bluuebunny/crossref_metadata_2025 huggingface dataset:
Double Beveling on Imaging: A Characteristic Feature of Entry and Exit Penetrating Injury Wound
Authors: Agrawal Amit , Kumar VA Kiran , Kiran NA Sai , Penchalaiah Bathalapalli , Vinay Harsha
Published: August 2020

Beveling of the calvarial bone is reported in firearm exit wounds and stabbing injuries in forensic literature. Beveling in entry wounds is rare. We report a case of a 27-year-old man who sustained a nonfatal penetrating craniofacial injury due to motorbike brake handle, and completely recovered after conservative management. We describe the characteristic inward as well outward beveling on imaging due the penetrating trajectory of the motorbike break handle.
Role of Intraoperative ICP And CPP Measurement for Predicting Surgical Outcome in Severe Traumatic Brain Injury
Authors: VV Ramesh Chandra , Bodapati Chandra Mowliswara Prasad , Paradesi Rajesh
Published: August 2020

Introduction Traumatic brain injury (TBI) is one of the leading causes of mortality and disability worldwide, and optimizing the management of these patients is a continuing challenge. Intraoperative intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were evaluated for use as prognostic indicators after surgery for severe TBI. Although ICP and CPP monitoring is standard postsurgery treatment for TBI, very few studies have reported the use of ICP and CPP values monitored during surgery.

Objectives The objectives of this study were to evaluate the use of intraoperative ICP and CPP values as prognostic indicators and as subjective guidelines for managing severe TBI.

Materials and Methods All patients with severe TBI who underwent surgical decompression and ICP monitoring intraoperatively were included in our study from 2017 to 2018. We measured ICP and CPP values after creation of the first burr hole, after hematoma evacuation, and after wound closure.

Results From the analysis of receiver-operated characteristic (ROC) curves, we observed that ICP initial (cutoff > 28 mm Hg) and CPP initial (cutoff < 44.5 mm Hg) are the best predictors of unfavorable outcomes. Favorable outcome (Glasgow outcome scale [GOS] 4 and 5) and unfavorable outcome (GOS 1–3) after 6 months were achieved in 64.1 and 35.8% of patients, respectively. There was significant difference between the ICP and CPP values which are measured after the first burrhole, after hematoma evacuation, and after scalp closure in both favorable and unfavorable outcomes. The highest positive Pearson’s correlation coefficient is found between GOS and ICP and CPP after first burr hole.

Conclusion Monitoring ICP and CPP during surgery improves management in patients with severe TBI and provides an early prognostic indicator in such patients.
Immunomodulatory Effect of Hypertonic Saline Solution in Traumatic Brain-Injured Patients and Intracranial Hypertension
Authors: Quiñones-Ossa Gabriel A. , Shrivastava Adesh , Perdomo William Andres Florez , Moscote-Salazar Luis R. , Agrawal Amit
Published: August 2020

Traumatic brain injury (TBI) is often associated with an increase in the intracranial pressure (ICP). This increase in ICP can cross the physiological range and lead to a reduction in cerebral perfusion pressure (CPP) and the resultant cerebral blood flow (CBF). It is this reduction in the CBF that leads to the secondary damage to the neural parenchyma along with the physical axonal and neuronal damage caused by the mass effect. In certain cases, a surgical intervention may be required to either remove the mass lesion (hematoma of contusion evacuation) or provide more space to the insulted brain to expand (decompressive craniectomy). Whether or not a surgical intervention is performed, all these patients require some form of pharmaceutical antiedema agents to bring down the raised ICP. These agents have been broadly classified as colloids (e.g., mannitol, glycerol, urea) and crystalloids (e.g., hypertonic saline), and have been used since decades. Even though mannitol has been the workhorse for ICP reduction owing to its unique properties, crystalloids have been found to be the preferred agents, especially when long-term use is warranted. The safest and most widely used agent is hypertonic saline in various concentrations. Whatever be the concentration, hypertonic saline has created special interest among physicians owing to its additional property of immunomodulation and neuroprotection. In this review, we summarize and understand the various mechanism by which hypertonic saline exerts its immunomodulatory effects that helps in neuroprotection after TBI.
The Effect of Iodium 30c on Experimental Visceral Leishmaniasis
Authors: Joshi Jyoti , Bandral Chetna , Manchanda Raj Kumar , Khurana Anil , Nayak Debadatta , Kaur Sukhbir
Published: August 2020

Background Leishmaniasis is one of several neglected tropical diseases that warrant serious attention. A disease of socio-economically poor people, it demands safer and cheaper drugs that help to overcome the limitations faced by the existing anti-leishmanials. Complementary or traditional medicines might be a good option, with an added advantage that resistance may not develop against these drugs. Thus, the present investigation was performed to evaluate the anti-leishmanial efficacy of an ultra-diluted homeopathic medicine (Iodium 30c) in experimental visceral leishmaniasis (VL).

Methods Compliant with strict ethical standards in animal experimentation, the study was performed in-vivo in inbred BALB/c mice which were injected intravenously with 1 × 107 promastigotes of Leishmania donovani before (therapeutic) or after (prophylactic) treatment with Iodium 30c for 30 days. In other groups of mice (n = 6 per group), amphotericin B served as positive control, infected animals as the disease control, while the naïve controls included normal animals; animals receiving only Iodium 30c or Alcohol 30c served as sham controls. The anti-leishmanial efficacy was assessed by determining the hepatic parasite load and analysing percentages of CD4+ and CD8+ T cells. Biochemical analysis and histological studies were performed to check any toxicities.

Results Iodium-treated animals showed a significantly reduced parasite load (to 1503 ± 39 Leishman Donovan Units, LDU) as compared with the infected controls (4489 ± 256 LDU) (p < 0.05): thus, the mean therapeutic efficacy of Iodium 30c was 66.5%. In addition, the population of CD4+ and CD8+ T cells was significantly increased (p < 0.05) after treatment. No toxicity was observed, as evidenced from biochemical and histopathological studies of the liver and kidneys. Efficacy of Iodium 30c prophylaxis was 58.3%, while the therapeutic efficacy of amphotericin B was 85.9%.

Conclusion This original study has shown that Iodium 30c had significant impact in controlling parasite replication in experimental VL, though the effect was less than that using standard pharmaceutical treatment.
Phenotypic Variability of an Inherited Pathogenic Variant in CIC Gene: A New Case Report in Two-Generation Family and Literature Review
Authors: Kishnani Sujata , Riley Kacie , Mikati Mohamad A. , Jiang Yong-hui
Published: August 2020

CIC encodes capicua protein, a transcriptional repressor that is highly expressed in developing brains. A previous study reported pathogenic mutations in the CIC gene in five individuals with significant neurodevelopmental disorders of intellectual disability, epilepsy, and autism spectrum disorder. All these mutations are either de novo or likely due to germline mosaicism. Here we reported a pathogenic mutation (c.2694dupC; p.K899Qfs X32: NM_015125) in the CIC gene in three members of a two-generation family presenting with neurodevelopmental impairment but has significant phenotypic variability. Interestingly, loss of function variants of somatic origin are frequently found in cancers of brain and other organs. We summarized germline and somatic pathogenic or loss of function variants in CIC gene in public genome databases through in silico analysis and published literature. Our findings provided further evidence to support the review of haploinsufficiency of CIC in neurodevelopmental disorder, in addition to suggesting a strong modifier effect for the CIC mutations.
Association of Plasma Biomarkers for Angiogenesis and Proteinopathy in Indian Amyotrophic Lateral Sclerosis Patients
Authors: Modgil Shweta , Khosla Radhika , Tiwari Abha , Sharma Kaushal , Anand Akshay
Published: August 2020

Abstarct

Background Amyotrophic lateral sclerosis (ALS) is a rare motor neuron disease with progressive degeneration of motor neurons. Various molecules have been explored to provide the early diagnostic/prognostic tool for ALS without getting much success in the field and miscellaneous reports studied in various population.

Objective The study was aimed to see the differential expression of proteins involved in angiogenesis (angiogenin [ANG], vascular endothelial growth factor [VEGF], vascular endothelial growth factor receptor 2 [VEGFR2], etc), proteinopathy (transactive response DNA binding protein-43 [TDP-43] and optineurin [OPTN]), and neuroinflammation (monocyte chemoattractant protein-1[MCP-1]) based on the characteristics of ALS pathology. Though, suitable panel based on protein expression profile can be designed to robust the ALS identification by enhancing the prognostic and diagnostic efficacy for ALS.

Methods A total of 89 ALS patients and 98 nonneurological controls were analyzed for the protein expression. Expression of angiogenic (VEGF, VEGFR2, and ANG), neuroinflammation (MCP-1), and proteinopathy (TDP-43 and OPTN) markers were estimated in plasma of the participants. Proteins were normalized with respective value of total protein before employing statistical analysis.

Results Analysis has exhibited significantly reduced expression of angiogenic, proteinopathy, and neuroinflammation biomarkers in ALS patients in comparison to controls. Spearman’s correlation analysis has showed the positive correlation to each protein.

Conclusion Altered expression of these proteins is indicating the prominent function in ALS pathology which may be interdependent and may have a synergistic role. Hence, a panel of expression can be proposed to diagnose ALS patient which may also suggest the modulation of therapeutic strategy according to expression profile of patient.
Complications and Factors Associated with Reoperation following Total Wrist Fusion
Authors: Hazewinkel M. H. J. , Lans Jonathan , Lunn Kiera N. , Garg Rohit , Eberlin Kyle R. , Chen Neal C.
Published: August 2020

Background Total wrist fusion can be elected to relieve pain in patients with osteoarthritis and rheumatoid arthritis. This study aimed to investigate the overall complications and the factors associated with reoperation and soft tissue complication after total wrist fusion.

Methods We retrospectively identified adult patients who underwent total wrist fusion using Current Procedural Terminology (CPT) codes, International Classification of Diseases, Ninth and Tenth Revision (ICD-9 and ICD-10) and verified these by medical chart review. We included patients (n = 215) who were treated at a single institutional system from January 1, 2002 to January 1, 2019. The mean age was 53.3 ± 15.0 years and the median follow-up was 6.1 years (interquartile range [IQR] =1.7–9.0). The most common indications for wrist fusion included inflammatory arthritis (n = 66, 31%), degenerative arthritis (n = 59, 27%), and posttraumatic arthritis (n = 47, 22%). All wrist fusions were performed using a dorsal fusion plate or dorsal spanning plate, either with a local autograft (n = 167, 78%), iliac crest autograft (n = 2, 1.0%), allograft (n = 7, 3.3%), a combination of both (n = 16, 7.4%), or without a graft (n = 23, 11%). We performed a multivariable logistic regression to evaluate factors associated with reoperation. In addition, we performed a similar analysis to identify the factors associated with soft tissue complication after total wrist fusion.

Results Forty-one (19%) patients underwent reoperation at a median of 6.9 months (IQR = 3.9–18). The indications included symptomatic implants (n = 12, 27%), implant failures (n = 8, 20%), infections (n = 7, 17%), and nonunions (n = 6, 15%). In multivariable analysis, total wrist fusion of the dominant hand (odds ratio [OR]: 2.2, 95% confidence interval [CI]: 1.1–4.7, p = 0.033) was associated with a higher reoperation rate. Soft tissue complications occurred in 20 patients (9.3%) consisting of hematomas (n = 8, 3.7%), observed blistering (n = 5, 2.3%), and observed wound dehiscence (n = 4, 1.9%). In multivariable analysis, smoking (OR: 2.5, CI: 0.95–6.4, p = 0.010) was independently associated with soft tissue complication after total wrist fusion. Seventy-two (33%) patients had a postoperative complication including symptomatic hardware (n = 16, 7.4%), implant failure (n = 11, 5.1%), infection (n = 11, 5.1%), nonunion (n = 8, 3.7%), and carpal tunnel syndrome (n = 4, 1.9%).

Conclusion Roughly one-third (33%) of the patients undergoing total wrist fusion experience a postoperative complication and 19% of the patients underwent a reoperation. Total wrist fusion of the dominant hand results in higher reoperation rates. The risk of a soft tissue complication after total wrist fusion is increased in smokers.
Pyrocardan Trapeziometacarpal Joint Arthroplasty—Medium-Term Outcomes
Authors: Logan James , Peters Susan E. , Strauss Ruby , Manzanero Silvia , Couzens Gregory B. , Ross Mark
Published: August 2020

Objective Pyrocardan trapeziometacarpal interposition implant is a free intra-articular spacer composed of pyrocarbon. This biconcave resurfacing implant, both ligament and bone-stock sparing, is indicated for use in early-to-moderate stage trapeziometacarpal osteoarthritis. It was hypothesized that the postoperative outcome measures of the Pyrocardan implant would be comparable to those seen with ligament reconstruction and tendon interposition (LRTI) surgeries and those reported by the designer of the implant, Phillipe Bellemère, but that strength would be greater than for LRTI.

Methods In this prospective case series, 40 Pyrocardan implants were performed in 37 patients. Average age was 58 years (range: 46–71). Patients were assessed preoperatively, 3 months, 6 months, 1 year, 2 years, and beyond (long term) wherever possible.

Results There have been no major complications or revision surgeries for the series. Average follow-up was 29 months (range: 12 months–7 years). Twenty-eight joints were assessed at over 2 years post index surgery. Outcome measure scores improved from preoperative assessment to the most recent follow-up equal or greater than 2 years. Average grip strength at 2 years was 30 kg, as compared with 19.6 kg in an age-matched cohort who underwent trapeziectomy and 25 kg in Bellemère's original series of Pyrocardan implants.

Conclusions Pyrocardan interposition arthroplasty appears to be a safe, effective treatment for trapeziometacarpal arthritis. Patient-reported clinical outcomes were at least equivalent to LRTI and are comparable to Bellemère's original series. Grip and pinch strength appear to be better than LRTI.

Level of Evidence This is a Level III, prospective observational cohort study.
The Anticoagulant and Nonanticoagulant Properties of Heparin
Authors: Beurskens Danielle M. H. , Huckriede Joram P. , Schrijver Roy , Hemker H. Coenraad , Reutelingsperger Chris P. , Nicolaes Gerry A. F.
Published: August 2020

Heparins represent one of the most frequently used pharmacotherapeutics. Discovered around 1926, routine clinical anticoagulant use of heparin was initiated only after the publication of several seminal papers in the early 1970s by the group of Kakkar. It was shown that heparin prevents venous thromboembolism and mortality from pulmonary embolism in patients after surgery. With the subsequent development of low-molecular-weight heparins and synthetic heparin derivatives, a family of related drugs was created that continues to prove its clinical value in thromboprophylaxis and in prevention of clotting in extracorporeal devices. Fundamental and applied research has revealed a complex pharmacodynamic profile of heparins that goes beyond its anticoagulant use. Recognition of the complex multifaceted beneficial effects of heparin underscores its therapeutic potential in various clinical situations. In this review we focus on the anticoagulant and nonanticoagulant activities of heparin and, where possible, discuss the underlying molecular mechanisms that explain the diversity of heparin's biological actions.
Staged Buccal Mucosa Graft Urethroplasty for Proximal Hypospadias in Children: A Short- to Mid-Term Follow-Up Retrospective Study
Authors: Chen Sen , Li Yangqun , Ma Ning , Wang Weixin , Xu Lisi , Yang Zhe
Published: August 2020

Introduction The aim of this study is to report our experience with modified staged buccal mucosa graft urethroplasty for the repair of proximal hypospadias in children and adolescents.

Materials and Methods A total of 183 patients were treated at the Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between 2010 and 2019. The patients were grouped according to age: (1) within 1.5-year-old group, (2) prepuberty group (Tanner stage 1), and (3) puberty group.

Results In total, 153 patients were included in this study. Thirty-six patients had complications: seven after stage one; 29 after stage two; one patient had two complications. Maximum flow rates were 11.80 ± 1.46 mL/s in the 1.5-year-old group, 13.24 ± 2.61 mL/s in the prepuberty group, and 13.60 ± 2.20 mL/s in the puberty group (p = 0.199). Average flow rates were 6.86 ± 1.37, 7.94 ± 1.74, and 7.88 ± 1.22 mL/s, respectively (p = 0.203). The optimal hypospadias objective scoring evaluation score of 16 was seen in 117 patients (76%), the score of 15 in 23 patients (15%), 14 in 10 (7%), and 13 in 3 patients (2%). Patients with an uncomplicated treatment (no complication) had a higher clinical outcome than patients with a complication (15.8 ± 0.53 vs. 15.3 ± 0.97, with or without complication, p = 0.000). Multivariable analyses showed that previous treatment was closely related to the complication rate (p = 0.016).

Conclusion The modified procedure allows for two-stage repair of proximal hypospadias with good results with a low complication rate and good functional results. Delaying operation did not increase complication rates in our research.
Transition to Adulthood for Pediatric Moyamoya Patients
Authors: Scott R Michael , Smith Edward R.
Published: August 2020

Moyamoya is a progressive arteriopathy of the intracranial vasculature, predominantly affecting the terminal branches of the internal carotid artery. Treatment is predicated on surgical revascularization to reduce the risk of stroke. For patients diagnosed and treated as children, it is important to recognize the long-term implications of the disease, for example, that moyamoya is treatable, but not curable. Pediatric moyamoya patients face unique challenges as they transition to adulthood as a consequence of the chronic nature of this disorder. Successful long-term care requires a strategy that incorporates ongoing longitudinal disease monitoring, coordination of care between physician teams, and anticipation of socioeconomic factors that change over time. This article provides an approach to transition care to adult caregivers for pediatric moyamoya patients with a specific focus on the three key stakeholders in the process: the neurosurgeon, the primary care physician, and the individual patient.
Far Lateral Craniotomy Closure Technique for Preservation of Suboccipital Musculature
Authors: Ali Muhammad Salman , Magill Stephen T. , McDermott Michael W.
Published: August 2020

The far lateral approach is used for accessing pathology at the craniovertebral junction but can be complicated by postoperative suboccipital muscle atrophy. In addition to significant cosmetic deformity, this atrophy can lead to head and neck pain and potentially could contribute to cranio-cervical instability. To address this issue, the senior author began using a single myocutaneous flap without a muscle cuff and securing it directly to the bone using predrilled holes in the bone that resemble a chevron. The method is described and illustrated with an example case. Results from seven consecutive cases are reported since the technique was adopted. Muscle atrophy was measured by calculating area at the level of the occipital condyle and compared with the contralateral side. No significant differences were noted. In conclusion, we have found this to be an excellent closure technique and wanted to present our initial results for consideration by other skull base surgeons.
The Intestinal Flora at Kasai Procedure in Children with Biliary Atresia Appears Not to Affect Postoperative Cholangitis
Authors: Madadi-Sanjani Omid , Schukfeh Nagoud , Uecker Marie , Eckmann Stefanie , Dingemann Jens , Ure Benno M. , Petersen Claus , Kuebler Joachim F.
Published: August 2020

Introduction Evidence supports long-term oral antibiotic prophylaxis to prevent cholangitis after Kasai procedure. Data regarding perioperative intravenous prophylaxis are lacking. Ascending pathogens from the intestine are made responsible for recurrent cholangitis. Therefore, we analyzed the flora in the upper jejunum during the Kasai procedure and their potential impact on postoperative cholangitis.

Materials and Methods In 26 patients, swabs were taken at the bowel prepared for the Roux-en-Y-loop. Our postoperative protocol includes intravenous third-generation cephalosporins for 2 weeks and rectal steroids starting at day 4. Cholangitis was defined as the postoperative reappearance of acholic stools or increase of serum bilirubin in combination with fevers or increase of inflammatory parameters. In this scenario, Tazocin was administered for another 2 weeks.

Results Swabs remained sterile in nine patients (34.6%). In 17 patients (65.4%), gram-positive and gram-negative pathogens were identified; all belonging to physiological intestinal flora. A total of 96.2% pathogens were covered by the antibiotic prophylaxis. The cholangitis incidence was 55.6% in the sterile cohort, and 23.5% in the gram-positive and gram-negative cohort (p = 0.06). In the cholangitis cohort, no significant differences were detected for the age at Kasai and the pre- and postoperative total bilirubin.

Conclusion We found that our antibiotic regiment covered bacteria in the upper gastrointestinal (GI) tract in the majority of our patients at the time of Kasai. Nonetheless, a significant proportion of patients developed signs of cholangitis. There was no higher rate of cholangitis in patients with resistant bacteria. Thus, our data do not support the hypothesis of extended postoperative intravenous antibiotics to prevent ascending cholangitis.
Education, Marriage, and Employment in People with Epilepsy: The Barriers that Patients Perceive
Authors: Asadi-Pooya Ali A. , Homayoun Maryam , Keshavarz Shahla
Published: August 2020

Objectives We surveyed people with epilepsy (PWE) and uncontrolled seizures on the challenges which they have had in their lives with respect to educational achievement, employment, and marriage. We tried to scrutinize their reasons and perceptions for their social underachievement and difficulties.

Materials and Methods Adult patients above 25 years of age, with epileptic seizures for more than 5 years, who were investigated at Shiraz Comprehensive Epilepsy Center, from January until March 2019, were studied. We prepared a questionnaire for our study and asked whether they have any college education? If they have ever married? And, if they are employed?

Results Seventy patients enrolled in our study. Age of the patients was 33 ± 6 years (range: 26–59 years) and their age at onset of epilepsy was 14 ± 9 years (range: 0–35 years). Forty-four patients (63%) never received any college education; 30 patients (43%) were single; and finally, 37 patients (53%) were unemployed. The most common reasons perceived by the patients for these life challenges were functional disability (e.g., inability to study or to work), social discrimination and stigmatization, and uncontrolled seizures and the associated consequences (i.e., fear of having seizures).

Conclusion Many PWE (both men and women) and uncontrolled seizures suffer from social underachievement and challenges in their daily lives. Various strategies may help PWE to overcome these challenges.
Breathing patterns and ambient nanoparticle size affect interactions deep within the lungs
Authors: Bandari Anashe
Published: August 2020

The interaction between breathing patterns and nanoparticle depositions were examined by simulating lung-on-a-chip devices.
A general numerical model for rotor aerodynamics based on added mass force
Authors: Li Zhiguo , Gao Zhiying , Chen Yongyan , Zhang Xiaoxue , Dai Yuanjun , Wang Jianwen
Published: August 2020

When wind turbines operate in complex atmospheric environments, the flow fields around their blades are complex and unsteady. To capture the lag characteristics of induced velocity when the dynamic environment of a rotor changes, this study further modified the equilibrium wake model using the blade element momentum and acceleration potential theories. In addition, a novel expression for the added mass force mA=128/75ρR3 was derived. Consequently, a numerical aerodynamics model of a rotor with an added mass force was developed. The model was used to calculate the aerodynamic load of a 5 MW wind turbine under steady wind, turbulence, gust, wind direction change, and rapid pitching. The results demonstrated that the numerical model with added mass force could reflect the rotor aerodynamic performance more accurately than its counterpart. The fluctuation amplitudes of the flapwise and edgewise bending moments of the blade root were smaller than those from the equilibrium wake model. The overshoot in loading, which was caused by the added mass force during pitching, could not be ignored. The research results were compared with experimental data from the National Renewable Energy Laboratory. It was found that the proposed model provided a new strategy for calculating the added mass force and predicted rotor aerodynamic loads more accurately than the model without added mass force.
Simple, compact, high-resolution monochromatic x-ray source for characterization of x-ray calorimeter arrays
Authors: Leutenegger M. A. , Eckart M. E. , Moseley S. J. , Rohrbach S. O. , Black J. K. , Chiao M. P. , Kelley R. L. , Kilbourne C. A. , Porter F. S.
Published: August 2020

X-ray calorimeters routinely achieve very high spectral resolution, typically a few eV full width at half maximum (FWHM). Measurements of calorimeter line shapes are usually dominated by the natural linewidth of most laboratory calibration sources. This compounds the data acquisition time necessary to statistically sample the instrumental line broadening and can add systematic uncertainty if the intrinsic line shape of the source is not well known. To address these issues, we have built a simple, compact monochromatic x-ray source using channel cut crystals. A commercial x-ray tube illuminates a pair of channel cut crystals that are aligned in a dispersive configuration to select the Kα1 line of the x-ray tube anode material. The entire device, including the x-ray tube, can be easily hand-carried by one person and may be positioned manually or using a mechanical translation stage. The output monochromatic beam provides a collimated image of the anode spot with magnification of unity in the dispersion direction (typically 100 μm–200 μm for the x-ray tubes used here) and is unfocused in the cross-dispersion direction so that the source image in the detector plane appears as a line. We measured output count rates as high as 10 count/s/pixel for the Hitomi soft x-ray spectrometer, which had 819 μm square pixels. We implemented different monochromator designs for energies of 5.4 keV (one design) and 8.0 keV (two designs), which have effective theoretical FWHM energy resolution of 0.125 eV, 0.197 eV, and 0.086 eV, respectively; these are well-suited for optimal calibration measurements of state-of-the art x-ray calorimeters. We measured an upper limit for the energy resolution of our Cr Kα1 monochromator of 0.7 eV FWHM at 5.4 keV, consistent with the theoretical prediction of 0.125 eV.
Derivation of the friction and thermal force for SOLPS-ITER multicomponent plasma modeling
Authors: Sytova Elizaveta , Coster David , Senichenkov Ilya , Kaveeva Elizaveta , Rozhansky Vladimir , Voskoboynikov Sergey , Veselova Irina , Bonnin Xavier P
Published: August 2020

SOLPS-ITER is a code package for tokamak plasma boundary modeling comprising the B2.5 plasma fluid code and the EIRENE neutral kinetic code. The form of the momentum balance equation, used in the SOLPS-ITER code before version 3.0.6 (and in all previous versions of SOLPS codes), was simplified due to numerical reasons—the electric field term was replaced by the electron gradient pressure term; friction and thermal force terms were derived using the trace impurity assumption. It has now been decided to switch back to the general Braginskii version of this equation. Derivation of the new form of the parallel friction and thermal force terms has been required to allow the use of the general form of the equation and allow more accurate modeling of multicomponent plasmas. The new form is based on the theoretical description of multicomponent plasma derived by V. M. Zhdanov [Plasma Phys. Controlled Fusion 44(10), 2283 (2002)]. In the present paper, a detailed derivation of these terms is presented, and their implementation into the SOLPS-ITER code package is discussed.
Micro-liquid enclosure array and its semi-automated assembling system for x-ray free-electron laser diffractive imaging of samples in solution
Authors: Kimura Takashi , Suzuki Akihiro , Yang Ying , Niida Yoshiya , Nishioka Akiko , Takei Masashi , Wei Jinjian , Mitomo Hideyuki , Matsuo Yasutaka , Niikura Kenichi , Ijiro Kuniharu , Tono Kensuke , Yabashi Makina , Ishikawa Tetsuya , Oshima Tairo , Bessho Yoshitaka , Joti Yasumasa , Nishino Yoshinori
Published: August 2020

We developed micro-liquid enclosure arrays (MLEAs) for holding solution samples in coherent diffractive imaging (CDI) using x-ray free-electron lasers (XFELs). Hundreds of fully isolated micro-liquid enclosures are arranged in a single MLEA chip for efficient measurement, where each enclosure is destroyed after exposure to a single XFEL pulse. A semi-automated MLEA assembling system was also developed to enclose solution samples into MLEAs efficiently at high precision. We performed XFEL-based CDI experiments using MLEAs and imaged in-solution structures of self-assembled gold nanoparticles. The sample hit rate can be optimized by adjusting solution concentration, and we achieved a single-particle hit rate of 31%, which is not far from the theoretical upper limit of 37% derived from the Poisson statistics. MELAs allow us to perform CDI measurement under controlled solution conditions and will help reveal the nanostructures and dynamics of particles in solution.
Simulation of nanoparticle transport and adsorption in a microfluidic lung-on-a-chip device
Authors: Amin Arefi S. M. , Tony Yang Cheng Wei , Sin Don D. , Feng James J.
Published: August 2020

The effect of air-borne nanoparticles (NPs) on human health is an active area of research, with clinical relevance evidenced by the current COVID-19 pandemic. As in vitro models for such studies, lung-on-a-chip (LOAC) devices can represent key physical and physiological aspects of alveolar tissues. However, widespread adoption of the LOAC device for NP testing has been hampered by low intra-laboratory and inter-laboratory reproducibility. To complement ongoing experimental work, we carried out finite-element simulations of the deposition of NPs on the epithelial layer of a well-established LOAC design. We solved the Navier–Stokes equations for the fluid flow in a three-dimensional domain and studied the particle transport using Eulerian advection–diffusion for fine NPs and Lagrangian particle tracking for coarse NPs. Using Langmuir and Frumkin kinetics for surface adsorption and desorption, we investigated NP adsorption under different exercise and breath-holding patterns. Conditions mimicking physical exercise, through changes in air-flow volume and breathing frequency, enhance particle deposition. Puff profiles typical of smoking, with breath-holding between inhalation and exhalation, also increase particle deposition per breathing cycle. Lagrangian particle tracking shows Brownian motion and gravitational settling to be two key factors, which may cooperate or compete with each other for different particle sizes. Comparisons are made with experimental data where possible and they show qualitative and semi-quantitative agreement. These results suggest that computer simulations can potentially inform and accelerate the design and application of LOAC devices for analyzing particulate– and microbe–alveolar interactions.
A high-pressure flow through test vessel for neutron imaging and neutron diffraction-based strain measurement of geological materials
Authors: Carmichael J. R. , Polsky Y. , An K. , Anovitz L. M. , Bingham P. , Dessieux Luc , Ekici K. , Frost M. , Pemberton S.
Published: August 2020

Neutron scattering and neutron imaging have emerged as powerful methods for experimentally investigating material deformation and fluid flow in the interior of otherwise inaccessible or opaque structures. This paper describes the design and provides example uses of a pressure cell developed for investigating such behaviors within geological materials. The cell can accommodate cylindrical samples with diameters up to 38.1 mm and lengths up to 154 mm. Ports in the cell and a pressure isolating sleeve around the sample allow the independent application of confining pressure up to 69 MPa and axial pressure up to 34.5 MPa. Two material versions of the cell have been manufactured and used to date. An aluminum version is typically used for temperatures below 40 °C, because of its relative transparency to neutrons, while a titanium version, which is comparatively more neutron attenuating, is used for experiments requiring triaxial pressurization under conditions up to 350 °C. The pressure cells were commissioned at the VULCAN engineering diffractometer at the Oak Ridge National Laboratory (ORNL), Spallation Neutron Source, and have since been used at the ORNL high flux isotope reactor CG1-D imaging beamline, National Institute of Standard and Technology (NIST) BT-2, and NIST NG6 imaging beamlines.
Transforming Gaussian correlations. Applications to generating long-range power-law correlated time series with arbitrary distribution
Authors: Carpena Pedro , Bernaola-Galván Pedro A. , Gómez-Extremera Manuel , Coronado Ana V.
Published: August 2020

The observable outputs of many complex dynamical systems consist of time series exhibiting autocorrelation functions of great diversity of behaviors, including long-range power-law autocorrelation functions, as a signature of interactions operating at many temporal or spatial scales. Often, numerical algorithms able to generate correlated noises reproducing the properties of real time series are used to study and characterize such systems. Typically, many of those algorithms produce a Gaussian time series. However, the real, experimentally observed time series are often non-Gaussian and may follow distributions with a diversity of behaviors concerning the support, the symmetry, or the tail properties. It is always possible to transform a correlated Gaussian time series into a time series with a different marginal distribution, but the question is how this transformation affects the behavior of the autocorrelation function. Here, we study analytically and numerically how the Pearson’s correlation of two Gaussian variables changes when the variables are transformed to follow a different destination distribution. Specifically, we consider bounded and unbounded distributions, symmetric and non-symmetric distributions, and distributions with different tail properties from decays faster than exponential to heavy-tail cases including power laws, and we find how these properties affect the correlation of the final variables. We extend these results to a Gaussian time series, which are transformed to have a different marginal distribution, and show how the autocorrelation function of the final non-Gaussian time series depends on the Gaussian correlations and on the final marginal distribution. As an application of our results, we propose how to generalize standard algorithms producing a Gaussian power-law correlated time series in order to create a synthetic time series with an arbitrary distribution and controlled power-law correlations. Finally, we show a practical example of this algorithm by generating time series mimicking the marginal distribution and the power-law tail of the autocorrelation function of real time series: the absolute returns of stock prices.
Monitoring the Joule heating profile of GaN/SiC high electron mobility transistors via cross-sectional thermal imaging
Authors: Pavlidis G. , Hilton A. M. , Brown J. L. , Heller E. R. , Graham S.
Published: August 2020

The development of high-quality gallium nitride (GaN) high electron mobility transistors (HEMTs) has provided opportunities for the next generation of high-performance radio frequency and power electronics. Operating devices with smaller length scales at higher voltages result in excessively high channel temperatures, which reduce performance and can have detrimental effects on the device's reliability. The thermal characterization of GaN HEMTs has traditionally been captured from either the top or bottom side of the device. Under this configuration, it has been possible to map the lateral temperature distribution across the device with optical methods such as infrared and Raman thermometry. Due to the presence of the gate metal, however, and often also the addition of a metal air bridge and/or field plate, the temperature of the GaN channel under the gate is typically inferred by numerical simulations. Furthermore, measuring the vertical temperature gradient across multiple epitaxial layers has shown to be challenging. This study proposes a new cross-sectional imaging technique to map the vertical temperature distribution in GaN HEMTs. Combining advanced cross-sectioning processing with the recently developed near bandgap transient thermoreflectance imaging technique, the full transient thermal distribution across a GaN HEMT is achieved. The cross-sectional thermal imaging of the GaN channel is used to study the effects of biasing on the Joule heating profile. Overall, the direct measurement of the GaN channel, capturing both the vertical and lateral gradient, will provide deeper insight into the device's degradation physics and supply further experimental data to validate previously developed electrothermal models.
Dual-band microwave detector based on magnetic tunnel junctions
Authors: Zhang Like , Cai Jialin , Fang Bin , Zhang Baoshun , Bian Lifeng , Carpentieri Mario , Finocchio Giovanni , Zeng Zhongming
Published: August 2020

The spin-torque diode effect has enabled a nanoscale category of microwave detectors, which are characterized by ultrahigh sensitivities and can work at sub-μW input power. Here, we develop such detectors having a dual-band rectification curve centered at the frequencies f1 and f2 and with a rectified voltage of opposite sign (Vf1>0 and Vf2<0). By selecting the proper bias current and field, the sensitivity is larger than 8000 mV/mW. The physics behind this behavior is the simultaneous excitation of different magnetization oscillation modes and the injection locking mechanism. This dual-band microwave detector could find potential applications in the Internet of Things by reducing the size and the power consumption for signal demodulation in a binary frequency shift keying modulation/demodulation scheme.
Fractional GCEs behaviors merged: Prediction to the photoacoustic signal obtained with subdiffusive and superdiffusive operators
Authors: Somer Aloisi , Novatski Andressa , Carlos Serbena Francisco , Kaminski Lenzi Ervin
Published: August 2020

In this work, we developed a theoretical model with anomalous thermal diffusion by considering the modified Generalized Cattaneo Equations (GCEs) of Compte and Metzler, GCEI and GCEII, merged in a single operator by a linear combination in function of the fractional derivative order. This operator was compared with the generalization of Youssef for GCEIII. The range of the superdiffusive and subdiffusive regions was determined through phase velocity. In conclusion, both operators present unexpected sub- and superdiffusive intervals. Moreover, the temperature variation due to the heating by a pulsed light beam was determined. At the end, the photoacoustic signal for opaque samples was simulated varying the relaxation time and the fractional-order derivative.
Self-acceleration and energy channeling in the saturation of the ion-sound instability in a bounded plasma
Authors: Xu Liang , Smolyakov Andrei , Janhunen Salomon , Kaganovich Igor
Published: August 2020

A novel regime of the saturation of the Pierce-type ion-sound instability in a bounded ion-beam-plasma system is revealed in 1D particle-in-cell simulations. It is found that the saturation of the instability is mediated by the oscillating virtual anode potential structure. The periodically oscillating potential barrier separates the incoming beam ions into two groups. One component forms a supersonic beam, which is accelerated to an energy exceeding the energy of the initial cold ion beam. The other component is organized as a self-consistent phase space structure of trapped ions with a wide energy spread—the ion hole. The effective temperature (energy spread) of the ions trapped in the hole is lower than the initial beam energy. In the final stage, the ion hole expands over the whole system length.
Simple hydrogenic estimates for the exchange and correlation energies of atoms and atomic ions, with implications for density functional theory
Authors: Kaplan Aaron D. , Santra Biswajit , Bhattarai Puskar , Wagle Kamal , Chowdhury Shah Tanvir ur Rahman , Bhetwal Pradeep , Yu Jie , Tang Hong , Burke Kieron , Levy Mel , Perdew John P.
Published: August 2020

Exact density functionals for the exchange and correlation energies are approximated in practical calculations for the ground-state electronic structure of a many-electron system. An important exact constraint for the construction of approximations is to recover the correct non-relativistic large-Z expansions for the corresponding energies of neutral atoms with atomic number Z and electron number N = Z, which are correct to the leading order (−0.221Z5/3 and −0.021Z ln Z, respectively) even in the lowest-rung or local density approximation. We find that hydrogenic densities lead to Ex(N, Z) ≈ −0.354N2/3Z (as known before only for Z ≫ N ≫ 1) and Ec ≈ −0.02N ln N. These asymptotic estimates are most correct for atomic ions with large N and Z ≫ N, but we find that they are qualitatively and semi-quantitatively correct even for small N and N ≈ Z. The large-N asymptotic behavior of the energy is pre-figured in small-N atoms and atomic ions, supporting the argument that widely predictive approximate density functionals should be designed to recover the correct asymptotics. It is shown that the exact Kohn–Sham correlation energy, when calculated from the pure ground-state wavefunction, should have no contribution proportional to Z in the Z → ∞ limit for any fixed N.
Local control of an array of the diffusively coupled FitzHugh–Nagumo oscillators via repulsive mean field
Authors: Adomaitienė Elena , Ašmontas Steponas , Bumelienė Skaidra , Tamaševičius Arūnas
Published: August 2020

A feedback method for stabilizing the steady states in an array of the coupled nonlinear oscillators is described. The method employs two complementary techniques: the pinning control accomplished via a single accidentally accessed (or randomly chosen) oscillator and the repulsive mean field. Analytical, numerical, and experimental results are presented for a chain of the diffusively coupled FitzHugh–Nagumo (FHN) type oscillators with an exponential activation function. The experiment has been performed using analog electrical circuit, imitating dynamical behavior of the spiking FHN oscillators.
Darcy–Bénard–Bingham convection
Authors: Rees D. A. S.
Published: August 2020

The present paper is the first to consider Darcy–Bénard–Bingham convection. A Bingham fluid saturates a horizontal porous layer that is subjected to heating from below. It is shown that this simple extension to the classical Darcy–Bénard problem is linearly stable to small-amplitude disturbances but nevertheless admits strongly nonlinear convection. The Pascal model for a Bingham fluid occupying a porous medium is adopted, and this law is regularized in a frame-invariant manner to yield a set of two-dimensional governing equations that are then solved numerically using finite difference approximations. A weakly nonlinear theory of the regularized Pascal model is used to show that the onset of convection is via a fold bifurcation. Some parametric studies are performed to show that this nonlinear onset of convection arises at increasing values of the Darcy–Rayleigh number as the Rees–Bingham number increases and that, for a fixed Rees–Bingham number, the wavenumber at which the rate of heat transfer is maximized increases with the Darcy–Rayleigh number.
Rapid and even spreading of complex fluids over a large area in porous substrates
Authors: Agrawal Prashant , Kumar Hemant , Kumar Prasoon
Published: August 2020

Rapid and even spreading of complex fluids over a large area on substrates like paper is required for chemical and biological sensing applications. Non-Newtonian flow behavior and the presence of multi-phase components pose a significant challenge to uniform flow in porous media. Specifically in the case of blood, for biosensing applications, fast spread on a large area is required to avoid coagulation and non-uniform component spread. In this work, we have developed a filter paper-based device to resolve this spreading challenge. We sandwich the filter paper between a matrix of nanofibrous membrane backed by polyethylene terephthalate (PET) sheets, forming a multi-scale porous network: one within the filter paper and the other between the PET sheet and the filter paper. By doing so, we decrease the overall resistance to flow while maintaining the same capillary suction pressure to obtain a quick, uniform spread of dyed liquids, milk solutions, and whole blood. The device design and concepts used here can be used in paper microfluidic applications and to develop devices for dried blood spot analysis, which utilize this fast flow while maintaining even spreading over a large area.
Pulse length dependent near-infrared ultrafast nonlinearity of gold by self-phase modulation
Authors: Tuniz Alessandro , Palomba Stefano , de Sterke C. Martijn
Published: August 2020

We investigate the pulse length dependence of the third-order nonlinear response of a gold film using pulse widths between 325 and 650 fs at λ=1320 nm via a sensitive cut-pulse technique that measures background-free self-phase modulation. We find a cubic dependence of the transmitted nonlinear power on incident peak intensity that is independent of the pulse width in this range to within experimental accuracy. We estimate a value of χ3=8±3×10−18 m2/V2 by fitting experimental data to numerical simulations accounting for both losses and reflections at each film interface. These results provide valuable insights into near-infrared nonlinear plasmonic device designs.