Energy substrate efficiency during batch cultures of Geotrichum candidum

BACKGROUND: Metabolisation of carbon and nitrogen substrates is a key factor during the ripening process of white soft cheeses but has not previously been examined in terms of energy substrate efficiency. Such work could be useful to improve physiological knowledge concerning Geotrichum candidum, a yeast involved in the neutralisation of curd during ripening. Its behaviour was therefore examined during batch cultures on simple (glutamate) or complex (peptones) substrates as nitrogen and carbon sources and lactate as a second carbon source. RESULTS: In addition to their assimilation as carbon and nitrogen sources, G. candidum used peptides and amino acids as energy sources during growth in preference to lactate. Contrarily, during stationary state, lactate was preferred over peptides and amino acids for carbon dissimilation for energy supply, allowing the avoidance of ammonium production. Indeed, lactate dissimilation theoretically yields 15 adenosine triphosphates (ATPs), while only nine ATPs are theoretically yielded during the dissimilation of an amino acid such as glutamate. CONCLUSION: This behaviour can be considered as an energy‐saving response. Indeed, the use of peptides and amino acids as energy sources in addition to being used as carbon and nitrogen sources during G. candidum growth can be related to its deaminating activity and was in agreement with the better energy efficiency expected from utilisation of the same substrate as both carbon and energy source. Contrarily, the better efficiency of lactate dissimilation led to its use during stationary state instead of peptides and amino acids. Copyright © 2008 Society of Chemical Industry     

Quaternary Structure and Hetero-Oligomerization of Recombinant Human Small Heat Shock Protein HspB7 (cvHsp)

In this study, a reliable and simple method of untagged recombinant human HspB7 preparation was developed. Recombinant HspB7 is presented in two oligomeric forms with an apparent molecular weight of 36 kDa (probably dimers) and oligomers with an apparent molecular weight of more than 600 kDa. By using hydrophobic and size-exclusion chromatography, we succeeded in preparation of HspB7 dimers. Mild oxidation promoted the formation of large oligomers, whereas the modification of Cys 126 by iodoacetamide prevented it. The deletion of the first 13 residues or deletion of the polySer motif (residues 17–29) also prevented the formation of large oligomers of HspB7. Cys-mutants of HspB6 and HspB8 containing a single-Cys residue in the central part of the β7 strand in a position homologous to that of Cys137 in HspB1 can be crosslinked to the wild-type HspB7 through a disulfide bond. Immobilized on monoclonal antibodies, the wild-type HspB6 interacted with the wild-type HspB7. We suppose that formation of heterodimers of HspB7 with HspB6 and HspB8 may be important for the functional activity of these small heat shock proteins.     

Real-time air monitoring of occupational exposures to particulate matter among hairdressers in Maryland: A pilot study

Hairdressers are exposed to particulate matter (PM), a known air pollutant linked to adverse health effects. Still, studies on occupational PM exposures in hair salons are sparse. We characterized indoor air PM concentrations in three salons primarily serving an African/African American (AA) clientele, and three Dominican salons primarily serving a Latino clientele. We also assessed the performance of low-cost sensors (uRAD, Flow, AirVisual) by comparing them to high-end sensors (DustTrak) to conduct air monitoring in each salon over 3 days to quantify work shift concentrations of PM_2.5, respirable PM (RPM), and PM₁₀. We observed high spatial and temporal variability in 30-min time-weighted average (TWA) RPM concentrations (0.18–5518 μg/m³). Readings for the uRAD and AirVisual sensors were highly correlated with the DustTrak (R² = 0.90–0.99). RPM 8-hour TWAs ranged from 18 to 383 µg/m³ for AA salons, and 9–2115 µg/m³ for Dominican salons. Upper 95th percentiles of daily RPM exposures ranged from 439 to 2669 µg/m³. The overall range of 30-min TWA PM_2.5 and PM₁₀ concentrations was 0.13–5497 and 0.36-,541 μg/m³, respectively. Findings suggest that hairdressers could be overexposed to RPM during an 8-hour shift. Additional comprehensive monitoring studies are warranted to further characterize temporal and spatial variability of PM exposures in this understudied occupational population.     

Identification of Phenylpyrazolone Dimers as a New Class of Anti-Trypanosoma cruzi Agents

Chagas disease is becoming a worldwide problem; it is currently estimated that over six million people are infected. The two drugs in current use, benznidazole and nifurtimox, require long treatment regimens, show limited efficacy in the chronic phase of infection, and are known to cause adverse effects. Phenotypic screening of an in-house library led to the identification of 2,2′-methylenebis(5-(4-bromophenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one), a phenyldihydropyrazolone dimer, which shows an in vitro pIC₅₀ value of 5.4 against Trypanosoma cruzi. Initial optimization was done by varying substituents of the phenyl ring, after which attempts were made to replace the phenyl ring. Finally, the linker between the dimer units was varied, ultimately leading to 2,2′-methylenebis(5-(3-bromo-4-methoxyphenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one (NPD-0228) as the most potent analogue. NPD-0228 has an in vitro pIC₅₀ value of 6.4 against intracellular amastigotes of T. cruzi and no apparent toxicity against the human MRC-5 cell line and murine cardiac cells.     

Switchable Supercapacitors with Transistor‐Like Gating Characteristics (G‐Cap)

A novel three‐electrode electrolyte supercapacitor (electric double‐layer capacitor [EDLC]) architecture in which a symmetrical interdigital “working” two‐electrode micro‐supercapacitor array (W‐Cap) is paired with a third “gate” electrode that reversibly depletes/injects electrolyte ions into the system controlling the “working” capacity effectively is described. All three electrodes are based on precursor‐derived nanoporous carbons with well‐defined specific surface area (735 m² g^?1). The interdigitated architecture of the W‐Cap is precisely manufactured using 3D printing. The W‐Cap operating with a proton conducting PVA/H₂SO₄‐hydrogel electrolyte and high capacitance (6.9 mF cm^?2) can be repeatedly switched “on” and “off”. By applying a low DC bias potential (?0.5 V) at the gate electrode, the AC electroadsorption in the coupled interdigital nanoporous carbon electrodes of the W‐Cap is effectively suppressed leading to a stark capacity drop by two orders of magnitude from an “on” to an “off” state. The switchable micro‐supercapacitor is the first of its kind. This general concept is suitable for implementing a broad range of nanoporous materials and advanced electrolytes expanding its functions and applications in future. The integration of intelligent functions into EDLC devices has extensive implications for diverse areas such as capacitive energy management, microelectronics, iontronics, and neuromodulation.     

Doping and Switchable Photovoltaic Effect in Lead‐Free Perovskites Enabled by Metal Cation Transmutation

Creating defect tolerant lead‐free halide perovskites is the major challenge for development of high‐performance photovoltaics with nontoxic absorbers. Few compounds of Sn, Sb, or Bi possess ns² electronic configuration similar to lead, but their poor photovoltaic performances inspire us to evaluate other factors influencing defect tolerance properties. The effect of heavy metal cation (Bi) transmutation and ionic migration on the defects and carrier properties in a 2D layered perovskite (NH₄)₃(Sb_(1?x)Bi_x)₂I₉ system is investigated. It is shown, for the first time, the possibility of engineering the carriers in halide perovskites via metal cation transmutation to successfully form intrinsic p‐ and n‐type materials. It is also shown that this material possesses a direct–indirect bandgap enabling high absorption coefficient, extended carrier lifetimes >100 ns, and low trap densities similar to lead halide perovskites. This study also demonstrates the possibility of electrical poling to induce switchable photovoltaic effect without additional electron and hole transport layers.     

Blockchain Assisted Intrusion Detection System Using Differential Flower Pollination Model

Cyberattacks are developing gradually sophisticated, requiring effective intrusion detection systems (IDSs) for monitoring computer resources and creating reports on anomalous or suspicious actions. With the popularity of Internet of Things (IoT) technology, the security of IoT networks is developing a vital problem. Because of the huge number and varied kinds of IoT devices, it can be challenging task for protecting the IoT framework utilizing a typical IDS. The typical IDSs have their restrictions once executed to IoT networks because of resource constraints and complexity. Therefore, this paper presents a new Blockchain Assisted Intrusion Detection System using Differential Flower Pollination with Deep Learning (BAIDS-DFPDL) model in IoT Environment. The presented BAIDS-DFPDL model mainly focuses on the identification and classification of intrusions in the IoT environment. To accomplish this, the presented BAIDS-DFPDL model follows blockchain (BC) technology for effective and secure data transmission among the agents. Besides, the presented BAIDS-DFPDL model designs Differential Flower Pollination based feature selection (DFPFS) technique to elect features. Finally, sailfish optimization (SFO) with Restricted Boltzmann Machine (RBM) model is applied for effectual recognition of intrusions. The simulation results on benchmark dataset exhibit the enhanced performance of the BAIDS-DFPDL model over other models on the recognition of intrusions.