Synergistic anionic/zwitterionic mixed surfactant system with high emulsification efficiency for enhanced oil recovery in low permeability reservoirs

Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.

Water, Sanitation and Hygiene in Lower-Level Health Care Facilities of Dar es Salaam Region in Tanzania: Status towards Achieving the Sustainable Development Goals and Way Forward

Background: Improving Water, Sanitation and Hygiene in health care settings is a critical prerequisite for achieving national health goals and Sustainable Development Goals (SDGs). The World Health Organization (WHO) has set a target for each United Nations member state to reach by 2030. Each member state is required to reach by 2022, 2025 and 2030 at least 60%, 80% and 100%, respectively of basic level of service of the five elements which are water, sanitation, hygiene, waste management and environmental cleaning. Methods: This study aimed to evaluate and document the current state of basic water, sanitation, and hygiene services in all lower-level health care facilities in the Dar es Salaam region of Tanzania as of July 2022. A cross-sectional study was conducted in 99 public dispensaries in the Dar es Salaam region’s five councils: Ubungo, Kigamboni, Kinondoni and Temeke Municipalities, and Ilala City. The interviewee form and observational checklists were both digitalized using the Kobo tool software. The respondents were health care facility in-charges or nurse in-charges. Data were downloaded, validated, and imported to Stata version 15 for analysis. Results: The basic WASH level per JMP is far below the target in 2022. Each member state by 2022 is required to reach at least 60% of the basic level of service of each element. We found a low coverage of basic WASH in the 99 dispensaries included in this study. The basic WASH coverage was met in only 10 (10.1%) of the dispensaries, while the remaining 89 (89.9%) dispensaries fall on limited WASH services. Conclusion: This study revealed lower coverage of basic WASH services in dispensaries. An urgent need is required to improve the status of WASH in all the dispensaries and facilitate the provision of quality health care services, patient safety and reduce health care associated infections.

Effect of low concentration electrolytes on the formation and corrosion resistance of PEO coatings on AM50 magnesium alloy

In this paper,the formation process,morphology,and electrochemical performance of PEO coatings on AM50 magnesium alloy prepared in low concentration phosphate,aluminate,and phosphate-aluminate electrolytes were systematically studied.The results show that the coatings prepared from the phosphate electrolytes have a higher thickness and better corrosion resistance properties compared to the other electrolytes.The coatings prepared from low concentration phosphate-aluminate mixed electrolytes have slightly thinner thickness,a similar coating structure and an order of magnitude lower value of electrochemical impedance compared with phosphate electrolyte coatings.The Coatings prepared from low concentration aluminate electrolytes have the lowest thickness and the worst corrosion resistance properties which gets close to corrosion behavior of the bare AM50 under the same test conditions.Considering application,coatings prepared from single low concentration phosphate electrolytes and low concentration phosphate-aluminate electrolytes have greater potential than single low concentration aluminate coatings.However,reducing the electrolyte concentrations of coating forming ions too much has negative influence on the coating growth rate.

Simultaneous type III congenital esophageal atresia and patent ductus arteriosus in a low-weight patient: A case report

BACKGROUND We report a low-birth-weight child(1.8 kg)with neonatal type III congenital esophageal atresia(CEA)combined with symptomatic patent ductus arteriosus(PDA).After comprehensive evaluation,esophageal anastomosis was performed on postnatal day 11 after excluding surgical contraindications,and arterial catheter ligation was performed at the same time.Concurrent surgery for CEA combined with PDA has not been clearly reported in the literature.CASE SUMMARY We report a 6-day-old female child with type III CEA and PDA.The patient presented with foam at the mouth after birth,cough and shortness of breath after feeding.At another hospital,she was considered to have neonatal pneumonia,neonatal jaundice and congenital heart disease and transferred to our hospital.After iodine oil radiography of the esophagus and echocardiography we con-firmed diagnosis of CEA and PDA.The diameter of the PDA was 8 mm,with obvious left to right shunting.We performed right rear extrapleural orificium fistula ligation and esophageal anastomosis,and ligation of PDA via left axilla straight incision after 5 d of hospitalization.The operations were successful,and the incision healed after 12 d,and the patient was discharged.We re-examined the patient 1 mo after surgery.She did not vomit when she ate rice flour.Esophageal angiography showed no stricture of the anastomotic stoma.The patient weighed 3.2 kg.CONCLUSION For CEA patients with multiple risk factors,comprehensive,timely and accurate diagnosis and evaluation,and early treatment may improve prognosis.

Evaluation of Cold Resistance and Semi-lethal Low Temperature(LT_(50))of Nine Pear Cultivars

[Objectives]To evaluate the cold resistance and semi-lethal temperature of pear cultivars,and provide a theoretical basis for the regional extension and breeding of cold-resistant pear cultivars.[Methods]Nine pear cultivars were used to study the changes in relative conductivity and cell injury rate of pear branches under low temperature stress,and the semi-lethal temperature(LT_(50))of pear branches was analyzed by fitting Logistic equation.[Results]The relative conductivity and cell injury rate of pear branches took on the trend of slow increase,rapid increase,and slow increase the decrease of treatment temperature.The LC_(50) of the nine pear cultivars were as follows:Nanguo pear-33.9℃,Wanyu-32.3℃,Red D Anjou-31.8℃,Jinfeng-31.3℃,Wujiuxiang-29.2℃,20 th Century Pear-29.1℃,Hanxiang-35.1℃,Yuluxiang-27.9℃ and Korla Fragrant Pear-29.2℃.[Conclusions]The semi-lethal temperature could reflect the cold resistance of pear trees,and Wanxiang had better cold resistance.The evaluation of cold resistance and semi-lethal temperature of pear cultivars can provide theoretical basis for regional extension and breeding of cold-resistant pear cultivars.

Low Level of Cystic Fibrosis Transmembrane Conductance Regulator Is Associated with Human Sperm Autophagy and Vitality

Low sperm motility is one of the main causes of male infertility. Cystic fibrosis transmembrane conductance regulator (CFTR, an anion channel protein) is related to the progressive motility of sperm. CFTR disruptor CFTRinh-172 or forskolin (FSK) in this study were used to treat human sperm separately, and the rates of sperm autophagy and progressive motility, mitochondrial membrane potential (MMP) and ATP concentration, and the expression levels of related factors were detected to explore their relationship. It was showed that sperms treated with CFTRinh-172 or FSK reduced the levels of cAMP, CFTR and PKA, but increased sperm autophagy rate, expression levels of AMPK and LC3B. However, reactive oxygen species content had no significant difference. It was indicated that low level of CFTR performed with cAMP and its downstream effectors such as PKA and AMPK to regulate mitochondrial structure and function, leading to increased autophagy rate and reduced vitality of sperm.

Investigation of bubbles escape behavior from low basicity mold flux for high-Mn high-Al steels using 3D X-ray microscope

During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.

Antioxidase System of a Rice Mutant with Low Chlorophyll b

[Objective] The mitigative effect of antioxidase system of a rice mutant with low chlorophyll b on photooxidative damage was studied.[Method] A rice mutant with low chlorophyll b and its wild type were taken as experimental materials to comparatively research their peroxide (H2O2) contents, the activity and isozymes of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in chloroplast.[Result] Compared with the wild type, there were many kinds of SOD, POD and CAT isozymes in leaf cells and chloroplast cell of mutant, and the activity of SOD, POD and CAT isozymes in leaf cells and chloroplast cell of mutant was also correspondingly higher. Under intense light condition, the H2O2 content of chloroplast in mutant was less than that in the wild type. [Conclusion] The higher activity of scavenging active oxygen can relieve the photooxidative damage made by excessive light energy of intense light on photosynthetic membrane, which is an important reason for higher photosystem Ⅱ (PS II) stability of this mutant.

Synthesis and Characterization of SiCOF/a-C∶F Double-Layer Films with Low Dielectric Constant for Copper Interconnects~*

A novel double-layer film of SiCOF/a-C ： F with a low dielectric constant is deposited using a PECVD system. The chemical structure of the film is characterized with Fourier transform infrared spectroscopy （FTIR）. The measurements of the film refractive index reveal that the optical frequency dielectric constant （n^2） of the film is almost constant as a function of air exposure time, however, with increasing annealing temperature, the value of n^2 for the film decreases. Possible mechanisms are discussed in detail. The analysis of SIMS profiles for the metal-insulator-silicon structures reveal that in the Al/a-C ： F/Si structure,the annealing causes a more rapid diffusion of F in AI in comparison with C, but there is no obvious difference in Si. In addition, no recognizable verge exists between SiCOF and a-C ： F films,and the SiCOF film acts as a barrier against the diffusion of carbon into the aluminum layer.

Growth and crystallization behaviors of anodic oxide films on sputter-deposited titanium at very low potentials

Growth and crystallization of titanium anodized films were studied by performing the anodization of the sputter-deposited titanium samples under cyclic voltammetry （CV） mode at very low potentials. The surface features, crystalline behaviors and chemical compositions of the formed anodic oxide layers were detected by AFM, SE and XPS. It was found that the structure of the titanium anodized films is crystalline, even though the maximum oxidation potential （（Pmax） is very low （as low as 1000 mY）. Both enlarging the applied voltage and reducing the potential scanning rate are beneficial for the growth and crystallization of titanium oxide films. It was thought that the internal compressive stress, other than the local joule heating accepted for many researchers, is the main force of stimulating the crystallization of anodic titanium oxide films at very low potentials.

Variety Test on Low Temperature-resistant Pleurotus ostreatus Strains in Beijing Area

With 7 familiar Pleurotus ostreatus strains in Beijing region as the test materials,the randomized block design method was adopted to analyze the antagonistic effects,mycelial growth rate,yield of mushroom at low temperature season,total biological efficiency and agronomic characteristics of fruit bodies.The results showed that there were antagonistic effects and differences in all the tested items between all the tested strains,of which the strain PL5 had the shortest spawn age,the strain PL3 showed the highest total biological efficiency,and the fructification of the strain PL7 tasted crisp and tender.

Low cycle fatigue behavior of laser melting deposited TC18 titanium alloy

Low cycle fatigue （LCF） behavior of laser melting deposited （LMD） TC18 titanium alloy was studied at room temperature. Microstructure consisting of fine lamella-like primary α phase and transformed β matrix was obtained by double annealed treatment, and inhomogeneous grain boundaryαphase was detected. Fatigue fracture surfaces and longitudinal sections of LCF specimens were examined by optical microscopy and scanning electron microscopy. Results indicate that more than one crack initiation site can be detected on the LCF fracture surface. The fracture morphology of the secondary crack initiation site is different from that of the primary crack initiation site. When the crack grows along the grain boundaryαphase, continuous grain boundaryαphase leads to a straight propagating manner while discontinuous grain boundaryαphase gives rise to flexural propagating mode.

Isolation and Genetic Analysis of Arabidopsis Mutants with Low_K^+ Tolerance

Ethyl methane-sulfonate (EMS)-mutagenized Arabidopsis M-2 populations were screened in low-K+ medium using the root-bending assay. Forty-two putative low-k(+)-tolerant (lkt) mutants were selected from 150 000 tested M-2 seedlings, and two of these mutants maintained their low-K+-tolerant phenotype in their M-3 generations, respectively. Genetic analysis showed that either one of these two mutants has a monogenic recessive mutation in a nuclear gene, and that the two mutations in two independent mutants are allelic to each other.

Influence of mill scale and rust layer on the corrosion resistance of low-alloy steel in simulated concrete pore solution

Electrochemical impedance spectroscopy, cyclic potentiodynamic polarization measurements, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to investigate the influence of mill scale and rust layer on the passivation capability and chloride-induced corrosion behaviors of conventional low-carbon（LC） steel and low-alloy（LA） steel in simulated concrete pore solution. The results show that mill scale exerts different influences on the corrosion resistance of both steels at various electrochemical stages. We propose that the high long-term corrosion resistance of LA steel is mainly achieved through the synergistic effect of a gradually formed compact, adherent and well-distributed Cr-enriched inner rust layer and the physical barrier protection effect of mill scale.

Study on Low Density and Heat-resistant Ablative Coating

Low bulk density expanding vermiculite is prepared, and the surface modification of hollow Al2O3-SiO2 microspheres and the composition of the low density ablative coating are studied. Organic silicon epoxy resin and phenolic aldehyde resin are applied as film forming matters to get a series of ablative coating having a density of 0.4-0.6 g/cm^3. The performance of the low density ablative coating is evaluated by mechanical, thermodynamic and oxygen acetylene ablation tests, and the results are as follows, adhesion is in the range of 2.97-4.63 MPa, conductivity is no more than 0.1 kcal/（m·h·℃ ）, line ablation rate is no more than 0.30 mm/s, mass ablation rate is in the range of 0.11-0.18 mm/s.

Influence of Ar/N_2 Flow Rate on Structure and Property for TaN/NbN Multilayered Coatings

TaN/NbN multilayered coatings with nanoscale bilayer periods were synthesized at different Ar/N2 flow rates by RF （radio frequency） magnetron sputtering. XRD （X-ray diffraction） and Nano Indenter System were employed to investigate the influence of Ar/N2 flow rate （FAr：FN2） on microstructure and mechanical properties of the coatings. The low-angle XRD pattern indicated a well-defined composition modulation and layer structure of the multilayered coating. All multilayered coatings almost revealed higher hardness than the rule-of-mixtures value of monolithic TaN and NbN coatings. At FAr：FN2=10, the multilayered coating possessed desirable hardness, elastic modulus, internal stress, and fracture resistance, compared with ones synthesized at other Ar/N2 flow rates. The layered structure with strong mixture of TaN （110）, （111）, （200） and Nb2N （101）textures should be related to the enhanced mechanical properties.

Determination of Nickel and Palladium in Environmental Samples by Low Temperature ETV-ICP-OES Coupled with Liquid-liquid Extraction with Dimethylglyoxime as Both Extractant and Chemical Modifier

A novel method for the determination of nickel and palladium in environmental samples by low temperature ETV-ICP-OES with dimethylglyoxime（DMG） as both the extractant and chemical modifier has been developed. In this study, it was found that nickel and palladium can form complexes with dimethylglyoxime（0. 05%, mass fraction） at pH 6.0 and can be extracted into chloroform quantitatively. The complexes can be evaporated into plasma at a suita-ble temperature（ 1400℃） for ICP-OES detection. Under the optimized conditions, the detection limits of nickel and palladium are 0.48 and 0. 40 ng/mL, respectively, while the RSD values are separately 5.0% and 3.1% （p = 50 ng/mL, n = 7）. The proposed method was applied to the determination of the target analytes in environmental sam-ples with satisfactory results.

Enhanced oil recovery from carbonate reservoirs by spontaneous imbibition of low salinity water

An experimental study was performed to investigate the impact of low salinity water on wettability alteration in carbonate core samples from southern Iranian reservoirs by spontaneous imbibition. In this paper, the effect of temperature, salinity,permeability and connate water were investigated by comparing the produced hydrocarbon curves. Contact angle measurements were taken to confirm the alteration of surface wettability of porous media. Oil recovery was enhanced by increasing the dilution ratio of sea water, and there existed an optimum dilution ratio at which the highest oil recovery was achieved. In addition, temperature had a very significant impact on oil recovery from carbonate rocks. Furthermore, oil recovery from a spontaneous imbibition process was directly proportional to the permeability of the core samples. The presence of connate water saturation inside the porous media facilitated oil production significantly. Also, the oil recovery from porous media was highly dependent on ion repulsion/attraction activity of the rock surface which directly impacts on the wettability conditions. Finally, the highest ion attraction percentage was measured for sodium while there was no significant change in pH for all experiments.

Responsiveness and minimal clinically important difference of the Chinese version of the Low Vision Quality of Life Questionnaire after cataract surgery

AIM: To investigate the Chinese version of the Low Vision Quality of Life Questionnaire(CLVQOL) as an instrument for obtaining clinically important changes after cataract surgery.METHODS: Patients underwent cataract surgery in Shanghai General Hospital, Shanghai Jiao Tong University, who fit the inclusion criteria were recruited. Two CLVQOLs were administered, including a preoperative CLVQOL and a CLVQOL at the end of the 3 mo follow-up period, and were completed using face-to-face interviews or phone interviews conducted by trained investigators. The minimal clinically important difference(MCID) was calculated using an anchor-based method and a distribution method. In addition, the responsiveness of the questionnaire was measured.RESULTS: A total of 155 residents were enrolled. The average visual acuity(VA) preoperatively was 0.08(SD=0.05), and it increased to 0.47(SD=0.28) at the end of followup. Statistically significant positive changes in the CLVQOL scores indicated significant improvement of vision related quality of life after cataract surgery. With the larger value between the two results as the final value, the MCID values of the CLVQOL(scores of the four scales as well as the total score) were 8.94, 2.61, 4.34, 3.10 and 17.63, respectively. The CLVQOL has both good internal and external responsiveness.CONCLUSION: CLVQOL scores are appropriate instruments for obtaining clinically important changes after cataract surgery. This study is an effective exploration for establishingcataract surgery efficacy standards, which helps clinical and scientific research workers in ophthalmology to gain a more in-depth understanding when using CLVQOL.

Influence of chromium on the initial corrosion behavior of low alloy steels in the CO_2–O_2–H_2S–SO_2 wet–dry corrosion environment of cargo oil tankers

The influence of Cr on the initial corrosion behavior of low-alloy steels exposed to a CO2–O2–H2S–SO2 wet–dry corrosion environment was investigated using weight-loss measurements, scanning electron microscopy, N2 adsorption tests, X-ray diffraction analysis, and electrochemical impedance spectroscopy. The results show that the corrosion rate increases with increasing Cr content in samples subjected to corrosion for 21 d. However, the rust grain size decreases, its specific surface area increases, and it becomes more compact and denser with increasing Cr content, which indicates the enhanced protectivity of the rust. The results of charge transfer resistance(Rct) calculations indicate that higher Cr contents can accelerate the corrosion during the first 7 d and promote the formation of the enhanced protective inner rust after 14 d; the formed protective inner rust is responsible for the greater corrosion resistance during long-term exposure.