Main Problems Research Articles

Anticancer activity of synthesized 5-benzyl juglone on selected human cancer cell lines.

Cancer is a malignant disease that causes millions of deaths each year worldwide. As one of the cancer therapeutic strategies, chemotherapy is a means to destroy rapidly dividing cells. The main problem with cancer chemotherapy is the lack of selectivity of conventional chemotherapeutic drugs, leading to toxicity towards normal cells. Therefore, the discovery of anticancer agents with selectivity for fast-growing cancer cells was desirable. In this study, we report the synthesis and identification of the novel 5-benzyl juglone as a potential anticancer agent with selectivity toward certain cancer cell lines. An efficient synthetic method for 5-benzyl juglone has been established. The proliferation of cancer cell lines and a normal cell line treated by the target compound were studied using an MTT assay. In addition, the cell cycle arrest and apoptosis were determined by flow cytometry. Based on the Diels-Alder (D-A) reaction between 3,6-dimethoxy benzyne intermediate with furan, further acid-catalyzed intramolecular rearrangement and CAN-mediated oxidation, a convenient synthesis of 5-benzyl juglone has been achieved with high overall yield. The results from in vitro biological evaluation indicated that the juglone derivative exhibited potent antiproliferative activity against HCT-15 human colorectal cancer cells with an IC50 value of 12.27 μM. It exerted high inhibitory activity toward MCF-7 human breast cancer cells and, to a much lesser extent, to corresponding MCF-10A human breast epithelial normal cells with the IC50 ratio (IC50 in MCF-7 divided by IC50 in MCF-10A) of 0.62. The mechanistic investigations indicated that 5-benzyl juglone could induce cell cycle arrest at the G0/G1 phase and promote apoptosis of HCT-15 cells. The apoptotic effects possibly also contributed to its higher selectivity toward cancer cells than normal cell lines.

Mesenchymal Stem Cells-Conditioned Medium; An Effective Cell-Free Therapeutic Option for in vitro Maturation of Oocytes.

Infertility is a major reproductive health issue worldwide. One of the main problems in infertile women is the failure to generate or release a mature egg. Therefore, the development of new technologies for in vitro generation or induction of mature oocytes can improve various ART procedures. Recently, stem cell-based therapy has opened a new window for several pathological complications. Mesenchymal stem cells (MSCs) are multipotent stem cells with the capacity to self-renew and differentiate into the mesodermal lineage. MSCs contain various bioactive molecules which are involved in the regulation of key biological processes. They can secret multiple paracrine factors, such as VEGF, IGF, HGF, EGF, and FGF to stimulate egg maturation. Although MSCs represent a promising source for cell therapy, the potential risk of tumor development reduces their clinical applications. Recent studies have suggested that the supernatant or conditioned medium of MSCs also contains similar components and regulates the oocyte behavior. The MSC-conditioned medium can eliminate the safety concerns associated with MSC transplantation and avoid rejection problems. Although MSC and MSC-CM could improve oocyte quality, ovarian function, and fertility, these improvements have not yet been demonstrated in clinical trials in humans. Hereby, we summarized recent research findings of MSCs-derived conditioned medium in in vitro development of immature oocytes.

Patent Technology of Shipborne Stabilized Platform

Background: When a ship is sailing or operating at sea, it is unavoidable to produce sixdegrees- of-freedom movements of rolling, pitching, and yawing under the action of sea wind and waves, which seriously impacts the operation of precision equipment on the ship and the safety of personnel. The ship-borne stabilized platform can isolate the ship's motion and eliminate the impact of sea waves on the personnel and equipment on it to a large extent. With the increasing demand for ship surfaces in marine fields, such as navigation equipment, military facilities, and sea condition simulation, there is an urgent need to study ship-borne platforms with high stability and efficiency to isolate swaying and ensure ship performance. Objective: This study aims to analyse the patents and summarize the characteristics and existing problems of the shipborne platform to provide a reference for the future development of the shipborne stabilized platform. Methods: Various representative patents related to shipborne stabilized platforms and multi-DOF platforms were researched in this study. Results: Through the analysis and comparison of patent technology, the main problems existing in the structure and design principle of the existing shipborne stabilized platform are summarized, and the development trend and direction of the shipborne stabilized platform are discussed. Conclusion: Shipborne stabilization is highly significant in isolating the ship's motion. At present, the ship-borne stabilized platform has produced six degrees of freedom of movement, but due to the improvement of control response requirements, the structure of the platform needs to be further improved. With the development of test technology toward intelligent and big data-driven technology, the shipborne stabilized platform is moving toward cloud computing and large-scale testing.

Recent Patents on Rolling Bearing Lubrication Device

Background: Rolling bearings are the core components of mechanical equipment. Lubrication plays an important role in the operating performance of rolling bearings. The research on rolling bearing lubrication devices is beneficial to making the bearings obtain the characteristics which is suitable for the working conditions and improving the bearing's service life. Compared with the traditional lubrication devices, the new ones provide assistance to various bearings, solving many problems. Objective: To review the latest research on rolling bearing lubrication devices, analyze their solutions to rolling bearing lubrication problems, and discuss their advantages and disadvantages for the reference of scholars and engineers. Methods: The representative patents related to rolling bearing lubrication devices are reviewed according to the lubrication method of bearings, including oil lubrication, grease lubrication and solid lubrication. Oil lubrication includes oil mist lubrication, oil-air lubrication, jet lubrication, under ring lubrication and immersion oil lubrication, etc. Grease lubrication includes external and internal lubrication methods. The working principle and characteristics are explained by analyzing the structure of bearing lubrication devices. Results: By comparing different types of rolling bearing lubrication devices, the main problems of the current lubrication devices are summarized and analyzed. The future development of rolling bearing lubrication devices are prospected. Conclusion: The improvement of rolling bearing lubrication devices is conducive to developing bearing lubrication technology. Advanced mechanical equipments require the rolling bearing lubrication devices to have a simple structure, intelligence, and are easy to be installed.

Effect of sowing date of quinoa (Chenopodium quinoa) mother plants on germination of their seeds

Quinoa production in Israel has great agricultural potential as a dual-purpose plant for grains and as a fodder crop. One of the main problems in growing quinoa in Israel is the low germination percentage of seeds from local production. This might be due to non-optimal seed production for growers. Thus, our main objective was to examine the effect of mother plant sowing dates on the germination parameters of quinoa seeds. Sowing date of quinoa mother plants affected the germination percentage and quality of the seeds. Mother plants sown during July-October produced more viable seeds than mother plants sown in November-January. This could be due to the prevailing hot temperatures during the filling phase of the developing seeds on the plant. Because the harvest date for July-October sowings is still within the rainy season in Israel, it is likely that quinoa can be grown for seed production in dry areas such as the southern Arava.

Distribution network reconfiguration utilizing the particle swarm optimization algorithm and exhaustive search methods

The load level for each period in the distribution network can be considered non-identical due to the increasing demand for loads and the bigger distribution network. The main problem in the transmission and distribution network system is power losses and voltage profiles, affecting the quality of service and operating costs. This study compares the reconfiguration of the network using exhaustive search techniques and particle swarm optimization (PSO) algorithms on the IEEE 33 bus distribution network system. The study’s results compare the study of power flow before and after network reconfiguration, which is a decrease in the value of power losses from 202.7 kW to 139.6 kW. Then voltage profile improved from 91.309% to 93.782%. The simulation results also found that this reconfiguration can improve the system voltage profile, which initially contained 21 buses outside the standard limits of IEEE Std 1159-1995 to 7 buses.

Strengthening data integrity in academic document recording with blockchain and InterPlanetary file system

A diploma is a certificate or official document given by a school or college that is useful for continuing education, applying for jobs, and assessing student intelligence. The main problem with diplomas and other academic documents is that many are forged. This study aims to develop a prototype for recording student academic data using blockchain and blockchain and InterPlanetary file system (IPFS). The research stages were conducted with system conceptualization, data modeling, smart contract development, IPFS integration, data transaction development, user interface/user experience (UI/UX) development, and system testing. A blockchain is a permanent information structure formed by data blocks that are interconnected with transaction data blocks before and after it. The transaction data for each block are encrypted using asymmetric cryptography. IPFS is a peer-to-peer network protocol for storing and sharing data in a distributed file system applying the concept of decentralization to make the manipulation more difficult. The results show that student academic data and documents were successfully stored in a blockchain network using smart contracts and IPFS. Blockchain technology, smart contracts, and IPFS strengthen the value of these documents into documents that are safe, difficult to counterfeit, and easy to trace, such that authentication and integration are better preserved.

Asymmetric multilevel interactive attention network integrating reviews for item recommendation

Recently, most studies in the field have focused on integrating reviews behind ratings to improve recommendation performance. However, two main problems remain (1) Most works use a unified data form and the same processing method to address the user and the item reviews, regardless of their essential differences. (2) Most works only adopt simple concatenation operation when constructing user-item interaction, thus ignoring the multilevel relationship between the user and the item, which may lead to suboptimal recommendation performance. In this paper, we propose a novel Asymmetric Multi-Level Interactive Attention Network (AMLIAN) integrating reviews for item recommendation. AMLIAN can predict precise ratings to help the user make better and faster decisions. Specifically, to address the essential difference between the user and the item reviews, AMLIAN uses the asymmetric network to construct user and item features using different data forms (document-level and review-level). To learn more personalized user-item interaction, the user ID and item ID and some processed features of user reviews and item reviews are respectively used for multilevel relationships. Experiments on five real-world datasets show that AMLIAN significantly outperforms state-of-the-art methods.

ICNIRP Statement on Short Wavelength Light Exposure from Indoor Artificial Sources and Human Health.

Concerns have been raised about the possibility of effects from exposure to short wavelength light (SWL), defined here as 380-550 nm, on human health. The spectral sensitivity of the human circadian timing system peaks at around 480 nm, much shorter than the peak sensitivity of daytime vision (i.e., 555 nm). Some experimental studies have demonstrated effects on the circadian timing system and on sleep from SWL exposure, especially when SWL exposure occurs in the evening or at night. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has identified a lack of consensus among public health officials regarding whether SWL from artificial sources disrupts circadian rhythm, and if so, whether SWL-disrupted circadian rhythm is associated with adverse health outcomes. Systematic reviews of studies designed to examine the effects of SWL on sleep and human health have shown conflicting results. There are many variables that can affect the outcome of these experimental studies. One of the main problems in earlier studies was the use of photometric quantities as a surrogate for SWL exposure. Additionally, the measurement of ambient light may not be an accurate measure of the amount of light impinging on the intrinsically photosensitive retinal ganglion cells, which are now known to play a major role in the human circadian timing system. Furthermore, epidemiological studies of long-term effects of chronic SWL exposure per se on human health are lacking. ICNIRP recommends that an analysis of data gaps be performed to delineate the types of studies needed, the parameters that should be addressed, and the methodology that should be applied in future studies so that a decision about the need for exposure guidelines can be made. In the meantime, ICNIRP supports some recommendations for how the quality of future studies might be improved.

Use Crumb Rubber Chips in Partial Substitution of Coarse Aggregate While Preparing Concrete

Abstract: The purpose of this experimental investigation is to examine the behaviour features of rubberized concrete, which has coarse aggregate in place of some of the tyre rubber. Over 270 million scrap tyres are thought to be produced annually. One of the main problems in India is the disposal of discarded tyres in landfills, which is the responsibility of local governments and municipalities. Because it is not biodegradable, there are serious concerns to human health, the environment, and fire. The most promising uses of tyres in engineering are as aggregates for asphalt and concrete, artificial reefs, and erosion management, aside from gasoline obtained from tyres. Concrete's characteristics could be greatly improved in a variety of ways by using recycled tyre rubber as part of the aggregate. One of the most often used building materials is concrete. Because of this, the building sector is constantly looking for new applications and uses for its products, as well as ways to improve them while keeping costs down. The reference concrete specimen is made of M30 grade concrete. Rubber chips from scrap tyres have been utilised in place of traditional coarse aggregate as coarse aggregate. This will enable the efficient and widespread handling of rubber tyre waste in addition to enabling the sustainable use of the aggregates that are already accessible to us. After separating the rubber tyre waste into coarse chips, this tyre crumb aggregate is applied in increments of 5%, 10%, or 15% to replace the coarse aggregate. In order to determine the best way to employ crumb rubber as coarse aggregate in concrete, this study assessed the workability and compressive strength of rubberized concrete

In English

Natural fibre reinforced polymer composites nowadays are considered to be attractive cheap, safe and eco-friendly materials. The main problem of such composites related to the hydrophilicity of plant fibres may be successfully solved by chemical modification of their surface. However, some characteristics of the materials may be suppressed after this procedure. Therefore, the aim of the research is to find out the impact of chemical modification of filler on thermooxidative stability, tensile and flexural strength, as well as on biodegradability of polymer composites. The novelty of this work is in the examining new materials on the basis of Si-containing epoxyurethanes and chemically treated hemp woody core (HWC). Woody core that is the side product of hemp industry requiring its apropriate utilization was exposed to mercerization with sodium hydroxide solution and to further functionalization with epoxidized soybean oil (ESO) or 3-aminopropyltriethoxysilane (APS). Raw and surface treated HWC was used as reinforcement for two types of organic-inorganic epoxyurethane matrices made from sodium silicate, polyurethane prepolymer based on polyisocyanate and castor oil, and either diglycidyl ether of bisphenol-A (DGEBA) or ESO as epoxy component. Functionalization of HWC led to better mechanical properties of composites. Compared to the corresponding materials including untreated filler, maximum increase in flexural strength (26 %) was observed for the samples with ESO-containing epoxyurethane and silanized HWC, while maximum increase in tensile strength (53 %) was revealed for the ones with DGEBA-containing epoxyurethane and oil treated HWC. Thermooxidative stability was also higher for composites reinforced with functionalized HWC. The specimens with APS-treated HWC performed the best at thermal decomposition. The values of their T50% were up to 68 °C more than those for composites with unmodified filler. At the same time, the samples based on APS- or ESO-treated HWC were the most resistant to biodegradation, which may be concluded from their smallest weight loss during soil burial test.

Methodological Problems and Strategic Goals of the Work on Creation of the Theory and Technology of New Generation Intelligent Computer Systems

The main methodological problems and strategic goals of work on creating the theory and technology of intelligent computer systems of a new generation are considered. The problems of the current state of work in the field of artificial intelligence and their causes are studied, and the need for a transition to a new generation of intelligent computer systems is substantiated. The basic principles underlying such systems, as well as the corresponding complex technology, are presented. The transition from local automation when solving particular problems to complex automation of various areas of human activity is justified. The concept of an ecosystem of interoperable intelligent computer systems is proposed, which is the basis for complex automation. The architecture of the ecosystem, the directions of its evolution, and the classes of systems included in the ecosystem are considered.

Overview of the level of 4D BIM integration in the construction industry in Slovakia

AbstractBuilding information modeling is one of the trends in the modern construction industry. The use of 4D building information modeling in addition to 3D building information modeling improves project planning and leads to higher quality of the final product with minimal wastage of resources. In addition, 4D building information modeling allows creating visual effects that can be shown to clients before construction begins. The study describes the ways in which 4D building information modeling can be used, as well as some of the notable benefits. The level of awareness of this technology and the level of its use in construction practice are also described. The final part describes the main problems and tasks of this field and possible ways to solve them.

Case-based reasoning as a measure of constitutional adjudication

AbstractCase-based reasoning has high significance in constitutional adjudication. The constitutional courts of the Kelsenian model also follow their own previous decisions to develop their own case law, even if those decisions do not bind them formally. In the course of constitutional interpretation, to build coherent and predictable case law and determine constitutional principles and standards in a consistent way are also reasonable expectations of constitutional adjudication deriving from the rule of law. The paper analyses the case law of the Hungarian Constitutional Court from this perspective, regarding the criticism of public figures in defamation cases. It takes case-based reasoning as a measure of the case law of the HCC, reveals the tendencies and highlights the main problems associated with it.

Food Waste Management on Restaurants in Jakarta

Objective: The purposes of this study were to explain restaurant’s policy on its procedure of food waste, to identify whether restaurant has policy of donating leftover food, to explore how restaurant train and communicate to their employees about restaurant waste disposal standard, and to understand what chefs consider to be the toughest challenges in reducing food waste. Theoretical Framework: The theoretical framework used by the restaurant operational control cycle and Waste Reduction Method Method: In this research the approach used is a qualitative approach. Data collection in this study are using interviews to Demi Chef to Executive Chef have managerial responsibilities in kitchen operations. The transcripts that have been made are analyzed using thematic coding so that data that was previously unsystematic or can be further simplified and grouped so that it is easier to understand better. The quotes from interviews will be used to propose the final description then eventually the differences made between the samples taken can be seen. Result: The result of the study that food waste disposal procedures, not all have separated and weighed food waste from their restaurants. Two main problems, which were their guests and their staffs. They won’t be able to control their guests and on the other hand, it was rather a tougher challenge to raise staff awareness of the importance of reducing food waste. Implications: It was important to educate business actors and all those involved in it, as well as all community about reducing food waste as what we are facing now is lack of knowledge about appropriate ways to measure food waste. Originality/Value: The results of this study contribute to the theory of waste management in hotel restaurants from a restaurant management perspective.

The Availability of Soil N, P, K, and Mustard Yield after the Application of Liquid Organic Fertilizer from Household Waste in Ultisols

Ultisols are one of the dominant soil orders in Indonesia, accounting for approximately 25% of the total land area. The main problem of this soil is high aluminum (Al) saturation with low pH and plant nutrients. The study was intended to determine the effect of liquid organic fertilizer (LOF) from household waste on the availability of N, P, K, and mustard yield in Ultisols. The research used a complete randomized design (CRD) with six concentrations of liquid organic fertilizer of household waste. The treatments were repeated four times. The treatment included control, 10, 20, 30,40, and 50 ml LOF in a liter of water. The study revealed that the liquid organic fertilizer from household waste increased 1.06 folds of total soil N and 1.04 folds of exchangeable-K compared to the control but did not affect available P. Also, soil pH was comparable among treatments. The greatest concentration of LOF (50 ml per liter of water) exhibited the highest yield of mustard, indicated by the highest fresh and dry shoot weight. In general, the study contributes to the development of eco-frindly agriculture.

Дослідження проблем синхронізації та захисту даних при реалізації багатопоточних програм

The issue of shared data usage by threads is especially relevant in modern multi-core and multiprocessor systems. The main problems of implementing multithreaded programs are race conditions, deadlocks, and thread starvation. The aim of the work is to solve the problem of thread racing in multithreaded calculations of resource-intensive tasks with parallel access to shared data using appropriate synchronization mechanisms, such as mutexes. A multithreaded algorithm for implementing a typical task of processing large data arrays with protection of the critical area in concurrent programs running on multiprocessor and multi-core systems has been developed and researched.

USING OF THE MODELS IN PRACTICE-ORIENTED EDUCATION DURING LEARNING OF PEDIATRIC DENTISTRY

Teachers of clinical departments of establishments of higher medical education are faced with the problem of practical training of students, and many methods have been proposed for its improvement.
 The purpose of the study was to consider the models of practice-oriented education that can be used
 during the teaching of pediatric therapeutic dentistry.
 One Minute Preceptor model is used by the teacher during a 1-5-minute conversation with the student to guide diagnostic and treatment processes; initially a student examines a patient, then presents the clinical case, after which the teacher manages his behavioral reactions.
 SNAPPS model (Summarize + Narrow + Analyze + Probe + Plan + Select) describes 6 stages of the clinical training. The model includes analysis of the medical history and examination methods, choice of the diagnoses for differential diagnostic, proper differential diagnosis, questions to the teacher about uncertainties, discussion of patient’s treatment plan and questions and sources related to the clinical case for independent processing.
 Within the framework of pattern recognition and reproduction model (standard cases), student talks about the main problem that worries the patient and offers his diagnosis based on key symptoms during 30 seconds. Teacher personally examines patient, makes a diagnosis or discusses why it cannot be made with certainty, and evaluates the student’s actions.
 All described models of practice-oriented learning improve the expression of reasoning without much impact on the time spent for case presentation. Pattern recognition and reproduction model is especially useful in dentistry to recognize widespread clinical cases. One Minute Preceptor model, which involves the initiative and mentoring role of the teacher, fits well for beginners, while SNAPPS model, that focused on independent work of students, for strong students.

Lyapunov-Schmidt reduction in the study of bifurcation of periodic travelling wave solutions of a perturbed (1 + 1)−dimensional dispersive long wave equation

In this paper, the Lyapunov-Schmidt reduction is used to investigate the bifurcation of periodic travelling wave solutions of a perturbed (1+1)−dimensional dispersive long wave equation. We demonstrate that the bifurcation equation corresponding to the original problem is supplied by a nonlinear system of two cubic algebraic equations. As the bifurcation parameters change, this system has only one, three, or five regular real solutions. The linear approximation of the solutions to the main problem has been discovered.

Promising aryl selenoate derivatives as antileishmanial agents and their effects on gene expression.

Leishmaniasis remains one of the main public health problems worldwide, with special incidence in the poorest populations. Selenium and its derivatives can be potent therapeutic options against protozoan parasites. In this work, 17 aryl selenoates were synthesized and screened against three species of Leishmania (Leishmania major, Leishmania amazonensis, and Leishmania infantum). Initial screening in promastigotes showed L. infantum species was more sensitive to selenoderivatives than the others. The lead Se-(2-selenocyanatoethyl) thiophene-2-carboselenoate (16) showed a half-maximal effective concentration of 3.07 µM and a selectivity index > 32.57 against L. infantum promastigotes. It was also the most effective of all 17 compounds, decreasing the infection ratio by 90% in L. infantum-infected macrophages with amastigotes at 10 µM. This aryl selenoate did not produce a hemolytic effect on human red blood cells at the studied doses (10-100 µM). Furthermore, the gene expression of infected murine macrophages related to cell death, the cell cycle, and the selenoprotein synthesis pathway in amastigotes was altered, while no changes were observed in their murine homologs, supporting the specificity of Compound 16 against the parasite. Therefore, this work reveals the possible benefits of selenoate derivatives for the treatment of leishmaniasis.