bluuebunny/crossref_metadata_2025 huggingface dataset:
Current Status of “Watch-and-Wait” Rectal Cancer Treatment in Asia-Pacific Countries
Authors: Huh Jung Wook , Maeda Kotaro , Liu Zheng , Wang Xishan , Roslani April Camilla , Lee Woo Yong
Published: January 2020

Purpose: Current acceptance of the watch-and-wait (W&W) approach by surgeons in Asia-Pacific countries is unknown. An international survey was performed to determine status of the W&W approach on behalf of the Asia-Pacific Federation of Coloproctology (APFCP).Methods: Surgeons in the APFCP completed an Institutional Review Board-approved anonymous e-survey and/or printed letters (for China) containing 19 questions regarding nonsurgical close observation in patients who achieved clinical complete response (cCR) to neoadjuvant chemoradiotherapy (nCRT).Results: Of the 417 responses, 80.8% (n = 337) supported the W&W approach and 65.5% (n = 273) treated patients who achieved cCR after nCRT. Importantly, 78% of participants (n = 326) preferred a selective W&W approach in patients with old age and medical comorbidities who achieved cCR. In regard to restaging methods after nCRT, the majority of respondents based their decision to use W&W on a combination of magnetic resonance imaging results (94.5%, n = 394) with other test results. For interval between nCRT completion and tumor response assessment, most participants used 8 weeks (n = 154, 36.9%), followed by 6 weeks (n = 127, 30.5%) and 4 weeks (n = 102, 24.5%). In response to the question of how often responders followed-up after W&W, the predominant period was every 3 months (209 participants, 50.1%) followed by every 2 months (75 participants, 18.0%). If local regrowth was found during follow-up, most participants (79.9%, n = 333) recommended radical surgery as an initial management.Conclusion: The W&W approach is supported by 80% of Asia-Pacific surgeons and is practiced at 65%, although heterogeneous hospital or society protocols are also observed. These results inform oncologists of future clinical study participation.
The effect of hydrogen on the physical properties of natural gas and the metrological characteristics of its metering systems
Authors: Stetsenko A. A. , Nedzelsky S. D. , Naumenko V. A.
Published: January 2020

Given the promise of the concept of using a mixture of hydrogen and natural gas as an energy source, studies were conducted in the following areas:

determination of the effect of hydrogen impurities on the physical properties of natural gas;
study of the effect of adding hydrogen to natural gas on the metrological characteristics of its consumption metering systems.

To solve these problems, the following was carried out:

determination of the dependence of the physical parameters of natural gas on the percentage of hydrogen in its composition:
determination of the permissible fraction (permissible concentration) of hydrogen in natural gas in modern gas transmission and gas consuming systems.
study of the effect of hydrogen additions on the metrological characteristics of measuring instruments and gas commercial metering systems.

To conduct objective research and modeling, natural gas samples having different component composition were prepared. An analysis of the physical properties of these gases was carried out — their physical parameters were calculated: adiabatic index and sound velocity, density, compressibility factor, higher calorific value and Wobbe number. Based on these samples, modeling was performed — the physical parameters of the gases were calculated by adding hydrogen at different concentrations (from 2 to 23 %).
Based on the research results, the following conclusions are made:

When hydrogen is added to natural gas in an amount of from 2 to 10 %, the physical parameters of the resulting mixture change slightly (within acceptable limits), therefore, the addition of hydrogen to natural gas in an amount of up to 10 % allows the use of existing gas transmission and gas-consuming systems without any reconstructions, improvements, changes in algorithms for calculating the physical parameters of the gas mixture and calculating (volume) volumetric flow for commercial accounting. The impact on gas meters of consumers will be within the acceptable ranges of accuracy and repeatability and, therefore, will not require the cost of updating the meters.
The addition of up to 25 % hydrogen by volume does not require a radical new technology of burners and gas transmission systems. Safety will not be compromised by adding 25 % hydrogen by volume to the natural gas network. Changes in the physical properties in the gas mixture have a number of disadvantages, but, in the aggregate, they do not pose any additional safety risk.
The addition of hydrogen in a volume of more than 25 %, as well as the use of the mixture at high pressures, requires additional research and the development of new algorithms.
Using Cuda and Blockchain Technologies to Recover an Encrypted Pdf File Password
Authors: Kvasnikov V. P. , Dudnik A. S. , Pysarchuk O. O. , Domkiv T. S.
Published: January 2020

The article presents an algorithm for using parallel computing technology using CUDA and blockchain technology to recover the password for an encrypted PDF file. The analysis and comparison of the computational speed using a graphics processor (GPU) and a central processing unit (CPU) are carried out. The testing of the implemented algorithm is carried out. A statistical analysis of the results of experimental studies is presented.
PRODUCTION OF RARE EARTH METALS IN THE INTERESTS OF DEFENSE AND THE IMPACT OF REGULATORY RESTRICTIONS ON THE INDUSTRY IN THE UNITED STATES
Authors: Izyumov D.B. , Kondratyuk E.L.
Published: January 2020

The article presents the results of the analysis of the global market of rare earth metals for the needs of the armed forces abroad. The Article also estimates the direction of development of the US legislative system in this area, as well as presents the results of comparing the levels of development of production of rare earth metals in the US and China.
Modifikasi Lempung Menjadi Adsorben dan Pemanfaatannya sebagai Penyerap Limbah Deterjen
Authors: Suarya Putu , Suirta I Wayan
Published: January 2020

ABSTRAKSelektifitas lempung alam sebagai adsorben dapat diperbaiki melalui proses modifikasi lempung dengan proses aktivasi dan interkalasi. Modifikasi lempung akan diawali dengan proses aktivasi lempung menggunakan asam sulfat, yang bertujuan untuk membersihkan permukaan dan menghomogenkan kation antarlapis dari lempung. Selanjutnya proses interkalasi surfaktan akan menjadi lebih mudah terjadi apabila kation antar lapis telah homogen. Hasil karakterisasi terhadap lempung menunjukkan bahwa lempung yang telah dimodifikasi memiliki karakter yang lebih baik dilihat dari peningkatan luas permukaan spesifik dan keasaman permukaannya. Hasil peneltiannya menunjukkan terjadi peningkatan jumlah situs aktif dari lempung alam (A0) sebesar 3,9823 x 1020 atom/gram menjadi 10,947 x 1020 atom/gram pada lempung teraktivasi asam sulfat 2 M (AA) dan pada lempung teraktivasi asam sulfat 2 M dan terinterkalasi BKC 3% (AAB) sebesar 11,320 x 1020 atom/gram. Hasil uji kemampuan adsorpsinya terhadap limbah deterjen menunjukkan bahwa pada kajian variasi waktu adsorpsi, adsorben A0 mempunyai waktu kontak optimum 15 menit sedangkan AA dan AAB sampai dengan waktu 60 menit masih menunjukkan peningkatan daya adsorpsi terhadap limbah deterjen.Kata kunci : Modifikasi, Lempung, Montmorillonit, adsorpsi, limbah deterjen.ABSTRACTSelectivity of natural clay as an adsorbent can be improved through modification of clay with activation and intercalation process. Modification of clay will be preceded by the activation process using sulfuric acid, which aims to clean the surface and homogenizes the interlayer cations of clay. Selejuynya surfactant intercalation process will become easier to occur when cations between layers have been homogeneous. The results showed that the characterization of clay that has been modified to have better characters seen from the increase in specific surface area and the acidity of the surface. The Results showed that an increase in the number of active sites of natural clay (A0) of 3.9823 x 1020 atoms / gram to 10.947 x 1020 atoms / gram on activated clays 2 M sulfuric acid (AA) and the activated clay sulfuric acid 2 M and intercalated BKC 3% (AAB) amounted to 11.320 x 1020 atoms / gram. The test results on the adsorption ability of detergent waste shows that the study of time variation of adsorption, the adsorbent A0 have optimum contact time of 15 minutes while the AA and AAB up with 60 minutes still showed an increase in the adsorption capacity of the waste detergent.Key words : Modification, clay, montmorillonite, adsorption, waste detergent
Edukasi Kesehatan Reproduksi pada Remaja untuk Menghadapi 1000 Hari Pertama Kehidupan
Authors: Desmawati Desmawati
Published: January 2020

Reproductive health education in female adolescent to face the first 1000 days of human life involving: knowledge about  270  days of pregnancy such as knowledge of pregnancy, assestment of pregnancy in health services, breast care, body and clothes hygiene, dental hygiene, imunization  before and during of pregnancy, nutrition for female adolescent and pregnant women, taking early breastfeeding initiation,  and continue to give exclusive breastfeeding. Knowledge for 730 days after delivery involving knowledge about health card for toddlers, immunization for baby, growth and development of child 0 - 23 months, providing nutrition for 0-6 months and 7-24 months.The aim of this health services to improve knowledge of female adolescent about  the first 1000 days of human life. This study methode using health education to increase knowledge of adolescent. The results revealed that health education and demonstration can improve the knowledge of female adolescent about the first 1000 days of human life.
PERENCANAAN ARSITEKTUR SISTEM INFORMASI KEIMIGRASIAN PADA PLBN TERPADU DI NTT
Authors: Tjiptabudi Fransiskus Mario Hartono
Published: January 2020

Useful information system to support of business process an organization/company with no eception immigration authority. Business process that so far has been implemented have not use information technology maximally resulted in a fall in the passer the limits for the low service quality to the unfixed data storage and difficulty for finding data and produce reports. The purpose of the research are to design a cross platform information system architecture to support the business process carried out by the immigration authorities on three (3) Integrated Cross Border Posts (PLBN) under the control of the Class II Immigration Office of Atambua, East Nusa Tenggara. For the purposes of the architecture planning was using the framework of TOGAF ADM based on mapped problems, while the design of the information system is based on the PIECES framework. Information systems that proposed aims to solve the problems faced by and to support policy and the government's national strategies in the management of the border region. It is expected that the design of cross platform information system applied to linking immigration offices, immigration officers in PLBN and the passer. The results of this research are expected to be implemented in support of the business process on the immigration authorities with linking immigration offices, immigration officers in PLBN and the passer and also to improve the services of the immigration officer.
РУЧНА ОБРОБКА МЕДИЧНИХ ЗОБРАЖЕНЬ ЛІКАРЕМ-ДІАГНОСТОМ У СИСТЕМІ РОЗПІЗНАВАННЯ ТОМОГРАФІЧНИХ І РЕНТГЕНІВСЬКИХ ЗНІМКІВ ДЛЯ ПОШУКУ І ЛОКАЛІЗАЦІЇ ПАТОЛОГІЙ
Authors: А.І. Поляченко
Published: January 2020

У статті запропоновано та побудовано систему розпізнавання томографічних і рентгенівських знімків для пошуку і локалізації патологій. У даній статті необхідно розробити систему розпізнавання томографічних і рентгенівських знімків для пошуку і локалізації патологій та розглянути принципи ручної обробки медичних зображень лікарем-діагностом.
Для пошуку і локалізації аномалій на томографічних і рентгенівських знімках пропонується система, яка буде складатися з наступних блоків :  блок введення інформації про пацієнта; блок обробки медичних зображень, що включає: згорткову нейронну мережу (ЗНМ) для класифікації томографічних і рентгенівських знімків; ЗНМ для визначення залежностей значень просторового фактора  від стандартизованих -значень і з наступним розрахунком коефіцієнту загальної просторової автокореляції; ЗНМ для сегментації томографічних і рентгенівських знімків; підсистему ручної обробки медичних зображень, що представлена лікарем-діагностом;блок для встановлення висновку, що включає нейронну мережу (НМ), призначену для порівняння отриманих результатів; блок для класифікації виявлених патологій, що включає НМ; базу даних, як вже існуючих знімків, так і нових, у т.ч. з результатом оброблення;  блок підготовки звіту.
АНАЛІЗ ЯКОСТІ КОМПЛЕКСНИХ СУЛЬФОЦЕМЕНТОВАНИХ ПОКРИТТІВ, ОТРИМАНИХ МЕТОДОМ ЕЛЕКТРОІСКРОВОГО ЛЕГУВАННЯ
Authors: О.П. Гапонова
Published: January 2020

Проведений аналіз якості поверхневих шарів після сульфоцементації методом електроіскрового легування. Металографічні дослідження показали, що характерний для електроіскрових покриттів білий шар не виражений. Поверхневий шар складається з дифузійної зони, товщина якої збільшується зі зростанням енергії розряду, і основного металу. Дюрометричні дослідження сульфоцементованих покриттів свідчать про те, що в поверхневому шарі утворюються дві зони: зона зниженої мікротвердості та зміцнений шар. За даними мікрорентгеноспектрального аналізу, приповерхневий шар насичений сіркою. Сірка накопичується в поверхні металу на глибині до 30 мкм, її концентрація на цій відстані становить близько 0,4%. Зі збільшенням енергії розряду твердість, глибина шару зниженої мікротвердості і зміцненого шару, а також шорсткість поверхні збільшуються.
ЕКСПЕРИМЕНТАЛЬНА УСТАНОВКА ТА МЕТОДИКА ПРОВЕДЕННЯ ДОСЛІДЖЕНЬ КАНАТНОГО МЕХАНІЗМУ ДЛЯ ЗАВАНТАЖЕННЯ МАЛИХ СКЛАДСЬКИХ ПРИМІЩЕНЬ ЯБЛУКАМИ У ТАРІ
Authors: Р.Б. Гевко  , Ю.С. Никеруй
Published: January 2020

На основі розробленого комплексу запатентованих технічних рішень запропонована експериментальна установка канатного механізму для завантаження малих складських приміщень яблуками у тарі. Наведена методика проведення експериментальних досліджень для забезпечення ефективного виконання технологічного процесу при мінімальних травмуваннях яблук при їх транспортуванні для тривалого їх зберігання.
QUAL É O TAMANHO DO UNIVERSO? UMA PROPOSTA DE SEQUÊNCIA DE ENSINO INVESTIGATIVO SOBRE OS MÉTODOS DE ERATÓSTENES E ARISTARCO PARA MEDIR OS TAMANHOS DA TERRA E DA LUA
Authors: Ferreira Carlos Augusto , Bisch Sérgio Mascarello
Published: January 2020

O trabalho apresenta uma proposta de sequência de ensino investigativo para a Educação Básica sobre a determinação dos tamanhos da Terra e da Lua, seguindo os passos de Eratóstenes e Aristarco de Samos, numa abordagem que busca explorar os aspectos históricos e interdisciplinares envolvidos no desenvolvimento do tema. São indicadas questões e problemas abertosa serem apresentados aos estudantes e sugeridas sequências de atividades a serem realizadas com o intuito de levantamento de hipóteses e resolução, destacando a importância da observação atenta de fenômenos naturais comuns, como as sombras dos objetos e os eclipses lunares, associada à aplicação de princípios geométricos e físicos simples e uma atitude investigativa que leva à obtenção de resultados notáveis, como as dimensões da Terra e da Lua. A proposta representa um primeiro passo no desenvolvimento de um projeto de ensino mais amplo sobre o tema das dimensões do universo, que objetiva promover uma conscientização dos estudantes com relação ao Universo e à nossa posição dentro dele.
O ENSINO DE ASTRONOMIA E AS POSSIVEIS RELAÇÕES COM O PROCESSO DE ALFABETIZAÇÃO CIENTÍFICA
Authors: Rodrigues Fábio Matos , Briccia Viviane
Published: January 2020

Apresentamos nesse artigo uma discussão teórica sobre as possíveis relações entre o ensino de temas Astronômicos e os eixos estruturantes da Alfabetização Científica (SASSERON, 2015). Nesse estudo discute-se como características da Astronomia, aliadas ao ensino por investigação, tornam-se fortes aliadas ao processo de Alfabetização Cientifica, por possuir temas e atributos que podem tornar os alunos mais participativos no espaço educacional. Por meio de discussões que envolvem percepções e aplicações no dia a dia, o céu pode ser considerado como um elemento motivador, podendo modificar o espaço de aprendizagem da sala de aula, diminuir a distância entre discussões científicas e o cotidiano do aluno e também uma aproximação entre a teoria e a prática. Nesse sentido, apresentamos como a inserção de temas de Astronomia pode potencializar a leitura crítica do mundo para os estudantes, tornando-os mais autônomos e próximos do conhecimento científico em suas contextualizações, constituindo-se num forte aliado no processo de Alfabetização Científica.
PANORAMA DE PESQUISAS EM ENSINO DE ASTRONOMIA NOS ANOS INICIAIS: UM OLHAR PARA TESES E DISSERTAÇÕES
Authors: Pacheco Mayara Hilgert , Zanella Marli Schmitt
Published: January 2020

O objetivo deste trabalho foi identificar o que revelam as pesquisas produzidas entre 2008 e 2018 sobre ensino de astronomia nos anos iniciais do Ensino Fundamental a partir de uma revisão bibliográfica na Biblioteca Digital Brasileira de Teses e Dissertações, no Banco de Teses da Capes e Banco de Teses e Dissertações sobre Educação em Astronomia, utilizando as palavras “ensino de astronomia”. Foram identificados e analisados vinte e três pesquisas. Os resultados indicam que o ensino de Astronomia nos anos iniciais do Ensino Fundamental é uma área pouco explorada e revelam que: (1) há necessidade de repensar a formação inicial dos professores, visto que, durante a graduação muitos não tem contato com conteúdos de Astronomia; (2) os cursos de formação continuada podem suprir dificuldades do conhecimento e metodológicas do professor e (3) as pesquisas acadêmicas devem chegar até o professor dos anos iniciais para que estes possam participar de discussões acadêmicas sobre o tema.
Silk Fibroin Films Decorated with Magnetic Nanoparticles for Wound Healling Applications
Authors: Bunea Mihaela Cristina , Vasile Eugenia , Galateanu Bianca , Hudita Ariana , Serban Mirela , Zaharia Catalin
Published: January 2020

The paper is focused on designing a novel silk fibroin-magnetite biomaterial scaffold for wounds healing in terms of: synthesis, physico-chemical and morphological characterization and in vitro biological behaviour assessment. Magnetic scaffolds were prepared from silk fibroin solutions and magnetic nanoparticles with various concentrations by solvent casting technique. Specimens were investigated by FTIR-ATR spectroscopy and XRD measurements. Morphological investigation including internal structure was employed by AFM and TEM/HRTEM analyses. Biological assay was performed on human adipose derived stem cells isolated from subcutaneous adipose tissue. Results suggested that all the tested magnetic silk-magnetite scaffolds display a good biocompatibility in vitro on hASCs and could be promising candidates for further wound dressing testing.
Managing and Analyzing the Constructive and Functional Parameters on Fiberglass Custom Sensor Design for an Aerodynamic Balance
Authors: Pahonie Radu Calin , Stefan Amado , Costuleanu Carmen Luiza , Boldureanu Daniel , Andruseac Gabriela Gladiola
Published: January 2020

An external three component strain gauge balance, designed, analyzed and manufactured in the Military Technical Academy is presented. The balance is a multi-piece type and employs the use of six custom-made load cells (sensors) to transfer the aerodynamic forces and moments from the wing to the computer software environment for data processing and analysis. The relations between the loads acting on the wing model and the measured forces are also underlined. The placement of the strain gauge on the composite laminate is an important issue for increased sensor precision; therefore, it is given a thorough analysis. The positioning of the force vector and its influence on the strain distribution over the lift sensor is also numerically and experimentally analyzed.
Fused Deposition Modeling Technology to Redesign a Nylon Component
Authors: Pascu Nicoleta Elisabeta , Dobrescu Tiberiu , Popescu Adrian , Adir Victor Gabriel
Published: January 2020

3D printing by means of the Fused Deposition Modeling technology allows to obtain accurately and with very good results, plastic parts with various, simple or complex typo-dimensions and forms. The part in this article is from the field of road vehicles, it is called fixing clamp and it is of average complexity of the hole strip type with two protuberances necessary to ensure the purpose for which they provided. The necessity of making the part through addition appeared because it is not the market and because it was not provided by the supplier [1]. The constructive solution offered by the producer is a very good and necessary one, in the same time for the user in the equipment in which it is included (fig. 10). The constructive solution proposed in this article resulted from tests on some parts of Acrylonitrile-Butadiene-Styrene and Nylon and the results were conclusive for choosing and adopting the Nylon variant.
Biochemical Characteristics of Mini-implants Sterilised by Different Chemical and Physical Procedures
Authors: Pop Silvia Izabella , Bratu Dana Cristina , Chiorean Radu , Balan Raluca Adriana , Bud Anamaria , Petrescu Horatiu Pompiliu , Simon Catalin Petru , Dudescu Mircea
Published: January 2020

One hundred micro-implants from two different manufacturers were used in the study. From each manufacturer (Link from MISTM and Yesanchor from OrlusTM) the implants were divided in 5 groups: G0 (n=10) new, unused, G1 (n=10) mini-implants inserted in pig bone and removed, ultrasonically cleaned, followed by autoclave sterilization, G2 (n=10) same insertion protocol of group 2 followed by chemical cleaning with phosphoric gel and autoclave strerilization, G3 (n=10) same insertion protocol of group 1 followed by sandblasting and autoclave sterilization, G4 (n=10) same insertion protocol of group 2 followed by cleaning with distilled water and autoclave sterilization. Maximum insertion torque was recorded and subjected to statistical testing. Our results showed significant differences of the maximum insertion torques between groups of Link mini-implant (p=0.006), and no statistical differences of the maximum insertion torques of the Yesanchor implants (p=0.33). Significant differences (p[0.001) were also recorded between the groups of the two types of minii-mplants when compared. Our findings showed that brand-specific differences in maximum insertion torque exist between the two types of mini-implants.
Similar Short Term Outcomes with Press-fit Bipolar Hemiarthroplasty and Cemented Total Hip Replacements in Femoral Neck Fractures
Authors: Vermesan Dinu , Prejbeanu Radu , Haragus Horia , Niculescu Marius
Published: January 2020

There is limited data of short-term outcomes comparing press-fit bipolar and cemented total hip replacements in patients with femoral neck fractures. We therefore aimed to compare the perioperative incidents and immediate outcomes between press-fit stem bipolar head hemiarthroplasty and cemented total hip replacement in elderly patients with displaced femoral neck fractures. We reviewed prospectively collected data from 115 consecutive patients over 12 months. There were 21 cemented total hip replacements and 33 bipolar head press-fit stem hemiarthroplasties, with a male to female ratio of 1:1.84 and an average follow-up of 9.9 months (range 3-15). There were no differences between the two groups with respect to age (mean 77.4 years old), cortical index (0.77/ 0.82, p=0.087), hospitalization (17.7/ 16.7 days, p=0.59), bleeding, blood transfusions (14.3/ 18.2%, p=1.00) and Barthel index preoperatively, at discharge and 3 months (5.67/ 5.48, p=0.62; 10.57/ 10.47, p=0.89; 13.81/ 13.28, p=0.47). For all 54 patients the hemoglobin dropped from 13 to 11.2 g/dL after surgery without difference between implants. The mean duration of surgery was 21minutes (p[0.01) shorter for the press-fit hemiarthroplasty group compared to cemented total hip replacements. Our findings show comparable blood loss and functional outcomes with press-fit bipolar hemiarthroplasty and cemented total hip replacements for treating displaced femoral neck fractures in the elderly. Both were safe and allowed early recovery, with the only significant difference being the longer duration of surgery for the total arthroplasty.
Functionalization of Porous Clay Heterostructures with Silane Coupling Agents
Authors: Mihai (Voicu) Anda Ionelia , Garea Sorina Alexandra , Vasile Eugeniu , Nistor Cristina Lavinia , Iovu Horia
Published: January 2020

The goal of this paper was to study the modification of porous clay heterostructures (PCHs) with various silane coupling agents. Two commercial coupling agents (3-aminopropyl-triethoxysilane (APTES) and 3-glycidoxypropyl-trimethoxysilane (GPTMS)) with different functional groups (amine and epoxy groups) were used as modifying agents for the PCHs functionalization. The functionalization of PCH with APTES and GPTMS was evaluated by Fourier transform infrared (FTIR) spectrometry, thermogravimetric analysis (TGA), X-Ray Diffractions (XRD) and BET Analysis. FTIR spectra of modified PCHs confirmed the presence of characteristic peaks of silane coupling agents. TGA results highlighted an increase of weight loss for the modified PCHs that was assigned to the degradation of silane coupling agents (APTES and GPTMS) attached to the PCHs. The XRD results showed that the structure of modified PCHs was influenced by the type of the silane coupling agent. The functionalization of PCHs with silane coupling agents was also confirmed by BET analysis. Textural parameters (specific surface area (SBET), total pore volume (Vt )) suggested that the modified PCHs exhibit lower values of SBET and a significant decrease of total pore volume than unmodified PCHs.
Formulation and Characterization of Antibacterial Hydrogels Based on Polyurethane Microstructures and 1,2,4-Triazole Derivatives
Authors: Moleriu Lavinia , Duse Adina Octavia , Borcan Florin , Soica Codruta , Kurunczi Ludovic , Nicolov Mirela , Mioc Marius
Published: January 2020

Antibacterial gels offer an efficient hygiene in the absence of soap and water. The most part of these products are based on mixtures of different antibacterial and fungicide substances dissolved in an alcohol. Unfortunately, all cosmetic products containing alcohols wash the sebum and dry the skin. In the present study, alcohol-free antibacterial hydrogels were obtained through the synthesis of polyurethane (PU) microstructures with an increased amount of surfactant; 5-mercapto-1,2,4-triazole derivatives were used as active compounds inside the PU microstructures as antibacterial agents. There were studied: the pH of samples, the size and stability of PU microstructures, the skin irritation, sebum level and the hydration of stratum corneum using the mouse model and their efficiency against Escherichia coli. The results indicate that were obtained hydrogels with a slightly acid pH, PU microstructures with sizes between 185 and 265 nm and with a medium stability. It was found that these new antibacterial hydrogels do not produce an important modification of skin parameters (erythema, melanin, sebum and hydration of stratum corneum) and are efficient against E. coli.
Iono-molecular Separation with Composite Membranes IV. Mono-nitrophenol s pervaporation through polysulfone composite membranes
Authors: Abdalraheem Al Ani Hussam Nadum , Cimbru Anca Maria , Din Ion Spiridon , Tanczos Szidonia Katalin , Nafliu Ion Marius , Cuciureanu Adriana
Published: January 2020

In this paper, were study the pervaporation of mono-nitrophenols in a laboratory installation of the Membrane, Materials, and Membrane Processes Group of the Polytechnic University of Bucharest, from aqueous synthetic solutions, to composite membranes with polysulfone matrix (PSf) and nanometric inclusions: Polyaniline (PANI), carbon nanotubes (CNT), magnetic nanoparticles (MNP) and sulfonated polyetheretherketone (PEEK-S). Tests carried out over 144 h at a pressure of 100 mm Hg or 5 L / min air flow at 25oC and pH 7 of the feed solution show that vacuum pervaporation is better than vacuum. The more advanced composite membranes are those with sulfonated polyether-ether cellulose (PSf-PEEK-S) and polyaniline (PSf-PANI) ionizers. The results of airborne pervaporation show that composite membranes (PSf-PEEK-S and PSf-PANI) present a marked difference in flux for the mono-mono-nitrophenol isomers, which could also be found in a technically exploitable selectivity. Thus, in the case of the PSf-PEEK-S composite membrane, the mono-nitro-phenol streams decrease in the order: m-C6H5NO3] o-C6H5NO3] p-C6H5NO3, while for the PSf-PANI composite membrane the order is o-C6H5NO3] m-C6H5NO3] p-C6H5NO3. At the same time, it is noted that the PSf-PEEK-S composite membrane performance is superior during operation, but shows the opposite of the more pronounced drop.
Collagen Films Obtained from Collagen Solutions Characterized by Rheology
Authors: Popa Simona , Boran Sorina , Simulescu Vasile
Published: January 2020

Collagen is an important natural biopolymer, found in mammal s body. It is the main structural protein in the extracellular space in the various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals. Its importance increased in last decades. Collagen has many applications in medicine and cosmetics. The work presented in this paper shows one method to obtain collagen films from collagen solutions. These collagen solutions were characterized by rheological measurements. The preparation of the collagen films was performed in the presence of calcium and silicium salts, using glycerin as plasticizer. The collagen was first solubilized and reconstituted, in order to maintain its initial properties.
Effect of Finishing Techniques on the Junction Between the Composite Restoration and the Dental Enamel
Authors: Iovan Gianina , Stoleriu Simona , Pancu Galina , Nica Irina , Sandu Andrei Victor , Andrian Sorin , Tanculescu Oana
Published: January 2020

The aim of this in vitro study was to to evaluate the impact of finishing procedures on the enamel adjacent to composite restorations and to assess if the resistance of the enamel-resin junction to leakage is affected by the use of these instruments. The surfaces of enamel at the joint with composite were observed by scanning electron microscopy, then the microleakages at the enamel margin was assessed using an optical microscope. Finishing with extra-/ ultra-fine carbide burs and extra-fine diamond burs produced a superficial abrasion to the adjacent enamel and did not seem to have a significant influence on the sealing ability of composite resin.
Study Concerning the Influence of the Grinding Percentage on Some Electrical Properties of PA 6.6, POM and ABS by Methods for Determining Relative Permittivity and the Dielectric Dissipation Factor
Authors: Novac Ovidiu Constantin , Maries Gheorghe Radu Emil , Chira Dan , Novac Mihaela
Published: January 2020

This paper presents the influence of the grinding percentage on some electrical properties, when the process of injection is used in the production of technical commodities, made of polyamide 6.6 (PA 6.6), polyoxymethylene (POM) and acrylonitrile butadiene styrene (ABS), for different industries. The specimens produced had the following compositions: new material 100%, new material 80% + grinding 20%, new material 60% + grinding 40%, new material 40% + grinding 60%, new material 20% + grinding 80% and 100% grinding. The measurement of the electrical properties was carried out using the methods for the determination of relative permittivity and of the dielectric dissipation factor, with the method of zero by Schering bridge. It was found that increasing the percentage of grinding in samples, from 0% to 100%, determined a slight increase in the values of relative permittivity at all three polymers tested and the increase of measurement frequencies for acrylonitrile butadiene styrene and polyoxymethylene led to insignificant changes in the values of relative permittivity, while in the case of polyamide, increasing the measurement frequency led to a slight decrease in the values of relative permittivity. It was also found that increasing the proportion of grinding in the specimens, from 0% to 100%, determined a slight increase in the values of the dielectric dissipation factor in the case of polyamide and polyoxymethylene, while in the case of acrylonitrile butadiene styrene increasing the percentage of grinding in the samples resulted in insignificant changes. The increase in the measurement frequencies for the three tested polymers resulted in a decrease in the values of the dielectric dissipation factor.
Using Polypropylene for Bronchial Stump Closure After Pulmonary Resections
Authors: Suciu Bogdan Andrei , Halmaciu Ioana , Bud Vasile , Copotoiu Constantin , Fodor Decebal Romulus Petru , Trambitas Cristian , Vunvulea Vlad , Molnar Calin , Brinzaniuc Klara
Published: January 2020

The bronchial stump fistula shown by patients undergoing adjusted pulmonary resections is an extremely severe condition affecting the prognosis of this patients. Within our study, we have used an innovative technique of closing the bronchial stump for 38 patients undergoing adjusted pulmonary resections. The suture of the bronchial stump was made through an innovative method, by practicing the suture with isolated 2.0 Prolene wires armed with patches of Polypropylene. The incidence of the bronchial stump fistula for the observed lot was of 5.26% (2 cases), smaller than the one reported in the specialty literature. In this respect, we consider that the use of Polypropylene in the techniques of closing the bronchial blunt can be beneficial.
Parametric Study of Experimental and Numerical Simulation of Sandwich Composite Structures Flexural Behaviour
Authors: Beznea Elena Felicia , Chirica Ionel , Baroiu Nicusor , Teodor Virgil
Published: January 2020

Sandwich panels with composite/steel skin sheets and foam core are very often used as lightweight structures in automotive, maritime and aerospace applications due to their performances like high bending stiffness and strength and also lightweight. As an alternative to classical structural reinforced panels, the sandwich structures are justifying their use in various industrial fields, making these structures less complex, by eliminating the need for secondary stiffening. In the paper are presented three models of sandwich, steel-foam-steel, composite-foam-composite or steel-foam-composite structures, of different thicknesses, with functional use in various fields depending on necessities. The mechanical characteristics of the materials used in their manufacture have been determined. The panels have been subjected to various load cases in order to determine an optimal combination of weight and strength. At the same time, the numerical models used in the finite element analysis of the sandwich structures with specific elements for layered composites or sandwich (SHELL 4L and SOLID L) are presented.
Impact Testing on Composite Panels of Fiberglass, Carbon and Kevlar-Carbon A comparison and validation study
Authors: Croitoru Emilian Ionut , Oancea Gheorghe , Constantin Nicolae
Published: January 2020

A validation study between finite element analysis and experimental testing considering an impact loading of Fiberglass, Carbon and Kevlar-Carbon composite panels of 150 x 100 mm2 was conducted by the authors. Using the design of experiments method and the Design Expert software tool, the data obtained in FEA environment is validated, through means of statistical distributions, by the experimental tests results.
Trinia Reinforced Polymer as Core for Implants Superstructure
Authors: Biris Carmen , Bechir Edwin Sever , Bechir Anamaria , Mola Farah Curt , Caraiane Aureliana , Badiu Adrian Viorel , Gioga Cherana
Published: January 2020

The intraosseous implants are the most used dental implants. The development of new classes of dental biomaterials determined the apparition of Trinia, a Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) reinforced polymer, used for core in non-metallic prosthetic restorations, including implants superstructure. The aim of the study was to present the obtained results in the use of Trinia polymer as non-metallic core on the abutments of Bicon implants. 35 patients were selected, 19 females and 16 males, aged between 31 and 60 years. After 18 months of results monitoring, we ascertained that Trinia reinforced polymer had a very good behavior in the oral cavity, and the patients did not complain about inconveniences due to the oral rehabilitation with this biopolymer.
Styrene-diene Block-copolymers Reinforced with Polystyrene
Authors: Ghioca Paul , Grigorescu Ramona Marina , Iancu Lorena , Spurcaciu Bogdan , Nicolae Cristian Andi , Gabor Augusta Raluca
Published: January 2020

The paper presents the polystyrene reinforcing effect of some styrene-diene block-copolymers on the physical-mechanical characteristics and thermal degradation stability of the associated composites.
Influence of Polymer Concentration on Membrane Performance in Wastewater Treatment
Authors: Tiron Laurentia Geanina , Pintilie Stefan Catalin , Lazar Andreea Liliana , Vlad Maria , Balta Stefan , Bodor Marius
Published: January 2020

Water is an important element of life, while every industry in its processes uses an important amount of water. Following processes, the water is contaminated and requires water treatment technologies. Unconventional methods to wastewater treatment, in the last years, use membrane technology as one of the most reliable processes for contaminants removal. In this article, the influence of the different concentrations of polysulfone (PSf) on the polymeric membranes properties was studied. These membranes were obtained through phase inversion method and with different polymer concentrations: 23, 25, 27 and 30 wt.%. The performance of the membranes was studied by pure water flux, permeability and retention. It has been observed that by increasing the polymer concentration, the pure water flux and the permeability will decrease. Retention was determined using methylene blue, which is one of the most utilized dye from industry and it could be observed that by increasing the polymer concentration the retention degree of the pollutant also increases. In order to explain the evolution of membrane permeability at different polymer concentrations, surface hydrophilicity by contact angle method and cross-section SEM imaging were used.
Formulation of Polymeric Multicomponent Systems Containing Cardiovascular APIs
Authors: Sha�at Fawzia , Pavaloiu Ramona Daniela , Salceanu Daniela Crina , Hlevca Cristina , Nechifor Gheorghe
Published: January 2020

The main aim of this study was to prepare and characterize polymeric nanoparticles containing two cardiovascular active pharmaceutical ingredients: valsartan (VAL) and amlodipine besylate (AML). Six formulations were evaluated with different ratios of AML:VAL:PLGA (1:16:17, 1:16:34, and 1:16:51) and different stirring speed (1200 and 2400 rpm). Encapsulation efficiency (EE, %) and particle size analyses were performed to characterize and optimize the formulation. All loaded nanoparticles showed a high EE (%), nano-size, negative x-potential and a high homogeneity.
Evaluation of Pre-heating Effects on Marginal Adaptation of Resin-based Materials
Authors: Taraboanta Ionut , Stoleriu Simona , Iovan Gianina , Moldovanu Antonia , Georgescu Andrei , Negraia Magdalena Rusu , Andrian Sorin
Published: January 2020

The aim of the study was to compare the marginal adaptation of three different resin-based materials used for direct restoration: hybrid composite resin (Gaenial Posterio, GC Corporation), a compomer (Dyract eXtra, Dentsply Sirona), and a giomer (Beautifil II, Shofu Dental) applied at room temperature or after preheated at preheating 50 and 60oC. Class II cavities were prepared on proximal surfaces of extracted teeth and randomly divided in 3 groups according to the material used for restoration. In each group five cavities were restored using the materials at room temperature (subgroup 1), five cavities were restored using preheated materials at 50şC (subgroup 2), and five cavities were restored using preheated materials at 60şC (subgroup 3). The teeth were stored in distilled water for 14 days and then were immersed in 2% methylene blue buffered dye solution (pH = 7) for 4 hours. The teeth were transversally cut and the sections were examined using optical microscope (Carl-Zeiss AXIO Imager A1m) at 50x magnification and the dye penetration was evaluated according to 4 scores. Decreased microleakage and fewer gap formation were recorded for all filling materials after they have been heated at 50 or 60oC. Pre-warming of resin-based materials improves the adaptation of these materials to tooth structures.
The Antioxidant Effect of PLGA Nanoparticles Encapsulated with Lutein in Rats Treated with Hypercaloric Diet
Authors: Radulescu Catalina , Miricescu Daniela , Calenic Bogdan , Radulescu Radu , Stanescu Iulia , Calenic Anca , Totan Alexandra , Virgolici Bogdana , Balan Daniela , Greabu Maria
Published: January 2020

Poly lactic-co-glycolic acid (PLGA) is a biodegradable polymer that has been the focus of intense research due to its potential applications in medical research. Its uses in nanotechnology are underlined by its capability of targeting various cells and delivering active compounds to different human tissues. To date, PLGA nanoparticles are employed in areas such as vaccination therapy, diagnostic imaging procedure and various applications in various anticancer therapies. The aim of the present study is to measure and evaluate different correlations between oxidative stress parameters in spleen and liver following administration of nanoparticles encapsulated with lutein in an animal model. Our results show that acute oral administration of PLGA NPs induces a change in the oxidative stress status in both liver and spleen of rats, but does not induce oxidative stress damage to cell structures such as lipids or proteins.
Evaluation of AML-VAL Nanoparticles as Combined Therapy in Cardiovascular Disease
Authors: Shaat Fawzia , Pavaloiu Ramona Daniela , Salceanu Daniela Crina , Hlevca Cristina , Nechifor Gheorghe
Published: January 2020

The main aim of this study was to investigate a mixture of two poorly water-soluble active pharmaceutical ingredients (APIs): an angiotensin II receptor antagonist (valsartan) and a calcium channel blocker (amlodipine besylate), chosen in a fixed-dose, in order to obtain new polymeric nanoparticles (NPs) for cardiovascular diseases treatment. NPs were prepared via nanoprecipitation method using poly (D,L-lactide-co-glycolide) (PLGA) as matrix and Pluronic F127 as stabilizer. Three formulations were investigated with different ratios of AML:VAL:PLGA (1:16:5, 1:16:7.5 and 1:16:10). Particle size, polydispersity index and zeta-potential analyses were performed to characterize and optimize the formulation. The in vitro drug release study was determined by using a dialysis membrane method under sink conditions. All NPs loaded with both APIs showed nano-size, negative potential, a high homogeneity and a slow drugs release in physiological environment.
PP/EPDM Polymeric Compounds Dynamically Cured Compatibilized and Reinforced with Nanoclay
Authors: (Vilsan) Nituica Mihaela , Meghea Aurelia , Gurau Dana , Stelescu Maria Daniela
Published: January 2020

This paper presents the development of dynamically cured polymer composites and nanocomposites based on plastomer - PP (polypropylene) and EPDM elastomer (ethylene-propylene-diene-terpolymer) compatibilized and reinforced with nanometric particles-MMT (montmorillonite, chemically modified layered clay) in two stages, by extrusion-granulation and mixing. Nanoparticles increase the thermal resistance of dynamically cured polymer nanocomposites. By means of compatibilization and dynamic curing, elastomer particles - EPDM are more easily dispersed in the mixture. The materials obtained were tested physicomechanically (Melt Flow Index) and morpho-structurally (FT-IR and DSC).
Comparative Characterization of Birch Bark Extracts Encapsulated Inside Polyurethane Microstructures
Authors: Borcan Florin , Preda Marius , Borcan Livia Cristina , Pinzaru Iulia , Florescu Sorin , Sisu Eugen , Poenaru Marioara
Published: January 2020

The phytotherapy is based on the consume of fruits, vegetables and medicinal plants; they contain mixtures of bioactive chemical substances (carotenoids, phenolic acids, flavonoids, coumarins, tannins, organosulfur compounds) with synergic effects on the treatment of diseases. Nano- and micro-carriers are very useful drug delivery systems which can improve the transmembrane transfer of natural extracts. In the present study, betulin and two birch bark extracts were encapsulated inside polyurethane microstructures. Structures� size, homogeneity and surface charge were studied using a Zetasizer, while DSC analysis was involved to assay structures� thermal behavior. Irritation effects were monitored by non-invasive techniques on human skin. The results indicate the obtaining of structures with size around 200-250 nm, with a positive surface charge and a very good thermal stability. The non-irritation potential recommends these structures as a safe delivery system used for natural extracts.
Adhesion of Scaffolds with Implants to the Mandibular Bone with a Defect A finite element analysis
Authors: Gabor Alin , Zaharia Cristian , Todericiu Vlad , Szuhanek Camelia , Cojocariu Andreea Codruta , Duma Virgil Florin , Sticlaru Carmen , Negrutiu Meda Lavinia , Antoniac Iulian Vasile , Sinescu Cosmin
Published: January 2020

In most patients with complete or partially stretched edentations requiring a dental implant, there is insufficient alveolar bone for a proper morpho- functional prosthetic restoration. Therefore, in many cases a bone addition is required for the implant treatment. The aim of this study is to evaluate ex-vivo, with numerical simulations, a large mandibular bone defect that is restored by using a three-dimensional (3D) printed ceramic scaffold. In order to obtain a proper morphological and functional prosthetic restoration, a thick mandibular bone is utilized for the implant treatment. The polymeric scaffold is attached to the mandibular bone with one, two, or three implants. By scanning the mandible with MicroScribe 3G and then employing a Finite Element Analysis (FEA) with Pro/Engineer and ANSYS 15, the study performs a numerical simulation and thus assesses the effects of the force applied to the scaffold.
Mechanical Properties of Fly Ash Polymer Concrete with Different Fibers
Authors: Barbuta Marinela , Timu Alexandru , Bejan Liliana , Bucur Roxana Dana
Published: January 2020

The experimental results obtained by studying the influence of different types of fibers on the mechanical properties of fly ash polymer concrete are presented in the paper. The general demand of using wastes found applicability in building material industry because some of them are beneficial in improving concrete properties. The waste additions type fly ash and fibers were incorporated in polymer concrete. The study focused on fibers type glass, polyester, metallic and cellulose. The mechanical properties such as compressive strength, flexural strength and split tensile strength were investigated having in view the type, dosage and length of fibers. The results show that fibers improved mechanical properties in comparison with that of polymer concrete without fibers, the test results being differently influenced by the factors which were considered.