Donning and doffing of personal protective equipment for health care workers in a tertiary hospital in China: A simulation study.

The application and removal of personal protective equipment (PPE) by health care workers (HCWs) is pivotal to their health and safety and the comprehensive efficacy of hospital infection control measures. This investigation was orchestrated to elucidate the challenges that HCWs may encounter during the donning and doffing of PPE. A total of 110 participants from a tertiary hospital in China were engaged. The study employed fluorescent markers to mimic the exposure of HCWs to tainted body fluids, quantified the contamination outcomes, and evaluated adherence to procedures for donning and doffing. Factors including gender, educational background, and the timing of the most recent instruction on PPE donning and doffing were found to influence the occurrence of contamination points (p < 0.05). No significant differences were identified in contamination frequency when assessing age, body mass index (BMI), occupation, educational background, positional title, working tenure, and experience in managing respiratory infectious diseases (p > 0.05). Predominant contamination sites for fluorescent marker residue included the shoulder (32.73%), neck (21.82%), forearm (16.36%), chest (12.73%), and abdomen (11.82%), with the shoulder being the most contaminated body part. A majority of HCWs exhibited susceptibility to errors during the removal of protective clothing, boot covers, and gloves. The contamination frequency was observed to be correlated with the timing of the last PPE training, educational background, and gender. In acknowledging the intricacy of PPE removal and the deficiencies in HCWs' removal techniques, there emerges a perpetual necessity to refine training methodologies and perpetuate regular PPE instruction.

The Method of Creel Positioning Based on Monocular Vision.

Automatic replacement of bobbins on the frame is one of the core problems that must be solved in the textile industry. In the process of changing the bobbin, it is faced with problems such as the position offset of the bobbin, the loosening and deformation of the bobbin, which will lead to the failure of replacing the bobbin. Therefore, it is necessary to initialize the creel coordinates regularly, also considering the labor intensity and poor reliability of manual positioning. This paper proposes an automatic creel positioning method based on monocular vision. Firstly, the industrial camera was installed on the drum changing manipulator controlled by the truss system, and each yarn frame in the yarn area was inspected. Secondly, the end face image of the creel was collected at a reasonable distance, and the collected images were transmitted to the computer in real time through the Ethernet bus. Thirdly, the center coordinates (x, y) and radius r of the creel were marked by the improved Hough circle detection algorithm. Finally, the coordinate deviation of the creel was calculated and transmitted to the system controller to realize deviation correction. Before the test, the creel positioning markers were specially designed and the camera was calibrated. Thus, the influence of image complex background, creel end roughness, reflection and other factors can be reduced, and the image processing speed and positioning accuracy can be improved. The results show that the positioning effect of this method is fine when the distance between the center of the camera lens and the center of the end face of the creel is 170~190 mm. Moreover, when the distance is 190 mm, the positioning effect is the best, with an average error of only 0.51 mm. In addition, the deviation between the center coordinate and the radius of the end face of the marker is also very small, which is better than the requirements of bobbin yarn changing accuracy.

Genome Mining and Metabolic Profiling Uncover Polycyclic Tetramate Macrolactams from Streptomyces koyangensis SCSIO 5802.

We have previously shown deep-sea-derived Streptomyces koyangensis SCSIO 5802 to produce two types of active secondary metabolites, abyssomicins and candicidins. Here, we report the complete genome sequence of S. koyangensis SCSIO 5802 employing bioinformatics to highlight its potential to produce at least 21 categories of natural products. In order to mine novel natural products, the production of two polycyclic tetramate macrolactams (PTMs), the known 10-epi-HSAF (1) and a new compound, koyanamide A (2), was stimulated via inactivation of the abyssomicin and candicidin biosynthetic machineries. Detailed bioinformatics analyses revealed a PKS/NRPS gene cluster, containing 6 open reading frames (ORFs) and spanning ~16 kb of contiguous genomic DNA, as the putative PTM biosynthetic gene cluster (BGC) (termed herein sko). We furthermore demonstrate, via gene disruption experiments, that the sko cluster encodes the biosynthesis of 10-epi-HSAF and koyanamide A. Finally, we propose a plausible biosynthetic pathway to 10-epi-HSAF and koyanamide A. In total, this study demonstrates an effective approach to cryptic BGC activation enabling the discovery of new bioactive metabolites; genome mining and metabolic profiling methods play key roles in this strategy.

Characterization and heterologous expression of the neoabyssomicin/abyssomicin biosynthetic gene cluster from Streptomyces koyangensis SCSIO 5802.

BACKGROUND: The deep-sea-derived microbe Streptomyces koyangensis SCSIO 5802 produces neoabyssomicins A-B (1-2) and abyssomicins 2 (3) and 4 (4). Neoabyssomicin A (1) augments human immunodeficiency virus-1 (HIV-1) replication whereas abyssomicin 2 (3) selectively reactivates latent HIV and is also active against Gram-positive pathogens including methicillin-resistant Staphylococcus aureus (MRSA). Structurally, neoabyssomicins A-B constitute a new subtype within the abyssomicin family and feature unique structural traits characteristic of extremely interesting biosynthetic transformations. RESULTS: In this work, the biosynthetic gene cluster (BGC) for the neoabyssomicins and abyssomicins, composed of 28 opening reading frames, was identified in S. koyangensis SCSIO 5802, and its role in neoabyssomicin/abyssomicin biosynthesis was confirmed via gene inactivation and heterologous expression experiments. Bioinformatics and genomics analyses enabled us to propose a biosynthetic pathway for neoabyssomicin/abyssomicin biosynthesis. Similarly, a protective export system by which both types of compounds are secreted from the S. koyangensis producer was identified, as was a four-component ABC transporter-based import system central to neoabyssomicin/abyssomicin biosynthesis. Furthermore, two regulatory genes, abmI and abmH, were unambiguously shown to be positive regulators of neoabyssomicin/abyssomicin biosynthesis. Consistent with their roles as positive regulatory genes, the overexpression of abmI and abmH (independent of each other) was shown to improve neoabyssomicin/abyssomicin titers. CONCLUSIONS: These studies provide new insight into the biosynthesis of the abyssomicin class of natural products, and highlight important exploitable features of its BGC for future efforts. Elucidation of the neoabyssomicin/abyssomicin BGC now enables combinatorial biosynthetic initiatives aimed at improving both the titers and pharmaceutical properties of these important natural products-based drug leads.

Lightweight bobbin yarn detection model for auto-coner with yarn bank.

The automated replacement of empty tubes in the yarn bank is a critical step in the process of automatic winding machines with yarn banks, as the real-time detection of depleted yarn on spools and accurate positioning of empty tubes directly impact the production efficiency of winding machines. Addressing the shortcomings of traditional methods, such as poor adaptability and low sensitivity in optical and visual tube detection, and aiming to reduce the computational and detection time costs introduced by neural networks, this paper proposes a lightweight yarn spool detection model based on YOLOv8. The model utilizes Darknet-53 as the backbone network, and due to the dense spatial distribution of yarn spool targets, it incorporates large selective kernel units to enhance the recognition and positioning of dense targets. To address the issue of excessive focus on local features by convolutional neural networks, a bi-level routing attention mechanism is introduced to capture long-distance dependencies dynamically. Furthermore, to balance accuracy and detection speed, a FasterNeck is constructed as the neck network, replacing the original convolutional blocks with Ghost convolutions and integrating with FasterNet. This design minimizes the sacrifice of detection accuracy while achieving a significant improvement in inference speed. Lastly, the model employs weighted IoU with a dynamic focusing mechanism as the bounding box loss function. Experimental results on a custom yarn spool dataset demonstrate a notable improvement over the baseline model, with a high-confidence mAP of 94.2% and a compact weight size of only 4.9 MB. The detection speed reaches 223FPS, meeting the requirements for industrial deployment and real-time detection.

Nonspecific Heme-Binding Cyclase, AbmU, Catalyzes [4 + 2] Cycloaddition during Neoabyssomicin Biosynthesis.

Diels-Alder (DA) [4 + 2]-cycloaddition reactions rank among the most powerful transformations in synthetic organic chemistry; biosynthetic examples, however, are few and far between. We report here a heme-binding cyclase, AbmU, that catalyzes an essential [4 + 2] cycloaddition during neoabyssomicin scaffold assembly. In vivo genetic and in vitro biochemical analyses strongly suggest that AbmU catalyzes an intramolecular and stereoselective [4 + 2] cycloaddition to form a spirotetronate skeleton from an acyclic substrate featuring both a terminal 1,3-diene and an exo-methylene group. Biochemical assays and X-ray diffraction analyses reveal that AbmU binds nonspecifically to a heme b cofactor and that this association does not play a catalytic role in AbmU catalysis. A detailed study of the AbmU crystal structure reveals a unique mode of substrate binding and reaction catalysis; His160 forms a H-bond with the C-1 carbonyl O-atom of the acyclic substrate, and the imidazole of the same amino acid directs the tetronate moiety of acyclic substrate toward the terminal Δ10,11, Δ12,13-diene moiety, thereby facilitating intramolecular DA chemistry. Our findings expand upon what is known about mechanistic diversities available to biosynthetic [4 + 2] cyclases and help to lay the foundation for the use of AbmU in possible industrial applications.

Biocatalysis of ursolic acid by the fungus Gliocladium roseum CGMCC 3.3657 and resulting anti-HCV activity.

Biocatalysis of ursolic acid (UA 1) by Gliocladium roseum CGMCC 3.3657 was investigated. Baeyer-Villiger oxidation was found to occur during the reaction. Four metabolites were isolated from the cultures and their structures were identified as 21-oxo,A-homo-3a-oxa-urs-12-en-3-one-28-oic acid (2), 21-oxo-3,4-seco-ursan-4(23),12-dien-3,28-dioic acid (3), 21ß-hydroxyl-A-homo-3a-oxa-urs-12-en-3-one-28-oic acid (4) and 21ß-hydroxyl-3,4-seco-ursan-4(23),12-dien-3,28-dioic acid (5), based on their NMR and MS spectral data. All of the four metabolites were new and their anti-HCV activity was tested. Their biotransformation pathway was also proposed.

AbmV Catalyzes Tandem Ether Installation and Hydroxylation during Neoabyssomicin/Abyssomicin Biosynthesis.

Members of the abyssomicin class of natural products are characterized by a novel vinylic bridged ether ring. In this study, in vivo gene inactivation, structure elucidation of the accumulated intermediate abyssomicin 6, and in vitro enzyme assays enabled the identification of a cytochrome P450 enzyme, AbmV. AbmV carries out domino reactions involving bridged ether installation and C-11 hydroxylation during the biosynthesis of neoabyssomicins/abyssomicins in S. koyangensis SCSIO 5802.