Response surface optimization of sludge dewatering process: synergistic enhancement by ultrasonic, chitosan and sludge-based biochar.

Due to the colloidal stability, the high compressibility and the high hydration of extracellular polymeric substances (EPS), it is difficult to efficiently dehydrate sludge. In order to enhance sludge dewatering, the process of ultrasonic (US) cracking, chitosan (CTS) re-flocculation and sludge-based biochar (SBB) skeleton adsorption of water-holding substances to regulate sludge dewaterability was proposed. Based on the response surface method, the prediction model of the specific resistance to filtration (SRF) and sludge cake moisture content (MC) was established. The US cracking time and the dosage of CTS and SBB were optimized. The results showed that the optimal parameters of the three were 5.08 s, 10.1 mg/g dry solids (DS) and 0.477 g/g DS, respectively. Meantime, the SRF and MC were 5.4125 × 1011 m/kg and 76.8123%, which significantly improved the sludge dewaterability. According to the variance analysis, it is found that the fitting degree of SRF and MC model is good, which also confirms that there is significant interaction and synergy between US, CTS and SBB, and the contribution of CTS and SBB is greater. Moreover, the process significantly improves the sludge's calorific value and makes its combustion more durable.

Mechanistic study of the effect of potassium ferrate and straw fiber on the enhancement of strength in cement-based solidified municipal sludge.

The high content of organic matter in sludge is the primary reason for the poor solidifying effect and excessive dosage of the cement base. In this study, potassium ferrate and straw fiber are utilized to synergistically enhance the solidifying effect of the cement and elaborate the strength mechanisms. Among them, potassium ferrate was selected to oxidize and crack the structure of organic matter in sludge and consume part of organic matter; straw fiber was used as an adsorption material to absorb some of the organic material and reduce its interference with the cement hydration reaction; the skeleton function of straw fiber in solidified sludge was used to improve the final solidified sludge strength. It is shown that the presence of these two additives significantly improved the cement solidification strength and reduced the moisture content of the solidified body. Moreover, the moisture content and strength followed an obvious linear relationship (adjusted R2 = 0.92), with the strength increasing as the moisture content decreased. After pretreatment with potassium ferrate, the free water content in the dewatered sludge increased by 4.5%, which was conducive to the adequate hydration reaction with cement. The analysis using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), and mercury intrusion porosimetry (MIP) revealed potassium ferrate synergizes with straw fibers to promote the production of hemihydrate gypsum and gismondine. However, hemihydrate gypsum, calcium carbonate, and gismondine resulted in structural swelling, which was confirmed by the microscopic morphology and pore structure analysis. However, the adverse effects due to swelling were offset by the increase in strength brought by the above crystalline substances.

Degree of protection provided by poverty alleviation policies for the middle-aged and older in China: evaluation of effectiveness of medical insurance system tools and vulnerable target recognition.

BACKGROUND: China's medical insurance schemes and poverty alleviation policy at this stage have achieved population-wide coverage and the system's universal function. At the late stage of the elimination of absolute poverty task, how to further exert the poverty alleviation function of the medical insurance schemes has become an important agenda for targeted poverty alleviation. To analyse the risk of catastrophic health expenditure (CHE) occurrence in middle-aged and older adults with vulnerability characteristics from the perspectives of social, regional, disease, health service utilization and medical insurance schemes. METHODS: We used data from the 2018 China Health and Retirement Longitudinal Study (CHARLS) database and came up with 9190 samples. The method for calculating the CHE was adopted from WHO. Logistic regression was used to determine the different characteristics of middle-aged and older adults with a high probability of incurring CHE. RESULTS: The overall regional poverty rate and incidence of CHE were similar in the east, central and west, but with significant differences among provinces. The population insured by the urban and rural integrated medical insurance (URRMI) had the highest incidence of CHE (21.17%) and health expenditure burden (22.77%) among the insured population. Integration of Medicare as a medical insurance scheme with broader benefit coverage did not have a significant effect on the incidence of CHE in middle-aged and older people with vulnerability characteristics. CONCLUSIONS: Based on the perspective of Medicare improvement, we conducted an in-depth exploration of the synergistic effect of medical insurance and the poverty alleviation system in reducing poverty, and we hope that through comprehensive strategic adjustments and multidimensional system cooperation, we can lift the vulnerable middle-aged and older adults out of poverty.

Exploring the role of potassium ferrate and straw fiber in enhancing the strength of cement-based solidified municipal sludge.

The effect of potassium ferrate (PF) and straw fiber (SF) on the strength of cement-based solidified municipal sludge, including the influence of reducing the organic matter in the sludge on the efficiency of the hydration of the cement, was studied. Single-factor tests, orthogonal tests, and linear weighted optimization methods were used to obtain suitable ratios to meet practical requirements, and then SEM and XRD analyses were used to explore the solidification mechanism. The results showed that PF and SF had significant influence on the strength, with SF having the greatest influence and the strength increasing with the amount of both admixtures, and cement had no significant influence on the strength. After linear weighting optimization, the ideal dosage was found to be 20% cement, 20% PF, and 5% SF, which produced a solidified sludge that had an strength of 126.87 kPa, far higher than the 50 kPa required to qualify for disposal in landfills. Analysis of the mineral content and microstructure showed that PF and SF could promote cement hydration and produce more hydration products, and the density of the optimized sample was much higher than that of the raw sludge and a sludge sample mixed with 20% cement alone.

SIRT1 exerts anti-hypertensive effect via FOXO1 activation in the rostral ventrolateral medulla.

The rostral ventrolateral medulla (RVLM) is a pivotal region in the central regulation of blood pressure (BP). It has been documented that silent information regulator 2 homolog 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD+)-dependent multifunctional transcription regulatory factor, has many cardiovascular protective effects. However, the role and significance of SIRT1 in the central regulation of cardiovascular activity, especially in RVLM, remains unknown. Therefore, the aim of this study was to explore the role and underlying mechanism of SIRT1 in the central regulation of cardiovascular activity in hypertension. Spontaneously hypertensive rats (SHRs) were given resveratrol (RSV) via intracerebroventricular (ICV) infusion or injected with SIRT1-overexpressing lentiviral vectors into the RVLM. In vitro experiments, angiotensin II (Ang II)-induced rat pheochromocytoma cell line (PC12 cells) were transfected with forkhead box protein O1 (FOXO1) small interfering RNA (siRNA) before treatment with RSV. Our results showed that SIRT1 activation with RSV or overexpression in the RVLM significantly decreased BP and sympathetic outflow of SHRs. Furthermore, SIRT1 overexpression in the RVLM significantly decreased reactive oxygen species (ROS) production and facilitated the forkhead box protein O1 (FOXO1) activation, accompanied by upregulation of the ROS-detoxifying enzyme superoxide dismutases 1 (SOD1) in the RVLM of SHRs. In PC12 cells, it was found that Ang II could induce oxidative stress and downregulate the SIRT1-FOXO1-SOD1 signaling pathway, which indicated that the suppressed expression of SIRT1 in the RVLM of SHRs might relate to the elevated central Ang II level. Furthermore, the enhanced oxidative stress and decreased SIRT1-FOXO1-SOD1 axis induced by Ang II were restored by treatment with RSV. However, these favorable effects mediated by SIRT1 activation were blocked by FOXO1 knockdown. Based on these findings, we concluded that SIRT1 activation or overexpression in the RVLM exerts anti-hypertensive effect through reducing oxidative stress via SIRT1-FOXO1-SOD1 signaling pathway, which providing a new target for the prevention and intervention of hypertension.

Efficiency and mechanism of reducing ammonia volatilization in alkaline farmland soil using Bacillus amyloliquefaciens biofertilizer.

Ammonia volatilization from the farmland caused by the application of synthetic nitrogen fertilizer is the most important source of anthropogenic ammonia emissions. Biofertilizer application has been considered as an alternative option for agriculture sustainability and soil improvement. In this study, field trials were carried out to investigate the efficiency of Bacillus amyloliquefaciens (BA) biofertilizer on alleviating ammonia volatilization in alkaline farmland soil and increasing crop yield and nitrogen utilization. Potential response mechanisms were investigated from soil enzyme, nitrogen cycle function genes and microbial community levels. Compared with conventional fertilization, BA biofertilizer application reduced the ammonia volatilization by 68%, increased the crop yield and nitrogen recovery by 19% and 19%, respectively. Soil enzyme activity analysis showed that BA biofertilizer inhibited the urease activity and enhanced the potential ammonia oxidation (PAO). In addition, BA biofertilizer application also increased the bacterial amoA gene abundance, while decreased the ureC gene abundance. BA biofertilizer also significantly altered the community structure and composition, and especially raised the abundance of ammonia oxidation bacteria (AOB), while no changes were observed in abundance of nitrite oxidation bacteria (NOB). Briefly, BA biofertilizer was approved to reduce the transformation of fertilizer nitrogen to NH4+-N, simultaneously accelerating NH4+-N into the nitrification process, thus decreasing the NH4+-N content remained in alkaline soil and consequently alleviating the ammonia volatilization. Thus, these results suggested that the application of BA biofertilizer is a feasible strategy to improve crop yields and reduce agricultural ammonia emissions.

[Bacillus amyloliquefaciens Biofertilizer Mitigating Soil Ammonia Volatilization].

In this study, we investigated the effectiveness and microbial mechanism of Bacillus amyloliquefaciens biofertilizer on reducing ammonia volatilization in farmland soil. Pot experiments were carried out to explore the effects of B. amyloliquefaciens biofertilizer (BB) and chemical fertilizer on soil ammonia volatilization, crop yield and quality, and soil microbial community. Four fertilization strategies were tested, namely no fertilizer (CK), 100% chemical fertilizer (C), 50% BB and 50% chemical fertilizer (B1), and 100% BB (B2). The dynamic flow-through chamber method was used to determine the soil ammonia volatilization flux after fertilization. The soil bacterial community during the peak period of ammonia volatilization was analyzed using 16S rDNA high-throughput sequencing. The results showed that the amount of ammonia volatilization in B1 and B2 decreased by 79.5% and 84.8%, respectively, as compared with treatment C. B2 had the lowest nitrate content and the highest yield; the yield of B2 increased by 50.5% and 12.3% as compared to that of CK and C, respectively. B1 had the highest content of vitamin C, which was 67.6 mg ·kg-1. The application of BB improved the diversity and richness of soil bacterial community, especially the relative abundance of Bacillus and Nitrospira. This shows that BB plays an important role in preventing air pollution and improving nitrogen utilization.

A cross-sectional study on serum measles antibody levels of a healthy population in southwest China.

This study aimed to investigate measles antibody level and its associated factors in a healthy Chinese population, so as to provide evidence to measles prevention and control measures in the future.We conducted a cross-sectional survey by using probability proportionate to size sampling (PPS) among a healthy population aged 8 months to 45 years. Information on measles vaccination status was obtained from the vaccination certificates. Serum measles IgG antibody was detected by enzyme-linked immunosorbent assay. Multivariate logistic and linear regression models were used to analysis the associated factors of measles antibody.Of the 663 study subjects, the positive rate, protective rate, and geometric mean concentration (GMC) of measles antibodies were 92.76%, 77.53%, 1612.55 mIU/ml, respectively. The antibody concentration was higher in Han ethnical majority than in Hui minority. The positive rate, protective rate and concentration of antibodies in different age groups and regions were clearly disparate. Age, area, and measles-containing vaccine (MCV) immunization history were the prominent influencing factors of antibody positive rate and protective rate. Ethnicity, age, area, and MVC immunization history were the influencing factors of antibody concentration.Our major findings suggest that, children in rural China, especially in impoverished mountainous regions, were more likely to suffer from delays in measles vaccination. Various measures in optimizing vaccination practices should be implemented in order to prevent possible measles epidemic, even outbreak in these regions.

Henoch-Schönlein purpura nephritis associated with monoclonal gammopathy of renal significance: a case report.

Monoclonal gammopathy of renal significance (MGRS) can present with different morphologic features and lead to kidney failure. The Henoch-Schönlein purpura nephritis (HSPN) that cannot be relieved by treatment with glucocorticoid and immunosuppressive agents suggests the presence of monoclonal gammopathy in adult patients. The present study reports on a single case of HSPN associated with IgA-κMGRS. The patient who suffered from recurrent skin purpura for 6 months and nephrotic syndrome for 2 months was admitted to our hospital. Bone marrow biopsy showed monoclonal gammopathy of undetermined significance. Kidney biopsy indicated a Henoch-Schönlein purpura nephritis (HSPN, ISKDC classified as type III) with positive staining with κ-light chain in the glomeruli and renal tubular epithelial cells. Furthermore, skin biopsy showed leukocytoclastic vasculitis and negative staining for Congo red and light chain. Given both the renal and cutaneous involvement, the patient was considered to have HSPN associated with IgA-κMGRS. The patient experienced an exacerbation in his purpura-like lesions and clinical status after treatment with glucocorticoid and immunosuppressive agents. Consequently, the patient was put on a regimen that included dexamethasone (20 mg on the 1st, 4th, 8th, and 11th days of each month, iv) and bortezomib (2.4 mg on the 1st, 4th, 8th, and 11th days of each month, iv). Eight weeks after treatment, he had complete resolution of his cutaneous purpura and his biochemical parameters improved. The latent presence of MGRS in cases of HSPN should be considered in adult patients. Increased cognizance and correct treatment options could improve patient outcomes.

Analysis on spatial-temporal distribution characteristics of smear positive pulmonary tuberculosis in China, 2004-2015.

BACKGROUND: In China, tuberculosis (TB) is still a major infectious disease threatening people's health. Smear positive pulmonary TB is one of the most common infectious forms of TB and it might easily cause the outbreak in some areas. With a better understanding of the spatial-temporal variations of smear positive PTB, we would reach the targets for TB prevention and controlling, identify high-risk areas and periods. Thus, the aim of this study was to investigate the spatial-temporal variations of smear positive PTB. METHODS: Provincial level data of reported smear positive PTB monthly cases and incidence from January 2004 to December 2015 were obtained from the National Scientific Data Sharing Platform for Population and Health of China. Purely spatial-temporal descriptive analysis was used to characterize the distribution patterns of smear positive PTB. The global spatial auto-correlation statistics (Moran's I) and the local indicators of spatial association (LISA) were conducted to identify the spatial auto-correlation and high risk areas of smear positive PTB cases. Furthermore, the space-time scan statistic was adopted to detect the spatial-temporal clusters in different periods. RESULTS: A total of 4,711,571 smear positive PTB cases were notified in China with an average annual incidence of 29.59/100,000. The proportion of male in different age groups were obviously higher than that of women. The largest number of cases was reported in the 20-24 years age group. Time-series analysis indicated that monthly incidence appeared a clearly seasonality and periodicity, which the seasonal peaks occurred in January and March. Smear positive PTB cases had a positive global spatial auto-correlation in 2013-2015 (Moran's I=0.186, P=0.046). Spatial clusters were identified in four periods, located in the different regions. The time period of 2004-2006, the most likely spatial-temporal cluster (RR=1.69, P<0.001) was mainly located in Hubei, Hunan, Jiangxi and Anhui of central China, clustering in the time frame from January 2005 to June 2006. During 2007-2009, the most likely spatial-temporal cluster (RR=5.65, P<0.001) was located in Guizhou, clustering in the time frame from January to December 2009. The spatial-temporal clustering in the years 2010-2012 showed the most likely cluster (RR=1.44, P<0.001) was distributed in Anhui, Hunan, Hubei, Jiangxi and Guangdong with the time frame from January 2010 to June 2011. During 2013-2015, the most likely cluster (RR=1.86, P<0.001) was detected in Hunan, Hubei, Jiangxi and Guangdong from February 2013 to June 2014. CONCLUSIONS: This study identified the spatial-temporal patterns of smear positive PTB in China and demonstrated the capability and utility of the spatial-temporal approach in epidemiology. The results of this study would contribute to estimating the high risk periods and areas, and to providing more useful information for policy-making.

Henoch-Schönlein purpura nephritis associated with monoclonal gammopathy of renal significance: a case report

Monoclonal gammopathy of renal significance (MGRS) can present with different morphologic features and lead to kidney failure. The Henoch-Schönlein purpura nephritis (HSPN) that cannot be relieved by treatment with glucocorticoid and immunosuppressive agents suggests the presence of monoclonal gammopathy in adult patients. The present study reports on a single case of HSPN associated with IgA-κMGRS. The patient who suffered from recurrent skin purpura for 6 months and nephrotic syndrome for 2 months was admitted to our hospital. Bone marrow biopsy showed monoclonal gammopathy of undetermined significance. Kidney biopsy indicated a Henoch-Schönlein purpura nephritis (HSPN, ISKDC classified as type III) with positive staining with κ-light chain in the glomeruli and renal tubular epithelial cells. Furthermore, skin biopsy showed leukocytoclastic vasculitis and negative staining for Congo red and light chain. Given both the renal and cutaneous involvement, the patient was considered to have HSPN associated with IgA-κMGRS. The patient experienced an exacerbation in his purpura-like lesions and clinical status after treatment with glucocorticoid and immunosuppressive agents. Consequently, the patient was put on a regimen that included dexamethasone (20 mg on the 1st, 4th, 8th, and 11th days of each month, iv) and bortezomib (2.4 mg on the 1st, 4th, 8th, and 11th days of each month, iv). Eight weeks after treatment, he had complete resolution of his cutaneous purpura and his biochemical parameters improved. The latent presence of MGRS in cases of HSPN should be considered in adult patients. Increased cognizance and correct treatment options could improve patient outcomes.

Synthesis of KMnO4-treated magnetic graphene oxide nanocomposite (Fe3O4@GO/MnO x ) and its application for removing of Cu2+ ions from aqueous solution.

A magnetic KMnO4-treated graphene-oxide-based nanocomposite, Fe3O4@GO/MnO x , was synthesized through a facile hydrothermal technique. The properties of the Fe3O4@GO/MnO x nanocomposite were characterized by SEM, XRD and FTIR. Batch experiments showed that the maximum adsorption capacity calculated by the Langmuir model for Cu2+ was 62.65 mg g-1 at T = 303.15 K. Kinetics and XPS analysis also revealed that the mechanism of Cu2+ removal was mainly a chemical adsorption process involving both the MnO x particles and oxygen functional groups. The prepared Fe3O4@GO/MnO x was found to be an ideal adsorbent for the removal of Cu2+ ions due to the MnO x particle coating, and was easily separated using a magnetic field after utilization. Reusability studies imply that Fe3O4@GO/MnO x is a suitable material for heavy metal ion removal from aqueous solutions in real applications.

Exercise Training Improves the Altered Renin-Angiotensin System in the Rostral Ventrolateral Medulla of Hypertensive Rats.

The imbalance between angiotensin II (Ang II) and angiotensin 1-7 (Ang 1-7) in the brain has been reported to contribute to cardiovascular dysfunction in hypertension. Exercise training (ExT) is beneficial to hypertension and the mechanism is unclear. This study was aimed to determine if ExT improves hypertension via adjusting renin angiotensin system in cardiovascular centers including the rostral ventrolateral medulla (RVLM). Spontaneously hypertensive rats (SHR, 8 weeks old) were subjected to low-intensity ExT or kept sedentary (Sed) for 12 weeks. Blood pressure elevation coupled with increase in age was significantly decreased in SHR received ExT compared with Sed. The results in vivo showed that ExT significantly reduced or increased the cardiovascular responses to central application of sarthran (antagonist of Ang II) or A779 (antagonist of Ang 1-7), respectively. The protein expression of the Ang II acting receptor AT1R and the Ang 1-7 acting receptor Mas in the RVLM was significantly reduced and elevated in SHR following ExT, respectively. Moreover, production of reactive oxygen species in the RVLM was significantly decreased in SHR following ExT. The current data suggest that ExT improves hypertension via improving the balance of Ang II and Ang 1-7 and antioxidative stress at the level of RVLM.

LIPUS promotes spinal fusion coupling proliferation of type H microvessels in bone.

Low-intensity pulsed ultrasound (LIPUS) has been found to accelerate spinal fusion. Type H microvessels are found in close relation with bone development. We analyzed the role of type H vessels in rat spinal fusion model intervened by LIPUS. It was found LIPUS could significantly accelerate bone fusion rate and enlarge bone callus. Osteoblasts were specifically located on the bone meshwork of the allograft, and were surrounded by type H microvessels. LIPUS could significantly increase the quantity of osteoblasts during spine fusion, which process was coupled with elevated angiogenesis of type H microvessels. Our results suggest that LIPUS may be a noninvasive adjuvant treatment modality in spinal fusion for clinical use. The treatment is recommended for usage for at least one month.

Centrally acting drug moxonidine decreases reactive oxygen species via inactivation of the phosphoinositide-3 kinase signaling in the rostral ventrolateral medulla in hypertensive rats.

OBJECTIVE: Centrally acting antihypertensive action of moxonidine is a result of activation of Imidazoline-1 receptor (I1R) in the rostral ventrolateral medulla (RVLM). Hypertension shows an increase in reactive oxygen species (ROS) in the RVLM. The present objective was to determine the phosphoinositide-3 kinase (PI3K) signaling pathway involved in the effect of moxonidine on ROS generation in the RVLM of spontaneously hypertensive rat (SHR). METHODS: Wistar-Kyoto rats and SHR received intracisternal infusion (2 weeks) of tested agents which were subjected to subsequent experiments. In-situ ROS in the RVLM was evaluated by the oxidative fluorescence dye. Western blot and PCR analysis were performed to detect the expression levels of PI3K signaling pathway. Lentivirus was injected bilaterally into the RVLM for silencing PI3K signaling. RESULTS: ROS production in the RVLM was dose-dependently reduced in SHRs treated with infusion of moxonidine (20 nmol/day), which was prevented by the I1R antagonist efaroxan but not by the α2-adrenoceptor antagonist yohimbine. Moxonidine pretreatment significantly blunted cardiovascular sensitivity to injection of tempol (5 nmol) or angiotensin II (10 pmol) into the RVLM in SHR. Expression levels of PI3K/Akt, nuclear factor kappa-B (NFκB), NADPHase (NOX4), and angiotensin type I receptor (AT1R) in the RVLM were markedly decreased in SHR treated with moxonidine. Infection of lentivirus containing PI3K shRNA in the RVLM effectively prevented effects of moxonidine on cardiovascular activity and expression levels of Akt, NFκB, NOX4, and AT1R. CONCLUSION: The centrally antihypertensive drug moxonidine decreases ROS production in the RVLM through inactivation of the PI3K/Akt signaling pathway in hypertension.

The PI3K signaling-mediated nitric oxide contributes to cardiovascular effects of angiotensin-(1-7) in the nucleus tractus solitarii of rats.

Angiotensin-1-7 [Ang-(1-7)], acting via the Mas receptor in the central nervous system, is involved in the regulation of cardiovascular activity. Nitric oxide (NO) is implicated as an important modulator in the nucleus tractus solitarii (NTS), a key region involved in control of cardiovascular activity. The aim of the present study was to determine the role of phosphatidylinositol 3-kinase (PI3K) signaling in mediating the effect of Ang-(1-7) on NO generation in the NTS. In Sprague-Dawley rats, acute injection of Ang-(1-7) into the NTS significantly increased NO generation and neuronal/endothelial NO synthase (n/eNOS) activity, which were abolished by the selective Mas receptor antagonist d-Alanine-[Ang-(1-7)] (A-779), the PI3K inhibitor LY294002, or the Akt inhibitor triciribine (TCN). Western blotting analysis further demonstrated that Ang-(1-7) significantly increased levels of Akt/NOS phosphorylation in the NTS, and Ang-(1-7)-induced e/nNOS phosphorylation was antagonized by LY294002 or TCN. Furthermore, gene knockdown of PI3K by lentivirus containing small hairpin RNA in the NTS prevented the Ang-(1-7)-induced increases in NOS/Akt phosphorylation and NO production. The physiological (in vivo) experiments showed that pretreatment with the NOS inhibitor l-NAME, LY294002, or TCN abolished the decreases in blood pressure, heart rate, and renal sympathetic nerve activity induced by Ang-(1-7) injected into the NTS. Our findings suggest that nitric oxide release meditated by the Mas-PI3K-NOS signaling pathway is involved in the cardiovascular effects of Ang-(1-7) in the NTS.

[Crosslinking sodium hyaluronate gel with different ratio of molecular weight for subcutaneous injection: animal experimental study and clinical trials subcutaneous injection].

OBJECTIVE: To investigate the biocompatibility and degradation rate of crosslinking sodium hyaluronate gel with different ratio of molecular weight, so as to choose the effective, safe and totally degraded hyaluronate gel for aesthetic injection. METHODS: (1) Compound colloid was formed by cross-linking the divinyl sulphone and sodium hyaluronate with different molecular weight (4 x 10(5), 8 x 10(5), 10 x 10(5), 12 x 10(5)). (2) Healthy level KM mice was randomly divided into two groups to receive hyaluronic acid gel or liquid injection. Each group was subdivided into three subgroup to receive hyaluronic acid with different molecular weight. The biocompatibility and degradation rate, of hyaluronate were observed at 7, 90, 180 days after injection. At the same time, different molecular weight of sodium hyaluronate gel is sealed or exposed respectively under the low temperature preservation to observe its natural degradation rate. (3) The most stable colloid was selected as aesthetic injector for volunteers to observe the aesthetic effect. RESULTS: The sodium hyaluronate gel with molecular of 4 x 10(5) was completely degraded 90 days later. The sodium hyaluronate gel with molecular of 8 x 10(5) was completely degraded 180 days later. The sodium hyaluronate gel with molecular of 10 x 10(5) was degraded to 90.0% after 180 days. The sodium hyaluronate liquid can be degraded completely within 7 days. The colloid could be kept for at least 12 months when sealed under low temperature, but was totally degraded when exposed for I d. Sodium hyaluronate gel with molecular 10 x 10(5) was confirmed to be kept for at least 6 months in animal experiment and clinical trials. CONCLUSIONS: Under the same condition of material ratio, the higher the molecular weight is, the lower the degradation rate is. But the liquidity of gel is not good for injection when molecular weight is too large. It suggests that Sodium hyaluronate gel with molecular 10 x 10(5) maybe the best choice in cosmetic injections.

Investigation of medical waste management in Gansu Province, China.

Medical waste is a special category of waste with potential health and environment risks. The present study aimed to explore the current status of medical waste management in western China. Seventy-four healthcare facilities were selected to assess the general status of medical waste management based upon a designed questionnaire survey. The surveyed results showed that the quantities of average medical waste generation were 0.79, 0.59 and 0.61 kg bed(-1) day(-1) in tertiary, secondary and primary hospitals, respectively. The incomplete segregation of domestic and medical waste generated a higher quantity of medical waste in primary hospitals (0.61 kg bed(-1) day(-1)) than that in secondary hospitals. Furthermore, the effective implementation of the medical waste management system depended on national regulations, occupational safety, internal policies and administration and the qualifications and competence of the directors of the waste management department in the healthcare facilities. Therefore, sufficient training programmes and protective measures should be provided by healthcare facilities to all relevant personnel and adequate financial support and effective administrative monitoring should be performed by local authorities.