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Background It is well known that circadian rhythms and sleep homeostasis contribute to a pronounced trough in sleepiness and behavioral performance at night. However, the underlying neuroimaging mechanisms remain unclear. How brain-function connectivity is modulated during sleep deprivation (SD) has been rarely examined. Methods By increasing the number of scanning sessions during SD, the current study used voxel-mirrored homotopic connectivity (VMHC) to investigate dynamic changes in interhemispheric communication during one night of SD. Every 2 hours from 10 pm to 06 am (session 1, 10 pm; session 2, 12 am; session 3, 2 am; session 4, 4 am; session 5, 6 am), functional magnetic resonance-imaging data and Stanford Sleepiness Scale (SSS) scores were collected from 36 healthy participants with intermediate chronotype. Dynamic changes in SSS scores and VMHC were determined using one-way repeated-measure ANOVA with the false discovery-rate method to correct for multiple comparisons. Results Significant time effects for VMHC were found mainly in the bilateral thalamus, bilateral superior temporal gyrus, and bilateral precentral gyrus. SSS scores and VMHC in these areas were both found to be monotonously increased during SD. Furthermore, significant positive associations were found between SSS valu and VMHC values in the left superior temporal and right superior gyri. Conclusion These findings might represent the dynamic modulation of circadian rhythm merely or the interaction effects of both circadian rhythm and sleep homeostasis on interhemispheric connectivity within the thalamus, default-mode network, and sensorimotor network. Our study provides more comprehensive information on how SD regulates brain connectivity between hemispheres and adds new evidence of neuroimaging correlates of increased sleepiness after SD.

Endoscopic resection approaches, including endoscopic submucosal dissection (ESD), submucosal tunneling endoscopic resection (STER) and endoscopic full-thickness resection (EFTR), have been widely used for the treatment of submucosal tumors (SMTs) located in the upper gastrointestinal tract. However, compared to SMTs located in the esophagus or stomach, endoscopic resection of SMTs from the esophagogastric junction (EGJ) is much more difficult because of the sharp angle and narrow lumen of the EGJ. SMTs originating from the muscularis propria (MP) in the EGJ, especially those that grow extraluminally and adhere closely to the serosa, make endoscopic resection even more difficult.To investigate the predictors of difficult endoscopic resection for SMTs from the MP layer at the EGJ.A total of 90 patients with SMTs from the MP layer at the EGJ were included in the present study. The difficulty of endoscopic resection was defined as a long procedure time, failure of en bloc resection and intraoperative bleeding. Clinicopathological, endoscopic and follow-up data were collected and analyzed. Statistical analysis of independent risks for piecemeal resection, long operative time, and intraoperative bleeding were assessed using univariate and multivariate analyses.According to the location and growth pattern of the tumor, 44 patients underwent STER, 14 patients underwent EFTR, and the remaining 32 patients received a standard ESD procedure. The tumor size was 20.0 mm (range 5.0-100.0 mm). Fourty-seven out of 90 lesions (52.2%) were regularly shaped. The overall en bloc resection rate was 84.4%. The operation time was 43 min (range 16-126 min). The intraoperative bleeding rate was 18.9%. There were no adverse events that required therapeutic intervention during or after the procedures. The surgical approach had no significant correlation with en bloc resection, long operative time or intraoperative bleeding. Large tumor size (≥ 30 mm) and irregular tumor shape were independent predictors for piecemeal resection (OR: 7.346,Endoscopic resection is an effective treatment for SMTs in the MP layer at the EGJ. Tumors with large size and irregular shape were independent predictors for difficult endoscopic resection.

Objective To investigate nutritional treatment in the intensive care unit (ICU) of the mainland China. Methods A cross-sectional study was conducted in 116 ICUs of 118 mainland hospitals on April 26th, 2017. All patients of these ICUs were investigated at 0 o'clock on April 26th. Demographic and clinical parameters of those patients on April 25th (the investigation day) were recorded, including the dates of hospitalization, ICU admission and nutrition initiation and clinical outcome on 28 days after the investigation day. Results A total of 1953 patients were collected, including 631 females and 1306 males. The mean age was (64.1±19.3) years old (1950 cases). The means of Glasgow Coma Scale (GCS), Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation Ⅱ (APACHEⅡ) scores were (10.76±4.35)(1749 cases), (5.65±3.52)(1783 cases), (17.14±7.31)(1792 cases), respectively. The outcomes of 28 days after the investigation day were 1483 survivors (75.9%), 312 non-survivors (16.0%) and 158 cases (8.1%) being lost to follow-up. There were no significant differences between the males and the females in age, severity of disease and clinical outcomes of 28 days but in height and weight. There were 73.7%(1440 cases) of patients with normal or mildly injured gastrointestinal function, 10.8%(210 cases) with moderately or severely injured function, 1.7%(33 cases) with gastrointestinal failure and 13.2%(258 cases) without evaluation. To the investigation day, enteral nutrition (EN) had been initiated in 69.4%(1356 cases) of patients and parenteral nutrition (PN) in 36.4%(711 cases) of patients. There were 1720(88.1%) patients with EN administration on the investigation day. The proportion of patients with nausea, vomit/regurgitation, aspiration, abdominal pain, abdominal distention and diarrhea was 4.8%(93 cases), 5.4%(105 cases), 0.9%(17 cases), 8.7%(170 cases), 27.5%(538 cases) and 4.3%(84 cases) respectively, while that of patients using EN was 3.1%(40 cases), 4.25%(54 cases), 0.79%(10 cases), 4.41%(56 cases), 26.85%(341 cases) and 5.43%(69 cases) correspondingly. The proportion of cases starting EN within 24, 48 and 72 hours after ICU entry was 22.4%(437/1953), 38.6%(754/1953) and 46.6%(911/1953), respectively. The proportion of cases receiving ≥80% estimated energy target (=past body weight ×25 kcal/kg.d) within 3, 7 and 14 days after ICU entry was 12.9%(78/607), 18.7%(189/1010) and 23%(305/1325) respectively, while that of cases with EN was 9.9%(60/607), 15.0%(151/1010) and 18.6%(246/1325) correspondingly. Conclusions Nowadays, most of patients in the mainland ICUs receive nutrition therapy and the EN usage rate is much higher than the PN rate. However, the time of EN initiation and the target-reaching rate of energy are suboptimal and an individualized plan of nutrition therapy is still missing. Details of energy delivery still need to be improved. DOI: 10.11855/j.issn.0577-7402.2019.05.05

OBJECTIVES: Our previous study has found that n-3 polyunsaturated fatty acids (PUFAs) inhibited inflammation in rats with esophagitis. This study was aimed to observe the protective effect of n-3 PUFAs on esophageal epithelial cells against acid damage and to explore its mechanism. METHODS: Human esophageal epithelial cells (Het-1A) were repeatedly treated with acidified medium (pH 5.0) and PUFAs with different ratios of n-6/n-3 (9:1, 3:1, 1:1 and 1:3, respectively), and Nrf2 agonists or inhibitors were used to assess the role of Nrf2 in mechanism of n-3 PUFAs. Western Blot and Quantitative Real-time PCR (qPCR) were used to assess the expression of Nrf2, NLRP3 and caspase-1. IL-1β, IL-18 and LDH levels in cell culture supernatants were detected by enzyme linked immunosorbent assay (ELISA), while pyroptosis was assessed by caspase-1 and TUNEL double staining. RESULTS: Compared with the normal group, the level of MDA was increased after acid intervention, while that of SOD was decreased (P 0.05). CONCLUSIONS: N-3 PUFAs protected esophageal epithelial cells from acid damage through upregulating Nrf2, which therefore disrupted oxidative stress and NLRP3 inflammasome activation, and then resulted in pyroptosis inhibition. FUNDING SOURCES: This study was supported by the Science Foundation of the Fujian Province, China(Grant No. 2019J01447).

Schizophrenia (SCZ) is an inherited disease, with the familial risk being among the most important factors when evaluating an individual’s risk for SCZ. However, robust imaging biomarkers for the disease that can be used for diagnosis and determination of the prognosis are lacking. Here, we explore the potential of functional connectivity (FC) for use as a biomarker for the early detection of high-risk first-degree relatives (FDRs). Thirty-eight first-episode SCZ patients, 38 healthy controls (HCs), and 33 FDRs were scanned using resting-state functional magnetic resonance imaging. The subjects’ brains were parcellated into 200 regions using the Craddock atlas, and the FC between each pair of regions was used as a classification feature. Multivariate pattern analysis using leave-one-out cross-validation achieved a correct classification rate of 88.15% [sensitivity 84.06%, specificity 92.18%, and area under the receiver operating characteristic curve (AUC) 0.93] for differentiating SCZ patients from HCs. FC located within the default mode, frontal-parietal, auditory, and sensorimotor networks contributed mostly to the accurate classification. The FC patterns of each FDR were input into each classification model as test data to obtain a corresponding prediction label (a total of 76 individual classification scores), and the averaged individual classification score was then used as a robust measure to characterize whether each FDR showed an SCZ-type or HC-type FC pattern. A significant negative correlation was found between the average classification scores of the FDRs and their semantic fluency scores. These findings suggest that FC combined with a machine learning algorithm could help to predict whether FDRs are likely to show an SCZ-specific or HC-specific FC pattern.

Zhu Y, Ren F, Zhu Y, et al. Nat Sci Sleep. 2020;12:1067–1074. The authors have advised that the name of last author on page1067 is incorrect. Mingwen Zheng should be Minwen Zheng. The authors apologize for this error. Read the original article

The smart grid frequently collects consumers’ fine-grained power usage data through smart meters to facilitate various applications, such as billing, load monitoring, regional statistics, and demand response. However, the smart meter reading streams may also pose severe privacy threats to the consumers by leaking their appliances’ ON/OFF status. In this paper, we first quantitatively measure the information leakage with respect to specific appliances’ status from any reading stream, and define a novel privacy notion to bound such information leakage. In addition, we propose a privacy preserving streaming algorithm with different options to effectively convert readings and promptly stream safe readings in different fashions. The output time series readings satisfy our privacy notion while guaranteeing excellent utility, such as extremely low aggregation errors and billing errors. Finally, we experimentally validate the effectiveness and efficiency of our approach using real data sets.

Nutrition therapy is considered an important treatment of burn patients. The aim of the study was to delineate the nutritional support in severe burn patients and to investigate association between nutritional practice and clinical outcomes. Severe burn patients were enrolled (n 100). In 90 % of the cases, the burn injury covered above 70 % of the total body surface area. Mean interval from injury to nutrition start was 2·4 (sd 1·1) d. Sixty-seven patients were initiated with enteral nutrition (EN) with a median time of 1 d from injury to first feed. Twenty-two patients began with parenteral nutrition (PN). During the study, thirty-two patients developed EN intolerance. Patients received an average of about 70 % of prescribed energy and protein. Patients with EN providing

In recent years, with the use of mobile phone APPs, more and more people like to use tourism APPs when traveling, and the tourism industry also enters a new era of wireless tourism. College students are a huge tourist group. This paper will summarize an APP suitable for students’ tourism through the analysis of tourism APPs and tourist groups. This APP will make travel plans based on the student’s time, including travel time, travel residence, travel strategy, travel expenses, tour groups, etc. It also includes working with schools and local police to keep students safe. There should be such an APP for student travel to make it convenient for students to travel, enrich their university experience, and make student travel safer and more convenient.

With the development of the times and the promotion of technology, people’s living standards and aesthetic requirements have also been continuously improved. Intelligent design enables jewelry to break through its position in the traditional sense It is no longer limited to the handmade production of precious metals. Intelligent design can also be applied to jewelry design. The unlimited choice of materials allows designers to have greater design space and imagination. With the development of fashion trends, jewelry as a kind of decoration, in another way shows the personal quality of life and life attitude. Therefore, the more diversified forms of jewelry design are eclectic, and the pursuit of higher levels and more comprehensive forms to create fashionable and personalized products.

Abnormal expression of Retinoid X Receptor α (RXRα) seems to be a frequent incident in a variety of cancers. However, the expression pattern and the mechanisms in gastric carcinoma (GC) remain unclear.In GC tissues and cell lines, the expression levels of RXRα mRNA and protein were detected by Q-PCR and Western blot, respectively; the localization of RXRα was evaluated by immunohistochemistry (IHC) or immunocytochemistry (ICC). The effect of IL-1β on RXRα expression and localization was detected by Western blot and ICC. Nuclear factor-κB (NF-κB) pathway was assessed via Western blot.RXRα expression was markedly elevated at both mRNA and protein levels in GC tissues and cell lines (all P0.05). The abnormal overexpression of RXRα was predominantly visualized in cytoplasm. IL-1β significantly induced cytoplasmic expression of RXRα in a time-dependent manner. Co-incubation with IL-1β enhanced phospho-IKKα (p-IKKα) expression and this effect could be inhibited by the specific inhibitor for NF-κB (all P0.01).IL-1β upregulated RXRα through activation of NF-κB signaling and these suggested a possible clinic significance of retinoid receptor expression in the diagnosis and treatment of GC.

BACKGROUND: The aim of the study was to identify the clinical features and the factors associated with burn induced mortality among young adults after exposure to indoor explosion and fire. METHODS: This is an observational study which included burn patients who were admitted to eighteen ICUs after a fire disaster. Epidemiologic and clinical characteristics, as well as therapy were recorded. The primary outcome was 90-day mortality. The mortality-related factors were also analyzed. RESULTS: There were 167 burn patients enrolled in the study, the median age was 38 years, 62 (37.1%) patients died within 90 days. Seventy-one percent of patients had a burn size ≥90% TBSA, and 73.7% of patients had a full-thickness burn area above 50% TBSA. The survivors had lower Baux scores, and received earlier escharectomy and autologous skin grafts. The 50% mortality rates (LA50s) for burn size and full-thickness burn area were 95.8% and 88.6% TBSA, respectively. The multivariate analysis showed that full-thickness burn area over 50% TBSA and residual burned surface area (RBSA)/TBSA at 28 days were strong predictors of mortality among burn patients (odds ratio 2.55; 95% CI, 1.01 to 6.44, P=0.047; odds ratio 1.07; 95% CI, 1.04 to 1.09, P

Objective To explore predictors of the 6-month clinical outcome of thalamic hemorrhage, and evaluate if minimally invasive thalamic hematoma drainage (THD) could improve its prognosis. Methods A total of 54 patients with spontaneous thalamic hemorrhage were evaluated retrospectively. Clinical data, including demographics, stroke risk factors, neuroimaging variables, Glasgow Coma Score (GCS) on admission, surgical strategy, and outcome, were collected. Clinical outcome was assessed using a modified Rankin Scale, six months after onset. Univariate analysis and multivariate logistic regression analysis were performed to determine predictors of a poor outcome. Results Conservative treatment was performed for five patients (9.3%), external ventricular drainage (EVD) for 20 patients (37.0%), THD for four patients (7.4%), and EVD combined with THD for 25 patients (46.3%). At six months after onset, 21 (38.9%) patients achieved a favorable outcome, while 33 (61.1%) had a poor outcome. In the univariate analysis, predictors of poor 6-month outcome were lower GCS on admission (P = 0.001), larger hematoma volume (P < 0.001), midline shift (P = 0.035), acute hydrocephalus (P = 0.039), and no THD (P = 0.037). The independent predictors of poor outcome, according to the multivariate logistic regression analysis, were no THD and larger hematoma volume. Conclusions Minimally invasive THD, which removes most of the hematoma within a few days, with limited damage to perihematomal brain tissue, improved the 6-month outcome of thalamic hemorrhage. Thus, THD can be widely applied to treat patients with thalamic hemorrhage.

// Hong-Yue Ren 1, * , Fan Liu 2, * , Gui-Li Huang 3 , Yu Liu 4 , Jin-Xing Shen 4 , Pan Zhou 3 , Wen-Ming Liu 5 , Dong-Yan Shen 4 1 Department of Pathology, The Affiliated Southeast Hospital of Xiamen University, Zhangzhou 363000, Fujian Province, China 2 Department of Medical College, Xiamen University, Xiamen 361005, Fujian Province, China 3 State Key Laboratory of Cellular Stress Biology, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Department of Life Sciences, Xiamen University, Xiamen 361005, Fujian Province, China 4 Department of Biobank, The First Affiliated Hospital of Xiamen University, Xiamen 361003, Fujian Province, China 5 Department of Gastroenterology, Zhongshan Hospital, Gastroenterology Institute of Xiamen University, Gastroenterology Center of Xiamen, Xiamen 361003, Fujian Province, China * These authors have contributed equally to this work Correspondence to: Dong-Yan Shen, email: shendongyan@163.com Wen-Ming Liu, email: 846928419@qq.com Keywords: RARα, gastric carcinoma, Akt, IL-1β Received: July 02, 2016 Accepted: December 01, 2016 Published: December 27, 2016 ABSTRACT Abnormal expression and function of retinoic acid receptor α (RARα) have been reported to be associated with various cancers including acute promyelocytic leukemia and hepatocellular carcinoma. However, the role and the mechanism of RARα in gastric carcinoma (GC) were unknown. Here, the expression of RARα was frequently elevated in human GC tissues and cell lines, and its overexpression was closely correlated with tumor size, lymph node metastasis and clinical stages in GC patients. Moreover, RARα overexpression was related with pathological differentiation. Functionally, RARα knockdown inhibited the proliferation and metastasis of GC cells, as well as enhanced drug susceptibility both in vitro and in vivo . Additionally, RARα knockdown suppressed GC progression through regulating the expression of cell proliferation, cell cycle, invasion and drug resistance associated proteins, such as PCNA, CyclinB1, CyclinD2, CyclinE, p21, MMP9 and MDR1. Mechanistically, the above oncogenic properties of RARα in GC were closely associated with Akt signaling activation. Moreover, overexpression of RARα was induced by IL-1β/Akt signaling activation, which suggested a positive feedback loop of IL-1β/Akt/RARα/Akt signaling in GC. Taken together, we demonstrated that RARα was frequently elevated in GC and exerted oncogenic properties. It might be a potential molecular target for GC treatment.

The privacy preserving issues have received significant attentions in various domains. Various models and techniques have been proposed to achieve optimal privacy with minimal costs. However, side-channel leakages (such as, publicly-known algorithms of data publishing, observable traffic information in web application, fine-grained readings in smart metering) further complicate the process of privacy preservation. In this thesis, we make the first effort on investigating a general framework to model side-channel attacks across different domains and applying the framework to various categories of applications. In privacy-preserving data publishing with publicly-known algorithms, we first theoretically study a generic strategy independent of data utility measures and syntactic privacy properties. We then propose an efficient approach to preserving diversity. In privacy-preserving traffic padding in Web applications, we first propose a formal PPTP model to quantify the privacies and costs based on the key observation about the similarity between data publishing and traffic padding. We then introduce randomness into the previous solutions to provide background knowledge-resistant privacy guarantee. In privacy-preserving smart metering, we propose a light-weight approach to simultaneously preserving privacy on both billing and consumption aggregation based on the key observation about the privacy issue beyond the fine-grained readings.

Understanding the neural basis of schizophrenia (SZ) is important for shedding light on the neurobiological mechanisms underlying this mental disorder. Structural and functional alterations in the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), hippocampus, and medial prefrontal cortex (MPFC) have been implicated in the neurobiology of SZ. However, the effective connectivity among them in SZ remains unclear. The current study investigated how neuronal pathways involving these regions were affected in first-episode SZ using functional magnetic resonance imaging (fMRI). Forty-nine patients with a first-episode of psychosis and diagnosis of SZ-according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision-were studied. Fifty healthy controls (HCs) were included for comparison. All subjects underwent resting state fMRI. We used spectral dynamic causal modeling (DCM) to estimate directed connections among the bilateral ACC, DLPFC, hippocampus, and MPFC. We characterized the differences using Bayesian parameter averaging (BPA) in addition to classical inference (t-test). In addition to common effective connectivity in these two groups, HCs displayed widespread significant connections predominantly involved in ACC not detected in SZ patients, but SZ showed few connections. Based on BPA results, SZ patients exhibited anterior cingulate cortico-prefrontal-hippocampal hyperconnectivity, as well as ACC-related and hippocampal-dorsolateral prefrontal-medial prefrontal hypoconnectivity. In summary, spectral DCM revealed the pattern of effective connectivity involving ACC in patients with first-episode SZ. This study provides a potential link between SZ and dysfunction of ACC, creating an ideal situation to associate mechanisms behind SZ with aberrant connectivity among these cognition and emotion-related regions.

// San-Gang Wu 1, * , Zhao-Qiang Zhang 2, * , Wen-Ming Liu 3, * , Zhen-Yu He 4 , Feng-Yan Li 4 , Huan-Xin Lin 4 , Jia-Yuan Sun 4 , Hui Lin 5 , Qun Li 4 1 Department of Radiation Oncology, the First Affiliated Hospital of Xiamen University, Xiamen 361003, People’s Republic of China 2 Eye Institute of Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Medical College of Xiamen University, Xiamen 361003, People’s Republic of China 3 Department of Gastroenterology, Zhongshan Hospital of Xiamen University, Xiamen 361003, People’s Republic of China 4 Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Department of Radiation Oncology, Collaborative Innovation Center of Cancer Medicine, Guangzhou 510060, People’s Republic of China 5 Department of Cardiovascular and Thoracic Surgery, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning 530021, People’s Republic of China * These authors contributed equally to this work Correspondence to: Hui Lin, e-mail: linhui33622@sina.com Qun Li, e-mail: liqun0799@126.com Keywords: esophageal cancer, lymph nodes, preoperative radiotherapy, survival, SEER Received: October 29, 2015 Accepted: February 24, 2016 Published: March 16, 2016 ABSTRACT To assess the impact of the number of resected lymph nodes (RLNs) for survival in esophageal cancer (EC) patients treated with preoperative radiotherapy and cancer-directed surgery. The Surveillance Epidemiology and End Results (SEER) database was queried to identify EC patients treated from 1988 to 2012 who had complete data on the number of positive lymph nodes and number of RLNs. Kaplan–Meier survival analysis and Cox regression proportional hazard methods were used to determine factors that significantly impact cause-specific survival (CSS) and overall survival (OS). There were a total of 3,159 patients who received preoperative radiotherapy and cancer-directed surgery. The median number of RLNs was 10 in both patients who received and did not receive preoperative radiotherapy ( P = 0.332). Cox regression univariate and multivariate analysis showed that RLN count was a significant prognostic factor for CSS and OS. Patients with 11–71 RLNs had better CSS (hazard ratio [HR] = 0.694, 95% confidence interval [CI]: 0.603–0.799, P < 0.001) and OS (HR = 0.724, 95% CI: 0.636–0.824, P < 0.001) than patients with 1–10 RLNs. The 5-year CSS rates were 39.1% and 44.8% in patients with 1–10 RLNs and 11–71 RLNs, respectively ( P < 0.001). The 5-year OS rates were 33.7% and 39.9% in patients with 1–10 RLNs and 11–71 RLNs, respectively ( P < 0.001). A higher number of RLNs was associated with better survival by tumor stage and nodal stage (all P < 0.05). RLN count is an independent prognostic factor in EC patients who undergo preoperative radiotherapy and cancer-directed surgery.

Studies comparing gray matter (GM) volume of schizophrenic patients with or without auditory verbal hallucinations (AVHs) to that of normal controls remain controversial. This project aims to investigate changes of GM volumes of drug-naïve schizophrenic patients with and without AVHs. Eighteen first episode schizophrenic (FES) patients with AVHs, 18 FES patients without AVHs and 18 healthy controls were scanned using structural MRI. Voxel-based morphometry (VBM) analysis was conducted to investigate changes of GM volume among the three groups. Patients with and without AVHs exhibited reduced GM volumes relative to normal controls in the left superior temporal gyrus, frontal regions, cerebellum and caudate. Further analysis of the GM of subcortical structures found that patients with AVHs had reduced thalamic volume than healthy controls. No significant difference was found between patients with and without AVHs. Significant correlation was found between the total scores of the Positive and Negative Syndrome Scale and bilateral thalamic volume. ROC analysis of thalamic volumes of the patients with AVHs and normal controls showed that the area under the curve was 0.698 (P = 0.043). The decreased thalamic volumes might serve as a biomarker for discriminating FES AVHs patients from normals.

While web-based applications are becoming increasingly ubiquitous, they also present new security and privacy challenges. In particular, recent research revealed that many high profile Web applications might cause private user information to leak from encrypted traffic due to side-channel attacks exploiting packet sizes and timing. Moreover, existing solutions, such as random padding and packet-size rounding, are shown to incur prohibitive cost while still not ensuring sufficient privacy protection. In this paper, we propose a novel k-indistinguishable traffic padding technique to achieve the optimal tradeoff between privacy protection and communication and computational cost. Specifically, we first present a formal model of the privacy-preserving traffic padding (PPTP). We then formulate PPTP problems under different application scenarios, analyze their complexity, and design efficient heuristic algorithms. Finally, we confirm the effectiveness and efficiency of our algorithms by comparing them to existing solutions through experiments using real-world Web applications.

Using a heuristic search combined with some algebraic techniques, several examples for 10-variable Boolean functions with nonlinearity 488, algebraic degree 7, and resiliency degree 2 , were constructed. This construction affirmatively answers the open problem about the existence of such functions.