[Comparison of the efficacy of different surgical strategies in the treatment of patients with initially resectable gastric cancer liver metastases]

Objective: To examine the impact of varied surgical treatment strategies on the prognosis of patients with initial resectable gastric cancer liver metastases (IR-GCLM). Methods: This is a retrospective cohort study. Employing a retrospective cohort design, the study selected clinicopathological data from the national multi-center retrospective cohort study database, focusing on 282 patients with IR-GCLM who underwent surgical intervention between January 2010 and December 2019. There were 231 males and 51 males, aging (M(IQR)) 61 (14) years (range: 27 to 80 years). These patients were stratified into radical and palliative treatment groups based on treatment decisions. Survival curves were generated using the Kaplan-Meier method and distinctions in survival rates were assessed using the Log-rank test. The Cox risk regression model evaluated HR for various factors, controlling for confounders through multivariate analysis to comprehensively evaluate the influence of surgery on the prognosis of IR-GCLM patients. A restricted cubic spline Cox proportional hazard model assessed and delineated intricate associations between measured variables and prognosis. At the same time, the X-tile served as an auxiliary tool to identify critical thresholds in the survival analysis for IR-GCLM patients. Subgroup analysis was then conducted to identify potential beneficiary populations in different surgical treatments. Results: (1) The radical group comprised 118 patients, all undergoing R0 resection or local physical therapy of primary and metastatic lesions. The palliative group comprised 164 patients, with 52 cases undergoing palliative resections for gastric primary tumors and liver metastases, 56 cases undergoing radical resections for gastric primary tumors only, 45 cases undergoing palliative resections for gastric primary tumors, and 11 cases receiving palliative treatments for liver metastases. A statistically significant distinction was observed between the groups regarding the site and the number of liver metastases (both P<0.05). (2) The median overall survival (OS) of the 282 patients was 22.7 months (95%CI: 17.8 to 27.6 months), with 1-year and 3-year OS rates were 65.4% and 35.6%, respectively. The 1-year OS rates for patients in the radical surgical group and palliative surgical group were 68.3% and 63.1%, while the corresponding 3-year OS rates were 42.2% and 29.9%, respectively. A comparison of OS between the two groups showed no statistically significant difference (P=0.254). Further analysis indicated that patients undergoing palliative gastric cancer resection alone had a significantly worse prognosis compared to other surgical options (HR=1.98, 95%CI: 1.21 to 3.24, P=0.006). (3) The size of the primary gastric tumor significantly influenced the patients' prognosis (HR=2.01, 95%CI: 1.45 to 2.79, P<0.01), with HR showing a progressively increasing trend as tumor size increased. (4) Subgroup analysis indicates that radical treatment may be more effective compared to palliative treatment in the following specific cases: well/moderately differentiated tumors (HR=2.84, 95%CI 1.49 to 5.41, P=0.001), and patients with liver metastases located in the left lobe of the liver (HR=2.06, 95%CI 1.19 to 3.57, P=0.010). Conclusions: In patients with IR-GCLM, radical surgery did not produce a significant improvement in the overall prognosis compared to palliative surgery. However, within specific patient subgroups (well/moderately differentiated tumors, and patients with liver metastases located in the left lobe of the liver), radical treatment can significantly improve prognosis compared to palliative approaches.

[Association of urinary cadmium level with body mass index and body circumferences among older adults over 65 years old in 9 longevity areas of China]

Objective: To investigate the association of urinary cadmium level with body mass index (BMI) and body circumferences among the older adults over 65 years old in 9 longevity areas of China. Methods: Subjects were older adults over 65 years old from the Healthy Aging and Biomarkers Cohort Study (HABCS) between 2017 and 2018 conducted in 9 longevity areas in China. A total of 1 968 older adults were included in this study. Information including socio-demographic characteristics, lifestyles, diet intake, and health status was collected by using questionnaires and physical examinations. Urine samples were collected to detect urinary cadmium and creatinine levels. Body circumferences included waist circumference, hip circumference and calf circumference. Subjects were divided into three groups (low:<0.77 μg/g·creatinine, middle:0.77-1.69 μg/g·creatinine, high:≥1.69 μg/g·creatinine) by tertiles of creatinine-adjusted urinary cadmium concentration. Multiple linear regression models were used to analyze the association of creatinine-adjusted urinary cadmium level with BMI and body circumferences. The dose-response relationship of creatinine-adjusted urinary cadmium concentration with BMI and body circumferences was analyzed by using restrictive cubic splines fitting multiple linear regression model. Results: The mean age of subjects was (83.34±11.14) years old. The median (Q1, Q3) concentration of creatinine-adjusted urinary cadmium was 1.13 (0.63, 2.09) μg/g·creatinine, and the BMI was (22.70±3.82) kg/m2. The mean values of waist circumference, hip circumference, and calf circumference were (85.42±10.68) cm, (92.67±8.90) cm, and (31.08±4.76) cm, respectively. After controlling confounding factors, the results of the multiple linear regression model showed that for each increment of 1 μg/g·creatinine in creatinine-adjusted urinary cadmium, the change of BMI, waist circumference, hip circumference, and calf circumference in the high-level group was -0.28 (-0.37, -0.19) kg/m2, -0.74 (-0.96, -0.52) cm, -0.78 (-0.96, -0.61) cm, and -0.20 (-0.30, -0.11) cm, respectively. The restrictive cubic splines curve showed a negative nonlinear association of creatinine-adjusted urinary cadmium with BMI (Pnonlinear<0.001) and negative linear associations of creatinine-adjusted urinary cadmium with waist circumference (Plinear<0.001), hip circumference (Plinear<0.001), and calf circumference (Plinear<0.001). Conclusion: Urinary cadmium level is significantly associated with decreased BMI, waist circumference, hip circumference and calf circumference among older adults over 65 years old in 9 longevity areas of China.

Geodynamic models of Indian continental flat slab subduction with implications for the topography of the Himalaya-Tibet region

The slab structure and high elevation of the Himalaya-Tibet region and their underlying mechanisms have been widely discussed. Many studies interpret a flat slab segment of Indian continental lithosphere located below the overriding plate, but interpretations of the northward extent of the flat slab differ substantially, with minimum estimates placing the boundary at the northern margin of the Himalaya (Indus-Yarlung Tsangpo suture), and maximum estimates placing it at the northern boundary of Tibet. In this study, we investigate for the first time if a flat slab segment of subducted buoyant Indian continental lithosphere below the Himalaya-Tibet region is geodynamically feasible and we quantify its northward extent, as well as its contribution to the high topography of the region. We conduct three large-scale fully-dynamic (buoyancy-driven) analogue experiments to simulate the subduction of the Indian continent. Our preferred, and geodynamically most feasible, model shows a continental flat slab extending northward up to ~ 320 km from the Himalayan thrust front, in agreement with recent estimates. Furthermore, it suggests that the positively buoyant flat slab segment of the Indian continent contributes some ~ 1.5-2 km to the high topography of the Himalaya-Southern Tibet region by providing an upward force to elevate the overriding Eurasian plate.

[Effects of laparoscopic hyperthermic intraperitoneal perfusion chemotherapy combined with intraperitoneal and systemic chemotherapy treatment in patients with untreated gastric cancer with peritoneal metastasis]

Objective: To investigate the efficacy of laparoscopic hyperthermic intraperitoneal perfusion chemotherapy combined with intraperitoneal and systemic chemotherapy (HIPEC-IP-IV) in the treatment of peritoneal metastases from gastric cancer (GCPM). Methods: This was a descriptive case series study. Indications for HIPEC-IP-IV treatment include: (1) pathologically confirmed gastric or esophagogastric junction adenocarcinoma; (2) age 20-85 years; (3) peritoneal metastases as the sole form of Stage IV disease, confirmed by computed tomography, laparoscopic exploration, ascites or peritoneal lavage fluid cytology; and (4) Eastern Cooperative Oncology Group performance status 0-1. Contraindications include: (1) routine blood tests, liver and renal function, and electrocardiogram showing no contraindications to chemotherapy; (2) no serious cardiopulmonary dysfunction; and (3) no intestinal obstruction or peritoneal adhesions. According to the above criteria, data of patients with GCPM who had undergone laparoscopic exploration and HIPEC from June 2015 to March 2021 in the Peking University Cancer Hospital Gastrointestinal Center were analyzed, after excluding those who had received antitumor medical or surgical treatment. Two weeks after laparoscopic exploration and HIPEC, the patients received intraperitoneal and systemic chemotherapy. They were evaluated every two to four cycles. Surgery was considered if the treatment was effective, as shown by achieving stable disease or a partial or complete response and negative cytology. The primary outcomes were surgical conversion rate, R0 resection rate, and overall survival. Results: Sixty-nine previously untreated patients with GCPM had undergone HIPEC-IP-IV, including 43 men and 26 women; with a median age of 59 (24-83) years. The median PCI was 10 (1-39). Thirteen patients (18.8%) underwent surgery after HIPEC-IP-IV, R0 being achieved in nine of them (13.0%). The median overall survival (OS) was 16.1 months. The median OS of patients with massive or moderate ascites and little or no ascites were 6.6 and 17.9 months, respectively (P<0.001). The median OS of patients who had undergone R0 surgery, non-R0 surgery, and no surgery were 32.8, 8.0, and 14.9 months, respectively (P=0.007). Conclusions: HIPEC-IP-IV is a feasible treatment protocol for GCPM. Patients with massive or moderate ascites have a poor prognosis. Candidates for surgery should be selected carefully from those in whom treatment has been effective and R0 should be aimed for.

[Endoscopic transoral approach nasopharyngectomy for petroclival and jugular foramen nasopharyngeal carcinoma]

Objective: To describe a technique of endoscopic transoral approach nasopharyngectomy for petroclival and jugular foramen nasopharyngeal carcinoma, based on anatomic studies and surgeries. Methods: Three dry human skulls and five fresh human cadaver heads were used for anatomic study of a endoscopic transoral approach to expose petroclival and jugular foramen. The anatomical landmarks and the extent of exposure were recorded. Six clinical cases who were treated in Eye & ENT Hospital, Fudan University from June 2020 to April 2022 were used to illustrate the technique and feasibility of this approach and to assess its indications and advantages, including 3 males and 3 females, aged 42 to 69 years old. Descriptive analysis was used in this research. Results: On the basis of the preservation of the internal pterygoid muscle and the external pterygoid muscle, this approach could fully expose the parapharyngeal, petrosal and paraclival segment internal carotid arteries, and safely deal with the lesions of jugular foramen and petroclival region. The 6 patients in our study tolerated the procedure well. Postoperative enhanced MRI showed complete resection of the tumor and no postoperative masticatory dysfunction. Conclusion: Endoscopic transoral approach is a safe, minimally invasive and effective surgical treatment for petroclival and jugular foramen recurrent nasopharyngeal carcinoma.

[Analysis of clinical prognosis of endoscopic salvage surgery in patients with rT2 recurrent nasopharyngeal carcinoma]

Objective: To investigate the feasibility of endoscopic salvage surgery for patients with rT2 recurrent nasopharyngeal carcinoma (rNPC) and to analyze their prognostic factors. Methods: The clinical data of 33 patients with rT2 rNPC who underwent endoscopic extended nasopharyngectomy in Eye & ENT Hospital Affiliated to Fudan University from January 2015 to July 2020 were analyzed, including 29 males (87.9%) and 4 females (12.1%), aging (51.7±10.6) years. The clinicopathological characteristics of these patients were recorded and analyzed, in terms of gender, sex, alcohol and cigarette use, interval between primary treatment to recurrence, adjuvant therapy, lymph node metastasis, internal carotid artery (ICA) invasion, necrosis, margin and reconstruction materials. Kaplan Meier analysis was used to plot the overall survival rate and progression free survival rate curve, Log-rank test was used to analyze the prognostic factors among patients, and multivariate Cox proportional hazards regression was used to determine the independent risk factors of tumor progression free survival. Results: Among 33 patients with rT2 rNPC, the recurrence interval of 24 patients with rNPC after primary radiotherapy was more than 2 years. A total of 25 patients received primary radiotherapy and adjuvant chemotherapy at the same time. There were 6 cases with cervical lymph node metastasis, 12 cases with ICA invasion, 8 cases with positive surgical margin, 7 cases underwent ICA embolization before operation. A total of 18 cases underwent pedicled tissue flap repairment after operation, including 12 pedicled nasal septal mucosa flaps and 6 temporalis muscle flaps. The median follow-up time was 15 months. Five patients died because of disease progression (in 2 cases), post surgical ICA hemorrhage (in 1 case), liver metastasis (in 1 case) and dysphagia (in 1 case). The 1-year, 2-year and 3-year overall survival rates of all patients were 93.9%, 81.8% and 81.8%, respectively. The 1-year, 2-year and 3-year progression free survival rates were 74.7%, 59.7% and 40.9%, respectively. Log-rank statistical analysis showed that the positive surgical margin (P=0.060) and recurrence interval (P=0.151) were possibly related to the prognosis of rT2 rNPC. Multivariate Cox regression analysis showed that the positive surgical margin was an independent risk factor for patients with rT2 rNPC (P=0.034). Nasopharynx hemorrhage occurred in 4 patients, skull base bone necrosis occurred in 2 patients, trismus occurred in 3 patients, and no obvious brain complications occurred in 7 patients with ICA embolization. Conclusion: Endoscopic salvage surgery for rT2 rNPC is a safe and effective surgical option, but the long-term effect still needs long-term follow-up in bulk cases.

[The application of temporalis muscle flap in the salvage nasopharyngectomy for advanced recurrent nasopharyngeal carcinoma]

Objective: To summarize the application of temporalis muscle flap in the salvage nasopharyngectomy for advanced recurrent nasopharyngeal carcinoma (rNPC), and to provide guidance for the repair of extensive skull base defects in salvage rNPC. Methods: A total of 54 patients with the application of temporalis muscle flap in the salvage nasopharyngectomy for advanced rNPC were retrospectively analyzed, including 42 males and 12 females, aging from 29 to 71 years. There were 36 patients with rT3 and 18 patients with rT4. The surgical methods of temporalis muscle flap repair were summarized. The general situation, survival time and postoperative complications of patients were recorded, and the advantages and disadvantages of temporalis muscle flap were discussed. Results: The temporal muscle flap could completely cover the defect area of nasopharynx and skull base, without the need for other autologous repair materials. The follow-up period was 2 to 28 months. The survival rate of temporalis flap was 98.1% (53/54). The 1-year overall survival rate was 84.5% while 1-year progression-free survival rate was 49.0%. None of the patients had facial nerve injury. Three patients (5.6%) had necrosis of the cranial membrane required surgical intervention and four patients (7.4%) required a chonoplasty due to severe chonostril stenosis or chonostril atresia. Eleven cases (20.4%) had mouth opening restriction, chewing weakness, dysphagia and other eating difficulties. Conclusions: Temporalis muscle flap is an alternative flap for the salvage nasopharyngectomy for advanced rNPC. Temporal muscle flap shows high survival rate and wide coverage, but the surgeon should apprehend the possible complications and reduce the occurrence of them.

[Association of body mass index and waist circumference with frailty among people aged 80 years and older in Chinese]

Objective: To examine the association of body mass index (BMI) and waist circumference (WC) with frailty among oldest-old adults in China. Methods: A total of 7 987 people aged 80 years and older (oldest-old) who participated in the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2017-2018 were included. Information on demographic characteristics, behavior pattern, diet, activities of daily living, cognitive function, health status, disease condition were collected by questionnaire and physical examination. Generalized linear mixed model and restricted cubic splines (RCS) were used to analyze the association of BMI and WC with frailty. Results: The mean age of all participants was 91.7 years, and their mean BMI and WC were (21.3±3.5) kg/m² and (82.9±10.5) cm, respectively. The proportion of male was 42.3% (3 377/7 987), and the proportion of people with frailty was 33.7% (2 664/7 987). After controlling confounding factors, compared with T₂ (19.1-22.1 kg/m²) of BMI, the OR (95%CI) of the female T₁ (<19.1 kg/m²) and T₃ (≥22.2 kg/m²) group was 1.39 (1.17-1.65) and 1.27 (1.07-1.52), respectively. Compared with T₂ (77-85 cm) of WC, the OR (95%CI) of female T₁ (<77 cm) and T₃ (≥86 cm) group was 1.20 (1.01-1.42) and 1.10 (0.93-1.31), respectively. The results of multiple linear regression model with restrictive cubic spline showed that there was a non-linear association of BMI and WC with frailty in female. Conclusion: There is a U-shaped association of BMI and WC with frailty in female participants.

[Interpretation of the expert consensus on the whole-process management of herpes zoster-associated pain]

Currently, the diagnosis, treatment and management of herpes zoster-associated pain are not well understood in China. The expert consensus on the whole-process management of herpes zoster-associated pain was focused on the standardization of diagnosis and treatment of herpes zoster-associated pain, such as the time definition of clinical stages, the relevant details of analgesic drugs and minimally invasive interventional therapy, and the value of vaccines in pain management. This article gives a detailed interpretation of the associated content in the consensus.

[The impact of different comprehensive treatment models on patients with adenocarcinoma of esophagogastric junction based on propensity score matching: a single center cohort study]

Objective: To compare the prognostic influence and postoperative pathology of different comprehensive treatment models for adenocarcinoma of esophagogastric junction. Methods: Between January 2012 and December 2017, a total of 219 patients with adenocarcinoma of esophagogastric junction underwent surgery in Gastrointestinal Cancer Center, Peking University Cancer Hospital & Institute and were enrolled in this study. The clinicopathological data of these patients were collected. The patients were categorized into 3 groups according to different treatment models: surgery-first group, neoadjuvant chemotherapy (NAC) group and neoadjuvant chemoradiotherapy (nCRT) group. A trimatch propensity score analysis was applied to control potential confounders among the three groups by using R language software. A total of 7 covariates including gender, age, comorbidity, body mass index, clinical T stage, clinical N stage and Siewert type were included, and the caliper value was taken as 0.2. After matching, a total of 87 patients were included for analysis with 27 patients for each group. There were 82 males and 5 females, with a median age of 63 years (range: 38 to 76 years). The effect of preoperative treatment on postoperative tumor pathology among the three different comprehensive treatment models was explored by χ² test, ANOVA or Wilcoxon rank sum test. Mann-Whitney U test or χ² test were used to undergo pairwise comparisons. Kaplan-Meier method and Log-rank test were used to analyze the overall survival and progression-free survival. Results: The proportion of vascular embolism in the surgery-first group was 72.4% (21/29), which was significantly higher than NAC group (37.9% (11/29), χ²=6.971, P=0.008) and nCRT group (6.9% (2/29), χ²=26.696, P<0.01). The proportions of pathological T3-4 stage in nCRT group and NAC group were 55.2% (16/29) and 62.1% (18/29), respectively, which were significantly lower than the surgery-first group (93.1% (27/29), χ²=10.881, P=0.001; χ²=8.031, P=0.005). Compared with the NAC group (55.2% (16/29), χ²=6.740, P=0.009) and nCRT group (31.0% (9/29), χ²=18.196, P<0.01), the proportion of lymph node positivity 86.2% (25/29) were significantly higher in the surgery-first group. The 5-year overall survival rates were 62.1%, 68.6% and 41.4% for the surgery-first group, NAC group and nCRT group, respectively (χ²=4.976, P=0.083). The 5-year progression-free survival rates were 61.7%, 65.1% and 41.1% for the surgery-first group, NAC group and nCRT group, respectively. The differences in overall survival (χ²=4.976, P=0.083) and progression-free survival (χ²=4.332, P=0.115) among the three groups were nonsignificant. Conclusions: Postoperative pathology is significantly different among the three groups. Neoadjuvant chemotherapy and neoadjuvant chemoradiotherapy could decrease the proportions of vascular embolism, pathological T3-4 stage and lymph node positivity to achieve local tumor control. The prognosis of overall survival and progression-free survival are not significantly different among the three groups.

[Analysis and management of delayed cerebrospinal fluid rhinorrhea after invasive pituitary adenoma surgery]

Objective: To investigate the related factors and treatments of delayed cerebrospinal fluid rhinorrhea (CFR) after invasive pituitary adenoma (IPA) surgery. Methods: One hundred and forty-two patients with IPA treated in Tianjin Huanhu Hospital from January 2014 to January 2019 were analyzed retrospectively, including 62 males and 80 females, aging from 38 to 67 years. The clinical data of patients before and after operation were collected. All patients with postoperative CFR underwent endoscopic CFR repair. During the operation, residual or recurrent pituitary adenomas were resected, the dura around the leak was enlarged and the necrotic tissue was removed. For those who still had fluid leakage after repair, the necrotic tissue was cleaned up, the leakage was filled and reinforced under endoscopy. Endoscopic rhinorrhea repair was performed if necessary. The cerebrospinal fluid leak was repaired with multi-layer materials. The related risk factors of delayed CFR after operation were analyzed. SPSS 19.0 software was used for statistical analysis. Results: Among the 142 patients in this group, 64 cases underwent total tumor resection and 78 cases underwent non-total tumor resection. They were followed up for 6 to 72 months. Thirty-one cases had delayed CFR, with an incidence of 21.83%, and occurred between 1 and 5 years postoperatively, with an average of 2.4 years. All 31 patients with delayed CFR underwent endoscopic CFR repair. The nasal endoscopy was rechecked at 2 weeks, 1 month, 3 months and 6 months after operation. Twenty-eight patients were repaired successfully after 1 operation, while 2 patients after 2 operations and 1 patient after 3 operations. These patients were followed up for 6 to 60 months, and no CFR occurred again. Univariate analysis showed that the degree of tumor resection, recurrence, size, texture, postoperative radiotherapy and operator experience were the risk factors of delayed CFR (all P<0.05). Multivariate analysis showed that the degree of tumor resection and recurrence were the highest independent risk factors for postoperative CFR, and tumor size, texture, postoperative radiotherapy and operator experience were the independent risk factors in this study. Conclusions: Delayed CFR after IPA is related to the degree of tumor resection, recurrence, size, texture, postoperative radiotherapy and the operator experience. It is necessary to completely remove the tumor under endoscope, to expand resection of the dura and necrotic tissue around the leak, to repair the defect with multi-layer materials, to follow-up closely and to repair timely after operation.

[Association between urinary arsenic levels and anemia among older adults in nine longevity areas of China]

Objective: To investigate the association between urinary arsenic levels and anemia among older adults in nine longevity areas of China. Methods: A total of 1 896 subjects aged 65 years and above who participated in the Healthy Aging and Biomarkers Cohort Study (HABCS) in 2017-2018 were included. A self-made questionnaire was used to collect demographic characteristics, lifestyle and other information from the subjects. Through physical examination, data including height, weight and blood pressure were determined and body mass index (BMI) was calculated. Blood and urine samples were collected for the detection of hemoglobin (Hb), blood glucose, blood lipids, plasma vitamin B₁₂ and urinary arsenic concentrations. The urinary arsenic levels were divided into four groups according to the quartiles of urinary arsenic concentrations (μg/g creatinine): Q₁ (<18.7), Q₂ (18.7-34.5), Q₃ (34.6-69.5) and Q₄(≥69.6). Multivariate logistic regression model and restricted cubic spline fitting logistic regression model were used to analyze the association between urinary arsenic levels and anemia. Results: The age of the 1 896 subjects (M (Q₁, Q₃)) was 83 (74, 92) years, including 952 females (50.21%), and the concentration of Hb (M (Q₁, Q₃)) was 135 (124, 147)g/L. The prevalence of anemia was 24.89% (472 cases). The geometric mean and M (Q₁, Q₃) of urinary arsenic concentrations were 37.5 and 34.6 (18.7, 69.6)μg/g creatinine, respectively. Multivariate logistic regression model analysis showed that after adjusting for age, gender, BMI, education level, smoking and drinking status, residence, economic level, ethnicity, the status of vitamin B₁₂ deficiency, consumption frequency of aquatic products and meat, the prevalence of hypertension, diabetes and dyslipidemia, urinary arsenic levels were positively associated with anemia (Taking group Q₁ as a reference, OR (95%CI) values in Q₂, Q₃ and Q₄ groups were 1.73 (1.20-2.50), 2.08 (1.43-3.02) and 1.52 (1.02-2.28), respectively). The results of restricted cubic spline fitting logistic regression analysis showed a non-linear association between urinary arsenic concentrations and anemia (P<0.001). Subgroup analysis showed there was a negative multiplicative interaction between the prevalence of chronic diseases and urinary arsenic levels with OR (95%CI) was 0.55 (0.30-0.99), while no multiplicative interaction was found between age, gender, residence, smoking status, drinking status and urinary arsenic levels (P>0.05). There was a positive association between urinary arsenic levels and anemia in participants who were absence of chronic diseases,male, living in rural, smoking and drinking with OR (95%CI) values of 3.62 (1.30-10.06),2.46 (1.34-4.52), 1.70 (1.03-2.80), 2.21 (1.01-4.82) and 2.79 (1.23-6.33), respectively. Conclusion: There is a positive association between urinary arsenic levels and anemia among older adults in nine longevity areas of China.

[Prediction of 6-year risk of activities of daily living disability in elderly aged 65 years and older in China]

Objective: To construct an easy-to-use risk prediction tool for 6-year risk of activities of daily living(ADL) disability among Chinese elderly aged 65 and above. Methods: A total of 34 349 elderly aged 65 and above were recruited from the Chinese Longitudinal Healthy Longevity Survey. Demographic characteristics, lifestyle and chronic diseases of the elderly were collected through face-to-face interviews. The functional status of the elderly was evaluated by the instrumental activities of daily living(IADL) scale. The mental health status of the elderly was evaluated by the Mini-Mental State Examination. The height, weight, blood pressure and other information of the subjects were obtained through physical examination and body mass index(BMI) was calculated. The ADL status was evaluated by Katz Scale at baseline and follow-up surveys. Taking ADL status as the dependent variable and the key predictors were selected from Lasso regression as the independent variables, a Cox proportional risk regression model was constructed and visualized by the nomogram tool. Area under the receiver operating characteristic curve(AUC) and calibration curve were used to evaluate the discrimination and calibration of the model. A total of 200 bootstrap resamples were used for internal validation of the model. Sensitivity analysis was used to evaluate the robustness of the model. Results: The M(Q₁, Q₃) of subjects' age as 86(75, 94) years old, of which 9 774(46.0%) were males. A total of 112 606 person-years were followed up, 4 578 cases of ADL disability occurred and the incidence density was 40.7/1 000 person-years. Cox proportional risk regression model analysis showed that older age, higher BMI, female, hypertension and history of cerebrovascular disease were associated with higher risk of ADL disability [HR(95%CI) were 1.06(1.05-1.06), 1.05(1.04-1.06), 1.17(1.10-1.25),1.07(1.01-1.13) and 1.41(1.23-1.62), respectively.]; Ethnic minorities, walking 1 km continuously, taking public transportation alone and doing housework almost every day were associated with lower risk of ADL disability [HR(95%CI): 0.71(0.62-0.80), 0.72(0.65-0.80), 0.74(0.68-0.82) and 0.69(0.64-0.74), respectively]. The AUC value of the model was 0.853, and the calibration curve showed that the predicted probability was highly consistent with the observed probability. After excluding non-intervening factors(age, sex and ethnicity), the AUC value of the model for predicting the risk of ADL disability was 0.779. The AUC values of 65-74 years old and 75 years old and above were 0.634 and 0.765, respectively. The AUC values of the model based on walking 1 km continuous and taking public transport alone in IADL and the model based on comprehensive score of IADL were 0.853 and 0.851, respectively. Conclusion: The risk prediction model of ADL disability established in this study has good performance and robustness.

CD8αα+T cells exert a pro-inflammatory role in patients with psoriasis

Background

Psoriasis is a common chronic inflammatory disease caused by excessive activation of CD4⁺T cells, including Th17, Th1 and Th22. The role of CD8⁺T cells in psoriasis pathogenesis remains poorly understood.

Aim

To identify the phenotype of CD8⁺T cells in patients with psoriasis and to investigate its role in the formation of lesions.

Methods

The phenotype of CD8⁺T cells in psoriatic lesions was detected by immunofluorescence staining. Flow cytometry was performed to detect their phenotype in peripheral blood. Thereafter, coculture of CD8αα⁺T cells with autogenous CD4⁺T cells was performed to investigate the function of CD8αα⁺T cells in patients with psoriasis. Finally, pro‐inflammatory factors produced by CD8αα⁺T cells were examined by immunofluorescence staining and flow cytometry.

Results

Compared to the CD8αβ⁺T cells, CD8αα⁺T cell infiltration in psoriatic lesions markedly increased. Moreover, epidermal CD8αα⁺T cells exhibited tissue‐resident memory T cells (T_RM) phenotypes and dermal CD8αα⁺T cells exhibited effector memory (T_EM) phenotypes in psoriatic lesions. Additionally, we found that CD8αα⁺T cells from patients with psoriasis did not express the markers of regulatory T cells and could promote the proliferation of CD4⁺T effector cells and produce interleukin‐17 and interferon‐γ.

Conclusions

Our findings demonstrate that CD8αα⁺T cells contribute to the pathogenesis of psoriasis by producing pro‐inflammatory factors.

Influence of surgical team activity on airborne bacterial distribution in the operating room with a mixing ventilation system: a case study at St. Olavs Hospital

BACKGROUND

Operating rooms (ORs) have strict requirements regarding cleanliness. While existing standards concerning the ventilation and staff guidelines are theoretically sufficient to subvert the threats posed by micro-organisms within the room, there exist potential sources of contamination due to human activity around the area. Studies exploring this influence of human activity on distribution of micro-organism contamination in ORs have relied on manual observations, or indirect methods such as number of door openings.

AIM

To utilize depth registration sensing technology to identify the activities of surgical staff and investigate their effect on the distribution of airborne micro-organism contamination in ORs.

METHODS

A mock surgical experiment was performed using a depth registration technique for the dynamic capturing of human presence and activity levels. Field measurements were carried out in one real OR to analyse its influence on the bacterial distribution in ORs with mixing ventilation system.

FINDINGS

Bacterial contamination levels tended to correlate with higher activity levels, albeit with some inconsistencies. The highest activity levels were around the surgical bed when the patient was placed, and around the instrument table during the surgical procedure. Locations with obstructions had the highest cfu densities, indicating that airflow patterns are important in such spaces.

CONCLUSION

Our activity monitoring methods demonstrate a novel means of studying the influences of human activities in hospital rooms.

[Clinical features of patients with retinocytoma]

Objective: To analyze the clinical features and fundus performance of patients with retinocytoma. Methods: Retrospective case series study. Ten patients (12 eyes) diagnosed with retinocytoma were enrolled in Department of Ophthalmology of Eye & ENT Hospital of Fudan University from January 2006 to December 2019. Clinical data were reviewed, including gender, age, initial symptoms, tumor size and location, fundus manifestations and regression patterns. Results: There were 7 males and 3 females aged from 5 to 39 years, with a median age of 14 years. Eight patients had unilateral retinocytoma, while 2 patients had bilateral retinocytoma. The most common complaints were strabismus (4 patients) and blurred vision (3 patients). The average maximum base diameter of the tumor was 5.70 mm (2.69 to 8.69 mm), and the average thickness was 2.28 mm (0.61 to 3.76 mm). Tumors in 12 eyes were all of a single focus, 5 in the posterior pole, 5 in the midperiphery and 2 in the periphery. Ophthalmoscopic features of retinocytoma included a translucent retinal mass in 10 eyes, a calcification mass in 11 eyes, with well-defined retinal pigment epithelial alteration in 12 eyes and a zone of chorioretinal atrophy in 6 eyes. The regression patterns were type 1 in 2 eyes, type 2 in 1 eye and type 3 in 9 eyes. The gene test showed RB1 mutation in 1 patient. During the average follow-up of 28.7 months, all of the tumors were stable without malignant transformation. Conclusions: Retinocytoma is a rare benign retinal tumor with characteristic fundus manifestations. Patients with retinocytoma should be monitored closely. (Chin J Ophthalmol, 2021, 57: 526-530).

Evaluation of pulmonary ventilation in COVID-19 patients using oxygen-enhanced three-dimensional ultrashort echo time MRI: a preliminary study

AIM

To evaluate the lung function of coronavirus disease 2019 (COVID-19) patients using oxygen-enhanced (OE) ultrashort echo time (UTE) MRI.

MATERIALS AND METHODS

Forty-nine patients with COVID-19 were included in the study. The OE-MRI was based on a respiratory-gated three-dimensional (3D) radial UTE sequence. For each patient, the percent signal enhancement (PSE) map was calculated using the expression PSE = (S_100% – S_21%)/S_21%, where S_21% and S_100% are signals acquired during room air and 100% oxygen inhalation, respectively. Agreement of lesion detectability between UTE-MRI and computed tomography (CT) was performed using the kappa test. The Mann–Whitney U-test was used to evaluate the difference in the mean PSE between mild-type COVID-19 and common-type COVID-19. Spearman's test was used to assess the relationship between lesion mean PSE and lesion size. Furthermore, the Mann–Whitney U-test was used to evaluate the difference in region of interest (ROI) mean PSE between normal pulmonary parenchyma and lesions. The Kruskal–Wallis test was applied to test the difference in the mean PSE between different lesion types.

RESULTS

CT and UTE-MRI reached good agreement in lesion detectability. Ventilation measures in mild-type patients (5.3 ± 5.5%) were significantly different from those in common-type patients (3 ± 3.9%). Besides, there was no significant correlation between lesion mean PSE and lesion size. The mean PSE of COVID-19 lesions (3.2 ± 4.9%) was significantly lower than that of the pulmonary parenchyma (5.4 ± 3.9%). No significant difference was found among different lesion types.

CONCLUSION

OE-UTE-MRI could serve as a promising method for the assessment of lung function or treatment management of COVID-19 patients.

Acetaminophen Inhibits the Neutrophil Oxidative Burst: Implications for Diagnostic Testing

BACKGROUND

Chronic granulomatous disease is a primary immunodeficiency characterized by recurrent bacterial and fungal infections, granuloma formation, and inflammatory disease. Impaired neutrophil oxidative function is an essential diagnostic criterion. In vitro exposure of neutrophils to acetaminophen, a commonly used over-the-counter medication, has been associated with reduced neutrophil oxidative function. The clinical implications of acetaminophen intake for dihydrorhodamine (DHR) testing remain unknown.

OBJECTIVE

To evaluate the effect of in vivo administration of therapeutic doses of acetaminophen on DHR diagnostic testing.

METHODS

We performed DHR testing in 15 healthy adults before and after administering a single dose of acetaminophen. We retrospectively reviewed 195 DHR test results from hospitalized patients who had received acetaminophen, nonsteroidal anti-inflammatory drug, or corticosteroid before testing.

RESULTS

DHR testing result was abnormal in 100% (n = 15) of healthy adults 2 hours after acetaminophen intake. We identified 195 instances of DHR testing less than or equal to 72 hours after acetaminophen ingestion in hospitalized patients who did not have chronic granulomatous disease. DHR results were abnormal in 43 of 195 cases (22.1%). Frequency of false-positive testing was increased in patients who received acetaminophen within 24 hours of testing, and in patients who received more than 1 dose of acetaminophen. Nonsteroidal anti-inflammatory drug and corticosteroid intakes were not associated with abnormal DHR result.

CONCLUSIONS

Patients treated with acetaminophen have decreased neutrophil oxidative burst as measured by DHR testing. To avoid falsely abnormal testing for chronic granulomatous disease, patients should be advised to avoid acetaminophen for at least 24 hours before DHR testing.

Biosynthesis of poly-γ-glutamic acid in Escherichia coli by heterologous expression of pgsBCAE operon from Bacillus

AIMS

Poly-γ-glutamic acid (γ-PGA) is an excellent water-soluble biosynthesis material. To confirm the rate-limiting steps of γ-PGA biosynthesis pathway, we introduced a heterologous Bacillus strain pathway and employed an enzyme-modulated dismemberment strategy in Escherichia coli.

METHODS AND RESULTS

In this study, we heterologously introduced the γ-PGA biosynthesis pathway of two laboratory-preserved strains-Bacillus amyloliquefaciens FZB42 and Bacillus subtilis 168 into E. coli, and compared their γ-PGA production levels. Next, by changing the plasmid copy numbers and supplying sodium glutamate, we explored the effects of gene expression levels and concentrations of the substrate l-glutamic acid on γ-PGA production. We finally employed a two-plasmid induction system using an enzyme-modulated dismemberment of pgsBCAE operon to confirm the rate-limiting genes of the γ-PGA biosynthesis pathway.

CONCLUSION

Through heterologously over-expressing the genes of the γ-PGA biosynthesis pathway and exploring gene expression levels, we produced 0·77 g l^-1 γ-PGA in strain RSF-EBCAE(BS). We also confirmed that the rate-limiting genes of the γ-PGA biosynthesis pathway were pgsB and pgsC.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work is beneficial to increase γ-PGA production and study the mechanism of γ-PGA biosynthesis enzymes.

[A phase Ⅰ dose-escalating trial of pegylated liposomal doxorubicin in combination with cyclophosphamide, vincristine and prednisone for aggressive non-Hodgkin lymphoma]

Objective: To explore the maximum tolerated dose of pegylated liposomal doxorubicin (PLD) in combination with cyclophosphamide, vincristine and prednisone as a modified CHOP regimen for aggressive non-Hodgkin lymphoma. Methods: Patients with newly diagnosed aggressive non-Hodgkin lymphoma were eligible for this trial. PLD was administered in cycle 1 and categorized into 4 dose level (30 mg/m², 35 mg/m², 40 mg/m², 45 mg/m² D1) according to a 3 + 3 approach for dose-escalation. Doxorubin was used in cycles 2-6. In this combination regimen, the doses of cyclophosphamide (750 mg/m² D1), vincristine (1.4 mg/m² D1, maximum dose of 2 mg) and prednisone (100 mg D1-5) were fixed. Toxicities of cycle 1 were documented. Results: Totally, 21 patients were enrolled in this trial. Among them, 15 patients had T-cell lymphoma and 6 had B-cell lymphoma. When the dose of PLD was escalated to the level of 45 mg/m², 2 of 3 patients developed grade 3 mucositis, which met the criteria of dose-limiting toxicity. Therefore, the dose was de-escalated for one level. At the level of 40 mg/m², only one among 12 patients had pneumonia and grade 4 neutropenia. In all dose levels, the grade 3/4 toxicities observed were neutropenia (13 cases, 61.9% ), mucositis (2 cases, 9.5% ), thrombocytopenia (1 case, 4.8%) and pneumonia (1 case, 4.8%). Conclusion: When combined with cyclophosphamide, vincristine and prednisone as a combination regimen, the maximum tolerated dose of PLD was 40 mg/m².

MiR-21 enhanced glioma cells resistance to carmustine via decreasing Spry2 expression

OBJECTIVE

Gliomas are accompanied with high mortality owning to their invasive peculiarity and vulnerability to drug resistance. miR-21 is a vital oncogenic miRNA that regulates drug resistance of tumor cells. This study aims to elucidate the function of miR-21 in human glioma cells resistant to carmustine (BCNU) and to demonstrate the underlying molecular mechanism.

MATERIALS AND METHODS

BCNU-sensitive cells (SWOZ2 cells) were transfected with miR-21 agomir and negative control, and BCNU-resistance cells (SWOZ2-BCNU cells) were transfected with miR-21 antagomir and negative control. The Real-time fluorescence quantitative PCR was used to detect and compare the levels of miR-21expression between SWOZ2-BCNU and SWOZ2 cells. The drug sensitivity of these cells to BCNU was determined by Cell Counting Kit-8 (CCK-8) assay. The protein expression of Spry2 was detected by Western blotting.

RESULTS

The expression level of miR-21 was remarkably higher in SWOZ2-BCNU cells than that in SWOZ2 cells. The half-maximal inhibitory concentration (IC50) of BCNU was obviously higher for SWOZ2-BCNU cells than that for SWOZ2 cells. Besides, we found that aberrant expression of miR-21 in SWOZ2-BCNU cells is responsible for glioma BCNU-resistance. Consistently, Spry2 protein levels were significantly reduced in SWOZ2-BCNU as well as in miR-21 agomir-transfected cells, inversely correlated to miR-21 expression. The results of si-Spry2 co-transfection suggested that the effect of miR-21 on glioma BCNU-resistance is mediated through Spry2.

CONCLUSIONS

miR-21 enhances the resistance of human glioma cells to BCNU by decreasing the expression of Spry2 protein. Thus, Spry2 may be a novel therapeutic target for treating glioma BCNU-resistance.

First-in-human study of the safety and viability of intraocular robotic surgery

Microsurgery of the retina would be dramatically improved by instruments that offer supra-human precision. Here, we report the results of a first-in-human study of remotely controlled robot-assisted retinal surgery performed through a telemanipulation device. Specifically, 12 patients requiring dissection of the epiretinal or inner limiting membrane over the macula were randomly assigned to either undergo robot-assisted-surgery or manual surgery, under general anaesthesia. We evaluated surgical success, duration of surgery and amount of retinal microtrauma as a proxy for safety. Surgical outcomes were equally successful in the robotic-surgery and manual-surgery groups. Differences in the amount of retinal microtrauma between the two groups were statistically insignificant, yet dissection took longer with robotic surgery (median time, 4 min 5 s) than with manual surgery (1 min 20 s). We also show the feasibility of using the robot to inject recombinant tissue plasminogen activator under the retina to displace sight-threatening haemorrhage in three patients under local anaesthesia. A safe and viable robotic system for intraocular surgery would enable precise and minimally traumatic delivery of gene therapy or cell therapy to the retina.

Mechanism of As2O3 induces apoptosis of glioma U87 cells

OBJECTIVE

To investigate the mechanism of arsenic trioxide (As2O3)-induced apoptosis of glioma cells.

MATERIALS AND METHODS

U87 cells were treated by different concentrations of As2O3 (8 μmol/L, 6 μmol/L, 4 μmol/L, 2 μmol/L, 1 μmol/L and 0.5 μmol/L) for 24 h, 48 h and 72 h, respectively. Cell viability was detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the appropriate dosage and time were screened. Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) was used to stain cells, followed by an investigation on the apoptosis of cells. In the study of molecular mechanism, the expression of p53 in the cells was determined by immunofluorescence, and then apoptosis-related factors, Fas, FasL and Bax, were tested using Real-time polymerase chain reaction (RT-PCR). Finally, the effect of As2O3 on apoptosis-related proteins, caspase-3 and caspase-9, was investigated by Western blotting.

RESULTS

As2O3 could significantly inhibit proliferation of U87 cells, and the result of TUNEL staining displayed As2O3 had the function of inducing apoptosis. Immunofluorescence results demonstrated that p53 was highly expressed in glioma cells, which was reduced after drug administration. The results of detection of apoptosis factors using RT-PCR revealed that mRNA expressions of Fas, FasL and Bax in the glioma cells were distinctly higher than those in the As2O3 group. The result of Western blotting indicated that caspase-3 and caspase-9 proteins were highly expressed in glioma cells. Analysis of variance showed that the difference between the control group and the As2O3 group was statistically significant (p<0.01).

CONCLUSIONS

As2O3 can inhibit proliferation of glioma cells and induce its apoptosis, which may be correlated with down-regulation of expressions of apoptosis-related factors, Fas, FasL and Bax, and apoptosis-related proteins, p53, caspase-3 and caspase-9.

[Clinical research on immune checkpoint and head and neck squamous cell carcinoma]

T cell immune checkpoint pathways contribute to tumor immune escape. Many studies have shown that immune checkpoint is demonstrably correlated with tumor grade or prognosis in several types of malignancies and immune checkpoint has become a new biological index for tumor detection and prognosis. Immune checkpoint inhibitors have shown promising tumor outcomes in clinical trials for some advanced solid tumors and it will become a new target for cancer immunotherapy. In this review we will explore the correlation between expressions of immune checkpoint-associated genes and proteins in immune microenviroment and prognosis of head and neck squamous cell carcinoma, and specifically will discuss how this pathway can be manipulated with immune therapeutic drugs.

Technique of retinal gene therapy: delivery of viral vector into the subretinal space

PurposeSafe and reproducible delivery of gene therapy vector into the subretinal space is essential for successful targeting of the retinal pigment epithelium (RPE) and photoreceptors. The success of surgery is critical for the clinical efficacy of retinal gene therapy. Iatrogenic detachment of the degenerate (often adherent) retina in patients with hereditary retinal degenerations and small volume (eg, 0.1 ml) subretinal injections pose new surgical challenges.MethodsOur subretinal gene therapy technique involved pre-operative planning with optical coherence tomography (OCT) and autofluorescence (AF) imaging, 23 G pars plana vitrectomy, internal limiting membrane staining with Membrane Blue Dual (DORC BV, Zuidland, Netherlands), a two-step subretinal injection using a 41 G Teflon tipped cannula (DORC) first with normal saline to create a parafoveal bleb followed by slow infusion of viral vector via the same self-sealing retinotomy. Surgical precision was further enhanced by intraoperative OCT (Zeiss Rescan 7000, Carl Zeiss Meditec AG, Jena, Germany). Foveal functional and structural recovery was evaluated using best-corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity, microperimetry and OCT.ResultsTwo patients with choroideremia aged 29 (P1) and 27 (P2) years, who had normal and symmetrical levels of best-corrected visual acuity (BCVA) in both eyes, underwent unilateral gene therapy with the fellow eye acting as internal control. The surgeries were uncomplicated in both cases with successful detachment of the macula by subretinal vector injection. Both treated eyes showed recovery of BCVA (P1: 76-77 letters; P2: 84-88 letters) and mean threshold sensitivity of the central macula (P1: 10.7-10.7 dB; P2: 14.2-14.1 dB) to baseline within a month. This was accompanied by normalisation of central retinal thickness on OCT.ConclusionsHerein we describe a reliable technique for subretinal gene therapy, which is currently used in clinical trials to treat choroideremia using an adeno-associated viral (AAV) vector encoding the CHM gene. Strategies to minimise potential complications, such as avoidance of excessive retinal stretch, air bubbles within the injection system, reflux of viral vector and post-operative vitritis are discussed.

[Short-term efficacy of intravitreal injection of melphalan for refractory vitreous seeding from retinoblastoma]

Objective: To evaluate the efficacy and safety of intravitreal chemotherapy for refractory vitreous seeding from retinoblastoma. Methods: Retrospective series of case studies. Nine patients (13 eyes) with the diagnosis of refractory vitreous seeding were enrolled in Department of Ophthalmology of Eye& ENT Hospital of Fudan University from March 2014 to October 2015.There were 6 males and 3 females. Children aged 8 to 40 months, median age of 18 months. In the 13 eyes, 3 eyes were E period, 9 eyes were D period, and 1 eyes were C period. The fundus was examined by indirect ophthalmoscope and recorded by RetcamIII. Systemic chemotherapy was performed using the VEC protocol, that is vincristine, etoposide, and carboplatin. Local treatment also involves cryotherapy and/or thermotherapy. All patients were treated with intravitreal injection of melphalan. They underwent intravitreal melphalan, once every 4 weeks, with an average of 3 times of injections. The treatment dose of melphalan is 20 to 40 μg per dose. Observe the vitreous seed control and complications of therapy. Results: Vitreous seeds control was attained in all cases. There was no case of orbital extension or remote metastasis. Complications included retinal pigment epithelial and choroidal atrophy in 7 eyes, pupillary synechia and iris atrophy in 2 eyes,retinal vasculitis and vascular occlusion in 2 eyes, optic atrophy in 2 eyes, vitreous hemorrhage in 1 eye, and temporary hypotony in 3 eyes. Conclusions: Intravitreal melphalan is an effective treatment for refractory vitreous seeding from retinoblastoma. High dose may lead to local adverse reactions. (Chin J Ophthalmol, 2017, 53: 570-574).

[Eyeball salvage treatment or enucleation for advanced retinoblastoma]

The management of retinoblastoma (RB) has dramatically changed over the past two decades. The introduction of chemotherapy has transformed treatment algorithms completely. Chemotherapy is currently used as a first line approach for children with RB and can be delivered by intravenous, intra-arterial and intravitreal routes. However, there still remains some controversy on the treatment of advanced RB, especially in eyeball salvage. This article described domestic and international approaches to eyeball salvage treatment. We would like to further discuss our opinion on the management of advanced RB based on our clinical experience for attracting more clinical concern on this issue. Many factors should be considered when choosing the appropriate conservative therapy. The choice of eyeball salvage treatment not only depends upon the tumor staging and laterality but also upon compliance and economic factors. Doctors and parents should not blindly pursue eye saving. However, there are still cases where enucleation is definitely the treatment of choice. (Chin J Ophthalmol, 2016, 52: 728-732).

Formation mechanism of shock-induced particle jetting

The shock dissemination of granular rings or shells is characterized by the formation of coherent particle jets that have different dimensions from those associated with the constituent grains. In order to identify the mechanisms governing the formation of particle jets, we carry out the simulations of the shock dispersal of quasi-two-dimensional particle rings based on the discrete-element method. The evolution of the particle velocities and contact forces on the time scales ranging from microseconds to milliseconds reveals a two-stage development of particle jets before they are expelled from the outer surface. Much effort is made to understand the particle agglomeration around the inner surface that initiates the jet formation. The shock interaction with the innermost particle layers generates a heterogeneous network of force chains with clusters of strong contacts regularly spaced around the inner surface. Momentum alongside the stresses is primarily transmitted along the strong force chains. Therefore, the clustering of strong force chains renders the agglomeration of fast-moving particles connected by strong force chains. The fast-moving particle clusters subsequently evolve into the incipient particle jets. The following competition among the incipient jets that undergo unbalanced growth leads to substantial elimination of the minor jets and the significant multiplication of the major jets, the number of jets thus varying with time. Moreover, the number of jets is found to increase with the strength of the shock loading due to an increased number of jets surviving the retarding effect of major jets.

Management with willow short rotation coppice increase the functional gene diversity and functional activity of a heavy metal polluted soil

We studied the microbial functional diversity, biochemical activity, heavy metals (HM) availability and soil toxicity of Cd, Pb and Zn contaminated soils, kept under grassland or short rotation coppice (SRC) to attenuate the risks associated with HM contamination and restore the soil ecological functions. Soil microbial functional diversity was analyzed by the GeoChip, a functional gene microarray containing probes for genes involved in nutrient cycling, metal resistance and stress response. Soil under SRC showed a higher abundance of microbial genes involved in C, N, P and S cycles and resistance to various HM, higher microbial biomass, respiration and enzyme activity rates, and lower HM availability than the grassland soil. The linkages between functional genes of soil microbial communities and soil chemical properties, HM availability and biochemical activity were also investigated. Soil toxicity and N, P and Pb availability were important factors in shaping the microbial functional diversity, as determined by CCA. We concluded that in HM contaminated soils the microbial functional diversity was positively influenced by SRC management through the reduction of HM availability and soil toxicity increase of nutrient cycling. The presented results can be important in predicting the long term environmental sustainability of plant-based soil remediation.

Rapid atraumatic sex identification of developmental day 14-16 mice

Embryonic mice have been used widely to study organ development. Days 14-16 are critical for sex organ development and differentiation in mice. Current methods for sex identification are limited. Even the simplest polymerase chain reaction method may injure the embryo. We determined that morphologic analysis of embryonic mammary anlagen could be used for rapid atraumatic sex identification of day 14-16 mice. The accuracy of our method was verified by molecular and anatomical approaches.

Lithography and doping in strained Si towards atomically precise device fabrication

We investigate the ability to introduce strain into atomic-scale silicon device fabrication by performing hydrogen lithography and creating electrically active phosphorus δ-doped silicon on strained silicon-on-insulator (sSOI) substrates. Lithographic patterns were obtained by selectively desorbing hydrogen atoms from a H resist layer adsorbed on a clean, atomically flat sSOI(001) surface with a scanning tunnelling microscope tip operating in ultra-high vacuum. The influence of the tip-to-sample bias on the lithographic process was investigated allowing us to pattern feature-sizes from several microns down to 1.3 nm. In parallel we have investigated the impact of strain on the electrical properties of P:Si δ-doped layers. Despite the presence of strain inducing surface variations in the silicon substrate we still achieve high carrier densities (>1.0 × 10(14) cm(-2)) with mobilities of ∼100 cm(2) V(-1) s(-1). These results open up the possibility of a scanning-probe lithography approach to the fabrication of strained atomic-scale devices in silicon.