A Novel Computer-Aided Detection/Diagnosis System for Detection and Classification of Polyps in Colonoscopy.

Using a deep learning algorithm in the development of a computer-aided system for colon polyp detection is effective in reducing the miss rate. This study aimed to develop a system for colon polyp detection and classification. We used a data augmentation technique and conditional GAN to generate polyp images for YOLO training to improve the polyp detection ability. After testing the model five times, a model with 300 GANs (GAN 300) achieved the highest average precision (AP) of 54.60% for SSA and 75.41% for TA. These results were better than those of the data augmentation method, which showed AP of 53.56% for SSA and 72.55% for TA. The AP, mAP, and IoU for the 300 GAN model for the HP were 80.97%, 70.07%, and 57.24%, and the data increased in comparison with the data augmentation technique by 76.98%, 67.70%, and 55.26%, respectively. We also used Gaussian blurring to simulate the blurred images during colonoscopy and then applied DeblurGAN-v2 to deblur the images. Further, we trained the dataset using YOLO to classify polyps. After using DeblurGAN-v2, the mAP increased from 25.64% to 30.74%. This method effectively improved the accuracy of polyp detection and classification.

Enhanced photoluminescence and electroluminescence of multilayer GeSi islands on Si001 substrates by phosphorus-doping.

Ge/Si heterojunction light emitting diodes with 20-bilayers undoped or phosphorus in situ doped GeSi islands were fabricated on n(+)(-)Si(001) substrates by ultrahigh vacuum chemical vapor deposition (UHV-CVD). Enhanced room temperature photoluminescence (PL) and electroluminescence (EL) around 1.5 µm were observed from the devices with phosphorus-doped GeSi islands. Theoretical calculations indicated that the emission is from the radiative recombination in GeSi islands. The intensity enhancement of PL and EL is attributed to the sufficient supply of electrons in active layer for radiative recombination.

GeSn p-i-n photodetector for all telecommunication bands detection.

Using a 820 nm-thick high-quality Ge0.97Sn0.03 alloy film grown on Si(001) by molecular beam epitaxy, GeSn p-i-n photodectectors have been fabricated. The detectors have relatively high responsivities, such as 0.52 A/W, 0.23 A/W, and 0.12 A/W at 1310 nm, 1540 nm, and 1640 nm, respectively, under a 1 V reverse bias. With a broad detection spectrum (800-1800 nm) covering the whole telecommunication windows and compatibility with conventional complementary metal-oxide-semiconductors (CMOS) technology, the GeSn devices are attractive for applications in both optical communications and optical interconnects.

Expression of c-fos and oxidative stress on brain of rats reared on food from mercury-selenium coexisting mining area.

Wanshan mercury mine is the largest mercury deposit in Guizhou Province of China, but there were few reports on mercury toxic effect in the mining area. In order to study the neurotoxicity of food from Wanshan mercury mine area and probe into the effect of food from Wanshan mercury miner area on the changes of brain oxidative damage and expression of c-fos gene. The rats were exposed to mercury contaminated food for 20 d. The content of malondialdehyde (MDA), superoxide dismutase (SOD), GSH-peroxidase (GSH-px) and Glutathione (GSH) in rat brain was measured, and the effect of mercury contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results showed the levels of GSH, MDA, SOD and of GSH-dependent enzymes in the rat brain changed between exposure groups and control group; The mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group (P<0.01). It could be concluded that oxidative stress signals could contribute to the induction of immediate early genes (IEGs); free radicals and their by-products might not only cause oxidative damage, but also influenced gene expression; IEGs c-fos participated in the toxicity process of brain injury by mercury polluted food.

[Spatial Distribution Characteristics and Source Analysis of Dissolved Organic Matter in Beiyun River].

Dissolved organic matter (DOM) in aquatic ecosystems has gained wide concern because of its influence on the light attenuation, nutrient availability and contaminant transport. Human activities strongly influence the DOM of rivers in different ways, including increased agricultural activities and industrial and domestic emissions. However, recent socio-economic development with rapid urban development has significantly enhanced the discharge of sewage, and has caused high loads of DOM, which in turn pose a great risk to aquatic ecosystems. To effectively guide water management for protecting aquatic ecosystem health, it is very critical to investigate the distribution and source of dissolved organic matter in urban rivers. In this study, the distribution and source analysis of DOM in Beiyun River were evaluated, where covers the most populated area with a population of 14 million, representing the most urbanized watershed of Beijing. Since the main receiving source of the river is treated and untreated wastewater in Beijing City, the water quality is highly polluted by anthropogenic inputs. However, information on DOM of Beiyun river has not been reported. Therefore, this study can not only reveal the biogeochemistry of DOM in Beiyu River, but also provide useful implications of pollution control for similar urban rivers. The fingerprint features were extracted from the Excitation-Emission Matrix Spectrum of fluorescent dissolved organic matter (FDOM) in 23 sampling sites of Beiyun river during November 2013. Three separate fluorescent components were identified by Parallel factor analysis (PARAFAC) model, including two humic-like components (C1: 240, 300/385 nm; C2: 255, 350/400 nm) and one protein-like component (C3: 230, 280/340 nm). The results indicated that humic-like materials were generally the dominated component of FDOM, accounting for 76.18% of the average total fluorescence intensity. Positive relationships were found between the fluorescence intensity and the concentrations of some water quality indicators, such as total nitrogen, ammonia nitrogen and total phosphorus, indicating the same sources of these components. Thus, the migration and transformation of nitrogen & phosphorus could also influence the level of FDOM. The distribution of total fluorescence intensity showed a distinctly different spatial pattern. The fluorescence intensity decreased firstly along the upstream to midstream continuum, and then increased from the midstream to downstream. The FDOM in the upstream could be attributed to the industrial effluent and agricultural runoff inputs. Among the upstream to downstream continuum, the content of FDOM in the midstream was the lowest. Limited domestic pollution was suggested as the major source. In the downstream, the sources of FDOM could be interpreted as industrial, agricultural wastewater and livestock wastewater discharge. The relative abundance of protein-like materials was markedly increased in this area, indicating the sources of DOM was highly impacted by human activities. In addition, our study also concluded that the removal efficiency of DOM in wastewater plants is not very desirable, which implied that stronger support for DOM removal in sewage system is needed to alleviate DOM pollution and improve water quality.

Effects of mercury contaminated rice from typical chemical plant area in China on nitric oxide changes and c-fos expression of rats brain.

China is one of countries with the highest mercury production in the world. The Guizhou Province in Southwestern China is currently one of the world's most important mercury production areas. In order to study the neurotoxicity of rice from Qingzhen Chemical Plant area and probe into the signal transduction molecular mechanism of injury in rat brain stimulation by mercury contaminated rice. The rats were exposed to mercury contaminated rice for 20 d. Both of the measurements of NO and NOS were processed according to the protocol of the kit. The effect of Hg contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results showed the neural transmitter NO and NOS in brain were significantly change between exposure groups and control group; the mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group (p < 0.01). It could be concluded that nitric oxide was involved in mercury contaminated rice induced immediate early gene c-fos expressions in the rat brain. Through food chain, local ecosystem and health of local people iave been deteriorated seriously by mercury. This serious situation will last a long period. In order to alleviate mercury pollution, more work needs to do.

Effect of methylmercury on some neurotransmitters and oxidative damage of rats.

In order to study the molecular mechanism of injury in rat organs induced by methylmercury, and the relationship between neurotransmitter and oxidative damage in the toxicity process of rat injury by methylmercury was studied. The control group was physiological saline of 0.9%, the concentration of exposure groups were 5 mg/( kg x d) and 10 mg/( kg x d) respectively. The content of AChE, ACh, NOS, NO, MDA, SOD, GSH-Px and GSH in different organs of rats were determined with conventional methods. The results showed that after exposure to methylmercury for 7 d, the mercury content in brain of exposure groups increased clearly and had significant difference compared with the control group (P < 0.01). In rat's brain, serum, liver and kidney, the content of ACh and AChE were all decreased; the content of NOS and NO were all increased; the content of MDA was increased compared with the control group, the exposure groups had significant difference (P < 0.01); the content of SOD, GSH and GSH-Px was decreased compared with the control group, the exposure groups had significant difference (P < 0.01). It could be concluded that methylmercury did effect the change of neurotransmitter and free radical. They participated in the toxicity process of injury by methylmercury. The damage of neurotransmitter maybe cause the chaos of free radical and the chaos of free radical may also do more damage to neurotransmitter vice versa.

Enhanced photoluminescence of multilayer Ge quantum dots on Si(001) substrates by increased overgrowth temperature.

Four-bilayer Ge quantum dots (QDs) with Si spacers were grown on Si(001) substrates by ultrahigh vacuum chemical vapor deposition. In three samples, all Ge QDs were grown at 520 °C, while Si spacers were grown at various temperatures (520 °C, 550 °C, and 580 °C). Enhancement and redshift of room temperature photoluminescence (PL) were observed from the samples in which Si spacers were grown at a higher temperature. The enhancement of PL is explained by higher effective electrons capturing in the larger size Ge QDs. Quantum confinement of the Ge QDs is responsible for the redshift of PL spectra. The Ge QDs' size and content were investigated by atomic force microscopy and Raman scattering measurements.

Study on acute toxicity and structure-activity relationship of Daphnia magna exposed to naphthoquinones.

The acute toxicities of the six naphthoquinone compounds on Daphnia magna (D. magna) at 48 h were classified as harmful, toxic, and very toxic. The results indicated that logP played an important part in the toxicity of compounds to organism. And 1-carbonyl or the other hydrophobic substituents of the naphthoquinone compounds are likely to mediate the binding of the compound to the target via hydrogen bonding and hydrophobic interactions. Our results provided a foundation for further investigation using 3D-QSAR and HQSAR to evaluate the aquatic ecological risk and the mechanism of toxicity of naphthoquinones.

Oxidative stress on domestic ducks (Shaoxing duck) chronically exposed in a Mercury-Selenium coexisting mining area in China.

The Wanshan mercury mine is the largest mercury deposit in Guizhou Province, China. Few attempts have been made to study the toxic effects of mercury on biota in this mining area. This study was the first to investigate the oxidative stress on domestic ducks (Shaoxing duck) chronically exposed to mercury in the Wanshan mining area. Chemical analyses revealed higher concentrations of both, mercury and selenium in samples from the Wanshan area. Total mercury and selenium concentrations in duck tissues varied from 0.073 to 4.465 mg/kg and from 1.073 to 6.35 mg/kg, respectively. Analysis of covariance revealed that there were significant effects of zone on accumulation of mercury and selenium in all duck tissues (P<0.01). Moreover, analysis of covariance indicated that mercury content significantly affected the accumulation of selenium in duck muscle, brain, and liver (P<0.01). Mercury and selenium were also highly correlated in Wanshan duck liver, muscle, brain, and lung. The statistical analysis suggested that selenium might be an interactive factor in mercury toxicity. As for the biochemical analyses, it was observed that selenium-dependent glutathione peroxidase and superoxide dismutase activities and glutathione (GSH) content were significantly increased in the livers and brains of Wanshan ducks (P<0.01, 0.05). However, no significant changes were observed in malondialdehyde content (P>0.05). Although the results indicated that adaptive responses of the redox-defense system are associated with the increased enzyme activities and GSH content, the most likely explanation is that selenium plays a critical role. Therefore, the effects of the interaction environmentally occurring selenium and mercury on public health in the Wanshan area should be examined in further studies.

[Mercury pollution and its ecosystem effects in Wanshan mercury miner area, Guizhou].

Samples of water, soil, plants, crops and animals collected from Wanshan mercury miner area, Guzhou Province, were analyzed with an AMA-254 liquid/solid mercury analyzer. It was shown that mercury pollution is mainly in soil and air; except water from a pool, no anomaly mercury is found in waters. Mercury content in soil is 24.31-347.52 mg.kg-1, two or three magnitude higher than the average value of Chinese soils; mercury content in plants is 0.47-331.4 mg.kg-1, and moss can enrich much mercury. Due to the long time of exploration and smelting, abundant mercury are accumulated in the local ecosystem, and healthy of local people are threatened seriously.