International Journal of Mathematical Combinatorics, vol. 1/2017

The International J.Mathematical Combinatorics (ISSN 1937-1055) is a fully refereed international journal, sponsored by the MADIS of Chinese Academy of Sciences and published in USA quarterly comprising 110-160 pages approx. per volume, which publishes original researchpapers and survey articles in all aspects of Smarandache multi-spaces, Smarandache geometries, mathematical combinatorics, non-euclidean geometry and topology and their applications to other sciences

International Journal of Mathematical Combinatorics, vol. 4/2012

The International J.Mathematical Combinatorics (ISSN 1937-1055) is a fully refereed international journal, sponsored by the MADIS of Chinese Academy of Sciences and published in USA quarterly comprising 100-150 pages approx. per volume, which publishes original researchpapers and survey articles in all aspects of Smarandache multi-spaces, Smarandache geometries, mathematical combinatorics, non-euclidean geometry and topology and their applications to other sciences

Table_1_YOLOv5s-gnConv: detecting personal protective equipment for workers at height.DOCX

IntroductionFalls from height (FFH) accidents can devastate families and individuals. Currently, the best way to prevent falls from heights is to wear personal protective equipment (PPE). However, traditional manual checking methods for safety hazards are inefficient and difficult to detect and eliminate potential risks.MethodsTo better detect whether a person working at height is wearing PPE or not, this paper first applies field research and Python crawling techniques to create a dataset of people working at height, extends the dataset to 10,000 images through data enhancement (brightness, rotation, blurring, and Moica), and categorizes the dataset into a training set, a validation set, and a test set according to the ratio of 7:2:1. In this study, three improved YOLOv5s models are proposed for detecting PPE in construction sites with many open-air operations, complex construction scenarios, and frequent personnel changes. Among them, YOLOv5s-gnconv is wholly based on the convolutional structure, which achieves effective modeling of higher-order spatial interactions through gated convolution (gnConv) and cyclic design, improves the performance of the algorithm, and increases the expressiveness of the model while reducing the network parameters.ResultsExperimental results show that YOLOv5s-gnconv outperforms the official model YOLOv5s by 5.01%, 4.72%, and 4.26% in precision, recall, and mAP_0.5, respectively. It better ensures the safety of workers working at height.DiscussionTo deploy the YOLOv5s-gnConv model in a construction site environment and to effectively monitor and manage the safety of workers at height, we also discuss the impacts and potential limitations of lighting conditions, camera angles, and worker movement patterns.</p

Ce Single-Atom Incorporation Enhances the Oxygen Evolution Reaction of Co₃O₄ in Acid

Oxygen evolution reaction (OER) plays an important role in energy conversion processes such as water electrolysis and metal–air batteries. At present, finding a high-performance and low-cost catalyst for the OER in acidic media remains a great challenge. It is therefore important to develop efficient, robust, and inexpensive electrocatalysts by replacing noble metal-based catalysts with transition-metal electrocatalysts. Herein, we propose a facile method for incorporating Ce-metal single atoms into Co3O4 nanosheets to boost their OER activity and stability. Owing to the enhanced charge transfer and improved electronic structure resulting from Ce incorporation, the obtained Ce single-atom-doped Co3O4 nanosheet exhibits greatly enhanced OER performance. It achieves a 10 mA cm–2 current density under a low overpotential of 348 mV in a 0.5 M H2SO4 solution with excellent stability, outperforming the state-of-the-art non-noble electrocatalysts recently reported in acid

Reversible Unfolding and Folding of the Metalloprotein Ferredoxin Revealed by Single-Molecule Atomic Force Microscopy

Plant type [2Fe-2S] ferredoxins function primarily as electron transfer proteins in photosynthesis. Studying the unfolding–folding of ferredoxins in vitro is challenging, because the unfolding of ferredoxin is often irreversible due to the loss or disintegration of the iron–sulfur cluster. Additionally, the in vivo folding of holo-ferredoxin requires ferredoxin biogenesis proteins. Here, we employed atomic force microscopy-based single-molecule force microscopy and protein engineering techniques to directly study the mechanical unfolding and refolding of a plant type [2Fe-2S] ferredoxin from cyanobacteria Anabaena. Our results indicate that upon stretching, ferredoxin unfolds in a three-state mechanism. The first step is the unfolding of the protein sequence that is outside and not sequestered by the [2Fe-2S] center, and the second one relates to the force-induced rupture of the [2Fe-2S] metal center and subsequent unraveling of the protein structure shielded by the [2Fe-2S] center. During repeated stretching and relaxation of a single polyprotein, we observed that the completely unfolded ferredoxin can refold to its native holo-form with a fully reconstituted [2Fe-2S] center. These results demonstrate that the unfolding–refolding of individual ferredoxin is reversible at the single-molecule level, enabling new avenues of studying both folding–unfolding mechanisms, as well as the reactivity of the metal center of metalloproteins in vitro

The circadian rhythm (hours±SEM) and the statistical results compared with the control group.

The circadian rhythm (hours±SEM) and the statistical results compared with the control group.</p

This file contains all of the spectra data of the fluorescent lamp and LEDs.

(XLSX)</p

Growth results of the samples.

The samples were placed on the starting points on the far-left side of the Race Tube. It grew up from the left side to the right side to the end of the Race Tube. The orange sections in the picture mark the conidiations. The black spots on the Race Tubes were the growth length of the sample, which were marked every 12 hours. There were three different types of growth results, and the arrows indicated a black spot at 24 hours, 72 hours and 120 hours. Type 1 (yellow arrows) showed that a 24 hours period of circadian rhythm, the three arrows were always in the middle of conidiation. Type 2 (white arrows) indicated that a 22.3 hours per period, the second arrow approached conidiation, and the third arrow was included in conidiation. Type 3 (red arrows) was around 21.7 hours per period, the second arrow was included in conidiation, the third arrow exceeded conidiation.</p

The spectra of the fluorescent lamp and LEDs.

(a) The spectrum of the fluorescent lamp. (b) The spectrum of the LEDs. Left to right: violet (FWHM = 15.7 nm), blue (FWHM = 23.7 nm), green (FWHM = 33.9 nm) and yellow (FWHM = 20.5 nm) LEDs. We replaced the fluorescent lamp with the monochromatic LED for the light intervention experiment.</p