An atmospheric water harvesting system based on the "Optimal Harvesting Window" design for worldwide water production.

Atmospheric water harvesting (AWH) is a promising solution to the water shortage problem. Current sorption-based AWH (SAWH) systems seldom obtain both wide climatic adaptability and high energy efficiency due to the lack of thermodynamic optimization. To achieve the ideal harvesting circulation in SAWH systems, the "optimal harvesting window" (OHW) design based on thermodynamic analysis was first proposed and validated by our prototype. The "OHW" theory indicates the water production rate and energy efficiency could be improved by properly reducing the adsorption temperature. As the humidity increases, the optimal adsorption temperature should be closer to the dew point of the environment. Experimental results revealed that, loaded with 3 kg widely adopted silica gel, the daily water production could reach 5.76-17.64 L/d with ultrahigh energy efficiency of 0.46-1.5 L/kWh. This prototype could also achieve optimal performance in wide climatic conditions in terms of 13-35 °C and 18%-72% RH. Lastly, the performance of photovoltaic (PV)-driven SAWH was evaluated. Results showed that a 1 m2 PV panel could generate 0.66-2 L water per day in Shanghai throughout the year, the highest in opening literature. Notably, this work introduces a promising concept that can help achieve large-scale, ultra-fast, energy-efficient AWH worldwide.

Pathways to Energy-efficient Water Production from the Atmosphere.

Atmospheric water harvesting (AWH) provides a fascinating chance to facilitate a sustainable water supply, which obtains considerable attention recently. However, ignoring the energy efficiency of AWH leads to high energy consumption in current prototypes (ca. 101 to 102  MJ kg-1 ), misfitting with the high-strung and complicated water-energy nexus. In this perspective, a robust evaluation of existing AWHs is conducted and a detailed way to high-efficiency AWH is paved. The results suggest that using cooling-assisted adsorption will weaken the bounds of climate to sorbent selections and have the potential to improve efficiency by more than 50%. For device design, the authors deeply elucidate how to perfect heat/mass transfer to narrow the gap between lab and practices. Reducing heat loss, recovering heat and structured sorbent are the main paths to improve efficiency on the device scale, which is more significant for a large-scale AWH. Besides efficiency, the techno-economic evaluation reveals that developing a cost-effective AWH is also crucial for sustainability, which can be contributed by green synthesis routes and biomass-based sorbents. These analyses provide a uniform platform to guide the next-generation AWH to mitigate the global water crisis.

Dynamics of Detection of Anti-SARS-CoV-2 IgG/IgM and SARS-CoV-2 RNA in Respiratory Tract Specimens in 48 COVID-19 Patients.

BACKGROUND: The rapid spread of pneumonia caused by SARS-CoV-2 has seriously threatened people. In this study, we detected the expression of anti-SARS-CoV-2 IgG/IgM and respiratory tract SARS-CoV-2 RNA in patients with COVID-19 and explored the correlation and clinical significance between SARS-CoV-2 antibody and respiratory SARS-CoV-2 RNA. METHODS: From March 5, 2020 to April 28, 2020, 48 cases with COVID-19 diagnosed in Beijing Xiaotangshan Hospital were enrolled. SARS-CoV-2 RNAs were detected by real-time fluorescence RT-PCR method. Serum SARS-CoV-2 IgG/IgM antibodies were determined by colloidal gold immunochromatography. The statistical analysis was performed using chi-squared test. RESULTS: In all the patients, SARS-CoV-2 RNA among 270 upper respiratory tract (nasal or throat swabs) samples, 71 lower respiratory tract (sputum) samples, and anti-SARS-CoV-2 IgM/IgG antibodies in 123 serum samples were detected during the hospitalization period. The positive rate of anti-SARS-CoV-2 IgG was significantly higher than that of anti-SARS-CoV-2 IgM within the first week after symptom onset (p < 0.05). The positive rate of anti-SARS-CoV-2 IgG was also significantly higher than that of anti-SARS-CoV-2 IgM during day 8 - 30 after symptom onset (p < 0.01). The positive rate of SARS-CoV-2 RNA in the lower respiratory tract specimens (64.8%, 46/71) was significantly higher than that in the upper respiratory tract (46.7%, 126/270) (p < 0.05). The positive rate (100%, 4/4) of SARS-CoV-2 RNA detection in the lower respiratory tract specimens before IgG seroconversion was significantly higher than that of the positive rate (59.3%, 32/54) after IgG seroconversion (p < 0.01). The positive rate (72.2%, 57/79) of SARS-CoV-2 RNA detection in the upper respiratory tract specimens before IgG seroconversion was significantly higher than that of the positive rate (30.7%, 39/127) after IgG seroconversion (p < 0.01). CONCLUSIONS: Anti-SARS-CoV-2 IgG might be detected within the first week after symptom onset. The application of SARS-CoV-2 antibody (IgG/IgM) detection is important for the suspected cases of SARS-CoV-2 infection with negative SARS-CoV-2 RNA results. The positive rate of SARS-CoV-2 RNA detection in the lower respiratory tract specimens was significantly higher than that in the upper respiratory tract. Sputum detection is recommended for the detection of SARS-CoV-2 RNA. Using lower respiratory tract specimens may reduce the false negative PCR tests. The detection of SARS-CoV-2 RNA can be improved by investigating follow-up specimens over time.

Moderate vs. mild cases of overseas-imported COVID-19 in Beijing: a retrospective cohort study.

This study compared the differences in the clinical manifestations, treatment courses and clinical turnover between mild and moderate coronavirus disease 2019 (COVID-19). Clinical data of the patients with imported COVID-19 admitted to Beijing Xiaotangshan Designated Hospital between March 15 and April 30, 2020, were retrospectively analysed. A total of 53 COVID-19 patients were included, with 21 mild and 32 moderate cases. Compared with the mild group, the moderate group showed significant differences in breathing frequency, lymphocyte count, neutrophil percentage, neutrophil/lymphocyte ratio, procalcitonin, C-reactive protein, and dynamic erythrocyte sedimentation rate. In the moderate group, 87.5% exhibited ground-glass opacities, 14% exhibited consolidative opacities, 53.1% exhibited local lesions and 68.8% exhibited unilateral lesions. The proportion of patients who received antiviral or antibiotic treatment in the moderate group was higher than that in the mild group, and the number of cases that progressed to severe disease in the moderate group was also significantly higher (18.7% vs. 0%, p = 0.035). Compared with patients with mild COVID-19, those with moderate COVID-19 exhibited more noticeable inflammatory reactions, more severe pulmonary imaging manifestations and earlier expression of protective antibodies. The overall turnover of the moderate cases was poorer than that of the mild cases.

Psychological Impact of COVID-19 Cases on Medical Staff of Beijing Xiaotangshan Hospital.

PURPOSE: To investigate the psychological impact of cases of coronavirus disease 19 (COVID-19) on medical staff of Beijing Xiaotangshan Hospital. METHODS: The 287 online questionnaires were distributed to medical staff working at Beijing Xiaotangshan Hospital, comprising three main sections and 17 questions: basic information, current departmental position, and the 12-item General Health Questionnaire (GHQ-12). The threshold for emotional distress was defined to be a total score of 4 on the GHQ-12 and above. RESULTS: A total of 255 members of medical staff participating in this study presented an emotional distress rate of 17%. Members who were male, aged 50-59, married with children, positioned as doctors, and in administration were the population with the highest rate of emotional distress. Furthermore, the severity of emotional distress among those under 30 was significantly lower than those aged 30-39 and 50-59. Doctors and other occupations shared a lower level of satisfaction on routine activities compared with nurses, so did staff in the administration compared with those who were working in screening or logistic departments. Besides, males and staff of the confirmation department had more difficulty in concentrating than females and those of the screening department, respectively. CONCLUSION: Medical staff working at Xiaotangshan Hospital underwent relatively low levels of emotional distress thanks to sufficient medical and psychological preparations. However, special attention should be paid to those who were male, married with children, senior, doctors, in administration, and in the confirmation department.

Diagnosis and microsurgical treatment of spinal hemangioblastoma.

Spinal cord hemangioblastomas are rare benign tumors, with difficult surgical management and poor prognosis due to high vascularization. We aim to evaluate the diagnostic methods and microsurgical treatment of spinal cord hemangioblastoma. This retrospective study assessed 25 patients treated for spinal hemangioblastoma using microsurgery at Beijing Tiantan Hospital and Department of Neurosurgery, The General Hospital of Chinese People's Armed Police Forces, between October 2008 and October 2013. Clinical, imaging, and treatment data were collected. Meanwhile, efficacy was assessed with the McCormick grading system for spinal cord function. The symptoms lasted 17.0 ± 15.1 months. Sixteen (64 %) patients were suffering from von Hippel-Lindau disease; magnetic resonance imaging revealed the lesions in all patients. Intraoperative fluorescence angiography was helpful in identifying the feeding arteries and draining veins. Total tumor removal was achieved in all subjects. Patients were followed up for 21.3 ± 8.5 months. One week after surgery, neurological symptoms were improved in 22 patients, remained stable in 2 patients, and were aggravated in 1. The latter patient began to recover 7-10 days after surgery and was completely recovered within a month. At the last follow-up, all patients were alive, and all showed a McCormick grade ≤II. Microsurgery seems effective in the treatment of spinal cord hemangioblastoma. Intraoperative fluorescence angiography is helpful in defining the resection scope, to reduce intraoperative bleeding and prevent spinal swelling, which results in improved success rate.

Comprehensive kinetic studies of acidic oil continuous esterification by cation-exchange resin in fixed bed reactors.

Biodiesel produced by esterification from molar ratio of methanol to free fatty acid (FFA) as 25:1 in presence of triglyceride was carried out with cation-exchange resin as a heterogeneous catalyst in three different scales of fixed bed reactors from minireactor (6.8 mm × 110 mm) to pilot scale reactor (70 mm × 1260 mm) at 338 K. The kinetic study of esterification was undertaken in terms of pseudo-homogeneous mechanism and performed as a first order reaction with elimination of the solid-liquid internal and external mass transfer resistances. Moreover, a kinetic model of FFA esterification was developed to illustrate the relationship between the FFA conversion and the catalyst bed height of fixed bed reactor. The model was also suitable for various resins in fixed bed reactor. The theoretical predictions were in agreement with the experimental data with root mean square (RMS) errors <10.

Continuous biodiesel production in a fixed bed reactor packed with anion-exchange resin as heterogeneous catalyst.

A continuous biodiesel production from the transesterification of soybean oil with methanol was investigated in a fixed bed reactor packed with D261 anion-exchange resin as a heterogeneous catalyst. The conversion to biodiesel achieved 95.2% within a residence time 56 min under the conditions: reaction temperature of 323.15K, n-hexane/soybean oil weight rate of 0.5, methanol/soybean oil molar ratio of 9:1 and feed flow rate of 1.2 ml/min. The resin can be regenerated in-situ and restored to the original activity to achieve continuous production after the resin deactivation. The product obtained was mainly composed of methyl esters. No glycerol in the product was detected due to the resin adsorbing glycerol in the fixed bed, which solved the issue of glycerol separation from biodiesel. It is believed that the fixed bed reactor with D261 has a potential commercial application in the transesterification of triglyceride.

[AIDS-related knowledge, attitudes and behaviors: a prevalence survey among 309 homosexual men in a Chinese city].

OBJECTIVE: To gain an insight into the demographic characteristics and AIDS-related knowledge, attitudes and behaviors of men who have sex with men (MSM) in a Chinese city, and to offer a base for preventive measures against AIDS. METHODS: We carried out a prevalence survey, using "snowball" methods to set up survey sites in the "comrade" community, the "comrades" looking for the respondents by various means. RESULTS: Among 309 respondents, 265 (85.8%) were younger than 30 years, 187 (60.5%) received college education or above, 187 (60.5%) were government officials or employees, and 91 (29.4%) were students; 299 (96.8%) were willing or very willing to get knowledge about HIV prevention and treatment, 201 (65.1%) considered themselves as MSM, 76 (24.6%) admitted bisexuality, 117 (37.9%) had insertion sex with at least three men in the past six months, 61 (19.7%) had two or more regular male sexual partners, 140 (45.3%) used condoms on >80% occasions and 34 (11.0%) occasionally or never used them during vaginal sex in the past six months. CONCLUSION: MSM in the city showed the characteristics of younger age, higher education, stable employment and income, more than one sexual partner, high frequency of high-risk behavior, and negligence of condom-use, and most (96.8%) of them are willing or very willing to obtain AIDS prevention knowledge, which deserves particular attention from relevant institutions.

A continuous process for biodiesel production in a fixed bed reactor packed with cation-exchange resin as heterogeneous catalyst.

Continuous esterification of free fatty acids (FFA) from acidified oil with methanol was carried out with NKC-9 cation-exchange resin in a fixed bed reactor with an internal diameter of 25 mm and a height of 450 mm to produce biodiesel. The results showed that the FFA conversion increased with increases in methanol/oil mass ratio, reaction temperature and catalyst bed height, whereas decreased with increases in initial water content in feedstock and feed flow rate. The FFA conversion kept over 98.0% during 500 h of continuous esterification processes under 2.8:1 methanol to oleic acid mass ratio, 44.0 cm catalyst bed height, 0.62 ml/min feed flow rate and 65°C reaction temperature, showing a much high conversion and operational stability. Furthermore, the loss of sulfonic acid groups from NKC-9 resin into the production was not found during continuous esterification. In sum, NKC-9 resin shows the potential commercial applications to esterification of FFA.

Biodiesel production using cation-exchange resin as heterogeneous catalyst.

Three types of cation-exchange resins (NKC-9, 001 x 7 and D61) as solid acid catalysts were employed to prepare biodiesel from acidified oils generated from waste frying oils. The results show that the catalytic activity of NKC-9 was higher than that of 001 x 7 and D61. The conversion of the esterification by NKC-9 increased with increasing in the amount of catalyst, reaction temperature and time and methanol/oil molar ratio. The maximal conversion of reaction is approximately 90.0%. Furthermore, NKC-9 resin exhibits good reusability. Gas chromatography-mass spectrometry analysis reveals that the production is simplex and mainly composed of C16:0 (palmitic), C18:2 (linoleic), and C18:1 (oleic) acids of methyl ester, respectively.