bluuebunny/crossref_metadata_2025 huggingface dataset:
Preoperative and Postoperative Opioid Dependence in Patients Undergoing Anterior Cervical Diskectomy and Fusion for Degenerative Spinal Disorders
Authors: Dietz Nicholas , Sharma Mayur , Alhourani Ahmad , Ugiliweneza Beatrice , Nuno Miriam , Drazin Doniel , Wang Dengzhi , Boakye Maxwell
Published: February 2021

Background Anterior cervical diskectomy and fusion (ACDF) is a procedure for effectively relieving radiculopathy. Opioids are commonly overprescribed in postsurgical settings and prescriptions vary widely among providers. We identify trends in opioid dependence before and after ACDF.

Methods We used the Truven Health MarketScan data to identify adult patients undergoing ACDF for degenerative cervical spine conditions between 2009 and 2015. Patients were segregated in four cohorts of preoperative and postoperative opioid nondependence (ND) or dependence (D) with 15 months of postoperative follow-up.

Results A total of 25,403 patients with median age of 52 years (18–92) who underwent ACDF met the inclusion criteria. Breakdown of the four cohorts was as follows: prior nondependent who remain nondependent (NDND): 62.76% (n = 15,944); prior nondependent who become dependent (NDD): 4.6% (n = 1,168); prior dependent who become nondependent (DND): 14.03% (n = 3,564); and prior dependent who remain dependent (DD): 18.61% (n = 4,727). Opioid dependence decreased 9.43% postoperatively. Overall payments and 30-day readmissions increased 1.96 and 1.79 times for opioid dependent versus nondependent cohorts, respectively. Adjusted payments at 3 to 15 months were significantly increased for dependent cohorts with 3.56-fold increase for the DD cohort when compared with the NDND cohort. Length of stay, complications, medication refills, outpatient measures, and hospital admissions were also higher in those groups with postoperative opioid dependence when compared with those who were not opioid dependent.

Conclusions Opioid dependence after ACDF is associated with increased hospital readmissions, complication rates at 30 days, and payments within 3 months and 3 to 15 months postdischarge. Overall opioid dependence was decreased after ACDF procedure, however, a smaller number of opioid-dependent and opioid-naive patients became dependent postoperatively and should be followed carefully.
Outcome Features Analysis in Intramedullary Tumors of the Cervicomedullary Junction: A Surgical Series
Authors: Brunetto Giacoma Maria Floriana , Tariciotti Leonardo , Landi Alessandro , Gregori Fabrizio , Santoro Francesca , Frati Alessandro , Delfini Roberto , Santoro Antonio
Published: February 2021

Object The aim of this study is to investigate the impact of surgery for different cervicomedullary lesions on symptomatic pattern expression and postoperative outcome. We focused on specific outcome features of the early and late postoperative assessments. The former relies on surgery-related transient and permanent morbidity and feasibility of radicality in eloquent areas, whereas the latter on long-term course in lower grade tumors and benign tumorlike lesions (cavernomas, etc.).

Material and Methods We retrospectively analyzed 28 cases of intramedullary tumors of the cervicomedullary junction surgically treated at our institution between 1990 and 2018. All cases were stratified for gender, histology, macroscopic appearance, location, surgical approach, and presence of a plane of dissection (POD). Mean follow-up was 5.6 years and it was performed via periodic magnetic resonance imaging (MRI) and functional assessments (Karnofsky Performance Scale [KPS] and modified McCormick [MC] grading system).

Results In all, 78.5% were low-grade tumors (or benign lesions) and 21.5% were high-grade tumors. Sixty-one percent underwent median suboccipital approach, 18% a posterolateral approach, and 21% a posterior cervical approach. Gross total resection was achieved in 54% of cases, near-total resection (>90%) in 14%, and subtotal resection (50–90%) in 32% of cases. Early postoperative morbidity was 25%, but late functional evaluation in 79% of the patients showed KPS > 70 and MC grade I; only 21% of cases showed KPS < 70 and MC grades II and III at late follow-up. Mean overall survival was 7 years in low-grade tumors or cavernomas and 11.7 months in high-grade tumors. Progression-free survival at the end of follow-up was 71% (evaluated mainly on low-grade tumors).

Conclusions The surgical goal should be to achieve maximal cytoreduction and minimal postoperative neurologic damage. Functional outcome is influenced by the presence of a POD, radicality, histology, preoperative status, and employment of advanced neuroimaging planning and intraoperative monitoring.
Surgical Procedure in the Treatment of Organized Chronic Subdural Hematoma: A Single-Center Experience
Authors: Chen Keng , Wang Kun , Chen Danzhi , Niu Huanjiang , Yang Shuxu , Wang Yirong
Published: February 2021

Background Organized chronic subdural hematoma (CSDH) is a special type of CSDH. However, the optimal surgical procedure has not been established. We present our experience here to discuss the surgical procedure in treatment of organized CSDH.

Methods Thirty-three patients with organized CSDH were admitted between January 1, 2008 and January 1, 2018. Age, gender, clinical symptoms, imaging data, type of surgical procedure, Barthel index (BI), and postoperative complications were collected and retrospectively analyzed. The BI was assessed both pre and postoperatively (1 week and 1 month after surgery).

Results Overall, 14 patients underwent large craniotomy and 19 patients underwent small craniotomy. No significant differences in gender, age, initial clinical symptoms, and preoperative BI were found between the groups (p > 0.05). Among the 14 patients who underwent large craniotomy, 2 patients developed epilepsy after the operation, while 1 patient had postoperative aphasia. None of the patients had recurrence in 6 months postoperatively. Among the 19 patients who underwent small craniotomy, 1 patient developed an acute subdural hematoma and 1 patient developed aphasia. No obvious complications were found in the remaining 18 patients and none of the 19 patients had recurrence in 6 months postoperatively. BI scores of the small craniotomy group were significantly better than those of the large craniotomy group at 1 week postoperatively (p < 0.05). However, there was no significant difference in the 1-month results (p > 0.05).

Conclusion According to our single-center experience, a small craniotomy for treating organized CSDH can be considered as an alternative to a larger craniotomy.
Comparación entre las secuencias axiales densidad de protones y T2 en lesiones medulares cervicales de pacientes con esclerosis múltiple
Authors: Herazo-Bustos Cherina , Tramontini Jens Carolina , Mora Salazar Juan Andrés , Taborda Karen Nieto , Navas Carlos
Published: February 2021

Introducción Las secuencias ponderaras en T2 con tiempo de eco largo son tradicionalmente usadas para la evaluación de las lesiones de la médula espinal en esclerosis múltiple (EM). Existen otras secuencias, como la densidad de protones (primer eco T2), que pueden ser útiles en el plano axial pero que no se han estudiado lo suficiente.

Objetivos Establecer la concordancia entre la densidad de protones (DP) y las secuencias axiales ponderadas en T2 en las lesiones de la médula espinal cervical en pacientes con EM.

Métodos Se trata de un estudio de concordancia entre secuencias DP y T2 axiales en magneto de 1,5 Tesla en sujetos colombianos. Las imágenes fueron revisadas por dos radiólogos, que determinaron el número de lesiones, así como la intensidad de señal —mediante la relación contraste— ruido (RCR). La comparación se realizó con el coeficiente de correlación y concordancia de Lin.

Resultados Se evaluaron 56 pacientes, 30,36% hombres y 69,64% mujeres. Se encontraron diferentes números de lesiones entre las secuencias axiales DP vs T2 (210 vs 144), coeficiente de concordancia entre el número de lesiones 0,72 (IC95%: 0,6–0,82, error estándar 0,05, desviación estándar 1,37) y en la conspicuidad —RCR— 0,62 (IC95%: 0,48–0,75, SE 0,05, DE 12,25).

Conclusión No encontramos concordancia en la evaluación del número o intensidad de la señal entre secuencias axiales DP y T2. Aunque las secuencias ponderadas en T2 son las más utilizadas, investigaciones recientes han demostrado falta de concordancia e incluso superioridad de las secuencias DP en otros planos, lo que sugiere que es necesario realizar estudios para evaluar la efectividad de las secuencias DP en el plano axial.
Video-Assisted Thoracoscopic Segmentectomy for Deep and Peripheral Small Lung Cancer
Authors: Takamori Satoshi , Oizumi Hiroyuki , Suzuki Jun , Suzuki Katsuyuki , Kabasawa Takanobu
Published: February 2021

Background We aimed to retrospectively compare the long-term prognosis and recurrence after segmentectomy between nonsmall cell lung cancer (NSCLC) patients with deep and peripheral lesions.

Methods Data were extracted for 85 lobectomy-tolerable NSCLC patients with tumors measuring ≤2 cm, who underwent video-assisted thoracoscopic segmentectomy with curative intent during January 2006 to December 2014. Tumor location was determined by the surgeon using thin-slice (1 mm) and three-dimensional computed tomography. Overall and recurrence-free survival was compared between patients with peripheral and deep lesions using univariate and multivariate Cox proportional hazard models. The indications for segmentectomy included NSCLC measuring ≤2 cm and consolidation/tumor ratio ≤20%, solid NSCLC ≤1 cm, and indeterminate nodule ≤1.5 cm.

Results No recurrence of peripheral and deep lesions was noted. The 5-year overall survival was 96.4% for all patients, and 100 and 95.3% for patients with deep and peripheral lesions, respectively. There was no significant difference between the overall survival rates associated with the deep and peripheral lesions (95% confidence interval [CI], 89.5–98.8, nonsignificant, 86.4–98.4, respectively; p = 0.189). In a multivariate analysis, the American Society of Anesthesiologists score (hazard ratio [HR], 13.30; 95% CI, 1.31–210.36; p = 0.028) and histology (HR, 0.03; 95% CI, 0.00–0.32; p = 0.037) were independent prognostic factors for overall survival; tumor location was not a prognostic factor.

Conclusions When video-assisted thoracoscopic segmentectomy with curative intent was performed with sufficient surgical margins, the location of small NSCLC did not affect recurrence risk and prognosis. Video-assisted thoracoscopic segmentectomy for small NSCLC is acceptable, regardless of the tumor location.
Transoral Endoscopic Localization of the Parapharyngeal Internal Carotid Artery
Authors: Zhang Guoliang , Zhao Xia , Sun Guangbin , Gao Nan , Yu Pengcheng , Chen Zhongchun
Published: February 2021

Objectives To define transoral endoscopic surgical landmarks for the parapharyngeal segment of the internal carotid artery (ppICA) using cadaveric dissection.

Methods Ten fresh cadaveric heads were dissected to demonstrate the parapharyngeal space anatomy and course of the ppICA as seen in a transoral approach. Anatomical measurements of the distance between the ppICA and bony landmarks were recorded and analyzed.

Results The stylohyoid ligament, styloglossus, and stylopharyngeus could be considered to be the safe anterior boundary of the ppICA in the transoral approach; among them, the styloid ligament was the most rigid tissue. Dissection between the stylopharyngeus muscle and superior pharyngeal constrictor muscle provides direct access to the ppICA. At the level of the skull base, the distance from the root of the styloid process to the lateral margin of the external aperture of the carotid canal on the left side and on the right side was 8.57 ± 1.97 and 8.80 ± 1.21 mm, respectively. At the level of the maxillary tuberosity, the distance from the ppICA to the maxillary tuberosity on the left side and on the right side was 31.48 ± 2.24 and 31.01 ± 2.88 mm, respectively.

Conclusion The endoscopic-assisted transoral approach can facilitate exposure of the ppICA. The root of the styloid process, styloid ligament, and maxillary tuberosity are critical landmarks in the identification of the ppICA in the transoral approach.
Antibiotic Use in Lateral Skull Base Surgery: A Survey of the North American Skull Base Society
Authors: Li Kevin L. , Fang Christina H. , Hawn Vivian S. , Agarwal Vijay , Kshettry Varun R. , Bellile Emily , Akbar Nadeem A. , McKean Erin L. , Abuzeid Waleed M. , Moskowitz Howard S.
Published: February 2021

Objectives Antibiotic use in lateral skull base surgery (LSBS) has not been thoroughly investigated in the literature. There is wide variability in antibiotic use and insufficient data to guide management. This study aims to describe the factors and patterns influencing antibiotic use in LSBS among the membership of the North American Skull Base Society (NASBS).

Design An online-based survey was designed and distributed to the membership of the NASBS. Data was analyzed using bivariate analysis and logistic regression modeling.

Setting Online-based questionnaire.

Participants NASBS membership.

Main Outcome Measures Use of intraoperative antibiotics and use of postoperative antibiotics.

Results The survey response rate was 26% (208 respondents). Of the 208 total respondents, 143 (69%) respondents performed LSBS. Most respondents are neurosurgeons (69%) with the remaining being otolaryngologists (31%). The majority of respondents (79%) are fellowship-trained in skull base surgery. Academic or government physicians make up 69% of respondents and 31% are in private practice with or without academic affiliations. Bivariate analysis showed that practice setting significantly influenced intraoperative antibiotic use (p = 0.01). Geographic location significantly affected postoperative antibiotic use (p = 0.01). Postoperative antibiotic duration was significantly affected by presence of chronic otitis media, cerebrospinal fluid leak, and surgeon training (p = 0.02, p = 0.01, and p = 0.006, respectively). Logistic regression modeling showed that the motivation to reduce infection significantly impacted postoperative antibiotic use (p = 0.03).

Conclusion This study demonstrates significant variations in intraoperative and postoperative antibiotic use in LSBS among the NASBS membership. Appropriate guidelines for optimal perioperative antibiotic use patterns should be determined with randomized studies in the future.
Hybrid acousto-elastic metamaterials for simultaneous control of low-frequency sound and vibration
Authors: Chen Chuanmin , Guo Zhaofeng , Liu Songtao , Feng Hongda , Qiao Chuanxi
Published: February 2021

Metamaterials have shown great potential for controlling acoustic waves and structural dynamics. Although various types of metamaterials have been developed, simultaneous control of low-frequency sound in air and vibration in solids is less investigated. This paper presents hybrid acousto-elastic metamaterials that enable simultaneous control of low-frequency sound in air and vibration in solids. For the first time, this novel metamaterial adds a compound of membrane and silicone rubber to cladding. The membrane moves the resonance frequency to a low frequency, and the silicone rubber makes the cladding layer rigid enough to support the mass. Bandgap, sound transmission loss (STL), and vibration transmission loss (VTL) were calculated by using the finite element method. Combining modal vibration mode and sound intensity streamline, the mechanisms of vibration isolation and noise reduction were analyzed and then verified through the equivalent mass–spring model. This novel metamaterial combines acoustic metamaterials and mechanical metamaterials to achieve the collaborative control of elastic waves and acoustic waves. At the same time, the peak frequencies of both STL and VTL are lower than those of the traditional metamaterials of the same size, which provides a theoretical basis and method guidance for the next step of collaborative control research of mechanical metamaterials and acoustic metamaterials. It has potential application value in the field of low-frequency vibration and noise control engineering.
Heterogeneously structured phase-change materials and memory
Authors: Yang Wonjun , Hur Namwook , Lim Dong-Hyeok , Jeong Hongsik , Suh Joonki
Published: February 2021

Phase-change memory (PCM), a non-volatile memory technology, is considered the most promising candidate for storage class memory and neuro-inspired devices. It is generally fabricated based on GeTe–Sb2Te3 pseudo-binary alloys. However, natively, it has technical limitations, such as noise and drift in electrical resistance and high current in operation for real-world device applications. Recently, heterogeneously structured PCMs (HET-PCMs), where phase-change materials are hetero-assembled with functional (barrier) materials in a memory cell, have shown a dramatic enhancement in device performance by reducing such inherent limitations. In this Perspective, we introduce recent developments in HET-PCMs and relevant mechanisms of operation in comparison with those of conventional alloy-type PCMs. We also highlight corresponding device enhancements, particularly their thermal stability, endurance, RESET current density, SET speed, and resistance drift. Last, we provide an outlook on promising research directions for HET-PCMs including PCM-based neuromorphic computing.
An adaptive instinctive reaction strategy based on Harris hawks optimization algorithm for numerical optimization problems
Authors: Yuan Yongliang , Ren Jianji , Zu Jinxue , Mu Xiaokai
Published: February 2021

An adaptive Harris hawks optimization (HHO) algorithm is proposed to solve the non-linearly constrained optimization problems. The algorithm, namely, instinctive reaction strategy based on HHO (IRSHHO), combines the instinctive reaction strategy (IRS) with the HHO algorithm. In IRSHHO, the increment of step length decreases with the increase in the iteration. Moreover, the energy of the prey is also considered to speed up the convergence in each iteration. The performance of the IRSHHO is investigated on five benchmark numerical examples. The results of IRSHHO provide very competitive results compared to other well-known algorithms. Furthermore, the IRSHHO is applied to optimize the auto drum fashioned brake problem. Results show that the IRSHHO can obtain the optimal solution with the braking efficiency factor that is increased by 27.872% from the initial design with the proposed IRSHHO method.
Room-temperature active modulation of plasmonic nanolasers by current injection on hybrid graphene–insulator–metal platforms
Authors: Li Heng , Huang Zhen-Ting , Hong Kuo-Bin , Chen Jia-Wei , Cheng Chang-Wei , Chen Kuo-Ping , Lin Tzy-Rong , Gwo Shang-jr , Lu Tien-Chang
Published: February 2021

The room-temperature active modulation of plasmonic nanolasers is demonstrated on the hybrid graphene–insulator–metal (GIM) platform. The threshold and lasing intensity of ZnO plasmonic nanolasers are modulated by injecting the current into the graphene layer in order to break the Lorentz reciprocity in the plasmonic cavity. The laser threshold increases with the external current injection, and a 0.17-nm Doppler shift is observed with 120-mA external current injection. The theoretical model is constructed that takes both the nonreciprocal effect and thermal effect induced by the current injection into consideration. The nanolaser operated at room temperature and with the functionality of threshold modulation on the GIM platform shall be very promising in the development of integrated photonic circuits.
From the dipole of a crystallite to the polarization of a crystal
Authors: Resta Raffaele
Published: February 2021

The quantum-mechanical expression for the polarization of a crystalline solid does not bear any resemblance to the (trivial) expression for the dipole of a bounded crystallite; in fact, it has been proved via a conceptually different path. Here, I show how to alternatively define the dipole of a bounded sample in a somewhat unconventional way; from such a formula, the crystalline polarization formula—as routinely implemented in electronic-structure codes—follows almost seamlessly.
Inequalities in the utilisation of the Child Dental Benefits Schedule between Aboriginal
Authors: Orr Neil , Gwynne Kylie , Sohn Woosung , Skinner John
Published: February 2021

Objectives The Child Dental Benefits Schedule (CDBS) is an Australian Government initiative providing basic dental care to children from low-income households. We sought to investigate levels of utilisation of the CDBS among Aboriginal and non-Aboriginal children to determine whether there is equal access to dental services provided through the schedule. Methods CDBS data were obtained for four financial (July–June) years (from 2013–14 to 2016–17). The data captured all claims made during this period. The data included estimates of usage by Aboriginal status, age group and Dental Benefits groups (administrative categories of related dental procedures). Results The utilisation of CDBS services was lower for Aboriginal children. However, in 2013–14, although the odds of using the schedule were higher for non-Aboriginal children (odds ratio (OR) 0.89; P < 0.0001) this was reversed in 2015–16 and 2016–17 (OR 1.11 and 1.21 respectively; P < 0.0001 in both years). The odds of Aboriginal children using preventive services was below that of non-Aboriginal children in 2013–14 (OR 0.82), 2014–15 (OR 0.76), 2015–16 (OR 0.83) and 2016–17 (OR 0.90; P < 0.0001) in all years. Conclusions The data are encouraging with regard to equity because they show that for services overall, Australian Aboriginal and non-Aboriginal children have similar levels of utilisation. However, lower levels of the use of preventive services may indicate future inequalities in oral health among Aboriginal children. What is known about the topic? The CDBS is an Australian Government initiative aimed at improving access to dental care for children from low-income households, including for Aboriginal people. By facilitating greater access to dental care, the schedule has the potential to help address inequalities in oral health for both Aboriginal and non-Aboriginal children. What does this paper add? There are no analyses available comparing the utilisation of the CDBS by Aboriginal and non-Aboriginal children. This study compared levels of utilisation of the schedule overall and specifically for preventive services. What are the implications for practitioners? Greater efforts should be made to address inequalities in the utilisation of the CDBS between Aboriginal and non-Aboriginal children. Although there are some hopeful signs, inequalities remain that may affect the oral health of Aboriginal children. There is also potential to encourage utilisation of the CDBS for greater provision of preventive services, including targeted population oral health initiatives.
Students for Freedom and Equality: The Inevitable Return of the Left in Post-Revolutionary Iran
Authors: Vahabzadeh Peyman
Published: February 2021

The emergence and rapid but short-lived presence of Students for Freedom and Equality (SFE; in Persian: Daneshjuyan-e Azadikhah va Barabaritalab or DAB) across major Iranian campuses and their fateful 4 December 2007 protest rally on the campus of the University of Tehran speaks of the return of leftist student activism to Iranian campuses after almost two decades of absence or invisibility within the context of post-revolutionary Iran. SFE was an umbrella democratic organization: its activists came from a plurality of social and political backgrounds and adhered to diverse leftist ideas. But in the context of pro-Reform Movement student activism in Iranian post-secondary institutions in the late 1990s and in 2000s, for a short time the SFE tried to hegemonize student activism and challenge the various pro-government tendencies in university campuses. Before state repression forced the SFE out of operation in 2007, Students for Freedom and Equality brought to campuses candid discussions of social justice issues, critique of Iran’s neoliberal economic policies, and challenges to censorship and lack of freedom.
Ferromagnetic ordering in a THAB exfoliated WS2 nanosheet
Authors: Debnath Anup , Shaw Bikash Kumar , Bhattacharya Shatabda , Saha Shyamal K
Published: February 2021

Because of the important role of two-dimensional (2D) magnetic semiconductors in low-dimensional spintronic devices, the generation of ferromagnetism within an ultrathin semiconducting sheet of a transition metal dichalcogenide is highly desirable. A pristine WS2 sheet is a diamagnetic semiconducting transition metal dichalcogenide with superior electronic properties. In this study, we synthesised a free-standing WS2 sheet by a chemical route followed by electrochemical exfoliation by a giant molecule. During exfoliation of the WS2 crystal, atomic vacancies were created in the sheet with a lower number of layers. To understand the mechanism of exfoliation, we carried out x-ray diffraction, transmission electron microscopy, atomic force microscopy and Raman measurements. The types of atomic vacancies were realised by energy-dispersive x-ray spectroscopy, high-resolution transmission electron microscopy (fast Fourier transform), and x-ray photoelectron spectroscopy studies. We also observed a ferromagnetic ordering within the exfoliated WS2 sheet, which is explained on the basis of the generation of an atomic vacancy induced spin-moment. The transport study of the exfoliated WS2 sheet suggests that the electro-transport behaviour still remains as a semiconductor even after exfoliation. This ferromagnetic semiconducting system will be applicable in spintronic devices and this technique will enrich the literature, particularly for the preparation of a 2D semiconducting ferromagnet in a facile fashion.
Strain glass versus antisite disorder induced ferromagnetic state in Fe doped Ni–Mn–In Heusler martensites
Authors: Nevgi R , Priolkar K R , Acet M
Published: February 2021

Fe doping in Ni2Mn1.5In0.5 results in suppression of the martensitic phase via two contrasting routes. In Ni2Mn1.5 − x
Fe
x
In0.5, the martensitic phase is converted to a strain glassy phase, while in Ni2 − y
Fe
y
Mn1.5In0.5, a cubic ferromagnetic phase results at the expense of the martensite. Careful studies of magnetic and structural properties reveal the presence of the impurity γ-(Fe,Ni) phase as the reason for the emergence of non-ergodic strain glassy phase when Fe is sought to be doped at Y/Z (Mn) sites of X2YZ Heusler alloy. Whereas attempts to dope Fe in the X (Ni) sublattice result in an A2 type antisite disorder that promotes a ferromagnetic ground state.
Skyrmions near defects
Authors: Derras-Chouk Amel , Chudnovsky Eugene M
Published: February 2021

We study the impact of an exchange-reducing defect on a skyrmion in a thin film of finite thickness. Attraction of the skyrmion to a defect is demonstrated in a lattice model by computing the micromagnetic energy accounting for the exchange, Dzyaloshinskii–Moriya interaction, magnetic anisotropy, and dipole–dipole coupling. The spiraling dynamics of the skyrmion toward the defect is illustrated by solving numerically the full Landau–Lifshitz–Gilbert equations on a lattice and, independently, by solving the Thiele equation, with the two methods in agreement with each other. Depinning of the skyrmion by the current is investigated. We find that the skyrmion deforms when it is close to the defect. Deformation is small in the parameter space far from the phase boundary that determines stability of skyrmions. It increases dramatically near the phase boundary, leading to the transformation of the skyrmion by the defect into a snake-like magnetic domain.
Assessing the efficacy of tomographic reconstruction methods through physical quantification techniques
Authors: Coban Sophia B , Lionheart William R B , Withers Philip J
Published: February 2021

Conventionally the performance of computed tomography (CT) reconstruction algorithms is assessed by a voxel-to-voxel comparison between the object and the reconstructed volume, often using digital phantoms. However the real aim in the CT imaging community is not to develop a reconstruction algorithm to obtain the best-looking images, but one that allows us to extract the relevant information to a desired accuracy. Here, through various case studies, we quantify features of interest for the test object and use these as measures of the efficacy of the reconstructions. Where applicable, we compare the assessment technique against commonly used metrics to measure the quality of a reconstructed solution, and find that in most cases the popular metrics have no relation to the accuracy of the features we extract from a reconstruction. The assessment technique we demonstrate, which we refer to as physical quantification, is used to determine the shape, contacts and size of beads for a test dataset made available via the SophiaBeads Dataset Project. Using this image analysis approach a number of widely used reconstruction methods are evaluated. Our work shows that it is important to choose the optimal reconstruction strategy based on the features you want to quantify from the scan. For example, in our case we found that the shape of the beads could be measured using TV regularization with eight times fewer projections than the other methods, or that reconstructions obtained via many but noisy projections yield as accurate results as those obtained via less noisy but fewer projections.
Investigations into the sensing mechanism of acoustic emission sensors for particle size measurement in a particular case: normal incidence
Authors: Zhang Guoqiang , Yan Yong , Hu Yonghui , Zheng Ge
Published: February 2021

In situ continuous particle size measurement is desirable in a variety of industries. Acoustic emission (AE) is a particularly suitable technique to achieve on-line continuous sizing of particles in pneumatic conveying pipelines, which utilizes the AE signals due to the impact of particles with a waveguide protruding into the particle flow. Although early attempts have been made to reveal the relationship between the AE parameters and the particle size, the fundamental sensing mechanism of the AE-based technique for particle size measurement is still not established. For instance, the effect of particle size distribution on several AE parameters remains to be examined. This article aims to gain an in-depth understanding of the AE sensing mechanism for on-line particle sizing by quantifying the parameters of the AE signal, including peak amplitude, count, rise time, duration, energy and root-mean-square value. A theoretical model considering the energy dissipation during plastic impact is also developed to determine the particle size from the AE signal. The proposed method is verified through experimental tests with glass beads on a single-particle test rig. The experimental results obtained indicate that the proposed method is feasible to infer particle size information from the energy of an impact event. The particle size can be measured with a relative error mostly within

±
10
%

over a range from 0.4 mm to 1.2 mm.
S/Mo ratio and petal size controlled MoS2 nanoflowers with low temperature metal organic chemical vapor deposition and their application in solar cells
Authors: Park Jaeseo , Park Hyeji , Park Suho , Thi Thuy Nguyen , Mun Jihun , Kim Junoh , Lee Sang Jun , Ku Zahyun , Kang Sang-Woo
Published: February 2021

Vertically aligned two-dimensional (2D) molybdenum disulfide nanoflowers (MoS2 NFs) have drawn considerable attention as a novel functional material with potential for next-generation applications owing to their inherently distinctive structure and extraordinary properties. We report a simple metal organic chemical vapor deposition (MOCVD) method that can grow high crystal quality, large-scale and highly homogeneous MoS2 NFs through precisely controlling the partial pressure ratio of H2S reaction gas, P
SR, to Mo(CO)6 precursor, P
MoP, at a substrate temperature of 250 °C. We investigate microscopically and spectroscopically that the S/Mo ratio, optical properties and orientation of the grown MoS2 NFs can be controlled by adjusting the partial pressure ratio, P
SR/P
MoP. It is also shown that the low temperature MOCVD (LT-MOCVD) growth method can regulate the petal size of MoS2 NFs through the growth time, thereby controlling photoluminescence intensity. More importantly, the MoS2 NFs/GaAs heterojunction flexible solar cell exhibiting a power conversion efficiency of ∼1.3% under air mass 1.5 G illumination demonstrates the utility of the LT-MOCVD method that enables the direct growth of MoS2 NFs on the flexible devices. Our work can pave the way for practical, easy-to-fabricate 2D materials integrated flexible devices in optical and photonic applications.
Effect of doping on the GR/MoS2/GR selector: first-principle calculations
Authors: Dai Yuehua , Li Xing , Yang Bin , Shao Peng , Wang Xiaoqing , Yang Fei
Published: February 2021

In this work, a graphene (GR)/MoS2/GR selector was proposed based on first principle calculations. First, MoS2 was chosen as the resistive switching layer due to its high carrier mobility and was doped with nine kinds of dopants. Semiconductor characteristics were still maintained with P, Si, and Ti doping, while the others showed semimetallic properties. Then, heterostructures were built between metal GR and MoS·X (X = S, P, Si, Ti), and the conductivities of MoS·Si and MoS·Ti were obviously improved with the GR electrode through analysis of the impurity orbital contribution to the band energy. The plane average electrostatic potential and the charge density difference show that the Schottky barrier height and width of the GR/MoS·Si interface were the smallest and that the intensity of the built-in electric field was better than that of GR/MoS2 and GR/MoS·Ti. Finally, GR/MoS·X(X = S, Si, Ti)/GR selectors were proposed, and the electronic transmission shows that the ON-state current (I
on) and nonlinear coefficient of the GR/MoS·Si/GR selector were increased by two and three orders of magnitude, respectively, and the threshold voltage (V
th) was reduced by approximately 1 V, which can better suppress the leakage current in a one-selector one-RRAM cross array. This work may be instructive and valuable for the design and optimization of GR/MoS2/GR selectors.
Optimizing interferences of DUV lithography on SOI substrates for the rapid fabrication of sub-wavelength features
Authors: Karker Olfa , Bange Romain , Bano Edwige , Stambouli Valérie
Published: February 2021

Scalable fabrication of Si nanowires with a critical dimension of about 100 nm is essential to a variety of applications. Current techniques used to reach these dimensions often involve e-beam lithography or deep-UV (DUV) lithography combined with resolution enhancement techniques. In this study, we report the fabrication of <150 nm Si nanowires from SOI substrates using DUV lithography (λ = 248 nm) by adjusting the exposure dose. Irregular resist profiles generated by in-plane interference under masking patterns of width 800 nm were optimized to split the resulting features into twin Si nanowires. However, masking patterns of micrometre size or more on the same photomask does not generate split features. The resulting resist profiles are verified by optical lithography computer simulation based on Huygens−Fresnel diffraction theory. Photolithography simulation results validate that the key factors in the fabrication of subwavelength nanostructures are the air gap value and the photoresist thickness. This enables the parallel top-down fabrication of Si nanowires and nanoribbons in a single DUV lithography step as a rapid and inexpensive alternative to conventional e-beam techniques.
Generalized approach for radiotherapy treatment planning by optimizing projected health outcome: preliminary results for prostate radiotherapy patients
Authors: Wilson Lydia J , Newhauser Wayne D
Published: February 2021

Research in cancer care increasingly focuses on survivorship issues, e.g. managing disease- and treatment-related morbidity and mortality occurring during and after treatment. This necessitates innovative approaches that consider treatment side effects in addition to tumor cure. Current treatment-planning methods rely on constrained iterative optimization of dose distributions as a surrogate for health outcomes. The goal of this study was to develop a generally applicable method to directly optimize projected health outcomes. We developed an outcome-based objective function to guide selection of the number, angle, and relative fluence weight of photon and proton radiotherapy beams in a sample of ten prostate-cancer patients by optimizing the projected health outcome. We tested whether outcome-optimized radiotherapy (OORT) improved the projected longitudinal outcome compared to dose-optimized radiotherapy (DORT) first for a statistically significant majority of patients, then for each individual patient. We assessed whether the results were influenced by the selection of treatment modality, late-risk model, or host factors. The results of this study revealed that OORT was superior to DORT. Namely, OORT maintained or improved the projected health outcome of photon- and proton-therapy treatment plans for all ten patients compared to DORT. Furthermore, the results were qualitatively similar across three treatment modalities, six late-risk models, and 10 patients. The major finding of this work was that it is feasible to directly optimize the longitudinal (i.e. long- and short-term) health outcomes associated with the total (i.e. therapeutic and stray) absorbed dose in all of the tissues (i.e. healthy and diseased) in individual patients. This approach enables consideration of arbitrary treatment factors, host factors, health endpoints, and times of relevance to cancer survivorship. It also provides a simpler, more direct approach to realizing the full beneficial potential of cancer radiotherapy.
Analysis and variable step control of a bidirectional complementary-type inchworm actuator
Authors: Sun Tiantian , Wang Yue , Yan Peng
Published: February 2021

To meet the demands of high speed and large loading capacity in various nanopositioning applications, a voltage sequence based step analysis and the corresponding variable step control strategy are explored for a bidirectional complementary-type inchworm actuator. Specifically, the bidirectional variable step motion can be achieved without significant drop of the loading capacity by controlling the two-channel input voltage sequences, where the variable speed motions can help to achieve more rapid nano-positioning tasks. In particular, we introduce the voltage sequences in the modelling of the step length and the total clamping force for the purpose of achieving controllable bidirectional motion with large loading capacity. Real time control experiments are comprehensively conducted, which demonstrates a bidirectional variable step motion range of ±22 µm is achieved by controlling two-channel input signals. In addition, the actuator with the proposed method has an adjustable total clamping force capable of improving the motion stability and loading capacity in variable step motion, which are favourable to various engineering applications in high speed nanopositioning areas.
Dense rotational twins in superconducting (111)-orientated δ-NbN epitaxial films on 4H-SiC substrates
Authors: Chang Hsiao-Wen , Ranganayakulu Vankayala Krishna , Guan Syu-You , Chen Peng-Jen , Ou Min-Nan , Chen Yang-Yuan , Chuang Tien-Ming , Chang Chia-Seng , Wu Maw-Kuen , Wang Ming-Jye
Published: February 2021

In order to confirm the superconductivity observed in hexagonal ϵ-NbN reported recently, we have deposited NbN film on (0001) 4H-SiC substrate, with good lattice match, intentionally to grow hexagonal NbN phase. The detailed structural analysis show that the deposited films are (111)-orientated δ-NbN phase with dense rotational (60°) twins. Double diffraction effect in selected area electron diffraction and Moiré fringes in high resolution transmission electron microscope images confirm the existence of rotational twins in nanometer scale. The growth of highly twined film results from no energy preference for the two rotational twins of (111)-orientated δ-NbN to bond with the Si-faced (0001) 4H-SiC substrate. These highly twined δ-NbN epitaxial films exhibit high normal state resistivity, lower T
C, but good spatial uniformity of superconducting energy gap. No ϵ-NbN phase was observed in this study which is might due to a low growth temperature of thin film.
Opto-electrical properties of Ni and Mg co-doped CdS thin films prepared by spin coating technique
Authors: Garmim T , Bouabdalli E , Soussi L , El Jouad Z , Mghaiouini R , Louardi A , Hartiti B , El Jouad M , Monkade M
Published: February 2021

In the presented study, (Ni, Mg) co-doped CdS thin films are synthetized using the spin coating method. The Mg incorporation effect on the structural, opto-electrical quality of Cd0.98Ni0.02S with different Mg concentrations (0 wt%, 1wt.%, 3wt, and 5wt.%) are investigated. A polycrystalline nature with a cubic structure oriented to (1 1 1) plane was confirmed by the DRX technique, and the incorporation of Mg in Cd0.98Ni0.02S causes an increase of the grain size. The SEM study exhibits a surface of deposited films is dense and the EDS spectra confirmed the existence of the doped elements. The optical properties show that the doping with 3 at.% of Mg presents the maximum each a value of 90% in visible range, with an increasing in the gap energy from 2.42 eV to 2.49 eV corresponding to increasing of Mg concentration. And also optical parameters were investigated such as α, k, n, ε
r, ε
i, tan δ, σ. The electrical resistivity and conductivity measurements are carried using the four points probe, we find that the electrical resistivity decreases from the 7.30 × 103 (Ohm. cm) to 4.28 × 103 (Ohm. cm) while Mg concentration increases from 0 at% to 5 at%.
Resonance Y-type soliton solutions and some new types of hybrid solutions in the (2+1)-dimensional Sawada–Kotera equation
Authors: Li Jiaheng , Chen Qingqing , Li Biao
Published: February 2021

In this paper, based on N-soliton solutions, we introduce a new constraint among parameters to find the resonance Y-type soliton solutions in (2+1)-dimensional integrable systems. Then, we take the (2+1)-dimensional Sawada–Kotera equation as an example to illustrate how to generate these resonance Y-type soliton solutions with this new constraint. Next, by the long wave limit method, velocity resonance and module resonance, we can obtain some new types of hybrid solutions of resonance Y-type solitons with line waves, breather waves, high-order lump waves respectively. Finally, we also study the dynamics of these interaction solutions and indicate mathematically that these interactions are elastic.
Single pixel imaging based on semi-continuous wavelet transform*
Authors: Gao Chao , Wang Xiaoqian , Wang Shuang , Gou Lidan , Feng Yuling , Jin Guangyong , Yao Zhihai
Published: February 2021

Single pixel imaging is a novel imaging technique, and it becomes a focus of research in recent years due to its advantages such as high lateral resolution and high robustness to noise. Imaging speed is one of the critical shortcomings, which limits the further development and applications of this technique. In this paper, we focus on the issues of imaging efficiency of a single pixel imaging system. We propose semi-continuous wavelet transform (SCWT) protocol and introduce the protocol into the single pixel imaging system. The proposed protocol is something between continuous wavelet transform and discrete wavelet transform, which allows the usage of those smooth (usually non-orthogonal, and they have advantages in representing smooth signals compressively, which can improve the imaging speed of single pixel imaging) wavelets and with limited numbers of measurements. The proposed imaging scheme is studied, and verified by simulations and experiments. Furthermore, a comparison between our proposed scheme and existing imaging schemes are given. According to the results, the proposed SCWT scheme is proved to be effective in reconstructing a image compressively.
Creation and annihilation phenomena of electron and positron pairs in an oscillating field*
Authors: Jiang M , Su D D , Lin N S , Li Y J
Published: February 2021

The combination of an oscillating and a static field is used to study the creation and annihilation phenomena during the pair creation process. The time evolution, spatial density and momentum distribution of the created particles for a fermionic system are presented, which demonstrate that with the increasing static field intensity, the number of the created particles experiences a distinguishable decrease in every period of the oscillating field, which is caused by the annihilation phenomena between the created electrons and positrons.
Renormalizability of leading order covariant chiral nucleon-nucleon interaction *
Authors: Wang Chun-Xuan , Geng Li-Sheng , Long Bingwei
Published: February 2021

In this work, we study the renormalization group invariance of the recently proposed covariant power counting in the case of nucleon-nucleon scattering [Chin. Phys. C 42 (2018) 014103] at leading order. We show that unlike the Weinberg scheme, renormalizaion group invariance is satisfied in the

channel. Another interesting feature is that the

and

channels are correlated. Fixing the relevant low energy constants by fitting to the

phase shifts at

and 25 MeV with cutoff values

MeV, one can describe the

phase shifts relatively well. In the limit of

, the

phase shifts become cutoff-independent, whereas the

phase shifts do not. This is consistent with the Wigner bound and previous observations that the

channel is best treated perturbatively. As for the

and

-

channels, renormalization group invariance is satisfied.
Collisional Penrose process of 4D rotational Einstein-Gauss-Bonnet black holes *
Authors: Liu Yunlong , Zhang Xiangdong
Published: February 2021

The collisional Penrose process of massive spinning particles in a rotational Einstein-Gauss-Bonnet (EGB) black hole background is studied. By numerically solving the equations of motion for spinning particles, we find that the energy extraction efficiency increases monotonically with the decrease of the EGB coupling parameter

. Moreover, the efficiency

increases as the particle spin s grows. We also find that the energy extraction efficiency increases with the decrease of the EGB coupling parameter

. When the EGB coupling constant

, our results reduce to the Kerr case, which has been investigated previously.