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Traditional access control models are hard to restrain the malicious behavior of authorized users. Accord-ingly, Hadoop platform with this access control model is difficult to prevent the risk of privacy disclosure. A model of access control based on risk was proposed. A risk function of information entropy was designed from users’ his-torical behavior based on setting the tags of subject and object. Furthermore, the tracking chain of risk was built, which could adjust the users’ access authority dynamically according to the risk value and its volatility. Combining with access token and risk supervision, the risk access control mechanism for big data privacy protection was real-ized, which could be applied to enhance the security of Hadoop Kerberos protocol. Finally, the experiment result shows that the model can constrain the authorized users’ access behavior effectively.

Study Design: Prospective cohort study.Objective: To assess the differences in the clinical and radiological outcomes between oblique lateral interbody fusion (OLIF) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF).Summary Of Background Data: Nowadays, there is still a controversy regarding whether OLIF is superior to MI-TLIF in the management of degenerative lumbar disease.Methods: Between August 3, 2019 and February 3, 2020, 137 patients were assigned to OLIF or MI-TLIF at their request and the surgeon's discretion: 71 in the OLIF group and 66 in the MI-TLIF group. The perioperative data, patient-reported outcomes, radiographic outcomes, and complications were compared between the two groups.Results: The OLIF group showed shorter operation time (110.5 vs.183.8 minutes, P < 0.001), lesser estimated blood loss (123.1 vs. 232.0 mL, P < 0.001), shorter length of hospital stay (5.5 vs. 6.7 days, P < 0.001), and lower serum creatine kinase (CK) (1 day postoperatively) (376.0 vs. 541.8 IU/L, P < 0.01) than that of MI-TLIF group. Both groups showed no significant differences in the visual analog scale (VAS) scores of lower back and leg pain and the Oswestry Disability Index (ODI) scores preoperatively and at 1, 3, and 12 months postoperatively, respectively (P > 0.05). Compared with the MI-TLIF group, the OLIF group showed better restoration of disc height (DH) (4.7/4.6/4.7 vs. 3.7/3.7/3.7 mm, P < 0.01) and lumbar lordosis angle (LLA) (10.5°/10.8°/11.1° vs. 5.8°/5.7°/5.3°, P < 0.001), but not the value of segmental lordosis angle (SLA) (P > 0.05) at 1 day, 1 month, and 1 year postoperatively, respectively. The complication rate of OLIF was higher than that of MI-TLIF (29.4% vs. 9.7%, P < 0.01).Conclusion: Compared with MI-TLIF, OLIF showed similar results in terms of patient-reported outcomes, restoration of SLA and fusion rate, and superior results with respect to restoration of DH and LLA, operation time, estimated blood loss, length of hospital stay, and serum CK levels (1 day postoperatively). Even though the complication rate of OLIF is higher than that of MI-TLIF, it does not bring persistent and substantial damage to the patients.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

In this study, an ether-bridged aromatic carboxylic acid, 2-(2-carboxyphenoxy)terephthalic acid (H3cpta), was applied as the building block for the generation of two new Co(II)-based coordination polymers (CPs) with the chemical formulae of [Co3(μ5-cpta)2(2,2′-bipy)2]n (1, 2,2′-bipy = 2,2′-bipyridine) [Co3(μ3-cpta)2(phen)3(py)3(H2O)3]n (2, phen =1,10-phenanthroline, py = pyridine) by reaction of the Co(NO3)2·6H2O with the H3cpta ligand in the presence of different N-donor co-ligands under the hydrothermal reaction conditions. The single-crystal X-ray diffraction study shows that compound 1 features a 2D layered structure which has been reported previously and compound 2 shows a ladder-like 1D network. Furthermore, the treatment effect of compounds 1 and 2 on the rats undergoing gastrointestinal surgery was evaluated. The hemodynamics of the rats was measured after compound 1 or 2 treatment. Besides, the Richmond Agitation–Sedation Scale was also performed for the evaluation of rats' cognitive function after the treatment. [ABSTRACT FROM AUTHOR]

Oblique lateral lumbar interbody fusion (OLIF) has been extensively used, with satisfactory outcomes for the treatment of degenerative lumbar disease. This article aims to demonstrate a modified lateral approach, also known as the anteroinferior psoas (AIP) technique for OLIF, which is expected to enhance security by operating under direct vision. The core procedures of our technique are as follows. First, a minimal skin incision is recommended 2 cm backward compared with the normal incision of OLIF, facilitating the oblique placement of the working channel and the orthogonal maneuver for the cage placement. Second, two special custom‐made retractors, as an alternative to the index finger, are used to pull the psoas muscle to the dorsal side and pull the abdominal organs together with extraperitoneal fate to the ventral side under direct visualization, making the exposure of the working channel convenient and safe and avoiding radiation exposure. Third, the anterior border of the psoas is bluntly dissected and retracted backwards, obviously enlarging the retroperitoneal anatomic corridor and then expanding clinical indications of OLIF. The benefits of this technique include that it has a short learning curve, satisfactory clinical outcomes, and low risk of perioperative complications. [ABSTRACT FROM AUTHOR]

Both CO and H2 can be utilized as energy sources during the autotrophic growth of Clostridium ljungdahlii. In principle, CO is a more energetically and thermodynamically favorable energy source for gas fermentation in comparison to H2. Therefore, metabolism may vary during growth under different energy sources. In this study, C. ljungdahlii was fed with CO and/or CO2/H2 at pH 6.0 with a gas pressure of 0.1 MPa. C. ljungdahlii primarily produced acetate in the presence of H2 as an energy source, but produced alcohols with CO as an energy source under the same fermentation conditions. A key enzyme activity assay, metabolic flux analysis, and comparative transcriptomics were performed for investigating the response mechanism of C. ljungdahlii under different energy sources. A CO dehydrogenase and an aldehyde:ferredoxin oxidoreductase were found to play important roles in CO utilization and alcohol production. Based on these findings, novel metabolic schemes are proposed for C. ljungdahlii growing on CO and/or CO2/H2. These schemes indicate that more ATP is produced during CO-fermentation than during H2-fermentation, leading to increased alcohol production. [ABSTRACT FROM AUTHOR]

Objective: To compare postoperative imaging results, clinical outcomes and complications between the multifidus muscle bundle (MMB) approach and the conventional open (CO) approach in one‐level posterior lumbar interbody fusion (PLIF). Methods: Based on the inclusion and exclusion criteria, 201 of 351 patients in our hospital were enrolled in this prospective study and underwent MMB‐PLIF or CO‐PLIF randomly: 111 patients in the MMB‐PLIF group and 90 patients in the CO‐PLIF group. A total of 100 patients failed to be followed up in the following 7–9 years. Therefore, in this study, 52 patients of the MMB group and 49 patients of the CO group were included. We evaluated the differences in terms of multifidus atrophy rate, intervertebral disc height and segmental lordosis restoration of the operation segment, lumbar lordosis restoration, fusion rate, visual analogue scale (VAS) for back and leg pain, Oswestry disability index (ODI), complication rates, and patient satisfaction rates between the two groups. Correlation between multifidus muscle degeneration and the incidence of complications was investigated, and we compared the multifidus muscle degeneration rate between patients with or without intractable back pain or adjacent segment degeneration. Results: There were no significant differences in age, sex, body mass index (BMI), diagnosis, segments distribution, and mean follow‐up time between the MMB‐PLIF group and the CO‐PLIF group. In addition, no differences regarding sex, age, or BMI were found between the lost follow‐up group and the successful follow‐up group. In regard to imaging and clinical evaluation, at the final follow‐up, there were significant differences in multifidus atrophy rates (27.0% ± 6.8% vs 38.7% ± 10.9%), lumbar lordosis restoration (4.6° ± 2.5° vs 3.0° ± 1.9°), postoperative VAS for back pain (1.1 ± 0.9 vs 1.8 ± 1.2), ODI (7.7 ± 5.0 vs 12.4 ± 6.7), and patient satisfaction rates (86.5% vs 61.2%) between MMB‐PLIF and CO‐PLIF groups. However, there were no significant differences in segmental lordosis, intervertebral height restoration, postoperative VAS for leg pain or fusion rate between the two groups. In regards to complications, there were significant differences in the incidence of adjacent segment degeneration (3.8% vs 14.3%), intractable back pain (3.8% vs 22.4%), and residual neurological symptoms (5.8% vs 20.4%) between the two groups (P < 0.05) at the final follow‐up. In addition, patients with adjacent segment degeneration and intractable back pain were observed with more significant multifidus muscle atrophy than those without these two complications (31.9% ± 1.1% vs 39.6% ± 2.1% and 30.9% ± 1.1% vs 42.8% ± 2.1%). Conclusion: Compared with CO‐PLIF, MMB‐PLIF had advantages in relation to protection of the multifidus muscle, better maintenance of lumbar lordosis, reduced lower back pain and ODI score, fewer complications, and a higher patient satisfaction rate. Protection of the multifidus muscle in lumbar surgery is an important aspect of minimally invasive surgery. [ABSTRACT FROM AUTHOR]

With the development and prevalence of online social networks, there is an obvious tendency that people are willing to attend and share group activities with friends or acquaintances. This motivates the study on group recommendation, which aims to meet the needs of a group of users, instead of only individual users. However, how to aggregate different preferences of different group members is still a challenging problem: 1) the choice of a member in a group is influenced by various factors, e.g., personal preference, group topic, and social relationship; 2) users have different influences when in different groups. In this paper, we propose a generative geo-social group recommendation model (GSGR) to recommend points of interest (POIs) for groups. Specifically, GSGR well models the personal preference impacted by geographical information, group topics, and social influence for recommendation. Moreover, when making recommendations, GSGR aggregates the preferences of group members with different weights to estimate the preference score of a group to a POI. Experimental results on two datasets show that GSGR is effective in group recommendation and outperforms the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Aim Retinal anatomical studies have used the Drasdo & Fowler three-refracting surface schematic eye to convert between retinal distances and object field angles. We compared its performance at this task with those of more sophisticated four-refracting surface schematic eyes. Method Raytracing was performed for Drasdo & Fowler, Lotmar, Navarro, Liou & Brennan, Kooijman and Atchison schematic eyes, and some of their variants. Results The Drasdo & Fowler eye gives a greater rate of change of object field angle with retinal distance at the retinal centre of about 5% than the other schematic eyes. This rate of change also increases much more quickly into the peripheral retina for the Drasdo & Fowler eye than for the other eyes. The reason for these differences is only that the Drasdo & Fowler eye is shorter than the other eyes. The relationship between retinal distance and visual field angle appears robust to changes in retinal radius of curvature when the retina is spherical. The retinal asphericity of Kooijman and Atchison eyes appears to play a role beyond 14 mm (~50°). Conclusion Changing the length of the Drasdo & Fowler eye, to match those of the four-refracting surface schematic eyes, gives similar relationships between retinal distance and object field angle up to a retinal distance of approximately 14 mm (~50°). The relationship will change with refractive error as this is related to axial length and to retinal shape, and this should be taken into consideration for accurate conversions. For distances and angles beyond 14 mm and ~50°, retinal shape should be taken into account. [ABSTRACT FROM AUTHOR]

Abstract: Long-term high-resolution climate proxies are essential for understanding climate variability on the Tibetan Plateau (TP), where few long-term climate records are available. In this paper, we describe a summer (August) temperature reconstruction over the period 1385–2002 based on a tree-ring width chronology of Balfour spruce (Picea likiangensis var. balfouriana) on the southeastern TP created using the Regional Curve Standardization method. The reconstruction explains 44.7% of the variance in the instrumental temperature records during the calibration period (1962–2002), and captures temperature variability over a broad region of the TP. Warmer than average Augusts were found during the periods 1446–1494, 1509–1522, 1553–1567, 1797–1812, 1845–1905 and 1918–2002. Cooler than average Augusts occurred from 1385–1416, 1426–1445, 1495–1508, 1523–1552, 1568–1686, 1695–1718, 1725–1796, 1813–1844 and 1906–1917. A warming trend in the 20th century was unprecedented during the past six centuries. The reconstruction closely matched other tree-ring summer temperature reconstructions from neighboring regions, as well as patterns from ice-core δ18O data, and fluctuated in synchrony with Northern Hemisphere temperature reconstructions. [Copyright &y& Elsevier]

To study the historical temperature variation in Yili of Xinjiang, the tree-ring chronologies of maximum density (MXD) and tree-ring width (TRW) were established with the Schrenk Spruce (Picea schrenkiana Fisch. et Mey) collected from six sites to analyze the characteristics and ability of response to climate change. The results suggest that the MXD chronology of the Schrenk Spruce from different sampling sites responded to climate change well and were positively correlated with the mean maximum temperature and the mean temperature from April to Aàgust in the study area. The mean maximum temperature anomaly from April to August, spanning the years from 1848 to 2000, was reconstructed by three MXD chronologies which were selected by stepwise regression. The reconstructed function was stable and explained 56.2% of the variance. The reconstructed results indicated a cold span of 153 years in spring and summer from the beginning of the 1950s to the beginning of the 1970s in the Yili valley. No strongly increasing tendency was detected in the mean maximum temperature anomaly from April to August during this reconstructed period. [ABSTRACT FROM AUTHOR]

Based on the investigation data of Sabina przewalskii tree-ring width at six sites at upper timberlines in eastern mountainous region of Qaidam Basin, the standard tree-ring chronologies of S. przewalskii were established. Cluster analysis indicated that there existed geographical differences in the radial growth of S. przewalskii among the sites. Higher similarity was observed between two northern sites, and among four central and southern sites. Climatic factors had different effects on the radial growth of S. przewalskii of the two clusters. The radial growth of S. przewalskii was positively correlated with the precipitation in current year's June at northern sites, and with the air temperature in previous year's November and current year's July at central and southern sites. [ABSTRACT FROM AUTHOR]

The uncertain future was dealt with the Scenario Method, the new concept of minimum investment and the compensatory investment of the power planning was introduced. Then the function of the minimum investment and the compensatory investment was found. The optimal flexible planning can be obtained by means of the Equal Incremental principle. The test examples show that this method is more suitable and flexible than the traditional method. Its total investment is less than traditional strategies. [ABSTRACT FROM AUTHOR]

The unascertained number (UN) was used to deal with the uncertainty of electric power networks planning. A novel method of electric power networks flexible planning was presented based on the blind model (BM) of UN. Then the optimal flexible planning can. be obtained by using the analysis of cost-benefit. This method was proved in some test examples. The analysis shows that the blind model and its strategy is flexible and effective. [ABSTRACT FROM AUTHOR]

By employing molecular mechanics and molecular dynamics simulations, we investigate the radial collapses and elasticities of different chiral single-walled carbon nanotubes (SWCNTs) with divacancy, and 5-8-5 defects. It is found that divacancy and 5-8-5 defect can reduce the collapse pressure (Pc) of SWCNT (10, 10) while 5-8-5 defect can greatly increase Pc of SWCNT (17, 0). For example, 5-8-5 defect can make Pc of SWCNT (17, 0) increase by 500%. A model is established to understand the effects of chirality, divacancy, and 5-8-5 defect on radial collapse of SWCNTs. The results are particularly of value for understanding the mechanical behavior of SWCNT with divacancy, and the 5-8-5 defect that may be considered as a filler of high loading composites. [ABSTRACT FROM AUTHOR]

Purpose: To assess the efficacy of diffusion kurtosis imaging (DKI) in the prediction of the treatment response to neoadjuvant chemotherapy in patients with locally advanced gastric cancer (LAGC).Methods: A total of 31 LAGC patients were enrolled in this prospective study. All patients underwent diffusion-weighted MRI examination (with b = 01, 2001, 5001, 8002, 10004, 15004, 20006 s/mm2, the subscript denotes the number of signal averages) before and after chemotherapy. DKI and mono-exponential (b = 0, 800 s/mm2) models were built. Apparent diffusion coefficient (ADC), mean diffusivity (MD) and mean kurtosis (MK) of the LAGC tumors were measured. The absolute change values (ΔX) and percentage change values (%ΔX) of the above parameters post neoadjuvant chemotherapy (NACT) were calculated. The response was evaluated according to the pathological tumor regression grade scores (effective response group: TRG 0-2, poor response group: TRG 3). Mann-Whitney U test and receiver operating characteristic (ROC) curves were applicated for statistical analysis.Results: There were 17 patients in the effective response group (ERG), and 14 patients in the poor response group (PRG). The MKpre and MKpost values in PRG were significantly higher than those in ERG [(0.671 ± 0.026) and (0.641 ± 0.019) vs. (0.584 ± 0.023) and (0.519 ± 0.018), p < 0.001]. ADCpost and MDpost in PRG were significantly lower than those in ERG (p = 0.005, p =0.001). Significant differences were also observed for % ΔMK, ΔMD and ΔMK between the two groups (p < 0.05). The area under the curve (AUC) for the prediction of PRG was highest for MKpost (AUC = 0.958, cutoff value = 0.614). The MKpre and MKpost had the highest sensitivity (91.70 %) and specificity (93.80 %) in the prediction of PRG, respectively.Conclusion: Both DKI and ADC values show potential for the prediction of the PRG in LAGC patients. The DKI parameters, especially MKpost displayed the best performance. [ABSTRACT FROM AUTHOR]