Biomedical subjects

Kun Lin

Publications and source records attributed to Kun Lin.

10 recordsLinked to original sources

PubMed2026

Minimal Transport Units Govern Oxygen-Defect Stabilization and Transport for Lightweight Solid Electrolytes.

Solid electrolytes are central to electrochemical energy technologies, including fuel cells, sensors, catalysis, membrane separation, and electrolyser. However, most established oxide-ion solid electrolytes are built around heavy B-site cations embedded in rigid and highly connected coordination frameworks, leading to widespread high-weight and sluggish ionic transport that is strongly coupled to large-amplitude lattice relaxations. This intrinsic challenge hinders further performance optimization and constrains the rational design of lightweight electrolytes. Herein, we propose a minimal transport unit-based design paradigm that combines simplified structural motifs with light-element chemistry, enabled by the exceptional flexibility of B-O polyhedra in coordination, rotation, deformation, and connectivity. As a proof of concept, Sc1- xZnxBO3- x /2, constructed from isolated BO3 units, exhibits high oxide ion conductivity (σ(1000°C) ∼ 1.5 × 10-2 S/cm), alongside excellent thermo-mechanical stability. Oxygen vacancies are stabilized through the formation of B2O5 units rather than isolated BO2 species. Long-range oxide-ion migration is mediated by dynamic oxygen exchange between minimal BO3 and B2O5 units via continuous breaking and reforming of B2O5 units, with transient BO2 configurations as intermediates. This study demonstrates minimal transport units as a governing principle for defect stabilization and ionic conduction in lightweight solid electrolytes, offering a general design framework for portable and scalable high-temperature energy technologies.

NMR spectroscopy and variable‐temperature P↗

PubMed2006

Environmental factors on the SARS epidemic: air temperature, passage of time and multiplicative effect of hospital infection.

The study sought to identify factors involved in the emergence, prevention and elimination of severe acute respiratory syndrome (SARS) in Hong Kong during 11 March to 22 May 2003. A structured multiphase regression analysis was used to estimate the potential effects of weather, time and interaction effect of hospital infection. In days with a lower air temperature during the epidemic, the risk of increased daily incidence of SARS was 18.18-fold (95% confidence interval 5.6-58.8) higher than in days with a higher temperature. The total daily new cases might naturally decrease by an average of 2.8 patients for every 10 days during the epidemic. The multiplicative effect of infected hospital staff with patients in an intensive care unit (ICU) and the proportion of SARS patients in ICUs might respectively increase the risk of a larger SARS epidemic in the community. The provision of protective gear in hospitals was also a very important factor for the prevention of SARS infection. SARS transmission appeared to be dependent on seasonal temperature changes and the multiplicative effect of hospital infection. SARS also appeared to retreat naturally over time.

Cross Infection↗

PubMed2005

Risk factors associated with rheumatic complaints: a WHO-ILAR COPCORD study in Shantou, Southeast China.

OBJECTIVE: To validate the differences of the prevalence of rheumatic symptoms between the north and south part of China and to investigate the associated risk factors for rheumatic complaints in Shantou, China. METHODS: Four samples together comprising 10,638 people > or = 16 years of age were surveyed in 1987, 1992, 1995, and 1999. The protocol of the ILAR-China Collaborative Study or the WHO-ILAR COPCORD Core Questionnaire was implemented. Data on rheumatic symptoms that were part of these surveys were collected and analyzed. RESULTS: The prevalence rate of rheumatic complaints was increasing in the Shantou area during the recent decade (in 1987 11.6%, 1992 12.5%, 1995 16.0%, and 1999 19.8%). However, it was still lower than the rate in Beijing, China, in 1987 (40.0%). Rheumatic symptoms were more prevalent in women than in men, and were more frequently seen in the elderly than in young people. The most frequently involved site was the low back followed by the knee and neck. Lumbar pain was more frequent among rural residents, while neck pain was more prevalent in the urban school-age population group. The prevalence of knee pain was significantly higher in people living in multi-story buildings without elevators compared with those living in single-story houses. The peak value of bone mineral density (BMD) in the Shantou population was 0.839 +/- 0.085 g/cm2 in men, and 0.723 +/- 0.064 g/cm2 in women, significantly higher than that reported in 13 other provinces and cities of China including Beijing. The sense of seeking a physician's care was higher in the population with a higher prevalence of rheumatic symptoms than that in the group with a lower prevalence of complaints. However, no significant difference was found in the rate of disability among the different population samples. CONCLUSION: The prevalence rate of rheumatic complaints was lower in Shantou than in Beijing. Socioeconomic status, environmental differences (e.g., Shantou in the southern and Beijing in the northern part of China), sex, age, occupation, ergonomics, BMD, and awareness of seeking medical care might all be risk factors associated with the prevalence of rheumatic complaints.

Adolescent↗

PubMed2005

[Study on N-nitroso compound in food and its relevant risk factors for esophageal cancer].

OBJECTIVE: To study multiple risk factors of N-nitroso compounds (NOC) in high- and low-risk areas for esophageal cancer in southern China. METHOD: The samples of 24-hr diets and 12-hr overnight urine were collected from 120 male healthy subjects (35-64 years old) selected by a 3-stage random cluster sample procedure in each of the high-risk area (Nanao County) and low-risk area (Lufeng County) for esophageal cancer. The urinary samples were respectively collected from undosed subjects, subjects ingested 500 mg L-proline (together with 200 mg ascorbic acid ) and subjects ingested 500 mg proline. The levels of total NOC (TNOC), N-nitrosamino acids (NAAs), volatile N-nitroso compounds and reductive ascorbic acid (VC) in the samples were measured. By unconditional logistic stepwise regression model, we analyzed the association between the multiple factors of NOC and esophageal cancer mortality. The factors included the intake and excretion levels of various kinds of NOC, the ability of NAAs endogenous formation and its inhibition by VC, and nutrition status of VC in the body. RESULTS: The results of unconditional logistic stepwise regression showed that risk factors entered the model were diet TNOC content (OR 9.613, 95% CI 1.921-48.115) and urinary NAAs level after ingested VC (OR 1.137, 95 % CI 1.001-1.298). CONCLUSION: The higher level of diet TNOC and the lower inhibition ability of NOC endogenous formation by VC were important risk factors on NOC etiology of esophageal cancer in southern China.

Adult↗

PubMed2005

[Study on the associated risk factors of rheumatic pain: a ILAR-China, WHO COPCORD Shantou study].

OBJECTIVE: To validate the difference on the prevalence of rheumatic symptoms between north and south parts of the country and to study the associated risk factors of rheumatic complaints in Shantou city, China. METHODS: A total number of 10 638 people at above 16 years of age from four samples, were surveyed in 1987, 1992, 1995, and 1999. Protocol of International League Against Rheumatism (ILAR)-China collaborative study or WHO-ILAR community oriented program for control of rheumatic disease(COPCORD) core questionnaire was implemented. Data on related rheumatic symptoms were collected and analyzed. RESULTS: The prevalence rate of rheumatic complaints had been increasing in Shantou area during the last decade (in 1987 11.6%, 1992 12.5%, 1995 16.0% and 1999 19.8%) but still lower than that seen in Beijing, China in 1987(40.0%). Rheumatic symptoms were more prevalent in females than in males, in elderly than in young people with most frequently involved site happened in low back area, followed by knee and neck. Lumbar pain was more frequent among rural residents, while neck pain was more prevalent in urban school students. Prevalence of knee pain was significantly higher in people living in multi-storey buildings without elevator than those living in single-storey houses. The peak values of Bone Mineral Density in Shantou population were (0.839 +/- 0.085) g/cm2 in men, and (0.723 +/- 0.064) g/cm2 in women, significantly higher than that reported in 13 other provinces and cities including Beijing. The sense of seeking for medical help was higher in population with higher prevalence of rheumatic symptoms than that in lower complaints group. However, no significant difference was found in the rates of disability among the different populations. CONCLUSION: The prevalence rate of rheumatic complaints was lower in Shantou than that in Beijing. Socio-economic status, environment, sex, age, occupation, ergonomics, bone mineral density, and awareness of seeking medical care might have been the associated risk factors to the prevalence of rheumatic complaints.

Adult↗

PubMed2003

Estimation of the potential for nitrosation and its inhibition in subjects from high- and low-risk areas for esophageal cancer in southern China.

We studied 2 counties in southern China, which are close to each other but show very different mortality rates from esophageal cancer. We collected 12 hr urine samples and analyzed them for NPRO, other nitrosamino acids, nitrate and ASC. The potential for forming NPRO and the effect on inhibition by ASC were recorded. Urine was collected after (i) no treatment, (ii) a dose of proline and (iii) proline with ASC. Intake and excretion of nitrate were significantly greater in the high-risk area. After the proline dose, urinary excretion of NPRO was significantly greater in the high-risk area. The inhibitory effect of ASC after taking it with proline was less in the high-risk area. Hence, the high-risk area showed greater potential for forming NPRO, and this formation was less inhibited by ASC. This supports the view that esophageal cancer in this area may be caused by nitrosamines formed in vivo, perhaps from nitrite produced by reduction of ingested nitrate.

China↗

PubMed2002

Dietary exposure and urinary excretion of total N-nitroso compounds, nitrosamino acids and volatile nitrosamine in inhabitants of high- and low-risk areas for esophageal cancer in southern China.

We assessed the exposure of total N-nitroso compounds (TNOCs) in the inhabitants of high- and low-risk areas for esophageal cancer in southern China. Samples of 24 hr diet and 12 hr overnight urine were collected from 120 male adults in each of the 2 areas, a high-risk area (Nan'ao County) and a low-risk area (Lufeng County) for esophageal cancer. Annual standardized mortality rates of esophageal cancer in Nan'ao and Lufeng are 110/10(6) and 10/10(6) respectively. The 240 healthy male subjects (35-64 years old) were selected by a 3-stage random cluster sample procedure. Levels of TNOCs, NAAs and volatile nitrosamines in the samples were measured. The TNOC detection rate (95%) in the diet, the TNOC daily intake (4.25 +/- 0.84 micromol), TNOC excretion levels (0.04 +/- 0.01 nmol/12 hr) and daily intake of volatile nitrosamines (5.84 +/- 0.71 micromol) in the high-risk area were significantly greater than values in the low-risk area (A +/- B = mean +/- SE). The TNOC detection rate in the diet, the TNOC daily intake, TNOC excretion levels and daily intake of volatile nitrosamines in the low-risk area were 70%, 0.25 +/- 0.06 micromol, 0.02 +/- 0.01 nmol/12 hr and 3.18 +/- 0.31 micromol, respectively. NAA excretion levels showed no difference between the 2 areas (16.3 +/- 7.18 micromol/12 hr for Nan'ao and 31.2 +/- 26.4 micromol/12 hr for Lufeng). Thus, TNOCs are implicated in the etiology of esophageal cancer in southern China.

Adult↗

PubMed2002

[Association between the excretion levels of urinary TNOC and NAAs in the inhabitants of high and low risk area for esophageal cancer in southern China].

To assess the role of urinary total N-nitroso compounds(TNOC) index in study etiology of N-nitroso compounds(NOC) of esophageal cancer in southern China and to study the association between TNOC index and traditional indexes of N-nitrosamino acids(NAAs). The samples of 12-hr overnight urine were collected from 120 male adults in high-risk area (Nanao county) and low-risk area(Lufeng county) for esophageal cancer. The 240 male healthy subjects(35-64 years old) were selected by a 3-stage random cluster sample procedure. Levels of TNOC and 4 categories of NAAs were measured in samples. The results showed that Urinary TNOC contents were positively correlated with esophageal cancer mortality in the south(rs = 0.25, P < 0.05). Only 7.5% content of urinary TNOC came from the 4 categories of NAAs in the high-risk area when 57% content of urinary TNOC came from the NAAs in the low-risk area. The urinary NOC components in the high-risk area were more complex than the components in the low-risk area. Urinary TNOC is a better index that is applied to assess the exposure dose of TNOC in humans and study etiology of NOC of esophageal cancer. When the categories of NOC in urine are less, TNOC index is correlated with NAAs indexes. The results imply that TNOC are implicated in the etiology of esophageal cancer in southern China.

Adult↗

PubMed2002

[Exposure level of total N-nitroso compounds in residents of high-and low-risk areas for esophageal cancer in southern].

OBJECTIVE: To assess the exposure level of total N-nitroso compounds (TNOCs) in the residents of high- and low-risk areas for esophageal cancer in southern China. METHODS: Samples of duplicate plate diets and 12 hr overnight urine were collected from 120 male adults in each of the 2 areas, a high-risk area (Nanao county) and a low-risk area (Lufeng county) for esophageal cancer. The 240 male healthy subjects (35 - 64 years old) were selected by a 3-stage random cluster sampling procedure. Levels of TNOC, N-nitrosamino acids (NAAs) and volatile N-nitroso compounds (VNOC) in the samples were measured by Thermo Energy Analyzer. RESULTS: The detectable rate (95%) of diet TNOC, daily dietary TNOC intake (4.25 +/- 0.84) micromol/day, 12-hr urinary TNOC excretion levels (1.76 +/- 0.23 ng/12 h) and daily dietary intake of VNOC (266 +/- 31.2 microg/day) in the high-risk area were all significantly higher than those of the low-risk area. Oesophageal cancer mortality rates were positively and significantly associated with daily dietary TNOC intake and 12-hr urinary TNOC excretion. Urinary NAAs excretion levels were not different in the two areas. CONCLUSION: The results suggest that TNOCs may be implicated in the etiology of esophageal cancer in southern China.

Adult↗

PubMed2002

Intake of volatile N-nitrosamines and their ability to exogenously synthesize in the diet of inhabitants from high-risk area of esophageal cancer in southern China.

OBJECTIVE: Nan'ao County in Guandong Province is a high-risk area of esophageal cancer in Southern China. Of the suspected etiological factors in the environment, N-nitrosamines and their precursors have received the greatest attention. METHODS: Sixty samples of the diet ingested by the inhabitants were collected and detected for volatile N-nitrosamines and their precursors. Five N-nitrosamines detected by Gas Chromatography-Thermal Energy Analyzer were N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosopyrrolidine, N-nitrosopiperidine and N-nitrosomethyl-benzylamine. RESULTS: The average content of 5 volatile N-nitrosamines in the diet was 312.0 micrograms/kg (median). The daily intake of the nitrosamines was 286.5 micrograms/head/day. Only the ability to exogenously synthesize N-nitrosopiperidine was powerful among 5 volatile N-nitrosamines. By a computerized stepwise regression analysis and curve fitting, we studied the correlation among the nitrosamines, the precursors and the major food items in the samples. CONCLUSION: It demonstrated that a relatively high content of volatile N-nitrosamines was present in the diet collected in the area.

Adult↗