bluuebunny/crossref_metadata_2025 huggingface dataset:
Triglyceride-glucose index predicts adverse cardiovascular events in patients with diabetes and acute coronary syndrome
Authors: Wang Le , Cong Hong-liang , Zhang Jing-xia , Hu Yue-cheng , Wei Ao , Zhang Ying-yi , Yang Hua , Ren Li-bin , Qi Wei , Li Wen-yu , Zhang Rui , Xu Jing-han
Published: June 2020

Background

The triglyceride-glucose index (TyG index) has been regarded as a reliable alternative marker of insulin resistance and an independent predictor of cardiovascular outcomes. Whether the TyG index predicts adverse cardiovascular events in patients with diabetes and acute coronary syndrome (ACS) remains uncertain. The aim of this study was to investigate the prognostic value of the TyG index in patients with diabetes and ACS.

Methods

A total of 2531 consecutive patients with diabetes who underwent coronary angiography for ACS were enrolled in this study. Patients were divided into tertiles according to their TyG index. The primary outcomes included the occurrence of major adverse cardiovascular events (MACEs), defined as all-cause death, non-fatal myocardial infarction and non-fatal stroke. The TyG index was calculated as the ln (fasting triglyceride level [mg/dL] × fasting glucose level [mg/dL]/2).

Results

The incidence of MACE increased with TyG index tertiles at a 3-year follow-up. The Kaplan–Meier curves showed significant differences in event-free survival rates among TyG index tertiles (P = 0.005). Multivariate Cox hazards regression analysis revealed that the TyG index was an independent predictor of MACE (95% CI 1.201–1.746; P < 0.001). The optimal TyG index cut-off for predicting MACE was 9.323 (sensitivity 46.0%; specificity 63.6%; area under the curve 0.560; P = 0.001). Furthermore, adding the TyG index to the prognostic model for MACE improved the C-statistic value (P = 0.010), the integrated discrimination improvement value (P = 0.001) and the net reclassification improvement value (P = 0.019).

Conclusions

The TyG index predicts future MACE in patients with diabetes and ACS independently of known cardiovascular risk factors, suggesting that the TyG index may be a useful marker for risk stratification and prognosis in patients with diabetes and ACS.
Generalizability of sodium-glucose co-transporter-2 inhibitors cardiovascular outcome trials to the type 2 diabetes population: a systematic review and meta-analysis
Authors: Castellana Marco , Procino Filippo , Sardone Rodolfo , Trimboli Pierpaolo , Giannelli Gianluigi
Published: June 2020

Background

Cardiovascular outcome trials of sodium-glucose co-transporter-2 inhibitors (SGLT2i CVOTs) found the agents to be associated with clinical benefits in terms of cardiovascular and renal outcomes. We performed a meta-analysis to assess and compare the overall prevalence of eligibility for the enrollment criteria of CANVAS, DECLARE-TIMI 58, EMPA-REG OUTCOME, and VERTIS-CV among unselected patients with type 2 diabetes.

Methods

This meta-analysis was registered in PROSPERO (CRD42020172032). PubMed, CENTRAL, Scopus and Web of Science were researched in March 2020. Studies evaluating the prevalence of eligibility for each SGLT2i CVOT were selected. Endpoints were estimated using a random-effects model.

Results

Five studies, evaluating 1,703,519 patients with type 2 diabetes, were included. Overall, the prevalence of eligible patients according to the enrollment criteria of CANVAS, DECLARE-TIMI 58, EMPA-REG OUTCOME, and VERTIS-CV was 36.4%, 49.5%, 17.0% and 19.0%, respectively. In head-to-head comparisons, DECLARE-TIMI 58 was associated with the highest odds of eligibility (1.74 versus CANVAS, 5.15 versus EMPA-REG OUTCOME and 4.81 versus VERTIS-CV), followed by CANVAS and EMPA-REG OUTCOME/VERTIS-CV. A high heterogeneity was found for all the outcomes.

Conclusions

The present review showed that a considerable number of patients counseled in clinical practice could have been eligible for SGLT2i CVOTs. Particularly, dapagliflozin was shown to be the SGLT2i with the largest generalizability of findings from its CVOT according to the odds ratio of eligibility for the enrollment criteria among unselected patients with type 2 diabetes. Further country- or region-specific studies are needed to confirm the applicability of our results.
Type 2 diabetes mellitus increases the mortality risk after acute coronary syndrome treated with coronary artery bypass surgery
Authors: Ram Eilon , Sternik Leonid , Klempfner Robert , Iakobishvili Zaza , Fisman Enrique Z. , Tenenbaum Alexander , Zuroff Elchanan , Peled Yael , Raanani Ehud
Published: June 2020

Background

Type 2 diabetes mellitus (DM) is a risk factor for cardiovascular diseases and is common among patients undergoing coronary artery bypass grafting (CABG) surgery. The main objective of our study was to investigate the impact of DM type 2, and its treatment subgroups, on short- and long-term mortality in patients with acute coronary syndrome (ACS) who undergo CABG.

Methods

The study included 1307 patients enrolled from the biennial Acute Coronary Syndrome Israeli Survey between 2000 and 2016, who were hospitalized for ACS and underwent CABG. Of them, 527 (40%) patients were with and 780 (60%) were without DM.

Results

Compared with the non-diabetic group, the diabetic group of patients comprised more women and had more comorbidities such as hypertension, dyslipidemia, renal impairment, peripheral vascular disease and prior ischemic heart disease. Overall 30-day mortality rate was similar between DM and non-DM patients (4.2% vs. 4%, p = 0.976). Ten-year mortality rate was higher in DM compared with non-diabetic patients (26.6% vs. 17.7%, log-rank p < 0.001), and higher in the subgroup of insulin-treated patients compared to non-insulin treated patients (31.5% vs. 25.6%, log-rank p = 0.019). Multivariable analysis showed that DM increased the mortality hazard by 1.61-fold, and insulin treatment among the diabetic patients increased the mortality hazard by 1.57-fold.

Conclusions

While type 2 DM did not influence the in-hospital mortality hazard, we showed that the presence of DM among patients with ACS referred to CABG, is a powerful risk factor for long-term mortality, especially when insulin was included in the diabetic treatment strategy.
Low expression of organic anion-transporting polypeptide 1B3 predicts a poor prognosis in hepatocellular carcinoma
Authors: Chen Shihan , Li Kun , Jiang Jiayun , Wang Xiaofei , Chai Yuelong , Zhang Chang , Deng Qingsong , Shuai Ling , Feng Kai , Ma Kuansheng , Zhang Leida
Published: June 2020

Objective

To detect the expression level of organic anion-transporting polypeptide 1B3 (OATP1B3) in hepatocellular carcinoma (HCC) and to determine the relationship between OATP1B3 expression, clinicopathological features, and prognosis.

Methods

Immunohistochemical (IHC) staining was performed to detect the expression of OATP1B3 in 131 HCC specimens and in 89 adjacent nontumorous tissues. Moreover, the expression levels of OATP1B3 in 30 pairs of tumor and matched adjacent nontumorous tissues were detected by quantitative real-time polymerase chain reaction, and 34 pairs of tumor and matched adjacent nontumorous tissues were detected by Western blotting. The χ2 test was applied to analyze the correlation between OATP1B3 expression and the clinical parameters of HCC patients. The prognostic value of OATP1B3 in HCC patients was estimated by Kaplan-Meier survival analysis and the Cox stepwise proportional hazards model.

Results

Compared with that in adjacent nontumorous tissues (25.8%, 23/89), OATP1B3 expression was significantly downregulated in tumor tissues (59.5%, 78/131) (P < 0.0001). Moreover, OATP1B3 expression was markedly correlated with tumor size, recurrence, tumor differentiation, and tumor node metastasis (TNM) stage (P < 0.05 for each). However, age, sex, tumor capsule status, HBsAg, cirrhosis, tumor number, vascular invasion, and serum alpha fetoprotein were not associated with OATP1B3 expression. The overall survival (OS) and disease-free survival (DFS) of HCC patients who had high expression of OATP1B3 were significantly longer than those of patients with low expression (33.0% vs 12.9%, P = 0.001; 18.8% vs 5.3%, P < 0.0001). Cox multivariate analysis showed that OATP1B3, invasion, and TNM stage (P < 0.05 for each) were independent prognostic factors of OS in HCC patients and that OATP1B3 and TNM stage (both P < 0.05) were independent prognostic factors of DFS in HCC patients.

Conclusions

The expression of OATP1B3 in HCC patients was significantly lower than that in adjacent nontumorous tissues. OATP1B3 expression may be a potential prognostic marker in HCC patients.
Chromosome 17p13 deletion is associated with an aggressive tumor phenotype in clear cell renal cell carcinoma
Authors: Eichenauer Till , Shadanpour Navid , Kluth Martina , Göbel Cosima , Weidemann Sören , Fraune Christoph , Büscheck Franziska , Hube-Magg Claudia , Möller-Koop Christina , Dahlem Roland , Fisch Margit , Rink Michael , Riechardt Silke , Burandt Eike , Bernreuther Christian , Minner Sarah , Simon Ronald , Sauter Guido , Wilczak Waldemar , Clauditz Till
Published: June 2020

Background

Deletions of 17p13 recurrently occur in renal cell carcinoma (RCC) but their prognostic role seems to be uncertain.

Methods

To determine prevalence, relationship with tumor phenotype, and patient prognosis, a tissue microarray containing samples from 1809 RCCs was evaluated using dual labeling fluorescence in situ hybridization (FISH) with 17p13 and chromosome 17 centromere probes.

Results

A 17p13 deletion was found in 72 of 1429 interpretable tumors. The frequency of 17p13 deletions varied greatly between RCC subtypes and was highest in chromophobe RCC (24/72; 33.3%). 17p13 deletions were also found in 35 (3.7%) of 946 clear cell RCC, 9 (4.3%) of 208 papillary RCC, 1 of 121 oncocytomas (0.8%), as well as in several rare cases of comprising 1 of 7 Xp11.2 translocation cancers, 1 of 3 collecting duct carcinomas, and 1 of 20 not otherwise specified (NOS) carcinomas. In clear cell carcinomas, 17p13 deletions revealed a strong and consistent association with higher Fuhrman, ISUP, and Thoenes grade (p < 0.0001 each), and linked to advanced tumor stage (p = 0.0168), large tumor diameter (p = 0.0004), distant metastases (p = 0.0077), cancer-specific survival (p = 0.0391), and recurrence-free survival (p = 0.0072). In multivariate analysis, 17p13 deletions showed in clear cell RCC a dependent prognostic role for established clinical-pathological parameters.

Conclusion

17p13 deletions have a dual role in RCC. They are associated with disease progression in clear cell RCC and possibly other subtypes and they are linked to the development of chromophobe RCC—a subtype with a particularly favorable prognosis.
Macrofollicular variant of papillary thyroid carcinoma with metastasis to femur
Authors: Candanedo-Gonzalez Fernando , Rodriguez-Orihuela Diana , Arista-Nasr Julian
Published: June 2020

Background

Macrofollicular variant of papillary thyroid carcinoma (MFV-PTC) is a rare subtype with histological features and an indolent clinical course that can be confused with nodular goiter or follicular adenoma. However, on rare occasions it may show more aggressive biological behavior. Only two cases of MFV-PTC with bone metastases have been reported previously. We describe the clinical-pathological characteristics of a man with MFV-PTC that developed femur metastasis. This the first case of MFV-PTC with femur metastases diagnosed histologically by means of an image-guided core needle biopsy in English literature.

Case presentation

A 33-year-old man presented two years earlier with swelling in the right neck associated with weight loss and pain in the left knee. Neck ultrasonography showed hyperechogenic and hypogenic nodular images in the thyroid’s right lobe. A fine needle aspiration biopsy specimen was initially interpreted as nodular hyperplasia. A CT showed a large tumor involving right thyroid lobe with trachea and vascular structures displaced to the right, and a total thyroidectomy was performed. Subsequently, a MRI of the knee confirmed the presence of a destructive tumor in the femur. A guided core-needle biopsy of the knee tumor showed the presence of metastatic MFV-PTC. Re-assessment of the histology from thyroidectomy was also consistent with MFV-PTC. A whole-body 18F-FDG PET/CT showed presence of lesions in the left anterior costal arch, metaphysis of the left femur and in the sternum handle. Therefore, he received 200 mCi radioactive iodine, and 40 Gy of radiotherapy to left costal arches and knee, which decreased his symptoms. Currently, after 10 months of follow-up, the patient is alive with bone tumor activity.

Conclusions

Our case supports the view that, on rare ocassions, MFV-PTC may show a more aggressive biological behavior than expected. The synchronous or asynchronous presence of one or more bone lesions, should raise the suspicion of metastasis. Given the suspicion, it is necessary to take a biopsy to confirm histologically. Only a careful analysis of the architectural and cytological characteristics of goiter or hyperplastic nodules will allow to recognize this rare variety of carcinoma.
Elevated serum TSH concentrations are associated with higher BMI Z-scores in southern Iranian children and adolescents
Authors: Habib Ashkan , Molayemat Mohadeseh , Habib Asadollah
Published: June 2020

Background

Subclinical hypothyroidism is defined as elevated TSH levels while T4 or FT4 levels are normal. Elevated TSH levels are linked with obesity in adults. In a recent meta-analysis in Iran, 6.1% of children below 18 had obesity. Due to the low number of studies on the subject in children we, designed the study to assess the relation between BMI Z-score and TSH levels in children and adolescence.

Method

This cross-sectional study was performed in a pediatric endocrinology clinic in Shiraz. Children aged between 2 to 18 years that came to the clinic for routine growth assessment follow up from January till April 2018 were considered. 850 children including 365 boys and 485 girls were included.

Results

Prevalence of subclinical hypothyroidism is increased in higher BMI groups. 9.9, 13.8, 17.2 and 20.5% of underweight, healthy weight, overweight and obese had subclinical hypothyroidism respectively. Obese and overweight participants had higher odds of subclinical hypothyroidism than those who were not (OR:1.649, P = 0.010, CI95% 1.126–2.413). On the other hand, Subclinical hypothyroid participants had higher odds of overweight or obesity than those who were euthyroid (OR:1.650, P = 0.010, CI95% 1.128–2.413). When TSH is set as a dependent value, TSH level is increased (β = 0.126, r = 0.125, P = 0.001) with an increase in BMI Z-score. When BMI Z-score is set as a dependent value, BMI Z-score is increased (β = 0.113, r = 0.243, P = 0.001) with an increase in TSH level.

Conclusion

BMI Z-score and elevated TSH levels are positively correlated however studies should be performed on establishing the causality.
The dynamics of biomarkers across the clinical spectrum of Alzheimer’s disease
Authors: Hadjichrysanthou Christoforos , Evans Stephanie , Bajaj Sumali , Siakallis Loizos C. , McRae-McKee Kevin , de Wolf Frank , Anderson Roy M. ,   the Alzheimer’s Disease Neuroimaging Initiative
Published: June 2020

Background

Quantifying changes in the levels of biological and cognitive markers prior to the clinical presentation of Alzheimer’s disease (AD) will provide a template for understanding the underlying aetiology of the clinical syndrome and, concomitantly, for improving early diagnosis, clinical trial recruitment and treatment assessment. This study aims to characterise continuous changes of such markers and determine their rate of change and temporal order throughout the AD continuum.

Methods

The methodology is founded on the development of stochastic models to estimate the expected time to reach different clinical disease states, for different risk groups, and synchronise short-term individual biomarker data onto a disease progression timeline. Twenty-seven markers are considered, including a range of cognitive scores, cerebrospinal (CSF) and plasma fluid proteins, and brain structural and molecular imaging measures. Data from 2014 participants in the Alzheimer’s Disease Neuroimaging Initiative database is utilised.

Results

The model suggests that detectable memory dysfunction could occur up to three decades prior to the onset of dementia due to AD (ADem). This is closely followed by changes in amyloid-β CSF levels and the first cognitive decline, as assessed by sensitive measures. Hippocampal atrophy could be observed as early as the initial amyloid-β accumulation. Brain hypometabolism starts later, about 14 years before onset, along with changes in the levels of total and phosphorylated tau proteins. Loss of functional abilities occurs rapidly around ADem onset. Neurofilament light is the only protein with notable early changes in plasma levels. The rate of change varies, with CSF, memory, amyloid PET and brain structural measures exhibiting the highest rate before the onset of ADem, followed by a decline. The probability of progressing to a more severe clinical state increases almost exponentially with age. In accordance with previous studies, the presence of apolipoprotein E4 alleles and amyloid-β accumulation can be associated with an increased risk of developing the disease, but their influence depends on age and clinical state.

Conclusions

Despite the limited longitudinal data at the individual level and the high variability observed in such data, the study elucidates the link between the long asynchronous pathophysiological processes and the preclinical and clinical stages of AD.
Simultaneous determination of the metabolites of the herbicide metazachlor in agricultural crops by LC–MS/MS
Authors: Park Ji-Su , Lee Han Sol , Cho Sung Min , Lee Su Jung , Shin Hye-Sun , Shim Jae-Han , Yun Sang Soon , Jung Yong-hyun , Oh Jae-ho
Published: June 2020

To manage the safety of the herbicide metazachlor, analytical methods are required for the determination of metazachlor metabolites in agricultural crops. Herein, a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for the simultaneous determination of metazachlor metabolites (479M04, 479M08, and 479M16) in various agricultural commodities. After extraction using acetonitrile and adjusting the pH to 3, the samples were purified using a hydrophilic–lipophilic balance cartridge. The matrix-matched calibration curves (0.002–0.2 μg/mL) were linear (r2 > 0.99). For validation, recovery tests were carried out at three fortification levels (limit of quantification (LOQ), 10 LOQ, and 50 LOQ) in various agricultural samples. The recoveries of 479M04, 479M08, and 479M16 were 79.6–113.0, 76.9–97.7, and 79.1–102.1%, respectively, with relative standard deviation values of less than 17.0%. Furthermore, inter-laboratory testing was conducted to validate the method. All the values corresponded to the criteria of both the CODEX (CAC/GL 40-1993, 2003) and Ministry of Food and Drug Safety guidelines. Therefore, the proposed LC–MS/MS method can be used as an analytical method for the determination of metazachlor.
Climate mediates continental scale patterns of stream microbial functional diversity
Authors: Picazo Félix , Vilmi Annika , Aalto Juha , Soininen Janne , Casamayor Emilio O. , Liu Yongqin , Wu Qinglong , Ren Lijuan , Zhou Jizhong , Shen Ji , Wang Jianjun
Published: June 2020

Background

Understanding the large-scale patterns of microbial functional diversity is essential for anticipating climate change impacts on ecosystems worldwide. However, studies of functional biogeography remain scarce for microorganisms, especially in freshwater ecosystems. Here we study 15,289 functional genes of stream biofilm microbes along three elevational gradients in Norway, Spain and China.

Results

We find that alpha diversity declines towards high elevations and assemblage composition shows increasing turnover with greater elevational distances. These elevational patterns are highly consistent across mountains, kingdoms and functional categories and exhibit the strongest trends in China due to its largest environmental gradients. Across mountains, functional gene assemblages differ in alpha diversity and composition between the mountains in Europe and Asia. Climate, such as mean temperature of the warmest quarter or mean precipitation of the coldest quarter, is the best predictor of alpha diversity and assemblage composition at both mountain and continental scales, with local non-climatic predictors gaining more importance at mountain scale. Under future climate, we project substantial variations in alpha diversity and assemblage composition across the Eurasian river network, primarily occurring in northern and central regions, respectively.

Conclusions

We conclude that climate controls microbial functional gene diversity in streams at large spatial scales; therefore, the underlying ecosystem processes are highly sensitive to climate variations, especially at high latitudes. This biogeographical framework for microbial functional diversity serves as a baseline to anticipate ecosystem responses and biogeochemical feedback to ongoing climate change.
Fast imaging of time-domain airborne EM data using deep learning technology
Authors: Li Jinfeng , Liu Yunhe , Yin Changchun , Ren Xiuyan , Su Yang
Published: June 2020

Due to the huge amount of data generated by time-domain airborne electromagnetic (AEM) systems, conductivity depth imaging methods are widely used to help in the interpretation of these data because they can be generated quickly and easily. We have introduced a new imaging method generated using a deep neural network. The network structure combines four convolutional neural networks with a long short-term memory technique and adopts an error back-propagation scheme to update the parameters. A deep hierarchical structure is used to extract and store the complex nonlinear relationship between the model and electromagnetic (EM) responses, creating results close to 1D inversions. To check the effectiveness, we have examined our algorithm on synthetic and survey AEM data. The imaging result shows that this method, when using reasonable network parameters, can not only image well at high speed, but the method also is not very sensitive to noise. Another advantage of this method is that once the training is completed on a well-distributed training set, the network can be used without any changes to process other data sets from an identically configured AEM system.
Three-dimensional magnetotelluric numerical simulation of realistic geologic models
Authors: Ansari SeyedMasoud , Schetselaar Ernst , Craven James , Farquharson Colin
Published: June 2020

We have developed a workflow for constructing realistic mesh-based magnetotelluric (MT) models from 3D geologic models. The routine is developed for unstructured meshes that adapt to the complex shapes of geologic bodies including 3D surfaces and volumes in realistic modeling scenarios. The methodology is applied to the complexly altered Lalor volcanogenic massive sulfide deposit in Manitoba, Canada. The host rock envelope of the Lalor deposit is compartmentalized into lithostratigraphic units leading to a watertight model. This model then is meshed into unstructured tetrahedral meshes suitable for synthetic geophysical modeling of the MT method. Subsequently, two 3D resistivity models are generated from wireline logs: (1) a host rock background model in which each tetrahedral cell is attributed with the average resistivity of each lithostratigraphic unit and (2) a heterogeneous background-ore model in which the resistivity values of the cells are resampled from a 3D curvilinear grid model, generated by computing sequential Gaussian simulations from the resistivity data for each unit of a 3D lithofacies model produced by categorical kriging. To calculate the synthetic response of this model for MT, a numerical-modeling code is developed based on solving the vector-scalar potential formulation of the electromagnetic diffusion equation using the finite-element method on unstructured meshes. After validating the numerical method for the Commemi test model, the MT response of the Lalor model is investigated. A reasonable agreement is observed between the survey field data and the data synthesized from our constructed heterogeneous model. Using an investigation of the inductive and galvanic parts, we conclude with the ideal frequency range for detecting the ore deposit. We also conclude with and visualize the importance of regional-scale alteration zones around the ore deposits and model inhomogeneities in boosting the detectability of the ore formations through feeding electrical currents as a result of galvanic field dominance at depth.
Inverse modeling constrained by potential field data, petrophysics, and improved geologic mapping: A case study from prospective northwest Tasmania
Authors: Eshaghi Esmaeil , Reading Anya M. , Roach Michael , Duffett Mark , Bombardieri Daniel , Cracknell Matthew J. , Everard John L. , Cumming Grace , Kuhn Stephen
Published: June 2020

The Heazlewood-Luina-Waratah area is a prospective region for minerals in northwest Tasmania, Australia, associated with historically important ore deposits related to the emplacement of granite intrusions and/or ultramafic complexes. The geology of the area is poorly understood due to the difficult terrain and dense vegetation. We have constructed an initial high-resolution 3D geologic model of this area using constraints from geologic maps and geologic and geophysical cross sections. This initial model is improved upon by integrating results from 3D geometry and physical property inversion of potential field (gravity and magnetic) data, petrophysical measurements, and updated field mapping. Geometry inversion reveals that the Devonian granites in the south are thicker than previously thought, possibly connecting to deep sources of mineralization. In addition, we identified gravity anomalies to the northeast that could be caused by near-surface granite cupolas. A newly discovered ultramafic complex linking the Heazlewood and Mount Stewart Ultramafic Complexes in the southwest also has been modeled. This implies a greater volume of ultramafic material in the Cambrian successions and points to a larger obducted component than previously thought. The newly inferred granite cupolas and ultramafic complexes are targets for future mineral exploration. Petrophysical property inversion reveals a high degree of variation in these properties within the ultramafic complexes indicating a variable degree of serpentinization. Sensitivity tests suggest maximum depths of 2–3 km for the contact aureole that surrounds major granitic intrusions in the southeast, whereas the Heazlewood River complex is likely to have a deeper source up to 4 km. We have demonstrated the value of adding geologic and petrophysical constraints to 3D modeling for the purpose of guiding mineral exploration. This is particularly important for the refinement of geologic structures in tectonically complex areas that have lithology units with contrasting magnetic and density characteristics.
Rational approximation of P-wave kinematics — Part 1: Transversely isotropic media
Authors: Abedi Mohammad Mahdi
Published: June 2020

In seismic data processing and several wave propagation modeling algorithms, the phase velocity, group velocity, and traveltime equations are essential. To have these equations in explicit form, or to reduce algebraic complexity, approximation methods are used. For the approximation of P-wave kinematics in acoustic transversely isotropic media, we have developed a new flexible 2D functional equation in a continued fraction form. Using different orders of the continued fraction, we obtain different approximations for (1) phase velocity as a function of phase direction, (2) group velocity as a function of group direction, and (3) traveltime as a function of offset. Then, we use them in the approximation of the group direction as a function of phase direction, and phase direction as a function of group direction. The proposed approximations have a rational form, which is considered algebraically simple and computationally efficient. The used continued fraction form rapidly converges to exact kinematics. By introducing the optimal ray into our approximations and using it for parameter definition, the convergence becomes faster, so the accuracy of the existing most accurate approximations is available by the third order, and new most accurate approximations are obtained by the fourth order of the proposed general form. The error of the most accurate version of the proposed approximations is below 0.001% for moderate anisotropic models with an anellipticity parameter up to 0.3. This high accuracy is considered to be attractive in practical implementations that use the kinematic equations and their derivatives.
Sedimentary characteristics of muddy deposits in sandy braided fluvial system: A case study from outcrops of the Jurassic Yungang Formation in the Datong Basin, Central China
Authors: Liu Yuming , Dou Luxing , Ren Xiaoxu , Hou Jiagen
Published: June 2020

The sandbodies within braided fluvial deposits are important reservoirs for the oil fields in China, and they usually have complex sedimentary architecture. A lot of research has been concentrated on characterizing the architecture of the sandbodies. Based on the observation that muddy deposits are commonly well preserved in fluvial deposits, we find that understanding the contact relationship between the muddy deposits and surrounding sand bodies can help characterize the depositional process of sandy braided fluvial systems. We have determined the effectiveness of this idea by characterizing a well-exposed outcrop of sandy braided fluvial system in the Datong Basin, Shanxi Province of China. We first define six muddy lithofacies by integrating the thickness of the muddy deposits, the morphology of the muddy deposit, and the lithofacies of surrounding sand deposits. The six muddy lithofacies include floodplain muddy deposits between intermittent channel complex, lateral covering muddy deposits and fall-silt seam muddy deposits between migrated bar complex, muddy gravel deposits in erosional bar complex, and channel-fill muddy deposits and gully-fill muddy deposits in abandoned bar complex. We then analyze the depositional environments according to the defined muddy lithofacies. We finally build the architecture of the outcrops by integrating the lithofacies of sand deposits and evolution of the depositional environments deduced from the muddy lithofacies.
Natural fractures in the Triassic tight sandstones of the Dongpu Depression, Bohai Bay Basin, eastern China: The key to production
Authors: Wang Zhaosheng , Zeng Lianbo , Luo Zhouliang , Zu Kewei , Lao Haigang , Meng Ningning
Published: June 2020

Natural fractures are identified as high-quality storage space and seepage channels for the Triassic tight sandstone reservoirs in the Dongpu Depression, playing an important role in tight sandstone oil production. We have evaluated natural fracture growth at different scales using outcrops, cores, thin sections, and imaging logs and analyzed the correlation between fractures and crude oil production capacity with production data. Results show that natural fractures primarily are distributed in fine sandstones and siltstones, which mostly are shear fractures of near east–west and northeast–southwest strikes. The natural fractures of near east–west strikes generally are parallel to the present-day maximum horizontal principal stress with the biggest apertures and the highest permeability, which are the main seepage channels, next being the fractures of northeast–southwest strike. The natural fractures of near east–west strikes also are the most important contributors to the crude oil production in the Triassic tight sandstones of the Dongpu Depression. The intensity, permeability, and direction of natural fractures govern the crude oil productivity in the per-unit sandstone thickness.
EXPERIMENTAL EVALUATION OF ULTRASONIC VELOCITIES AND ANISOTROPY IN THE TUSCALOOSA MARINE SHALE FORMATION
Authors: Ahmadov Jamal , Mokhtari Mehdi
Published: June 2020

Tuscaloosa Marine Shale (TMS) formation is a clay- and organic-rich emerging shale play with a considerable amount of hydrocarbon resources. Despite the substantial potential, there have been only a few wells drilled and produced in the formation over the recent years. The analyzed TMS samples contain an average of 50 wt% total clay, 27 wt% quartz and 14 wt% calcite and the mineralogy varies considerably over the small intervals. The high amount of clay leads to pronounced anisotropy and the frequent changes in mineralogy result in the heterogeneity of the formation. We studied the compressional (VP) and shear-wave (VS) velocities to evaluate the degree of anisotropy and heterogeneity, which impact hydraulic fracture growth, borehole instabilities, and subsurface imaging. The ultrasonic measurements of P- and S-wave velocities from five TMS wells are the best fit to the linear relationship with R2 = 0.84 in the least-squares criteria. We observed that TMS S-wave velocities are relatively lower when compared to the established velocity relationships. Most of the velocity data in bedding-normal direction lie outside constant VP/VS lines of 1.6–1.8, a region typical of most organic-rich shale plays. For all of the studied TMS samples, the S-wave velocity anisotropy exhibits higher values than P-wave velocity anisotropy. In the samples in which the composition is dominated by either calcite or quartz minerals, mineralogy controls the velocities and VP/VS ratios to a great extent. Additionally, the organic content and maturity account for the velocity behavior in the samples in which the mineralogical composition fails to do so. The results provide further insights into TMS Formation evaluation and contribute to a better understanding of the heterogeneity and anisotropy of the play.
Natural fractures in deep tight gas sandstone reservoirs in the thrust belt of the southern Junggar Basin, northwestern China
Authors: Liu Guoping , Zeng Lianbo , Wang Xiaojun , Ostadhassan Mehdi , Wang Zhenlin , Mao Zhe , Tie Qi
Published: June 2020

The development of natural fractures is a significant characteristic of the Jurassic deep tight sandstone reservoirs in the thrust belt of the southern Junggar Basin, and these reservoirs have a great potential for natural gas resources. Based on the analyses of outcrops, cores, thin sections, and other laboratory data, natural fractures in these reservoirs are mainly tectonic ones, which appear in groups and vary in scale, dip angle, and density. We have classified fractures in thin sections into intragranular, grain boundary, and transgranular ones depending on their relationship with minerals grains. Almost 58% of the whole fracture population is opening-mode fractures, and calcite is the main filling mineral for the remaining ones. Fracture apertures vary based on their types, where transgranular fractures are the widest, followed by grain boundary and intragranular ones. Lithology, rock mechanical mechanics layers, and structures control the development of natural fractures. Fractures are more frequent in siltstone and fine sandstone. Sandstones with larger mineral grains are more likely to develop grain boundary and intragranular fractures. Intralayer fractures are the dominant ones, which intersect the rock mechanics interface at high angles or perpendicularly. The linear density of these fractures decreases when the thickness of the rock-mechanics layer increases. Furthermore, fractures have a higher degree of development in the hanging wall of the faults, with the degree decreasing when the distance from the fault plane increases. Additionally, the development degree of fractures in the damage zone is better than the adjacent rocks, and the width of damage zones is a function of the amount of fault displacement.
Direct differentiation of cord blood derived mesenchymal stem cells into keratinocytes without feeder layers and cAMP inducers
Authors: Ghauri Ayesha Kashmala , Wahid Mohsin , Mirza Talat , Ainuddin Jahan Ara
Published: June 2020

Objectives: The purpose of our study was isolation of umbilical cord blood derived mesenchymal stem (UCB-MSCs), their direct differentiation towards keratinocytes without using feeder layers, cAMP inducers and hormones known for morphological maintenance and proliferation of keratinocytes and characterization of UCB-MSCs through flowcytometry and keratinocytes through immunofluorescence.

Methods: We have isolated and cultured UCB-MSCs (n=4) following critical parameters for successful isolation like sample processing within an hour of collection, gestational age not more than 38 weeks, no co-morbid and blood volume at least 80 ml. Cord blood mononuclear cells were isolated through ficoll based density-gradient centrifugation then cultured to isolate MSCs, defined by minimum criteria of International Society for Cellular Therapy. UCB-MSCs were then differentiated directly into keratinocytes. Differentiation was confirmed by morphology and characterized through immunofluorescence staining. UCB samples were collected from gynae/obstetric ward of OJHA campus under sterile conditions and processed at Stem cells and Regenerative medicine Lab, Dow Research Institute of Biotechnology and Biomedical Sciences, Ojha campus. The total duration of study was approximately 12 months.

Results: We have successfully isolated UCB-MSCs that were plastic adherent, spindle shaped, showed trilineage mesodermal differentiation potential and were positive for CD90, CD73 and CD105 and negative for CD34 markers. UCB-MSCs were directly differentiated towards keratinocytes without using cAMP inducers, hormones or feeder layers. Differentiated keratinocytes attained typical honeycomb morphology and were stained positive on immunofluorescence for anti-pan cytokeratin antibody.

Conclusion: Our study concludes possibility of direct differentiation of isolated and cultured UCB-MSCs into keratinocytes without using feeder layers and conventional keratinocyte culture media.

doi: https://doi.org/10.12669/pjms.36.5.1566

How to cite this:Ghauri AK, Wahid M, Mirza T, Uddin JAA. Direct differentiation of cord blood derived mesenchymal stem cells into keratinocytes without feeder layers and cAMP inducers. Pak J Med Sci. 2020;36(5):946-951. doi: https://doi.org/10.12669/pjms.36.5.1566

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Fetomaternal outcome in patients with placenta previa
Authors: Wasim Tayyiba , Bushra Natasha , Riaz Saher , Iqbal Hafiza Iqra
Published: June 2020

Objectives: To assess maternal and fetal morbidity associated with placenta previa and morbidly adherent placenta (MAP).

Methods: All patients with placenta previa who delivered in services hospital from April 1, 2017 to March 31, 2019 were included. Maternal and fetal outcomes were compared amongst patients with placenta previa and MAP.

Results: Total of 8002 patients delivered with 152 (1.9%)diagnosed as placenta previa and 56 (36.8%) amongst them had MAP. One hundred thirty-one out of One hundred fifty-two (86.1%) of our patients were booked. Increased number of caesarean section, multi parity and anterior placenta had significant association with MAP (p<0.0001). Maternal morbidity in terms of postpartum hemorrhage >2000ml, caesarean hysterectomy, number of blood transfusions, bladder injury, need for ICU admission was significantly more in patients with MAP (p<0.0001). Case fatality was 3% with two maternal deaths in MAP and none in placenta previa. Fetal outcome was good in both groups as gestational age at delivery was 36 weeks or more, birth weight was ≥ 2.5 kg and >6 APGAR score (p<0.05). Two neonatal deaths occurred in MAP and one in placenta previa owing to prematurity.

Conclusion: MAP is a dreadful complication of placenta previa with increased maternal morbidity. Regular antenatal care with adequate arrangement of blood transfusion and multidisciplinary approach can reduce maternal mortality.

doi: https://doi.org/10.12669/pjms.36.5.1647

How to cite this:Wasim T, Bushra N, Riaz S, Iqbal HI. Fetomaternal outcome in patients with placenta previa. Pak J Med Sci. 2020;36(5):952-957.  doi: https://doi.org/10.12669/pjms.36.5.1647

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Challenges faced by the Medical Editors in COVID19 Pandemic era
Authors: Jawaid Shaukat Ali , Jawaid Masood
Published: June 2020

doi: https://doi.org/10.12669/pjms.36.5.3009

How to cite this:Jawaid SA, Jawaid M. Challenges faced by the Medical Editors in COVID19 Pandemic era. Pak J Med Sci. 2020;36(5):855-856.   doi: https://doi.org/10.12669/pjms.36.5.3009

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Artificial intelligence in medical education: Are we ready for it?
Authors: Imran Nazish , Jawaid Masood
Published: June 2020

doi: https://doi.org/10.12669/pjms.36.5.3042

How to cite this:Imran N, Jawaid M. Artificial intelligence in medical education: Are we ready for it? Pak J Med Sci. 2020;36(5):857-859.  doi: https://doi.org/10.12669/pjms.36.5.3042

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Criminogenic Antecedents - Dynamics of Employee Criminal Behaviour in Business Organisations
Authors: Glebovskiy Alexander
Published: June 2020

Purpose: The purpose of this paper is to review the literature in terms of selected individual and organisational factors facilitating employee criminal behaviour in business organisations.
Approach: The paper draws on numerous theoretical perspectives on criminal behaviour in the business context, specifically crimes of obedience, moral disengagement, collective reasoning, groupthink, cost-benefit thinking, rationalisation, organisational culture, leadership, and ethical behaviour to explain arrange of criminogenic processes and factors that shape employee criminal behaviour in organisational settings.
Findings: Employee criminal behaviour in businesses is influenced by both organisational factors (organisational structure and culture, leadership, followership, ethical climate) and individual factors (self-regulatory capabilities, moral values, beliefs about leader-follower exchanges, narcissism, Machiavellianism, hubris). These elements interact to shape employee criminal behaviour and are subject to the influence of criminogenic processes such as displacement of responsibility, moral disengagement, rationalisation, groupthink and management by obedience. As a result of the criminalisation process, criminal behaviour is eventually normalised and institutionalized throughout a business organisation.
Practical implications: The paper helps business organisations understand the broad range of criminogenic factors and processes that influence criminal behaviour. This knowledge has important implications for the formulation and implementation of measures aimed at deterring this behaviour in business organisations.
Limitations: The scope of the organisational and individual-related factors under discussion which promote employee criminal behaviour in business organisations is not exhaustive. There are further criminogenic factors influencing employee criminal conduct, which are not covered by this review.
Originality/value: The paper discusses some criminogenic antecedents of employee criminal behaviour and analyses the source of this behaviour.
Assessment of liver function reserve by photoacoustic tomography: a feasibility study
Authors: Qiu Tingting , Yang Jinge , Pan Teng , Peng Chihan , Jiang Huabei , Luo Yan
Published: June 2020

Assessment of liver function reserve (LFR) is essential to determine
liver resection scope and predict prognosis for patients with liver
disease. Indocyanine green (ICG) concentration change is a classic
marker to reflect liver function reserve as ICG is selectively taken
up and eliminated by liver. Here we proposed a noninvasive approach
for LFR assessment based on a real-time photoacoustic tomography (PAT)
system. This feasibility study was to detect ICG concentration change
by PAT in phantom and in vivo using both normal and partial
hepatectomy (PH) rabbits. A linear relationship between photoacoustic
signal intensity of ICG and ICG concentration was found in vitro. In
vivo ICG concentration change over time after ICG injection was
observed by PAT in normal rabbits, which was consistent with the
findings measured by invasive spectrophotometry. Finally, clear
difference in ICG clearance between the control and PH models was
identified by PAT. Taken together, our study indicated the clinical
potential of PAT to in vivo evaluate LFR noninvasively.
Increasing the circular dichroism of the planar chiral nanostructure by inducing coupling between the coverage layer and the planar nanostructure
Authors: Bai Yu , Wang Tiankun , Ullah Hamad , Jing Zhimin , Abudukelimu Abuduwaili , Chen Chao , Qu Yu , Xu Hua , Zhu Dong , Zhang Zhongyue
Published: June 2020

Circular dichroism (CD) has been widely studied in recent decades because of its wide application in biomedical detection. Nanostructures with different heights (NDH) usually increase the transmission CD effect. To achieve such nanostructures, one needs to repeatedly perform the electron-beam lithography (EBL) method twice or more, layer-by-layer, which is a very complicated process. Here, we propose a method to prepare NDH by combining the EBL and oblique angle deposition (OAD) techniques. L-shaped planar silver nanostructures are prepared using EBL and normal electron beam deposition, and the OAD method is then used to partially cover one arm of the L-shaped nanostructure. Numerical simulations reveal that the height difference in the two arms of the L-shaped NDH (LSNDH) causes a difference in the polarization directions of the left- (LCP) and right-circularly polarized (RCP) incident light, thereby, generating CD effects. A 2D material is used to cover the LSNDH to further increase the charge polarization direction differences, which considerably increases the CD effect. These results are useful in simplifying and increasing the convenience of the preparation method of 3D chiral nanostructures. Furthermore, the proposed nanostructure may have potential application in biosensor, such as chiral enantiomer sensors.