Category: Nevin Manimala

PLoS One. 2021 Apr 9;16(4):e0249359. doi: 10.1371/journal.pone.0249359. eCollection 2021.

ABSTRACT

A novel penalty for the proportional hazards model under the interval-censored failure time data structure is discussed, with which the subject of variable selection is rarely studied. The penalty comes from an idea to approximate some information criterion, e.g., the BIC or AIC, and the core process is to smooth the ℓ0 norm. Compared with usual regularization methods, the proposed approach is free of heavily time-consuming hyperparameter tuning. The efficiency is further improved by fitting the model and selecting variables in one step. To achieve this, sieve likelihood is introduced, which simultaneously estimates the coefficients and baseline cumulative hazards function. Furthermore, it is shown that the three desired properties for penalties, i.e., continuity, sparsity, and unbiasedness, are all guaranteed. Numerical results show that the proposed sparse estimation method is of great accuracy and efficiency. Finally, the method is used on data of Nigerian children and the key factors that have effects on child mortality are found.

PMID:33836005 | DOI:10.1371/journal.pone.0249359

IEEE J Biomed Health Inform. 2021 Apr 9;PP. doi: 10.1109/JBHI.2021.3072246. Online ahead of print.

ABSTRACT

Cataract causes more than half of all blindness worldwide. The most effective treatment is surgery, where cataract is often replaced by intraocular lens (IOL). Beyond saving vision, toric IOL implantation is becoming increasingly popular to correct corneal astigmatism. It is important to precisely position and align the axis of IOL during surgery to achieve optimal post-operative astigmatism correction. Comparing with conventional manual marking, automated markerless IOL alignment can be faster, more accurate and non-invasive. Here we propose a framework for computer-assisted intraoperative IOL positioning and alignment based on detection and tracking. Firstly, the iris boundary was segmented and the eye center was determined. A statistical sampling method was developed to segment iris and generate training labels, and both conventional algorithms and deep convolutional neural network (CNN) methods were evaluated. Then, regions of interests (ROIs) containing high density of scleral capillaries were used for tracking eye rotations. Both correlation filter and CNN methods were evaluated for tracking. Cumulative errors during long-term tracking were corrected using a reference image. Validation studies against manual labeling using 7 clinical cataract surgical videos demonstrated that the proposed algorithm achieved an average position error around 0.2 mm, an axis alignment error of < 1 degree, and a frame rate of > 25 FPS, and can be potentially used intraoperatively for markerless IOL positioning and alignment during cataract surgery.

PMID:33835929 | DOI:10.1109/JBHI.2021.3072246

JMIR Public Health Surveill. 2021 Apr 2. doi: 10.2196/24623. Online ahead of print.

ABSTRACT

BACKGROUND: Social media has become a ubiquitous part of daily life during the COVID-19 isolation. However, the role of social media use in depression and suicidal ideation of the general public remains unclear. Related empirical studies were limited and reported inconsistent findings. Little is known about the potential underlying mechanisms that may illustrate the relationship between social media use and depression/suicidal ideation during COVID-19.

OBJECTIVE: This study tested the mediation effects of social loneliness and post-traumatic stress (PTSD symptoms) on the relationship between social media use and depressive symptoms/suicidal ideation and the moderation effect of age on the mediation models.

METHODS: We administered a population-based random telephone survey in May and June 2020 when infection control measures were being vigorously implemented in Hong Kong. 1070 adults (658 social media users and 412 non-users) completed the survey. Structural equation modeling (SEM) and multigroup SEM were conducted to test the mediation and moderation effects.

RESULTS: The weighted prevalence of probable depression was 11.6%; 1.6% had suicidal ideation in the past two weeks. Both moderated mediation models of depressive symptoms (χ2(df)=335.34(62), p<.05, CFI=.94, NNFI=.92, RMSEA=.06) and suicidal ideation (χ2(df)=50.80(34), p<.05, CFI=.99, NNFI=.99, RMSEA=.02) showed acceptable model fit. There was a significantly negative direct effect of social media use on depressive symptoms among older people (β=-.07, p=.04) but not among younger people (β=.04, p=.55). The indirect effect via PTSD symptoms was significantly positive among both younger (β=.09, p=.02) and older people (β=.10, p=.01). The indirect effect via social loneliness was significant among older people (β=-.01, p=.04) but not among younger people (β=.01, p=.31). The direct effect of social media use on suicidal ideation was not statistically significant in both age groups (p>.05). The indirect effects via PTSD symptoms were statistically significant among younger (β=.02, p=.04) and older people (β=.03, p=.01). Social loneliness was not a significant mediator between social media use and suicidal ideation among neither younger nor older people (p>.05).

CONCLUSIONS: Social media may be a ‘double-edged sword’ for psycho-social well-being during COVID-19 and its roles vary across age groups. The mediators identified in this study can be addressed by psychological interventions to prevent severe mental health problems during and after COVID-19.

PMID:33835937 | DOI:10.2196/24623

IEEE Trans Neural Netw Learn Syst. 2021 Apr 9;PP. doi: 10.1109/TNNLS.2021.3062062. Online ahead of print.

ABSTRACT

In concept drift adaptation, we aim to design a blind or an informed strategy to update our best predictor for future data at each time point. However, existing informed drift adaptation methods need to wait for an entire batch of data to detect drift and then update the predictor (if drift is detected), which causes adaptation delay. To overcome the adaptation delay, we propose a sequentially updated statistic, called drift-gradient to quantify the increase of distributional discrepancy when every new instance arrives. Based on drift-gradient, a segment-based drift adaptation (SEGA) method is developed to online update our best predictor. Drift-gradient is defined on a segment in the training set. It can precisely quantify the increase of distributional discrepancy between the old segment and the newest segment when only one new instance is available at each time point. A lower value of drift-gradient on the old segment represents that the distribution of the new instance is closer to the distribution of the old segment. Based on the drift-gradient, SEGA retrains our best predictors with the segments that have the minimum drift-gradient when every new instance arrives. SEGA has been validated by extensive experiments on both synthetic and real-world, classification and regression data streams. The experimental results show that SEGA outperforms competitive blind and informed drift adaptation methods.

PMID:33835922 | DOI:10.1109/TNNLS.2021.3062062

AIDS Patient Care STDS. 2021 Apr;35(4):116-125. doi: 10.1089/apc.2020.0258.

ABSTRACT

Human immunodeficiency virus (HIV) infection is still a major cause of death in Thais and new cases of infection are still emerging among the key population comprising men who have sex with men (MSM), sex workers and their clients, and transgender women (TGW) and people who inject drugs. The objective of this study was to compare the incidence of HIV infection between MSM and TGW who were tested at stand-alone and mobile HIV voluntary counseling and testing (VCT) centers and to identify factors associated with HIV-positive individuals from the two services. We conducted an observational study using MSM and TGW individuals with unknown HIV status from the databases at a stand-alone center and a mobile VCT belonging to the MPlus in Chiang Mai province, Thailand. Factors associated with HIV-positive status were identified using logistic regression model. HIV VCT data were obtained for 6971 individuals at both MPlus center and mobile care unit. Among 3033 and 3938 clients tested at each facility, respectively, 168 (5.6%) and 101 (2.6%) clients were HIV positive. Individuals tested at the stand-alone centers were at a 1.91-fold higher risk of being HIV positive compared with those tested at the mobile VCT unit. Individuals who were 20-24 or >24 years old, sex workers, or sexually transmitted infection positive were more likely to be HIV positive. Our results show the beneficial effect of mobile HIV VCT facilities that enable testing of more of the at-risk population. Developing mobile VCT activities that attract a particular target population is needed to be able to reach the 90-90-90 goals. This study was approved by the Ethics Committee of the Faculty of Medicine, Chiang Mai University (0BG-2562-06418).

PMID:33835852 | DOI:10.1089/apc.2020.0258

Dentomaxillofac Radiol. 2021 Apr 9:20200578. doi: 10.1259/dmfr.20200578. Online ahead of print.

ABSTRACT

OBJECTIVE: To compare the diagnostic efficacy of different devices for visualizing digital images in detecting simulated internal root resorption (IRR).

METHODS: 26 uniradicular human teeth were sectioned along its long axis and randomly divided into two groups. Then, they were submerged in hydrochloric acid (HCl) P.A 37% at different times to make two types of defects: Type 1 (2 hours), and type 2 (3 hours). Digital periapical radiographs were acquired in three moments: before section, after section and after immersion in acid. The images were evaluated on three different devices: 27-inch iMac Desktop, 8-inch Android Tablet, and 5.5-inch iPhone 8 Plus using a 5-point scale.

RESULTS: The sensitivity and accuracy values were higher with the use of the Android Tablet, for both types of defects. For the values of the area under ROC curve, higher results were observed with the Android Tablet and lower results with the iMac, showing a significant difference (p < 0.05) when comparing the use of the iMac with the Android Tablet and iPhone 8, for type 1 defects. When comparing the different devices, in the evaluation of images of type 2 defects, the values showed no statistical difference, regardless of the device evaluated (p > 0.05).

CONCLUSIONS: The size of the lesion interferes with the detection capacity in the image. However, the use of portable devices does not impair the diagnosis of IRR, regardless of size and the dental practioners may use different devices/display, under optimal viewing conditions, to detect IRR lesions, without jeopardizing the diagnostic ability.

PMID:33835867 | DOI:10.1259/dmfr.20200578

J Laparoendosc Adv Surg Tech A. 2021 Apr 9. doi: 10.1089/lap.2021.0108. Online ahead of print.

ABSTRACT

Background: Radical prostatectomy (RP) is the first-line treatment modality for prostate cancer and can be performed using retropubic or minimally invasive techniques. New technologies such as the da Vinci robotic system and three-dimensional (3D) laparoscopic imaging system have been developed to overcome the challenges of conventional laparoscopy. This study aimed to compare the perioperative, oncological, and functional outcomes of robot-assisted laparoscopic RP (RALP) and 3D laparoscopic RP (3D LRP). Materials and Methods: The study was approved by the local ethics committee and included 65 patients (38 RALP, 27 3D LRP) who underwent RP with the diagnosis of localized prostate cancer between May 2019 and January 2020. All demographic, clinical, perioperative, pathological, and postoperative variables were recorded. Results: There was no statistically significant difference between the two groups in terms of preoperative patient characteristics. The mean operative times of the RALP and 3D LRP groups were 135.74 ± 11.51 and 165.37 ± 15.86 minutes, respectively, with a statistically significant difference between the two groups (P = .001). The mean estimated blood loss was 237 ± 71 mL in the RALP group and 257 ± 54 mL in the 3D LRP group, with no statistically significant difference between the two groups (P = .236). In the 6 months of follow-up, there was no statistically significant difference between the two groups in terms of biochemical recurrence, continence, and potency. Conclusion: RALP and 3D LRP have similar perioperative, short-term oncological and functional outcomes other than the operative time. There is a need for prospective, randomized studies with larger populations evaluating long-term oncological and functional outcomes.

PMID:33835873 | DOI:10.1089/lap.2021.0108

JCO Glob Oncol. 2021 Apr;7:486-494. doi: 10.1200/GO.20.00422.

ABSTRACT

PURPOSE: CNS relapse in patients with diffuse large B-cell lymphoma (DLBCL) is associated with poor prognosis with a median survival of about 2.5 months. Data demonstrating best prophylactic strategy remain controversial and need further definition.

PATIENTS AND METHODS: We present data of 110 patients with DLBCL treated with standard systemic therapy divided into four groups based on primary CNS prophylaxis strategy and CNS International Prognostic Index (IPI) risk categories. We compared their 3-year CNS relapse rate and overall survival in each group.

RESULTS: The CNS prophylaxis strategy consisted of intrathecal (IT) methotrexate (MTX) in group 1, high-dose (HD) MTX in group 2, combination IT and HD MTX in group 3, and IT and/or HD MTX with intensive chemotherapy in group 4. At 3 years, CNS relapse rate was 8.6% (4/46), 8.3% (1/12), 4.8% (2/42), and 18% (2/11) in groups 1-4 (P = .64), respectively. According to CNS IPI, the CNS relapse rate was 16.6%, 10.1%, and 0% in high-, intermediate-, and low-risk groups, respectively. The 3-year overall survival rate was 69%, 75%, 80%, and 45% in groups 1-4 (P = .71), respectively.

CONCLUSION: Our study while did not find statistical significance did indicate a lower incidence of CNS relapse with the addition of systemic HD MTX to IT MTX in the high-risk DLBCL population.

PMID:33835825 | DOI:10.1200/GO.20.00422

Br J Radiol. 2021 Apr 9:20200724. doi: 10.1259/bjr.20200724. Online ahead of print.

ABSTRACT

OBJECTIVES: To identify reproducible hematoma radiomics features (RFs) for use in predicting hematoma expansion (HE) in patients with acute intracerebral hemorrhage (ICH).

METHODS: For test-retest analysis, three syringes with different volumes of blood collected at the same time (to mimic homogeneous hematoma) and a phantom (FT/HK 2000; Huake, Szechwan, China) containing three cylindrical inserts were scanned seven times within 6 h on the same CT scanner. Three additional syringes with mixed blood collected at different time points (to mimic heterogeneous hematoma) were tied together with the first three syringes as well as the phantom were scanned using modified CT acquisition parameters for intra CT analysis. A coefficient of variation below 10% served as the cutoff value for reproducibility. Finally, reproducible and potentially useful RFs were used to predict HE in 144 acute ICH patients, with the area under the receiver operating characteristic curves (AUC) used to evaluate their diagnostic performance.

RESULTS: A total of 630 RFs including 18 first-order, 24 gray-level co-occurrence matrix (GLCM), 16 gray-level run length matrix (GLRLM), five neighborhood gray-tone difference matrix (NGTDM), 63 Laplacian of Gaussian (LoG), and 504 Wavelet features were evaluated. In the test-retest analysis, the percentages of reproducible RFs ranged from 42.54% (268/630) to 45.4% (286/630) for the three homogeneous hematoma samples and 79.05% (498/630) to 81.43% (513/630) for the phantom. In the intra-CT analysis, the percentages varied from 31.43% (198/630) to 42.38% (267/630) for the six hematoma samples and 48.89% (308/630) to 53.97% (340/630) for the phantom. In the in vitro experiment, 148 RFs were reproducible for all hematoma samples in both the test-retest and intra-CT analyses; however, only 80 were statistically different between homogeneous and heterogeneous hematoma samples. Finally, HE occurred in 25% (growth >6 ml, 36/144) to 31.94% (growth >3 ml or 33%, 46/144) of the patients. The AUCs in predicting HE ranged from 0.625 to 0.703.

CONCLUSIONS: Only a few CT-based RFs from the in vitro hematoma were reproducible and can distinguish between homogeneous and heterogeneous hematomas. The use of RFs alone to predict HE in acute ICH showed only a moderate performance.

ADVANCES IN KNOWLEDGE: Using an in vitro experiment and clinical validation, this study demonstrated for the first time that CT-based hematoma RFs can be used to predict HE in acute ICH; nonetheless, only a few RFs are reproducible and can be used for prediction.

PMID:33835831 | DOI:10.1259/bjr.20200724

Eur J Trauma Emerg Surg. 2021 Apr 9. doi: 10.1007/s00068-021-01655-7. Online ahead of print.

ABSTRACT

PURPOSE: Patients with surgically treated acetabular fractures using extensive dissection of hip muscles demonstrate an incomplete biomechanical recovery and limited joint mobility during movement. The purpose of this study was to evaluate the early biomechanical outcome in a series of patients with acetabular fractures treated using the less invasive anatomical pararectus approach.

METHODS: Eight patients (48 ± 14 years, BMI 25.8 ± 3 kg/m²) were investigated 3.8 ± 1.3 months after surgery and compared to matched controls (49 ± 13 years, BMI 26 ± 2.8 kg/m²). Trunk and lower extremity kinematics and kinetics during gait and stair climb were calculated. SF-12 and the Merle d’Aubigné score were used for functional evaluation. Statistical analysis was conducted using Mann-Whitney test and Student’s t test. Effect sizes were calculated using Cohen’s d.

RESULTS: No group differences for lower extremity kinematics during walking and stair climbing were found. During walking, patients showed significant reductions (p < 0.05) of the vertical ground reaction force (8%) and knee and hip extension moments (29 and 27%). Ipsilateral trunk lean was significantly increased by 3.1° during stair descend while reductions of vertical ground reaction force were found for stair ascend (7%) and descend (20%). Hip extension moment was significantly reduced during stair descend by 37%. Patients revealed acceptable SF-12 physical and mental component outcomes and a good rating for the Merle d’Aubigné score (15.9 ± 1.7).

CONCLUSION: Patients showed some biomechanical restrictions that can be related to residual deficits in weight bearing capacity and strength of the hip muscles. In contrast, an immediate recovery of mobility was achieved by preserving lower extremity and pelvic movement. Therefore, the pararectus approach can serve as a viable strategy in the surgical treatment of acetabular fractures.

CLINICAL TRIAL: Trial registration number DRKS00011308, 11/14/2016, prospectively registered.

PMID:33835187 | DOI:10.1007/s00068-021-01655-7