Current Chinese Science - Volume 3, Issue 1, 2023

Background: Breast cancer is the second leading cause of death in females worldwide. Mammograms are useful in early cancer diagnosis as well when the patient can sense symptoms or they become observable. Inspection of mammograms in search of breast tumors is a difficult task that radiologists must carry out frequently. Objective: This paper provides a summary of possible strategies used in automated systems for a mammogram, especially focusing on segmentation techniques used for cancer localization in mammograms. Methods: This article is intended to present a brief overview for nonexperts and beginners in this field. It starts with an overview of the mammograms, public and private available datasets, image processing techniques used for a mammogram and cancer classification followed by cancer segmentation using the machine and deep learning techniques. Conclusion: The approaches used in these stages are summarized, and their advantages and disadvantages with possible future research directions are discussed. In the future, we will train a model of medical images that can be used for transfer learning in mammograms.

Aims: Finding a simple, energy-saving and low-cost synthesis method to process gallium oxide nanowires by CVD for solar-blind detector. Background: Due to a bandgap of 4.5 ~ 4.9 eV and a high breakdown field strength of 8 MV/cm, gallium oxide (Ga2O3) has great application prospects in solar blind ultraviolet detection and highpower devices. Notably, Ga2O3 NWs are currently the key research objects of solar-blind UV detection materials because of the characteristics of efficient photocarrier separation and collection, and the bandgap width perfectly matches the energy of deep ultraviolet photons. Objective: To find a simple method to synthesize Ga2O3 nanowire with smooth surface and uniform diameter, and the prepared single gallium oxide nanowire UV detector has high photoelectric conversion efficiency. Methods: Ga2O3NWs are prepared on the SiO2/Si substrate by chemical vapor deposition (CVD) approach at low reaction temperature with gold particles serving as the catalyst and gallium arsenide (GaAs) as a gallium source. Results: X-ray diffraction and Raman spectroscopy characterization indicate the crystal structure of NWs is β-Ga2O3, and scanning electron microscope (SEM) characterization proves that the NWs have a uniform diameter and smooth surface. Moreover, the high-resolution transmission electron microscopy (HRTEM) characterization shows that the material had high crystal quality. Moreover, the photoconductive solar-blind UV detector with a single Ga2O3 NW is prepared, showing the excellent performance of the high responsivity and external quantum efficiency. Conclusion: The effects of growth temperature and the size of gold catalyst on the morphology of β-Ga2O3 NWs have been investigated. The results show that with the reaction temperature is 625 °C and the diameter of Au catalyst is about 30~50 nm, it is more conducive to the formation of NMs with crystal structure, smooth surface and uniform diameter. The performance of the solar-blind UV photodetector shows that the device has higher sensitivity (R = 149.82 A/W), external quantum efficiency (EQE = 73206%), and response rate Τrise = 0.66 s, and Τdown = 0.45 s.

The shoot apical meristem of seed plants gives rise to the above-ground parts of the plants during development, including leaves, stems, and lateral meristems. Among them, two types of meristems, axillary meristem and vascular cambium, support the main lateral growth. In this review, we will discuss the regulatory network of lateral growth, focusing on recent progress made mainly in Arabidopsis thaliana, tomato and maize, including the identification of genes and their roles in controlling lateral meristems. In addition, we will summarize the latest evidence about how meristem affects yield-related traits, and discuss the strategies for modulating meristem regulatory genes so as to increase crop yield in agriculture.

Background: The primary sources of nitrate contamination in groundwater resources are excessive fertilizer use and unregulated land discharges of treated wastewater. Due to its harmful nature to human health and its contribution to eutrophication, the removal of nitrate from water has been of great interest in the last decades. Various techniques, such as adsorption, ion exchange, catalytic and biological denitrification, and membrane processes, have been applied for NO3 - removal. Objective: In this review study, the removal of NO3 - by membrane processes, including electrodialysis (ED), electrodeionization (EDI), reverse osmosis (RO), and ultrafiltration, has been reviewed. Methods: The pressure-driven membrane and electro-membrane processes applications to NO3 - removal have been reviewed. Results: The effects of process parameters, interferences, and limitations of membrane processes have been summarized. Conclusion: Membrane processes could be a promising alternative for NO3 - removal. After suitable membrane preparation/modification, the nitrate removal rate could reach >99%.

Background: Spatial variability of stable isotope ratios in water from River Ganges is preserved in aragonite or calcite present in otoliths and formed at equilibrium with ambient water. This technique is used for a set of long-whiskered catfish aragonite otoliths from four different locations along the course of the River Ganges. Methods: Acid digestion of otolith and the analysis of δ¹³C and δ¹⁸O in these carbonates using an isotope ratio mass spectrometer allowed the distinction of fish habitat and provided an idea about environmental conditions of water along the Ganges River. Results: The δ¹⁸O signature of otolith carbonate revealed a distinct compositional trend denoting glacial water input in the upstream segment of the Ganges, close to the water reservoir at Narora. However, the δ¹³C values remained constant, suggesting similar bicarbonate composition and food intake along the stream length. The δ¹⁸O signature in otolith from Varanasi was unexpectedly lighter and showed a tendency of the catfish population to migrate upstream segment of the river. The fish from the Narora location showed the lowest δ¹⁸O values, denoting the signature of water derived from the melting of a glacier. The heavier δ¹⁸O values were seen in the population from Kanpur. The upstream migration of fish population is indicated from the δ¹⁸O values of a fish otolith from Varanasi and Bhagalpur. The Varanasi location shows aberration in δ¹⁸O signature in otoliths, and this exists because this catfish moves to other places to avoid anthropogenic stress at this location. Conclusion: The δ¹⁸O of otolith carbonate covaries with average environmental temperature recorded at the individual location and serves as an important thermometric measurement for marking environmental conditions and stress in changing climatic parameters along the stream length of River Ganges and its tributaries.

Background: The pellet shaft furnace is widely used to roast pellets, which is essential for the blast furnace burden structure; however, the study on the roasting process in the pellet shaft furnace is very critical for obtaining high-quality pellets. Objective: A theoretical model of the pellet roasting process in the pellet furnace (8m²) has been developed on the basis of reaction engineering. The present study aims at investigating the roasting process in the pellet shaft furnace by taking into account gas flow and heat transfer so that a reasonable structural design for the shaft furnace can be obtained. Methods: A numerical model for an 8m² pellet shaft furnace has been developed on the basis of reaction engineering by taking into account gas flow, heat exchange between pellets and gas, and oxidation reaction of pellets. Results: The results show that four reaction zones (preheating, roasting, soaking, and cooling) exist obviously in the pellet shaft furnace. About 80% coolant gas flows through the gas coolant passage in the roasting zone, and the non-uniformity of coolant gas in the cooling zone exists under normal operative conditions. Furthermore, effects of some operation conditions on the distributions of process variables in the furnace are also examined. The numerical results are in agreement with industrial experiment results. Conclusion: The results reveals that the non-uniform flow of gas occurs in the cooling zone. The non-uniform flow of gas greatly affects the cooling effect. The present results can provide a theoretical basis for the prediction of the furnace process, the optimization of operation and the rational design of furnace shape. At the same time, the present work is helpful in realizing the automatic control and computer management of furnace production. In the future, the movement of pellets should be observed by means of a visualized model experiment to verify that the descending movement of pellets is approximately a potential flow in the furnace and piston flow except for the cooling zone. In addition, the experimental study of a single pellet under a widely varying range of conditions should be carried out to investigate the controlling step of oxidation reaction for pellets in the furnace.

Background: This paper reports a versatile bentonite clay-mediated growth method for selectively synthesizing zero-dimensional α-Fe2O3 nanoparticles and one-dimensional α-FeFe2O3 nanorods. Methods: In such a growth process without any other surfactant or additive, the bentonite clay is not only used as the supporter, but also as a shape mediator for α-Fe2O3 nanocrystals. The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results: The as-prepared products were used to investigate their promising adsorptive and photocatalytic applications in water treatment. According to the Langmuir equation, the maximum adsorption capacity of the α-Fe2O3/bentonite composite for Congo red (CR) is calculated to be 96.9 mg·g-1. Furthermore, the α-Fe2O3/bentonite nanocomposites also show an excellent photocatalytic property in the degradation of methyl orange (MO). Conclusion: This facile and novel synthesis method has the potential to be applied to prepare the low-cost α-Fe2O3/bentonite nanocomposite for the removal of CR and MO.