A metallic anti-biofouling surface with a hierarchical topography containing nanostructures on curved micro-riblets

Metallic surface finishes have been used in the anti-biofouling, but it is very difficult to produce surfaces with hierarchically ordered structures. In the present study, anti-biofouling metallic surfaces with nanostructures superimposed on curved micro-riblets were produced via top-down fabrication. According to the attachment theory, these surfaces feature few attachment points for organisms, the nanostructures prevent the attachment of bacteria and algal zoospores, while the micro-riblets prohibit the settlement of macrofoulers. Anodic oxidation was performed to induce superhydrophilicity. It forms a hydration layer on the surface, which physically blocks foulant adsorption along with the anti-biofouling topography. We characterized the surfaces via scanning electron and atomic force microscopy, contact-angle measurement, and wear-resistance testing. The contact angle of the hierarchical structures was less than 1°. Laboratory settlement assays verified that bacterial attachment was dramatically reduced by the nanostructures and/or the hydration layer, attributable to superhydrophilicity. The micro-riblets prohibited the settlement of macrofoulers. Over 77 days of static immersion in the sea during summer, the metallic surface showed significantly less biofouling compared to a surface painted with an anticorrosive coating.

Prevalence and antimicrobial susceptibility of Listeria spp. isolated from bulk raw milk in north-eastern Poland

Purpose of research: The aim of the study was to determine the presence of Listeria spp. strains in the milk samples obtained from dairy farms in north-eastern Poland and to determine the profile of resistance to antibiotics recommended in the treatment of listeriosis. Material and methods: 500 samples of bulk milk were analyzed. Milk samples were obtained from dairy farms located in Warmia and Mazury region in Poland. Chronic mastitis, requiring frequent and long-term use of antibiotics has been documented in these herds. Isolation of Listeria spp. was performed according to the standard procedure PN-EN ISO 11290-1: 2017-07. Antibiotic resistance testing was performed by the disc diffusion method according to the Clinical & Laboratory Standards Institute (CLSI) recommendations. Results: In total, out of 500 samples of pooled milk, based on biochemical properties, 8 isolates were confirmed as belonging to the genus Listeria (1.6%). The further identification of Listeria strains on the basis of MicrobactListeria12L showed that 3 strains (3/8, 37.5%) belonged to L. monocytogenes species and 5 strains (5/8, 62.5%) belonged to L. innocua species. The analysis of sensitivity to commonly used antimicrobial agents showed that all isolates, both belonging to L. monocytogenes and L. innocua species, were sensitive to ampicillin. Multidrug resistance, defined as resistance to at least three classes of antibiotics, was confirmed among four isolates (50%). Research summary: The studies undertaken revealed that raw milk can pose a risk for public health due to the prevalence of pathogenic Listeria spp. among which multidrug resistant strains are present. It is therefore necessary to rationalize the use of antibiotics and to monitor bacterial resistance in the food production environment.

The Manufacture and Performance of Low Temperature Superconductors

The application of Nb3Sn superconductor joints is an important part in the production of ITER, MRI and so on. This paper first introduced the application, like coil of MRI, and basic information including the micro crystal structure of Nb3Sn superconductor, which includes the theoretical critical temperature of 18.1K, even mostly, experiments take place under 4.2K, which is the boiling point of liquid helium. Second, it talked a little about the production of CICC joints in industry. Then, mainly introduced the testing device, material parameters and testing procedures of resistance testing of Nb3Sn joints. Concluded all the data from several tests and summarized it. At last, it displayed some of its mechanical property especially about its brittle property and discussed some details in manufacture. Finally conclude about them all.

Epidemiology and Transmitted HIV-1 Drug Resistance among Treatment-Naïve Individuals in Israel, 2010–2018

Despite the low prevalence of HIV-1 in Israel, continuous waves of immigration may have impacted the local epidemic. We characterized all people diagnosed with HIV-1 in Israel in 2010–2018. The demographics and clinical data of all individuals (n = 3639) newly diagnosed with HIV-1 were retrieved. Subtypes, transmitted drug-resistance mutations (TDRM), and phylogenetic relations, were determined in >50% of them. In 39.1%, HIV-1 transmission was through heterosexual contact; 34.3% were men who have sex with men (MSM); and 10.4% were people who inject drugs. Many (>65%) were immigrants. Israeli-born individuals were mostly (78.3%) MSM, whereas only 9% of those born in Sub-Saharan Africa (SSA), Eastern Europe and Central Asia (EEU/CA), were MSM. The proportion of individuals from SSA decreased through the years 2010–2018 (21.1% in 2010–2012; 16.8% in 2016–2018) whereas those from EEU/CA increased significantly (21% in 2010–2012; 27.8% in 2016–2018, p < 0.001). TDRM were identified in 12.1%; 3.7, 3.3 and 6.6% had protease inhibitors (PI), nucleotide reverse transcriptase inhibitors (NRTI), and non-nucleoside reverse transcriptase inhibitors (NNRTI) TDRM, respectively, with the overall proportion remaining stable in the studied years. None had integrase TDRM. Subtype B was present in 43.9%, subtype A in 25.2% (A6 in 22.8 and A1 in 2.4%) and subtype C in 17.1% of individuals. Most MSM had subtype B. Subtype C carriers formed small clusters (with one unexpected MSM cluster), A1 formed a cluster mainly of locally-born patients with NNRTI mutations, and A6 formed a looser cluster of individuals mainly from EEU. Israelis, <50 years old, carrying A1, had the highest risk for having TDRM. In conclusion, an increase in immigrants from EEU/CA and a decrease in those from SSA characterized the HIV-1 epidemic in 2010–2018. Baseline resistance testing should still be recommended to identify TDRM, and improve surveillance and care.

A Fast Lasso-Based Method for Inferring Higher-Order Interactions

Large-scale genotype-phenotype screens provide a wealth of data for identifying molecular alterations associated with a phenotype. Epistatic effects play an important role in such association studies. For example, siRNA perturbation screens can be used to identify combinatorial gene-silencing effects. In bacteria, epistasis has practical consequences in determining antimicrobial resistance as the genetic background of a strain plays an important role in determining resistance. Recently developed tools scale to human exome-wide screens for pairwise interactions, but none to date have included the possibility of three-way interactions. Expanding upon recent state-of-the art methods, we make a number of improvements to the performance on large-scale data, making consideration of three-way interactions possible. We demonstrate our proposed method, Pint, on both simulated and real data sets, including antibiotic resistance testing and siRNA perturbation screens. Pint outperforms known methods in simulated data, and identifies a number of biologically plausible gene effects in both the antibiotic and siRNA models. For example, we have identified a combination of known tumor suppressor genes that is predicted (using Pint) to cause a significant increase in cell proliferation.

Resource and infrastructure challenges on the RESIST-2 Trial: an implementation study of drug resistance genotype-based algorithmic ART switches in HIV-2-infected adults in Senegal

Background Second-line treatment of HIV-2 in resource-limited settings (RLS) is complicated by a lack of controlled trial data, limited availability of HIV-2-active antiretroviral drugs, and inadequate access to drug resistance testing. We conducted an implementation trial of a dried blood spot- (DBS) based, drug resistance genotype-informed antiretroviral therapy (ART) switching algorithm for HIV-2-infected patients in Senegal. Methods HIV-2-infected adults initiating or receiving ART through the Senegalese national AIDS program were invited to participate in this single-arm trial. DBS from participants with virologic failure (defined as viral load (VL) > 250 copies/mL after > 6 months on the current ART regimen) were shipped to Seattle for genotypic drug resistance testing. Participants with evidence of drug resistance in protease or reverse transcriptase were switched to new regimens according to a pre-specified algorithm. Participant clinical and immuno-virologic outcomes were assessed, as were implementation challenges. Results We enrolled 152 participants. Ten were initiating ART. The remainder were ART-experienced, with 91.0% virologically suppressed (< 50 copies/mL). Problems with viral load testing capability resulted in obtaining VL results for only 227 of 613 (37.0%) participant-visits. Six of 115 participants (5.2%) with VL available after > 6 months on current ART regimen experienced virologic failure, with per-protocol genotypic testing attempted. One additional test was performed for a participant with a VL of 222 copies/mL. Genotypes from three participants showed no evidence of major drug resistance mutations, two showed nucleoside reverse transcriptase inhibitor (NRTI) resistance, one showed both NRTI and protease inhibitor resistance, and one test failed. No integrase inhibitor resistance was observed. Five of six successfully-tested participants switched to the correct regimen or received additional adherence counseling according to the algorithm; the sixth was lost to follow-up. Follow-up VL testing was available for two participants; both of these were virally suppressed (< 10 copies/mL). The trial was terminated early due to the COVID-19 pandemic (which prevented further VL and genotypic testing), planned rollout of dolutegravir-based 1st-line ART, and funding. Conclusions The RESIST-2 trial demonstrated that a DBS-based genotypic test can be used to help inform second-line ART decisions as part of a programmatic algorithm in RLS, albeit with significant implementation challenges. Trial registration ClinicalTrials.govNCT03394196. Registered on January 9, 2018.

ĐÁNH GIÁ IN VITRO KHẢ NĂNG KHÁNG VI-RÚT GÂY BỆNH ĐỐM TRẮNG CỦA CÁC LOẠI CAO CHIẾT TRÊN MÔ HÌNH TÔM THẺ CHÂN TRẮNG (Litopenaeus vannamei)

Vi-rút gây bệnh đốm trắng (WSSV) là tác nhân lây nhiễm và gây tử vong hàng loạt trên tôm nuôi nước lợ. Nghề nuôi tôm hiện nay thường sử dụng hóa chất và kháng sinh để điều trị và kiểm soát nhiều loại bệnh trong đó có bệnh đốm trắng, việc này gây nhiều trở ngại cho xuất khẩu và tiêu dùng. Có rất nhiều nghiên cứu đã cho thấy tác dụng của nhiều loại thảo dược giúp phòng trị bệnh đốm trắng trên tôm. Trong nghiên cứu này, 15 loại cao chiết thảo dược đã được đánh giá độ độc tính và khảo sát in vitro khả năng kháng WSSV trên mô hình tôm thẻ chân trắng bằng phương pháp tiêm. Kết quả khảo sát độc tính cho thấy, hầu hết các cao chiết là an toàn khi tiêm vào tôm ở nồng độ 0,25 mg/mL, trong đó 5 loại thể hiện độc tính cao, 4 loại thể hiện độc tính trung bình và 6 loại an toàn với tôm. Kết quả đánh giá in vitro cho thấy đưng, dà vôi, ổi, mấm trắng, cỏ mực, đước, cốc trắng và diệp hạ châu có hoạt tính kháng WSSV tốt nhất ở nồng độ khảo sát 0,0025 mg/mL. Những kết quả này tạo tiền đề cho các khảo sát in vivo khả năng kháng WSSV của 8 loại cao chiết thảo dược nhằm tìm ra các loại cây thảo dược tiềm năng trong phòng trị bệnh đốm trắng trên tôm. ABSTRACT White Spot Syndrome Virus (WSSV) is a highly infectious agent and causes mass mortality in farmed shrimp. In shrimp farming nowadays, farmers often use chemicals and antibiotics to treat and control many diseases, including white spot disease, thus resulting in many obstacles for shrimp export and consumption. Many studies have shown the effects of herbs on preventing white spot disease. In this study, 15 types of herbal extracts were evaluated for their toxicity and the in vitro resistance to WSSV in white leg shrimp injection models. The results of the toxicity showed that all the herbal extracts were safe when being injected into shrimp at a concentration of 0.25 mg/mL. Five of the herbs were highly toxic, four had medium toxicity, and six were safe for shrimp. The in vitro WSSV resistance testing showed that there were eight herbal extracts (Rhizophora mucronata, Ceriops tagal, Psidium guajava, Avicennia marina, Eclipta prostrata, Lumnitzera racemosa, Phyllanthus urinaria and Rhizophora apiculata) having the highest activity against WSSV at the concentration of 0.0025 mg/mL. These initial results suggest the in vivo investigations on the resistance to WSSV of these eight herbal extracts to find potential herbal plants for aquaculture use, instead of antibiotics, in the prevention and treatment of white spot disease in shrimp.

Prevalence of Pneumococcal Carriage among Jordanian Infants in the First 6 Months of Age, 2008–2016

Background: Streptococcus pneumoniae is an opportunistic human-adapted pathogen driven by nasopharyngeal carriage. Aims: To find the pneumococcal carriage rate, resistance, serotypes, and coverage of pneumococcal conjugate vaccines (PCVs) among infants in the first six months of age in the period from March 2008 to April 2016. Methods: Nasopharyngeal swabs (NP) were taken from healthy infants from the northern part of Jordan. Swabs were processed for cultivation, identification, resistance testing and serotyping according to standard methods. Results: During the surveillance period, 484 infants of this age group were tested, with a total carriage rate of 56.2%. 96.2% of infants one to two months of age got one PCV7 injection and were 58% carriers at the time of the first injection. At age three to four months, 84.9% had received two injections, with a carriage rate of 54.9% at the time of the second injection. At ages five to six months, 12.5% had received one to three injections, with a carriage rate of 43.8%. Predominant serotypes in all age groups were 19F (12.5%), 6A (11.4%), 11A (8.4%), 19A (7.0%), 6B (6.6%), 23F (5.9%), 15B (5.1%), 15A and 23A (4.0% each). Coverage of PCV7, PCV13 and the future PCV20 among all cases were 30.5%, 50.7% and 70.6%, respectively. The highest coverage rate of 78.6% was noticed in the age group at five to six months with the future PCV20. Antibiotic resistance was the highest in the first age group. Conclusions: Pneumococcal carriage starts from the first month of the infant’s life. The highest coverage was noticed for PCV20, which implies the necessity for inoculation with future vaccines.

Enhancements on Flame Resistance by Inorganic Silicate-Based Intumescent Coating Materials

Flame-retardant coatings have drawn much attention in recent years. In this study, an inorganic sodium silicate-based intumescent flame-resistance coating with an excellent flameproof properties is developed by mainly utilizing sodium silicate as the ceramizable binder, via hydrolysis and self-condensation reaction. Fly ash, metakaoline, and wollastonite behave as supplement cementing materials. Major formulation encompasses the combination of the ammonium polyphosphate and pentaerythritol as the flame-retardant additives, and aluminum hydroxide or expandable graphite as the intumescence-improving filler agents. Expandable graphite was found to play an important role in the eventual performance of flame-resistance testing. The results showed that solid interaction forces can be formed between metakaoline and sodium silicate, resulting in a similar material to geopolymer with excellent physical properties. After high-temperature flame testing, a densely complex protective layer of carbon-char created on top of the robust silicon dioxide networks offers notable flame resistance. An optimal ratio in this inorganic intumescent coating contains sodium silicate—metakaoline (weight ratio = 9:1)—ammonium polyphosphate and pentaerythritol, aluminum hydroxide (3, 3, 10 wt.%)—expandable graphite (1 wt.%), which can create 4.7 times higher expansion ratio compared with neat sodium silicate matrix. The results of flame testing demonstrate only 387.1 °C and 506.3 °C on the back surface of steel substrate after one and three hours flaming (>1000 °C) on the other surface, respectively, which could meet the requirements according to the level of fire rating.