bluuebunny/crossref_metadata_2025 huggingface dataset:
Creation of Tool Coatings Based on Titanium Diboride for Highly Efficient Milling of Chromium–Nickel Alloys
Authors: Grigoriev Sergey N. , Volosova Marina A. , Fedorov Sergey V. , Mitrofanov Artem P. , Gurin Vladimir D. , Okunkova Anna A.
Published: September 2024

This paper describes the principles of obtaining wear-resistant coatings based on titanium diboride that are deposited on the cutting tool for use in the machining of chromium–nickel alloys. The spark plasma sintering of samples from the TiB2/Ti powder composition was studied, and the influence of sintering modes on the characteristics of the ceramic targets was analyzed. The regularities of the magnetron sputtering of sintered targets were revealed. The dependences of the physical and mechanical properties of coatings formed on hard alloy substrates on deposition conditions were established. The wear resistance of carbide samples with TiB2-based coatings under friction-sliding conditions and coated carbide ball-end mills in milling Inconel 718 chromium–nickel alloy that is widely used in the industry was assessed.
A Unique Late Presentation of Primary Breast Lymphoma: A Case Report
Authors: Al Awfi Mahmood Mausd , Algheilani Maryam Nasser , Al Shamsi Salma , Al Julandani Nabila Ali , Mahesh Smitha
Published: September 2024

Background: Primary breast lymphoma is a rare entity in that it accounts for less than 1% of breast cancer and 2.2% of extranodal lymphoma. The most common histological type is diffuse B-cell lymphoma. Early stages of the disease have relatively good prognosis. Case Presentation: In this case, we are reporting on a forty-four-year-old lady presenting a large fungating right breast mass that turned out to be a primary breast lymphoma and whose outcome was unfortunate due to late presentation. Conclusions: Despite significant evolvement on treatment of lymphoma, negligence and social stigmatization still have a role in patients’ demise. Efforts toward awareness and anti-stigmatization are of paramount importance.
Comparative Clinical Characteristics of Frail Older Adults in the Emergency Department: Long-Term Care Hospital versus Community Residence
Authors: Choi Yunhyung , Chung Hosub , Lim Jiyeon , Kim Keon , Bae Sungjin , Choi Yoonhee , Lee Donghoon
Published: September 2024

Background/objective: Older patients from long-term care hospitals (LTCHs) presenting to emergency departments (EDs) exhibit a higher prevalence of frailty than those from the community. However, no study has examined frailty in patients from LTCHs in the ED. This study compared frailty in older patients from LTCHs and the community. Methods: We retrospectively analyzed data from the EDs of three university hospitals between 1 August and 31 October 2023, involving 5908 patients (515 from LTCHs and 5393 from the community). The Korean version of the Clinical Frailty Scale (CFS-K) was used to assess individuals aged 65 and older. We compared clinical characteristics, frailty, length of stay (LOS), and diagnosis between patients from LTCHs (LTCH group) and the community (community group). Results: Among ED patients, 55.0% and 35.2% in the LTCH and the community groups, respectively, were frail (p < 0.001). Of these, 71.7% in the LTCH group were hospitalized compared with 53.1% in the community group (p = 0.001). The odds ratio for in-hospital mortality was 4.910 (95% CI 1.458–16.534, p = 0.010) for frail LTCH patients and 3.748 (95% CI 2.599–5.405, p < 0.001) for frail community patients, compared to non-frail patients. Conclusions: Patients from LTCHs with frailty had higher hospital admission rates and increased in-hospital mortality compared to those in the community at the same frailty level. This study offers essential insights into the characteristics of older patients in LTCHs for healthcare administrators and medical staff worldwide.
Is There Gender Disparity in Vascular Access for Hemodialysis with New Percutaneous Systems? A Systematic Review
Authors: Vergara-Pérez Hugo , Pérez Alba Alejandro , Baliño Pablo , Rius Peris Asunción , Reque Javier
Published: September 2024

Background: Historically, a large gender-related disparity in vascular access (VA) has been demonstrated, with there being a lower prevalence of women with arteriovenous fistula (AVF) compared to men, and women have worse maturity rates. The cause of this difference is not entirely clear, although several reasons that could contribute to it have been hypothesized. The emergence of new percutaneous FAV (pFAV) systems could be an alternative for reducing these differences. Objective: This study aims to determine whether there is a gender difference in the creation of AVFs using new percutaneous systems. Material and Methods: A systematic review of the literature was conducted by searching PubMed and Google Scholar using the following terms: “percutaneous arteriovenous fistula”, “endovascular arteriovenous fistula”, and “hemodialysis”. All clinical trials, comparative studies, and descriptive studies involving patients who underwent a pAVF were included. Results: Finally, the review includes 19 studies, comprising 14 retrospective studies and 5 prospective studies. Of these, six studies are comparative, five of which compare pAVFs with surgically created AVFs (sAVFs), and one compares pAVFs performed using different systems with each other. A total of 1269 patients were included in the review. Of the total number of patients, only 414 were women, representing 32.62% of patients. Conclusions: The number of women included in the various studies analyzing pAVF remains very low, representing less than one-third of all patients. Although the causes of this difference are not entirely clear, several reasons have been hypothesized, such as socioeconomic factors, anatomical factors, or even patients’ preferences. Given these results, further studies are needed to try to clarify the reasons for this gender disparity and to establish different strategies to mitigate the barriers faced by women in accessing AVFs.
Probabilistic Uncertainty Consideration in Regionalization and Prediction of Groundwater Nitrate Concentration
Authors: Karimanzira Divas
Published: September 2024

In this study, we extend our previous work on a two-dimensional convolutional neural network (2DCNN) for spatial prediction of groundwater nitrate, focusing on improving uncertainty quantification. Our enhanced model incorporates a fully probabilistic Bayesian framework and a structure aimed at optimizing both specific value predictions and predictive intervals (PIs). We implemented the Prediction Interval Validation and Estimation Network based on Quality Definition (2DCNN-QD) to refine the accuracy of probabilistic predictions and reduce the width of the prediction intervals. Applied to a model region in Germany, our results demonstrate an 18% improvement in the prediction interval width. While traditional Bayesian CNN models may yield broader prediction intervals to adequately capture uncertainties, the 2DCNN-QD method prioritizes quality-driven interval optimization, resulting in narrower prediction intervals without sacrificing coverage probability. Notably, this approach is nonparametric, allowing it to be effectively utilized across a range of real-world scenarios.
Habitat Suitability Assessment for Two Burrowing Rodents on the Island of Lesvos: A Niche-Based Approach
Authors: Zannetos Stylianos P. , Theodorou Konstantinos , Zevgolis Yiannis G. , Galinou Eleni , Akriotis Triantaphyllos
Published: September 2024

We conducted a habitat suitability assessment for two burrowing rodents, Anatolian or Nehring’s blind mole rat (Nannospalax xanthodon) and Harting’s vole (Microtus hartingi), on the island of Lesvos using a niche-based approach. We collected data on the presence of the two species across the island and selected several environmental variables, including land cover, geology, and habitat topography, to assess their influence on habitat suitability. We used the Maxent species distribution modelling algorithm to predict suitable habitats. The results showed that both species preferred habitats with low slopes and specific geological substrates, i.e., alluvial deposits and volcanic rocks. M. hartingi showed a preference for open habitats such as saltmarshes and non-irrigated arable land, while N. xanthodon preferred non-irrigated arable land, pastures, and discontinuous urban fabric. The model predicted a wider area of suitable habitats for Microtus hartingi compared to N. xanthodon. Interestingly, the two species are absent from the southeastern part of the island despite our model predicting high suitability; this indicates that a natural barrier of hilly terrain, extensive pine forests, and limestone rock formations may exist that impedes dispersal. Our study provides valuable insights into the habitat preferences of these two burrowing rodents on the island of Lesvos, which can inform biodiversity conservation and ecosystem management strategies.
On-Demand Warehousing Platforms: Evolution and Trend Analysis of an Industrial Sharing Economy Model
Authors: Elia Valerio , Gnoni Maria Grazia , Tornese Fabiana
Published: September 2024

Background: The on-demand warehousing (ODW) model is emerging as a platform-enabled logistics solution based on resource sharing for businesses needing storage space. It is based on a business-to-business marketplace where companies can provide (or request) storage services with an elevated level of flexibility. The literature focusing on this topic is still scarce, and while the potential advantages of such a model seem quite clear, challenges and criticalities need to be further explored. Methods: Starting from a state-of-the-art analysis of ODW, a two-step methodology was adopted: first, a SWOT analysis was conducted to help summarize the challenges related to this emerging model. Then, an exploratory analysis of multiple case studies was employed to provide a first discussion on the advantages and criticalities of this model, highlighting its latest evolution. Results: The ODW model is still evolving, as several former pure ODW platforms have been changing their business model to become on-demand 4PLs (defined as “mixed ODW-4PLs”), adapting their core activities to manage the criticalities of on-demand services. Conclusions: This study represents the first attempt to investigate benefits and criticalities of ODW models, outlining the latest trend of ODW and identifying two distinct types of ODW model currently present on the market.
Surface Integrity of Austenitic Manganese Alloys Hard Layers after Cavitation Erosion
Authors: Mitelea Ion , Bordeașu Ilare , Mutașcu Daniel , Crăciunescu Corneliu Marius , Uțu Ion Dragoș
Published: September 2024

Cavitation erosion, as a mechanical effect of destruction, constitutes a complex and critical problem that affects the safety and efficiency of the functioning of engineering components specific to many fields of work, the most well-known being propellers of ships and maritime and river vessels, seawater desalination systems, offshore oil and gas drilling platforms (including drilling and processing equipment), and the rotors and blades of hydraulic machines. The main objective of the research conducted in this paper is to experimentally investigate the phenomenology of this surface degradation process of maritime ships and offshore installations operating in marine and river waters. To reduce cavitation erosion of maritime structures made from Duplex stainless steels, the study used the deposition by welding of layers of metallic alloys with a high capacity for work hardening. The cavitation tests were conducted in accordance with the American Society for Testing and Materials standards. The response of the deposited metal under each coating condition, compared to the base metal, was investigated by calculating the erosion penetration rate (MDER) through mass loss measurements over the cavitation duration and studying the degraded zones using scanning electron microscopy (SEM), the energy-dispersive X-ray analysis, and hardness measurements. It was revealed that welding hardfacing with austenitic manganese alloy contributes to an approximately 8.5–10.5-fold increase in cavitation erosion resistance. The explanation is given by the increase in surface hardness of the coated area, with 2–3 layers of deposited alloy reaching values of 465–490 HV5, significantly exceeding those specific to the base metal, which range from 260–280 HV5. The obtained results highlighted the feasibility of forming hard coatings on Duplex stainless-steel substrates.
2-Methylpropan-2-ammonium [(3R,5R)-7-[(1S,2S,6S,8S,8aR)-6-hydroxy-2-methyl-8-[(2S)-2-methylbutanoyl]oxy-1,2,6,7,8,8a-hexahydronaphthalen-1-yl]-3,5-heptanoate
Authors: Grosu Ioana-Georgeta , Turza Alexandru , Filip Xenia , Miclaus Maria-Olimpia
Published: September 2024

Pravastatin is a popular statin agent with applications in the treatment of cardiovascular diseases for patients with an abnormal lipid panel. The starting form of pravastatin is amorphous and following recrystallization, it becomes a crystalline solid with tert-butylamine salt molecules embedded within the lattice. Its molecular and crystal structure were elucidated based on single-crystal X-ray diffraction and characterized by ss-NMR.
Hydration and Mechanical Properties of High-Volume Fly Ash Cement under Different Curing Temperatures
Authors: Choi Young-Cheol
Published: September 2024

This study aimed to investigate the effects of different curing temperatures on the hydration and mechanical properties of high-volume fly ash (HVFA) concrete. The key variables were curing temperature (13 °C, 23 °C, 43 °C) and fly ash (FA) content (0%, 35%, 55%). The hydration characteristics of HVFA cement were examined by evaluating the setting time and heat of hydration under different curing temperatures. The mechanical properties of HVFA concrete were analyzed by preparing concrete specimens at various curing temperatures and measuring the compressive strength at 7, 28, 56, and 91 days. The results indicated that concrete with high FA content was more sensitive to curing temperature compared to ordinary Portland cement.
Investigation of Phase Transformation and Fracture Pattern as a Result of Long-Term Chewing Simulation and Static Loading of Reduced-Diameter Zirconia Implants
Authors: Atalay Seçkiner Pelin , Gönüldaş Fehmi , Akat Bora , Buyuksungur Arda , Orhan Kaan
Published: September 2024

While zirconia implants exhibit osseointegration comparable to that of titanium, concerns arise regarding low-temperature degradation and its potential impact on fracture strength. This study investigated the phase transformation and fracture characteristics of zirconia dental implants after aging through chewing simulation and subsequent static loading. The experimental setup involved 48 one-piece monobloc zirconia implants with diameters of 3.0 mm and 3.7 mm that had straight or angled abutments, with crown restorations, which were divided into six groups based on intraoral regions. The specimens underwent chewing simulation equal to five years of oral service, which was followed by static loading. Statistical analyses were performed for the data obtained from the tests. After dynamic and static loadings, the fractured samples were investigated by Raman spectroscopy to analyze the phase composition and micro-CT to evaluate fracture surfaces and volume changes. According to the results, narrow-diameter zirconia implants have low mechanical durability. The fracture levels, fracture patterns, total porosity, and implant fracture volume values varied according to the implant diameter and phase transformation grade. It was concluded that phase transformation initially guides the propagation of microcracks in zirconia implants, enhancing fracture toughness up to a specific threshold; however, beyond that point, it leads to destructive consequences.
Investigation on the Performances of Esterified Waste Cooking Oil Rejuvenator and Recycled Asphalt
Authors: Wang Junhui , Ye Qunshan , Fan Lingyi , Xie Cheng , Liu Haobin
Published: September 2024

Waste cooking oil (WCO) recycled asphalt is facing issues regarding insufficient thermal oxidation stability and aging resistance. In this research, glycerol esterification was adopted to pretreat WCO, and the consequences of this treatment on the aging resistance and thermal stability of WCO were analyzed. The impacts of varying levels of esterification of WCO on the high-temperature, low-temperature performances, fatigue properties, and aging resistance of recycled asphalt were investigated. Furthermore, the mechanisms of regeneration and the anti-aging of deeply esterified WCO recycled asphalt were revealed by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) tests. The results indicated that variations in the physical properties of WCO during the aging process were reduced, and its aging resistance was improved following glycerol esterification therapy. The initial thermal decomposition temperature was increased by approximately 115 °C, which resulted in the enhancement of thermal stability significantly. Recycled asphalt obtained from deeply esterified WCO exhibited superior high-temperature, low-temperature performances, and fatigue properties. Moreover, the thermal oxidation stability and aging resistance of recycled asphalt with deep-esterified WCO could be promoted by reducing the oxidation and volatilization of light components during the aging process, with the complex modulus ageing resistance index decreasing by 13.27% and the phase angle ageing resistance index increasing by 14.71%.
Evolution of Atomic-Level Interfacial Fracture Mechanics in Magnesium–Zinc Compounds Used for Bioresorbable Vascular Stents
Authors: Zhou Zhen , Ji Chaoyue , Hou Dongyang , Jiang Shunyong , Ouyang Yuhang , Dong Fang , Liu Sheng
Published: September 2024

Bioresorbable magnesium-metal vascular stents are gaining popularity due to their biodegradable nature and good biological and mechanical properties. They are also suitable candidate materials for biodegradable stents. Due to the rapid degradation rate of Mg metal vascular scaffolds, a Mg/Zn bilayer composite was formed by a number of means, such as magnetron sputtering and physical vapor deposition, thus delaying the degradation time of the Mg metal vascular scaffolds while providing good radial support for the stenotic vessels. However, the interlaminar compounds at the metal interface have an essential impact on the mechanical properties of the bi-material interface, especially the cracking and delamination of the Mg matrix Zn coating vascular stent in the radially expanded process layer. Intermetallic compounds (IMCs) are commonly found in dual-layer composites, such as Mg/Zn composites and multi-layer structures. They are frequently overlooked in simulations aiming to predict mechanical properties. This paper analyses the interfacial failure processes and evolutionary mechanisms of interfacial fracture mechanics of a Mg/Zn interface with an intermetallic compound layer between coated Zn and Mg matrix metallic vascular stents. The simulation results show that the fracture mode in the Mg/Zn interface with an intermetallic compound involves typical ductile fracture under static tensile conditions. The dislocation line defects mainly occur on the side of the Mg, which induces the Mg/Zn interfacial crack to expand along the interface into the pure Mg. The stress intensity factor and the critical strain energy release rate decrease as the intermetallic compound layer’s thickness gradually increases, indicating that the intensity of stress and the force of the crack extending and expanding along the crack tip are weakened. The presence of intermetallic compounds at the interface can significantly strengthen the mechanical properties of the material interface and alleviate the crack propagation between the interfaces.
Characteristics of Differential Entropy Generation in a Transonic Rotor and Its Applications to Casing Treatment Designs
Authors: Ma Jingyuan , Wang Yongsheng , Lin Feng
Published: September 2024

Casing treatments improve compressor stability but often at the expense of compressor efficiency. In this study, the differential entropy generation rate (DEGR) was applied to both efficiency evaluation and stall margin estimation. Rotor 67 was used as the compressor in this study and the simulation results were analyzed to correlate the distribution of the DEGR with the flow structures in the rotor at three rotating speeds. The characteristics of the DEGR at each speed were analyzed, exhibiting the characteristics of the flow structures at peak efficiency (PE) and near stall (NS) flow conditions. Loss analysis was conducted on the peak efficiency operating condition, particularly at 100% rotating speed. The critical state of the DEGR was investigated to identify stall occurrences on the near-stall condition. It was thus concluded that the DEGR can be a unified measure of both efficiency and stall margin. This theoretical exploration was subsequently applied to the design of casing treatments with two objectives: enhancing peak efficiency at 100% rotating speed and improving stability margins at all speeds. Two casing treatments were designed, with two circumferential grooves positioned axially at different locations. Their mechanisms for reducing the high DEGR area in the peak efficiency condition of 100% speed and suppressing an increase in DEGR during approaching stall were investigated, respectively. The results indicated that the presence of a groove near the leading edge of the blade tip can effectively suppress stall at all speeds. In order to achieve peak efficiency at high speeds, the extent of casing treatment coverage above the shock wave plays a crucial role in minimizing losses.
Latent Space Perspicacity and Interpretation Enhancement (LS-PIE) Framework
Authors: Stevens Jesse , Wilke Daniel N. , Setshedi Isaac I.
Published: September 2024

Linear latent variable models such as principal component analysis (PCA), independent component analysis (ICA), canonical correlation analysis (CCA), and factor analysis (FA) identify latent directions (or loadings) either ordered or unordered. These data are then projected onto the latent directions to obtain their projected representations (or scores). For example, PCA solvers usually rank principal directions by explaining the most variance to the least variance. In contrast, ICA solvers usually return independent directions unordered and often with single sources spread across multiple directions as multiple sub-sources, severely diminishing their usability and interpretability. This paper proposes a general framework to enhance latent space representations to improve the interpretability of linear latent spaces. Although the concepts in this paper are programming language agnostic, the framework is written in Python. This framework simplifies the process of clustering and ranking of latent vectors to enhance latent information per latent vector and the interpretation of latent vectors. Several innovative enhancements are incorporated, including latent ranking (LR), latent scaling (LS), latent clustering (LC), and latent condensing (LCON). LR ranks latent directions according to a specified scalar metric. LS scales latent directions according to a specified metric. LC automatically clusters latent directions into a specified number of clusters. Lastly, LCON automatically determines the appropriate number of clusters to condense the latent directions for a given metric to enable optimal latent discovery. Additional functionality of the framework includes single-channel and multi-channel data sources and data pre-processing strategies such as Hankelisation to seamlessly expand the applicability of linear latent variable models (LLVMs) to a wider variety of data. The effectiveness of LR, LS, LC, and LCON is shown in two foundational problems crafted with two applied latent variable models, namely, PCA and ICA.
Therapeutic Effect of Decellularized Extracellular Matrix from Fish Skin for Accelerating Skin Regeneration
Authors: Heo Seong-Yeong , Kim Tae-Hee , Kim Se-Chang , Oh Gun-Woo , Heo Soo-Jin , Jung Won-Kyo
Published: September 2024

A cellular matrix derived from natural tissue functions as a highly biocompatible and versatile material for wound healing application. It provides a complex and highly organized environment with biological molecules and physical stimuli. Recently, various kinds of tissue/organ decellularized extracellular matrixes (dECMs) from bovine and porcine have been used as biomedical applications to support tissue regeneration but inherit religious restrictions and the risk of disease transmission to humans. Marine fish-derived dECMs are seen as attractive alternatives due to their similarity to mammalian physiology, reduced biological risks, and fewer religious restrictions. The aim of this study was to derive a decellularized matrix from the olive flounder (Paralichthys olivaceus) skin and evaluate its suitability as a wound healing application. Olive flounder skin was treated with a series of chemical treatments to remove cellular components. Decellularized fish skin (dFS) was confirmed to be successful in decellularization by evaluating the DNA content (2.84%). The dFS was characterized and evaluated in vivo to assess its biological activities. The mouse wound defect model was used to evaluate the in vivo performance of the dFS compared with that of the decellularized porcine skin (dPS). The resultant dFS was shown to enhance wound healing compared with the no-treatment group and dPS. This study suggests that dFS has potential for skin regeneration application.
Optimal Targeted Temperature Management for Patients with Post-Cardiac Arrest Syndrome
Authors: Yagi Tsukasa , Tachibana Eizo , Atsumi Wataru , Kuronuma Keiichiro , Iso Kazuki , Hayashida Satoshi , Sugai Shonosuke , Sasa Yusuke , Shoji Yoshikuni , Kunimoto Satoshi , Tani Shigemasa , Matsumoto Naoya , Okumura Yasuo
Published: September 2024

Background: To prevent hypoxic–ischemic brain damage in patients with post-cardiac arrest syndrome (PCAS), international guidelines have emphasized performing targeted temperature management (TTM). However, the most optimal targeted core temperature and cooling duration reached no consensus to date. This study aimed to clarify the optimal targeted core temperature and cooling duration, selected according to the time interval from collapse to return of spontaneous circulation (ROSC) in patients with PCAS due to cardiac etiology. Methods: Between 2014 and 2020, the targeted core temperature was 34 °C or 35 °C, and the cooling duration was 24 h. If the time interval from collapse to ROSC was within 20 min, we performed the 35 °C targeted core temperature (Group A), and, if not, we performed the 34 °C targeted core temperature (Group B). Between 2009 and 2013, the targeted core temperature was 34 °C, and the cooling duration was 24 or 48 h. If the interval was within 20 min, we performed the 24 h cooling duration (Group C), and, if not, we performed the 48 h cooling duration (Group D). Results: The favorable neurological outcome rates at 30 days following cardiac arrest were 45.7% and 45.5% in Groups A + B and C + D, respectively (p = 0.977). In patients with ROSC within 20 min, the favorable neurological outcome rates at 30 days following cardiac arrest were 75.6% and 86.4% in Groups A and C, respectively (p = 0.315). In patients with ROSC ≥ 21 min, the favorable neurological outcome rates at 30 days following cardiac arrest were 29.3% and 18.2% in Groups B and D, respectively (p = 0.233). Conclusions: Selecting the optimal target core temperature and the cooling duration for TTM, according to the time interval from collapse to ROSC, may be helpful in patients with PCAS due to cardiac etiology.
Anesthesiological Preoperative Interview with a Palliative Care Patient: A Simulation-Based Experiment Using Standardized Patients
Authors: Lassen Christoph L. , Jaschinsky Fabian , Stamouli Elena , Lindenberg Nicole , Wiese Christoph H. R.
Published: September 2024

Background and Objectives: Anesthesiologists come into contact with patients under palliative care in different clinical settings. They also routinely encounter these patients in their primary field of work, the operating room. Patients receiving palliative care who are scheduled for surgery will pose unique challenges in perioperative management, often presenting with advanced disease and with different psychosocial and ethical issues. This study aims to evaluate whether anesthesiologists without specialty training in palliative medicine will spot perioperative challenges presented by patients under palliative care and address them adequately. Materials and Methods: In this study, we simulated a preoperative anesthesiological interview using standardized patients and anesthesiologists (specialists as well as trainees). The standardized patients were asked to represent a patient under palliative care in need of surgery because of a mechanical ileus. We conducted 32 interviews, dividing the anesthesiologists into two groups. In one group, the standardized patients were instructed to address four problems, i.e., use of a port catheter for anesthesia, nausea and vomiting, pain medication, and an advance directive including a limitation of treatment (DNR-order). In the other group, these problems were also present, but were not actively addressed by the standardized patients if not asked for. The interviews were recorded, transcribed, and then analyzed. Results: In most cases, the medical problems were spontaneously identified and discussed. In only a few cases, however, was a therapy recommendation made for improved symptom control. The advance directive was spontaneously discussed by only 3 of the 32 (9%) anesthesiologists. In another 16 cases, the advance directive was discussed at the request of the standardized patients. The limitation of treatment stayed in place in all cases, and the discussion of the advance directives remained short, with an average duration of just over 5 min. Conclusions: In this study, the complex problems of patients under palliative care are not sufficiently taken into account in a preoperative anesthesiological interview. To improve treatment of the medical problems, therapists who have palliative medicine expertise, should be involved in the perioperative medical care, ideally as a multi-professional team. The discussion about perioperative limitations of treatment should be held beforehand, for example, as part of a structured advanced care planning discussion.
Dose-Dependent Induction of Differential Seizure Phenotypes by Pilocarpine in Rats: Considerations for Translational Potential
Authors: Vasović Dolika , Stanojlović Olivera , Hrnčić Dragan , Šutulović Nikola , Vesković Milena , Ristić Aleksandar J. , Radunović Nebojša , Mladenović Dušan
Published: September 2024

Background and Objectives: Pilocarpine is used in experimental studies for testing antiepileptic drugs, but further characterization of this model is essential for its usage in testing novel drugs. The aim of our study was to study the behavioral and EEG characteristics of acute seizures caused by different doses of pilocarpine in rats. Materials and Methods: Male Wistar rats were treated with a single intraperitoneal dose of 100 mg/kg (P100), 200 mg/kg (P200), or 300 mg/kg (P300) of pilocarpine, and epileptiform behavior and EEG changes followed within 4 h. Results: The intensity and the duration of seizures were significantly higher in P300 vs. the P200 and P100 groups, with status epilepticus dominating in P300 and self-limiting tonic–clonic seizures in the P200 group. The seizure grade was significantly higher in P200 vs. the P100 group only during the first hour after pilocarpine application. The latency of seizures was significantly shorter in P300 and P200 compared with P100 group. Conclusions: Pilocarpine (200 mg/kg) can be used as a suitable model for the initial screening of potential anti-seizure medications, while at a dose of 300 mg/kg, it can be used for study of the mechanisms of epileptogenesis.
GBT1118, a Voxelotor Analog, Ameliorates Hepatopathy in Sickle Cell Disease
Authors: Haroun Elio , Lim Seah H. , Dutta Dibyendu
Published: September 2024

Background and Objectives: In sickle cell disease (SCD), hepatopathy is a cumulative consequence of ischemia/reperfusion (I/R) injury from a vaso-occlusive crisis, tissue inflammation, and iron overload due to blood transfusion. Hepatopathy is a major contributing factor of shortened life span in SCD patients. We hypothesized that the voxelotor, a hemoglobin allosteric modifier, ameliorates sickle hepatopathy. Materials and Methods: Townes SCD mice and their controls were treated with either chow containing GBT1118, a voxelotor analog, or normal chow. We evaluated inflammation, fibrosis, apoptosis and ferroptosis in their livers using qPCR, ELISA, histology, and immunohistochemistry. Results: GBT1118 treatment resulted in reduced hemolysis, iron overload and inflammation in the liver of SCD mice. There were significant reductions in the liver enzyme levels and bile acids. Furthermore, GBT1118-treated mice exhibited reduced apoptosis, necrosis, and fibrosis. Increased ferroptosis as evident from elevated 4-hydroxynonenal (4-HNE) staining, malondialdehyde (MDA) levels, and expression of Ptgs2 and Slc7a11 mRNAs, were also significantly reduced after GBT1118 treatment. To explain the increased ferroptosis, we evaluated iron homeostasis markers in livers. SCD mice showed decreased expression of heme oxygenase-1, ferritin, hepcidin, and ferroportin mRNA levels. GBT1118 treatment significantly increased expressions of these genes. Conclusions: Our results suggest GBT1118 treatment in SCD confers the amelioration of sickle hepatopathy by reducing inflammation, fibrosis, apoptosis, iron overload and ferroptosis.
Microstructure and Characteristics of the Welded Joint between Ni-Cr Alloys and Copper
Authors: Zhang Jingang , Zhang Wanpeng , Yu Xiaoquan , Xie Hang , Zhou Chao , Song Hongbing , Huang Jiankang
Published: September 2024

In the field of petroleum extraction, the welding technology of the core wire (the hybrid structure of copper and the Ni-Cr alloy) in high-power oilfield heaters is a key process that determines the efficiency of the heater. Using the tungsten inert gas (TIG) welding method of filling pure copper wire, this work effectively joins the dissimilar metals of red copper and the Cr20Ni80 nickel–chromium alloy. The microstructure, mechanical properties, and conductivity of the joint were analyzed. The results showed that the surface of the welded dissimilar metal joint was smooth and uniform; radiographic nondestructive testing did not reveal any macroscopic forming defects such as pores or cracks. The microstructure of the joint fusion zone exhibits an equiaxed grain morphology. The interface between the copper and the fusion zone displays a columnar grain structure, growing perpendicular to the fusion line. An interdiffusion layer of elements was formed at the interface between the Ni-Cr alloy and the fusion zone. The microhardness of the joint shows a stepwise decreasing trend, with the highest hardness on the nickel–chromium alloy side, followed by the fusion zone, and the lowest on the copper side. The joint fractures at the copper base material, with a tensile strength greater than 220 MPa, indicating a ductile fracture mode. During the electrical heating process, the joint temperature does not significantly increase compared to the copper side, demonstrating good thermal stability.
Precision Electrochemical Micro-Machining of Molybdenum in Neutral Salt Solution Based on Electrochemical Analysis
Authors: Wu Yuqi , Wang Guoqian , Yang Moucun , Zhang Yan
Published: September 2024

Molybdenum is an important material in modern industry, widely used in extreme environments such as rocket engine nozzles and microelectrodes due to its high melting point, excellent mechanical properties, and thermal conductivity. However, as a difficult-to-machine metal, traditional machining methods struggle to achieve the desired microstructures in molybdenum. Electrochemical machining (ECM) offers unique advantages in manufacturing fine structures from hard-to-machine metals. Studies have shown that molybdenum exhibits a fast corrosion rate in alkaline or acidic solutions, posing significant environmental pressure. Therefore, this study investigates the electrochemical machining of molybdenum in neutral salt solutions to achieve high-precision microstructure fabrication. First, the polarization curves and electrochemical impedance spectroscopy (EIS) of molybdenum in NaNO3 solutions of varying concentrations were measured to determine its electrochemical reaction characteristics. The results demonstrate that molybdenum exhibits good electrochemical reactivity in NaNO3 solutions, leading to favorable surface erosion morphology. Subsequently, a mask electrochemical machining technique was employed to fabricate arrayed microstructures on the molybdenum surface. To minimize interference between factors, an orthogonal experiment was used to optimize the parameter combination, determining the optimal machining process parameters. Under these optimal conditions, an array of micro-groove structures was successfully fabricated with an average groove width of 110 μm, a depth-to-width ratio of 0.21, an aspect ratio of 9000, and a groove width error of less than 5 μm.
A Highly Linear Ultra-Low-Area-and-Power CMOS Voltage-Controlled Oscillator for Autonomous Microsystems
Authors: Pacheco Javier de Mena , Palacios Tomas , Hempel Marek , Vallejo Marisa Lopez
Published: September 2024

Voltage-controlled oscillators (VCOs) can be an excellent means of converting a magnitude into a readable value. However, their design becomes a real challenge for power-and-area-constrained applications, especially when a linear response is required. This paper presents a VCO for smart dust systems fabricated by 65 nm technology. It is designed to minimize leakage, limit high peak currents and provide an output whose frequency variation is linear with the input voltage, while allowing rail-to-rail input range swing. The oscillator occupies 592 μm2, operates in a frequency range from 43 to 53 Hz and consumes a maximum average power of 210 pW at a supply voltage of 1 V and 4 pW at 0.3 V. In addition, the proposed VCO exhibits a quasi-linear response of frequency vs. supply voltage and temperature, allowing easy temperature compensation with complementary to absolute temperature (CTAT) voltage.
Geological Controlling Factors on Mississippi Valley-Type Pb-Zn Mineralization in Western Semnan, Iran
Authors: Qaderi Soran , Maghsoudi Abbas , Pour Amin Beiranvand , Yousefi Mahyar
Published: September 2024

Mississippi Valley-type (MVT) Pb-Zn deposits are a subtype of sedimentary-hosted mineralization. These deposits are hosted by carbonate sequences in passive-margin tectonic settings. This paper uses the Fry technique and distance distribution analysis to model the spatial distribution pattern of MVT Pb-Zn deposits in the west of Semnan province (Iran) and their association with some geological features, aiming at mapping mineral prospectivity in the area. The modeling results reveal that NE–SW trending faults and Permian-Cretaceous dolomites and limestone are, respectively, major structural and lithological controlling factors of mineralization that operate as conduits and physicochemical subsystems of ore formation. The integration of the corresponding evidence maps of the controlling factors with a model of the geochemical signature of MVT Pb-Zn deposits through a supervised random forest approach, a machine learning technique, gains an exceptional prospectivity map predicting 100% of the known MVT Pb-Zn deposits in only 15% of the study area, which is an achievement. The recognized targets can be planned for further exploration.
Test Method for Mineral Spatial Distribution of BIF Ore by Imaging Spectrometer
Authors: Yi Wenhua , Liu Shanjun , Ding Ruibo , Yue Heng , Wang Haoran , Wang Jingli
Published: September 2024

The spatial distribution characteristics of iron ore components are important when measuring the difficulty of their beneficiation. Polarized light microscopy and scanning electron microscopy are traditional methods with some shortcomings, including complicated operation and low efficiency. Most of the laboratory hyperspectral imaging techniques that have emerged in recent years have been focused on the field of mineral resource exploration. In contrast, the mineral distribution and tectonic characteristics of iron ores have been relatively poorly studied in the field of beneficiation. To address the issue, 11 experimental samples of banded iron formation (BIF)-hosted iron ores were selected and tested using an imaging spectrometer. Then, based on the differences in spectral characteristic of the three main components (quartz, hematite, and magnetite) in the samples, the identification model of the spatial distribution of the iron ore components was established using the normalized spectral amplitude index (NSAI) and spectral angle mapper (SAM). The NSAI and SAM identify minerals based on spectral amplitude features and spectral morphological features of the sample, respectively. The spatial distribution of different minerals in the samples was tested using the model, and the test results demonstrated that the spatial distribution of the three components is consistent with the banded tectonic character of the sample. Upon comparison with the chemical test results, the mean absolute errors (MAE) of the model for quartz, hematite, and magnetite in the samples were 2.03%, 1.34%, and 1.55%, respectively, and the root mean square errors (RMSE) were 2.72%, 2.08%, and 1.85%, respectively, with the exception of one martite sample that reached an MAE of 10.17%. Therefore, the model demonstrates a high degree of accuracy. The research provides a new method to test the spatial distribution of iron ore components.
The Rise of Proterozoic Diagenetic Spheroids Formed by Chemically Oscillating Reactions and Stimulated by Environmental Redox Changes
Authors: Buma-at Princess Aira , Papineau Dominic
Published: September 2024

Diagenetic spheroids are rounded mineralised structures in sedimentary rocks that span several orders of size dimensions. These objects include rosettes spanning tens of micrometres; millimetre-sized granules; and centimetre- to metre-scale botryoids, nodules, and concretions. Connections between diagenetic spheroids and chemically oscillating reactions (COR) have been established based on chemical and pattern similarities. Nevertheless, it is unknown if there are variations in their occurrences throughout geological time, especially during periods of global environmental change. This is because COR are pattern-forming reactions where carboxylic acids are decarboxylated by strong oxidants like sulphuric acid, bromate, or iodate. The hypothesis is that there should be a greater number of diagenetic spheroids at periods of increased atmospheric and oceanic oxygenation levels. Hence, this work presents the first compilation of occurrences of diagenetic spheroids between 0.541 and 1.8 billion years ago (Ga). The compiled patterned objects are those with concentric laminations and radially aligned crystals, which are patterns akin to equidistant circularly concentric waves that radially diffuse in COR. Another characteristic of diagenetic spheroids, similar to that found in botryoidal minerals, is the destructive interference that forms circular twins; this is identical to the COR pattern formed when circular waves meet. The timeline of Proterozoic diagenetic spheroids produced in this work reveals a significant increase in occurrences across the Ediacaran, which is attributed to an increased environmental oxidation state. During this interval, seawater is known to have become richer in sulphate and iodate, which create ideal conditions for the abiotic and diagenetic oxidation of biomass. Therefore, increased occurrences of diagenetic spheroids in the Neoproterozoic possibly represent sedimentological evidence for abiotic decarboxylation reactions and widespread COR in productive environments. The distribution of diagenetic spheroids observed during the Proterozoic may also be more broadly applicable to other epochs of Earth’s history.
Study on the Rheological and Thixotropic Properties of Fiber-Reinforced Cemented Paste Backfill Containing Blast Furnace Slag
Authors: Zhao Xulin , Wang Haijun , Luo Guanghua , Dai Kewei , Hu Qinghua , Jin Junchao , Liu Yang , Liu Baowen , Miao Yonggang , Zhu Kunlei , Liu Jianbo , Zhang Hai , Wu Lianhe , Wu Jianming , Lu Yueming , Wang Wei , Lv Dingchao
Published: September 2024

To investigate the mechanism of polypropylene fiber (PPF) on the rheological and thixotropic properties of cemented paste backfill containing mineral admixtures, the concept of water film thickness (WFT) was introduced. The packing density of the tailings-binder-PPF (TBP) system was measured in dry and wet conditions and the WFT was calculated accordingly. Additionally, the rheological parameters (yield stress, thixotropy, etc.) of the fiber-reinforced cemented paste backfill (FRCPB) were quantified. The results demonstrate that the wet packing test is a more appropriate method for measuring the packing density of the TBP system. The PPF length has a slight adverse effect on the packing density, and the packing density initially increases and then decreases with the PPF content. The reasons can be attributed to the filling effect and wedge effect of the fibers, respectively. In addition to the packing density, the thixotropy of FRCPB is also affected by the interaction of fibers. WFT is a crucial factor affecting the yield stress of FRCPB, with which it exhibits a strong linear relationship. The study identified that the optimum PPF content for enhancing the rheological and thixotropic properties of CPB is 0.2%, with a fiber length of 9 mm, balancing flowability and stability for practical application in mining backfill operations. These insights can guide the optimization of CPB mixtures, enhancing their flowability and stability during placement in mined-out spaces. By improving the fill quality and reducing the risk of blockage during backfill operations, the results offer practical benefits in increasing the safety and efficiency of underground mining activities.
Optimization of Feature Selection in Mineral Prospectivity Using Ensemble Learning
Authors: Zhang Hong , Xie Miao , Dan Shiyao , Li Meilin , Li Yunhe , Yang Die , Wang Yuanxi
Published: September 2024

In recent years, machine learning (ML) has been extensively used for the quantitative prediction of mineral resources. However, the accuracy of prediction models is often influenced by data quality, feature selection, and algorithm limitations. This research investigates the benefits of data-driven feature optimization techniques in enhancing model accuracy. Using the Lhasa region in Tibet as the study area, this research applies ensemble learning methods, such as random forest and gradient boosting tree techniques, to optimize 43 feature variables encompassing geology, geochemistry, and geophysics. The optimized feature variables are then input into a support vector machine (SVM) model to generate a prospectivity map. The performance characteristics of the SVM, RF_SVM, and GBDT_SVM models are evaluated using ROC curves. The results indicate that the feature-optimized GBDT_SVM model achieves superior classification accuracy and prediction effectiveness, demonstrating that feature optimization is a necessary step for mineral prospectivity mapping, as it can significantly improve the performance of mineral prospectivity prediction.