Development of a reporter for prediction of membrane fouling potential and application of nitric oxide for biofouling control

University of Technology Sydney. Faculty of Science.Membrane fouling that results in increases in operational and maintenance costs is a major obstacle to the widespread application of membrane technology. The concentration of assimilable organic carbon (AOC) is directly correlated with the growth of heterotrophic bacteria in water systems. AOC has been widely used as a biofouling indicator for the prediction of biofouling in reverse osmosis (RO) systems. In addition to new methodologies to predict fouling, new membrane cleaning technologies are also being developed. One new cleaning method is the application of nitric oxide (NO), which is a biologically active signaling molecule that has been shown to induce biofilm dispersal at nanomolar concentrations. In this study, potential AOC reporter strains were isolated for use in desalination RO systems. The results show that strains BLS2, CBSW3 and CBSW4 grew on seawater medium, with maximum cell densities of 5.1 x 10⁵, 4.5 x 10⁵ and 7.2 x 10⁵ colony forming unit (CFU) ml⁻¹, respectively. In addition, all three strains were able to metabolise humic substances which are a major component of AOC in seawater, reaching maximum cell numbers of 5.0 x 10⁴ - 2.1 x 10⁵ CFU ml⁻¹. With . A1552 (pUC19-), there was a linear relationship between bioluminescent intensity and glucose concentrations ranging from 0 to 100 μg C L⁻¹, with a coefficient (R²) of 0.9761. The limit detection was 20 μg C L⁻¹. Our findings provide a more rapid AOC assay, which can quickly determine AOC concentrations within 10 min compared to 30 min performed by . MJ1. Pyrosequencing analysis revealed that there was a total of 1,372,739 16S rDNA gene V4 region reads obtained from 9 activated sludge and 10 biofilm samples. RDP Classifier identified 36 phyla, 101 classes and 527 genera of bacteria. The significant changes in relative abundance of the most dominant OTUs associated with the sudden TMP increases demonstrated that species of unclassified , , and unclassified TM7-3 may play important roles in membrane fouling, and that and unclassified TM7-3 may be primary colonisers of the membrane. Unclassified and ( in particular) may be secondary colonisers of the biofilms on the MBR membranes. Treatment of the membranes with 40 μM DETA NONOate led to a reduction of the TMP by 35% compared to 21% obtained by control distilled water backwash (P value < 0.05), indicating that DETA NONOate was effective in delaying TMP increase

Factors affecting calcining temperatures of BZT–BCT ceramics

Piezoelectric ceramic 0.48Ba[Zr0.2Ti0.8]O3 – 0.52[Ba0.7Ca0.3]TiO3 (BZT–BCT) with nanostructure was manufactured with traditional ceramic technology. The nanostructure and the sintering aid reduce the calcining temperature from 1250 to 1170 °C and the sintering temperature from 1450 to 1350 °C. The piezoelectric properties of BZT–BCT at the optimal calcining and sintering temperature are discussed in detail

Long-Term Effectiveness and Drug Survival of Secukinumab in Vietnamese Patients with Psoriasis: Results from a Retrospective ENHANCE Study

Abstract Introduction Psoriasis (PsO), an immune-mediated inflammatory skin disorder, has substantial negative impact on patients’ quality of life. Secukinumab, an approved treatment for moderate-to-severe plaque PsO, has an established long-term efficacy and safety profile. This study aims to provide real-world evidence of long-term effectiveness and retention rate of secukinumab in Vietnamese patients with PsO. Methods This retrospective, observational study collected medical records of adult patients with moderate-to-severe PsO receiving secukinumab treatment from Ho Chi Minh City Hospital of Dermato-Venereology. The primary objective was to evaluate secukinumab effectiveness in PsO as measured by 75% improvement in psoriasis area and severity index (PASI 75) at month 12. Secondary objectives were PASI 90/100, absolute PASI ≤ 3 and ≤ 5, Dermatology Life Quality Index (DLQI), and retention rate over 48 months. Results In total, 232 patients with moderate-to-severe PsO met inclusion criteria; 68.1% were male, with median age and age of onset of 39 and 27.5 years, respectively. Median time from onset of PsO to secukinumab treatment was 120 months, 95.3% were prior biologics/disease-modifying antirheumatic drugs naive and 41.4% received concomitant therapies for PsO; 82.3% had national insurance coverage. At month 12, 93.9% of patients achieved PASI 75 (primary endpoint); 80.2/56.9% achieved PASI 90/100; 91.4 and 84.8% patients achieved absolute PASI ≤ 5 and ≤ 3, respectively. The response was sustained over 48 months, with 91.9%/78.0%/52.0% of patients achieving PASI 75/90/100, 89.5% and 82.1% patients achieving absolute PASI ≤ 5 and ≤ 3, respectively. At month 12, 61.4% of patients achieved DLQI 0/1 which was sustained up to month 48 (69.2%). Secukinumab adherence rate of 84.9% at month 12 dropped to 34.2% at month 48. Patients receiving concomitant therapy and national insurance showed higher adherence rate. Conclusion Secukinumab demonstrated long-term effectiveness in real-world Vietnamese patients with moderate-to-severe PsO, with treatment adherence being higher in patients having concomitant therapies and national insurance

Outbreak of Sexually Transmitted Nongroupable Neisseria meningitidis–Associated Urethritis, Vietnam

We report on an outbreak of nongroupable Neisseria meningitidis–associated urethritis, primarily among men who have sex with men in southern Vietnam. Nearly 50% of N. meningitidis isolates were resistant to ciprofloxacin. This emerging pathogen should be considered in the differential diagnosis and management of urethritis

An observational study of breakthrough SARS-CoV-2 Delta variant infections among vaccinated healthcare workers in Vietnam

Background Data on breakthrough SARS-CoV-2 Delta variant infections in vaccinated individuals are limited. Methods We studied breakthrough infections among Oxford-AstraZeneca vaccinated healthcare workers in an infectious diseases hospital in Vietnam. We collected demographic and clinical data alongside serial PCR testing, measurement of SARS-CoV-2 antibodies, and viral whole-genome sequencing. Findings Between 11th–25th June 2021 (7-8 weeks after the second dose), 69 staff tested positive for SARS-CoV-2. 62 participated in the study. Most were asymptomatic or mildly symptomatic and all recovered. Twenty-two complete-genome sequences were obtained; all were Delta variant and were phylogenetically distinct from contemporary viruses obtained from the community or from hospital patients admitted prior to the outbreak. Viral loads inferred from Ct values were 251 times higher than in cases infected with the original strain in March/April 2020. Median time from diagnosis to negative PCR was 21 days (range 8–33). Neutralizing antibodies (expressed as percentage of inhibition) measured after the second vaccine dose, or at diagnosis, were lower in cases than in uninfected, fully vaccinated controls (median (IQR): 69.4 (50.7-89.1) vs. 91.3 (79.6-94.9), p=0.005 and 59.4 (32.5-73.1) vs. 91.1 (77.3-94.2), p=0.043). There was no correlation between vaccine-induced neutralizing antibody levels and peak viral loads or the development of symptoms. Interpretation Breakthrough Delta variant infections following Oxford-AstraZeneca vaccination may cause asymptomatic or mild disease, but are associated with high viral loads, prolonged PCR positivity and low levels of vaccine-induced neutralizing antibodies. Epidemiological and sequence data suggested ongoing transmission had occurred between fully vaccinated individuals