Retrospective analysis of mortality among children under 5 years of age in Huangshi over the period 2002-2022, China.

BACKGROUND: The United Nations' Millennium Development Goals and Sustainable Development Goals both underscore the critical need to reduce the under-five mortality rate globally. China has made remarkable progress in decreasing the mortality rate of children under five. This study aims to examine the trends in child mortality rates from 2002 to 2022 and the causes of deaths among neonates, infants, and children under 5 years of age from 2013 to 2022 in Huangshi. METHODS: The data resource was supported and provided by the Huangshi Health Commission, Huangshi Maternal and Child Health Hospital, and the Huangshi Statistics Bureau. Figures were drawn using Origin 2021. RESULTS: The mortality rate among children under 5 years old significantly decreased, from 21.38 per 1,000 live births in 2002 to 3.53 per 1,000 live births in 2022. The infant mortality rate also saw a significant decline, to 15.06 per 1,000 live births. Among the 1,929 recorded child deaths from 2013 to 2022, the top three causes were: F2 (Disorders related to short gestation and low birth weight), accounting for 17.26% (333 deaths); I1 (Accidental drowning and submersion), for 14.83% (286 deaths); and I3 (Other accidental threats to breathing), for 12.29% (237 deaths). Of the 1,929 deaths, 1,117 were male children, representing 57.91%. The gender disparity in the Under-5 Mortality Rate (U5MR) was calculated to be 1.38 (boys to girls). The leading causes of death under the age of five shifted from F2 (Disorders related to short gestation and low birth weight) to I1 (Accidental drowning and submersion) as children aged, highlighting the need for policymakers and parents to intensify care and vigilance for children. CONCLUSIONS: Huangshi has achieved significant progress in lowering child mortality rates over the past two decades. The study calls for policymakers to enact more effective measures to further reduce the mortality rate among children under 5 years of age in Huangshi. Furthermore, it advises parents to dedicate more time and effort to supervising and nurturing their children, promoting a safer and healthier development.

A Tension Sensor Array for Cable-Driven Surgical Robots.

Tendon-sheath structures are commonly utilized to drive surgical robots due to their compact size, flexibility, and straightforward controllability. However, long-distance cable tension estimation poses a significant challenge due to its frictional characteristics affected by complicated factors. This paper proposes a miniature tension sensor array for an endoscopic cable-driven parallel robot, aiming to integrate sensors into the distal end of long and flexible surgical instruments to sense cable tension and alleviate friction between the tendon and sheath. The sensor array, mounted at the distal end of the robot, boasts the advantages of a small size (16 mm outer diameter) and reduced frictional impact. A force compensation strategy was presented and verified on a platform with a single cable and subsequently implemented on the robot. The robot demonstrated good performance in a series of palpation tests, exhibiting a 0.173 N average error in force estimation and a 0.213 N root-mean-square error. In blind tests, all ten participants were able to differentiate between silicone pads with varying hardness through force feedback provided by a haptic device.

COVID-19 pandemic amplified mortality rates among adolescents with bipolar disorder through family-related factors.

BACKGROUND: Recently, a growing number of adolescents have been afflicted with mental disorders, with annual morbidity rates on the rise. This trend has been exacerbated by the global coronavirus disease 2019 (COVID-19) pandemic, leading to a surge in suicide and self-harm rates among this demographic. AIM: To investigate the impact of the COVID-19 pandemic on adolescent bipolar disorder (BD), along with the underlying factors contributing to heightened rates of suicide and self-harm among adolescents. METHODS: A comprehensive statistical analysis was conducted utilizing clinical interviews and self-reports obtained from patients or their guardians. Diagnostic criteria for BDs were based on the Diagnostic and statistical manual of mental disorders, international classification of diseases-11, and the National institute of mental health research domain criteria. Statistical analyses were performed using SPSS 26.0 software, with significance set at P < 0.05. RESULTS: A cohort of 171 adolescents diagnosed with BD between January 1, 2018, and December 31, 2022, was included in the analysis. The gender distribution was 2.8:1 (female to male), with ages ranging from 11 to 18 years old. Major factors contributing to adolescent BDs included familial influences, academic stress, genetic predisposition and exposure to school-related violence. Notably, a significant increase in suicide attempts and self-harm incidents was observed among adolescents with BD during the COVID-19 pandemic. Statistical analysis indicated that the pandemic exacerbated familial discord and heightened academic stress, thereby amplifying the prevalence of suicidal behavior and self-harm among adolescents. CONCLUSION: The COVID-19 pandemic has exacerbated familial tensions and intensified the incidence of suicide and self-harm among adolescents diagnosed with BD. This study underscores the urgent need for societal, familial and educational support systems to prioritize the well-being of adolescents and offers valuable insights and guidelines for the prevention, diagnosis and treatment of adolescent BDs.

Liquid-infused interfacial floatable porous membrane as movable gate for ultrafast immiscible oil/water separation.

Liquid separation methods are widely used in industrial and everyday applications, however, their applicability is often constrained by low efficiency, membrane fouling, and poor energy efficiency. Herein, a conceptually novel liquid-infused interfacial floatable porous membrane (LIIFPM) system for high-performance oil/water separation is proposed. The system functions by allowing a liquid to wet and fill a superamphiphilic porous membrane, thereby creating a stable liquid-infused interface that floats at the oil/water interface and prevents the passage of immiscible liquids. The lower-layer liquid can outflow directly, while the flow of the upper-layer liquid is stopped by the membrane. Remarkably, the efficiency of the LIIFPM system is independent of the membrane pore size, enabling ultrafast immiscible oil/water separation in an energy-saving and antifouling manner.

Gene delivery to breast cancer by incorporated EpCAM targeted DARPins into AAV2.

OBJECTIVE: The aim of this study is to evaluate an AAV vector that can selectively target breast cancer cells and to investigate its specificity and anti-tumor effects on breast cancer cells both in vitro and in vivo, offering a new therapeutic approach for the treatment of EpCAM-positive breast cancer. METHODS: In this study, a modified AAV2 viral vector was used, in which EpCAM-specific DARPin EC1 was fused to the VP2 protein of AAV2, creating a viral vector that can target breast cancer cells. The targeting ability and anti-tumor effects of this viral vector were evaluated through in vitro and in vivo experiments. RESULTS: The experimental results showed that the AAV2MEC1 virus could specifically infect EpCAM-positive breast cancer cells and accurately deliver the suicide gene HSV-TK to tumor tissue in mice, significantly inhibiting tumor growth. Compared to the traditional AAV2 viral vector, the AAV2MEC1 virus exhibited reduced accumulation in liver tissue and had no impact on tumor growth. CONCLUSION: This study demonstrates that AAV2MEC1 is a gene delivery vector capable of targeting breast cancer cells and achieving selective targeting in mice. The findings offer a potential gene delivery system and strategies for gene therapy targeting EpCAM-positive breast cancer and other tumor types.

Catalytic Oxidation Activity of NO over Mullite-Supported Amorphous Manganese Oxide Catalyst.

Nitric oxide (NO) can pose a severe threat to human health and the environment. Many catalytic materials that contain noble metals can oxidize NO into NO2. Therefore, the development of a low-cost, earth-abundant, and high-performance catalytic material is essential for NO removal. In this study, mullite whiskers on a micro-scale spherical aggregate support were obtained from high-alumina coal fly ash using an acid-alkali combined extraction method. Microspherical aggregates and Mn(NO3)2 were used as the catalyst support and the precursor, respectively. A mullite-supported amorphous manganese oxide (MSAMO) catalyst was prepared by impregnation and calcination at low temperatures, in which amorphous MnOx is evenly dispersed on the surface and inside of aggregated microsphere support. The MSAMO catalyst, with a hierarchical porous structure, exhibits high catalytic performance for the oxidation of NO. The MSAMO catalyst, with a 5 wt% MnOx loading, presented satisfactory NO catalytic oxidation activity at 250 °C, with an NO conversion rate as high as 88%. Manganese exists in a mixed-valence state in amorphous MnOx, and Mn4+ provides the main active sites. The lattice oxygen and chemisorbed oxygen in amorphous MnOx participate in the catalytic oxidation of NO into NO2. This study provides insights into the effectiveness of catalytic NO removal in practical industrial coal-fired boiler flue gas. The development of high-performance MSAMO catalysts represents an important step towards the production of low-cost, earth-abundant, and easily synthesized catalytic oxidation materials.

A cable-driven highly compact single port laparoscopic surgical robot with sequentially inserted arms.

BACKGROUND: The single port surgical robot causes only one incision and brings many benefits to patients. It is very challenging to design a single port surgical robot that causes a smaller incision than current products. METHODS: This paper presents a highly compact single port laparoscopy surgical robot, which makes full use of the space of the port and only needs a 15 mm-diameter port. The robot is composed of a camera manipulator and two operating manipulators. The non-fully cylindrical manipulators enter the port sequentially, and the equivalent diameter of each operating manipulator is 12 mm. An additional 9 mm-diameter channel is left for other surgical tools to pass through after all manipulators entering the port. RESULTS: The kinematics model of the robot is established, including detailed forward kinematics model and inverse kinematics solution based on geometric iteration method. The teleoperation experiment shows that the manipulator can complete the object-grasping, object-transfer and weight-lifting tasks. CONCLUSIONS: The proposed single port surgical robot design concept can also be extended to the field of natural orifice transluminal endoscopic surgical robots.

Descriptive and associated risk factors analysis of mental disorders among adolescents in Huangshi, China.

Descriptive analysis of adolescent mental disorders in Huangshi was performed to explore the gender differences, influencing factors, and abnormal illness behaviors. A total of 674 patients in Huangshi Mental Health Center from 2017 to 2022 were collected. A rising trend of mental disorders has been observed since 2018, especially during the COVID-19 pandemic. More young cases led to suicidal attempts and self-harm, which reflects the severity of mental health in adolescents. This study aims to draw the attention of government, society, families, and schools to care about adolescents, which also provides guidance and references for clinical treatment of mental disorders.

Investigation on mechanical properties deterioration of concrete subjected to freeze-thaw cycles.

Concrete structures in cold regions are usually suffer from froze and thaw action. A combined investigation of nanoindentation technique and X-ray diffraction were adopted to demonstrate the microstructure change and micromechanical properties deterioration of concrete subjected to freeze-thaw (F-T) cycles in this study. The results showed that the indentation modulus and hardness of the main compositions in mortar, such as calcium-silicate-hydrates and calcium hydroxide, both gradually decreases as the F-T cycles increase, with the greatest reduction approximate 38% after 1500 F-T cycles, while the corresponding greatest reduction of the main compositions in interfacial transition zone (ITZ) is close to 50%. In addition, the micropores in mortar and ITZ both gradually converge and connect to form larger diameter pores, and the thickness of ITZ increased rapidly from 25 to 50 µm after 1500 F-T cycles. On this basis, the effective modulus of elasticity under different F-T cycles are analyzed through Mori-Tanaka scheme with consistent variation tendency of dynamic modulus of elasticity test. Subsequently, the mechanical properties deterioration of concrete under F-T cycles is mainly attributed to the decrease of mechanical properties (such as modulus and hardness) of microscopic components, and the increase and propagation of the internal micropores especially for micropores in ITZ.

Multistage adaptive control strategy based on image contour data for autonomous endoscope navigation.

The physician burnout, poor ergonomics are hardly conducive to the sustainability and high quality of colonoscopy. In order to reduce doctors' workload and improve patients' experiences during colonoscopy, this paper proposes a multistage adaptive control approach based on image contour data to guide the autonomous navigation of endoscopes. First, a fast image preprocessing and contour extraction algorithms are designed. Second, different processing algorithms are developed according to the different contour information that can be clearly extracted to compute the endoscope control parameters. Third, when a clear contour cannot be extracted, a triple control method inspired by the turning of a novice car driver is devised to help the endoscope capture clear contours. The proposed multistage adaptive control approach is tested in an intestinal model over a variety of curved configurations and verified on the actual colonoscopy image. The results reveal the success of the strategy in both straight sections of this intestinal model and in tightly curved sections as small as 6 cm in radius of curvature. In the experiment, processing time for a single image is 20-25 ms and the accuracy of judging steering based on intestinal model pictures is 96.7%. Additionally, the average velocity reaches 3.04 cm/s in straight sections and 2.49 cm/s in curved sections respectively.

[Effects of a novel spermine oxidase inhibitor SI-4650 on proliferation and EMT of human ovarian cancer SKVO-3 cells].

Objective: To investigate the effects of SI-4650, a novel small molecule inhibitor of spermine oxidase (SMO), on the proliferation and epithelial mesenchymal transformation (EMT) of human ovarian cancer SKVO-3 cells as well as its underlying molecular mechanisms. Methods: SKVO-3 cells treated with 0 µmol/L SI-4650 were used as control group, SKVO-3 cells treated with 30, 60 µmol/L SI-4650 were used as experimental group. The effects of SI-4650 on the activity of SMO, the polyamine contents and the cellular reactive oxygen species (ROS) were detected. Cell proliferation, cell cycle and mitochondrial membrane potential change of SKVO-3 cells were tested. The effects of SI-4650 on apoptosis, migration and invasion were investigated. The effects of SI-4650 on Bax, Bcl-2, Caspase3, E-cadherin, N-cadherin, Vimentin, matrix metalloproteinase 2 ( MMP2) and MMP 9 expression levels in SKVO-3 cells were detected. Results: Comparison between blank control group and experimental groups,SI-4650 could improve the content of SI-4650 in SKVO-3 cells. SI-4650 could inhibit the activity of SMO (P＜0.01), reduce the ROS (P＜0.01)and polyamine content in SKVO-3 cells (P＜0.01). Treatment of SKVO-3 cells with SI-4650 inhibited the proliferation (the inhibition rate was 32.27% and 47.31% in experimental groups), caused S-phase cell cycle arrest (P＜0.01) and induced apoptosis (P＜0.01). The expressions of Bax and c-Caspase3 in SKVO-3 cells were increased (P＜0.01),the content of Bcl-2 was decreased (P＜0.01), and the mitochondrial membrane potential was decreased (P＜0.01), and the number of apoptotic cells was increased(31.41% and 43.51% in experimental groups). At the same time, SI-4650 could change the expression levels of EMT-related factors, increased the expression level of E-cad , decreased the expression levels of N-cad, Vimentin, MMP-2 and MMP-9, and inhibited the migration and invasion of SKVO-3 cells. Conclusion: SI-4650 can effectively inhibit proliferation, invasion and metastasis of human ovarian cancer SKVO-3 cells, and the mechanism may be related to its ability to depress the activity of SMO, interfere polyamine metabolism and induce cell cycle arrest, mitochondrial apoptosis and inhibit EMT. This study reveals potential application of SI-4650 in the treatment of ovarian cancer.

[Finite element analysis method and optimization of flexible ginger moxibustion based on Abaqus and Taguchi method].

Ginger moxibustion has the effect of regulating zang-fu organs and activating qi and blood circulation. When used, ginger paste is required to be close to human skin. Currently, the ginger box used clinically in the hospital can't meet the requirement of large area fitting human skin, and the efficacy of ginger moxibustion is significantly reduced. In this study, a flexible ginger paste box was proposed, which was composed of flexible components polydimethylsiloxane (PDMS), spring and wire netting. The large flexibility of the structure made it fit well with human skin. Finite element method was used to study the fitting degree between ginger paste box and waist soft tissue. Finite element models of flexible ginger paste box and waist soft tissue were established based on Hypermesh and Abaqus software. The equivalent contact area between the flexible ginger paste box and waist was obtained by numerical simulation under different PDMS unilateral thickness, spring wire diameter, wire netting diameter and ginger paste layer thickness. The four parameters were taken as the influencing factors, and the equivalent contact area was taken as the optimization objective. The typical value analysis and variance analysis of S/N were performed by Taguchi method, and the results showed that among the four influencing factors, the wire netting diameter had the largest influence on equivalent contact area and its contribution rate reached 41.98%. The contribution rates of PDMS unilateral thickness, spring wire diameter and ginger paste layer thickness reached 36.48%, 13.97% and 6.50%, respectively. The optimized PDMS unilateral thickness, spring wire diameter, wire netting diameter and ginger paste layer thickness were 1.5, 0.4, 0.15, 35 mm, respectively, and the equivalent contact area was 95.60 cm 2. The optimized flexible ginger paste box with great fitting performance can improve the effect of ginger moxibustion.

A Novel Inchworm-Inspired Soft Robotic Colonoscope Based on a Rubber Bellows.

Colorectal cancer is a serious threat to human health. Colonoscopy is the most effective procedure for the inspection of colorectal cancer. However, traditional colonoscopy may cause pain, which can lead to the patient's fear of colonoscopy. The use of active-motion colonoscopy robots is expected to replace traditional colonoscopy procedures for colorectal cancer screening, without causing pain to patients. This paper proposes an inchworm-like soft colonoscopy robot based on a rubber spring. The motion mechanism of the robot consists of two anchoring units and an elongation unit. The elongation unit of the robot is driven by 3 cables during contraction and by its inherent elasticity during extension. The balloon is selected as the anchoring mechanism of the robot. It has soft contact with the colon and will not damage the colon wall, which means no discomfort is caused. The elastic force test of the rubber spring shows that the elongation unit of the robot has sufficient restorative force to drive the robot to move forward and backward. The influence of the balloon's expansion size on the dexterity of the robot head is analyzed, and the functions of the balloons are expounded. The balloon can not only assist the robot in its locomotion but also assist the robot to perform a better inspection. The robot can move successfully in a horizontal, straight, and inclined isolated pig colon, showing great clinical application potential.

Design of an array of piezoresistive airflow sensors based on pressure loading mode for simultaneous detection of airflow velocity and direction.

As an irreplaceable element for obtaining airflow information in many engineering scenarios, airflow sensors have gained increasing attention across the fields of aerospace engineering, environmental engineering, sustainable energy exploitation, meteorology research, and so on. As one of the mainstream airflow sensing principles, piezoresistive airflow velocity sensors have experienced rapid growth over the years, while effective vector airflow sensors with the ability of detecting both airflow velocity and direction based on the piezoresistive principle are scarce. Here, on the basis of our developed piezoresistive airflow velocity sensors based on pressure loading mode, we design an array of these sensors and propose a corresponding explicit algorithm for simultaneous detection of airflow velocity and direction. This sensor array configuration enables an automatic recognition function of the quadrant of incoming airflow, which can significantly simplify the reverse calculation of airflow information compared with conventional vector airflow sensors. The experimental results demonstrate the decent performance of this sensor array for identifying both airflow velocity and direction. This study not only fills the gap between our developed airflow velocity sensor and the ability of detecting airflow direction but also presents a simple and universal array-based strategy for vector airflow sensing, which could be widely applied in airflow sensors based on other principles.

Cyclic drying and wetting tests on combined remediation of chromium-contaminated soil by calcium polysulfide, synthetic zeolite and cement.

Using calcium polysulfide as the reducing agent, synthetic zeolite as the adsorbent, and cement as the curing agent, the dual-index orthogonal test method was used to determine the best remediation dosage of chromium-contaminated soil. On this basis, through the dry-wet cycle test, the durability of the chromium-contaminated soil after repair is analyzed from the perspectives of unconfined compressive strength, toxic leaching concentration, quality loss, and microscopic characterization. Test results showed that the optimal ratio for the joint repair of chromium-contaminated soil was 3 times the amount of CaS5, 15% synthetic zeolite, and 20% cement. With the increase in the number of wet-dry cycles, the unconfined compressive strength of the composite preparation combined to repair chromium-contaminated soil was first increased and then reduced, and the concentration of Cr(VI) and total chromium in the leachate was first decreased and then increased. The higher the chromium content of the contaminated soil was, the lower the unconfined compressive strength, and the higher the leaching concentration of Cr(VI) and total chromium were. With the increase in cycle times, the cumulative mass-loss rate of composite preparations for repairing chromium-contaminated soil gradually increased, and the higher the chromium content was, the higher the cumulative mass-loss rate, which was less than 2%, reflecting the combination of composite preparations for repairing chromium-contaminated soil to have good durability. Microscopic and macroscopic results are consistent with each other.

Preparation of Cemented Oil Shale Residue-Steel Slag-Ground Granulated Blast Furnace Slag Backfill and Its Environmental Impact.

A new environmentally friendly cemented oil shale residue-steel slag-ground granulated blast furnace slag backfill (COSGB) was prepared using oil shale residue (OSR), steel slag (SS) and ground granulated blast furnace slag (GGBS) as constituent materials. Based on univariate analysis and the Box-Behnken design (BBD) response surface method, the three responses of the 28 days unconfined compressive strength (UCS), slump and cost were used to optimize the mix ratio. Using a combination of scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP), the reaction products, microscopic morphology and pore structure of the specimens with the optimal mix ratio at different curing ages were analyzed. The influence of heavy metal ions from the raw materials and the COSGB mixtures on the groundwater environment was studied by leaching tests. The research demonstrates that the optimal mix ratio is GGBS mixing amount 4.85%, mass ratio of SS to OSR 0.82, and solid mass concentration 67.69%. At shorter curing age, the hydration products are mainly calcium alumino silicate hydrate (C-A-S-H) and calcium silicate hydrate (C-S-H) gels. With the increase of curing age, ettringite (AFt) and C-S-H gels become the main source of the UCS. Meanwhile, the porosity of the filler decreases continuously. The leaching concentration of heavy metal ions from the COSGB mixtures is all lower than the leaching concentration of raw materials and meet the requirements of the Chinese groundwater quality standard (GB/T 14848-2017). Therefore, this new COSGB cannot pollute the groundwater environment and meets backfill requirements. The proposed technology is a reliable and environmentally friendly alternative for recycling OSR and SS while simultaneously supporting cemented paste backfill (CPB).

[Distribution Characteristics of Microplastics in Ice Sheets and Its Response to Salinity and Chlorophyll a in the Lake Wuliangsuhai].

There are sparse reports on the distribution of microplastics in the ice sheets of freshwater lakes. In this study, the abundance, color, shape, and species of microplastics in the ice sheet of Lake Wuliangsuhai were characterized using field sampling and microscope observations. Fourier-transform infrared spectroscopy (FTIR) and correlation analysis were used to examine the distribution of microplastics contained in the lake and its relationships with salinity and chlorophyll a. The results show that the average abundance of microplastics in the Lake Wuliangsuhai ice sheet is 56.75-141 n·L-1, which is approximately 10-100 times higher than in the surface water of the Lake Wuliangsuhai. Fibers were the most common type of microplastics followed by fragments. Overall abundance showed a decreasing trend in the downstream horizontal direction and was positively correlated with salinity in the vertical direction. The abundance of microplastic in the surface ice and bottom ice was greater than in the middle of the ice and near bottom of the ice. There was no correlation between the abundance of microplastic and the concentration of chlorophyll a. In addition, due to the capturing effect of the ice, microplastic particles are temporarily stored in the ice sheet in winter, which are released into water in spring. This study provides baseline information to inform microplastic pollution control measures in Lake Wuliangsuhai.

Efficacy and Safety of Ningmitai Capsule in Patients With Chronic Prostatitis/Chronic Pelvic Pain Syndrome: A Multicenter, Randomized, Double-blind, Placebo-controlled Trial.

OBJECTIVE: To validate the efficacy and safety of Ningmitai capsule (NMT) in the patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled trial in 120 men with CP/CPPS to evaluate the efficacy and safety of NMT. Participants were randomly assigned (1:1) to NMT or placebo treatment for 4 weeks at 3 centres. The patients were evaluated by the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) at baseline, the end of 2 and 4 weeks of treatment. The primary endpoints were the changes of the NIH-CPSI pain scores from baseline to the end of 2 and 4 weeks of the treatment. The secondary endpoints include the changes of the NIH-CPSI total scores, urinary symptoms scores and the quality of life (QoL) as well as the responder rate. RESULTS: After 2 and 4 weeks of treatment, the mean decreases of the NIH-CPSI pain scores, total scores and QoL in the NMT group were all significantly superior to those in the placebo group. The responder rate was significantly higher in the NMT group than that in the placebo group at both 2 and 4 weeks. No adverse events were reported during the treatment. CONCLUSION: NMT could significantly improve the pain symptoms and QoL in the patients with CP/CPPS as early as in 2 weeks, and the efficacy enhanced at the end of the 4-week treatment. The safety of NMT was confirmed in this trial.

Preparation, characterization serpentine-loaded hydroxyapatite and its simultaneous removal performance for fluoride, iron and manganese.

Aiming at the problem of excessive fluorine, iron, and manganese pollution in groundwater in mining areas, a serpentine-loaded hydroxyapatite (Srp/HAP) composite adsorbent was prepared by wet chemical coprecipitation. The preparation conditions of the Srp/HAP composite adsorbent were explored, Srp/HAP was microscopically characterized, and the adsorption performance and adsorption mechanism of the Srp/HAP composite adsorbent for F-, Fe2+ and Mn2+ were analyzed. The results showed that the optimal preparation conditions for the composite particles were as follows: solid-liquid ratio of Srp to calcium nitrate solution 20%, aging time 20 h, calcination temperature 180 °C, and calcination time 90 min. Compact Srp/HAP composite adsorbent particles were successfully prepared, and both the lamellar crimp structure of the Srp surface and the problem of HAP surface agglomeration were resolved. After loading, the specific surface area and pore volume of the particles significantly increased, and the surface pore structure improved, which is conducive to the simultaneous adsorption and removal of fluorine, iron and manganese. The optimal reaction conditions for Srp/HAP treatment of composite water samples with F-, Fe2+ and Mn2+ mass concentrations of 5 mg L-1, 20 mg L-1 and 5 mg L-1, respectively, are as follows: dosage of Srp/HAP 3 g L-1, pH 7, temperature 35 °C, and reaction time 150 min. Under these conditions, the removal rates of F-, Fe2+ and Mn2+ were 98.6%, 99.9% and 99.8%, respectively. The quasi-second-order kinetic model and Langmuir isothermal adsorption model described the adsorption process of F-, Fe2+ and Mn2+ by the composite particles well. The adsorption process includes both surface physical adsorption and chemical adsorption. Chemical adsorption is mainly characterized by ion exchange and surface complexation. The Srp/HAP composite particles can be used as an excellent adsorbent for the treatment of groundwater containing fluorine, iron and manganese ions in mining areas.

Nanopore Formation and Structural Changes in Black Shale During the Initial Weathering Stage: A Longmaxi Formation Profile in Northwestern Hunan, China.

Understanding the controls on composition changes and porosity evolution in the critical zone of shale remains a major challenge. The aim of the present study is to develop a model of the changes in mineral compositions, chemical compositions and nanopore formation in shale during the initial weathering stage. To understand these processes, we selected a Silurian shale profile rich in pyrite and organic matter located in South China. Based on X-ray diffraction (XRD) and bulk elemental data, the variations in mineralogical and chemical compositions with depth were studied. To characterize the full pore size spectrum and to gain insight into the nature of secondary pores and their relationship with weathering, nuclear magnetic resonance (NMR) measurements and petrographic observations were combined with scanning electron microscopy (SEM) imaging. The results show that Al and K are enriched slightly, while Ca and Na are depleted in the upper part of the weathering profile. Si, Mn and Ti are relatively stable from the bottom to the top of the profile. Quartz, feldspar, mica, illite and chlorite are the main minerals in the parent rock, and they are relatively stable along the profile. The rock density gradually decreases from 2.6 g/cm³ to 2.1 g/cm³ from the bottom to the top, and the color of the shales changes from black to grayish yellow, but no secondary minerals are detected. The chemical weathering of black shale is dominated by the oxidation of pyrite and organic matter, giving rise to color variation and nanopore formation. The increase in interparticle pores at the nanometer-micron scale is initiated by the dissolution of easily weathered components such as organic matter and pyrite. The removal of clay minerals and tiny particles by groundwater seepage may be the main cause of porosity enhancement during the initial weathering stage. This study suggests that nanoporosity may play an important role in the process of fluid-rock interaction within black shale during the initial weathering stage.