Dimethylacetamide Research Articles

Direct electrochemical extraction of metallic Li from a molecular liquid–Based electrolyte under ambient conditions

The high chemical activity of metallic Li hinders its efficient electrochemical extraction at low temperatures, necessitating the use of energy- and cost-intensive methods such as vacuum thermal reduction or electrodeposition from ionic-liquid and molten-salt electrolytes. Herein, we report the direct room-temperature electrowinning of metallic Li from a simple low-cost electrolyte, namely a solution of LiCl in dimethylacetamide (DMAc), determine the optimal concentration of LiCl, and examine the redox processes in the optimized system. Potentiostatic deposition on high-purity Al is shown to induce solid-state cathode alloying and thus produce a uniform, flat, and dense coating of a LiAl master alloy comprising spherical clusters formed by LiAl alloy nanosheets. Finally, the direct smelting of electrodeposited films is proposed as a method of rapidly realizing the “thin film” to “bulk” transformation of electrodeposited materials to stabilize metallic Li and form bulk Li-based alloys. Thus, this study provides a basis for the continuous, low-cost, sustainable, and fast electrochemical production of bulk active metals or their alloys.

Dimethylacetamide - an alternative to glycerol as cryoprotectant of Malabari buck semen

The key role of a cryoprotectant is to minimize the chemical and physical stress which occurs during cooling, freezing and thawing of semen. The difference between the cryoprotectant (CPA) occurs in their permeability coefficient and the structural model of the cryogenic agent. The beneficial effect of dimethylacetamide (DMA) as a cryoprotectant especially for sperms had been observed in several studies. The aim of the study was to study the cryoprotective effect of DMA in freezing the Malabari buck semen compared to glycerol. Ten ejaculates were taken from fourMalabaribucks . After preliminary evaluation sample split technique was followed with Tris based extender containing glycerol (6.7 per cent) as cryoprotectant (control) and Trisextender containing DMA (3 per cent) as cryoprotectant (treatment group). The semen straws (0.25mL) after filling were subjected for equilibration and manual freezing. Sperm kinetics was studied using computer-aided sperm analyzer. Pre-freeze and post-thaw evaluation included sperm viability, sperm abnormality, hypo osmotic test, acrosome integrity test and DNA fragmentation. Results indicated that inclusion of 6.7 per cent glycerol had significantly higher (p<0.05) post-thaw values than DMA. From our study we conclude that 6.7 per cent glycerol was better than 3 per cent DMA in cryopreservation of Malabari buck semen.

Dimethyl acetamide and dimethyl sulfoxide associated at glucose and egg yolk for cryopreservation of Pseudoplatystoma corruscans semen

Abstract This study aimed to develop a protocol for the cryopreservation of Pseudoplatystoma corruscans semen. For this, mature males were hormonally induced with a single dose of carp pituitary extract (5 mg/kg body weight). Semen was collected and evaluated. Two cryoprotectants were tested to compose the diluents: dimethyl acetamide (DMA) and dimethyl sulfoxide (Me2SO), in two concentrations (8% and 10%), + 5.0% glucose + 10% egg yolk. The semen was diluted in a 1: 4 ratio (semen: extender), packed in 0.5 mL straws and frozen in a dry shipper container in liquid nitrogen vapors. After thawing, sperm kinetics, sperm morphology and DNA integrity of cryopreserved sperm were evaluated. Pseudoplatystoma corruscans males produced semen with sperm motility > 80%. After thawing, all treatments provided semen with total sperm motility > 40%, with no significant difference (P < 0.05) between them, as well as between the other sperm kinetic parameters evaluated. The treatments with DMA provided a smaller fragmentation of the DNA of the gametes. Sperm malformations were identified in both fresh and cryopreserved semen, with a slight increase in these malformations being identified in sperm from thawed P. corruscans semen samples.

Volumetric, dielectric, and spectroscopic studies for the binary mixtures of glycerol and dimethylacetamide at T= (298.15–323.15) K

In this paper, density (ρ), volumetric (Vm), and thermal expansibilities (αP) of Glycerol (Gly) with Dimethylacetamide(DMA) binary mixtures are measured in the temperature range298.15 K-323.15 K. The dielectric permittivity of Gly + DMAbinary mixtures is also determined at different temperatures in the microwave frequency range 0.02 < ν/GHz < 20. The relaxation time (τ) of the binary mixtures is computed from the Havriliak-Negami relation. The excess parameters of volumetric (VmE), thermal expansibilities (αPE), refractive indices), relaxation time (1/τ) E, and molar polarization (PmE) are fitted with the Redlich-Kister polynomial equation. The negative values of VmE, αPE, nDE, and (1/τ) E parameters at all concentrations and temperatures suggest the presence of hydrogen bond interactions in the liquid system. The presence of H- bond between Gly & DMA is conformed from the FT-IR Spectra. The results were analysed in terms of molecular interactions among the components in the mixture mediated by hydrogen bonding.

One-step post-treatment boosts thermoelectric properties of PEDOT:PSS flexible thin films

• High power factor of 64.4 µW m −1 K −2 is achieved in PEDOT:PSS films at 360 K. • 80 vol.% DMAC solution boosts the electrical conductivity from 5 to 964 S cm −1 . • 0.5 mol L −1 LAA improves the Seebeck coefficient from 18.7 to 25 µV K −1 . • Mott variable range hopping model explains the thermoelectric transport behavior. Developing high-performance poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) significantly widens the practical applications of flexible organic thermoelectric devices, while the water-based co-solvent dopants and/or post-treatments are still rarely studied so far. Here, we develop a one-step post-treatment to improve the power factor of PEDOT:PSS films by using a water-based solution, which is composed of co-solvent (polar solvent dimethylacetamide (DMAC) and deionized water) and organic reducing agent L-ascorbic acid (LAA). The 80 vol.% DMAC solution significantly boosts the room-temperature electrical conductivity of the films from 5 to 964 S cm −1 , while the Seebeck coefficient can be further enhanced from 18.7 to 25 µV K −1 by treating with 0.5 mol L −1 LAA, contributing to a significantly improved power factor of 55.3 µW m −1 K −2 . The boosted electrical conductivity is ascribed to the separated PEDOT and PSS phases triggered by the high dielectric constant and polarity of DMAC; while the improved Seebeck coefficient is attributed to the reduced oxidation degree of PEDOT from the reducing agent LAA, both confirmed by the comprehensive structural and morphological characterizations. Furthermore, a maximum power factor of 64.4 µW m −1 K −2 can be achieved at 360 K and the observed temperature-dependent electrical transport behavior can be well explained by the Mott variable range hopping model. Besides, a flexible thermoelectric device, assembled by the as-fabricated PEDOT:PSS films, exhibits a maximum output power of ∼23 nW at a temperature difference of 25 K, indicating the potential for applying to low-grade wearable electronics.

PROTECTIVE ENVIRONMENTS FOR ANIMAL SPERM: EVOLUTION OF METHODS AND TOPICAL ASPECTS (REVIEW ARTICLE)

A retrospective review of domestic and foreign sources of literature is presented, as well as data of published own research on cryopreservation of animal sperm. The main historical stages of the creation of protective environments for deep freezing of sperm are given. In the 30s of the last century, a phenomenon characterized by the death of spermatozoa upon sharp cooling in the range of positive temperatures was discovered. It is called temperature shock of sperm. To prevent it, it is proposed to add substances containing phospholipids to the composition of diluents. Such environments can contain both simple components - native chicken egg yolk or milk, and high-tech - lipoproteins, isolated phospholipids of various origins. To stabilize protein-lipid complexes of plasma membranes and acrosomes of sperm during the cooling process, carbohydrates are added to the diluents. Sugars are components of energy supply for sperm and, along with salts, they are the main osmotic regulators. A combination of two or three carbohydrates in the medium was traditionally considered necessary. However, the Kharkiv school of reproductive specialists has proven the possibility of creating effective protective environments using only one sugar - sucrose or lactose - based on considerable practical experience. The effectiveness of germ cell freezing is shown depending on the cryoprotectants used. Glycerin is the first known endocellular cryoprotectant, which is still unsurpassed in sperm cryopreservation. Our own experimental data on the effect of combinations of glycerol with substances from the amide group on the main biological indicators of sperm after deconservation are presented. Cryoprotectants dimethylacetamide (DMAC) and dimethylformamide (DMF) were tested in own experiments on stallion semen. The experiments studied the effect of different concentrations of the above-mentioned penetrating cryoprotectants both on the main physiological characteristics of stallion sperm (motility, survival), and on the degree of damage to the membrane apparatus of sperm. The effectiveness of certain combinations of these substances has been proven. Methods of preventing the negative impact of oxygen and the development of lipid peroxidation processes in sperm during cryopreservation are presented. The concept of using additional hormonal components in diluents, in particular prostaglandin F2a, is revealed. The materials related to the effect on the quality of reproductive cells of healing preparations are displayed. Keywords: artificial insemination, environments, semen, animals, bulls, stallions, cryoprotectants, freezing.

Promotional effect of ammonium chloride functionalization on the performance of polyethersulfone/chitosan composite-based ultrafiltration membrane

This study aims to determine the effect of ammonium chloride (NH4Cl) on the characteristics and performance of polyethersulfone (PES)/Chitosan (CS)-based ultrafiltration composite membranes. The PES membranes were synthesized using phase inversion technique in dimethylacetamide (DMAc) solvent. A mixture of chitosan solution (fixed concentration) and NH4Cl (concentration 100–400 ppm) with ratio 2:1 (v/v) were coated into the PES membrane. The synthesized membranes morphology and properties were characterized by FTIR, SEM, contact angle, mechanical properties, and porosity tests. The membrane performance parameters including water permeability, rejection, and antifouling properties were studied. Incorporation of NH4Cl modified the membrane morphology and improved membrane porosity (49.64–71.5 %). The decrease in the water contact angle (80.21° to 63.53°) has confirmed the improvement of membrane hydrophilicity. Moreover, improved mechanical properties (11–16 MPa) were observed due to NH4Cl addition. The incorporation of NH4Cl improved water flux and specific flux membranes in dead-end cell from 51.34 to 159.18 L/m2∙h and 22–26.53 L/m2∙h∙bar, respectively, and in the cross-flow cell from 82.38 to 182.53 L/m2∙h and from 16.47 to 36.51 L/m2∙h∙bar, respectively. The addition of NH4Cl into membrane remarkably improved the rejection of bovine serum albumine (75.90 %, to 96.79 %), methyl orange (47.18–89.29 %), and methylene blue (60.14–97.34 %) Composite membranes have good fouling resistance as indicated by an increase in the flux recovery ratio (53.58–70.67 %). It is inferred that the addition of NH4Cl improved the performance of PES/chitosan composite membranes in ultrafiltration.

1,2,4-Triazole (Htrz) functionalised 2D-manganese-organic framework (UPMOF-5) as a battery-type electrode for supercapattery

Metal-organic frameworks (MOFs) have attracted a lot of attention in the field of energy storage and conversion due to their unique properties, including large specific surface areas, adjustable pore sizes and stable porous structures. Herein, we report a novel porous Mn-based MOF that was prepared through a facile solvothermal method using 1,2,4-triazole (Htrz) organic linker in the presence of N, N’-dimethylacetamide (DMA) as a solvent. The novel [Mn(Htrz)(DMA)Br] denoted as UPMOF-5 crystallised in a monoclinic P21 space group showing a two-dimensional (2D) structure and a large BET surface area of 1725 m2/g. For the first time, the synthesised manganese-1,2,4-triazolate framework (UPMOF-5) was used as an electrode in supercapattery device assembly. Impressively, a battery-graded nature was shown in the three-electrode assembly of the UPMOF-5, which had a decent specific capacity of 160.17 C/g at 0.4 A/g. The designed supercapattery device with UPMOF-5 as a positive electrode and activated carbon as a negative electrode delivered a good specific capacity of 132.40 C/g at 0.4 A/g with 24.77 Wh/kg of specific energy at 538.91 W/kg of specific power. After 10,000 cycles, the device showed promising capacity retention of 70.3 %. The structural stability and porous character of UPMOF-5 are credited with the decent electrochemical performance.

A novel and effective approach to enhance the interfacial interactions of meta-aramid fibers

Meta-aramid paper exhibits some unique properties, including high temperature resistance, electrical insulation. However, due to the inherent chemical inertness of aramid fibers, the interfacial bonding between fibers is weak, which negatively affect the properties of aramid paper. Herein, we report a simple, effective and scalable process for substantially improving the interfacial bonding between aramid fibers, thus, mechanical and insulating properties of the meta-aramid composite paper, and it was achieved by surface coating of aramid paper with meta-aramid stock solution that contains N, N dimethylacetamide (DMAc)-CaCl2 and high molecular weight poly (m-phenylene isophthalamide) polymers. Results show that the tensile strength, modulus, internal bond strength and tearing index of the resultant all-PMIA paper increased by 83 %, 58 %, 173 % and 89 %, respectively, in comparison with those of the control. The breakdown strength of the improved aramid paper is 190 % higher than that of the control paper, attaining 26.46 KV/mm. This work provides a simple, economical, efficient, and scalable method to improve the overall performance of meta-aramid paper, which has great potential to be implemented at the industrial scale.

Solvent induced effect on morphology and properties of disulfonated polyarylene ether sulfone block copolymer membranes for PEMFC applications

A systematic investigation to ascertain a fundamental understanding of the residual solvent effect on the bonding characteristics, thermal and mechanical properties of poly(arylene ether sulfone) (PAES) membranes was carried out. Transparent PAES membranes were synthesized using different solvents, which include dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), and N-methyl-2pyrrolidone (NMP). A correlation was established between polymer-solvent interaction using Hansen solubility parameters (HSP) and Flory-Huggins interaction parameters (χP-S). Proton conductivity, thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and FTIR were correlated with χP-S parameter. PAES membrane derived using DMF solvent exhibited the highest proton conductivity (0.133 ± 0.01 S∙cm−1). Scanning electron microscopy (SEM) confirmed the formation of defect-free membranes. The presence of residual solvent in the membranes resulted in a plasticizer effect which was confirmed through storage modulus behavior from DMA. This study will act as a standard protocol for the development of high-performance PAES membranes with desired properties for polymer fuel cells applications.

Solvent-controlled synthesis of Ti-based porphyrinic metal-organic frameworks for the selective photocatalytic oxidation of amines.

The photocatalytic activity of metal-organic frameworks (MOFs) can be managed by the milieu of synthesis. Herein, N,N'-dimethylacetamide (DMA) and N,N'-diethylformamide (DEF) were employed as solvents for the synthesis of two Ti-based porphyrinic MOFs, namely Ti-PMOF-DMA and Ti-PMOF-DEF, from tetrabutyl orthotitanate and 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid). Notably, both DMA and DEF were adsorbed onto the Ti-oxo clusters of the two MOFs to shape their properties. Ti-PMOF-DMA was observed with better optoelectronic response and charge transfer than Ti-PMOF-DEF. Moreover, Ti-PMOF-DMA owned a larger pore volume than Ti-PMOF-DEF, imparting more accessible sites to benzyl amines. Ti-PMOF-DMA exhibited better activity in selective photocatalytic aerobic oxidation of benzylamine than Ti-PMOF-DEF. Irradiated by red light-emitting diodes, outstanding results for selective conversion of benzyl amines to imines over Ti-PMOF-DMA were attained. Superoxide radical anion, generated by the electron transfer from porphyrin via Ti-oxo clusters to dioxygen, turned out to be the primary reactive oxygen species. There was generality towards aerobic oxidation of amines to imines and considerable stability for Ti-PMOF-DMA. This work provides a new perspective on the altering MOFs to enhance photocatalytic organic transformations.

Improved Subcutaneous Delivery of Ketoconazole Using EpiDerm and HSPiP Software-Based Simulations as Assessed by Cell Viability, Cellular Uptake, Permeation, and Hemolysis In Vitro Studies.

Ketoconazole (KETO) is the drug of choice to control local, systemic, and resistant types of fungal infections. Subcutaneous (sub-Q) delivery offers several benefits. The present study investigated the sub-Q delivery of KETO using HSPiP software based on optimized concentrations of dimethylacetamide (DMA) in binary solvents (DMA + water), in vitro cellular uptake (J774A.1) assays, cellular toxicity (L929), and in vitro hemolysis studies. Results showed that the estimated permeation coefficient (9.6 × 10-3 cm/h) and diffusion coefficient (3.9 × 10-3 cm2/h) of KETO (22.3 mg) in KF3 (300 mg of DMA + water) across EpiDerm were relatively higher as compared to the other formulations [KF1 (11.2 and 150 mg as KETO and DMA, respectively) and KF2 [(22.3 and 300 mg as KETO and DMA, respectively)] due to the increased content of DMA and KETO. HSPiP simulated and predicted the impact of constant and variable diffusion coefficients on the percent drug absorption across EpiDerm and the time needed to achieve equilibrium. The concentration-dependent diffusion coefficient fed into HSPiP predicted that the drug absorption and permeation values were linearly dependent on the square root of time. The HSPiP predicted permeation flux values from KF3, KF2, and KF1 across the EpiDerm were 4.07 × 10-6, 4.01 × 10-6, and 1.1 × 10-6 g/cm2/s, respectively, at respective D range values. The selected K30G (324 mOsm/Kg) showed an optimal pH (6.9) and minimum drug loss (0.01%) over a period of 1 month at room temperature. KG30 was found to be less toxic to normal L292 cells and caused maximum cytotoxicity to candida cells residing within infected macrophage cells (J774A.1 incubated for 24 h), which was attributed to the slow diffusion of K30G compared to DS (the drug solution with an equivalent concentration). KG30 elicited substantial internalization with candida albicans (MTCC 4748) compared to the control group (24 h). Lastly, in vitro hemolysis studies (1 and 5 μg/mL) corroborated the safety of K30G for sub-Q delivery. Therefore, this new formulation and approach for delivering KETO is a promising alternative to conventional products to control fungal infections and, thus, should be further studied in vivo.

Recovery of carbon fiber-reinforced polymer waste using dimethylacetamide base on the resin swelling principle.

The mechanical recycling method of the carbon fiber-reinforced polymer (CFRP) has the advantages of simple process, less pollution and low cost, but only low utilization value of carbon fibers in powder or short fibers form can be obtained. To reduce the length and strength loss of the recycled carbon fibers, a novel and cost-effective dimethylacetamide (DMAC) swelling technique was developed to achieve rapid delamination of the CFRP laminates under mild conditions (120°C-160°C, 1h). The corresponding swelling ratios and mass-loss rates of cured epoxy resin (CEP) were about 121.39%-157.39% and 0-0.69%, respectively. Excessive swelling of CEP in DMAC resulted in the cracking of the resin matrix between the adjacent carbon fiber layers. Thus the CFRP laminates were delaminated into soft single carbon fiber layers, which showed excellent cutting performance and reinforcing properties. The delamination products were cut into thin strips of different sizes and vacuum bag molded into new CFRP laminates. The flexural strength and tensile strength of the newly produced CFRP laminates were about 76.38%-90.98% and 94.61%-98.54% of the original CFRP laminates, respectively. More importantly, the chemical compositions of DMAC and CEP were unchanged during the physical swelling process. No organic pollutants (caused by resin degradation) were generated. And the used DMAC can be easily recycled by filtration. Therefore, this study provides a strategy for low-cost and high-valued recycling of CFRP waste.

The Use of Pectins As Part of a Cryoprotective Solution For Long-term Storage of Human Platelet Concentrates

BACKGROUND: Pectins have unique properties and great potential to become an indispensable component of cryoprotective environment for platelet freezing. OBJECTIVE: To investigate the possibility of including pectins (apple pectin AU-701, tanacetan) into the composition of a cryoprotective solution for platelets during low-temperature storage. MATERIALS AND METHODS: Samples of platelet concentrates (PC) were frozen under the protection of complex solutions and stored in an electric freezer at -80 °C for 1 and 6 months. RESULT: The study showed that of the basic cryoprotectants, the best effect in the preservation of PC was with dimethylacetamide (DMAC). The use of pectins as an additive to the base solution of DMAC statistically improves the preservation of PC after exposure to low temperatures (-80 ° C) for 30 and 180 days. CONCLUSIONS: We conclude that DMAC is more promising as a basis for the development of a new combined cryoprotectant for PC freezing. Moreover, the chemical structure of pectin determines the level of its cryoprotective action in relation to the preservation of PC.

Characterization Effect of Polysulfone Membranes with Different Molecular Weight of Polyethylene Glycol Additives

Nowadays, membrane technology has gaining popularity in biotechnology, food processing, water treatment, pharmaceutical and semiconductor industries. It been reported as a potential technique for separation due to their low-cost process, does not used many chemical and energy sufficient. However, there is less study about polysulfone (PSF) used as a polymer based in membrane filtration with polyethylene glycol (PEG) as additives in different molecular weight (Mw: 400, 600, 1500, and 4000 Da). Therefore, this study has been conducted to investigate the effect of different molecular weight of PEG in terms of thermal stability, hydrophilicity, and porosity. For methodology, PSF polymer was fabricated with PEG and Dimethylacetamide (DMAc) act as solvent via wet phase inversion method. The physical, thermal and chemical characterization were analysed using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and laboratory testing of contact angle, water uptake, and porosity. The result showed improvement in fabricated membranes hydrophilicity than pure membrane. PEG with high molecular weight demonstrated the higher membrane hydrophilicity, good thermal stability (38.40%), contact angle (54°), higher water uptake (385.23%), and higher porosity (82.72%). As conclusion, PSF with addition of the high molecular weight of PEG (PEG4000) can improve the performance of membrane filtration.

Conductivity Study on Proton-Conducting Nanocomposite Plasticized Polymer Electrolytes: A Review

Abstract:This paper reviews proton-conducting polymer electrolytes comprising different polymers, salts, and acids. The ionic conductivity of plasticized polymer electrolytes has been found to increase with the addition of plasticizers due to the dissociation of ion aggregates or undissociated salt/acid present in the electrolytes, i.e., σ (plasticized polymer electrolytes) &gt; σ (unplasticized polymer electrolytes). Proton-conducting nonaqueous nanocomposite plasticized polymer electrolytes containing poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), polymethylmethacrylate (PMMA), polyethylene oxide (PEO) polymers; different ammonium salts and acids as proton conductors; ethylene carbonate (EC), propylene carbonate (PC), dimethylformamide (DMF), dimethylacetamide (DMA), dimethyl carbonate (DMC), diethyl carbonate (DEC) as plasticizers; fumed silica and alumina as nano-fillers have been discussed in details. Conductivity studies (effect of salt/acid, effect of plasticizers, effect of nano-fillers, and effect of temperature), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA) studies for these electrolytes have been discussed and reported in the paper. Nanocomposite plasticized polymer electrolytes showed high ionic conductivity (in the order of 10-1 to 10-2 S/cm) at room temperature along with good thermal and mechanical stability due to the simultaneous addition of both plasticizers and nano-fillers. These nanocomposite polymer electrolytes are the best candidates for use in various electrochemical devices like solid-state batteries, fuel cells, supercapacitors, sensors, separators, and other electrochromic devices.

Eco-friendly forward osmosis membrane manufacturing using dihydrolevoglucosenone

Semipermeable membranes are generally synthesized using solvents which harm the environment and human health. Common organic solvents like n-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMA), and dimethyl sulfoxide (DMSO) have been proven to cause damages to the environment and the human body. Therefore, finding environmentally friendly or green solvents to create what so called a green membrane has been a great interest. The green solvent should have little to no potential hazard and derived from renewable sources to make the membranes sustainable. Dihydrolevoglucosenone (Cyrene™) is an alternative green solvent derived from cellulose and eco-friendly as it does not release harmful emissions to the environment. In this study, CTA and CA as polymer were fabricated by using Cyrene™ as solvent to create green membranes via phase inversion methods. Six different polymer concentration variations were used along with Cyrene™, to produces forward osmosis (FO) membranes. The membranes were produced as an asymmetric structure with a dense skin layer and subporous middle layer with various pore sizes and thicknesses. Hydrophilic properties can be found in almost every Cyrene™-fabricated membrane. The membranes were then tested by using 1 M NaCl solution as the draw solution (DS) and deionized water as the feed solution (FS). The reasonably good flux, ranging from 1464.21 LMH to 1627.12 LMH were achieved. However, the membrane reverse solute flux (RSF) surpassed the usual range of RSF, ranging from 164.79 gMH to 870.44 gMH.

Effect of Dimethylacetamide Concentration on Motility, Quality, Antioxidant Biomarkers, Anti-Freeze Gene Expression, and Fertilizing Ability of Frozen/Thawed Rooster Sperm.

Simple SummaryAlthough sperm cryopreservation has a great potential for application in the poultry industry, it is still very limited at the economical scale due to the low fertility of frozen/thawed avian spermatozoa. Dimethylacetamide (DMA) has been widely employed as a cryoprotectant for the cryopreservation of chicken spermatozoa, but with variable results in motility and fertility. To determine the appropriate concentration of DMA in the chicken semen freezing extender, in vitro sperm quality and motility analyses and in vivo field trials based on the fertility of the frozen/thawed rooster sperm were conducted in the present study. The antioxidant biomarkers and novel anti-freeze-associated genes were also analyzed in the post-thawed sperm. Results conclude that DMA is preferably used at a low concentration to obtain applicable results in sperm motility and fertility after thawing without harming the quality and antioxidant system defense. The current study could highlight the possible molecular mechanisms behind the obtained fertility results of DMA-frozen sperm, especially when artificial insemination is implemented in the poultry industry.Sperm cryopreservation is of great importance for the poultry industry but still needs to be optimized. The high susceptibility of poultry sperm to cryodamage leads to low fertility rates after cryopreservation. Therefore, the present study aimed at evaluating the effect of including a cryoprotectant, dimethylacetamide (DMA), in the chicken semen freezing extenders at a final concentration of 3%, 6%, or 9% on the post-thawed sperm motility, quality, antioxidant biomarkers, anti-freeze gene expression, and fertilizing ability. Results showed that the total motile sperm, progressivity, and viability were quadratically increased (p < 0.05) in the 6% DMA group. The antioxidant enzyme activity and lipid peroxidation were negatively (p < 0.05) affected by the increase in DMA concentration. Furthermore, some anti-freeze-associated genes such as heat shock protein 70 (HSP70) and ras homolog family member A (RHOA) were linearly and quadratically down-regulated (p < 0.05) with the high concentration of DMA. Finally, the fertility and hatchability rates did not indicate statistical differences between DMA groups. It can be concluded that using the low concentration of 3–6% DMA in the freezing semen extender is preferable to obtain acceptable results in the post-thawed sperm quality and fertility.

Polybenzimidazole (PBI) membranes cross-linked with various cross-linkers and impregnated with 4-sulfocalix [4]arene (SCA4) for organic solvent nanofiltration (OSN)

The chemical, pharmaceutical, and edible oil industries have employed enormous amounts of organic solvents to produce medicines, chemicals, and other goods. In order to recycle these valuable organic solvents, organic solvent nanofiltration (OSN) is crucial. However, choosing the optimal cross-linker is vital for producing membranes with improved performance and chemical resistance. In this study, integrally skinned polybenzimidazole (PBI) flat membranes for OSN were studied through a covalent modification employing α, α′-dibromo-p-xylene (DBX), α, α′-dichloro-p-xylene (DCX) or trimesoyl chloride (TMC), followed by ionic impregnation with 4-sulfocalix [4]arene (SCA4). The nucleophilic-electrophilic reactions between PBI and cross-linkers and the ionic interactions among SCA4, PBI and cross-linkers were investigated and elucidated. Due to the two-fold modifications, the resultant PBI membranes show enhanced molecular sieving capabilities and chemical stability. Especially, the membranes modified with DBX and DCX, and then SCA4 infiltration demonstrate a wide range of stability in harsh organic solvents such as n-methyl-2-pyrrolidone (NMP) and dimethyl acetamide (DMAc). They also possess impressive rejections against low molecular weight (Mw) dyes, reconfirming their superiority in terms of structural and chemical stability to PBI for practical OSN uses. However, the dye rejection is still influenced by the physical characteristics of the solvents and dyes as well as the interactions among the solute, solvent, and membrane. This work may provide a workable plan to design membranes with precise molecular sieving capabilities for OSN.

Intrinsically Negative Photosensitive Polyimides with Enhanced High-Temperature Dimensional Stability and Optical Transparency for Advanced Optical Applications via Simultaneous Incorporation of Trifluoromethyl and Benzanilide Units: Preparation and Properties

Negative photosensitive polyimides (PSPIs) with the photo-patterned ability via the photocrosslinking reactions induced by the i-line (365 nm) and h-line (426 nm) emitting wavelengths in high-pressure mercury lamps have been paid increasing attention in semiconductor fabrication, optical fiber communications, and other advanced optoelectronic areas. In the current work, in view of the optical and thermo-mechanical disadvantages of the currently used negative PSPIs, such as the intrinsically photosensitive or auto-photosensitive systems derived from 3,3’,4,4’-benzophenonetetracarboxylic dianhydride (BTDA) and the ortho-alkyl- substituted aromatic diamines, a series of modified negative PSPIs with the enhanced optical transparency in the wavelength of 365~436 nm and apparently reduced coefficients of linear thermal expansion (CTE) were developed. For this purpose, a specific aromatic diamine with both of trifluoromethyl and benzanilide units in the molecular structures, 2,2’-bis(trifluoromethyl)-4,4’-bis[4-(4-amino-3-methyl)benzamide]biphenyl (MABTFMB) was copolymerized with BTDA and the standard 3,3’,5,5’-tetramethyl-4,4’-diaminodiphenylmethane (TMMDA) diamine via a two-step chemical imidization procedure. As compared with the pristine PI-1 (BTDA-TMMDA) system, the new-developed fluoro-containing PSPI systems (FPI-2~FPI-7) exhibited the same-level solubility in polar aprotic solvents, including N-methyl-2-pyrrolidone (NMP) and N,N- dimethylacetamide (DMAc). The FPI films cast from the corresponding FPI solutions in NMP showed the optical transmittances of 78.3–81.3% at the wavelength of 436 nm (T436, h-line), which were much higher than that of the PI-1 (T436 = 60.9%). The FPI films showed the CTE values in the range of 40.7 × 10−6/K to 54.0 × 10−6/K in the temperature range of 50 to 250 °C, which were obviously lower than that of PI-1 (CTE = 56.5 × 10−6/K). At last, the photosensitivity of the FPI systems was maintained and the micro-pattern with the line width of 10 μm could be clearly obtained via the standard photolithography process of FPI-7 with the molar ratio of 50% for MABTFMB in the diamine moiety.