bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting the Course of Graves’ Orbitopathy Using Serially Measured TSH-Receptor Autoantibodies by Automated Binding Immunoassays and the Functional Bioassay
Authors: Philipp Svenja , Eckstein Anja , Stöhr Mareile , Oeverhaus Michael , Lytton Simon D. , Horstmann Mareike , Zwanziger Denise , Möller Lars , Stark Achim , Führer-Sakel Dagmar , Bechrakis Nikolaos , Berchner-Pfannschmidt Utta , Banga J. Paul
Published: July 2021

The aim of the study was to investigate the use of serial measurements of TSH-receptor autoantibodies (TRAb) with the newest available assay technology to predict the course of Graves’ Orbitopathy (GO) during the first 24 months from disease onset. Serial serum samples from patients with GO (103 mild/135 severe) were collected between 2007 and 2017 and retrospectively analyzed. The course of GO were classified into mild/severe 12 months after manifestation (severe: NOSPECS≥5; mild<5). TRAb were measured with automated binding immunoassays (IU/l): TRAb Elecsys (Cobas, Roche), TRAb bridge assay (IMMULITE, Siemens), and a cell-based bioassay (percent of specimen to reference ratio - SRR%) (Thyretain, Quidel). Variable cut off levels of measured TRAb were calculated at specificity of 90% from receiver operator curve (ROC) analysis for several timepoints during the course of GO. To select one: 5–8 months after first GO symptoms, which is the timepoint for usual referals for treatment mild course could be predicted at cut offs of 1.5 IU/l (Elecsys), 0.8 IU/l (Immulite) and 402% SRR (Thyretain) and the risc of severe course has to be anticipated if TRAb are above 11.6 IU/l (Elecsys), 6.5 IU/l (Thyretain), and 714% SRR (Thyretain). The Thyretain bioassay showed the highest diagnostic sensitivity (using the commercial cut off’s) over the entire follow up period. TRAb measurements during the 24-month follow up of GO provide added value to the GO clinical activity and severity scores and should be used especially in the event of an unclear decision-taking situation with regard to therapy.
Magnets and a self-retractable wire for endoscopic septotomies: from concept to first-in-human use
Authors: Huberland François , Rio-Tinto Ricardo , Cauche Nicolas , Dugardeyn Sonia , Delattre Cécilia , Sandersen Charlotte , Rocq Laureen , van Ouytsel Pauline , Delchambre Alain , Devière Jacques , Blero Daniel
Published: July 2021

Background A medical device that allows simple and safe performance of an endoscopic septotomy could have several applications in the gastrointestinal (GI) tract. We have developed such a device by combining two magnets and a self-retractable wire to perform a progressive septotomy by compression of the tissues. We describe here the concept, preclinical studies, and first clinical use of the device for the treatment of symptomatic epiphrenic esophageal diverticulum (EED).

Methods The MAGUS (MAgnetic Gastrointestinal Universal Septotome) device was designed based on previous knowledge of compression anastomosis and currently unmet needs. After initial design, the feasibility of the technique was tested on artificial septa in pigs. A clinical trial was then initiated to assess the feasibility and safety of the technique.

Results Animal studies showed that the MAGUS can perform a complete septotomy at various levels of the GI tract. In two patients with a symptomatic EED, uneventful complete septotomy was observed within 28 and 39 days after the endoscopic procedure.

Conclusions This new system provides a way of performing endoluminal septotomy in a single procedure. It appears to be effective and safe for managing symptomatic EED. Further clinical applications where this type of remodeling of the GI tract could be beneficial are under investigation.
Chylous Ascites, Unusual Association with Ductal Pancreatic Adenocarcinoma with Plasmacytoid Morphology: A Case Report and Literature Review
Authors: Satala Catalin Bogdan , Jung Ioan , Bara Tivadar Jr. , Tudorache Vlad , Gurzu Simona
Published: July 2021

Chylous ascites represents a relatively uncommon condition. In this paper, we present a case of chyloperitoneum associated with pancreatic ductal adenocarcinoma (PDAC) and a review of literature regarding chylous ascites. A 76-year-old male patient was admitted in emergency department with acute abdomen. A pancreatic cancer was suspected. Subtotal spleno-pancreatectomy, for a nodular mass infiltrating the mild and distal portion of the pancreas, was necessary. During surgical intervention in the peritoneal cavity, a moderate quantity of whitish and thick consistency fluid with milk-like appearance was observed to be accumulated. After examination of the fluid, chyloperitoneum was diagnosed. The histologic examination showed a PDAC, with multiple emboli in lymph vessels, with tumor cells with plasmacytoid morphology, diagnosed as lymphangiosis carcinomatosa. The patient died at 3 weeks after surgical intervention. In patients with pancreatic cancer and chylous ascites, suspicion of tumor-related blockage of the lymphatic flow should be suspected. Prognosis of PDAC should be evaluated not only based on the number of lymph node metastases, but also considering the number of lymph vessels with tumor emboli and the architecture of tumor cells. This is the first reported case of a PDAC with plasmacytoid morphology of lymphangiosis carcinomatosa.
Large Bowel Obstruction
Authors: Johnson Wali R. , Hawkins Alexander T.
Published: July 2021

Nearly one-quarter of bowel obstructions occur in the large bowel. As with all bowel obstructions, large bowel obstructions have three defining characteristics: partial or complete, intrinsic or extrinsic, benign or malignant. The work-up for a large bowel obstruction should focus on the etiology of the obstruction as well as severity. Management strategy is contingent on the previous characteristics and can include endoscopy, diversion, or resection. This chapter will discuss common and rare etiologies of large bowel obstructions as well as management strategies for clinical guidance.
Lactoferrin Efficacy versus Ferrous Sulfate in Treatment of Children with Iron Deficiency Anemia
Authors: El-Asheer Osama Mahmoud , Ahmed Ahmed Gaber , Hafez Zainab AbdelAal Abdel , Dahpy Marwa AbdelHafiz , Soliman Amal AbdElSalam
Published: July 2021

Lactoferrin (LF) is an iron-binding globular glycoprotein that is structurally and chemically similar to serum transferrin. Many studies have been done to evaluate the effect of oral LF administration on iron deficiency anemia (IDA) with controversial results. This study was designed to compare the efficacy of LF versus oral ferrous sulfate (OFS) therapy in the treatment of children with IDA. A significant increase in mean hemoglobin and serum iron concentrations was noted in the group that received oral bovine LF (11.06 ± 0.96 and 42.79 ± 6.14, respectively) versus the group that received OFS (10.24 ± 0.57 and 28.94 ± 5.05, respectively, with p < 0.001 for each) after 30 days of the treatment with fewer side effects (9.3 vs. 33.3% with p = 0.043). Oral bovine LF is a more effective and safer alternative in treating iron deficiency and IDA compared with OFS with clinical benefits of fewer side effects and better patient compliance.
Gastric Neuroendocrine Tumor
Authors: Kargwal Naresh , Panda Viraj , Jha Abhijeet , Singh Chandra Bhushan
Published: July 2021

Gastric neuroendocrine tumor (gNET) is a rare carcinoid of the stomach whose incidence is increasing due to widespread use of upper gastrointestinal endoscopy (UGIE). There are four types of gNETs with different management strategies and prognosis. Here, we present a patient who came with abdomen pain and intermittent melena. UGIE showed a sessile polyp in the stomach. The patient subsequently underwent polypectomy and was symptomatically relieved.
Utility of Neonatal Findings in Early Diagnosis of a Case of Haberland Syndrome
Authors: Sturgis Morgan R. , Wrobel Kathryn E. , Bosco Gianna N. , Jones Carolyn H.
Published: July 2021

Haberland syndrome or encephalocraniocutaneous lipomatosis (ECCL) is a rare, congenital syndrome characterized by lipomas and noncancerous tumors of the scalp, skin, and eyes, in addition to intellectual disability, early onset seizures, and ectomesodermal dysgenesis. The diagnosis of ECCL is classically made by clinical presentation, imaging, and histopathological findings, but due to the spectrum of clinical presentation and symptom severity, diagnosis is often delayed until adolescence or adulthood. Here we present a newborn male infant, one of the earliest case diagnoses to our knowledge, with a unique constellation of physical exam and neuroimaging findings consistent with this diagnosis. We aim to address important neonatal findings to aid in early detection and diagnosis of this unique disease, which is thought to improve clinical outcomes and patient quality of life.
Predictors for Prolonged Drain Use Following Autologous Breast Reconstruction
Authors: Dinis Jacob , Allam Omar , Junn Alexandra , Park Kitae Eric , Mozaffari Mohammad Ali , Shah Rema , Avraham Tomer , Alperovich Michael
Published: July 2021

Background Surgical drains are routinely used following autologous reconstruction, but are often cited as the leading cause of peri-operative discomfort. This study defined routine drain use duration and assessed the risk factors for prolonged breast and abdominal drain use during microvascular breast reconstruction, measures which have never previously been defined.

Methods Patients who underwent an abdominal microvascular free flap were included. Demographics, comorbidities, and operation-related characteristics were retrospectively collected in a prospectively maintained database. Statistical analysis utilized chi-square independent t-test, and linear regression analyses.

Results One hundred forty-nine patients comprising 233 breast flaps were included. Average breast and abdominal drain duration were 12.9 ± 3.9 and 17.7 ± 8.2 days, respectively. Prolonged breast and abdominal drain duration were defined as drain use beyond the 75th percentile at 14 and 19 days, respectively. Multivariable regression revealed hypertension was associated with an increased breast drain duration by 1.4 days (p = 0.024), axillary dissection with 1.7 days (p = 0.026), African-American race with 3.1 days (p < 0.001), Hispanic race with 1.6 days (p = 0.029), return to the OR with 3.2 days (p = 0.004), and each point increase in BMI with 0.1 days (p = 0.028). For abdominal drains, each point increase in BMI was associated with an increased abdominal drain duration by 0.3 days (p = 0.011), infection with 14.4 days (p < 0.001), and return to the OR with 5.7 days (p = 0.007).

Conclusion Elevated BMI, hypertension, and axillary dissection increase risk for prolonged breast drain requirement in autologous reconstruction. African-American and Hispanic populations experience prolonged breast drain requirement after controlling for other factors, warranting further study.
The Association between Implementation of an Enhanced Recovery after Cesarean Pathway with Standardized Discharge Prescriptions and Opioid Use and Pain Experience after Cesarean Delivery
Authors: McCoy Jennifer A. , Gutman Sarah , Hamm Rebecca F. , Srinivas Sindhu K.
Published: July 2021

Objective This study was aimed to evaluate opioid use after cesarean delivery (CD) and to assess implementation of an enhanced recovery after CD (ERAS-CD) pathway and its association with inpatient and postdischarge pain control and opioid use.

Study Design We conducted a baseline survey of women who underwent CD from January to March 2017 at a single, urban academic hospital. Patients were called 5 to 8 days after discharge and asked about their pain and postdischarge opioid use. An ERAS-CD pathway was implemented as a quality improvement initiative, including use of nonopioid analgesia and standardization of opioid discharge prescriptions to ≤25 tablets of oxycodone of 5 mg. From November to January 2019, a postimplementation survey was conducted to assess the association between this initiative and patients' pain control and postoperative opioid use, both inpatient and postdischarge.

Results Data were obtained from 152 women preimplementation (PRE) and 137 women post-implementation (POST); complete survey data were obtained from 102 women PRE and 98 women POST. The median inpatient morphine milligram equivalents consumed per patient decreased significantly from 141 [range: 90–195] PRE to 114 [range: 45–168] POST (p = 0.002). On a 0- to 10-point scale, median patient-reported pain scores at discharge decreased significantly (PRE: 7 [range: 5–8] vs. POST 5 [range: 3–7], p < 0.001). The median number of pills consumed after discharge also decreased significantly (PRE: 25 [range: 16–30] vs. POST 17.5 [range: 4–25], p = 0.001). The number of pills consumed was significantly associated with number prescribed (p < 0.001). The median number of leftover pills and number of refills did not significantly differ between groups. Median patient-reported pain scores at the week after discharge were lower in the POST group (PRE: 4 [range: 2–6] vs. POST 3[range: 1–5], p = 0.03).

Conclusion Implementing an ERAS-CD pathway was associated with a significant decrease in inpatient and postdischarge opioid consumption while improving pain control. Our data suggest that even fewer pills could be prescribed for some patients.

Key Points
Assisted Reproductive Technology and Perinatal Mortality: Selected States (2006–2011)
Authors: Chang Jeani , Zhang Yujia , Boulet Sheree L. , Crawford Sara B. , Copeland Glenn E. , Bernson Dana , Kirby Russell S. , Kissin Dmitry M. , Barfield Wanda D. ,   for States Monitoring Assisted Reproductive Technology (SMART) Collaborative
Published: July 2021

Objective This study aimed to compare trends and characteristics of assisted reproductive technology (ART) and non-ART perinatal deaths and to evaluate the association of perinatal mortality and method of conception (ART vs. non-ART) among ART and non-ART deliveries in Florida, Massachusetts, and Michigan from 2006 to 2011.

Study Design Retrospective cohort study using linked ART surveillance and vital records data from Florida, Massachusetts, and Michigan.

Results During 2006 to 2011, a total of 570 ART-conceived perinatal deaths and 25,158 non-ART conceived perinatal deaths were identified from the participating states. Overall, ART perinatal mortality rates were lower than non-ART perinatal mortality rates for both singletons (7.0/1,000 births vs. 10.2/1,000 births) and multiples (22.8/1,000 births vs. 41.2/1,000 births). At <28 weeks of gestation, the risk of perinatal death among ART singletons was significantly lower than non-ART singletons (adjusted risk ratio [aRR] = 0.46, 95% confidence interval [CI]: 0.26–0.85). Similar results were observed among multiples at <28 weeks of gestation (aRR = 0.64, 95% CI: 0.45–0.89).

Conclusion Our findings suggest that ART use is associated with a decreased risk of perinatal deaths prior to 28 weeks of gestation, which may be explained by earlier detection and management of fetal and maternal conditions among ART-conceived pregnancies. These findings provide valuable information for health care providers, including infertility specialists, obstetricians, and pediatricians when counseling ART users on risk of treatment.

Key Points
The Effect of Social Determinants and Socioeconomic Status on Laparoscopic Roux-En-Y Gastric Bypass for Weight Loss: An Analysis of the National Inpatient Sample
Authors: Singh Supreet , Guerra Jarot J. , Lazar Paige , Merchant Aziz M.
Published: July 2021

Objective In the United States, Black and Hispanic patients have a higher prevalence of obesity than Whites (49.6 vs. 44.8 vs. 42.2%, respectively). Despite higher rates of obesity among minority populations, bariatric surgery is performed at higher obesity levels in minorities than in Whites. This study examines the effects of various socioeconomic factors such as race, payer type, and income on the likelihood of undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB) at class II versus class III obesity and their associated complications.

Materials and Methods National Inpatient Sample (NIS) from 2016 to 2017 was queried to identify patients at least 18 years of age with a concomitant diagnosis of class II or class III obesity who underwent LRYGB. We analyzed obesity level at the time of LRYGB (class II vs. class III), postoperative intestinal obstruction during the admission, and occurrence of any noninfectious complication related to the surgery as our main outcomes. A multivariate logistic regression model was utilized to assess the association between our outcomes and socioeconomic factors associated with the admission.

Results A total of 76,405 LRYGB operations were included. Out of this total, 83% (63,640) LRYGB operations were in class III obesity. Black patients had a lower rate (11.6%) of LRYGB procedures at class II obesity than White (17.6%) and Hispanic (18%) patients (p < 0.001). Medicare, Medicaid, and lower income quartiles also showed lower rates of operation at class II obesity (p < 0.001). Black patients were 29% (95% confidence interval [CI]: 0.61–0.83, p < 0.001) less likely than Whites to have a LRYGB procedure at class II obesity, they were 119% (95% CI: 1.17–4.11, p = 0.0014) more likely to suffer a postoperative intestinal obstruction, and they were 93% (95% CI: 1.31–2.84, p < 0.001) more likely to suffer a noninfectious complication.

Conclusion Socioeconomic disparities in the surgical management of severe obesity persist in the United States, especially for LRYGB. This study highlights multiple demographic factors that led to LRYGB at later obesity levels. Black patients were also more likely to be associated with postoperative complications during the admission. The determinants of health disparities in obese patients need to be examined further to reduce potential long-term morbidity and mortality in minorities. Further research is also required to identify the adverse effects of health disparities in patients with severe obesity and obesity-related comorbidities.
Identification of wind turbine clusters for effective real time yaw control optimization
Authors: Bernardoni Federico , Ciri Umberto , Rotea Mario A. , Leonardi Stefano
Published: July 2021

Control algorithms seeking to maximize wind plant power production may not require that all turbines communicate with each other for the purpose of coordinating an optimal control solution. In practice, an efficient and robust control solution may result by coordinating only turbines that are aerodynamically coupled through wake effects. The implementation of such control strategy would require information of which clusters of turbines are coupled in this way. As the wind changes direction, the clusters of coupled turbines may vary continuously within the array. Hence, in practical applications, the identification of these clusters has to be performed in real time in order to efficiently apply a coordinated control approach. Results from large eddy simulations of the flow over a wind farm array of 4 × 4 turbines are used to mimic Supervisory Control And Data Acquisition (SCADA) data needed for the cluster identification method and to evaluate the effectiveness of the yaw control applied to the identified clusters. Results show that our proposed method is effective in identifying turbine clusters, and that their optimization leads to a significant gain over the baseline. When the proposed method does not find clusters, the yaw optimization is ineffective in increasing the power of the array of turbines. This study provides a model-free method to select the turbines that should communicate with another to increase power production in real time. In addition, the analysis of the flow field provides general insights on the effect of the local induction, as well as of the wind farm blockage, on yaw optimization strategies.
Dynamical response of a rocking rigid block
Authors: Liu Y. , Páez Chávez J. , Brzeski P. , Perlikowski P.
Published: July 2021

This paper investigates the complex dynamical behavior of a rigid block structure under harmonic ground excitation, thereby mimicking, for instance, the oscillation of the system under seismic excitation or containers placed on a ship under periodic acting of sea waves. The equations of motion are derived, assuming a large frictional coefficient at the interface between the block and the ground, in such a way that sliding cannot occur. In addition, the mathematical model assumes a loss of kinetic energy when an impact with the ground takes place. The resulting mathematical model is then formulated and studied in the framework of impulsive dynamical systems. Its complex dynamical response is studied in detail using two different approaches, based on direct numerical integration and path-following techniques, where the latter is implemented via the continuation platform COCO (Dankowicz and Schilder). Our study reveals the presence of various dynamical phenomena, such as branching points, fold and period-doubling bifurcation of limit cycles, symmetric and asymmetric periodic responses, and chaotic motions. By using the basin stability method, we also investigate the properties of solutions and their ranges of existence in phase and parameter spaces. Moreover, the study considers ground excitation conditions leading to the overturning of the block structure and shows parameter regions wherein such behavior can be avoided.
The effects of multispecies Hohlraum walls on stimulated Brillouin scattering, Hohlraum dynamics, and beam propagation
Authors: Ralph J. E. , Kemp A. , Meezan N. B. , Berger R. L. , Strozzi D. , MacGowan B. J. , Landen O. , Lemos N. , Belyaev M. , Biener M. , Callahan D. A. , Chapman T. , Divol L. , Hinkel D. E. , Moody J. , Nikroo A. , Jones O. , Schiaffino S. , Stadermann M. , Michel P.
Published: July 2021

Experiments and simulations have been conducted to investigate the efficacy of Ta2O5-lined Hohlraum walls at reducing stimulated Brillouin backscattering (SBS) as well as any subsequent effects on the Hohlraum dynamics and capsule implosions in indirect drive experiments at the National Ignition Facility. Using a 1.1 MJ 400 TW, 351 nm, shaped laser pulse, we measure a 5× reduction in SBS power in the peak of the pulse from the wall on the outer 50° cone beams. The SBS spectrum indicates a reduction in the high-Z spectral signature when using multispecies wall materials. Detailed hydrodynamic simulations were performed using different heat conduction models with flux limiters. Additional simulations were performed on the plasma maps using the 3D parallel paraxial code pF3D to compare backscatter powers between the pure Au and Ta2O5-lined Hohlraums. Further analysis, using hydrodynamically equivalent plasmas, shows that the SBS reduction is clearly a result of the added ion Landau damping caused by the oxygen ions and not from differences in plasma conditions. The experimental and simulation results also show an increase in the wall plasma expansion when using the Ta2O5 liner leading to a 70% more oblate implosion.
Influence of gas environment on the dynamics of wetting transition of laser-textured stainless steel meshes
Authors: Kim V. V. , Yalishev V. S. , Khan S. A. , Iqbal M. , Boltaev G. S. , Ganeev R. A. , Alnaser A. S.
Published: July 2021

We analyze the role of surrounding gas and aging in ambient air in the wettability behavior of laser-processed stainless steel meshes. Laser texturing of meshes was carried out in the presence of different gases (N2, O2, CO2, Ar, and SF6) in ambient atmospheric air and under different vacuum conditions. The influence of each gas on the evolution of the wettability properties after aging in ambient air is analyzed. The effects of low-pressure and vacuum aging allowed transforming the initial superhydrophilic characteristics of the laser-structured meshes to an almost superhydrophobic state.
Biodiesel synthesis from waste cooking oil using heterogeneous acid catalyst: Statistical optimization using linear regression model
Authors: Gonçalves Matheus Arrais , Lourenço Mares Erica K. , Luz Patrícia Teresa Souza da , Zamian José Roberto , Filho Geraldo N. da Rocha , Castro Heizir Ferreira de , Conceição Leyvison Rafael Vieira da
Published: July 2021

In this study, a heterogeneous acid catalyst composed of 12-molybdophosphoric acid (H3PMo12O40.xH2O) anchored in titanium oxide (TiO2) was synthesized using the incipient-wetness method. The catalyst was characterized by acid–base titration method in order to determine surface acidity, thermogravimetric analysis, and x-ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscopy, and energy dispersion x-ray spectroscopy. The catalyst was applied in transesterification reactions for biodiesel production from the waste cooking oil following a central composite design of centered face 23 and a statistical model was developed in order to describe the behavior of the ester content as a function of the independent variables temperature, alcohol:oil molar ratio, and catalyst dosage. The statistical model (R2 = 0.8943) was validated and showed a relative error below 3% between the experimental and predicted values. By means of linear regression methods and response surface methodology, the conditions of biodiesel synthesis reaction were optimized and 94.5% conversion into esters was obtained at 190 °C, alcohol:oil molar ratio of 90:1, and catalyst dosage of 5 wt. %. The univariate study of the reaction time showed that the reaction processed in 4 h presented the highest conversion in terms of ester content in the biodiesel produced. The proposed catalyst showed good catalytic activity up to the fourth reaction cycle, indicating its good development and application prospectus.
Microparticle transport along a planar electrode array using moving dielectrophoresis
Authors: Zaman Mohammad Asif , Padhy Punnag , Ren Wei , Wu Mo , Hesselink Lambertus
Published: July 2021

We present a device that can achieve controlled transport of colloidal microparticles using an array of micro-electrodes. By exciting the micro-electrodes in regular sequence with an AC voltage, a time-varying moving dielectrophoretic force-field is created. This force propels colloidal microparticles along the electrode array. Using this method, we demonstrate bidirectional transport of polystyrene micro-spheres. Electromagnetic simulation of the device is performed, and the dielectrophoretic force profile around the electrode array is mapped. We develop a Brownian dynamics model of the trajectory of a particle under the influence of the time-varying force-field. Numerical and experimental results showing controlled particle transport are presented. The numerical model is found to be in good agreement with experimental data. The developed numerical framework can be useful in designing and modeling lab-on-a-chip devices that employ external non-contact forces for micro-/nanoparticle manipulation.
Toward highly efficient luminescence in graphene quantum dots for optoelectronic applications
Authors: Yoon Hyewon , Park Minsu , Kim Jungmo , Novak Travis G. , Lee Sukki , Jeon Seokwoo
Published: July 2021

Graphene quantum dots (GQDs) are promising luminescent materials for various light-emitting, biological, and energy applications due to their low toxicity compared to cadmium-based semiconductor quantum dots. The practical application and use of GQDs is driven by their luminescent characteristics. As such, a critical need exists to control and tailor the emission properties of these materials to suit the targeted optoelectronic applications. In this review, the fundamental properties, synthesis methods, and strategies for incorporating GQDs into optoelectronic devices are discussed. We present the fundamentals on luminescence mechanism of GQDs, including reflections on the defect-related properties (i.e., oxygen functional groups and odd-numbered carbon rings in the basal plane). We then offer new guidelines for the fabrication of GQDs aimed at increasing the luminescence efficiency. Finally, we introduce strategies for integrating GQDs into optoelectronic devices based on architectural design of the fundamental properties.
Assessing the value-added efficiency of wind power industry value chain using DEA-Malmquist models
Authors: Liu Jicheng , Li Yuanyuan , Yan Suli
Published: July 2021

After the rapid development of China's wind power industry, the lack of core technology and the mismatch between the expansion and development speed have become increasingly prominent. In order to correctly understand the current situation and problems, the whole research process is divided into the following four steps. The first step takes the profit rate of main business from 2017 to 2019 as sample variable to study the smile pattern of the wind power industry value chain. The second step takes the Principal Component Analysis as the research method, and the evaluation index system is constructed, so as to further analyze the value-added driving factors. The third step uses the Data Envelopment Analysis (DEA) and Malmquist model as evaluation methods, and the static and dynamic efficiencies of each value chain link are evaluated, respectively. In step four, the selected companies are effectively clustered with the Cluster Analysis. The results show that the value chain shows a gradual deepening smile, the overall value-added efficiency is not ideal, and there are specific problems in each link. This paper aims to provide reference for enterprises to make targeted improvement on the basis of analyzing the current situation. It also provides reference for the comparison and promotion of other countries.
Electron temperature fluctuations correlated with energy confinement degradation in the EAST Ohmic plasmas
Authors: Wang R. L. , Liu Y. , Zou X. L. , Zhao H. L. , Zhou T. F. , Zhou C. , Liu A. D. , Li Y. D. , Sun P. J. , Zhang T. , Liu H. Q.
Published: July 2021

In saturated Ohmic confinement regime of the experimental advanced superconducting tokamak, significant changes in the relative electron temperature fluctuations T̃e/T¯e, measured by a correlation electron cyclotron emission system, have been observed. It was found that T̃e/T¯e is strongly dependent on the normalized electron temperature and density gradient, R/LTe=R∇Te/Te and R/Lne=R∇ne/ne. T̃e/T¯e stay at a high level when R/LTe is within the range of 17−25 and R/Lne is within the range of 4−6. It has been also observed that the energy confinement degradation is correlated with the increase in electron temperature fluctuations. The linear stability analysis results show that the electron temperature fluctuations are mainly attributed to the ion temperature gradient modes.
Feedback-based wavefront shaping based on light intensity distribution for focusing light through scattering media
Authors: Tang Shiyun , Tan Wenjiang , Si Jinhai , Li Jing , Yang Yang , Hou Xun
Published: July 2021

Feedback-based wavefront shaping for focusing light through scattering media is an established method. In conventional feedback-based wavefront shaping, the incident light is divided into N input modes that are modulated by a spatial light modulator (SLM) using N segments, each of which has the same number and size of pixels. Here we propose light intensity-dependent feedback-based wavefront shaping using a genetic algorithm to achieve the desired wavefront shaping in less time and with fewer iterations than the conventional method. In our method, a phase mask is divided into several regions, each being allocated different phase modulation units according to the distribution of light intensity, with the pixels of the SLM being grouped non-uniformly to modulate the incident light. Compared with the conventional method, the experimental response time of our method using four subregions decreased by 15.6% and the enhancement factor increased by 30.4%.
New thermally stimulated emission spectrometer for the detection of ultra-shallow low-density traps
Authors: Islam M. M. , Bakr M. , Aboa J. N. , Selim F. A.
Published: July 2021

Electron/hole traps alter the optical and electrical properties of materials by creating additional recombination pathways, trapping or providing charge carriers and modifying exciton dynamics. Understanding the defect/trap dynamics is crucial to control the optoelectronic properties of materials, and measuring donor/acceptor ionization energy is critical in semiconductor research. Here, we developed a highly sensitive thermally stimulated emission (TSE) spectrometer for the low temperature regime of 9–325 K to detect and characterize shallow traps in bandgap materials with enhanced sensitivity. It provides a powerful characterization tool for a wide range of semiconductors and electronic and photonic materials. This technique is ideal where electrical methods cannot be used for donor/acceptor characterization as in powder, irregular shape and thickness, and high resistive samples. The performance of the spectrometer was tested on Ce doped Y3Al5O12 single crystals, and the measurements identified several shallow levels that cannot be detected with conventional methods. Then, its capabilities were further demonstrated by detecting a shallow level in Ga2O3, which is emerging as an exceptional semiconductor for high-power devices and optoelectronics. A sophisticated data analysis technique based on the three-point analysis (TPA) approach was applied to deconvolute the highly overlapped TSE signals. The developed ultra-low temperature spectrometer together with the TPA deconvolution method provides a unique tool for studying exciton dynamics in photonic materials and measuring donor/acceptor ionization energies and densities in luminescent semiconductors. It will advance material characterization and development for a wide range of applications including lasers, electronic and illumination devices, and detectors for medical diagnostic and nuclear applications.
Optimizing two-electron repulsion integral calculations with McMurchie–Davidson method on graphic processing unit
Authors: Tian Yingqi , Suo Bingbing , Ma Yingjin , Jin Zhong
Published: July 2021

In this article, several optimization methods of two-electron repulsion integral calculations on a graphic processing unit (GPU) are presented. These methods are based on the investigations of the method presented by McMurchie and Davidson (MD). A new Boys function evaluation method for the GPU calculation is introduced. The series summation, the error function, and the finite sum formula method are combined; thus, good performance on the GPU can be achieved. By taking some theoretical study of the McMurchie–Davidson recurrence relations, three major optimization approaches are derived from the deduction of the general term formula for the Hermite expansion coefficient. The three approaches contain a new form of the Hermite expansion coefficients with corresponding recurrence relations, which is more efficient for one-electron integrals and [ss|∗∗] or [∗∗|ss] type two-electron integrals. In addition, a simple yet efficient new recurrence formula for the coefficient evaluation is derived, which is more efficient both in float operations and memory operations than its original one. In average, the new recurrence relation can save 26% float operations and 37% memory operations. Finally, a common sub-expression elimination (CSE) method is implemented. This CSE method is directly generated from some equalities we discovered from the general term formula other than by computer algebra system software. This optimized method achieved up to 3.09 speedups compared to the original MD method on the GPU and up to 92.75 speedups compared to the GAMESS calculation on the central processing unit.
The vacuum ultraviolet absorption spectrum of norbornadiene: Vibrational analysis of the singlet and triplet valence states of norbornadiene by configuration interaction and density functional calculations
Authors: Palmer Michael H. , Hoffmann Søren Vrønning , Jones Nykola C. , Coreno Marcello , de Simone Monica , Grazioli Cesare , Aitken R. Alan
Published: July 2021

A synchrotron-based vacuum ultraviolet (VUV) absorption spectrum of norbornadiene (NBD) is reported, and the extensive vibrational structure obtained has been analyzed. The previously known 5b13s-Rydberg state has been reinterpreted by comparison with our recent high-resolution photoelectron spectral analysis of the X2B1 ionic state. Additional vibrational details in the region of this Rydberg state are observed in its VUV spectrum when compared with the photoelectron 2B1 ionic state; this is attributed to the underlying valence state structure in the VUV. Valence and Rydberg state energies have been obtained by configuration interaction and time-dependent density functional theoretical methods. Several low-lying singlet valence states, especially those that arise from ππ* excitations, conventionally termed NV1 to NV4, have been examined in detail. Their Franck–Condon (FC) and Herzberg–Teller (HT) profiles have been investigated and fitted to the VUV spectrum. Estimates of the experimental 00 band positions have been made from these fits. The anomaly of the observed UV absorption by the 1A2 state of NBD is attributed to HT effects. Generally, the HT components are less than 10% of the FC terms. The calculated 5b13s lowest Rydberg state also shows a low level of HT components. The observed electron impact spectra of NBD have been analyzed in detail in terms of triplet states.
Critical curves of a piecewise linear map
Authors: Roberts John A. G. , Saito Asaki , Vivaldi Franco
Published: July 2021

We study the parameter space of a family of planar maps, which are linear on each of the right and left half-planes. We consider the set of parameters for which every orbit recurs to the boundary between half-planes. These parameters consist of algebraic curves, determined by the symbolic dynamics of the itinerary that connects boundary points. We study the algebraic and geometrical properties of these curves, in relation to such a symbolic dynamics.
Air swirl effect on spray characteristics and droplet dispersion in a twin-jet crossflow airblast injector
Authors: Patil Shirin , Sahu Srikrishna
Published: July 2021

Spray characterization in a novel twin-jet airblast injector is reported in this paper with the focus on the study of the effect of injector air swirl on droplet characteristics and dispersion behavior. The operational principle of the injector is based on achieving atomization of two liquid jets, injected in a radially opposite direction from a central hub by high-speed annular swirling cross-stream flow of air. Liquid jet atomization within model atomizers and the resulting spray study have not gained much attention in spite of its practical importance, for example, in lean premixed prevaporized combustors. In the present work, droplet size and three-component velocity measurements are measured in the above injector using the phase Doppler particle analyzer technique. Air velocity without liquid injection is also obtained using the laser Doppler velocimetry technique. For given inlet air and liquid mass flow rates, experiments are conducted in the absence and presence of annular air swirl corresponding to swirl number, S = 0 and 0.74, respectively. The addition of air swirl is found to dramatically affect the spray topology and also the measured spray characteristics as the droplet size reduces significantly downstream of the injector exit, which is explained. Droplet dispersion is studied by evaluating droplet size velocity correlation and also droplet Stokes number. The results not only provide insight into the physics behind improved atomization due to air swirl, but also demonstrate the ability of the novel injector to achieve atomization quality and high spray dispersion over a wide operating range.
Exponential and Gaussian traps in nano-TiO2 and their function in kinetics of the electron transfer to O2
Authors: Liu Baoshun , Li Liuyang , Wu Zhizhou , Zhou Xuedong , Zhao Xiujian
Published: July 2021

A quasi-equilibrium (QE) theoretical model is proposed to fit the slow dispersive electron relaxation of nano-TiO2 that occurs through the transfer to O2. The electron relaxation is obtained from measurement of photoinduced absorptions. By including both the traps with exponential and Gaussian distributions with respect to the energy, the electron relaxation is fully fitted with the QE model. A Monte Carlo simulation is also realized to fit the electron relaxation, which agrees well with the QE model. It is revealed that the kinetics of the electron transfer from TiO2 to O2 contains both contributions from the exponential and Gaussian traps. Their distributions are obtained from the QE model fitting. The dispersion factor of the exponential traps is ∼0.65 and the trap density is high. The Gaussian traps locate ∼0.4 eV below the conduction band and have narrow distribution. The density of the Gaussian traps is more than three orders of magnitude lower than that of the exponential traps. Despite the low density, the Gaussian traps have an important effect on the electron relaxation. The distributions of the thermal barriers for the electron relaxation are obtained for both relaxations contributed by the exponential and Gaussian traps, based on which the kinetics equations are proposed. The Gaussian trap contributed relaxation accords with mono-exponential kinetics, while the relaxation contributed from the exponential traps involves exponentially distributed weights. The apparent activation energy, kinetic time constants, and pre-exponential factor can be obtained.
Photocatalysis over MXene-based hybrids: Synthesis, surface chemistry, and interfacial charge kinetics
Authors: Peng Chao , Zhou Tao , Wei Ping , Xu Wenkang , Pan Hui , Peng Feng , Jia Jianbo , Zhang Kun , Yu Hao
Published: July 2021

Two-dimensional (2D) transition metal carbides and/or nitrides (MXenes) are a family of graphene-like 2D materials, with unique layered structures, high mechanical strength, excellent carrier mobility, and outstanding physical and chemical properties. In particular, the work function (Φ) of MXenes and Gibbs free energy of the adsorbed intermediate, such as H* (|△GH*|), can be regulated by their surface adsorption groups (–OH, –O, and –F), enabling the applications in the field of photocatalysis. This article systematically summarizes the recent advances of synthetic routes of MXene-based photocatalysts and discusses the interfacial charge kinetics and photogenerated charge transfer mechanism of MXene-based photocatalysts. Furthermore, major challenges and further research trends of MXene-based photocatalysts are also presented.
Synthetic frequency dimensions in dynamically modulated ring resonators
Authors: Yuan Luqi , Dutt Avik , Fan Shanhui
Published: July 2021

The concept of synthetic dimensions in photonics has attracted rapidly growing interest in the past few years. Among a variety of photonic systems, the ring resonator system under dynamic modulation has been investigated in depth both in theory and experiment and has proven to be a powerful way to build synthetic frequency dimensions. In this Tutorial, we start with a pedagogical introduction to the theoretical approaches in describing the dynamically modulated ring resonator system and then review experimental methods in building such a system. Moreover, we discuss important physical phenomena in synthetic dimensions, including nontrivial topological physics. This Tutorial provides a pathway toward studying the dynamically modulated ring resonator system and understanding synthetic dimensions in photonics and discusses future prospects for both fundamental research and practical applications using synthetic dimensions.
The role of etching anisotropy in the fabrication of freestanding oxide microstructures on SrTiO3(100), SrTiO3(110), and SrTiO3(111) substrates
Authors: Plaza Alejandro Enrique , Manca Nicola , Bernini Cristina , Marré Daniele , Pellegrino Luca
Published: July 2021

The release process for the fabrication of freestanding oxide microstructures relies on appropriate, controllable, and repeatable wet etching procedures. SrTiO3 (STO) is among the most employed substrates for oxide thin films growth and can be decomposed in HF:water solution. Such a process is strongly anisotropic and is affected by local defects and substrate cut-planes. We analyze the etching behavior of SrTiO3 substrates having (100), (110), and (111) cut-planes during immersion in a 5% HF:water solution. The etching process over the three substrates is compared in terms of pitting, anisotropy, macroscopic etch rate, and underetching effects around HF-resistant (La,Sr)MnO3 thin film micropatterns. The release of targeted structures, such as the reported (La,Sr)MnO3 freestanding microbridges, depends on the substrate crystallographic symmetry and on the in-plane orientation of the structures themselves along the planar directions. By comparing the etching evolution at two different length scales, we distinguish two regimes for the propagation of the etching front: an intrinsic one, owing to a specific lattice direction, and a macroscopic one, resulting from the mixing of different etching fronts. We report the morphologies of the etched SrTiO3 surfaces and the geometries of the underetched regions as well as of the microbridge clamping zones. The reported analysis will enable the design of complex MEMS devices by allowing to model the evolution of the etching process required for the release of arbitrary structures made of oxide thin films deposited on top of STO.
Stability of an oscillatory Taylor–Couette flow in an upper convected Maxwell fluid
Authors: Hayani Choujaa Mohamed , Aniss Saïd , Ouazzani Touhami Mohamed , Khalid Naciri Jâafar , Riahi Mehdi
Published: July 2021

The stability of pulsed bi-dimensional flow between two co-oscillating cylinders in a linear Maxwell fluid was studied by Riahi et al. [J. Soc. Rheol. 42, 321–327 (2014)]. In the present paper, we revisit this flow configuration with emphasis on the effect of the non-linear terms in the constitutive equation of the model, measured by the Weissenberg number, on the dynamics of the system. Under these assumptions and using the upper convected Maxwell derivative, we examine this model to large amplitude oscillatory shear giving rise to the appearance, in comparison to the linear Maxwell model, of the azimuthal normal stress in the basic state. Using the spectral method and the Floquet theory for the spatiotemporal resolution of the obtained eigenvalue problem, numerical results exhibit numerous classes of Taylor vortex flows depending on the order of magnitude of the fluid elasticity. The resulting stability diagram consists of several branches intersecting at specific frequencies where two different Taylor vortex flows simultaneously branch off from the basic state. This feature is accompanied by the occurrence of several co-dimension two bifurcation points besides jumps/drops in the corresponding critical wave number. In addition, it turns out that the elasticity produces strong destabilizing and stabilizing effects in the limit of high and low frequency regimes, respectively, attributed solely to the non-linearities considered by the rheological model.
Nanoscale morphology of thin liquid films near the advancing contact line during condensation
Authors: Mehrizi Abbasali Abouei , Liu Qiao , Wang Hao
Published: July 2021

The extended thin-film region adjacent to the contact line is crucial in heat transfer because of its capability to enhance heat transfer and its critical role in wetting dynamics. The present investigation focused on the study of advancing contact line morphology induced by water vapor condensation. The condensation was at low rates with the advancing velocities <60 nm/s. Two modes of atomic force microscopy were utilized to measure the morphology of a liquid film with the nanometer resolution. The results indicated that the profile of the film went straight down to the apparent contact line when viewed in a sub-micron window, which is in contrast to nonvolatile cases, such as glycerol and silicon oil, which would have a convex nanobending around 20 nm from the substrate surface due to the local dynamic friction. Furthermore, a precursor nanofilm was detected beyond the contact line during condensation, and nanodroplets hundreds of nanometers in height were sitting on the nanofilm, representing the structure of the advancing contact line, and being adjacent to the condensation plays an essential role in contact line dynamics.