Biomethane generation from biogas upgrading by means of thin-film composite membrane comprising Linde T and fluorinated polyimide: optimization of fabrication parameters

Generation of biogas from organic substances is an attractive evolution of energy generation from fossil-based energy supply to renewable resources. In order to exhibit viability in terms of technical execution while being economically feasible, successful purification strategies for biomethane formation must be applicable to industrial gas streams at realistic pressures and temperatures. Membrane-based upgrading technologies have great potential to promote biogas processes because they involve less energy and low maintenance. However, the development of membranes with good polymer-filler contact and minimum defects remains a great challenge. Hitherto, researchers have been making many attempts at developing an established route to fabricate thin-film composite membranes. In the present work, an innovative coupling between Linde T and fluorinated polyimide was employed for biogas upgrading. A facile technique for membrane fabrication was proposed via optimization of the fabrication parameters. The results indicated that composite membrane fabricated with 2 hours of total dispersion duration demonstrated a homogeneous distribution of Linde T particles in the fluorinated polyimide matrix and improved the separation characteristics by up to 172% in upgrading biomethane quality. Thus, the fabricated membrane is feasible to be employed for large-scale and lucrative production with enhanced performance in biogas purification via the feasible fabrication method employed in this work.

Generation of biogas from organic substances is an attractive evolution of energy generation from fossil-based energy supply to renewable resources.     

Usefulness of the total cholesterol to high-density lipoprotein cholesterol ratio in predicting angiographic coronary artery disease in women

To investigate the relation between lipids and angiographic coronary artery disease (CAD) in women, fasting lipid profiles were obtained on 108 women undergoing coronary angiography (group I). CAD, defined as ≥25% luminal diameter narrowing in a major coronary artery, was present in 57 (53%). Neither serum total cholesterol nor triglyceride levels correlated with the presence of CAD. Mean total/high-density lipoprotein (HDL) cholesterol ratio was higher among women with than without CAD (5.5 ± 0.3 vs 4.2 ± 0.2, p < 0.0001). Multiple regression analyses identified a higher total/HDL cholesterol ratio as the variable most predictive of the presence (p < 0.001), extent (number of narrowed arteries) (p < 0.0001), and severity (% maximum stenosis) (p < 0.001) of CAD. Age and lack of estrogen use were also independently associated with the presence of CAD, age and lowdensity lipoprotein cholesterol level were additional indicators of extent, and age was the only other discriminator of severity of CAD.

In 56 women with total cholesterol <200 mg/dl (group II), mean total/HDL cholesterol ratio was higher in women with (n = 24) than without CAD (4.3 ± 0.2 vs 3.5 ± 0.2, P = 0.01). Higher total/HDL cholesterol ratio was the variable most predictive of the presence of CAD (p = 0.01), and the tone variable associated with severity (p < 0.001) after adjustment for other risk factors. Age was independently associated with presence and extent, and hypertension was also independently related to extent. Thus, among these women, total/HDL cholesterol ratio is the best predictor of the presence, severity and extent of CAD in general, and is the best predictor of presence, and severity in patients with total cholesterol <200 mg/dl.     

Evaluation of Radiation Resistance of Polystyrene Using Molecular Dynamics Simulation

The scission rates of polystyrene and fluorinated polystyrene irradiated in an irradiation facility with Co-60 γ-rays were determined using molecular dynamics simulation and gel permeation chromatography (GPC) molecular weight distributions. The prediction was based on the assumption that γ-ray energy is transferred to the initial velocity of the primary knock-on atom. We employed a molecular dynamics simulation procedure to compute the changes in bond length between the connections for selected values of the absorbed dose and compared the calculated values with measurements made on the irradiated samples. The samples were exposed to four different absorbed doses of 25, 50, 75, and 100 kGy. The scission process and scission ratio were simulated with LAMMPS with ReaxFF potential for each bond, and we compared the simulation results with the experimental data especially measuring average molecular weight to evaluate the effect of fluorination on radiation enhancement.     

Alteration of intramolecular electronic transition via deboronation of carbazole-based o-carboranyl compound and intriguing ‘turn-on’ emissive variation

The conversion of closo-o-carborane–containing compounds to the nido-o-species via deboronation causes photophysical changes that could be used for sensing applications. 9-Methyl-9H-carbazole–based closo- (closo-Cz) and nido-o-carboranyl (nido-Cz) compounds were prepared and fully characterised by multinuclear NMR spectroscopy and elemental analysis, and the solid-state molecular structure of closo-Cz was analysed by X-ray crystallography. Although the closo-compound exhibited an emissive pattern centred at λ_em = ca. 530 nm in the rigid state only (in THF at 77 K and as a film), nido-Cz demonstrated intense emission in the near-UV region (λ_em = ca. 380 nm) in both solution and film states at 298 K. The positive solvatochromic effect of nido-Cz and the results of theoretical calculations for both the o-carboranyl compounds supported that these emissive features originate from intramolecular charge transfer (ICT) corresponding to the o-carborane. Furthermore, the calculations verified that the electronic role of the o-carboranyl unit changed from acceptor to donor upon deboronation from closo-Cz to nido-Cz. Investigations of the radiative decay mechanisms of closo-Cz and nido-Cz according to their quantum efficiencies (Φ_em) and decay lifetimes (τ_obs) suggested that the ICT-based radiative decays of closo-Cz and nido-Cz readily occur in the film (solid) and solution state, respectively. These observations implied that the emission of closo-Cz in the solution state could be drastically enhanced by deboronation to nido-Cz upon exposure to an increasing concentration of fluoride anions. Indeed, turn-on emissive features in an aqueous solution were observed upon deboronation, strongly suggesting the potential of closo-Cz as a turn-on and visually detectable chemodosimeter for fluoride ion sensing.

Deboronation of a 9-methyl-9H-carbazole–based closo-o-carboranyl compound to the nido-o-carborane in an aqueous solution results in a ratiometric turn-on response in the deep-blue emission region with moderate reactivity.     

Surgical management of lipomas: Proposal of the Z‐incision design and surgical algorithm based on tumor size

Surgical excision is the treatment of choice for lipomas. However, linear incision methods or minimal extraction techniques often do not provide a sufficient surgical view. Therefore, removing large lipomas is often difficult. To present the Z‐incision and half Z‐incision designs for lipoma extraction, this retrospective study analyzed lipomas surgically excised at our institution between September 2015 and December 2018. The area of surgical field exposed by the Z‐incision versus that exposed by the linear incision was calculated using a schematic model. Cure rate, complications, and surgical field area were investigated. A total of 84 lipomas were included. A Z‐ or half Z‐incision was used to treat 30 lipomas, while a linear incision was used to treat 54 lipomas. The mean diameter of the mass in the Z‐ or half Z‐incision group was 47.7 mm (range, 15–160 mm), larger than that in the linear incision group (25.5 mm; range, 7–59 mm) (p < .001). The Z‐incision involved making rectangular windows by lifting 2 triangular flaps. According to our mathematical model, the Z‐incision provided a larger surgical field area than that provided by the linear incision based on stretched angles (1.81 times larger at 30° and 3.14 times larger at 15°). The Z‐ and half Z‐incisions were successfully performed in all but 1 lipoma (29 lipomas, 96.7%). There was 1 lipoma that resulted in postoperative complications (seroma, 3.3%). The Z‐incision design can be a useful alternative technique for the extirpation of lipomas, especially large lipomas. Here, we proposed a surgical algorithm for lipoma surgery based on tumor size.     

Swine as a principal reservoir of hepatitis E virus that infects humans in eastern China

BACKGROUND AND METHODS: Genotype IV hepatitis E virus (HEV) has been isolated from humans and swine. To study the relationship between the human and swine reservoirs, we estimated their respective viral burden, analyzed the genetic makeup of the virus populations, and assessed the risk of infection associated with swine farming. RESULTS: In 2 swine-farming districts of eastern China, 9.6% of swine and 0.3% of healthy human subjects excreted HEV in stool, as did 68.8% of patients with confirmed HEV infection. The virus population circulating in humans consisted of genotype I and at least 4 phylogenetically distinct subgroups of genotype IV viruses, 2 of which concurrently circulated among swine. Persons engaged in occupations related to swine farming were found to have a 74% higher risk of infection than those engaged in other occupations, and persons living in communities downstream of the swine farms were found to have a 29% higher risk of infection than persons living in communities upstream. CONCLUSIONS: Genotype IV HEV is freely transmitted between humans and swine. Because the size of the swine population and its viral burden are much larger than those of humans, transmission of the virus most likely is directed from swine to humans. Infection can be acquired through contact with swine and their waste.