bluuebunny/crossref_metadata_2025 huggingface dataset:
Search Heuristics and Constructive Algorithms for Maximally Idempotent Integers
Authors: Fagin Barry
Published: July 2021

Previous work established the set of square-free integers n with at least one factorization n=p¯q¯ for which p¯ and q¯ are valid RSA keys, whether they are prime or composite. These integers are exactly those with the property λ(n)∣(p¯−1)(q¯−1), where λ is the Carmichael totient function. We refer to these integers as idempotent, because ∀a∈Zn,ak(p¯−1)(q¯−1)+1≡na for any positive integer k. This set was initially known to contain only the semiprimes, and later expanded to include some of the Carmichael numbers. Recent work by the author gave the explicit formulation for the set, showing that the set includes numbers that are neither semiprimes nor Carmichael numbers. Numbers in this last category had not been previously analyzed in the literature. While only the semiprimes have useful cryptographic properties, idempotent integers are deserving of study in their own right as they lie at the border of hard problems in number theory and computer science. Some idempotent integers, the maximally idempotent integers, have the property that all their factorizations are idempotent. We discuss their structure here, heuristics to assist in finding them, and algorithms from graph theory that can be used to construct examples of arbitrary size.
Characteristics of Crashes Caused by Distracted Driving on Rural and Suburban Roadways in Jordan
Authors: Al-Rousan Taleb M. , Umar Abdullahi A. , Al-Omari Aslam A.
Published: July 2021

The objective of this study was to identify the most salient driver faults that cause crashes on some Jordanian rural and suburban roadway segments, to examine crashes with distracted driving as the driver’s fault, and to investigate the differences between crashes caused by distracted driving. Data for more than 10,200 crashes on nine roadway segments (five rural and four suburban) were accessed from the relevant government agency, but only n = 2472 were used for analysis after controlling for crashes specified as being caused by drivers’ distracted driving. IBM SPSS version 22 was used to perform descriptive analysis and independent samples’ t-tests. The results revealed that distracted driving was the second most common driver fault to cause crashes and the second main cause of fatalities and injuries on both rural and suburban roadways. Distracted driving on rural highways appears to be more fatal, whereas it caused more crashes with severe injuries on suburban roads. The variables at junction, road grade, number of lanes, weather condition, crash type, and number of vehicles involved were found to be statistically significant but with a small effect size. The following categories showed high percentages of distracted driving crashes on rural and suburban roadways: males, drivers 25–39 years old, non-holidays, weekdays, tangent sections, two-way divided roads, not at junction, level roads, two-lane roads, clear weather, dry surface, daylight, and automobile vehicles showed high percentages of distracted driving crashes on rural and suburban roadways. Differences between crashes on rural and suburban roadways caused by distracted driving were found to be small.
Assessing Parent Behaviours in Parent–Child Interactions with Deaf and Hard of Hearing Infants Aged 0–3 Years: A Systematic Review
Authors: Curtin Martina , Dirks Evelien , Cruice Madeline , Herman Rosalind , Newman Lauren , Rodgers Lucy , Morgan Gary
Published: July 2021

Background: Despite early identification and advancements in cochlear implant and hearing aid technology, delays in language skills in deaf children continue to exist. Good-quality parent–child interaction (PCI) is a key predictor for the successful development of deaf children’s signed and/or spoken language. Though professionals have standard assessments to monitor child language, a clinical tool to observe the quality of parental interaction is yet to be developed. Aims and methods: This systematic review with narrative synthesis aims to uncover which parent behaviours are assessed in PCI studies with deaf infants aged 0–3 years, how these behaviours are assessed, and which are correlated with higher scores in child language. Results: Sixty-one papers were included, spanning 40 years of research. Research included in the review assessed parents’ skills in gaining attention, joint engagement, emotional sensitivity, and language input. PCI was mostly assessed using coding systems and frame-by-frame video analysis. Some of the parent behaviours mentioned previously are associated with more words produced by deaf children. Conclusion: The results of the review provide the evidence base required to develop the content of a future clinical assessment tool for parent–child interaction in deafness.
SARS-CoV-2 and Acute Cerebrovascular Events: An Overview
Authors: Ghasemi Mehdi , Umeton Raffaella Pizzolato , Keyhanian Kiandokht , Mohit Babak , Rahimian Nasrin , Eshaghhosseiny Niloofarsadaat , Davoudi Vahid
Published: July 2021

Since the coronavirus disease 2019 (COVID-19) pandemic, due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, accumulating evidence indicates that SARS-CoV-2 infection may be associated with various neurological manifestations, including acute cerebrovascular events (i.e., stroke and cerebral venous thrombosis). These events can occur prior to, during and even after the onset of COVID-19’s general symptoms. Although the mechanisms underlying the cerebrovascular complications in patients with COVID-19 are yet to be fully elucidated, the hypercoagulability state, inflammation and altered angiotensin-converting enzyme 2 (ACE-2) signaling in association with SARS-CoV-2 may play key roles. ACE-2 plays a critical role in preserving heart and brain homeostasis. In this review, we discuss the current state of knowledge of the possible mechanisms underlying the acute cerebrovascular events in patients with COVID-19, and we review the current epidemiological studies and case reports of neurovascular complications in association with SARS-CoV-2, as well as the relevant therapeutic approaches that have been considered worldwide. As the number of published COVID-19 cases with cerebrovascular events is growing, prospective studies would help gather more valuable insights into the pathophysiology of cerebrovascular events, effective therapies, and the factors predicting poor functional outcomes related to such events in COVID-19 patients.
NF1-Dependent Transcriptome Regulation in the Melanocyte Lineage and in Melanoma
Authors: Larribère Lionel , Utikal Jochen
Published: July 2021

The precise role played by the tumor suppressor gene NF1 in melanocyte biology and during the transformation into melanoma is not completely understood. In particular, understanding the interaction during melanocyte development between NF1 and key signaling pathways, which are known to be reactivated in advanced melanoma, is still under investigation. Here, we used RNAseq datasets from either situation to better understand the transcriptomic regulation mediated by an NF1 partial loss of function. We found that NF1 mutations had a differential impact on pluripotency and on melanoblast differentiation. In addition, major signaling pathways such as VEGF, senescence/secretome, endothelin, and cAMP/PKA are likely to be upregulated upon NF1 loss of function in both melanoblasts and metastatic melanoma. In sum, these data bring new light on the transcriptome regulation of the NF1-mutated melanoma subgroup and will help improve the possibilities for specific treatment.
Outcomes of Computer-Assisted Total Knee Arthroplasty Compared to Conventional TKA: A Bicentric Controlled Retrospective Clinical Study
Authors: Zampogna Biagio , Campi Stefano , Torre Guglielmo , Villari Eleonora , Moncada Francesco , Perrino Aristide , Ciriaco Letterio , Ferlazzo Marco , Papalia Rocco , Denaro Vincenzo
Published: July 2021

Despite the globally ascertained success of Total Knee Arthroplasty (TKA) procedure, 20% of patients are still unsatisfied with the surgery results. The purpose of the study is to identify the functional and radiological outcomes of the computer-assisted (CAS) TKA compared to the conventional technique. The clinical databases and medical records of both clinical sites were retrospectively analyzed, and then according to study time-lapse, inclusion, and exclusion criteria, eligible patients were retrieved and included. A total of 42 patients that underwent to CAS TKA (NAVI) and 61 patients that underwent to Conventional TKA (CONV) were included. The NAVI group reported a statistically significant higher surgical time. A lower intraoperative blood loss was found in the computer-assisted group, though this difference was not statistically significant. Implant survival analysis at two years did not show differences between groups during the follow-up period. At two years, follow-up postoperative intergroup analysis showed no statistically significant difference between groups. According to the radiologic analysis, the NAVI group showed comparable outcomes to the conventional group. The present study showed that there was no clinical and radiological difference between CAS arthroplasty and conventional technique.
Association of Baseline Cardiovascular Diseases with 5-Year Knee and Hip Osteoarthritis Progression in Non-Obese Patients: Data from the KHOALA Cohort
Authors: Roubille Camille , Coste Joël , Sellam Jérémie , Rat Anne-Christine , Guillemin Francis , Roux Christian H.
Published: July 2021

We aimed to explore the relationship between comorbidities and the structural progression in symptomatic knee and/or hip osteoarthritis (OA) patients. We analyzed the 5-year outcome of non-obese participants (body mass index (BMI) < 30 kg/m2) from the KHOALA cohort having symptomatic hip and/or knee OA (Kellgren and Lawrence (KL) ≥ 2). The primary endpoint was radiological progression, defined as ΔKL ≥ 1 of the target joint at 5 years. The secondary outcome was the incidence of total knee or hip replacement over 5 years. Dichotomous logistic regression models assessed the relationship of comorbidities with KL progression and joint replacement while controlling for gender, age and BMI. Data from 384 non-obese participants were analyzed, 151 with hip OA and 254 with knee OA. At 5 years, cardiovascular diseases (CVD) were significantly associated with the 5-year KL change in both knee (OR = 2.56 (1.14–5.78), p = 0.02) and hip OA (OR = 3.45 (1.06–11.17), p = 0.04). No significant relationship was found between any type of comorbidities and knee or hip arthroplasty. This 5-year association between CVD and radiological progression of knee and hip OA in non-obese participants argue for an integrated management of CVD in knee and hip OA non-obese patients.
Safety and Impact of Anti-COVID-19 Vaccines in Psoriatic Patients Treated with Biologics: A Real Life Experience
Authors: Skroza Nevena , Bernardini Nicoletta , Tolino Ersilia , Proietti Ilaria , Mambrin Alessandra , Marchesiello Anna , Marraffa Federica , Rossi Giovanni , Volpe Salvatore , Potenza Concetta
Published: July 2021

Since all clinical trials conducted during the development of anti-COVID-19 vaccines have adopted among the exclusion criteria the presence of immunodepression or immunomodulating therapy, to date, the effects of vaccination against the new coronavirus 2 in people under such conditions have yet to be clearly defined. The primary objective of the study is to assess the safety of treatment with biotechnological drugs in patients suffering from moderate–severe psoriasis and subjected to the prophylactic vaccination against SARS-Cov-2. Additionally, the secondary objective of the research is to investigate the existence of a possible impact of anti-COVID-19 vaccination on the natural chronic-relapsing course and the severity of the psoriatic disease. The study included 436 patients with moderate–severe psoriasis, both male and female, in treatment with biologics. The data were collected using the direct interview method. A reduction of 74.13% of average Psoriasis Area Severity Index (PASI )compared to baseline (T0) was found in all subjects; this does not differ significantly from the group that underwent vaccination (73.4%). Moreover; at the end of the study, neither mild nor severe adverse events (ADR) were observed among them. In conclusion, biotechnological drugs used in the management of patients with moderate–severe psoriasis demonstrate a high safety profile also in subjects immunized against SARS-Cov-2.
Selective Segmental Pulmonary Angiography: Anatomical, Technical and Safety Aspects of a Must-Learn Technique in Times of Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension
Authors: Velázquez Maite , Maneiro Nicolás , Lareo Ana , Albarrán Agustín , Huertas Sergio , Olazábal Allende P. , Delgado Juan F. , Alonso Sergio , Sarnago Fernando , García Tejada Julio , Arribas Fernando , Escribano Pilar
Published: July 2021

With the advent of balloon pulmonary angioplasty (BPA) for non-surgical chronic thromboembolic pulmonary hypertension (CTEPH) patients, there is renewed interest in the pulmonary angiography technique. This technique is still the standard imaging modality to confirm CTEPH, which, in addition, helps to determine the most appropriate treatment. Furthermore, learning this technique fulfills two main purposes: to identify BPA candidates and to provide the operator with the catheter handling needed to perform BPA. Operators interested in performing BPA must learn not only the pulmonary arteries’ anatomy, but also which are the best angiographic projections and the most suitable catheters to canalize and display each segmental branch. Unfortunately, this information is scarce in the literature. With this goal, learning the diagnostic pulmonary angiography technique can be a first step on the way to perform BPA. Although there are descriptions on how to perform a pulmonary angiography with balloon-tipped catheters and the digital subtraction technique, this technique does not provide operators with the catheter knowledge and manual skill needed to cannulate each segmental branch. In contrast, learning the conventional selective segmental pulmonary angiography (SSPA) technique provides the operator with this knowledge and skills. In this review, based on the experience of the authors, we describe the pulmonary arteries’ anatomy and detail the practical aspects of the SSPA procedure, with the aim of providing operators with the anatomical and technical knowledge needed to perform BPA. We also summarize the contemporary complications of SSPA in CTEPH patients at a reference center.
Coronavirus Pneumonia: Outcomes and Characteristics of Patients in an Inner-City Area after 3 Months of Infection
Authors: Diaz-Fuentes Gilda , Roa-Gomez Gabriella , Reyes Olga , Singhal Ravish , Venkatram Sindhaghatta
Published: July 2021

Background: The morbidity and long term pulmonary consequences of COVID-19 infection continue to unfold as we learn and follow survivors of this disease. We report radiological evolution and pulmonary function findings in those patients. Methods: This was a retrospective cohort study of adult patients referred to the post-acute COVID-19 pulmonary clinic after a diagnosis of COVID-19 pneumonia. The study period was after the initial peak of the pandemic in New York City, from June to December 2020. Results: 111 patients were included. The average interval time between COVID-19 pneumonia and initial clinic evaluation was 12 weeks. 48.2% of patients had moderate and 22.3% had severe infection. Dyspnea and cough was the most common respiratory symptoms post infection. Radiographic abnormalities improved in majority of patients with ground glass opacities been the common residual abnormal finding. Restrictive airway disease and decreased diffusion capacity were the most common findings in pulmonary function test. Conclusion: Our study suggests the needs for close and serial monitoring of functional and radiological abnormalities during the post COVID-19 period. Considering that many of the clinical-radiological and functional abnormalities are reversible, we suggest a “wait and watch“approach to avoid unnecessary invasive work up.
Prognosis of Atrial Fibrillation Patients Undergoing PCI According to Anticoagulants and Antiplatelet Agents
Authors: Yoon Gwang-Seok , Kim Sun-Hwa , Kang Si-Hyuck , Yoon Chang-Hwan , Cho Young-Seok , Youn Tae-Jin , Chae In-Ho
Published: July 2021

There are limited data evaluating conformation of antithrombotic therapy usage to the guideline recommendations. We investigated clinical trends and prognoses of patients with atrial fibrillation (AF) according to anticoagulants and antiplatelet agents beyond 1 year after percutaneous coronary intervention (PCI). We analyzed the records of patients with AF who underwent PCI using the Korean National Health Insurance Service database. The primary endpoint was a composite of major adverse cardiac events (MACE). The safety outcome was bleeding complications. Of 4193 participants, 81.6% received antiplatelet therapy, whereas 27.3% had oral anticoagulant (OAC)-based therapy at 18 months after PCI. The dominant therapy was dual antiplatelet therapy (37.2%), and only 3.3% of participants had OAC monotherapy. At the 1-year follow-up, the incidence of MACE was significantly lower among those receiving a combination of OAC and single antiplatelet therapy (SAPT) than among those receiving OAC monotherapy (4.78% vs. 9.42%, p = 0.017). Bleeding complication events (5.01% vs. 5.80%, p = 0.587) did not differ between the groups. In clinical practice, most patients with AF who underwent PCI continued to receive antiplatelet agents beyond 1-year post-PCI. OAC with SAPT seemed to be more effective than OAC monotherapy, without a difference in safety.
Endoscopic Double Stenting for the Management of Combined Malignant Biliary and Duodenal Obstruction
Authors: Takeda Tsuyoshi , Sasaki Takashi , Okamoto Takeshi , Sasahira Naoki
Published: July 2021

Periampullary cancers are often diagnosed at advanced stages and can cause both biliary and duodenal obstruction. As these two obstructions reduce patients’ performance status and quality of life, appropriate management of the disease is important. Combined malignant biliary and duodenal obstruction is classified according to the location and timing of the duodenal obstruction, which also affect treatment options. Traditionally, surgical bypass (gastrojejunostomy and hepaticojejunostomy) has been performed for the treatment of unresectable periampullary cancer. However, it has recently been substituted by less invasive endoscopic procedures due to its high morbidity and mortality. Thus, endoscopic double stenting (transpapillary stenting and enteral stenting) has become the current standard of care. Limitations of transpapillary stenting include its technical difficulty and the risk of duodenal-biliary reflux. Recently, endoscopic ultrasound-guided procedures have emerged as a novel platform and have been increasingly utilized in the management of biliary and duodenal obstruction. As the prognosis of periampullary cancer has improved due to recent advances in chemotherapy, treatment strategies for biliary and duodenal obstruction are becoming more important. In this article, we review the treatment strategies for combined malignant biliary and duodenal obstruction based on the latest evidence.
ADAM 17 and Epithelial-to-Mesenchymal Transition: The Evolving Story and Its Link to Fibrosis and Cancer
Authors: Sisto Margherita , Ribatti Domenico , Lisi Sabrina
Published: July 2021

For decades, metalloproteinase 17 (ADAM17) has been the goal of wide investigation. Since its discovery as the tumour necrosis factor-α convertase, it has been studied as the main drug target, especially in the context of inflammatory conditions and tumour. In fact, evidence is mounting to support a key role of ADAM17 in the induction of the proliferation, migration and progression of tumour cells and the trigger of the pro-fibrotic process during chronic inflammatory conditions; this occurs, probably, through the activation of epithelial-to-mesenchymal transition (EMT). EMT is a central morphologic conversion that occurs in adults during wound healing, tumour progression and organ fibrosis. EMT is characterised by the disassembly of cell–cell contacts, remodelling of the actin cytoskeleton and separation of cells, and generates fibroblast-like cells that express mesenchymal markers and have migratory properties. This transition is characterised by loss of epithelial proteins such as E-cadherin and the acquisition of new mesenchymal markers, including vimentin and a-smooth muscle actin. The present review discusses the current understanding of molecular mechanisms involved in ADAM17-dependent EMT in order to individuate innovative therapeutic strategies using ADAM17-related pathways.
An Efficient Methodology towards Mechanical Characterization and Modelling of 18Ni300 AMed Steel in Extreme Loading and Temperature Conditions for Metal Cutting Applications
Authors: Silva Tiago E. F. , Gregório Afonso V. L. , de Jesus Abílio M. P. , Rosa Pedro A. R.
Published: July 2021

A thorough control of the machining operations is essential to ensure the successful post-processing of additively manufactured components, which can be assessed through machinability tests endowed with numerical simulation of the metal cutting process. However, to accurately depict the complex metal cutting mechanism, it is not only necessary to develop robust numerical models but also to properly characterize the material behavior, which can be a long-winded process, especially for state-of-stress sensitive materials. In this paper, an efficient mechanical characterization methodology has been developed through the usage of both direct and inverse calibration procedures. Apart from the typical axisymmetric specimens (such as those used in compression and tensile tests), plane strain specimens have been applied in the constitutive law calibration accounting for plastic and damage behaviors. Orthogonal cutting experiments allowed the validation of the implemented numerical model for simulation of the metal cutting processes. Moreover, the numerical simulation of an industrial machining operation (longitudinal cylindrical turning) revealed a very reasonably prediction of cutting forces and chip morphology, which is crucial for the identification of favorable cutting scenarios for difficult-to-cut materials.
Turning Scientific Knowledge into Regulation: Effective Measures for Noise Mitigation of Pile Driving
Authors: Juretzek Carina , Schmidt Ben , Boethling Maria
Published: July 2021

Pile driving is one of the most intense anthropogenic noise sources in the marine environment. Each foundation pile may require up to a several thousand strokes of high hammer energy to be driven to the embedded depth. Scientific evidence shows that effects on the marine environment have to be anticipated if mitigation measures are not applied. Effective mitigation measures to prevent and reduce the impact of pile driving noise should therefore be part of regulation. The role of regulators is to demonstrate and assess the applicability, efficiency and effectiveness of noise mitigation measures. This requires both, scientific knowledge on noise impacts and the consideration of normative aspects of noise mitigation. The establishment of mitigation procedures in plans and approvals granted by regulatory agencies includes several stages. Here, we outline a step-wise approach in which most of the actions described may be performed simultaneously. Potential measures include the appropriate maritime spatial planning to avoid conflicts with nature conservation, site development for offshore wind farms to avoid undesirable activities in time and space, coordination of activities to avoid cumulative effects, and the application of technical noise abatement systems to reduce noise at the source. To increase the acceptance of noise mitigation applications, technical measures should fulfil a number of requirements: (a) they are applicable and affordable, (b) they are state-of-the-art or at least advanced in development, (c) their efficiency can be assessed with standardised procedures. In this study, the efficiency of noise mitigation applied recently in offshore wind farm construction projects in the German North Sea is explained and discussed with regard to the regulation framework, including the technical abatement of impulsive pile driving noise.
Maintaining the Quality and Storage Life of Button Mushrooms (Agaricus bisporus) with Gum, Agar, Sodium Alginate, Egg White Protein, and Lecithin Coating
Authors: Cavusoglu Seyda , Uzun Yusuf , Yilmaz Nurettin , Ercisli Sezai , Eren Erkan , Ekiert Halina , Elansary Hosam O. , Szopa Agnieszka
Published: July 2021

Button mushrooms have a very short shelf life after harvesting and are sensitive to mechanical damage and browning. This can be a severe problem in enlarging the market and the long-distance exportation of this product. In this respect, edible coatings could be an alternative treatment to extend the shelf life of button mushrooms, maintaining their quality during long-term storage. The aim of this study was to investigate the impact of gum, agar, sodium alginate, egg white protein, and lecithin on the postharvest weight loss, color, browning, respiration rate, ethylene production, and storage life of button mushrooms. The results showed that the above-mentioned edible coatings are a promising way to extend the life and maintain the quality of button mushrooms. Significant differences (p < 0.05) were observed between the control and edible coating-treated samples in all parameters. Sodium alginate and gum were more effective in preventing weight loss, coloring, and browning than other edible coatings. On the other hand, the respiration rate and ethylene production were more suppressed by the agar and lecithin coatings compared to the others. In conclusion, it can be recommended that the above-mentioned edible coatings could be used as novel coatings in commercial treatments for maintaining the quality of button mushrooms during a long-term storage period.
First Documentation of Life Cycle Completion of the Alien Rust Pathogen Melampsoridium hiratsukanum in the Eastern Alps Proves Its Successful Establishment in This Mountain Range
Authors: Moricca Salvatore , Benigno Alessandra , Oliveira Longa Claudia Maria , Cacciola Santa Olga , Maresi Giorgio
Published: July 2021

Melampsoridium hiratsukanum is an alien rust fungus which has spread pervasively throughout several European countries following introduction into North Europe at the end of the 20th century. The authenticity of several records of the Melampsoridium species infecting alder (Alnus spp.) in the northern hemisphere is questionable, due to the misidentification and confusion that surround many of the older reports. Given this complicated taxonomic history, and since a M. hiratsukanum-like rust is strongly impacting Alnus incana stands in the Alps, probably affecting the bank protection role of this species along rivers, the unambiguous identification of this pathogen was a pressing epidemiological and ecological issue. In this study, field surveys, light (LM) and scanning electron microscopy (SEM), and molecular characterization were put together in an attempt to solve the conundrum. Field monitoring data, LM and SEM analyses of key taxonomic traits (length of ostiolar cells of uredinium, uredinio-spore shape and size, spore echinulation, number and position of germ pores) and ITS-rDNA sequence-based identification, convergently and unambiguously connected the rust that is causing the current epidemic to the non-native M. hiratsukanum. We documented the completion of the M. hiratsukanum life cycle on its two taxonomically unrelated broadleaf/conifer hosts. This is the first report of M. hiratsukanum from naturally infected Larix decidua in Europe.
Digital Marketing Effects of Clubhouse on Crowdfunding in the Context of COVID-19
Authors: Konhäusner Peter , Seidentopf Robert
Published: July 2021

In the marketing mix, promotion is mentioned as using the communication channels available to present and market the product or service at hand. In recent years, social media has risen as an influential marketing communication channel in digital space. Apart from end-to-end direct messengers and video communication in times of the COVID-19 pandemic, the social media channel Clubhouse offers an audio-only experience. The current research lacks analysis of the potential influence of the hyped social network. Due to the novelty of the channel and the absence of text messages as well as visual stimuli, questions regarding the impact that usage of this social media channel might have on crowdfunding, a means of rising popularity in alternative financing, have arisen. The study builds upon the media richness theory of Daft and Lengel as well as the channel expansion theory of Carlson and Zmud. Besides literature research, explorative expert interview analyses were applied to answer the research question at hand. The main findings include different approaches to foster the opportunities of Clubhouse for marketing crowdfunding campaigns in line with insights about the user group of Clubhouse as well as development options for the platform.
Factor Endowments, Economic Integration, Round-Tripping, and Inward FDI: Evidence from the Baltic Economies
Authors: Cieślik Andrzej , Gurshev Oleg
Published: July 2021

This paper studies the location choice of foreign multinational firms in the Baltic economies of Estonia, Latvia, and Lithuania using a knowledge-and-physical capital model across 2004–2017. We used the Bayesian model averaging estimation method to investigate a set of possible factors that drive inward FDI. Our analysis demonstrates that factor endowments play a dominant role in driving vertical foreign direct investment, while external market barriers generate “tariff-jumping” FDI. Our analysis quantifies the effects of round-trip FDI, European integration, and external bilateral free trade agreements vis-à-vis inward FDI in the Baltics.
Identifying and Setting Linear Water Space Priorities in Co-Urbanized Area Based on Multiple Levels and Multiple Ecosystem Services
Authors: Shen Jiake , Wang Yuncai , Guo Xiaolu
Published: July 2021

Due to intense anthropogenic impacts, river networks in co-urbanized areas are severely degraded and fragmented, and their ability to supply multiple ecosystem services is greatly reduced. This study aimed to provide a novel technical approach to identify spatial priorities for complex and special linear water spaces in a co-urbanized area. This approach fully considers the features of river networks with multiple levels and multiple functions. We first identified two spatial configurations of river networks based on the river density: river cluster patches and river corridors, which were each divided into four spatial levels. We then assessed and mapped the multiple ecosystem services provided by each river level through a coupling evaluation model. Finally, based on the evaluation results and spatial clustering analysis, we identified priorities of linear water spaces using six priority grades. This priority identification method based on multiple levels and multiple ecosystem services of linear water spaces shows how a holistic catchment perspective can be applied to the practice of integrated river management in co-urbanized areas. Selecting conservation strategies for linear water spaces on the basis of their structural level and ecological contribution is a more targeted measure.
Association of Nonalcoholic Hepatic Fibrosis with Body Composition in Female and Male Psoriasis Patients
Authors: Brunner Kinga , Oláh Péter , Moezzi Mehdi , Pár Gabriella , Vincze Áron , Breitenbach Zita , Gyulai Rolland
Published: July 2021

Psoriasis has been associated with increased frequency of hepatic diseases. Psoriasis severity, obesity, insulin resistance, aspartate aminotransferase level, platelet count, and alcohol use are significant predictors for advanced fibrosis in psoriasis patients. Although psoriasis patients also present body composition changes (e.g., higher overall body fat, visceral fat and sarcopenia), and these have recently been reported as risk factors for hepatic fibrosis, to date, body composition has not been prospectively investigated in psoriasis in the context of liver fibrosis. In this study anthropometric assessment (body weight and body mass index (BMI)), body composition analysis (body fat%, visceral fat scores and muscle mass%), and liver stiffness measurements (using transient elastography [TE]) were done in 52 psoriasis patients undergoing methotrexate therapy. Fourteen patients (26.9%) had advanced (F3–F4) liver fibrosis. There was no correlation between the patients’ liver stiffness values and the cumulative MTX doses. On the other hand, patients with higher BMI values, total body fat% and visceral fat scores were significantly more likely to present with higher hepatic stiffness values. BMI was a significant predictor of hepatic fibrosis in both genders. In males, body fat% (R = 0.578, p = 0.002) and, especially, visceral fat scores (R = 0.716, p < 0.001) had statistically significant correlation with stiffness scores, while in females only visceral fat scores were statistically significant predictors of the liver stiffness values (R = 0.452, p = 0.023), and body fat% was not (R = 0.187, p = 0.382). Our results suggest that anthropometric data should be assessed differently in female and male psoriasis patients when evaluating liver fibrosis risk.
A Study on the Flow Resistance of Fluids Flowing in the Engine Oil-Cooler Chosen
Authors: Derbiszewski Bogdan , Wozniak Marek , Grala Lukasz , Waleciak Michal , Hryshchuk Maksym , Siczek Krzysztof , Obraniak Andrzej , Kubiak Przemyslaw
Published: July 2021

Oil-coolers are necessary components in high performance diesel engines. The heat removed by the cooler is a component in the total heat rejection via the engine coolant. Oil-cooler absorbs the heat rejected during the piston cooling and engine rubbing friction power loss. During flows of both coolant and engine oil via the oil-cooler, some flow resistances occur. The aim of the study is to determine values of the flow resistance coefficient for oil going through the cooler at various temperatures. The test stand was developed to determine time needed to empty tanks from liquids flowing through oil-cooler. The flow model was elaborated to study the mentioned flow resistance coefficient with respect to changing liquid temperature. The 20 °C increase in liquid temperature resulted in a flow resistance coefficient decrease of 30% for coolant and of the much more for engine oil. It was found that better results would be achieved with flows forced by means of pumps instead of using gravitational forces on the test stand.
Bactericidal and Fungistatic Properties of LDPE Modified with a Biocide Containing Metal Nanoparticles
Authors: Janczak Katarzyna , Kosmalska Daria , Kaczor Daniel , Raszkowska-Kaczor Aneta , Wedderburn Lauren , Malinowski Rafał
Published: July 2021

The aim of this study was to ascertain whether the combined action of metal nanoparticles (silver, copper, zinc oxide, iron oxide) would ensure the appropriate biocidal properties oflow-density polyethylene (LDPE) against pathogenic microorganisms. According to the research hypothesis, appropriately selected concentrations of the applied metal nanoparticles allow for a high level of biocidal activity of polymeric materials against both model and pathogenic bacterial strains (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Legionella pneumophila, Salmonella enterica subsp. enterica) and fungi (Aspergillus brasiliensis, Saccharomyces cerevisiae, Candida albicans, Penicilium expansum), whilst ensuring the safety of use due to the lack of migration of particles to the surrounding environment. Studies have shown that adding 4% of a biocide containing Ag, Cu, ZnO, and Fe2O3 nanoparticles is the most optimal solution to reduce the number of S. aureus, S. enterica and P. aeruginosa by over 99%. The lowest effectiveness was observed against L. pneumophila bacteria. As for E. coli, a higher biocide content did not significantly increase the antibacterial activity. The results showed a high efficiency of the applied biocide at a concentration of 2% against fungal strains. The high efficiency of the obtained biocidal results was influenced by the uniform dispersion of nanoparticles in the material and their low degree of agglomeration. Furthermore, a slight migration of components to the environment is the basis for further research in the field of the application of the developed materials in industry.
Failure Analysis and Prevention of Extraction Column for Methyl Methacrylate Production: Application of the ‘Safety Design’ Concept
Authors: Wang Sheng-Hui , Gong Yi , Tong Qi , Yang Xiao-Lei , Shen Jia-Hao , Yang Zhen-Guo
Published: July 2021

To ensure safety and prevent failure of engineering equipment throughout its lifespan, the concept of ‘Safety Design’ is proposed, which covers all the cradle-to-grave phases of engineering equipment, considers at least ten essential factors of failure causes, and conducts root cause analysis at three different scales, in order to proactively control the safety risks before the occurrence of failure rather than passively conduct the remedial measures after failure. Herein, in order to demonstrate how to implement this effective and efficient concept in engineering practice, a case study of failure analysis and prevention is addressed on the extraction column in the production line for methyl methacrylate. Based on the analysis results, the causes were finally determined to be all derived from the stages before operation, including inappropriate design, limited quality inspection of fabrication and installation. Pertinent countermeasures were then proposed from the ‘Safety Design’ point of view, which would not only solve the failure problem for this sole equipment but also contribute to safety risk control of other engineering equipment before operation.
Low Cycle Fatigue Characteristics of Oxygen-Free Copper for Electric Power Equipment
Authors: Tanaka Takuma , Sugioka Togo , Kobayashi Tatsuya , Shohji Ikuo , Shimada Yuya , Watanabe Hiromitsu , Kamakoshi Yuichiro
Published: July 2021

The effect of heat treatment on tensile and low cycle fatigue properties of the oxygen-free copper for electric power equipment was investigated. The heat treatment at 850 °C for 20 min, which corresponds to the vacuum brazing process, caused the grain growth and relaxation of strain by recrystallization, and thus, the residual stress in the oxygen-free copper was reduced. The tensile strength and 0.2% proof stress were decreased, and elongation was increased by the heat treatment accompanying recrystallization. The plastic strain in the heat-treated specimen was increased compared with that in the untreated specimen under the same stress amplitude condition, and thus, the low cycle fatigue life of the oxygen-free copper was degraded by the heat treatment. Striation was observed in the crack initiation area of the fractured surface in the case of the stress amplitude less than 100 MPa regardless of the presence of the heat treatment. With an increase in the stress amplitude, the river pattern and the quasicleavage fracture were mainly observed in the fracture surfaces of the untreated specimens, and they were observed with striations in the fracture surfaces of the heat-treated ones. The result of the electron backscattered diffraction (EBSD) analysis showed that the grain reference orientation deviation (GROD) map was confirmed to be effective to investigate the fatigue damage degree in the grain by low cycle fatigue. In addition, the EBSD analysis revealed that the grains were deformed, and the GROD value reached approximately 28° in the fractured areas of heat-treated specimens after the low cycle fatigue test.
Mechanical Compound Fault Analysis Method Based on Shift Invariant Dictionary Learning and Improved FastICA Algorithm
Authors: Yuan Haodong , Wu Nailong , Chen Xinyuan
Published: July 2021

For mechanical compound fault, it is of great significance to employ the vibration signal of a single-channel compound fault to analyze and realize the separation of multiple fault sources, which is essentially the problem of single-channel blind source separation. Shift invariant K-means singular value decomposition (shift invariant K-SVD) dictionary learning is suitable to extract the periodic and repeated fault features of a rotating machinery fault, hence in this article a single-channel compound fault analysis method is put forward which combines shift invariant K-SVD with improved fast independent component analysis (improved FastICA) algorithm. Firstly, based on single-channel compound fault signal, the shift invariant K-SVD algorithm can be used for learning multiple latent components that can be constructed as a virtual multi-channel signal. Then the improved FastICA algorithm is utilized to realize the separation of multiple fault source signals. With regard to the FastICA algorithm, the third-order convergence Newton iteration method is adopted to improve convergence speed. Moreover, in order to address the problem that FastICA is very sensitive to initialization, a steepest descent method can be applied. The experimental analysis of the compound fault of rolling bearing verifies that the presented method is effective to separate multiple fault source signals and the improved FastICA algorithm can increase convergence rate and overcome the problem of sensitivity to initialization.
Grasp Point Optimization and Leakage-Compliant Dimensioning of Energy-Efficient Vacuum-Based Gripping Systems
Authors: Gabriel Felix , Baars Susanna , Römer Martin , Dröder Klaus
Published: July 2021

Vacuum-based handling, used in many applications and industries, offers great flexibility and fast handling processes. However, due to significant energy conversion losses from electrical energy to the useable suction flow, vacuum-based handling is highly energy-inefficient. In preliminary work, we showed that our grasp optimization method offers the potential to save at least 50% of energy by a targeted placement of individual suction cups on the part to be handled. By considering the leakage between gripper and object, this paper aims to extend the grasp optimization method by predicting the effective compressed air consumption depending on object surface roughness, gripper diameter and gripper count. Through balancing of the target pressure difference and the leakage tolerance in combination with the gripper count and gripper diameter, significant reductions of the compressed air, use and therefore the overall energy consumption, can be achieved. With knowledge about the gripper-specific leakage behavior, in the future it will be straightforward for system integrators to minimize the need for oversizing due to process-related uncertainties and therefore to provide application-specific and energy-optimized handling solutions to their customers.
Improving DFT-Based Image Watermarking Using Particle Swarm Optimization Algorithm
Authors: Cedillo-Hernandez Manuel , Cedillo-Hernandez Antonio , Garcia-Ugalde Francisco J.
Published: July 2021

Robust digital image watermarking is an information security technique that has been widely used to solve several issues related mainly with copyright protection as well as ownership authentication. In general terms, robust watermarking conceals a small signal called a “watermark” in a host image in a form imperceptible to human vision. The efficiency of conventional robust watermarking based on frequency domain depend directly on the results of performance in terms of robustness and imperceptibility. According to the application scenario and the image dataset, it is common practice to adjust the key parameters used by robust watermarking methods in an experimental form; however, this manual adjustment may involve exhaustive tasks and at the same time be a drawback in practical scenarios. In recent years, several optimization techniques have been adopted by robust watermarking to allowing adjusting in an automatic form its key operation parameters, improving thus its performance. In this context, this paper proposes an improved robust watermarking algorithm in discrete Fourier transform via spread spectrum, optimizing the key operation parameters, particularly the amounts of bands and coefficients of frequency as well as the watermark strength factor using particle swarm optimization in conjunction with visual information fidelity and bit correct rate criteria. Experimental results obtained in this research show improved robustness against common signal processing and geometric distortions, preserving a high visual quality in color images. Performance comparison with conventional discrete Fourier transform proposal is provided, as well as with the current state-of-the-art of particle swarm optimization applied to image watermarking.
Investigation of Backfilling Step Effects on Stope Stability
Authors: Xu Huawei , Apel Derek B. , Wang Jun , Wei Chong , Pourrahimian Yashar
Published: July 2021

Cemented rock fill (CRF) is commonly used in cut-and-fill stoping operations in underground mining. This allows for the maximum recovery of ore. Backfilling can improve stope stability in underground workings and then improve ground stability of the whole mine site. However, backfilling step scenarios vary from site to site. This paper presents the investigation of five different backfilling step scenarios and their impacts on the stability of stopes at four different mining levels. A comprehensive comparison of displacements, major principal stress, and Stress Concentration Factor (SCF) was conducted. The results show that different backfilling step scenarios have little influence on the final displacement for displacement in the stopes. Among the five backfilling scenarios, the major principal stress and stress concentration factor (SCF) have almost the same final results. The backfilling scenario SCN-1 is the optimum option among these five backfilling scenarios. It can immediately prevent the increase of the displacement and reduce the sidewall stress concentration, thereby preventing possible failures. Using the same strength of CRF can achieve the same effects among the four mining levels. Applying backfilling CRF of the same strength at different mining depths is acceptable and feasible to improve the stability of the stopes.