bluuebunny/crossref_metadata_2025 huggingface dataset:
Autonomous Weapons Systems and the Contextual Nature of Hors de Combat Status
Authors: Umbrello Steven , Wood Nathan Gabriel
Published: May 2021

Autonomous weapons systems (AWS), sometimes referred to as “killer robots”, are receiving ever more attention, both in public discourse as well as by scholars and policymakers. Much of this interest is connected to emerging ethical and legal problems linked to increasing autonomy in weapons systems, but there is a general underappreciation for the ways in which existing law might impact on these new technologies. In this paper, we argue that as AWS become more sophisticated and increasingly more capable than flesh-and-blood soldiers, it will increasingly be the case that such soldiers are “in the power” of those AWS which fight against them. This implies that such soldiers ought to be considered hors de combat, and not targeted. In arguing for this point, we draw out a broader conclusion regarding hors de combat status, namely that it must be viewed contextually, with close reference to the capabilities of combatants on both sides of any discreet engagement. Given this point, and the fact that AWS may come in many shapes and sizes, and can be made for many different missions, we argue that each particular AWS will likely need its own standard for when enemy soldiers are deemed hors de combat. We conclude by examining how these nuanced views of hors de combat status might impact on meaningful human control of AWS.
The Journal of Ageing and Longevity: Taking a Holistic View of the Human Healthspan
Authors: Tully Mark A. , Pawelec Graham P.
Published: May 2021

It is our pleasure to inaugurate the new open access journal, the Journal of Ageing and Longevity (JAL, ISSN 2673-9259) [...]
Bleb Compressive Sutures in the Management of Hypotony Maculopathy after Glaucoma Surgery
Authors: Kosior-Jarecka Ewa , Wróbel-Dudzińska Dominika , Święch Anna , Żarnowski Tomasz
Published: May 2021

PURPOSE: The aim of the study was to assess the efficacy and safety of compressive sutures in patients with hypotony maculopathy after glaucoma surgery. METHODS: This retrospective case series analyzes the clinical outcomes of conjunctival compressive sutures in 17 patients with hypotony maculopathy developed after glaucoma surgery. Compressive Nylon 10–0 single sutures were used in all patients; in two patients, the procedure was repeated. All patients underwent ophthalmic evaluation and macular OCT scanning before the surgery, one month, six months, and one year after the procedure. RESULTS: Mean intraocular pressure (IOP) before suturing was 2.3 ± 1.57 mmHg and increased to 14.2 ± 7.03 mmHg (p = 0.00065) one month after the procedure. After six months, mean IOP was 10.2 ± 4.3 mmHg (p = 0.005), and after one year ± 4.7 mmHg (p = 0.0117). To obtain the target pressure, the sutures had to be removed in one patient, and medical therapy was undertaken in three patients. Mean decimal best-corrected visual acuity (BCVA) before the sutures was 0.18 ± 0.13 and increased to 0.53 ± 0.25 (p = 0.0004) after one month, to 0.46 ± 0.31 (p = 0.005) after six months, and to 0.31 ± 0.22 (p = 0.025) after one year. In one case, leakage from the bleb was observed after the procedure and bleb revision was required. CONCLUSIONS: transconjuctival compressive sutures seem to be an efficient and safe technique for managing hypotony maculopathy after glaucoma surgery.
Locked Away—Prophylaxis and Management of Catheter Related Thrombosis in Hemodialysis
Authors: Szymańska Joanna , Kakareko Katarzyna , Rydzewska-Rosołowska Alicja , Głowińska Irena , Hryszko Tomasz
Published: May 2021

Reliable vascular access is necessary for effective hemodialysis. Guidelines recommend chronic hemodialysis via an arteriovenous fistula (AVF), however, in a significant number of patients, permanent central venous catheters (CVCs) are used. The use of a tunneled catheter is acceptable if the estimated dialysis time is less than a year or it is not possible to create an AVF. The main complications associated with CVC include thrombosis and catheter-related bloodstream infections (CRBSIs), which may result in loss of vascular access. The common practice is to use locking solutions to maintain catheter patency and minimize the risk of CRBSI. This paperwork summarizes information on currently available locking solutions for dialysis catheters along with their effectiveness in preventing thrombotic and infectious complications and describes methods of dealing with catheter dysfunction. The PubMed database was systematically searched for articles about locking solutions used in permanent CVCs in hemodialysis patients. Additional studies were identified by searching bibliographies and international guidelines. Articles on end-stage kidney disease patients dialyzed through a permanent CVC were included. Information from each primary study was extracted using pre-determined criteria including thrombotic and infectious complications of CVC use, focusing on permanent CVC if sufficient data were available. Of the currently available substances, it seems that citrate at a concentration of 4% has the best cost-effectiveness and safety profile, which is reflected in the international guidelines. Recent studies suggest the advantage of 2+1 protocols, i.e., taurolidine-based solutions with addition of urokinase once a week, although it needs to be confirmed by further research. Regardless of the type of locking solution, if prophylaxis with a thrombolytic agent is chosen, it should be started from the very beginning to reduce the risk of thrombotic complications. In case of CVC dysfunction, irrespective of the thrombolysis attempt, catheter replacement should be planned as soon as possible.
Autologous Micro-Fragmented Adipose Tissue (MFAT) to Treat Symptomatic Knee Osteoarthritis: Early Outcomes of a Consecutive Case Series
Authors: Van Genechten Wouter , Vuylsteke Kristien , Martinez Pedro Rojas , Swinnen Linus , Sas Kristof , Verdonk Peter
Published: May 2021

The study aimed to evaluate the short-term clinical effect, therapeutic response rate (TRR%), and therapy safety of a single intra-articular autologous MFAT injection for symptomatic knee OA. Secondly, patient- and pathology-related parameters were investigated to tighten patient selection for MFAT therapy. Sixty-four subjects with symptomatic mild–severe knee OA were enrolled in a single-center trial and received a unilateral (n = 37) or bilateral (n = 27) MFAT injection. After liposuction, the adipose tissue was mechanically processed with the Lipogem® device, which eventually produced 8–10 cc of MFAT. Subjects were clinically assessed by means of the KOOS, NRS, UCLA, and EQ-5D at baseline and 1, 3, 6, and 12 months after injection. Adverse events were recorded at each follow-up timepoint. The TRR was defined according to the OMERACT-OARSI criteria and baseline MRI was scored following the MOAKS classification. The TRR of the index knee was 64% at 3 months and 45% at 12 months after injection. Therapy responders at 12 months improved with 28.3 ± 11.4 on KOOS pain, while non-responders lost −2.1 ± 11.2 points. All clinical scores, except the UCLA, improved significantly at follow-up compared to baseline (p < 0.05). In the bilateral cohort, no difference in baseline scores or TRR was found between the index knee and contralateral knee (n.s.). An inflammatory reaction was reported in 79% of knees and resolved spontaneously within 16.6 ± 13.5 days after MFAT administration. Numerous bone marrow lesions (BML) were negatively correlated with the TRR at 12 months (p = 0.003). The study demonstrated an early clinical improvement but a mediocre response rate of 45% at 12 months after a single intra-articular injection with autologous MFAT. Assessment of bone marrow lesions on MRI can be helpful to increase the therapeutic responsiveness of MFAT up to 70% at 12 months. In comparison to repetitive injection therapies such as cortisone, hyaluronic acid, and PRP, administration of MFAT might become a relevant alternative in well-selected patients with symptomatic knee OA.
Myasthenia Gravis: Epidemiology, Pathophysiology and Clinical Manifestations
Authors: Dresser Laura , Wlodarski Richard , Rezania Kourosh , Soliven Betty
Published: May 2021

Myasthenia gravis (MG) is an autoimmune neurological disorder characterized by defective transmission at the neuromuscular junction. The incidence of the disease is 4.1 to 30 cases per million person-years, and the prevalence rate ranges from 150 to 200 cases per million. MG is considered a classic example of antibody-mediated autoimmune disease. Most patients with MG have autoantibodies against the acetylcholine receptors (AChRs). Less commonly identified autoantibodies include those targeted to muscle-specific kinase (MuSK), low-density lipoprotein receptor-related protein 4 (Lrp4), and agrin. These autoantibodies disrupt cholinergic transmission between nerve terminals and muscle fibers by causing downregulation, destruction, functional blocking of AChRs, or disrupting the clustering of AChRs in the postsynaptic membrane. The core clinical manifestation of MG is fatigable muscle weakness, which may affect ocular, bulbar, respiratory and limb muscles. Clinical manifestations vary according to the type of autoantibody, and whether a thymoma is present.
Repeatability of Spectral Domain Optical Coherence Tomography Measurements of Bruch’s Membrane Opening-Minimum Rim Width in Epiretinal Membrane Patients with Peripapillary Involvement
Authors: Nam Ki Yup , Kim Bum Jun , Lee Woo Hyuk , Han Yong Seop
Published: May 2021

The Bruch’s membrane opening-minimum rim width (BMO-MRW) is a recently introduced parameter of the neuroretinal rim. We analyzed the repeatability of spectral-domain optical coherence tomography (SD-OCT) measurements of BMO-MRW in epiretinal membrane (ERM) patients with peripapillary involvement, since the surface around the optic disc is distorted in such patients. BMO-MRW and retinal nerve fiber layer (RNFL) thickness measurements were performed using SD-OCT in prospectively enrolled ERM patients and age-matched healthy control individuals. After two consecutive measurements with a 5 min interval, repeatability was analyzed using the intraclass correlation coefficient (ICC), repeatability coefficient (RC), and coefficient of variation (CV). Fifty-two eyes of 52 ERM patients and 62 eyes of 62 healthy controls were included in the study. The ICCs of the mean BMO-MRW/RNFL thickness measurements were 0.999/0.985 in ERM eyes and 0.999/0.999 in normal eyes, respectively. The RC values of mean BMO-MRW/RNFL thickness measurements were 9.0/6.25 μm in ERM eyes and 4.61/0.92 μm in normal eyes, respectively. The CV values were 0.91% and 1.45% for BMO-MRW and RNFL thickness in ERM eyes, and 0.63% and 0.33% in normal eyes, respectively. In ERM eyes, the RC, CV of average BMO-MRW were 1.9 and 1.4 times greater than those of normal eyes, but 6.8 and 4.4 times greater for average RNFL thickness. BMO-MRW and RNFL thickness showed good repeatability in the diseased eyes with peripapillary involvement and healthy control eyes. Based on the ICC, RC, and CV values, the repeatability of BMO-MRW measurements in peripapillary membrane patients was better than that of RNFL thickness.
High-Throughput Proteomic Profiling of Nipple Aspirate Fluid from Breast Cancer Patients Compared with Non-Cancer Controls: A Step Closer to Clinical Feasibility
Authors: George Amy L. , Shaheed Sadr ul , Sutton Chris W.
Published: May 2021

Background: Early detection of breast cancer (BC) is critical for increasing survival rates. However, current imaging approaches can provide ambiguous results, requiring invasive tissue biopsy for a definitive diagnosis. Multi-dimensional mass spectrometric analysis has highlighted the invaluable potential of nipple aspirate fluid (NAF) as a non-invasive source of early detection biomarkers, by identifying a multitude of proteins representative of the changing breast microenvironment. However, technical challenges with biomarker validation in large cohorts remain due to low sample throughput, impeding progress towards clinical utility. Rather, by employing a high-throughput method, that is more practicable for clinical utility, perturbations of the most abundant NAF proteins in BC patients compared with non-cancer (NC) controls could be monitored and validated in larger groups. Method: We characterized matched NAF pairs from BC (n = 9) and NC (n = 4) volunteers, using a rapid one dimensional liquid chromatography-mass spectrometry (1D LC-MS/MS) approach. Results: Overall, 198 proteins were relatively quantified, of which 40 were significantly differentiated in BC samples, compared with NC (p ≤ 0.05), with 26 upregulated and 14 downregulated. An imbalance in immune response and proteins regulating cell growth, maintenance and communication were identified. Conclusions: Our findings show 1D LC-MS/MS can quantify changes reflected in the NAF proteome associated with breast cancer development.
Multiple Task Assignment and Path Planning of a Multiple Unmanned Surface Vehicles System Based on Improved Self-Organizing Mapping and Improved Genetic Algorithm
Authors: Xia Guoqing , Sun Xianxin , Xia Xiaoming
Published: May 2021

This paper addresses multiple task assignment and path-planning problems for a multiple unmanned surface vehicle (USVs) system. Since it is difficult to solve multi-task allocation and path planning together, we divide them into two sub-problems, multiple task allocation and path planning, and study them separately. First, to resolve the multi-task assignment problem, an improved self-organizing mapping (ISOM) is proposed. The method can allocate all tasks in the mission area, and obtain the set of task nodes that each USV needs to access. Second, aiming at the path planning of the USV accessing the task nodes, an improved genetic algorithm (IGA) with the shortest path is proposed. To avoid USV collision during navigation, an artificial potential field function (APFF) is proposed. A multiple USV system with multi-task allocation and path planning is simulated. Simulation results verify the effectiveness of the proposed algorithms.
What Role Might Non-Mating Receptors Play in Schizophyllum commune?
Authors: Wirth Sophia , Freihorst Daniela , Krause Katrin , Kothe Erika
Published: May 2021

The B mating-type locus of the tetrapolar basidiomycete Schizophyllum commune encodes pheromones and pheromone receptors in multiple allelic specificities. This work adds substantial new evidence into the organization of the B mating-type loci of distantly related S. commune strains showing a high level of synteny in gene order and neighboring genes. Four pheromone receptor-like genes were found in the genome of S. commune with brl1, brl2 and brl3 located at the B mating-type locus, whereas brl4 is located separately. Expression analysis of brl genes in different developmental stages indicates a function in filamentous growth and mating. Based on the extensive sequence analysis and functional characterization of brl-overexpression mutants, a function of Brl1 in mating is proposed, while Brl3, Brl4 and Brl2 (to a lower extent) have a role in vegetative growth, possible determination of growth direction. The brl3 and brl4 overexpression mutants had a dikaryon-like, irregular and feathery phenotype, and they avoided the formation of same-clone colonies on solid medium, which points towards enhanced detection of self-signals. These data are supported by localization of Brl fusion proteins in tips, at septa and in not-yet-fused clamps of a dikaryon, confirming their importance for growth and development in S. commune.
Detection of Candida albicans-Specific CD4+ and CD8+ T Cells in the Blood and Nasal Mucosa of Patients with Chronic Rhinosinusitis
Authors: Ickrath Pascal , Sprügel Lisa , Beyersdorf Niklas , Scherzad Agmal , Hagen Rudolf , Hackenberg Stephan
Published: May 2021

Candida albicans is ubiquitously present, and colonization in the nose and oral cavity is common. In healthy patients, it usually does not act as a pathogen, but in some cases can cause diseases. The influence of C. albicans as a trigger of T cell activation on the pathogenesis of chronic rhinosinusitis (CRS) is controversial, and its exact role is not clear to date. The aim of the present study was to detect and characterize C. albicans-specific CD4+ and CD8+ T cells in patients with CRS, with and without nasal polyps. Tissue and blood samples were collected from patients suffering from chronic rhinosinusitis with (CRSwNP) and without nasal polyps (CRSsNP), and from healthy controls. A peptide pool derived from C. albicans antigen was added to tissue and blood samples. After 6 days, lymphocytes were analyzed by multicolor flow cytometry. Activation was assessed by the intracellular marker Ki-67, and the cytokine secretion was measured. Tissue CD8+ T cells of CRSsNP patients showed a significantly higher proportion of Ki-67+ cells after activation with C. albicans antigen compared to peripheral blood CD8+ T cells. Cytokine secretion in response to C. albicans antigen was similar for all study groups. In this study, C. albicans-specific CD4+ and CD8+ T cells were detected in peripheral blood and mucosal tissue in all study groups. In patients suffering from CRSsNP, C. albicans-specific CD8+ T cells were relatively enriched in the nasal mucosa, suggesting that they might play a role in the pathogenesis of CRSsNP.
Periprosthetic Fungal Infections in Severe Endoprosthetic Infections of the Hip and Knee Joint—A Retrospective Analysis of a Certified Arthroplasty Centre of Excellence
Authors: Enz Andreas , Mueller Silke C. , Warnke Philipp , Ellenrieder Martin , Mittelmeier Wolfram , Klinder Annett
Published: May 2021

The treatment of periprosthetic joint infections (PJI), and especially of re-infections, poses a highly complex problem in orthopaedic surgery. While fungal infections are rare, they present a special challenge. The therapy is often protracted and based on limited evidence. A total of 510 hip and knee revision surgeries were analysed for the occurrence of bacterial and fungal PJI. In patients with PJI, the duration of the hospital stay and the incidence of disarticulation of the infected joint were recorded. Out of the analysed revision arthroplasties, 43.5% were due to PJI. Monomicrobial infection occurred in 55.2%, dual microbial infection in 21.4%, and polymicrobial (≥3 different bacterial or fungal species) infection in 17.2% of the cases. Overall, Candida species were detected in 12.4% cases. Candida albicans was the main fungal pathogen. In 6.9% of cases, disarticulation of the joint was the only option to control PJI. The detection of polymicrobial infection more than doubled in follow-up revisions and there was a strong association between detection of Candida infection and disarticulation (OR 9.39). The majority of fungal infections were mixed infections of bacteria and Candida albicans. The choice of a biofilm penetrating antimycotic, e.g., caspofungin, together with a sufficient standard procedure for detection and surgical treatment can help to control the infection situation. Fungal infection often proves to be more difficult to treat than anticipated and is more frequent than expected.
Model-Based Assessment of Giant Reed (Arundo donax L.) Energy Yield in the Form of Diverse Biofuels in Marginal Areas of Italy
Authors: Cappelli Giovanni Alessandro , Ginaldi Fabrizio , Fanchini Davide , Corinzia Sebastiano Andrea , Cosentino Salvatore Luciano , Ceotto Enrico
Published: May 2021

Giant reed is a promising perennial grass providing ligno-cellulosic biomass suitable to be cultivated in marginal lands (MLs) and converted into several forms of renewable energy. This study investigates how much energy, in the form of biomethane, bioethanol, and combustible solid, can be obtained by the cultivation of this species in marginal land of two Italian regions, via the spatially explicit application of the Arungro crop model. Arungro was calibrated in both rainfed/well-irrigated systems, under non-limiting conditions for nutrient availability. The model was then linked to a georeferenced database, with data on (i) current/future climate, (ii) agro-management, (iii) soil physics/hydrology, (iv) land marginality, and (v) crop suitability to environment. Simulations were run at 500 × 500 m spatial resolution in MLs of Catania (CT, Southern Italy) and Bologna (BO, Northern Italy) provinces, characterized by contrasting pedo-climates. At field scale, Arungro explained 85% of the year-to-year variability of measured carbon accumulation in aerial biomass. At the provincial level, simulated energy yields progressively increased from bioethanol, to biomethane, and finally to combustible solid, with average values of 92-115-264 GJ ha−1 in BO and 105-133-304 GJ ha−1 in CT. Mean energy yields estimated for 2030 remained unchanged compared to the baseline, although showing large heterogeneity across the study area (changes between −6/+15% in BO and −16/+15% in CT). This study provides site-specific indications on giant reed current productions, energy yields, and natural water consumption, as well as on their future trends and stability, ready-to-use for multiple stakeholders of the agricultural sector involved in bioenergy planning.
Planar Contact Fretting Test Method Applied to Solid Lubricants
Authors: Buse Henrik , Schueler Fabian , Hodúlová Erika
Published: May 2021

A new method of material and lubricant testing is demonstrated with a planar contact fretting wear tribometer under typical fretting wear conditions. The usual abstraction of contact geometries with an easy-to-align point or line contacts is deliberately dispensed to do justice to the frequently flat contacts of machine elements (shaft-hub connection, bearing seats, etc.). For the study, a new method of targeted observation of the contact surfaces during the test is used, which allows a time-lapse animation of the fretting wear progress of solid lubricant mixtures. Thus, the formation of possible transfer film build-up and the type of wear mechanism occurring can be visualized. This technique represents, in conjunction with additional analytical methods such as microscopy and SEM/EDX, a powerful tool to provide a better insight into the mechanisms of solid lubricant action under fretting conditions. To demonstrate the potential of this approach, a time to damage study is performed on commercial and self-prepared pastes from solid lubricants and white oil, where calcium hydroxide is a commonly employed solid lubricant for the avoidance of fretting wear is compared to other materials.
Deterioration of Portland Cement Pervious Concrete in Sponge Cities Subjected to Acid Rain
Authors: Gao Longxin , Lai Yong , Islam Pramanic Mohammad Rashadul , Zhang Wuman
Published: May 2021

The deterioration of Portland cement pervious concrete (PCPC) subjected to wet-dry cycles in the simulated acid rain solution was investigated; 4% silica fume (SF) and 8% fine aggregate (FAG) were used to replace part of cement and the coarse aggregates (weight by weight), respectively. The wear resistance, the compressive, and flexural strength of PCPC were measured. The results show that after 12 wet-dry cycles in acid rain solution the compressive strength and the flexural strength of control PCPC are decreased by 30.7% and 40.8%. The final compressive strength of PCPC with 4% SF and PCPC with 8% FAG is increased by 6.9% and 30.3%, and the final flexural strength is increased by 25.4% and 72.3%, respectively. The wear loss of PCPC is decreased by 58.8% and 81.9% when 4% SF and 8% FAG is added to PCPC, respectively. The microstructures of PCPC with wet-dry cycles are also discussed.
Influence of Shielding Gas on Microstructure and Properties of GMAW DSS2205 Welded Joints
Authors: Zhang Xin-Yu , Zha Xiao-Qin , Gao Ling-Qing , Hei Peng-Hui , Ren Yong-Feng
Published: May 2021

In the present study, the microstructures and properties of DSS 2205 solid wire MIG welded samples prepared in different shielding gases (pure Ar gas, 98%Ar + 2%O2 and 98%Ar + 2%N2) were investigated for improving the weldability of DSS 2205 welded joint. The work was conducted by mechanical property tests (hardness and tensile test) and corrosion resistance property tests (immersion and electrochemical tests). The results show that adding 2%O2 into pure Ar gas as the shielding gas decreases crystal defects (faults) and improves the mechanical properties and corrosion resistance of the welded joints. Phase equilibrium and microstructural homogeneity in welded seam (WS) and heat-affected zone (HAZ) can be adjusted and the strength and corrosion resistance of welded joints increased obviously by adding 2%N2 to pure Ar gas as the shielding gas. Compared with DSS 2205 solid wire MIG welding in 98%Ar + 2%O2 mixed atmosphere, the strength and corrosion resistance of welded joints are improved more obviously in 98%Ar + 2%N2 mixed atmosphere.
Physical Properties, Spectroscopic, Microscopic, X-ray, and Chemometric Analysis of Starch Films Enriched with Selected Functional Additives
Authors: Combrzyński Maciej , Oniszczuk Tomasz , Kupryaniuk Karol , Wójtowicz Agnieszka , Mitrus Marcin , Milanowski Marek , Soja Jakub , Budziak-Wieczorek Iwona , Karcz Dariusz , Kamiński Daniel , Kulesza Sławomir , Wojtunik-Kulesza Karolina , Kasprzak-Drozd Kamila , Gancarz Marek , Kowalska Iwona , Ślusarczyk Lidia , Matwijczuk Arkadiusz
Published: May 2021

Biodegradable materials are used in the manufacture of packaging and compostable films and various types of medical products. They have demonstrated a large number of potential practical applications in medicine and particularly in the treatment of various cardiac, vascular, and orthopedic conditions in adults as well in children. In our research, the extrusion-cooking technique was applied to prepare thermoplastic starch (TPS), which was then utilized to obtain environmentally friendly starch-based films. Potato starch was the basic raw material exploited. Polyvinyl alcohol and keratin were used as functional additives in amounts from 0.5 to 3%, while 20% of glycerol was harnessed as a plasticizer. The processing of the thermoplastic starch employed a single screw extruder-cooker with an L/D ratio of 16. The film blowing process was carried out using a film-blowing laboratory line with L/D = 36. FTIR Spectroscopy was applied for the assignment of the prominent functional groups. The results showed that the processing efficiency of thermoplastic starch with functional additives varied depending on the level of polyvinyl alcohol and keratin addition. Moreover, the FTIR data correlated with the changes in the physical properties of the tested films. The analysis of FTIR spectra revealed several changes in the intensity of bands originating from stretching vibrations characteristic of the –OH substituent. The changes observed depended on the presence/lack of the hydrogen bonding occurring upon interactions between the starch molecules and the various additives used. In addition, notable changes were observed in bands assigned to glycoside bonds in the starch.
Using TOF-SIMS Spectrometry to Study the Kinetics of the Interfacial Retro Diels–Alder Reaction
Authors: Hassouna Lilia , Enganati Sachin Kumar , Bally-Le Gall Florence , Mertz Grégory , Bour Jérôme , Ruch David , Roucoules Vincent
Published: May 2021

In this work, the use of Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) was explored as a technique for monitoring the interfacial retro Diels–Alder (retro DA) reaction occurring on well-controlled self-assembled monolayers (SAMs). A molecule containing a Diels–Alder (DA) adduct was grafted on to the monolayers, then the surface was heated at different temperatures to follow the reaction conversion. A TOF-SIMS analysis of the surface allowed the detection of a fragment from the molecule, which is released from the surface when retro DA reaction occurs. Hence, by monitoring the decay of this fragment’s peak integral, the reaction conversion could be determined in function of the time and for different temperatures. The viability of this method was then discussed in comparison with the results obtained by 1H NMR spectroscopy.
New Low-Melting Triply Charged Homoleptic Cr(III)-Based Ionic Liquids in Comparison to Their Singly Charged Heteroleptic Analogues
Authors: Peppel Tim , Köckerling Martin
Published: May 2021

A series of new low-melting triply charged homoleptic Cr(III)-based ionic liquids of the general formula (RMIm)3[Cr(NCS)6] (R = methyl, ethyl, n-butyl, benzyl) is reported. Their syntheses and properties are described in comparison to their singly charged heteroleptic analogues of the general formula (RMIm)[Cr(NCS)4L2] (R = methyl, ethyl, n-butyl, benzyl; L = pyridine, γ-picoline). In total, sixteen new Reineckate related salts with large imidazolium cations are described. Out of these, five compounds were crystallized, and their structures determined by single-crystal X-ray structure analyses. They all consisted of discrete anions and cations with octahedrally coordinated Cr(III) ions. In the structures, various hydrogen contacts interconnect the entities to build up hydrogen bonded networks. Thermal investigations showed relatively low melting points for the homoleptic complexes. The compounds with the [Cr(NCS)6]3− anion melt without decomposition and are stable up to 200 K above their melting points. The complex salts with the [Cr(NCS)4L2]− anion, in contrast, start to decompose and lose L molecules (Pyr or Pic) already at the melting point.
Dynamic Covalent Bonds of Si-OR and Si-OSi Enabled A Stiff Polymer to Heal and Recycle at Room Temperature
Authors: Fan Ping , Xue Can , Zhou Xiantai , Yang Zujin , Ji Hongbing
Published: May 2021

As stiff polymers are difficult to self-heal, the balance between polymers’ self-healing ability and mechanical properties is always a big challenge. Herein, we have developed a novel healable stiff polymer based on the Si-OR and Si-OSi dynamic covalent bonds. The self-healing mechanism was tested and proved by the small molecule model experiments and the contrast experiments of polymers. This polymer possesses excellent tensile, bending properties as well as room temperature self-healing abilities. Moreover, due to the sticky and shapeable properties under wetting conditions, the polymer could be used as an adhesive. Besides, even after four cycles of recycling, the polymer maintains its original properties, which meets the requirements of recyclable materials. It was demonstrated that the polymer exhibits potential application in some fields, such as recyclable materials and healable adhesives.
High Temperature Electrical Properties of Co-Substituted La4BaCu5O13+δ Thin Films Fabricated by Sputtering Method
Authors: Shin Woosuck , Tsuruta Akihiro , Itoh Toshio , Akamatsu Takafumi , Terasaki Ichiro
Published: May 2021

The high-temperature conductivity of the perovskite oxides of a La4BaCu5O13+δ (LBCO) thin film prepared by RF sputtering deposition and thermal annealing has been studied. While the bulk LBCO compound was metallic, the LBCO film deposited on a Si substrate by sputtering and a post annealing process showed semiconductor-like conduction, which is considered to be due to the defects and poor grain connectivity in the LBCO film on the Si substrate. The LBCO film deposited on a SrTiO3 substrate was of high film quality and showed metallic conduction. When the cation site Cu was substituted by Co, the electrical conductivity of the LBCO film increased further and its temperature dependence became smaller. The transport properties of LBCO films are investigated to understand its carrier generation mechanism.
Viscoelastic Properties of Epoxidized Natural Rubber/Poly(lactic acid) PLA/ENR Blends Containing Glycidyl-POSS and Trisilanolisooctyl-POSS as Functional Additives
Authors: Lipińska Magdalena , Toczek Klaudia , Stefaniak Magdalena
Published: May 2021

The glycidyl-POSS (Polyhedral Oligomeric Silsesquioxanes, Polysilsesquioxane, POSS) (Gly-POSS) and trisilanolisooctyl-POSS (HO-POSS) were applied as functional additives influencing on the viscoelastic properties of the dynamic vulcanized PLA/ENR (poly(lactic acid)/epoxidized natural rubber) blends. The plasticizing effect of HO-POSS on PLA/ENR melt, leading to the decrease of complex viscosity at 160 °C, was observed. After the incorporation of Gly-POSS into PLA/ENR blends the complex viscosity increased confirming that the epoxy groups of Gly-POSS were able to react with the functional groups of ENR and the groups present at the end of PLA chains. The incorporation of Gly-POSS into 40:60 PLA/ENR blend provided significant enhancement of the storage shear modulus G’ at 30 °C. Furthermore, the glass transition temperatures Tg of ENR phase for PLA/ENR/Gly-POSS blends were shifted to higher values of temperature as compared with blends modified by HO-POSS. Strong reduction of the elongation at break Eb for 40:60 PLA/ENR/Gly-POSS blend indicated that Gly-POSS particles acted as multifunctional cross-links reducing elasticity of the material. The modification of 40:60 PLA/ENR blend by HO-POSS molecules led to lower values of composting coefficient KC indicating stronger deterioration of the mechanical properties that resulted from more intense degradation processes occurring during disposal in soil.
Experimental and Numerical Study of Fracture Behavior of Rock-Like Material Specimens with Single Pre-Set Joint under Dynamic Loading
Authors: Pan Bo , Wang Xuguang , Xu Zhenyang , Guo Lianjun , Wang Xuesong
Published: May 2021

The Split Hopkinson Pressure Bar (SHPB) is an apparatus for testing the dynamic stress-strain response of the cement mortar specimen with pre-set joints at different angles to explore the influence of joint attitudes of underground rock engineering on the failure characteristics of rock mass structure. The nuclear magnetic resonance (NMR) has also been used to measure the pore distribution and internal cracks of the specimen before and after the testing. In combination with numerical analysis, the paper systematically discusses the influence of joint angles on the failure mode of rock-like materials from three aspects of energy dissipation, microscopic damage, and stress field characteristics. The result indicates that the impact energy structure of the SHPB is greatly affected by the pre-set joint angle of the specimen. With the joint angle increasing, the proportion of reflected energy moves in fluctuation, while the ratio of transmitted energy to dissipated energy varies from one to the other. NMR analysis reveals the structural variation of the pores in those cement specimens before and after the impact. Crack propagation direction is correlated with pre-set joint angles of the specimens. With the increase of the pre-set joint angles, the crack initiation angle decreases gradually. When the joint angles are around 30°–75°, the specimens develop obvious cracks. The crushing process of the specimens is simulated by LS-DYNA software. It is concluded that the stresses at the crack initiation time are concentrated between 20 and 40 MPa. The instantaneous stress curve first increases and then decreases with crack propagation, peaking at different times under various joint angles; but most of them occur when the crack penetration ratio reaches 80–90%. With the increment of joint angles in specimens through the simulation software, the changing trend of peak stress is consistent with the test results.
Interlaminar Fracture Behavior of Carbon Fiber/Polyimide Composites Toughened by Interleaving Thermoplastic Polyimide Fiber Veils
Authors: Lan Bangwei , Liu Yi , Mo Song , He Minhui , Zhai Lei , Fan Lin
Published: May 2021

Carbon fiber reinforced thermosetting polyimide (CF/TSPI) composites were interleaved with thermally stable thermoplastic polyimide (TPPI) fiber veils in order to improve the interlaminar fracture toughness without sacrificing the heat resistance. Both of the mode I and mode II interlaminar fracture toughness (GIC and GIIC) for the untoughened laminate and TPPI fiber veils interleaved laminates were characterized by the double cantilever beam (DCB) test and end notch flexure (ENF) test, respectively. It is found that the TPPI fiber veils interleaved laminates exhibit extremely increased fracture toughness than the untoughened one. Moreover, the areal density of TPPI greatly affected the fracture toughness of laminates. A maximum improvement up to 179% and 132% on GIC and GIIC is obtained for 15 gsm fiber veils interleaved laminate, which contributes to the existence of bicontinuous TPPI/TSPI structure in the interlayer according to the fractography analysis. The interlaminar fracture behavior at elevated temperatures for 15 gsm fiber veils interleaved laminate were also investigated. The results indicated that the introduction of thermally stable TPPI fiber veils could enhance the fracture toughness of CF/TSPI composites by exceeding 200% as compared to the untoughened one even as tested at 250 °C.
Neutron Studies of a High Spin Fe19 Molecular Nanodisc
Authors: Pratt Francis L. , Guidi Tatiana , Manuel Pascal , Anson Christopher E. , Tang Jinkui , Blundell Stephen J. , Powell Annie K.
Published: May 2021

The molecular cluster system [Fe19(metheidi)10(OH)14O6(H2O)12]NO3·24H2O, abbreviated as Fe19, contains nineteen Fe(III) ions arranged in a disc-like structure with the total spin S = 35/2. For the first order, it behaves magnetically as a single molecule magnet with a 16 K anisotropy barrier. The high spin value enhances weak intermolecular interactions for both dipolar and superexchange mechanisms and an eventual transition to antiferromagnetic order occurs at 1.2 K. We used neutron diffraction to determine both the mode of ordering and the easy spin axis. The observed ordering was not consistent with a purely dipolar driven order, indicating a significant contribution from intermolecular superexchange. The easy axis is close to the molecular Fe1–Fe10 axis. Inelastic neutron scattering was used to follow the magnetic order parameter and to measure the magnetic excitations. Direct transitions to at least three excited states were found in the 2 to 3 meV region. Measurements below 0.2 meV revealed two low energy excited states, which were assigned to S = 39/2 and S = 31/2 spin states with respective excitation gaps of 1.5 and 3 K. Exchange interactions operating over distances of order 10 Å were determined to be on the order of 5 mK and were eight-times stronger than the dipolar coupling.
High-Performance Tracking for Proton Exchange Membrane Fuel Cell System PEMFC Using Model Predictive Control
Authors: Derbeli Mohamed , Charaabi Asma , Barambones Oscar , Napole Cristian
Published: May 2021

Proton exchange membrane (PEM) fuel cell has recently attracted broad attention from many researchers due to its cleanliness, high efficiency and soundless operation. The obtention of high-performance output characteristics is required to overcome the market restrictions of the PEMFC technologies. Therefore, the main aim of this work is to maintain the system operating point at an adequate and efficient power stage with high-performance tracking. To this end, a model predictive control (MPC) based on a global minimum cost function for a two-step horizon was designed and implemented in a boost converter integrated with a fuel cell system. An experimental comparative study has been investigated between the MPC and a PI controller to reveal the merits of the proposed technique. Comparative results have indicated that a reduction of 15.65% and 86.9%, respectively, in the overshoot and response time could be achieved using the suggested control structure.
Outsourcing of Human Resources: The Case of Small- and Medium-Sized Enterprises
Authors: Edvardsson Ingi Runar , Óskarsson Guðmundur Kristján
Published: May 2021

The outsourcing of human resources has increased in recent years. As in other fields of management research, limited knowledge is available on outsourcing in small- and medium-sized enterprises (SMEs). The aim of this paper is to present a study on the outsourcing of human resources in Icelandic service SMEs in the period 2009–2018. Surveys were used to gather information on outsourcing, with the participation of 802 firms. The results show that three out of four firms have outsourced some activities, while only 21% have formulated a formal strategy for outsourcing. The main motives for outsourcing are accessing expertise and simplifying operations. Cost reduction comes in third place. SMEs tend to outsource human resources on a very limited scale, while 50% of firms outsource information technology and 39% outsource security services. Larger firms outsource human resources on a larger scale than smaller firms. Managers in companies that outsource human resources are more satisfied with many aspects of outsourcing compared to those managers who do not outsource those resources. Firms that outsource human resources also realise more actual cost reduction. Outsourcing in SMEs has little impact on employment, as 3% of firms lay off staff and 6% transfer staff to vendors. Larger firms and firms that outsource human resources are more likely to change their staff’s employment status after outsourcing.
Metabolic Profiling from an Asymptomatic Ferret Model of SARS-CoV-2 Infection
Authors: Beale David J. , Shah Rohan , Karpe Avinash V. , Hillyer Katie E. , McAuley Alexander J. , Au Gough G. , Marsh Glenn A. , Vasan Seshadri S.
Published: May 2021

Coronavirus disease (COVID-19) is a contagious respiratory disease that is causing significant global morbidity and mortality. Understanding the impact of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection on the host metabolism is still in its infancy but of great importance. Herein, we investigated the metabolic response during viral shedding and post-shedding in an asymptomatic SARS-CoV-2 ferret model (n = 6) challenged with two SARS-CoV-2 isolates. Virological and metabolic analyses were performed on (minimally invasive) collected oral swabs, rectal swabs, and nasal washes. Fragments of SARS-CoV-2 RNA were only found in the nasal wash samples in four of the six ferrets, and in the samples collected 3 to 9 days post-infection (referred to as viral shedding). Central carbon metabolism metabolites were analyzed during viral shedding and post-shedding periods using a dynamic Multiple Reaction Monitoring (dMRM) database and method. Subsequent untargeted metabolomics and lipidomics of the same samples were performed using a Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-QToF-MS) methodology, building upon the identified differentiated central carbon metabolism metabolites. Multivariate analysis of the acquired data identified 29 significant metabolites and three lipids that were subjected to pathway enrichment and impact analysis. The presence of viral shedding coincided with the challenge dose administered and significant changes in the citric acid cycle, purine metabolism, and pentose phosphate pathways, amongst others, in the host nasal wash samples. An elevated immune response in the host was also observed between the two isolates studied. These results support other metabolomic-based findings in clinical observational studies and indicate the utility of metabolomics applied to ferrets for further COVID-19 research that advances early diagnosis of asymptomatic and mild clinical COVID-19 infections, in addition to assessing the effectiveness of new or repurposed drug therapies.
A Comparative Study on the Wettability of Unstructured and Structured LiFePO4 with Nanosecond Pulsed Fiber Laser
Authors: Berhe Mulugeta Gebrekiros , Lee Dongkyoung
Published: May 2021

The wettability of electrodes increases the power and energy densities of the cells of lithium-ion batteries, which is vital to improving their electrochemical performance. Numerous studies in the past have attempted to explain the effect of electrolyte and calendering on wettability. In this work, the wettability behavior of structured and unstructured LiFePO4 electrodes was studied. Firstly, the wettability morphology of the structured electrode was analyzed, and the electrode geometry was quantified in terms of ablation top and bottom width, ablation depth, and aspect ratio. From the result of the geometry analysis, the minimum measured values of aspect ratio and ablation depth were used as structured electrodes. Laser structuring with pitch distances of 112 μm, 224 μm, and 448 μm was applied. Secondly, the wettability of the electrodes was measured mainly by total wetting time and electrolyte spreading area. This study demonstrates that the laser-based structuring of the electrode increases the electrochemically active surface area of the electrode. The electrode structured with 112 μm pitch distance exhibited the fastest wetting at a time of 13.5 s. However, the unstructured electrode exhibited full wetting at a time of 84 s.
Editorial for the Special Issue on Inertial Microfluidics
Authors: Hur Soojung Claire , Lee Wonhee
Published: May 2021

The growing demands for label-free, high throughput processing of biological, environmental, and industrial samples have instigated technical innovations for inflow particle manipulations with better resolution and purity [...]
Amino Acid Residues Involved in Inhibition of Host Gene Expression by Influenza A/Brevig Mission/1/1918 PA-X
Authors: Chiem Kevin , Martinez-Sobrido Luis , Nogales Aitor , DeDiego Marta L.
Published: May 2021

The influenza A virus (IAV) PA-X protein is a virulence factor that selectively degrades host mRNAs leading to protein shutoff. This function modulates host inflammation, antiviral responses, cell apoptosis, and pathogenesis. In this work we describe a novel approach based on the use of bacteria and plasmid encoding of the PA-X gene under the control of the bacteriophage T7 promoter to identify amino acid residues important for A/Brevig Mission/1/1918 H1N1 PA-X’s shutoff activity. Using this system, we have identified PA-X mutants encoding single or double amino acid changes, which diminish its host shutoff activity, as well as its ability to counteract interferon responses upon viral infection. This novel bacteria-based approach could be used for the identification of viral proteins that inhibit host gene expression as well as the amino acid residues responsible for inhibition of host gene expression.
Chalcopyrite and Molybdenite Flotation in Seawater: The Use of Inorganic Dispersants to Reduce the Depressing Effects of Micas
Authors: Yepsen Rodrigo , Roa Joaquín , Toledo Pedro G. , Gutiérrez Leopoldo
Published: May 2021

The objective of this work was to study the effect of muscovite and biotite on the flotation of chalcopyrite and molybdenite in seawater, and the use of sodium hexametaphosphate and sodium silicate to improve copper and molybdenum recoveries. The impact of the inorganic dispersants on the settling properties of the resulting flotation tailings was also studied. It was found that muscovite and biotite depress the flotation of chalcopyrite and molybdenite in seawater, with this depressing effect being stronger at pH 11 than at pH 9. Sodium hexametaphosphate and sodium silicate increased the recoveries of copper and molybdenum in seawater. These dispersants render the mineral particles more negatively charged and remove the hydroxy-complexes of magnesium and calcium from the mineral particles causing dispersion of the slimes. The settling rates of the flotation tailings slightly decrease when sodium hexametaphosphate and sodium silicate were added in the flotation stage. The presence of ultrafine particles dispersed by the action of the inorganic dispersants negatively impacted the flocculation and sedimentation processes leading to high flocculant consumption, low settling rates and high turbidity of the supernatant.