bluuebunny/crossref_metadata_2025 huggingface dataset:
Is the Additional Effort for an Intraoperative CT Scan Justified for Distal Radius Fracture Fixations? A Comparative Clinical Feasibility Study
Authors: Halvachizadeh Sascha , Berk Till , Pieringer Alexander , Ried Emanuael , Hess Florian , Pfeifer Roman , Pape Hans-Christoph , Allemann Florin
Published: July 2020

Introduction: It is currently unclear whether the additional effort to perform an intraoperative computed tomography (CT) scan is justified for articular distal radius fractures (DRFs). The purpose of this study was to assess radiological, functional, and clinical outcomes after surgical treatment of distal radius fractures when using conventional fluoroscopy vs. intraoperative CT scans. Methods: Inclusion criteria: Surgical treatment of DRF between 1 January 2011 and 31 December 2011, age 18 and above. Group distribution: intraoperative conventional fluoroscopy (Group Conv) or intraoperative CT scans (Group CT). Exclusion criteria: Use of different image intensifier devices or incomplete data. DRF classification according to the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification. Outcome variables included requirement of revision surgeries, duration of surgery, absorbed radiation dose, and requirement of additional CT scans during hospitalization. Results: A total of 187 patients were included (Group Conv n = 96 (51.3%), Group CT n = 91 (48.7%)). AO Classification: Type A fractures n = 40 (50%) in Group Conv vs. n = 16 (17.6%) in Group CT, p < 0.001; Type B: 10 (10.4%) vs. 11 (12.1%), not significant (n.s.); Type C: 38 (39.6%) vs. 64 (70.3%), p < 0.001. In Group Conv, four (4.2%) patients required revision surgeries within 6 months, but in Group CT no revision surgery was required. The CT scan led to an intraoperative screw exchange/reposition in 23 (25.3%) cases. The duration of the initial surgery (81.7 ± 46.4 min vs. 90.1 ± 43.6 min, n.s.) was comparable. The radiation dose was significantly higher in Group CT (6.9 ± 1.3 vs. 2.8 ± 7.8 mGy, p < 0.001). In Group Conv, 11 (11.5%) patients required additional CT scans during hospitalization. Conclusion: The usage of intraoperative CT was associated with improved reduction and more adequate positioning of screws postoperatively with comparable durations of surgery. Despite increased efforts by utilizing the intraoperative CT scan, the decrease in reoperations may justify its use.
The Spectrum of Clinical and Serological Features of COVID-19 in Urban Hemodialysis Patients
Authors: Stock da Cunha Teresa , Gomá-Garcés Elena , Avello Alejandro , Pereira-García Mónica , Mas-Fontao Sebastian , Ortiz Alberto , González-Parra Emilio
Published: July 2020

Introduction: The inherent immunosuppression of uremia increases the susceptibility of hemodialysis patients to infection. There is still limited evidence on hemodialysis patients and COVID-19. The clinical and analytical spectrum and treatment responses and mortality are poorly characterized. Material and Methods: Clinical and analytical features, chest X-ray, polymerase chain reaction (PCR) and antibodies for SARS-CoV-2, treatment and outcomes were analyzed in 48 patients diagnosed with COVID-19 during March and April 2020 in two coordinated Spanish hemodialysis units. Results: In 200 haemodialysis patients, COVID-19 was diagnosed in 48, of whom 22 were PCR positive, eight PCR negative but seroconverted and two were diagnosed on typical clinical grounds. Despite a mean age of 72.6 years, the overall mortality rate was 5/48 (10%). Among the PCR positive patients, 21 (55%) required admission and five (13%) died. PCR positive patients were more often symptomatic and hospitalized and had higher troponin I levels than PCR negative patients, but did not differ in lymphocyte counts, D-dimer or interleukin-6 (IL-6) levels. Among PCR negative COVID-19 patients, three out of 10 (30%) required admission, and none died. The most frequent symptom among the 48 patients was fever (31%), followed by asymptomatic patients (23%). A low number of lymphocytes was the only parameter significantly different between hospitalized and ambulatory COVID-19 patients, independently of PCR status. Conclusions: COVID-19 hemodialysis patients are frequently asymptomatic, and mortality may be lower than previously reported. Diagnosis may be retrospective, based on seroconversion, as PCR may be negative. This information should guide preventive and patient isolation strategies.
Narrow-Margin Excision for Invasive Acral Melanoma: Is It Acceptable?
Authors: Ito Takamichi , Kaku-Ito Yumiko , Wada-Ohno Maiko , Furue Masutaka
Published: July 2020

In this retrospective review of 100 patients with primary invasive acral melanoma, we examined whether narrow-margin excision is warranted for acral melanoma. Patients treated with surgical margins recommended by the National Comprehensive Cancer Network (R-group) were compared to those treated with narrow margins (N-group). A total of 65 patients underwent narrow-margin excision. Positive margin status or local recurrence rarely occurred regardless of the excision margins, whereas fatal events frequently occurred, particularly among the patients with T4 melanoma. The mortality rates of N- and R-group with T1–3 melanomas were similar (1.36 and 1.28 per 100 person-years, respectively). However, patients with T4 melanoma treated with narrow-margin excision had a higher mortality rate (11.44 vs. 5.03 per 100 person-years). Kaplan–Meier analyses showed a worse prognosis in the N-group (p = 0.045) but this group had thicker Breslow thickness (4.21 mm vs. 2.03 mm, p = 0.0013). A multivariate analysis showed that Breslow thickness was an independent risk factor, but surgical margin was not a risk factor for melanoma-specific survival or disease-free survival. In conclusion, although we could not find a difference between the narrow-margin excision and recommended-margin excision in this study, we suggest following current recommendations of guidelines. Our study warrants the prospective collection of data on acral melanoma to better define the prognosis of this infrequent type of melanoma.
Role of Cardiac Computed Tomography for Etiology Evaluation of Newly Diagnosed Heart Failure with Reduced Ejection Fraction
Authors: Im Dong Jin , Youn Jong-Chan , Lee Hye-Jeong , Nam Kyungsun , Suh Young Joo , Hong Yoo Jin , Hur Jin , Kim Young Jin , Choi Byoung Wook , Kang Seok-Min
Published: July 2020

Delayed-enhanced dual-energy computed tomography (DECT) can evaluate the extent and degree of myocardial fibrosis while coronary CT angiography (CCTA) is a widely accepted coronary artery evaluation method. We sought to describe the role of combined cardiac CT for the evaluation of underlying etiology in patients with newly diagnosed heart failure with reduced ejection fraction (HFrEF). Sixty-three consecutive patients (31 men, 63 ± 16 years) with newly diagnosed HFrEF were enrolled in this prospective study. Coronary artery disease and myocardial fibrosis were evaluated on CCTA and DECT, respectively, and the tentative underlying etiologies of heart failure (HF) were determined with combinations of findings from both CTs. Concordance between tentative etiologies from cardiac CT and final etiologies from clinical decisions within a 2-year follow-up was assessed. Eighteen patients were diagnosed with ischemic HF on initial cardiac CT, and the final diagnosis was not changed. Another 45 patients with nonischemic HF included tentative etiologies of dilated cardiomyopathy (n = 32, 71.1%), sarcoidosis or myocarditis (n = 8, 17.8%), amyloidosis (n = 2, 4.4%), noncompaction (n = 2, 4.4%) and arrhythmogenic right ventricular cardiomyopathy (n = 1, 2.2%). Five nonischemic HF patients showed different etiologies between initial cardiac CT and clinical decisions. The concordance between cardiac CT and clinical decisions was 92.1%. A high degree of concordance was achieved between tentative etiologies from cardiac CT and final diagnoses from clinical decisions. Combined cardiac CT is a feasible, safe and effective imaging tool for the initial evaluation of newly diagnosed HFrEF patients.
Real-World Clinical Outcomes Associated with Canagliflozin in Patients with Type 2 Diabetes Mellitus in Spain: The Real-Wecan Study
Authors: Gorgojo-Martínez Juan J. , Gargallo-Fernández Manuel A. , Galdón Sanz-Pastor Alba , Antón-Bravo Teresa , Brito-Sanfiel Miguel , Wong-Cruz Jaime
Published: July 2020

The aims of this multicentric retrospective study were to assess in a real-world setting the effectiveness and safety of canagliflozin 100 mg/d (CANA100) as an add-on to the background antihyperglycemic therapy, and to evaluate the intensification of prior sodium–glucose co-transporter type 2 inhibitor (SGLT-2i) therapy by switching to canagliflozin 300 mg/d (CANA300) in patients with T2DM. One cohort of SGLT2i-naïve patients with T2DM who were initiated on CANA100 and a second cohort of patients with prior background SGLT-2i therapy who switched to CANA300 were included in the study. The primary outcome of the study was the mean change in HbA1c over the follow-up time. In total, 583 patients were included—279 in the cohort of CANA100 (HbA1c 8.05%, weight 94.9 kg) and 304 in the cohort of CANA300 (HbA1c 7.51%, weight 92.0 kg). Median follow-up periods in both cohorts were 9.1 and 15.4 months respectively. CANA100 was associated to significant reductions in HbA1c (−0.90%) and weight (−4.1 kg) at the end of the follow-up. In those patients with baseline HbA1c > 8% (mean 9.25%), CANA100 lowered HbA1c levels by 1.51%. In the second cohort, patients switching to CANA300 experienced a significant decrease in HbA1c (−0.35%) and weight (−2.1 kg). In those patients with baseline HbA1c > 8% (mean 8.94%), CANA300 lowered HbA1c levels by 1.12%. There were significant improvements in blood pressure in both cohorts. No unexpected adverse events were reported. In summary, CANA100 (as an add-on therapy) and CANA300 (switching from prior SGLT-2i therapy) significantly improved several cardiometabolic parameters in patients with T2DM.
Large-Scale Drug Screen Identifies FDA-Approved Drugs for Repurposing in Sickle-Cell Disease
Authors: Cannon Matthew , Phillips Hannah , Smith Sidney , Williams Katie , Brinton Lindsey , Gregory Charles , Landes Kristina , Desai Payal , Byrd John , Lapalombella Rosa
Published: July 2020

Sickle-cell disease (SCD) is a debilitating hematological disorder with very few approved treatment options. Therapeutic reactivation of fetal hemoglobin (HbF) is one of the most pursued methods for ameliorating the systemic manifestations of SCD. Despite this, very few pharmacological agents have advanced to clinical trials or marketing for use. In this study, we report the development of an HbF in situ intracellular immunoblot assay coupled to a high-throughput drug screen to identify Food and Drug Administration (FDA) approved drugs that can be repurposed clinically for treatment of SCD. Using this assay we evaluated the National Institute of Health (NIH) Clinical Collection (NCC), a publicly available library of 725 small molecules, and found nine candidates that can significantly re-express HbF in erythroid cell lines as well as primary erythroblasts derived from SCD patients. Furthermore, we show the strong effects on HbF expression of these candidates to occur with minimal cytotoxicity in 7 of the 9 drugs. Given these data and their proven history of use for other indications, we hypothesize that several of these candidate drugs warrant further investigation for use in SCD.
Secretagogin is Related to Insulin Secretion but Unrelated to Gestational Diabetes Mellitus Status in Pregnancy
Authors: Deischinger Carola , Harreiter Jürgen , Leitner Karoline , Bancher-Todesca Dagmar , Baumgartner-Parzer Sabina , Kautzky-Willer Alexandra
Published: July 2020

Secretagogin (SCGN) is a calcium binding protein related to insulin release in the pancreas. Although SCGN is not co-released with insulin, plasma concentrations have been found to be increased in type 2 diabetes mellitus patients. Until now, no study on SCGN levels in pregnancy or patients with gestational diabetes mellitus (GDM) has been published. In 93 women of a high-risk population for GDM at the Medical University of Vienna, secretagogin levels of 45 GDM patients were compared to 48 women with a normal glucose tolerance (NGT). Glucose tolerance, insulin resistance and secretion were assessed with oral glucose tolerance tests (OGTT) between the 10th and 28th week of gestation (GW) and postpartum. In all women, however, predominantly in women with NGT, there was a significant positive correlation between SCGN levels and Stumvoll first (rp = 0.220, p = 0.032) and second phase index (rp = 0.224, p = 0.028). SCGN levels were not significantly different in women with NGT and GDM. However, SCGN was higher postpartum than during pregnancy (postpartum: 88.07 ± 35.63 pg/mL; pregnancy: 75.24 ± 37.90 pg/mL, p = 0.004). SCGN was directly correlated with week of gestation (rp = 0.308; p = 0.021) and triglycerides (rp = 0.276; p = 0.038) in women with GDM. Therefore, SCGN is related to insulin secretion and hyperinsulinemia during pregnancy; however, it does not display differences between women with NGT and GDM.
Clinical Management of Diabetes Mellitus in the Era of COVID-19: Practical Issues, Peculiarities and Concerns
Authors: Koliaki Chrysi , Tentolouris Anastasios , Eleftheriadou Ioanna , Melidonis Andreas , Dimitriadis George , Tentolouris Nikolaos
Published: July 2020

The management of patients with diabetes mellitus (DM) in the era of the COVID-19 pandemic can be challenging. Even if they are not infected, they are at risk of dysregulated glycemic control due to the restrictive measures which compromise and disrupt healthcare delivery. In the case of infection, people with DM have an increased risk of developing severe complications. The major principles of optimal care for mild outpatient cases include a patient-tailored therapeutic approach, regular glucose monitoring and adherence to medical recommendations regarding lifestyle measures and drug treatment. For critically ill hospitalized patients, tight monitoring of glucose, fluids, electrolytes, pH and blood ketones is of paramount importance to optimize outcomes. All patients with DM do not have an equally increased risk for severity and mortality due to COVID-19. Certain clinical and biological characteristics determine high-risk phenotypes within the DM population and such prognostic markers need to be characterized in future studies. Further research is needed to examine which subgroups of DM patients are expected to benefit the most from specific antiviral, immunomodulatory and other treatment strategies in the context of patient-tailored precision medicine, which emerges as an urgent priority in the era of COVID-19.
Risk-Reducing Gynecological Surgery in Lynch Syndrome: Results of an International Survey from the Prospective Lynch Syndrome Database
Authors: Dominguez-Valentin Mev , Seppälä Toni T. , Engel Christoph , Aretz Stefan , Macrae Finlay , Winship Ingrid , Capella Gabriel , Thomas Huw , Hovig Eivind , Nielsen Maartje , Sijmons Rolf H , Bertario Lucio , Bonanni Bernardo , Tibiletti Maria Grazia , Cavestro Giulia Martina , Mints Miriam , Gluck Nathan , Katz Lior , Heinimann Karl , Vaccaro Carlos A. , Green Kate , Lalloo Fiona , Hill James , Schmiegel Wolff , Vangala Deepak , Perne Claudia , Strauß Hans-Georg , Tecklenburg Johanna , Holinski-Feder Elke , Steinke-Lange Verena , Mecklin Jukka-Pekka , Plazzer John-Paul , Pineda Marta , Navarro Matilde , Vidal Joan Brunet , Kariv Revital , Rosner Guy , Piñero Tamara Alejandra , Gonzalez María Laura , Kalfayan Pablo , Sampson Julian R. , Ryan Neil A. J. , Evans D. Gareth , Møller Pål , Crosbie Emma J.
Published: July 2020

Purpose: To survey risk-reducing hysterectomy and bilateral salpingo-oophorectomy (BSO) practice and advice regarding hormone replacement therapy (HRT) in women with Lynch syndrome. Methods: We conducted a survey in 31 contributing centers from the Prospective Lynch Syndrome Database (PLSD), which incorporates 18 countries worldwide. The survey covered local policies for risk-reducing hysterectomy and BSO in Lynch syndrome, the timing when these measures are offered, the involvement of stakeholders and advice regarding HRT. Results: Risk-reducing hysterectomy and BSO are offered to path_MLH1 and path_MSH2 carriers in 20/21 (95%) contributing centers, to path_MSH6 carriers in 19/21 (91%) and to path_PMS2 carriers in 14/21 (67%). Regarding the involvement of stakeholders, there is global agreement (~90%) that risk-reducing surgery should be offered to women, and that this discussion may involve gynecologists, genetic counselors and/or medical geneticists. Prescription of estrogen-only HRT is offered by 15/21 (71%) centers to women of variable age range (35–55 years). Conclusions: Most centers offer risk-reducing gynecological surgery to carriers of path_MLH1, path_MSH2 and path_MSH6 variants but less so for path_PMS2 carriers. There is wide variation in how, when and to whom this is offered. The Manchester International Consensus Group developed recommendations to harmonize clinical practice across centers, but there is a clear need for more research.
Mother-to-Infant Bonding in Women with Postpartum Psychosis and Severe Postpartum Depression: A Clinical Cohort Study
Authors: Gilden Janneke , Molenaar Nina M. , Smit Anne K. , Hoogendijk Witte J. G. , Rommel Anna-Sophie , Kamperman Astrid M. , Bergink Veerle
Published: July 2020

Mother-to-infant bonding is important for long-term child development. The aim of this study was to investigate bonding in women admitted to a Mother and Baby Unit with postpartum depression (PD, n = 64) and postpartum psychosis (PP, n = 91). Participants completed the Postpartum Bonding Questionnaire (PBQ), the Edinburgh Postnatal Depression Scale (EPDS) and the Young Mania Rating Scale (YMRS) weekly during admission. At admission, 57.1% of women with PD had impaired bonding, compared to only 17.6% of women with PP (p-value < 0.001). At discharge, only 18.2% of women with PD and 5.9% of women with PP still experienced impaired bonding (p-value = 0.02). There was a strong association between decrease of depressive and manic symptoms and improved bonding over an eight-week admission period. In a small group of women (5.7%) impaired bonding persisted despite being in remission of their psychiatric disorder. The results from our study show that impaired bonding is a more present and evidently severe problem in postpartum depression but not so much in postpartum psychosis. Treatment of depressive symptoms will improve bonding in almost all women, but clinicians should assess if impaired bonding is still present after remission because for a small group special care and treatment focused on bonding might be required.
Exercise Training Protects against Atorvastatin-Induced Skeletal Muscle Dysfunction and Mitochondrial Dysfunction in the Skeletal Muscle of Rats
Authors: Seo Dae Yun , Heo Jun-Won , No Mi-Hyun , Yoo Su-Zi , Ko Jeong Rim , Park Dong-Ho , Kang Ju-Hee , Kim Chang-Ju , Jung Su-Jeen , Han Jin , Kwak Hyo-Bum
Published: July 2020

Statins are used to prevent and treat atherosclerotic cardiovascular disease, but they also induce myopathy and mitochondrial dysfunction. Here, we investigated whether exercise training prevents glucose intolerance, muscle impairment, and mitochondrial dysfunction in the skeletal muscles of Wistar rats treated with atorvastatin (5 mg kg−1 day−1) for 12 weeks. The rats were assigned to the following three groups: the control (CON), atorvastatin-treated (ATO), and ATO plus aerobic exercise training groups (ATO+EXE). The ATO+EXE group exhibited higher glucose tolerance and forelimb strength and lower creatine kinase levels than the other groups. Mitochondrial respiratory and Ca2+ retention capacity was significantly lower in the ATO group than in the other groups, but exercise training protected against atorvastatin-induced impairment in both the soleus and white gastrocnemius muscles. The mitochondrial H2O2 emission rate was relatively higher in the ATO group and lower in the ATO+EXE group, in both the soleus and white gastrocnemius muscles, than in the CON group. In the soleus muscle, the Bcl-2, SOD1, SOD2, Akt, and AMPK phosphorylation levels were significantly higher in the ATO+EXE group than in the ATO group. In the white gastrocnemius muscle, the SOD2, Akt, and AMPK phosphorylation levels were significantly higher in the ATO+EXE group than in the ATO group. Therefore, exercise training might regulate atorvastatin-induced muscle damage, muscle fatigue, and mitochondrial dysfunction in the skeletal muscles.
Predictive Value of Serial ECGs in Patients with Suspected Myocardial Infarction
Authors: Lehmacher Jonas , Neumann Johannes Tobias , Sörensen Nils Arne , Goßling Alina , Haller Paul Michael , Hartikainen Tau Sarra , Clemmensen Peter , Zeller Tanja , Blankenberg Stefan , Westermann Dirk
Published: July 2020

The electrocardiogram (ECG) is an important diagnostic tool for patients with suspected acute myocardial infarction (AMI). Current guidelines recommend serial ECGs in case of persisting symptoms. We aimed to analyze the predictive value of ischemic ECG-signs in patients with suspected AMI. Patients presenting to the emergency department with suspected AMI were included. All patients with ST-elevation AMI were excluded from analyses. Patients received 12-lead-ECG and high-sensitive Troponin T (hs-TnT)-measurement at admission and after 3 h. Four groups were defined: no ischemic signs in either ECG; new ischemic signs in the second ECG; resolved ischemic signs in the second ECG; and persistent ischemic signs in both ECGs. Patients were followed for 2 years to assess the composite endpoint of all-cause-mortality, AMI, and coronary revascularization. Using a 30-day landmark analysis, a Cox regression with ischemic signs as the variable of interest, adjusted by cardiovascular risk factors, was calculated. Of 1675 patients, 1321 showed no ischemic signs, in 25 new-, in 92 resolved- and in 237 patients, persistent ischemic signs were documented. Patients with persistent ischemic signs had significantly worse outcomes, compared to those without. Compared to no ischemic signs, adjusted hazard ratios for the combined endpoint were 0.81 (95% CI 0.20, 3.31; p-value = 0.77) for new-, 0.59 (95% CI 0.26, 1.34; p-value = 0.21) for resolved-, and 1.47 (95% CI 1.102, 2.13; p-value = 0.041) for persistent ischemic signs. In patients with suspected AMI, persistent ischemic ECG-signs are predictive of a higher rate of all-cause-mortality, AMI, and revascularization.
Non-Pharmacological Interventions towards Preventing the Triad Osteoporosis-Falls Risk-Hip Fracture, in Population Older than 65. Scoping Review
Authors: Peraza-Delgado Alba , Sánchez-Gómez María Begoña , Gómez-Salgado Juan , Romero-Martín Macarena , Novo-Muñoz Mercedes , Duarte-Clíments Gonzalo
Published: July 2020

Osteoporosis leads to increased risk of falls, and thus an increase in fractures, highlighting here hip fractures, that result in high mortality, functional disability, and high medical expenditure. The aim is to summarise the available evidence on effective non-pharmacological interventions to prevent the triad osteoporosis/falls risk/hip fracture. A scoping review was conducted consulting the Scientific Electronic Library Online (Scielo), National Institute for Health and Care Excellence (NICE), Cumulative Index to Nursing & Allied Health Literature (CINAHL) y PubMed.databases. Inclusion criteria were articles published between 2013 and 2019, in Spanish or English. In addition, publications on a population over 65 years of age covering non-pharmacological interventions aimed at hip fracture prevention for both institutionalised patients in long-stay health centres or hospitals, and patients cared for at home, both dependent and non-dependent, were included. Sixty-six articles were selected and 13 non-pharmacological interventions were identified according to the Nursing Interventions Classification taxonomy, aimed at preventing osteoporosis, falls, and hip fracture. The figures regarding the affected population according to the studies are alarming, reflecting the importance of preventing the triad osteoporosis, falls risk, and hip fracture among the population over 65 years of age. The most effective interventions were focused on increasing Bone Mineral Density through diet, exercise, and falls prevention. As a conclusion, primary prevention should be applied to the entire adult population, with special emphasis on people with osteoporosis.
Predicting the Ultimate Tensile Strength of Friction Stir Welds Using Gaussian Process Regression
Authors: Hartl Roman , Vieltorf Fabian , Benker Maximilian , Zaeh Michael F.
Published: July 2020

In the work described here, Gaussian process regression was applied to predict the ultimate tensile strength of friction stir welds through data evaluation and to therefore avoid destructive testing. For data generation, a total of 54 welding experiments were conducted in the butt joint configuration using the aluminum alloy EN AW-6082-T6. Four tensile samples were taken from each of the 54 experiments and the resulting ultimate tensile strength of the weld seam segment was modeled as a function of the weld’s surface topography. Further models were created for comparison, which received either the process variables or the process parameters to predict the ultimate tensile strength. It was shown that the ultimate tensile strength can be accurately predicted based on the weld’s surface topography. Especially for low welding speeds, the correlation coefficients between the true and the predicted ultimate tensile strength were high. However, overall, even higher correlation coefficients could be achieved when providing the process variables or the process parameters to the model. In conclusion, it was shown that the developed Gaussian process regression model is a powerful approach for replacing destructive testing and for predicting ultimate tensile strength based solely on data that can be collected non-destructively.
On Influence of Mechanical Properties of Gun Propellants on Their Ballistic Characteristics Determined in Closed Vessel Tests
Authors: Trębiński Radosław , Janiszewski Jacek , Leciejewski Zbigniew , Surma Zbigniew , Kamińska Kinga
Published: July 2020

The geometric burning law of gun propellants is widely used in computer codes used for the simulations of the internal ballistics of guns. However, the results of closed vessel tests prove that the burning process of some propellants deviates from the geometric law. Validation of the hypothesis that observed deviations can be attributed to the cracking of propellant grains was the aim of this work. In order to verify the hypothesis, three types of gun propellants were chosen with considerably differing mechanical strengths: a single-base propellant, a double-base propellant, and a composite propellant. The mechanical properties of the gun propellants were tested using a quasi-static compression method with strain rate values of the order of 0.001 s−1 and the Split Hopkinson Pressure Bar technique with the strain rate in the range of 1000–6000 s−1. The mechanical responses of the propellants were assessed on the basis of the true stress–strain curves obtained and from the point of view of the occurrence of cracks in the propellant grains specimens. Moreover, closed vessel tests were performed to determine experimental shape functions for the considered gun propellants. Juxtaposition of the stress‒strain curves with the experimental shape functions proved that the observed deviations from the geometrical burning law can be attributed mainly to the cracking of propellant grains. The results obtained showed that the rheological properties of propellants are important not only from the point of view of logistical issues but also for the properly controlled burning process of propellants during the shot.
Weak Antilocalization Tailor-Made by System Topography in Large Scale Bismuth Antidot Arrays
Authors: Krupinski Michal , Zarzycki Arkadiusz , Zabila Yevhen , Marszałek Marta
Published: July 2020

Using a two-carriers model and the Hikami-Larkin-Nagaoka (HLN) theory, we investigate the influence of large area patterning on magnetotransport properties in bismuth thin films with a thickness of 50 nm. The patterned systems have been produced by means of nanospheres lithography complemented by RF-plasma etching leading to highly ordered antidot arrays with the hexagonal symmetry and a variable antidot size. Simultaneous measurements of transverse and longitudinal magnetoresistance in a broad temperature range provided comprehensive data on transport properties and enabled us to extract the values of charge carrier densities and mobilities. Weak antilocalization signatures observed at low temperatures provided information on spin-orbit scattering length ranging from 20 to 30 nm, elastic scattering length of approx. 60 nm, and strong dependence on temperature phase coherence length. We show that in the absence of antidots the charge carrier transport follow 2-dimensional behavior and the dimensionality for phase-coherent processes changes from two to three dimensions at temperature higher than 10 K. For the antidot arrays, however, a decrease of the power law dephasing exponent is observed which is a sign of the 1D-2D crossover caused by the geometry of the system. This results in changes of scattering events probability and phase coherence lengths depending on the antidot diameters, which opens up opportunity to tailor the magnetotransport characteristics.
New Twin-Roll Cast Al-Li Based Alloys for High-Strength Applications
Authors: Grydin Olexandr , Stolbchenko Mykhailo , Schaper Mirko , Belejová Sára , Králík Rostislav , Bajtošová Lucia , Křivská Barbora , Hájek Michal , Cieslar Miroslav
Published: July 2020

Al-Li based alloys are attractive materials for the aerospace industry. The twin-roll casting of such materials could provide properties not achievable by conventional direct-chill casting and downstream processing methods due to significantly higher solidification rates. An Al-Li-Cu-Mg-Zr alloy was twin-roll cast with the same alloy containing a small addition of Sc. The microstructure of as-cast materials and the influence of Sc on the behavior of the alloy at elevated temperatures were studied by means of light and electron microscopy and by resistivity measurements. A fine-grained structure was formed during twin-roll casting, but several surface and internal defects were found on the strips, which should be suppressed by a further adjustment of the casting conditions. The addition of Sc had a positive effect on grain size uniformity and microstructure stabilization at elevated temperatures, as shown by the precipitation of a fine dispersion of coherent Sc- and Zr-containing precipitates.
LC–MS Lipidomics: Exploiting a Simple High-Throughput Method for the Comprehensive Extraction of Lipids in a Ruminant Fat Dose-Response Study
Authors: Jenkins Benjamin , Ronis Martin , Koulman Albert
Published: July 2020

Typical lipidomics methods incorporate a liquid–liquid extraction with LC–MS quantitation; however, the classic sample extraction methods are not high-throughput and do not perform well at extracting the full range of lipids especially, the relatively polar species (e.g., acyl-carnitines and glycosphingolipids). In this manuscript, we present a novel sample extraction protocol, which produces a single phase supernatant suitable for high-throughput applications that offers greater performance in extracting lipids across the full spectrum of species. We applied this lipidomics pipeline to a ruminant fat dose–response study to initially compare and validate the different extraction protocols but also to investigate complex lipid biomarkers of ruminant fat intake (adjoining onto simple odd chain fatty acid correlations). We have found 100 lipids species with a strong correlation with ruminant fat intake. This novel sample extraction along with the LC–MS pipeline have shown to be sensitive, robust and hugely informative (>450 lipids species semi-quantified): with a sample preparation throughput of over 100 tissue samples per day and an estimated ~1000 biological fluid samples per day. Thus, this work facilitating both the epidemiological involvement of ruminant fat, research into odd chain lipids and also streamlining the field of lipidomics (both by sample preparation methods and data presentation).
Exercise Induced Changes in Salivary and Serum Metabolome in Trained Standardbred, Assessed by 1H-NMR
Authors: Bazzano Marilena , Laghi Luca , Zhu Chenglin , Lotito Enrica , Sgariglia Stefano , Tesei Beniamino , Laus Fulvio
Published: July 2020

In the present study, data related to the metabolomics of saliva and serum in trained standardbred horses are provided for the first time. Metabolomic analysis allows to analyze all the metabolites within selected biofluids, providing a better understanding of biochemistry modifications related to exercise. On the basis of the current advances observed in metabolomic research on human athletes, we aimed to investigate the metabolites’ profile of serum and saliva samples collected from healthy standardbred horses and the relationship with physical exercise. Twelve trained standardbred horses were sampled for blood and saliva before (T0) and immediately after (T1) standardized exercise. Metabolomic analysis of both samples was performed by 1H-NMR spectroscopy. Forty-six metabolites in serum and 62 metabolites in saliva were detected, including alcohols, amino acids, organic acids, carbohydrates and purine derivatives. Twenty-six and 14 metabolites resulted to be significantly changed between T0 and T1 in serum and saliva, respectively. The findings of 2-hydroxyisobutyrate and 3-hydroxybutyrate in serum and GABA in equine saliva, as well as their modifications following exercise, provide new insights about the physiology of exercise in athletic horses. Glycerol might represent a novel biomarker for fitness evaluation in sport horses.
Preliminary Study on Fluidized Bed Chemical Mechanical Polishing (FB-CMP) Process for Stainless Steel 304 (SS304)
Authors: Kim Taekyoung , Lee Hyunseop
Published: July 2020

Fluidized bed machining (FBM) is used for the surface finishing or cleaning of complex 3D machine parts. FBM is a process of injecting air into a chamber to encourage particles into a fluid-like state. Subsequently, FBM involves rotating the specimen at high speed to process the surface of the material. However, owing to the long processing time involved in FBM, there is a limit to its application in various industries. In this paper, we propose a fluidized bed chemical mechanical polishing (FB-CMP) process, wherein the material removal mechanism of chemical mechanical polishing (CMP) is applied to FBM to improve the processing efficiency of FBM. An FB-CMP system was prepared, and preliminary experiments on the chemical solution were conducted using stainless steel 304 (SS304) plates. In the experiment, hydrogen peroxide (H2O2) was used as the oxidant, oxalic acid (C2H2O4) was used as the complexing agent and alumina (Al2O3) was used as the abrasive particle. The material removal rate (MRR) and roughness reduction rate during the FB-CMP of SS304 were dependent on the composition of the chemical solution. The experimental results revealed the highest MRR and roughness reduction rate at 0.33 wt % H2O2 and 0.2 wt % oxalic acid. To stabilize the proposed FB-CMP process, it is necessary to examine the chemical solutions of various materials.
Theoretical Investigation of Near-Infrared Fabry–Pérot Microcavity Graphene/Silicon Schottky Photodetectors Based on Double Silicon on Insulator Substrates
Authors: Casalino Maurizio
Published: July 2020

In this work a new concept of silicon resonant cavity enhanced photodetector working at 1550 nm has been theoretically investigated. The absorption mechanism is based on the internal photoemission effect through a graphene/silicon Schottky junction incorporated into a silicon-based Fabry–Pérot optical microcavity whose input mirror is constituted by a double silicon-on-insulator substrate. As output mirror we have investigated two options: a distributed Bragg reflector constituted by some periods of silicon nitride/hydrogenated amorphous silicon and a metallic gold reflector. In addition, we have investigated and compared two configurations: one where the current is collected in the transverse direction with respect to the direction of the incident light, the other where it is collected in the longitudinal direction. We show that while the former configuration is characterized by a better responsivity, spectral selectivity and noise equivalent power, the latter configuration is superior in terms of bandwidth and responsivity × bandwidth product. Our results show responsivity of 0.24 A/W, bandwidth in GHz regime, noise equivalent power of 0.6 nW/cm√Hz and full with at half maximum of 8.5 nm. The whole structure has been designed to be compatible with silicon technology.
Topology Optimization for FDM Parts Considering the Hybrid Deposition Path Pattern
Authors: Xu Shuzhi , Huang Jiaqi , Liu Jikai , Ma Yongsheng
Published: July 2020

Based on a solid orthotropic material with penalization (SOMP) and a double smoothing and projection (DSP) approach, this work proposes a methodology to find an optimal structure design which takes the hybrid deposition path (HDP) pattern and the anisotropic material properties into consideration. The optimized structure consists of a boundary layer and a substrate. The substrate domain is assumed to be filled with unidirectional zig-zag deposition paths and customized infill patterns, while the boundary is made by the contour offset deposition paths. This HDP is the most commonly employed path pattern for the fused deposition modeling (FDM) process. A critical derivative of the sensitivity analysis is presented in this paper, which ensures the optimality of the final design solutions. The effectiveness of the proposed method is validated through several 2D numerical examples.
Phosphorus Species in Deep-Sea Carbonate Deposits: Implications for Phosphorus Cycling in Cold Seep Environments
Authors: Zhou Junlie , Du Mengran , Li Jiwei , Xu Hengchao , Ta Kaiwen , Chen Shun , Peng Xiaotong
Published: July 2020

Phosphorus (P) is an important nutrient for biological communities in cold seeps. However, our knowledge on the source, species, and cycling of P in cold seep environments is limited. In this study, the concentration, species, and micro to nanometer scale distribution of P in seep carbonates were examined at three deep-sea cold seeps in the South China Sea and East China Sea. The Ca-P accounts for the largest proportion of P—followed by detrital-P, Fe-P, organic-P, and exchangeable-P. The distribution patterns of Ca-P, detrital-P, and organic-P in the seep carbonates differ from one another, as shown by elemental mapping with NanoSIMS and scanning electron microscopy. The covariation of P with Ca and C reveals that Ca-P co-precipitates with Ca-carbonate, which is linked to the process of sulfate-driven anaerobic oxidation of methane. Organic-P is also observed within biofilm-like organic carbon aggregates, revealing the microbial enrichment of P by fluids in the process of anaerobic oxidation of methane. P with a granulated morphology was identified as detrital-P derived from deep sediments. Most importantly, it is evident that Ca-P is positively correlated to the Fe content in all the seep carbonates. This indicates the likelihood that the dissolved P in cold-seep fluids is released primarily from Fe oxides through Fe-driven anaerobic oxidation of methane in deep sediments. These processes associated with different species of P may have significant implications for P geochemical cycling and anaerobic oxidation of methane impelled by Fe and sulfate reduction in cold seep environments.
Investigations of Feldspar-Quartz Raw Materials After Firing: Effect of Various Na2O/K2O Ratio and Synthetic Pigments Addition
Authors: Lewicka Ewa , Trenczek-Zajac Anita
Published: July 2020

Different techniques (chemical analysis, X-ray diffraction, Mössbauer spectroscopy, UV-Vis-NIR spectrophotometry and chromaticity measurements) were used to study the color variation of feldspathic raw materials after firing at 1200 °C. Two varieties of feldspar-quartz grits (with Na2O or K2O prevalence) doped with synthetic pigments (hematite and rutile) were heat-treated in an oxidizing atmosphere. The results obtained indicate that the color of the ceramic body after firing may not only depend on the presence and analytical content of coloring elements (such as iron and titanium), but on their valence state and the chemical characteristics of the melt itself. The prevalence of larger alkali K+ ions over Na+ ions may cause the reduction of the coordination number of iron. This has a significant effect on the length of the Fe–O bond, which in turn influences the capacity for light absorption of a specific wavelength. The results of spectrophotometric measurements showed pronounced disparity between the raw materials and samples doped with coloring oxides. The introduction of synthetic pigments caused clear changes in the spectral dependence of the total absorbance. The absorbance increased in the whole measuring range, in particular in the visible part of the spectrum. Furthermore, a red-shift of the absorption bands towards longer wavelengths attributed to oxygen-metal charge transfer (OMCT) interactions between Fe3+ and O2− ions as well as to d-d transitions within Fe3+ ions was observed.
Characterization of Fatty Acid Composition Underlying Hypothalamic Inflammation in Aged Mice
Authors: Kim Ye Jin , Tu Thai Hien , Yang Sunggu , Kim Jae Kwang , Kim Jae Geun
Published: July 2020

Degenerative diseases, which can develop during aging, are underlined by inflammatory processes. Hypothalamic inflammation triggered by elevation in circulating fatty acid levels is directly coupled to metabolic disorders. The present study aimed to investigate and characterize the hypothalamic inflammation and composition of fatty acids in the hypothalami of aged mice. We verified that inflammation and microglial activation occur in the hypothalami of aged mice by performing quantitative real-time PCR and using immunohistochemistry methods. In addition, we observed increased levels of various saturated fatty acids in the hypothalami of aged mice, whereas no major changes in the levels of circulating fatty acids were detected using gas chromatography with a flame ionization detector. Collectively, our current findings suggest that increases in saturated fatty acid levels are coupled to hypothalamic inflammation and thereby cause perturbations in energy metabolism during the aging process.
Discovery of Novel Tankyrase Inhibitors through Molecular Docking-Based Virtual Screening and Molecular Dynamics Simulation Studies
Authors: Berishvili Vladimir P. , Kuimov Alexander N. , Voronkov Andrew E. , Radchenko Eugene V. , Kumar Pradeep , Choonara Yahya E. , Pillay Viness , Kamal Ahmed , Palyulin Vladimir A.
Published: July 2020

Tankyrase enzymes (TNKS), a core part of the canonical Wnt pathway, are a promising target in the search for potential anti-cancer agents. Although several hundreds of the TNKS inhibitors are currently known, identification of their novel chemotypes attracts considerable interest. In this study, the molecular docking and machine learning-based virtual screening techniques combined with the physico-chemical and ADMET (absorption, distribution, metabolism, excretion, toxicity) profile prediction and molecular dynamics simulations were applied to a subset of the ZINC database containing about 1.7 M commercially available compounds. Out of seven candidate compounds biologically evaluated in vitro for their inhibition of the TNKS2 enzyme using immunochemical assay, two compounds have shown a decent level of inhibitory activity with the IC50 values of less than 10 nM and 10 μM. Relatively simple scores based on molecular docking or MM-PBSA (molecular mechanics, Poisson-Boltzmann, surface area) methods proved unsuitable for predicting the effect of structural modification or for accurate ranking of the compounds based on their binding energies. On the other hand, the molecular dynamics simulations and Free Energy Perturbation (FEP) calculations allowed us to further decipher the structure-activity relationships and retrospectively analyze the docking-based virtual screening performance. This approach can be applied at the subsequent lead optimization stages.
The Coordination Chemistry of Bio-Relevant Ligands and Their Magnesium Complexes
Authors: Case Derek R. , Zubieta Jon , P. Doyle Robert
Published: July 2020

The coordination chemistry of magnesium (Mg2+) was extensively explored. More recently; magnesium; which plays a role in over 80% of metabolic functions and governs over 350 enzymatic processes; is becoming increasingly linked to chronic disease—predominantly due to magnesium deficiency (hypomagnesemia). Supplemental dietary magnesium utilizing biorelevant chelate ligands is a proven method for counteracting hypomagnesemia. However, the coordination chemistry of such bio-relevant magnesium complexes is yet to be extensively explored or elucidated. It is the aim of this review to comprehensively describe what is currently known about common bio-relevant magnesium complexes from the perspective of coordination chemistry.
Influence of Various Model Compounds on the Rheological Properties of Zein-Based Gels
Authors: Gagliardi Agnese , Voci Silvia , Paolino Donatella , Fresta Massimo , Cosco Donato
Published: July 2020

The controlled release of a compound entrapped in a biocompatible formulation is a sought-after goal in modern pharmaceutical technology. Zein is a hydrophobic protein which has several advantageous properties that make it suitable for use as a biocompatible and degradable material under physiological conditions. It is, therefore, proposed for different biomedical and pharmaceutical applications. In particular, due to its gelling properties, it can be used to form a polymeric network able to preserve biomolecules from harsh environments. The current study was designed to investigate the influence of different probes on the rheological properties of gels made up of zein, in order to characterize the systems as a function of the polymer concentration. Four model compounds characterized by different physico-chemical properties were entrapped in zein gels, and different behaviors (viscoelastic or pronounced solid-like characteristics) of the systems were observed. Zein-based gels showed various release profiles of the encapsulated compounds, suggesting that there are different interaction rates between the probes and the polymeric matrix.