The environmental and socioeconomic effects of tuberculosis patients in the southwest of China: a population-based study.

OBJECTIVE: The objective of this study was to assess the incidence of tuberculosis (TB) and find the risk factors of TB patients with a high burden of TB in socioeconomic level, the high level of TB incidence and the great changes of economic and social factors, explore the possible factors, construct scientific and robust prediction model, and analyse whether the task of stopping TB can be accomplished by the expected global deadline. STUDY DESIGN: This was an ecological study. METHODS: Descriptive analysis, spatial and space-time scan, correlation analysis, and regression analysis were carried out, based on cases of TB in Sichuan Province and ecological data from 2006 to 2017, to explore the characters of TB and ecological factors, using the transfer function-noise model to forecast the trend of TB until 2035. RESULTS: Factors affecting the incidence of TB, increasing per capita green area, reporting status of TB among Tibetans and Yi minorities, comprehensive treatment management, total cost of TB per capita for urban residents, proportion of males with high school education, 20 to 20 h of 24-h accumulated precipitation, reducing HIV at the same time as AIDS deaths, the increase in the proportion of males in junior high school education, and the increase in the number of registered TB cases can reduce the incidence of TB. CONCLUSIONS: There was concentration mainly on enhanced control of the environment and society measures, helpful in guiding government planning to control TB. Reinforcement is required to reduce the TB of population aged 15-24 and aged 25-64 in socioeconomic level by 2035.

[Pelvic exenteration for late complications of radiation-induced pelvic injury: a preliminary study].

Objective: To investigate the safety and efficacy of total pelvic exenteration (TPE) for treating late complications of radiation-induced pelvic injury. Methods: This was a descriptive case series study. The inclusion criteria were as follows: (1) confirmed radiation-induced pelvic injury after radiotherapy for pelvic malignancies; (2) late complications of radiation-induced pelvic injury, such as bleeding, perforation, fistula, and obstruction, involving multiple pelvic organs; (3) TPE recommended by a multidisciplinary team; (4) patient in good preoperative condition and considered fit enough to tolerate TPE; and (5) patient extremely willing to undergo the procedure and accept the associated risks. The exclusion criteria were as follows: (1) preoperative or intraoperative diagnosis of tumor recurrence or metastasis; (2) had only undergone diversion or bypass surgery after laparoscopic exploration; and (3) incomplete medical records. Clinical and follow-up data of patients who had undergone TPE for late complications of radiation-induced pelvic injury between March 2020 and September 2022 at the Sixth Affiliated Hospital of Sun Yat-sen University were analyzed. Perioperative recovery, postoperative complications, perioperative deaths, and quality of life 1 year postoperatively were recorded. Results: The study cohort comprised 14 women, nine of whom had recto-vagino-vesical fistulas, two vesicovaginal fistulas, one ileo-vesical fistula and rectal necrosis, one ileo-vesical and rectovaginal fistulas, and one rectal ulcer and bilateral ureteral stenosis. The mean duration of surgery was 592.1±167.6 minutes and the median blood loss 550 (100-6000) mL. Ten patients underwent intestinal reconstruction, and four the Hartmann procedure. Ten patients underwent urinary reconstruction using Bricker's procedure and 7 underwent pelvic floor reconstruction. The mean postoperative hospital stay was 23.6±14.9 days. Seven patients (7/14) had serious postoperative complications (Clavien-Dindo IIIa to IVb), including surgical site infections in eight, abdominopelvic abscesses in five, pulmonary infections in five, intestinal obstruction in four, and urinary leakage in two. Empty pelvis syndrome (EPS) was diagnosed in five patients, none of whom had undergone pelvic floor reconstruction. Five of the seven patients who had not undergone pelvic floor reconstruction developed EPS, compared with none of those who had undergone pelvic floor reconstruction. One patient with EPS underwent reoperation because of a pelvic abscess, pelvic hemorrhage, and intestinal obstruction. There were no perioperative deaths. During 18.9±10.1 months of follow-up, three patients died, two of renal failure, which was a preoperative comorbidity, and one of COVID-19. The remaining patients had gradual and significant relief of symptoms during follow-up. QLQ-C30 assessment of postoperative quality of life showed gradual improvement in all functional domains and general health at 1, 3, and 6 months postoperatively (all P<0.05). Conclusions: TPE is a feasible procedure for treating late complications of radiation-induced pelvic injury combined with complex pelvic fistulas. TPE is effective in alleviating symptoms and improving quality of life. However, the indications for this procedure should be strictly controlled and the surgery carried out only by experienced surgeons.

Characteristics of flight delays during solar flares.

Solar flares are one of the severest solar activities that have important effects on near-Earth space. Previous studies have shown that flight arrival delays increase as a result of solar flares, but the intrinsic mechanism behind this relationship is still unknown. In this study, we conducted a comprehensive analysis of flight departure delays during 57 solar X-ray events by using a huge amount of flight data (~ 5 × 106 records) gathered over a 5-year period. It is found that the average flight departure delay time during solar X-ray events increased by 20.68% (7.67 min) compared to quiet periods. Our analysis also revealed apparent time and latitude dependencies, with flight delays being more serious on the dayside than on the nightside and longer (shorter) delays tending to occur in lower (higher) latitude airports during solar X-ray events. Furthermore, our results suggest that the intensity of solar flares (soft X-ray flux) and the Solar Zenith Angle directly modulate flight departure delay time and delay rate. These results indicate that communication interferences caused by solar flares directly affect flight departure delays. This work expands our conventional understanding of the impacts of solar flares on human society and provides new insights for preventing or coping with flight delays.

[Clincal practice of pelvic exenteration for late complications of pelvic radiation injury].

Pelvic radiation injury can potentially involve multiple pelvic organs, and due to its progressive and irreversible nature, its late stage can be complicated by fistulas, perforations, obstructions and other complications involved multiple pelvic organs, which seriously affect the long-term survival and the quality of life of patients. As a multidisciplinary surgical approach, pelvic exenteration has potential application in the treatment of late complications of pelvic radiation injury by completely removing the irradiated lesion, relieving symptoms and avoiding recurrence of symptoms. In clinical practice, we should advocate the concept of "pelvic radiation injury", emphasize multidisciplinary collaboration, fully evaluate the overall status of patients, primary tumor and pelvic radiation injury. We should follow the principles of "damage-control" and "extended resection", and follow the principle of enhanced recovery after surgery to achieve the goal of ensuring the surgical safety, relieving patients' symptoms and improving patients' quality of life and long-term survival.

Additional flight delays and magnetospheric-ionospheric disturbances during solar storms.

Although the sun is really far away from us, some solar activities could still influence the performance and reliability of space-borne and ground-based technological systems on Earth. Those time-varying conditions in space caused by the sun are also called solar storm or space weather. It is known that aviation activities can be affected during solar storms, but the exact effects of space weather on aviation are still unclear. Especially how the flight delays, the top topic concerned by most people, will be affected by space weather has never been thoroughly researched. By analyzing huge amount of flight data (~ 4 × 106 records), for the first time, we quantitatively investigate the flight delays during space weather events. It is found that compared to the quiet periods, the average arrival delay time and 30-min delay rate during space weather events are significantly increased by 81.34% and 21.45% respectively. The evident negative correlation between the yearly flight regularity rate and the yearly mean total sunspot number during 22 years also confirms such correlation. Further studies show that the flight delay time and delay rate will monotonically increase with the geomagnetic field fluctuations and ionospheric disturbances. These results indicate that the interferences in communication and navigation during space weather events may be the most probable reason accounting for the increased flight delays. The above analyses expand the traditional field of space weather research and could also provide us with brand new views for improving the flight delay predications.

[Bowel preparation before elective surgery for colorectal cancer].

For elective surgery of colorectal cancer, current evidence supports preoperative mechanical bowel preparation combined with oral antibiotics. Meanwhile, for patients with varied degrees of intestinal stenosis, individualized protocol is required to avoid adverse events. We hereby summarize recent high-quality evidences and updates of guidelines and consensus, and recommend stratified bowel preparation based on the clinical practice of our institute as follows. (1) For patients with unimpaired oral intake, whose tumor can be passed by colonoscopy, mechanical bowel preparation and oral antibiotics are given. (2) For patients without symptoms of bowel obstruction but with impaired oral intake or incomplete colonoscopy due to tumor-related stenosis, small-dosage laxative is given for several days before surgery, and oral antibiotics the day before surgery. (3) For patients with bowel obstruction, mechanical bowel preparation or enema is not indicated. We proposed this evidence-based, individualized protocol for preoperative bowel preparation for the reference of our colleagues, in the hope of improving perioperative outcomes and reducing adverse events.

Infants' developing sensitivity to native language phonotactics: A meta-analysis.

We used Bayesian modeling to aggregate experiments investigating infants' sensitivity to native language phonotactics. Our findings were based on data from 83 experiments on about 2000 infants learning 8 languages, tested using 4 different methods. Our results showed that, unlike with artificial languages, infants do exhibit sensitivity to native language phonotactic patterns in a lab setting. However, the exact developmental trajectory depends on the phonotactic pattern being tested. Before 8 months, infants tuned into non-local dependencies between vowels: specifically, vowel harmony. Between 8- and 10-months, infants demonstrated a consistent sensitivity to both local dependencies and non-local consonant dependencies. Sensitivity to non-local vowel dependencies that are not based on harmony emerged only after 10-months. These findings provide a benchmark for future experimental and computational research on the acquisition of phonotactics.

[Meta analysis of diseased bowel resection versus diversion enterostomy in the treatment of late severe complications of chronic radiation-induced rectal injury].

Objective: To investigate the efficacy and safety of diseased bowel resection and diversion enterostomy in the treatment of late severe complications of chronic radiation-induced late rectal injury (RLRI). Methods: Studies about comparison of diseased bowel resection and diversion enterostomy in the treatment of late severe complications of chronic RLRI were screened and retrieved from databases, including PubMed, EMBASE, Scopus, Web of Science, Cochrane Library, CNKI, VIP, CBM and Wanfang. The following terms in Chinese were used to search [Title/Abstract]: radiation-induced intestinal injury, radiation proctitis, surgery. The following English terms were used to search: Radiation-induced intestinal injury, Bowel injury from radiation, Radiation proctitis, Surgery, Colostomy. Literature inclusion criteria: (1) studies with control groups, published at home and abroad publicly, about the postoperative effects of diseased bowel resection vs. diversion enterostomy on RLRI patients with late severe complications; (2) the period of the study performed in the literatures must be clear; (3) patients at the preoperative diagnosis for RLRI with refractory bleeding, narrow, obstruction, perforation or fistula, etc.; (4) diseased bowel resection included Hartmann, Dixon, Bacon and Parks; diversion enterostomy included colostomy and ileostomy; (5) if the studies were published by the same institution or authors at the same time, the study with the biggest sample size was chosen; studies conducted in different time with different subjects were simultaneously included; (6) at least one prognostic indicator of the following parameters should be included: the improvement of symptoms, postoperative complications, mortality, and reversed stomas rate. The stoma reduction rate was defined as the ratio of successful closure of colostomy after diseased bowel resection and diversion enterostomy. The method of direct calculation or the method of convert into direct calculation were used for stoma reduction rate. Exclusion criteria: (1) a single-arm study without control group; (2) RLRI patients did not undergo diseased bowel resection or diversion enterostomy at the first time; (3) RLRI patients with distant metastasis; (4) the statistical method in the study was not appropriate; (5) the information was not complete, such as a lack of prognosis in the observational indexes. After screening literatures according to criteria, data retrieval and quality evaluation were carried out. Review Manager 5.3 software was used for Meta-analysis. Sensitivity analysis was used to exam the stability of results. Funnel diagram was used to analyze the bias of publication. Results: A total of 11 literatures were enrolled, including 426 RLRI patients with late severe complications, of whom 174 underwent diseased bowel resection (resection group) and 252 underwent diversion enterostomy (diversion group), respectively. Compared with diversion group, although resection group had a higher morbidity of complication (35.1% vs. 15.9%, OR=2.67, 95% CI: 1.58 to 4.53, P<0.001), but it was more advantageous in symptom improvement (94.2% vs. 64.1%, OR=6.19, 95% CI: 2.47 to 15.52, P<0.001) and stoma reductions (62.8% vs. 5.1%, OR=15.17, 95% CI: 1.21 to 189.74, P=0.030), and the differences were significant (both P<0.05). No significant difference in postoperative mortality was found between the two groups (10.1% vs. 18.8%, OR=0.74, 95% CI: 0.21 to 2.59, P=0.640). There were no obvious changes between the two groups after sensitivity analysis for the prognostic indicators (the symptoms improved, postoperative complications, mortality, and reversed stomas rate) compared with the meta-analysis results before exclusion, suggesting that the results were robust and credible. Funnel diagram analysis suggested a small published bias. Conclusions: Chronic RLRI patients with late severe complications undergoing diseased bowel resection have higher risk of complication, while their long-term mortality is comparable to those undergoing diversion enterostomy. Diseased bowel resection is better in postoperative improvement of symptoms and stoma reduction rate.

An update on the status of COVID-19: a comprehensive review.

The last two decades have witnessed two large-scale pandemics caused by coronaviruses, including severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS). At the end of 2019, another novel coronavirus, designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), hit Wuhan, a city in the center of China, and subsequently spread rapidly to the whole world. Latest reports revealed that more than 800 thousand people in over 200 countries are involved in the epidemic disease by SARS-CoV-2. Due to the high mortality rate and the lack of optimum therapeutics, it is crucial to understand the biological characteristics of the virus and its possible pathogenesis to respond to the SARS-CoV-2. Rapid diagnostics and effective therapeutics are also important interventions for the management of infection control. However, the rapid evolution of SARS-CoV-2 exerted tremendous challenges on its diagnostics and therapeutics. Therefore, there is an urgent need to summarize the existing research results to guide decision-making on the prioritization of resources for research and development. In this review, we focus on our current understanding of epidemiology, pathogenesis, diagnostics and therapeutics of coronavirus disease 2019 (COVID-19).

Measurement of the Vector and Tensor Asymmetries at Large Missing Momentum in Quasielastic (e[over →],e

We report the measurement of the beam-vector and tensor asymmetries A_{ed}^{V} and A_{d}^{T} in quasielastic (e[over →],e^{'}p) electrodisintegration of the deuteron at the MIT-Bates Linear Accelerator Center up to missing momentum of 500 MeV/c. Data were collected simultaneously over a momentum transfer range 0.1

Actin cytoskeleton stiffness grades metastatic potential of ovarian carcinoma Hey A8 cells via nanoindentation mapping.

Recent studies have indicated that the nanoindentation measured stiffness of carcinoma adherent cells is in general lower than normal cells, thus suggesting that cell stiffness may serve as a bio-marker for carcinoma. However, the proper establishment of such a conclusion would require biophysical understanding of the underlying mechanism of the cell stiffness. In this work, we compared the elastic moduli of the actin cytoskeletons of Hey A8 ovarian carcinoma cells with and without metastasis (HM and NM), as measured by 2D atomic force microscopy (AFM) with low-depth nanoindentation via a rate-jump method. The results indicate clearly that HM cells showed lower actin cytoskeleton stiffness atop of their nucleus position and higher actin cytoskeleton stiffness at their rims, compared to NM cells, suggesting that the local stiffness on the cytoskeleton can reflect actin filament distribution. Immunofluorescence staining and scanning electron microscopy (SEM) also indicated that the difference in stiffness in Hey A8 cells with different metastasis is associated with their F-actin rearrangement. Finite-element modelling (FEM) shows that a migrating cell would have its actin filaments bundled together to form stress fibers, which would exhibit lower indentation stiffness than the less aligned arrangement of filaments in a non-migrating cell. The results here indicate that the actin cytoskeleton stiffness can serve as a reliable marker for grading the metastasis of adherent carcinoma cells due to their cytoskeleton change and potentially predicting the migration direction of the cells.

Bone characteristics, histopathology, and chondrocyte apoptosis in femoral head necrosis induced by glucocorticoid in broilers.

Femoral head necrosis (FHN) is a common disorder in fast-growing broilers in the poultry industry, but the pathogenesis of FHN has not been clarified completely. In the present study, glucocorticoid (GC) administration was used to induce FHN in broilers. Compared with normal birds, histopathology showed that the length of the articular cartilage of GC-induced FHN broilers was thicker while the proliferative zone and prehypertrophic zone were obviously thinner. Moreover, hematoxylin and eosin (HE) staining showed the apoptotic chondrocyte in the growth plate of the femoral head in FHN-affected birds. Bone parameters also decreased significantly in GC-induced FHN broilers. In addition, as for the mRNA expression, GC-induced FHN broilers had an apparent reduction in Col-II, Col-X, and Bcl-2 but a significant promotion of Caspase-3, Caspase-9, ASK-1, and JNK-1 when compared with the normal birds. It showed glucocorticoid induced FHN in broilers by affecting the proliferation, differentiation, and apoptosis of chondrocytes accompanying the retarding of bone growth.

Expanding public health in China: an empirical analysis of healthcare inputs and outputs.

OBJECTIVES: The Chinese Government claims that China's health policy is primarily focused on prevention. However, this does not appear to be the case. Researchers with an interest in China's health policy may be aware that the Chinese Government launched a health reform in 2009 to improve the health status of the entire population by 2020.1 This health reform has been in place for 7 years, and only 4 years now remain to achieve the overall objectives by 2020. This study analyzed the main inputs and outputs of China's health reform in order to identify the main problems and highlight the major challenges. It is hoped that this study will provide some reference for health reform in China and other developing countries. STUDY DESIGN: This study focused on health, with human resources and healthcare costs as the main input indicators, and 2-week prevalence of illness and prevalence of non-communicable diseases as the main output indicators. By longitudinal comparison of real data from 2009 to 2014, the effects of China's health reform were analyzed to identify the main challenges, enabling suggestions to be made for future reference. METHODS: This was a retrospective analysis of empirical data. Data were collected between 2009 and 2014 as follows: (1) data on the distribution of healthcare professionals were collected from the Statistical Bulletin of China's Health Development, issued by the National Health and Family Planning Commission every year between 2009 and 2014; (2) data on government health expenditure were obtained from the Annual National Public Fiscal Expenditure Data, released by the Financial Ministry of the People's Republic of China from 2009 to 2014; (3) data on the prevalence of chronic diseases, 2-week prevalence of illness, residents' medical service demands, and utilization of health services were obtained from the Fourth and Fifth National Health Care Surveys in 2008 and 2013; and (4) data on total healthcare expenditure, medical expenditure and out-of-pocket payments were obtained from the 2015 China Statistical Yearbook. RESULTS: From 2009 to 2014, China's healthcare human resources were distributed primarily in hospitals that focus on providing treatment. By 2014, 62.5% of the health professionals and technical personnel were distributed in hospitals. From 2009, the Chinese Government spent more money on health care than previously, with approximately 67% spent on disease treatment and 14.19% spent on disease prevention. However, the 2-week prevalence of illness increased by 5.2 percentage points, and the prevalence of chronic diseases increased by 9 percentage points. Meanwhile, residents' out-of-pocket payments for health care were as high as 50.61% of the total healthcare expenditure and were particularly high in rural areas. CONCLUSION: China should adjust the direction of its health reform as soon as possible to focus on improving health status rather than treatment of disease. In the future, as China's population ageing trend intensifies, China must take effective measures or the country's non-communicable disease rates will continue to increase. To meet this challenge, China's health reform should take effective measures to control the rising trend of the incidence of non-communicable diseases. First, China should focus on the core goal of its health reform policy, which is disease prevention. Second, China should focus on strengthening public health systems to effectively prevent and control key epidemic diseases. Third, China should increase the number of public health personnel, improve the level of education and training of public health personnel and increase the input of funds into the field of public health as soon as possible.

Cell-structure specific necrosis by optical-trap induced intracellular nuclear oscillation.

A drug-free procedure for killing malignant cells in a cell-type specific manner would represent a significant breakthrough for leukemia treatment. Here, we show that mechanically vibrating a cell in a specific oscillation condition can significantly promote necrosis. Specifically, oscillating the cell by a low-power laser trap at specific frequencies of a few Hz was found to result in increased death rate of 50% or above in different types of myelogenous leukemia cells, while normal leukocytes showed very little response to similar laser manipulations. The alteration of cell membrane permeability and cell volume, detected from ethidium bromide staining and measurement of intracellular sodium ion concentration, together with the observed membrane blebbing within 10min, suggest cell necrosis. Mechanics modelling reveals severe distortion of the cytoskeleton cortex at frequencies in the same range for peaked cell death. The disruption of cell membrane leading to cell death is therefore due to the cortex distortion, and the frequency at which this becomes significant is cell-type specific. Our findings lay down a new concept for treating leukemia based on vibration induced disruption of membrane in targeted malignant cells.

Collinearity analysis of allotetraploid Gossypium tomentosum and Gossypium darwinii.

Gossypium tomentosum and G. darwinii are wild allotetraploid cotton species, characterized by many excellent traits, including fiber fineness, drought tolerance, and Fusarium and Verticillium wilt resistance. Based on the construction of F2 linkage groups of G. hirsutum x G. tomentosum and G. hirsutum x G. darwinii, two genetic linkage maps were compared. As a result, we found a total of seven inverted fragments on chr02, chr05, chr08, chr12, chr14, chr16, and chr25, and three translocated fragments on chr05, chr14, and chr26. In addition, comparison of the inverted and translocated fragments revealed that the orientation of four of seven markers in G. tomentosum were consistent with G. hirsutum or G. raimondii. The orientation of one of seven inverted markers of G. darwinii was consistent with G. hirsutum, and the orientation of one of three translocated markers of G. tomentosum was consistent with G. raimondii. These results indicate that, in comparison to G. darwinii, G. tomentosum has a closer genetic relationship to G. hirsutum. These findings will be important for our understanding on the genome structure of G. tomentosum and G. darwinii, and set the scene for further in-depth genome research such as fine mapping, tagging genes of interest from wild relatives, and evolutionary study.

Mapping QTLs for drought tolerance in an F2:3 population from an inter-specific cross between Gossypium tomentosum and Gossypium hirsutum.

Cotton is one of the most important natural fiber crops in the world. Its growth and yield is greatly limited by drought. A quantitative trait locus (QTL) analysis was therefore conducted to investigate the genetic basis of drought tolerance in cotton (Gossypium spp) using 188 F2:3 lines developed from an inter-specific cross between a wild cotton species, G. tomentosum, and an upland cotton, G. hirsutum (CRI-12). A genetic map was constructed using 1295 simple sequence repeat markers, which amplified 1342 loci, distributed on 26 chromosomes, covering 3328.24 cM. A field experiment was conducted in two consecutive years (2014 and 2015) and 11 morphological and physiological traits were recorded under water-limited (W1)/well-watered (W2) regimes at three growth stages (bud, flowering, and full boll). The traits measured included chlorophyll content, plant height, leaf area, leaf number, leaf fresh weight, leaf dry weight, boll weight, number of bolls per plant, and the number of fruiting branches. Sixty-seven and 35 QTLs were found under the W1 and W2 conditions, respectively. Of these, the majority exhibited partial dominance or over-dominance genetic effects for increasing the trait values. Four consistent QTLs were found under the W1 treatment on chromosomes 5, 8, 9, and 16, whereas no consistent QTL was found in W2. Thirteen QTL clusters were also identified on nine chromosomes (2, 3, 5, 6, 9, 14, 15, 16, and 21). These results will help to elucidate the genetic basis of drought tolerance in cotton.

Rapid increase of carbonate in cortical bones of hens during laying period.

The incorporation of carbonate has been recognized as an evident change in bone mineral (bioapatite) during aging. Laying hens (Gushi layer) at 4 stages of age (8 hens each stage) were studied by Raman spectroscopy and X-ray radiography to investigate the mineralogical changes and bone density, respectively. Cortical bones of the humerus and femur show a rapid increase of carbonate (∼1.9 wt.%) from sexual maturity to the peak of hens' laying period, while the densities of the cortical bones are relatively stable. Before sexual maturity, the density of the cortical bones increases considerably during aging. However, after the peak of the laying period, only femoral density continues elevating. Carbonate contents in the cortical bones reach the maximum at the peak of the laying period. Two pathways (halted growth of density and Ca-release due to the CO3 incorporation) could both contribute to the intense Ca requirement for egg laying. Crystallization, however, has no significant changes during aging and the laying period. This study could shed light on the mechanism of mineral losses due to CO3 incorporation, and also shows the advantages of Raman spectroscopy in tracking mineral loss in poultry bone.

Characterizing the malignancy and drug resistance of cancer cells from their membrane resealing response.

In this report, we showed that two tumor cell characteristics, namely the malignancy and drug-resistance status can be evaluated by their membrane resealing response. Specifically, membrane pores in a number of pairs of cancer and normal cell lines originated from nasopharynx, lung and intestine were introduced by nano-mechanical puncturing. Interestingly, such nanometer-sized holes in tumor cells can reseal ~2-3 times faster than those in the corresponding normal cells. Furthermore, the membrane resealing time in cancer cell lines exhibiting resistance to several leading chemotherapeutic drugs was also found to be substantially shorter than that in their drug-sensitive counterparts, demonstrating the potential of using this quantity as a novel marker for future cancer diagnosis and drug resistance detection. Finally, a simple model was proposed to explain the observed resealing dynamics of cells which suggested that the distinct response exhibited by normal, tumor and drug resistant cells is likely due to the different tension levels in their lipid membranes, a conclusion that is also supported by direct cortical tension measurement.

Mechanical oscillations enhance gene delivery into suspended cells.

Suspended cells are difficult to be transfected by common biochemical methods which require cell attachment to a substrate. Mechanical oscillations of suspended cells at certain frequencies are found to result in significant increase in membrane permeability and potency for delivery of nano-particles and genetic materials into the cells. Nanomaterials including siRNAs are found to penetrate into suspended cells after subjecting to short-time mechanical oscillations, which would otherwise not affect the viability of the cells. Theoretical analysis indicates significant deformation of the actin-filament network in the cytoskeleton cortex during mechanical oscillations at the experimental frequency, which is likely to rupture the soft phospholipid bilayer leading to increased membrane permeability. The results here indicate a new method for enhancing cell transfection.