Fecal virus transplantation has more moderate effect than fecal microbiota transplantation on changing gut microbial structure in broiler chickens.

Growing evidence of fecal microbiota transplantation (FMT) and fecal virus transplantation (FVT) provides a possibility to regulate animal health, whereas little is known about the impact of the 2 methods. This study aimed to investigate the effects of gut microbes on jejunal function in healthy broiler chickens, with the objective of establishing a theoretical basis for the application of FMT and FVT. Cecal feces from 28-day-old AA broilers were collected to prepare gavage juice for FMT and FVT. FMT for Group FM, FVT for group FV and PBS gavage for group CON, continuously treated for 6 days start at 5-day-old chicks. Samples were collected at d 11 and d 21. The results showed that the treatment d 2 and the overall fecal score in treatment groups were significantly lower than CON group (P < 0.05). The jejunum morphology showed that FMT increased crypt depth, decreased villus height, V/C (P < 0.05) and FVT increased villus height (P < 0.05) at d 11. At d 21, villus height and crypt depth significantly higher (P < 0.05) in group FM and group FV. The expression of Claudin1, Occludin, ZO2, and Muc2 in the FV group was significantly increased (P < 0.05) at 11-day-old. FMT increased the secretion of sIgA at 11-day-old, and this influence lasted up to 21-day-old (P < 0.05). At 11-day-old, the expression of b0+AT of basic amino acid transport carrier and chymotrypsin activity (P < 0.05) had a significant correlation. At 21 d of age, FVT significantly increased the expression of PepT1 and SGLT1 (P < 0.05). At 11-day-old, FM group showed significantly higher faith pd index (P = 0.004) and Shannon index (P = 0.037), and separated from FV and CON according to PCoA. Among differentiating bacteria, Bacteroides significantly enriched (P < 0.05) in group FM, which positively correlated with the expression of ZO2, Muc2, Occludin, and Claudin1; R_Ruminococcus, L_Ruminococcus, Butyricicoccuss significantly enriched (P < 0.05) in group CON, which significantly higher than processing groups, R_Ruminococcus and L_Ruminococcus negatively correlated with the expression of Occludin (P < 0.05), and R_Ruminococcus, Butyricicoccus negatively correlated with the expression of Claudin1 (P < 0.05). At 21-day-old, PCoA based on Bray-Curtis shows that microbes taxa of 3 groups are isolated with each other and treatment groups were significant different with CON group based on Unweighted UniFrac and weighted UniFrac. The expression of PepT1 was significantly negatively (P < 0.05) correlated with Ruminococcus, and the expression of sIgA was significantly negatively (P < 0.05) correlated with Parabacteroides. In conclusion, FMT regulated intestinal flora rapidly, while it had little effect on intestinal function and a higher potential damaging risk on jejunal. FVT regulated intestinal flora structure softer, improved tight junction expression, but the mechanism of action needs further exploration.

Effects of coal mining and climate-environment factors on the evolution of a typical Eurasian grassland.

Coal mining can significantly impact vegetation evolution, yet the limited information on its patterns and driving factors hampers efforts to mitigate these effects and reclaim abandoned mines. This study aimed to 1) examine vegetation evolution in a semiarid steppe watershed in northeast China; and 2) characterize the driving factors behind this evolution. We analyzed the impact of twelve selected driving factors on fractional vegetation coverage (FVC) from 2000 to 2021 using a dimidiate pixel model, Sen's slope analysis, Mann-Kendall trend test, coefficient of variation analysis, and Geodetector model. At a significance level of α = 0.05, our findings revealed a south-to-north decline pattern in FVC, a significant decrease trend in proximity to coal mines, and a notable increase trend adjacent to river channels. Approximately 37% of the watershed exhibited low FVC, while the overall temporal trend across the watershed was deemed insignificant. Areas surrounding the mines experienced a substantial reduction in FVC due to coal mining activities, while FVC variations across the watershed were linked to precipitation, temperature, and soil type. FVC predictions improved notably when interactions between multiple two-way factors were considered. Each driving factors displayed an optimal range (e.g., precipitation = 63-71 mm) for maximizing FVC. Given the study watershed's status as a national energy base, understanding vegetation responses to coal mining and climate-environment changes is crucial for sustaining fragile terrestrial ecosystems and socioeconomic development. Achieving a long-time balance between coal extraction and ecological protection is essential. The study outcomes hold significant promise for advancing ecological conservation, vegetation restoration, and mitigation of environmental degradation in semiarid regions affected by extensive coal mining and climate fluctuations. These findings contribute to the strategic management of such areas, promoting sustainable practices amidst evolving environmental challenges.

[Hydrochemical Characteristics and Control Factors of Groundwater in the Northwest Salt Lake Basin].

Taking the Tugeligaole sub-basin of the Jilantai Salt Lake Basin in Inner Mongolia as the typical study area, the groundwater samples of 22 points were collected, and their main characteristic indexes were tested during the wet season and the dry season separately in 2021. Mathematical statistics, Piper triangular diagrams, a Gibbs plot, ionic relations, and factor analysis were used to analyze and discuss the hydrochemical characteristics and formation mechanism of groundwater in different periods. Based on the evaluation of the groundwater quality using the water quality index(WQI) method, the potential risks of groundwater Cr6+ and F- were evaluated using the health risk evaluation model. The results showed that the groundwater was overall weakly alkaline; the dominant anions and cations during the different periods were Cl- and Na+, and the water chemistry type was mainly Cl--Na+; the groundwater quality was generally good, and the difference in water quality between the wet season and the dry season was not significant; adults and children had higher carcinogenic health risks in the dry season than that in the wet season, and the health risks of children were significantly higher than those in adults. The maximum carcinogenic health risk of drinking water exposure to Cr6+ in adults and children was higher than the maximum acceptable risk level(5×10-5). The chemical evolution of groundwater was mainly affected by evaporative concentration, evaporative salt rock dissolution, and cation exchange, and the main control factors were evaporative concentration(contribution rate of 54.19%), native geological environment factors(contribution rate of 12.99%), and carbonate rock dissolution(contribution rate of 11.66%). The study results have significance to some degree to the sustainable exploitation and utilization of groundwater resources and environmental protection of the salt lake basin.

N-Rich and Sulfur-Doped Nano Hollow Carbons with High Oxidase-like Activity Prepared Using a Green Template of CaCO3 for Bacteriostasis.

Nanozymes, enzyme-mimicking nanomaterials, have attracted increasing attention due to their low cost, high stability, and catalytic ability compared with natural enzymes. However, the catalytic efficiency of the nanozymes is still relatively low, and catalytic reaction mechanisms remain unclear. To address these issues, herein we prepared nitrogen-riched and sulfur-codoped nano hollow carbons (N/S-HCS) using a green and useful template of CaCO3. N/S-HCS exhibits enhanced oxidase-like activity and catalytic kinetic performance. It could directly oxidize the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to the heavy blue colored ox-TMB without H2O2. The maximum reaction rate (Vmax) is 186.7 × 10-8 M·s-1, and Michaelis-Menten constant (Km) is 0.162 mM. DFT results show that N and S codoping could work synergistically to provide more active sites, resulting in the superior ability to adsorb oxygen and enhanced catalytic activity. Meantime, we develop a multispectral characterization strategy to unravel catalytic reaction mechanisms about N/S-HCS. It successfully induces the generation of superoxide (•O2-) and hydroxyl (•OH) during the colorimetric reaction which are the key intermediate products of the catalytic reaction. Furthermore, N/S-HCS increased the cellular reactive oxygen species level significantly and induced bacteriostasis to more than 95% of Escherichia coli.

One case report of laparoscopic biological patch repair for the ureterosciatic hernia and literature review.

Ureterosciatic hernia is a very rare disease worldwide. We report a successful case of laparoscopic biological repair of large ureteral hernia. Preoperative CT examination showed ureterosciatic hernia with incarceration and proximal ureteral dilatation. Laparoscopic ureteral incarceration release, ureteral stent placement and biological patch repair of sciatic foramen hernia were performed. Under the observation of laparoscope, the stent was placed through urethra with cystoscope to restore the course of ureter. A biological patch was placed behind the ureter to cover the closed hernia ring. We have been followed up for 2 months after operation. According to the reexamination, the effect is obvious. Laparoscopic biological patch repair for ureteral sciatic foramen hernia has the advantages of less trauma, convenient operation and ideal prognosis in theory.

Gandan Oral Liquid Improves Exudative Pneumonia by Upregulating Bacteria Clearance via Regulating AQP5 and MUC5AC in Rats.

Gandan oral liquid (GOL) is a mixture of crude extracts from licorice and Radix isatidis. Clinically, it has been widely used in the treatment of exudative pneumonia (EP) in animals. But the molecular mechanism of these effects is unclear. Therefore, antibacterial activity and therapeutic effect were tested in vitro and in vivo. Exudative pneumonia was established with the intraperitoneal injection of LPS, followed by continuous intranasal inoculation of Klebsiella pneumoniae (KP). After that, Gandan oral liquid, acetylcysteine, and levofloxacin were given through the intragastric route for five days, and clinical symptoms were observed and counted. The bacterial content of alveolar lavage fluid was determined, hematology analysis was performed, and lung histology examination was performed. Western blotting, immunohistochemistry, and immunofluorescence were used to detect the expression levels of AQP3, AQP5, and MUC5AC in lung tissues. ELISA kit was used to detect serum and BALF cytokines levels. The results showed that GOL (242 mg/mL) had no antibacterial activity on Klebsiella pneumonia (KP), and the effect was significantly worse than levofloxacin. However, the therapeutic test in vivo of the rat model of bacterial EP showed different results. After treatment, GOL administration ameliorated EP and increased the expression of mucoprotein -5AC (MUC5AC), and GOL promoted water secretion of the respiratory tract by increasing the expression of aquaporin-5 (AQP5) and decreasing the levels of proinflammatory cytokines (TNF-α, IL-6, and IL-1ß). Conclusion. GOL accelerates the water secretion of respiratory tract, inhibits the inflammatory response, induces removal of bacteria of respiratory tract via the AQPs/MUC pathway, and ultimately ameliorates EP.

[Chlorhexidine-grafted phenolamine coating to improve antibacterial property of the titanium surface].

Objective: To investigate the physicochemical properties of pure titanium surface grafted with chlorhexidine (CHX) by phenolamine coating, and to evaluate its antibacterial activity and osteoblast-compatibility in vitro. Methods: Control group was obtained by alkali and thermal treatment, and then immersed in the mixture of epigallocatechin-3-gallate/hexamethylene diamine (coating group). Phenolamine coating was deposited on the surface, and then it was immersed in CHX solution to obtain the grafted surface of CHX (grafting group). The surface morphology was observed by scanning electron microscope, the surface element composition was analyzed by X-ray photoelectron spectroscopy, and the surface hydrophilicity was measured by water contact angle test. Live/dead bacterial staining, nephelometery, and inhibition zone method were executed to evaluate the antibacterial property. Cytotoxicity was evaluated by MTT assay and cell fluorescence staining. Bacteria-MC3T3-E1 cells co-culture was conducted to evaluate the cell viability on the samples under the circumstance with bacteria. Results: Scanning electron microscope observation results showed that deposits of coating group and grafting group increased successively and gradually covered the porous structure. X-ray photoelectron spectroscopy results showed the peak of N1s enhanced and the peak of Cl2p appeared in grafting group. Water contact angle test results showed that the hydrophilic angle of three groups increased in turn, and there was significant difference between groups ( P<0.05). Live/dead bacteria staining results showed that the grafting group had the least amount of bacteria adhered to the surface and the proportion of dead bacteria was high. The grafting group had a transparent inhibition zone around it and the absorbance ( A) value did not increase, showing significant difference when compared with control group and coating group ( P<0.05). MTT assay and cell fluorescence staining results showed that the number of adherent cells on the surface of the grafting group was the least, but the adherent cells had good proliferation activity. Bacteria-cell co-culture results showed that there was no bacteria on the surface of grafting group but live cells adhered well. Conclusion: CHX-grafted phenolamine coating has the ability to inhibit bacterial adhesion and proliferation, and effectively protect cell adhesion and proliferation in a bacterial environment.

Development and validation of a model to predict acute kidney injury following wasp stings: A multicentre study.

OBJECTIVE: To establish and validate a model to predict acute kidney injury (AKI) following wasp stings. METHODS: In this multicentre prospective study, 508 patients with wasp stings from July 2015 to December 2019 were randomly divided into a training set (n = 381) and a validation set (n = 127) for internal and external validation. Risk factors were identified, and a model was established to predict the probability of AKI following multiple wasp stings using an individual nomogram and a predictive formula. The performances of the model were assessed by using the area under the curve (AUC), accuracy (ACC) of the receiver operating characteristic curve and decision curve analysis. RESULTS: The number of stings, aspartate aminotransferase >147 U/L, lactate dehydrogenase >477 U/L, time from stings to admission >12 h and activated partial thromboplastin time >49 s were demonstrated to be independent risk factors for AKI following wasp stings (all P value < 0.05) and were incorporated into the model. The performances of the model were validated (AUC = 0.950 [95% CI: 0.923 to 0.969], ACC = 0.916 and AUC = 0.953 [95% CI: 0.900 to 0.982], ACC = 0.906 in the training set and validation set, respectively). The predictive formula and the nomogram of the model could be utilized to predict AKI following wasp stings, which have sufficient accuracies, good predictive capabilities and good net benefits. CONCLUSION: The predictive formula and the individual nomogram of the model might serve as promising predictive tools to assess the probability of AKI following wasp stings.

The effect of charged defects on the stability of implanted helium and yttrium in cubic ZrO2: a first-principles study.

The effect of charged defects on the stability of implanted He and Y atoms has been fully investigated to gain insight into the occupation mechanism of defects in cubic ZrO2 using first-principles calculations. For the intrinsic point defects in ZrO2, the configurations of VO2+, IO2-, VZr4-, and IZr4+ are dominant, which have the lowest formation energy over the widest Fermi level range, respectively. He atoms at neutral Zr vacancies have the lowest incorporation energy (0.438 eV), illustrating that the VZr0 is probably the most stable trapping site for He atoms. For the Y atoms implanted in ZrO2, the most stable configuration of YZr1- is obtained over the widest Fermi level range. In the Y-doped ZrO2, the incorporation energy of He at the site of Oct2 interstitial is the lowest (1.058 eV). For He atoms trapped at vacancies, He-VZr0 has the lowest incorporation energy of 0.631 eV. These results indicate that He atoms preferentially occupy the sites of VZr0. The state of electric charge plays a significant role in the formation of defects in the ionic compound. The present simulation results provide a theoretical foundation for the effect of charged defects on the stability of He atoms, which contributes to the understanding of the microscopic solution behaviour of He atoms in perfect ZrO2 and Y-doped ZrO2.

Recurrent abdominal pain due to small bowel volvulus after transabdominal preperitoneal hernioplasty: A case report and review of literature.

BACKGROUND: Compared with open mesh repair, transabdominal preperitoneal (TAPP) hernioplasty results in less chronic postoperative inguinal pain and faster postoperative recovery. However, it may still lead to rare but serious complications. Here we report a case of intestinal volvulus with recurrent abdominal pain as the only clinical symptom, which occurred 3 mo after TAPP repair for bilateral inguinal hernia. CASE SUMMARY: A 50-year-old male patient underwent laparoscopic TAPP for bilateral inguinal hernias. After the operation, he experienced recurring pain in his lower right abdomen around the surgical area, which was relieved after symptomatic treatment. Three months after the surgery, the abdominal pain became severe and was aggravated over time. The whirlpool sign of the mesentery was seen on contrast-enhanced computed tomography (CT). Laparoscopic exploration confirmed that a barb of the V-Loc™ suture penetrated the peritoneum, which caused the adhesion of the small intestinal wall to the site of peritoneal injury, forming intestinal volvulus. Since there was no closed-loop obstruction or intestinal ischemia, recurrent abdominal pain became the only clinical manifestation in this case. After laparoscopic lysis of adhesions and reduction of intestinal volvulus, the patient recovered and was discharged. CONCLUSION: The possibility of intestinal volvulus should be considered in patients who experience recurrent abdominal pain following TAPP surgery during which barbed V-Loc sutures are used for closing the peritoneum. Contrast-enhanced CT and active laparoscopic exploration can confirm the diagnosis and prevent serious complications.

Lichtenstein inguinal hernia repairs with porcine small intestine submucosa: a 5- year follow-up. a prospective randomized controlled study.

Porcine small intestine submucosa (SIS) biologic patch has been used in inguinal hernia repair. However, there are little data available to assess the long-term effect after repair. This study aimed to explore the long-term effect of SIS patch in open inguinal hernia repair. Sevent-six patients with unilateral inguinal hernia were treated with Lichtenstein tension-free hernia repair using SIS patch (Beijing Datsing Bio-Tech Co., Ltd.) and Surgisis patch (COOK, USA) in Tianjin Union Medical Center and China-Japan Friendship Hospital. In the trial, the long-term efficacy of the treatment group and the control group were compared. A total of 66 patients in both groups received long-term follow-up (> 5 years) after surgery, with a follow-up rate of 86.8%. During the follow-up period, there was one case of recurrence, one case of chronic pain in the control group. There was no statistically significant difference (P > 0.05) in terms of recurrence, chronic pain, foreign body sensation and infection between the two groups of patients. After long-term observations, it has been found that the porcine small intestinal submucosa (SIS) biological patch is safe and effective for inguinal hernia Lichtenstein repair, and has a low recurrence rate and complication rate.

First-principles investigation of oxygen interaction with hydrogen/helium/vacancy irradiation defects in Ti3AlC2.

First-principles calculations have been performed to investigate the interaction between solute impurity O and H/He/vacancy irradiation defects in Ti3AlC2. The formation energy and occupation of O atoms within different defects as well as the trapping progress of O/H clusters are discussed. It is found that the O atom preferentially occupies the hexahedral interstitial site (Ihex-1) in bulk Ti3AlC2, whereas it prefers to occupy the neighbouring tetrahedral interstitial site (Itetr-2) within pre-exisiting Al monovacancy (VAl), Al divacancy (2VAl-Al) and the 2VAl-C divacancy composed of Al and C vacancies. The appearance of C vacancy could greatly reduce the oxygen formation energy and make an O atom more inclined to occupy the center of C vacancy. Vacancy could capture more O atoms than H/He atoms, where VAl and 2VAl-Al could hold up to fifteen and eighteen O atoms, respectively. Meanwhile, the O could also promote the formation of Al vacancy. On the other hand, O atoms tend to occupy the interstitial sites near the Al atomic layer and have attraction to Al atoms, which is likely to enable the O atoms to combine with the Al atoms to form a Al2O3 protective layer, thus effectively inhibiting further oxidation inside the Ti3AlC2. In addition, the H-O exhibits repulsion interaction, but strong attraction occurs in the He-O interaction. Therefore, the O atom has an inhibitory effect on the formation of the H cluster, while it could bind more He atoms to form a large number of He bubbles. Besides, the O impurity greatly reduces the trapping ability of vacancy to H atoms, and O and He have a synergistic interaction for inhibiting the aggregation of H clusters. The present results are expected to provide a new insight into the behaviour of Ti3AlC2 under irradiation and oxidation conditions so that structural materials could be better designed.

Aggregation of retained helium and hydrogen in titanium beryllide Be12Ti: a first-principles study.

Titanium beryllide, Be12Ti, has been proposed as a prospective neutron multiplier in fusion reactors. First-principles calculations have been performed to investigate the nucleation mechanism of a He bubble in bulk Be12Ti. Meanwhile, the influence of the presence of H atoms on the nucleation of the He bubble, i.e., the synergistic effect of He and H atoms, has also been investigated. It has been found that the He bubble will initially nucleate around a monovacancy (VBe2). When more He atoms have been implanted, two newly induced vacancies (VBe1 and VBe3) could be successively observed. The nucleation of the He bubble will occur around the divacancy of VBe2VBe1 and the trivacancy of VBe2VBe1VBe3. Dumbbell structures in the He bubble evolve with the number of implanted He atoms and finally disappear. The presence of H atoms will significantly influence the nucleation of the He bubble. It is interesting that some tetrahedral and octahedral structures have also been observed. The maximal number of H atoms trapped by a He bubble has been obtained. These phenomena could be further explained by the continuous shrinking of the isosurface of charge density. The present results provide a microscopic physical foundation to understand the mechanism of He and H atoms retention in neutron multiplier materials. This investigation could be helpful for the design and fabrication of more promising beryllides which could withstand a severe external environment.

New insight into the interaction between divacancy and H/He impurity in Ti3AlC2 using first-principles studies.

First-principles calculations have been conducted to investigate the interaction between vacancy defects and H/He impurity in Ti3AlC2. The formation energies of monovacancy and divacancy have been calculated. It is found that Al monovacancy (VAl), Al divacancy (2VAl-Al), and the divacancy composed of Al and C atoms (2VAl-C) are most easily formed in all vacancies. In addition, the interactions between multiple vacancies are weak. The formation of vacancy is relatively independent and not affected by other vacancies. The configurations and energies of H-mV (m = 0, 1, 2) complexes have been studied to assess the energetically favorable sites for H atoms. Within pre-existing VAl or 2VAl-Al, the most favorable site for H atoms is the Itetr-2 site, but the H atom tends to occupy the Ioct-4 site within 2VAl-C. The formation energies of the secondary vacancy defect nearest to an Al vacancy or C vacancy are significantly influenced by H impurity content. H clusters trapped in a primary Al vacancy can promote the formation of vacancy and prefer to form platelet-like bubbles parallel to the Al plane, while H clusters trapped in a primary C vacancy have higher probability to form spherical ones. The 2VAl-Al and 2VAl-C divacancies exhibit stronger H trapping ability than monovacancy. The 2VAl-Al divacancy could capture up to seven H atoms, and 2VAl-C could capture six H atoms. Meanwhile, the He-2VAl-Al complex could only capture four H atoms to form H-He hybridized bubbles, and He impurities effectively suppress further aggregation of H atoms. The present results provide microstructural images of nH-mV and nH-He-mV complexes as well as the evolution progress of H bubbles in Ti3AlC2, which is especially helpful for us to understand the behavior of H/He in Ti3AlC2 under irradiation.

Bio-inspired attitude measurement method using a polarization skylight and a gravitational field.

High precision and reliability attitude measurement play an important role in autonomous unmanned navigation. Finding inspiration from desert ants, known as highly efficient navigators who can find their way after foraging for hundreds of meters from their home in hostile environments, we propose an attitude measurement method using polarization skylight and gravitational field. Contrary to the previous method, we utilize three-dimensional polarization vectors and any one-dimensional output of the accelerometers to calculate attitudes. In addition, we designed an accelerometer component selection algorithm, which is to select the one-dimensional component with the minimum motion acceleration from the output of the three-dimensional accelerometer. With this method, even if the carriers remain in a maneuvering state, the motion acceleration of the vehicle will have less impact on the accuracy of attitude measurement. To evaluate the performance of our method, the outdoor experiment was carried out to compare our method with existing traditional methods. Comparison results show that our method has higher measurement accuracy than others and is still applicable in the case of carriers maneuvering in practice under a clear sky.

Structure and thermal expansion behavior of Ca4La6-xNdx(SiO4)4(PO4)2O2 apatite for nuclear waste immobilization.

In this study, Ca4La6-xNdx(SiO4)4(PO4)2O2 (x = 0, 1, 2, 3, 4, 5, and 6) apatites were explored for nuclear waste immobilization, and Nd3+ ions were used as the surrogate of radionuclides (such as Am3+, Cm3+, and Pu3+). The synthesized samples conform to the P63/m (176) symmetry in the hexagonal system according to the characterizations by means of X-ray diffraction, Raman spectra, and Fourier-transform infrared spectra. Rietveld analyses indicate that both Ca2+ and Ln3+ (La, Nd) cations are located at the M4f and M6h sites, which is different from earlier studies. The M6h sites prefer to be occupied by Ln3+ (La, Nd) cations with higher valence. Besides, the content of the impurity phase Ca3(PO4)2 reduces from 2.815 wt% to 0 with the incorporation of Nd3+ ions. These results demonstrate that apatites possess excellent ability to accommodate radionuclides with various valences and radii at the M4f and M6h sites. Moreover, we investigated the thermal expansion behavior by high-temperature X-ray diffraction. There is no phase transformation in the range of 298-1173 K, and the Ca4La6-xNdx(SiO4)4(PO4)2O2 apatites exhibit lower thermal expansion coefficients than other candidates that have been extensively studied. Furthermore, the thermal expansion coefficient gradually decreases with the accommodation of Nd3+ ions. All the results suggest that apatites are promising candidates for nuclear waste immobilization.

Formation experiment with heading angle reference using sky polarization pattern at twilight.

Consistency has always been an important topic in formation cooperation research. Traditional navigation methods, such as inertial navigation and geomagnetic navigation, have the disadvantages of error accumulation and low stability, thus reducing the consistency of formation. We propose to use the skylight polarization pattern to provide heading angle reference for formation cooperation of multi-agents. The experimental results show that the polarization navigation has good stability and no error accumulation. First, we analyzed the consistency of using the skylight polarization pattern to provide a heading reference for formation experiments. Then, based on the bionic polarization navigation sensor, we measured the difference of the skylight polarization azimuth of different observers at twilight. Further, a mobile robot platform was built with its heading angle provided by a polarization navigation sensor. Finally, we present an overview of a 3-robots platform formation experiment at twilight.

[Community Composition of nirS-type Denitrifying Bacteria in the Waters of the Lower Reaches of the Fenhe River and Its Relationship with Inorganic Nitrogen].

In order to assess the waters of the lower reaches of the Fenhe River and the interaction with inorganic nitrogen, Illumina high-throughput sequencing technology was used to analyze samples based on the analysis of water quality indicators of nine rivers. The community structure and diversity of nirS-type denitrifying bacteria was diagnosed and statistical analysis was carried out to analyze the relationship between these communities and inorganic nitrogen content. The results show that the lower reaches of the Fenhe River are seriously polluted with inorganic nitrogen and the overall water quality standard was classified as V. The range of calculated Shannon index values was 3.36-7.54, indicating that the diversity of the denitrifying bacterial community is high in this basin. The relative abundance of the dominant genera represented 89.8% of the total community, which included Rhodobacter, Pseudomonas, and Thauera. The DO, pH, and inorganic nitrogen content were the main factors affecting the denitrifying bacterial community in the lower reaches of the Fenhe River. The dominant genus, Rhodobacter, and the genus Thauera were negatively correlated with NO3--N and NO2--N, and were positively correlated with NH4+-N. Pseudodomomas was the dominant genus in the Jishan and Hejin areas, and in the Fenhe River feeding into the Yellow River, and was negatively correlated with NO3--N and NO2--N but positively correlated with NH4+-N. The dominant genera of nirS-type denitrifying bacteria in the lower reaches of the Fenhe River promote denitrification and play a role in reducing the content of nitrate nitrogen in the water.

[Analysis of Nitrate Pollution Sources in the Rainy Season of the Lower Fenhe River].

Through the application of multi-isotope tracing, IsoSource model calculation, and microbial detection, the source of nitrate pollution in the lower reaches of the Fenhe River was screened, and the contribution rate of each source was calculated. The results showed that the main forms of nitrogen-containing substances in the lower reaches of the Fenhe River are NO3--N and NH4+-N and that the NO3--N content in 77.8% of the samples exceed the national drinking water standard. The abundance of denitrifying microorganisms in Jishan, Hejin, and the Fenhe River into the Yellow River is high, and many dominant bacteria participate in denitrification, resulting in nitrogen fractionation. The contents of δ15N-NO3- and δ18O-NO3- in the isotopes ranged from 5.30‰ to 12.90‰ and from 1.3‰ to 1.8‰, respectively. Manure and sewage were the main sources of nitrate in the Linfen section, accounting for 68% of the total nitrate source. In the Xiangfen section, the main sources of nitrate in the river were manure and sewage, at 37.5%, and agricultural fertilizer, at 37%. Agrochemicals are the main sources of nitrate in the Hejin section of the river, with a contribution ratio of 49.3%.

A Bio-Inspired Polarization Sensor with High Outdoor Accuracy and Central-Symmetry Calibration Method with Integrating Sphere.

A bio-inspired polarization sensor with lenses for navigation was evaluated in this study. Two new calibration methods are introduced, referred to as "central-symmetry calibration" (with an integrating sphere) and "noncontinuous calibration". A comparison between the indoor calibration results obtained from different calibration methods shows that the two proposed calibration methods are more effective. The central-symmetry calibration method optimized the nonconstant calibration voltage deviations, caused by the off-axis feature of the integrating sphere, to be constant values which can be calibrated easily. The section algorithm proposed previously showed no experimental advantages until the central-symmetry calibration method was proposed. The outdoor experimental results indicated that the indoor calibration parameters did not perform very well in practice outdoor conditions. To establish the reason, four types of calibration parameters were analyzed using the replacement method. It can be concluded that three types can be easily calibrated or affect the sensor accuracy slightly. However, before the sensor is used outdoors every time, the last type must be replaced with the corresponding outdoor parameter, and the calculation needs a precise rotary table. This parameter, which is mainly affected by the spectrum of incident light, is the main factor determining the sensor accuracy. After calibration, the sensor reaches an indoor accuracy of ±0.009° and a static outdoor accuracy of ±0.05° under clear sky conditions. The dynamic outdoor experiment shows a ±0.5° heading deviation between the polarization sensor and the inertial navigation system with a ±0.06° angular accuracy.