-dose groups had significantly higher apoptotic rates than the control group (7.26%±0.99% vs 1.29%±0.03%, P<0.01; 22.25%±1.55% vs 1.29%±0.03%, P<0.01)and the low-dose group (7.26%±0.99% vs 1.68%±0.27%, P<0.01; 22.25%±1.55% vs 1.68%±0.27%, P<0.01). The high-dose group had a significantly higher apoptotic rate than the medium-dose group (22.25%±1.55% vs 7.26%±0.99%, P<0.01). The mediumand high-dose groups had significantly higher fluorescence intensity of ROS than the control group (22.23%±0.41% vs 17.24%±0.09%, P<0.05; 25.10%±1.13% vs 17.24%±0.09%, P<0.05)and the lowdose group (22.23%±0.41% vs 18.31%±0.21%, P<0.05; 25.10%±1.13% vs 18.31%±0.21%, P<0.05). The highdose group had significantly higher fluorescence intensity of ROS than the mediumdose group (25.10%±1.13% vs 22.23%±0.41%, P< 0.05). The low-, medium-and high-dose groups had significantly lower SOD activity than the control group[(28.65±0.74)U/g Hb vs (37.35±1.05)U/g Hb, P<0.05; (22.75±1.94)U/g Hb vs (37.35±1.05)U/g Hb, P<0.05; (13.29±0.64)U/g Hb vs(37.35±1.05)U/g Hb, P<0.05]. The medium-and high-dose groups had significantly lower SOD activity than the low-dose group[(22.75±1.94)U/g Hb vs(28.65±0.74)U/g Hb, P<0.05; (13.29±0.64)U/g Hb vs (28.65±0.74)U/g Hb, P<0.05], while the high-dose group had had significantly lower SOD activity than the medium-dose group[(13.29±0.64)U/g Hb vs (22.75±1.94)U/g Hb, P<0.05]. There were no significant differences in cell viability, apoptotic rate, level of ROS, or activity of SOD between any other two groups (P>0.05).

CONCLUSION

Aluminum lactate may induce impairment in primary cultured rat CPECs. It reduces the cell viability, elevates the apoptotic rate, and causes oxidative stress.

[Effects of subchronic aluminum lactate exposure on learning and memory and transportation of Aβ in blood-cerebrospinal fluid in rats]

OBJECTIVE

To investigate the effects of aluminum lactate exposure on learning and memory and the transportation of amyloid-beta peptides(Aβ) in cerebrospinal fluid in rats.

METHODS

A total of 80 male Sprague-Dawley rats were randomly divided into solvent control(distilled water) group and low-, medium-, and high-dose aluminum poisoning groups(10, 30, and 90 mg/kg aluminum lactate), with 20 rats in each group, and the poisoning procedure was performed by gavage for 2 months. The Morris water maze test was used to test the rats' learning and memory, Western blot was used to measure the expression level of low-density lipoprotein receptor protein-1(LRP-1) in rats' choroid plexus, and enzyme-linked immunosorbent assay(ELISA) was used to measure the content of Aβ in the cerebrospinal fluid and plasma.

RESULTS

The Morris water maze test showed that in the place navigation test, with the increasing training time, the escape latency was significantly shortened in each group and showed significant differences between any two groups(P<0.05). In the spatial probe test, the time spent in target quadrant in the medium-and high-dose groups was 11.52±1.56 s and 10.43±5.27 s, respectively, which was significantly shorter than that in the control group and the low-dose group(15.81±3.01 s and 13.91±2.17 s)(P<0.05). The numbers of platform crossings in the medium-and high-dose groups were 2.64±1.39 and 1.50±0.76, respectively, which were significantly lower than those in the control group and the low-dose group(4.29±0.914 and 3.56±1.38)(P<0.05). The results of ELISA showed that the medium-and high-dose groups had significant increases in the content of Aβ1-42 in cerebrospinal fluid(320.35±84.82 pg/ml and 327.68±67.51 pg/ml), which was significantly higher than that in the control group(203.46±74.36 pg/ml) (P<0.05). The content of Aβ1-42 in plasma showed no significant difference between any two groups(P>0.05), and that of Aβ1-40 in cerebrospinal fluid and plasma also showed no significant difference between any two groups(P>0.05). The results of Western blot showed that the high-dose group had significantly lower protein expression of LRP-1 than the control group and the low-and medium-dose groups(0.57±0.21 vs 1.00±0.00/0.79±0.15/0.95±0.24, P<0.05).

CONCLUSION

Subchronic aluminum exposure may reduce learning and memory in rats, and the accumulation of Aβ in cerebrospinal fluid may be related to the reduced protein expression of LRP-1 in the choroid plexus, suggesting that aluminum affects learning and memory in rats through reducing the protein expression of LRP-1, influencing the transportation of Aβ, and leading to the accumulation of Aβ.

A metal–organic framework/α-alumina composite with a novel geometry for enhanced adsorptive separation

Incorporation of MOF UiO-66 into an advanced α-alumina matrix leads to a novel composite concept for enhanced adsorptive separation.

Applications of water stable metal–organic frameworks

A comprehensive review is given on the applications of water stable metal–organic frameworks in areas of adsorption, membrane separation, sensing, catalysis, and proton conduction.

Fabrication and testing of zirconium-based nanoparticle-doped activated carbon fiber for enhanced arsenic removal in water

A Zr-nanoparticle-doped ACF from this study shows a great potential for removal of arsenic from contaminated groundwater.

Measurement of the Target-Normal Single-Spin Asymmetry in Quasielastic Scattering from the Reaction (3)He(↑)(e,e')

We report the first measurement of the target single-spin asymmetry, A(y), in quasielastic scattering from the inclusive reaction (3)He(↑)(e,e') on a (3)He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A(y) can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q(2)=0.13, 0.46, and 0.97  GeV(2). These measurements demonstrate, for the first time, that the (3)He asymmetry is clearly nonzero and negative at the 4σ-9σ level. Using measured proton-to-(3)He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q(2) is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q(2)=0.97  GeV(2) agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions.

A review on polyamide thin film nanocomposite (TFN) membranes: History, applications, challenges and approaches

This review focuses on the development of polyamide (PA) thin film nanocomposite (TFN) membranes for various aqueous media-based separation processes such as nanofiltration, reverse osmosis and forward osmosis since the concept of TFN was introduced in year 2007. Although the total number of published TFN articles falls far short of the articles of the well-known thin film composite (TFC) membranes, its growth rate is significant, particularly since 2012. Generally, by incorporating an appropriate amount of nanofiller into a thin selective PA layer of a composite membrane, one could produce TFN membranes with enhanced separation characteristics as compared to the conventional TFC membrane. For certain cases, the resulting TFN membranes demonstrate not only excellent antifouling resistance and/or greater antibacterial effect, but also possibly overcome the trade-off effect between water permeability and solute selectivity. Furthermore, this review attempts to give the readers insights into the difficulties of incorporating inorganic nanomaterials into the organic PA layer whose thickness usually falls in a range of several-hundred nanometers. It is also intended to show new possible approaches to overcome these challenges in TFN membrane fabrication.

Rapid development of polymorphic microsatellite markers for the Amur sturgeon (Acipenser schrenckii) using next-generation sequencing technology

Anthropogenic activities have seriously impacted wild resources of the Amur sturgeon, Acipenser schrenckii, and more information on local and regional population genetic structure is required to aid the conservation of this species. In this study, we report the development of 12 novel polymorphic microsatellite loci using next-generation sequencing technology, and the genotyping of 24 individuals collected from a sturgeon farm. The results show that the mean number of ob-served alleles per locus is 6.6 (ranging from 2 to 17). Observed and expected heterozygosity values ranged from 0 to 0.958 and from 0.508 to 0.940, respectively. Not a single locus showed significant departure from Hardy-Weinberg equilibrium and no linkage disequilibrium was observed among any pairwise loci. These highly informative microsatellite markers will be useful for genetic diversity and population structure analyses of A. schrenckii and other species of this genus.