Designing a novel heterostructure AgInS₂@MIL-101(Cr) photocatalyst from PET plastic waste for tetracycline degradation

Semiconductor-containing porous materials with a well-defined structure could be unique scaffolds for carrying out selective organic transformations driven by visible light. We herein introduce for the first time a heterostructure of silver indium sulfide (AgInS(2)) ternary chalcogenide and a highly porous MIL-101(Cr) metal–organic framework (MOF) synthesised from polyethylene terephthalate plastic waste. Our results demonstrate that AgInS(2) nanoparticles were uniformly attached to each lattice plane of the octahedral MIL-101(Cr) structure, resulting in a nanocomposite with a high distribution of semiconductors in a porous media. We also demonstrate that the nanocomposite with up to 40% of AgInS(2) doping exhibited excellent catalytic activity for tetracycline degradation under visible light irradiation (∼99% tetracycline degraded after 4 h) and predominantly maintained its performance after five cycles. These results could promote a new material circularity pathway to develop new semiconductors that can be used to protect water from further pollution

Oxidation of bacillithiol during killing of Staphylococcus aureus USA300 inside neutrophil phagosomes

Targeting immune evasion tactics of pathogenic bacteria may hold the key to treating recalcitrant bacterial infections. Staphylococcus aureus produces bacillithiol (BSH), its major low-molecular-weight thiol, which is thought to protect this opportunistic human pathogen against the bombardment of oxidants inside neutrophil phagosomes. Here, we show that BSH was oxidized when human neutrophils phagocytosed S. aureus, but provided limited protection to the bacteria. We used mass spectrometry to measure the oxidation of BSH upon exposure of S. aureus USA300 to either a bolus of hypochlorous acid (HOCl) or a flux generated by the neutrophil enzyme myeloperoxidase. Oxidation of BSH and loss of bacterial viability were strongly correlated (r = 0.99, p < 0.001). BSH was fully oxidized after exposure of S. aureus to lethal doses of HOCl. However, there was no relationship between the initial BSH levels and the dose of HOCl required for bacterial killing. In contrast to the HOCl systems, only 50% of total BSH was oxidized when neutrophils killed the majority of phagocytosed bacteria. Oxidation of BSH was decreased upon inhibition of myeloperoxidase, implicating HOCl in phagosomal BSH oxidation. A BSH-deficient S. aureus USA300 mutant was slightly more susceptible to treatment with either HOCl or ammonia chloramine, or to killing within neutrophil phagosomes. Collectively, our data show that myeloperoxidase-derived oxidants react with S. aureus inside neutrophil phagosomes, leading to partial BSH oxidation, and contribute to bacterial killing. However, BSH offers only limited protection against the neutrophil's multifaceted killing mechanisms

Commensurate and Incommensurate Vortex States in Superconductors with Periodic Pinning Arrays

As a function of applied field, we find a rich variety of ordered and partially-ordered vortex lattice configurations in systems with square or triangular arrays of pinning sites. We present formulas that predict the matching fields at which commensurate vortex configurations occur and the vortex lattice orientation with respect to the pinning lattice. Our results are in excellent agreement with recent imaging experiments on square pinning arrays [K. Harada et al., Science 274, 1167 (1996)].Comment: 9 pages, 3 figures. Accepted to Physical Review

Vanishing Twist near Focus-Focus Points

We show that near a focus-focus point in a Liouville integrable Hamiltonian system with two degrees of freedom lines of locally constant rotation number in the image of the energy-momentum map are spirals determined by the eigenvalue of the equilibrium. From this representation of the rotation number we derive that the twist condition for the isoenergetic KAM condition vanishes on a curve in the image of the energy-momentum map that is transversal to the line of constant energy. In contrast to this we also show that the frequency map is non-degenerate for every point in a neighborhood of a focus-focus point.Comment: 13 page

Point-of-care C-reactive protein testing to reduce inappropriate use of antibiotics for non-severe acute respiratory infections in Vietnamese primary health care: a randomised controlled trial

Background Inappropriate antibiotic use for acute respiratory tract infections is common in primary health care, but distinguishing serious from self-limiting infections is diffi cult, particularly in low-resource settings. We assessed whether C-reactive protein point-of-care testing can safely reduce antibiotic use in patients with non-severe acute respiratory tract infections in Vietnam. Method We did a multicentre open-label randomised controlled trial in ten primary health-care centres in northern Vietnam. Patients aged 1–65 years with at least one focal and one systemic symptom of acute respiratory tract infection were assigned 1:1 to receive either C-reactive protein point-of-care testing or routine care, following which antibiotic prescribing decisions were made. Patients with severe acute respiratory tract infection were excluded. Enrolled patients were reassessed on day 3, 4, or 5, and on day 14 a structured telephone interview was done blind to the intervention. Randomised assignments were concealed from prescribers and patients but not masked as the test result was used to assist treatment decisions. The primary outcome was antibiotic use within 14 days of follow-up. All analyses were prespecifi ed in the protocol and the statistical analysis plan. All analyses were done on the intention-totreat population and the analysis of the primary endpoint was repeated in the per-protocol population. This trial is registered under number NCT01918579. Findings Between March 17, 2014, and July 3, 2015, 2037 patients (1028 children and 1009 adults) were enrolled and randomised. One adult patient withdrew immediately after randomisation. 1017 patients were assigned to receive C-reactive protein point-of-care testing, and 1019 patients were assigned to receive routine care. 115 patients in the C-reactive protein point-of-care group and 72 patients in the routine care group were excluded in the intention-to-treat analysis due to missing primary endpoint. The number of patients who used antibiotics within 14 days was 581 (64%) of 902 patients in the C-reactive protein group versus 738 (78%) of 947 patients in the control group (odds ratio [OR] 0·49, 95% CI 0·40–0·61; p<0·0001). Highly signifi cant diff erences were seen in both children and adults, with substantial heterogeneity of the intervention eff ect across the 10 sites (I²=84%, 95% CI 66–96). 140 patients in the C-reactive protein group and 137 patients in the routine care group missed the urine test on day 3, 4, or 5. Antibiotic activity in urine on day 3, 4, or 5 was found in 267 (30%) of 877 patients in the C-reactive protein group versus 314 (36%) of 882 patients in the routine treatment group (OR 0·78, 95% CI 0·63–0·95; p=0·015). Time to resolution of symptoms was similar in both groups. Adverse events were rare, with no deaths and a total of 14 hospital admissions (six in the C-reactive protein group and eight in the control group). Interpretation C-reactive protein point-of-care testing reduced antibiotic use for non-severe acute respiratory tract infection without compromising patients’ recovery in primary health care in Vietnam. Health-care providers might have become familiar with the clinical picture of low C-reactive protein, leading to reduction in antibiotic prescribing in both groups, but this would have led to a reduction in observed eff ect, rather than overestimation. Qualitative analysis is needed to address diff erences in context in order to implement this strategy to improve rational antibiotic use for patients with acute respiratory infection in low-income and middle-income countries

Imaging spontaneous currents in superconducting arrays of pi-junctions

Superconductors separated by a thin tunneling barrier exhibit the Josephson effect that allows charge transport at zero voltage, typically with no phase shift between the superconductors in the lowest energy state. Recently, Josephson junctions with ground state phase shifts of pi proposed by theory three decades ago have been demonstrated. In superconducting loops, pi-junctions cause spontaneous circulation of persistent currents in zero magnetic field, analogous to spin-1/2 systems. Here we image the spontaneous zero-field currents in superconducting networks of temperature-controlled pi-junctions with weakly ferromagnetic barriers using a scanning SQUID microscope. We find an onset of spontaneous supercurrents at the 0-pi transition temperature of the junctions Tpi = 3 K. We image the currents in non-uniformly frustrated arrays consisting of cells with even and odd numbers of pi-junctions. Such arrays are attractive model systems for studying the exotic phases of the 2D XY-model and achieving scalable adiabatic quantum computers.Comment: Pre-referee version. Accepted to Nature Physic

Redescription of three caligid species of the genus Caligus Müller, 1785 (Copepoda: Caligidae), parasites of marine fish Decapterus sp. (Perciformes: Carangidae) from Tonkin gulf, Vietnam

So far, parasitic copepods belonging to the family Caligidae on marine fishes in Vietnam have been poorly studied. At present, 250 copepods species belong to the genus Caligus have been registrated in the world, including 54 species recognized in waters of the South East Asia region and 11 species recorded from Vietnam. Based on the specimens of parasite copepods found on the marine fish Decapterus sp. which were collected by scientific researchers of TINRO, Vladivostok Russia from Tonkin gulf, Vietnam in 1960-1961, a re-description of three species of the genus Caligus, viz. Caligus confusus Pillai, 1961, C. constrictus Heller, 1865 and C. robustus Bassett-Smith, 1898 is given. The hosts, distribution and key to the eleven Caligus species for Vietnamese fauna are also provided herein

Heterologous expression and characterization of a MoAA16 polysaccharide monooxygenase from the rice blast fungus Magnaporthe oryzae

Background: Cellulose is an organic carbon source that can be used as a sustainable alternative for energy, materials, and chemicals. However, the substantial challenge of converting it into soluble sugars remains a major obstacle in its use as a biofuel and chemical feedstock. A new class of enzymes knowns as copper-dependent polysaccharide monooxygenases (PMOs) or lytic polysaccharide monooxygenases (LPMOs) can break down polysaccharides such as cellulose, chitin, and starch through oxidation. This process enhances the efficiency of cellulose degradation by cellulase. Results: The genome of the fungus Magnaporthe oryzae, the causal agent of rice blast disease, contains the MGG_00245 gene, which encodes a putative PMO referred to as MoAA16. MoAA16 has been found to be highly expressed in planta during the early stages of fungal infection. The gene was optimized for heterologous expression in Pichia pastoris, and its oxidative cleavage activity on cellulose was characterized by analyzing soluble oligosaccharide products using highperformance anion exchange chromatography (HPAEC-PAD). The reaction catalyzed by MoAA16 requires 2 electrons from an electron donor, such as ascorbic acid, and aerobic conditions. It primarily produces Glc1 to Glc4 oligosaccharides, as well as oxidized cellobionic and cellotrionic acids. MoAA16 has been observed to enhance cellulase hydrolysis on phosphoric acid swollen cellulose (PASC) substrate, resulting in the production of more monosaccharide products. Conclusions: Our findings reveal the successful heterologous expression of MoAA16 in P. pastoris and its cellulose-active PMO properties. These results highlight the potential of MoAA16 as a promising candidate for applications in biofuel production and chemical synthesis. How to cite: Nguyen HM, Le LQ, Sella L, et al. Heterologous expression and characterization of a MoAA16 polysaccharide monooxygenase from the rice blast fungus Magnaporthe oryzae. Electron J Biotechnol 2023. https://doi.org/10.1016/j.ejbt.2023.06.002

Industrial brewing yeast engineered for the production of primary flavor determinants in hopped beer

Production of aromatic monoterpene molecules in hop flowers is affected by genetic, environmental, and processing factors. Here, the authors engineer brewer’s yeast for the production of linalool and geraniol, and show pilot-scale beer produced by engineered strains reconstitutes some qualities of hop flavor