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In this paper, we present research results that extend and supplement our article recently published by MDPI. We derive the closed-form relations among the queue-length probabilities observed in the pre-arrival, random, and post-departure epochs for a complex, bulk-service, multi-server queueing system GI/M a , b /c. [ABSTRACT FROM AUTHOR]

The African swine fever virus (ASFV) has the ability to infect pigs and cause a highly contagious acute fever that can result in a mortality rate as high as 100%. Due to the viral epidemic, the pig industry worldwide has suffered significant financial setbacks. The absence of a proven vaccine for ASFV necessitates the development of a sensitive and reliable serological diagnostic method, enabling laboratories to effectively and expeditiously detect ASFV infection. In this study, four strains of monoclonal antibodies (mAbs) against p72, namely, 5A1, 4C4, 8A9, and 5E10, were generated through recombinant expression of p72, the main capsid protein of ASFV, and immunized mice with it. Epitope localization was performed by truncated overlapping polypeptides. The results indicate that 5A1 and 4C4 recognized the amino acid 20–39 aa, 8A9 and 5E10 are recognized at 263–282 aa, which is consistent with the reported 265–280 aa epitopes. Conserved analysis revealed 20–39 aa is a high conservation of the epitopes in the ASFV genotypes. Moreover, a blocking ELISA assay for detection ASFV antibody based on 4C4 monoclonal antibody was developed and assessed. The receiver-operating characteristic (ROC) was performed to identify the best threshold value using 87 negative and 67 positive samples. The established test exhibited an area under the curve (AUC) of 0.9997, with a 95% confidence interval ranging from 99.87 to 100%. Furthermore, the test achieved a diagnostic sensitivity of 100% (with a 95% confidence interval of 95.72 to 100%) and a specificity of 98.51% (with a 95% confidence interval of 92.02 to 99.92%) when the threshold was set at 41.97%. The inter- and intra-batch coefficient of variation were below 10%, demonstrating the exceptional repeatability of the method. This method can detect the positive standard serum at a dilution as high as 1:512. Subsequently, an exceptional blocking ELISA assay was established with high diagnostic sensitivity and specificity, providing a novel tool for detecting ASFV antibodies. Key points: • Four strains of ASFV monoclonal antibodies against p72 were prepared and their epitopes were identified. • Blocking ELISA method was established based on monoclonal antibody 4C4 with an identified conservative epitope. • The established blocking ELISA method has a good effect on the detection of ASFV antibody. [ABSTRACT FROM AUTHOR]

Gossypol is a yellow polyphenol naturally produced by Malvaceae plants such as cotton, which mainly exists in roots, stems, leaves, and seeds of cotton. Gossypol has animal toxicity, and long-term intake of gossypol will accumulate in livestock and cause poisoning, resulting in decreased fecundity, organ lesions, and even death of animals. The cotton output in Xinjiang is huge, accounting for more than 80% of the whole country. After cotton harvest, most of the waste cotton straws are directly crushed and returned to the field, resulting in great waste of resources. Cotton straw is rich in crude protein, cellulose, hemicellulose, and lignin, which is equivalent to common crop straw in nutritional components. However, its gossypol content exceeded the standard, which limited the application of cotton straw feed. How to achieve efficient and low-cost detoxification of gossypol has become the key factor to determining the fodder of cotton straw. The structure, properties, toxicity, detoxification technology, and detoxification mechanism of gossypol were summarized in this paper, which provided a reference for feed utilization of cotton straw. [ABSTRACT FROM AUTHOR]

Membrane fouling induces catastrophic loss of separation performance and seriously restricts the applications of reverse osmosis (RO) membranes. Inspired by the mussel structure, polydopamine (PDA) and cystamine molecules (CA) with excellent anti-fouling properties were used to prepare accessible, biocompatible, and redox-responsive coatings for RO membranes. The PDA/CA-coated RO membranes exhibit a superior water flux of 65 L m−2 h−1 with a favourable NaCl rejection exceeding 99%. The water permeability through the PDA/CA-coated membrane is much higher than that of most membranes with similar rejection rates. Due to the formed protective hydration layers by PDA/CA coatings, anti-fouling properties against proteins, polysaccharides and surfactants were evaluated separately, and ultralow fouling properties were demonstrated. Moreover, the disulfide linkages in CA molecules can cleave in a reducing environment, yielding the degradation of PDA/CA coatings, thereby removing the foulants deposited on the coatings. The degradation endows the coated membranes with satisfying longtime anti-fouling properties, where the flux recovery reaches up to 90%. The construction of redox-responsive smart coatings not only provided a promising route to alleviate membrane fouling but can also be upscaled for use in numerous practical applications like sensors, medical devices, and drug delivery. [ABSTRACT FROM AUTHOR]

Context: Granulosa cells (GCs) that surround oocytes in mammalian reproduction play an active role in oocyte differentiation through proliferation and energy production. Aims: This study aimed to investigate the characteristics of the energy metabolism of ovarian GCs and the influence of GCs on the early embryonic development in polycystic ovary syndrome (PCOS). Methods: The clinical characteristics and in vitro fertilization-embryo transfer treatment outcomes of 39 patients with PCOS and 68 patients with simple tubal factor infertility who underwent controlled ovarian hyperstimulation were analyzed and summarized. The mitochondrial function and glucose metabolism level of the GCs were determined, as well as the content of oxidative stress markers in the follicular fluid (FF) of patients with and without PCOS. Key results: When compared to the non-PCOS group, patients with PCOS had a significantly increased number of retrieved oocytes but a significantly decreased number of high-quality embryos, available embryos, and high-quality blastocyst formation (P < 0.05). Furthermore, the mitochondrial membrane potential, adenosine triphosphate level, and mitochondrial DNA (mtDNA) copy number decreased in the GCs, whereas the levels of reactive oxygen species increased (P < 0.01). The levels of malondialdehyde and 8-oxo-deoxyguanosine (8-OHdG) in the follicular fluid (FF) of the patients with PCOS were higher than those of the control group (P < 0.05), and superoxide dismutase was increased by compensation (P < 0.05). In the PCOS group, the expressions of GLUT1, LDHA, and PFKP were lower than those in the non-PCOS group, and glucose levels were higher. Conclusions: The low oocyte competence of PCOS may be associated with mitochondrial dysfunction and abnormal glycolysis. Implications: This research offers explanations for the possible connections influencing human ovarian folliculogenesis. [ABSTRACT FROM AUTHOR]

Objective: To investigate the long‐term outcomes for Mayer–Rokitansky–Küster–Hauser syndrome (MRKH) patients undergoing vaginoplasty using acellular porcine small intestinal submucosa grafts (SIS). Design: A case series. Population: Seventy‐eight MRKH syndrome patients and a post‐SIS patient who delivered a baby following the world's first robot‐assisted uterus transplantation. Methods: Mayer–Rokitansky–Küster–Hauser syndrome patients were grouped based on the postoperative time and the diagnosis–surgery interval. Outcomes of sexual function and psychological status were assessed using the female sexual function index (FSFI), self‐rating scale of body image (SSBI) and self‐acceptance questionnaire (SAQ). Anatomical outcomes were measured by clinicians. Main Outcome Measures: The primary outcome was restoration of sexual function, defined by an FSFI score in the 'good' range. Anatomical and psychological outcomes were also analysed. Results: Sexual function was restored in 42.3% (33/78) of patients and the total FSFI score was 23.44 ± 4.43. Three factors (body defect, recognition of physical appearance and willingness to change physical appearance scores) in the SSBI and two in the SAQ decreased as the postoperative time increased. Based on the interval between diagnosis and surgery, the total SSBI score was lower in the short‐interval group than in the long‐interval group (7.25 ± 5.55 versus 12.04 ± 10.21, p = 0.038). Conclusions: Nearly half of MRKH patients in our study had good long‐term sexual function after SIS vaginoplasty. Sexual function and psychological status improved as postoperative time increased. In addition, reducing the diagnosis to surgery interval was associated with improved psychological function. [ABSTRACT FROM AUTHOR]

Bulk-service queueing systems have been widely applied in many areas in real life. While single-server queueing systems work in some cases, multi-servers can efficiently handle most complex applications. Bulk-service, multi-server queueing systems (compared to well-developed single-server queueing systems) are more complex and harder to deal with, especially when the inter-arrival time distributions are arbitrary. This paper deals with analytic and computational analyses of queue-length distributions for a complex bulk-service, multi-server queueing system GI/M a , b /c, wherein inter-arrival times follow an arbitrary distribution, a is the quorum, and b is the capacity of each server; service times follow exponential distributions. The introduction of quorum a further increases the complexity of the model. In view of this, a two-dimensional Markov chain has to be involved. Currently, it appears that this system has not been addressed so far. An elegant analytic closed-form solution and an efficient algorithm to obtain the queue-length distributions at three different epochs, i.e., pre-arrival epoch (p.a.e.), random epoch (r.e.), and post-departure epoch (p.d.e.) are presented, when the servers are in busy and idle states, respectively. [ABSTRACT FROM AUTHOR]

The common neglect of the prominent bacterial growth and accumulation on polymer‐based thermal conductive materials used in medical electronic devices will hurt the functionality and lifetime of medical devices, and sometimes even lead to medical accidents. In this study, we developed a novel ternary composite with excellent antimicrobial and thermal conductive properties to solve this problem. This composite was composed of antimicrobial functionalized hexagonal boron nitride (AB@h‐BN) nanoplatelets, low melt alloys (LMAs), and epoxy. Antimicrobial testing showed that the AB@h‐BN/LMAs/epoxy composites were 100% against both Escherichia coli and Staphylococcus aureus; their antibacterial mechanism was contact killing and was harmless to the environment. Besides enhancing the antimicrobial property, the AB@h‐BN nanoplatelets connected the mutually independent LMAs, forming the continuous network for heat conduction in the epoxy. Benefited from this distinctive structure, the thermal conductivity of AB@h‐BN/LMAs/epoxy can reach 2.66 Wm−1 k−1, which represented an enhancement of about 1141% over the pure epoxy. [ABSTRACT FROM AUTHOR]

Bilayer nanofiltration (NF) membranes tend to delaminate and have poor stability when applied in organic solvents due to their bi-layered structure. In this study we prepared two types of polydopamine (PDOPA) modified NF membranes including PDOPA-TMC (trimesoyl chloride)/PSF and PDOPA/PIP(Piperazine)-TMC/PSF NF membranes on polysulfone (PSF) ultrafiltration membranes via interfacial polymerization based on PDOPA's specialized molecular structure and high adhesion property. The separation performance and stability of the NF membranes were investigated. Both the polyester bonds of the PDOPA bilayer membranes and the bioadhesion of the PDOPA were simultaneously beneficial to improving the structure and chemical stabilities of the bilayer membranes. After soaking both the PDOPA-TMC/PSF and PDOPA/PIP-TMC/PSF NF membranes in ethanol solvent for 12 days, the rejection of Congo red only decreased by 1.8% (original, 99.9%) and 1.2% (original, 99.9%), respectively. For the PDOPA/PIP-TMC/PSF NF membrane, the rejection of Na2SO4 was only reduced by 1.6% (original, 98.5%). Moreover, the separation performances of both the PDOPA-TMC/PSF and PDOPA/PIP-TMC/PSF NF membranes were still excellent after soaking in a sodium hypochlorite solution (50 ppm) for 240 h (12,000 ppm·hours). The NF membranes thus exhibited long-term structural stability in ethanol and excellent chemical stability in the sodium hypochlorite solution. In particular, no delamination was observed in the above experiments, which is significant for their use in the wastewater treatment field. [ABSTRACT FROM AUTHOR]

Biofouling, as one of the membrane foulings, is the major obstacle limiting the application of polyamide (PA) thin-film composite (TFC) nanofiltration (NF) membranes in reclamation of wastewaters and treatment of industrial fluids. Herein, we introduced a facile and effective strategy for the modification of traditional PA-TFC NF membranes to improve water permeability and biofouling resistance. Specifically, three reactive guanidine molecules were successfully bonded onto the surface of PA-TFC membranes using chemical reactions between the amine groups of guanidine and the residual acyl chloride groups on the nascent PA-TFC membrane. The covalent attachment of guanidines can significantly enhance water permeability without compromising salt rejection. For instance, for 2 g L−1 Na2SO4 aqueous solution, the water flux of NFM2 increased from 25.2 L m−2 h−1 to 68.4 L m−2 h−1 at 25 °C and 0.6 MPa compared to the traditional piperazine (PIP)–trimesoyl chloride (TMC) membrane, while around 98.3%. Na2SO4 rejection was maintained. Moreover, the membranes were endowed with easy-cleaning properties, which can remarkably prevent foulant adhesion, with the water flux recovery ratio being as high as 98.9%. The developed TFC membranes also showed excellent anti-adhesive and antimicrobial activities against Gram-negative Escherichia coli K12 (E. coli), Gram-positive Bacillus pumilus LDS33 (B. pumilus) and Aspergillus parasiticus JFS (A. parasiticus). Therefore, the resultant guanidinium-functionalized NF membranes which have integrated high permselectivity and superior fouling resistance properties are promising materials for fabricating a new generation of anti-fouling/antimicrobial surfaces that are applicable to many applications such as water desalination and softening and wastewater treatment. [ABSTRACT FROM AUTHOR]

ABSTRACT For the applications of reverse osmosis (RO) process, membrane fouling caused by organic molecule adsorption is still a serious problem which significantly decreases membrane lifespan and increases operation costs. In this present article, we report the thin film composite (TFC) RO membrane functionalized with tris(hydroxymethyl)aminomethane (THAM) using one-step method for improved antifouling property. The results of surface characterization indicated that THAM was successfully grafted onto the active layer of membrane by covalent linkage. Mult-hydroxyl-layer was generated and remained steadily on TFC membrane surface after modification. The contact angle decreased from 75.9 ± 3.0° to 46.9 ± 2.3°, which showed a distinct improvement of membrane surface hydrophilicity after modification. The grafted THAM improved water flux by 28.3%, while salt rejection was almost unchanged in membrane property tests. The modified membranes presented preferable antifouling property to foulants of bovine serum albumin, sodium alginate, and dodecyl trimethyl ammonium bromide than that of pristine membranes during dynamic fouling experiments. The method in this study provided an effective way to improve antifouling property of the polyamide thin-film-composite RO membrane. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45891. [ABSTRACT FROM AUTHOR]

ABSTRACT The high shrinkage and the low impact strength severely limit the applications of the isotactic polypropylene (iPP). In this article, we studied the shrinkage, microstructure, and mechanical properties of the composites consisted of iPP, short glass fiber (GF), maleic anhydride grafted polypropylene (MPP), maleic anhydride grafted polypropylene/polyolefin elastomer (MPPPOE) or composite toughening agents (CTAs). The results show that the shrinkage of the composite with 40% GF reduces to 0.0754% (24 h) and 0.0893(48 h), respectively, under room temperature, which is far lower than the shrinkage [1.782% (24 h) and 1.821% (48 h)] of the pure iPP. For the composite of PP/GF/MPPPOE/CTAs (55/30/5/10), the tensile strength increases to 65.53 MPa (33.8 MPa for pure iPP), the tensile modulus is 1445 MPa which is 136% higher than pure iPP, and the izod impact strength reaches 22.72 kJ/m2 (only 5.28 kJ/m2 for pure iPP). Not only the scale stability of iPP is remarkably improved, but also the comprehensive mechanical properties are enhanced drastically. This work may generate potential opportunities for iPP in those applications demanding high scale stability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44275. [ABSTRACT FROM AUTHOR]

The improvement in the toughness of isotactic polypropylene by introducing ultrahigh molecular weight polyethylene and further blending it with compounded α/β nucleation agents were studied. According to the results, the polyethylene with higher molecular weight and dissolving method have affected the toughening of isotactic polypropylene. For isotactic polypropylene/nucleation agent blend, the Izod impact strength increases by 93.5% with a slight decrease in the tensile strength. When both nucleation agents and polyethylene are added, the synergistic toughening effect is more remarkable, and the Izod impact strength is about 232% higher than that of pure isotactic polypropylene. [ABSTRACT FROM AUTHOR]

The HIV-1 epidemic among men who have sex with men (MSM) has been spreading throughout China. Shanghai, a central gathering place for MSM, is facing a continuously increasing incidence of HIV-1 infection. In order to better understand the dynamics of HIV-1 diversity and its influence on patient’s immune status at baseline on diagnosis, 1265 newly HIV-1-infected MSM collected from January 2009 to December 2013 in Shanghai were retrospectively analyzed for genetic subtyping, CD4+T cell counts, and viral loads. HIV-1 phylogenetic analysis revealed a broad viral diversity including CRF01_AE (62.13%), CRF07_BC (24.51%), subtype B (8.06%), CRF55_01B (3.24%), CER67_01B (0.95%), CRF68_01B (0.4%), CRF08_BC (0.08%) and CRF59_01B (0.08%). Twenty-four unique recombination forms (URFs) (1.98%) were identified as well. Bayesian inference analysis indicated that the introduction of CRF01_AE strain (1997) was earlier than CRF07_BC strain (2001) into MSM population in Shanghai based on the time of the most recent common ancestor (tMRCA). Three epidemic clusters and five sub-clusters were found in CRF01_AE. Significantly lower CD4+T cell count was found in individuals infected with CRF01_AE than in those infected with CRF07_BC infection (P<0.01), whereas viral load was significantly higher those infected with CRF01_AE than with CRF07_BC (P<0.01). In addition, the patients with >45 years of age were found to have lower CD4+T cell counts and higher viral loads than the patients with <25 years of age (P<0.05). This study reveals the presence of HIV-1 subtype diversity in Shanghai and its remarkable influence on clinical outcome. A real-time surveillance of HIV-1 viral diversity and phylodynamics of epidemic cluster, patient’s baseline CD4+T cell count and viral load would be of great value to monitoring of disease progression, intervention for transmission, improvement of antiretroviral therapy strategy and design of vaccines. [ABSTRACT FROM AUTHOR]

Understanding the mechanism of ion rejection in the separation process remains a major hurdle in designing new membrane materials for seawater desalination. Here, we investigate the effects of water and aromatic polyamide (PA) membrane on the rejection of salt ions, such as Fe2+, Na+, and Cl−, by molecular dynamic simulations. Results demonstrate that water plays a key role in salt ion rejection because salt ions preferentially interact with water molecules to form hydrates with multishell structures, which aids the rejection of various salt ions. For FeCl2 aqueous solution, the innermost shell water molecules of a Fe2+ hydrate can hardly be replaced by other substances in their molecular dynamics simulations, so ions would be highly rejected if the effective diameter of a water channel (EDC) in the membrane is smaller than that of the innermost shell of a hydrate. However, the water molecules in the second water shell can be replaced by the atoms of the membrane when the EDC is smaller than the size of the second shell (about 9 Å). Besides, although the sizes of these ions approximate to those of water molecules, the rejection level of PA membrane to salt ions is higher than that to water, which is accounted for by the formation of hydrate. POLYM. ENG. SCI., 55:466-473, 2015. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

As an emerging technology, forward osmosis (FO) has shown great promise in energy production from the mixing of fresh water and seawater in estuaries. However, the power density levels of the present commercial FO membranes hinder their practical applications in power generation due to the requirement for extremely large areas of membrane. Here, we use functionalized porous-single-layer graphene as a FO membrane and study the transport performances of the membrane using molecular dynamics simulation. For the FO system using fluorinated porous graphene (pore-diameter 11.7 Å, porosity 10%), with an excellent performance for salt rejection, the water flux is 28.1 L cm−2 h which is about 1.8 × 104 times higher than that of a typical cellulose triacetate membrane. Such high water flux will certainly bring about a very high power density in pressure retarded osmosis power generation. This work may generate potential opportunities for functionalized graphene in FO power generation, seawater desalination and so forth. [ABSTRACT FROM AUTHOR]

Men who have sex with men (MSM) have recently accounted for an alarmingly increasing proportion of HIV-1 transmission in China. In order to investigate the immune status as a result of CRF01_AE infection and CXCR4 co-receptor usage in a young Shanghai-based HIV-1-infected MSM population in Shanghai, 364 HIV-1-infected MSM with average age of 22.7 years old, newly diagnosed between Jan 2009 and Jul 2013 were analyzed for CD4+T cell count, subtyping using phylogenetic analysis, and viral co-receptor tropism using Geno2pheno and webPSSM in combination. A total of 276 individuals were identified as recently infected. Subtype assignment were as follows: 176 (63.8%) CRF01_AE, 77 (27.9%) CRF07_BC, and 23 (8.3%) subtype B. Besides, 24 second-generation recombinant strains were identified. A lower CD4+T cell count at baseline survey was observed among CRF01_AE strain-infected individuals, compared to those who were infected with CRF07_BC (P<0.01). The frequency of baseline CD4+T cell count <200 was higher and the frequency of CD4 T counts >500 lower in CRF01_AE infection than CRF07_BC infection. It is worth noting that 32.4%–40.9% of CRF01_AE strain-infected individuals were predicted to carry CXCR4-tropic viruses whereas none of CRF07_BC and subtype B were found to be as CXCR4-tropic viruses (P<0.001). As could be expected CXCR4 tropism was associated with lower CD4 T counts. This study revealed that CRF01_AE strains with high frequency of CXCR4 tropism are prevailing in the young MSM population in China and could potentially cause a severe loss of CD4+T cell count and rapid disease progression. A regular surveillance of HIV-1 subtypes, CD4+T cell count and viral co-receptor usage would be greatly beneficial for effectively monitoring disease progression, improvement of antiretroviral therapy strategy and prompt intervention of transmission. [ABSTRACT FROM AUTHOR]

Temperature window effect has been used to extrude polyethylene blends 5000s/TR-571 and bimodal polyethylene GC100s with low extrusion temperatures and pressures. Rheological results indicate that the temperature window effect occurs during the extrusions of the GC100s and blends 5000s/TR-571. For the blends 5000s/TR-571, both the temperature window and the minimum extrusion pressure dramatically decreases with increasing content of 5000s. For bimodal polyethylene GC100s, successive self-nucleation and annealing (SSA) fractionation results suggest that the pick at high temperature on the SSA curve of the extrudates obtained inside the temperature window is remarkably lower than those of the extrudates obtained outside the temperature window. This indicates that the lamellae of the extrudates obtained in the window are thinner than those obtained outside the window, which is attributed to the fact that the well-aligned chains as the result of structure memory effect can act as nucleating agent in the crystallization process. POLYM. ENG. SCI., 54:303-309, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Reducing internal concentration polarization (ICP) and increasing water flux are essential for forward osmosis (FO) efficiency. Here, we use functionalized porous-single-layer graphene as a FO membrane and study its permeation properties via molecular dynamics simulations. Our results indicate that the ICP decreases to zero during FO processes, and that the water flux of graphene oxide reaches 91.5 L per cm2 per day, which is about 1.7 × 103 times higher than that of typical cellulose triacetate FO membranes. Furthermore, no forward or reverse solutes passing through the membrane are observed when the pore-diameter is smaller than 9.4 Å. This work may bring potential opportunities for functionalized porous graphene in water desalination, FO power generation and so forth. [ABSTRACT FROM AUTHOR]

In this work, both hexene copolymerized polyethylene of TR-571 and homopolymerized polyethylene of 5000s were ram extruded using a temperature window effect. The rheological results show that the extrusion pressures abruptly drops at very narrow extrusion temperature windows for the two types of polyethylenes, but the window range (150-155°C) of TR-571 are higher about 6°C than that of 5000s, and the threshold melt velocity value (where the window effect set in) for TR-571 is remarkably lower than that of 5000s. Besides, the differential scanning calorimeter experiments indicate that the melting points ( T m) of the extrudates obtained inside the temperature window are lower 3.74-4.56°C than those obtained outside, whereas the crystallization peak temperatures ( T c) of the former are higher 3.29-3.57°C than those of the later. The crystal orientation, shown in the photographs of wide-angle x-ray diffraction and scanning electron microscope, indicates that the chain alignment induced by elongational flow in the temperature window can at least be partially maintained and leave a structure memory in the melt state. Successive self-nucleation and annealing fractionation results suggest that these well-aligned chains as the result of structure memory effect can act as a nucleating agent in the crystallization process. Thus, the number of the lamellae increases and the thickness decrease, which finally leading to higher T c and lower T m of extrudates obtained inside a temperature window. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

In the present study, we investigated the influences of polymerization and crosslinking technologies on the branched-chain structures, crystallization behaviors, and gel networks of two types of low-density polyethylenes, LDPE1 and LDPE2, polymerized under different polymerization conditions in commercial large-capacity production lines. High temperature 13C NMR analysis suggests that the molar contents of both long-chain branches and short-chain branches of LDPE2 were markedly higher than those of LDPE1 due to a higher polymerization temperature for LDPE2. The high content of chain branches of LDPE2 leads to its relatively higher storage modulus, entanglement density, and gel content, as indicated by dynamic mechanical analysis. In addition, when the crosslinking temperature reached 180°C, the LDPE2 crosslinked with 2 wt% dicumylperoxide (XLPE2-D2) displayed a relatively wider processing time window and a faster crosslinking rate than XLPE1-D2. Successive self-nucleation and annealing fractionation indicated that increasing the concentration of dicumylperoxide can improve the crosslinking degree, but resulted in lower crystallinity and thinner lamellar crystals. [ABSTRACT FROM PUBLISHER]

Numerous studies suggest that two-phase morphology and thick interface are separately beneficial to the viscosity reduction and mechanical property maintainence of the matrix when normal molecular weight polymer (NMWP) is used for modification of ultrahigh molecular weight polyethylene (UHMWPE). Nevertheless, it is very difficult to obtain a UHMWPE/NMWP blend which may demonstrate both two-phase morphology and thick interface. In this work, dissipative particle dynamics simulations and Flory-Huggins theory are applied in predicting the optimum NMWP and the corresponding conditions, wherein the melt flowability of UHMWPE can be improved while its mechanical properties can also be retained. As is indicated by dissipative particle dynamics simulations and phase diagram calculated from Flory-Huggins theory, too small Flory-Huggins interaction parameter ( χ) and molecular chain length of NMWP ( N) may lead to the formation of a homogeneous phase, whereas very large interfacial tension and thin interfaces might also appear when parameters N and χ are too large. When these parameters are located in the metastable region of the phase diagram, however, two-phase morphology occurs and interfaces of the blends are extremely thick. Therefore, metastable state is found to be advisable for both the viscosity reduction and mechanical property improvement of the UHMWPE/NMWP blends. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A recent article on bulk-service queues gives a generating function for the steady-state probabilities of the embedded Markov chain for a single-server infinite-space system in which, the customers arrive according to a Poisson process and are served in batches with quorum a and capacity b, and the service time follows a general distribution dependent on batch size. This system is equivalent to the bulk queueing model M/Gj(a,b)/1, whose general solution requires finding the roots of the denominator of the underlying generating function. The article claims that the use of roots may result in numerical inaccuracies, especially for large values of b. Hence it only solves for the finite-space model M/Gj(a,b)/1/(B + b) using (B + 1) simultaneous linear equations. We present a simple way to obtain the probability distribution of queue length at post-departure epochs for the infinite-space model M/Gj(a,b)/1 using roots, then an alternative method to solve the finite-space queue M/Gj(a,b)/1/(B + b). We derive, for the first time, closed-form formulas for the queue-length distribution of models with deterministic service time for both infinite (M/Dj(a,b)/1) and finite-space (M/Dj(a,b)/1/(B + b)) systems. We also show that the queue-length distribution of M/Dj(a,b)/1 can be approximated by a Poisson distribution when the traffic intensity ρ is low. Numerical results are both tabulated and graphed. [ABSTRACT FROM AUTHOR]

The gas-phase ion pair SN2 reactions at saturated sulfur LiX + CH3SY → CH3SX + LiY (X, Y = F, Cl, Br, I) are investigated using the CCSD(T) calculations. The calculated results show that the reactions LiX + CH3SY are exothermic only when the nucleophile is a heavier lithium halide. Central barrier heights are found to depend primarily on the identity of nucleophile LiX, decreasing in the order LiF > LiCl > LiBr > LiI. Another interesting feature of the ion pair reactions at sulfur is the good correlation between the reaction barriers with geometrical looseness of Li&bond;X and S&bond;Y bonds in the transition state structures. The data for the reaction barriers show good agreement with the prediction of the Marcus equation and its modification. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [ABSTRACT FROM AUTHOR]

Gas-phase anionic reactions X- + CH3SY (X, Y = F, Cl, Br, I) have been investigated at the level of B3LYP/6-311+G (2df,p). Results show that the potential energy surface (PES) of gas-phase reactions X- + CH3SY (X, Y = Cl, Br, I) has a quadruple-well structure, indicating an addition–elimination (A–E) pathway. The fluorine behaves differently in many respects from the other halogens and the reactions F- + CH3SY (Y = F, Cl, Br, I) correspond to deprotonation instead of substitution. The gas-phase reactions X- + CH3SF (X = Cl, Br, I), however, follow an A–E pathway other than the last two out going steps (COM2 and PR) that proceeds via a deprotonation. The polarizable continuum model (PCM) has been used to evaluate the solvent effects on the energetics of the reactions X- + CH3SY (X, Y = Cl, Br, I). The PES is predicted to be unimodal in the solvents of high polarity. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [ABSTRACT FROM AUTHOR]

The gas-phase nucleophilic substitution reactions at saturated oxygen X- + CH3OY (X, Y = Cl, Br, I) have been investigated at the level of CCSD(T)/6-311+G(2df,p)//B3LYP/6-311+G(2df,p). The calculated results indicate that X- preferably attacks oxygen atom of CH3OY via a SN2 pathway. The central barriers and overall barriers are respectively in good agreement with both the predictions of Marcus equation and its modification, respectively. Central barrier heights (ΔHXY≠ and ΔHYX≠) correlate well with the charges (Q) of the leaving groups (Y), Wiberg bond orders (BO) and the elongation of the bonds (O&bond;Y and O&bond;X) in the transition structures. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [ABSTRACT FROM AUTHOR]

Aiming at preparing high‐performance polyamide (PA) reverse osmosis (RO) membrane in a facile and high effective way, the codeposition strategy of dopamine and zwitterionic polymer was first applied to modify PA RO membrane. The noncovalent bonds between dopamine and Poly [2‐(Methacryloyloxy)ethyl]dimethyl‐(3‐sulfopropyl)ammonium hydroxide (PSPE) act to fix PSPE onto the membrane surface and simultaneously destroy the interaction force between dopamine aggregations so that the modified layer could equably form on the PA layer. PSPE significantly improved the hydrophilicity [the water contact angle (WCA) of S‐D‐3 is 25.3°] of the modified membrane. And, the smoother surface was noticed on the modified membrane. All of these endow the PSPE/dopamine modified membrane superb water flux (the maximum water flux is 51.86 L m−1 h−1 at 1.6 MPa and 25 °C) and impressive antifouling and anti‐adhesion properties to bovine serum albumin (BSA) (protein), sodium dodecyl sulfate (anionic surfactant), and dodecyl trimethyl ammonium bromide (cationic surfactant) with salt retention was well maintained. Notably, in the BSA fouling test, nearly 100% of the flux recovery ratio was achieved. This method is promising to be employed in industrial scale‐up production. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48355. [ABSTRACT FROM AUTHOR]

The organic fouling of polyamide membranes is one of the most serious problems in reverse osmosis fields such as sea water desalination and sewage disposal. In this study, poly(ethylene imine)–poly(ethylene glycol) dendrimer is used to improve the fouling resistance of polyamide reverse osmosis membranes. A crucial pretreatment is carried out with a reaction between poly(ethylene imine) and acyl chloride on the nascent polyamide surface, generating an amine‐rich selective layer. Poly(ethylene glycol) diglycidyl ether is then attached to the primary amine group. The results illustrate a remarkable improvement in membrane surface hydrophilicity after modification (the contact angle decreases from 96.7° to 49.5°). Dynamic fouling tests are implemented with bovine serum albumin as a typical protein foulant, in which the membranes show very low protein adsorption (flux recovery ratio 96.9%). After 11‐cycle fouling tests, the membranes show excellent long‐term stability and remarkable antifouling property and cleaning performance. This approach of grafting a dendrimer might provide new insight for antifouling modifications for membranes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47368. [ABSTRACT FROM AUTHOR]