bluuebunny/crossref_metadata_2025_split huggingface dataset:
Helical drilling of carbon fiber reinforced polymer by a femtosecond laser
Authors: Wang Xuehui , Chen Hang , Li Zhengyan , Qin Yingxiong , Zhu Xiao , Tang Xiahui , Wen Bin 
Published: December 2021

Carbon fiber reinforced polymer (CFRP) has been widely used in the aerospace industry and other fields, but its processing is still subject to many restrictions. A femtosecond laser helical drilling device is proposed. It can realize beam deflection and translation through a scanning galvanometer and a pair of lenses, respectively, and finally obtain the effect of beam oblique focusing. With the combination of a spiral scanning path and focus feed, the non-taper and high-quality drilling of materials can be realized. CFRP materials were processed through this method, and the influences of process parameters on the heat affected zone and machining taper were studied. The distribution and influence degree of the heat affected zone and the formation mechanism of the machining taper were analyzed. Finally, a high-quality straight hole processing effect of CFRP with up to a 9.7: 1 aspect ratio, less than 15 µm heat affected zone outside the hole, and no delamination in the hole was realized. This new drilling method is expected to further expand CFRP applications.
Prevalence of hepatitis B and C among female sex workers in Togo, West Africa
Authors: Bitty-Anderson Alexandra M. , Ferré Valentine , Gbeasor-Komlanvi Fifonsi A. , Tchankoni Martin Kouame , Sadio Arnold , Salou Mounerou , Descamps Diane , Dagnra Claver A. , Charpentier Charlotte , Ekouevi Didier K. , Coffie Patrick A. 
Published: December 2021

Background
Hepatitis B and C are endemic in sub-Saharan Africa, with prevalence among the highest in the World. However, several challenges impede the progression towards the elimination of viral hepatitis by 2030 as suggested by the World Health Organization Global health sector strategy on viral hepatitis, including the lack of knowledge on the scale of this epidemic in the region. The aim of this study was to estimate the prevalence of hepatitis B and C among female sex workers (FSW) in Togo.

Methods
This ancillary study from a national cross-sectional bio-behavioral study was conducted in 2017 using a respondent-driven sampling (RDS) method, in eight towns of Togo among FSW. Socio-demographic, behavioral and sexual characteristics were assessed using a standardized questionnaire. Blood samples were collected for HIV, hepatitis B and C serological testing. Data were analyzed using descriptive analysis and a logistic regression model.

Results
Out of the 1,036 FSW recruited for this study, biological analyses for viral hepatitis were completed for 769 of them. The median age was 26 years [IQR: 22–33] and 49.8% (n = 383) had attained secondary school. The prevalence of hepatitis B was 9.9% [95% CI: (7.9–12.2)] and the prevalence of hepatitis C was 5.3% [95% CI: (3.9–7.2)]. Higher hepatitis B and C prevalence was associated with recruitment out of Lomé (aOR: 6.63; 95%CI: 3.51–13.40, p <0.001 and OR: 2.82; 95% CI: [1.37–5.99]; p<0.001, respectively) and, for hepatitis B, with never using condoms for vaginal intercourse (OR: 3.14; 95%CI: [1.02–8.71]; p<0.05).

Conclusions
Results from this study reveals high prevalence of hepatitis B and C among FSW in Togo and an opportunity for advocacy toward the introduction of immunizations and treatment in this population.
Mother-to-child transmission of HIV infection and its associated factors in the district of Bilene, Gaza Province—Mozambique
Authors: Osório Dulce , Munyangaju Isabelle , Nacarapa Edy , Muhiwa Argentina , Nhangave Amancio Vicente , Ramos Jose Manuel 
Published: December 2021

Background
Mother-to-child transmission of HIV infection is a significant problem in Mozambique. This study aims to determine the risk factors associated with mother-to-child transmission of HIV in rural Mozambique.

Methods
Retrospective case-control study in a rural area of Bilene District, on the coast of southern Mozambique, performed from January 2017 to June 2018. The analysis considered the clinical data of HIV exposed children with definitive HIV positive results and their respective infected mothers (cases), and the data of HIV exposed children with definitive HIV negative results and their respective infected mothers (controls) registered in At Risk Child Clinics from 1st January 2017 to 30th June 2018 at the Macia and Praia de Bilene health facilities in Bilene district, Gaza province–Mozambique.

Results
Ninety pregnant women with HIV were involved in the study, including 30 who had transmitted the infection to their children and 60 who had not. Statistical analysis, adjusted for maternal age and gestational age at first antenatal care visit, showed that independent risk factors for transmission were gestational age at first visit (adjusted odds ratio [aOR] 1.19, 95% confidence interval [CI] 1.05–1.36), non-adherence to combination antiretroviral therapy (56.7% vs. 5%; aOR 14.12, 95% CI 3.15–63.41); a viral load of 1000 copies/mL or more (90% vs. 5%; aOR: 156, 95% CI 22.91–1,062) and female sex of the neonate (80% vs. 51.7%; aOR: 4.43, 95% CI 1.33–15.87).

Conclusion
A high viral load and non-adherence to antiretroviral therapy are important predictors of mother-to-child HIV transmission.
Avaliação da densidade radiográfica de defeito periodontal em suínos utilizando imagem digital
Authors: Giovanini Ellen Greves , Salzedas Leda Maria Pescinini , Sundefeld Maria Lúcia Marçal Mazza 
Published: December 2021

A imagem digital tem sido utilizada como um importante recurso diagnóstico na Odontologia. A dificuldade no diagnóstico dos defeitos de furca desperta particular interesse, visto que o tratamento está relacionado à extensão do defeito ósseo. Além da qualidade da imagem, a habilidade do observador é essencial para o diagnóstico. Recurso técnico como a densidade poderia auxiliar na análise comparativa das imagens do mesmo defeito, entre os períodos de observação. O objetivo deste estudo foi avaliar a densidade radiográfica como auxiliar na determinação da extensão de defeitos de furca. Foram criados 24 defeitos de furca em dente birradicular mandibular de suínos, com profundidade crescente, numa seqüência de remoção óssea simulando envolvimento de furca grau I, II e III; sendo obtidas imagens digitais a cada passo. Determinou-se a média de densidade dos defeitos (inicial, grau I, grau II, grau III), num total de 96 imagens. Com os valores obtidos foi realizada análise de variância e teste de Tukey para comparação entre os graus de envolvimento de furca. Houve diferença significativa (p<0,001) entre os defeitos: inicial e grau I, II e III; grau II e III. Não houve diferença significativa apenas entre os defeitos grau I e II (p>0,05). A média de densidade para os grupos foi: inicial - 126,98; grau I - 112,52; grau II - 106,22; grau III - 80,63. Concluiu-se que a densidade radiográfica pode auxiliar na quantificação de defeito de furca, constituindo recurso adicional à habilidade do observador.
Influence of additional polymerization in the microhardness of direct composite resins
Authors: Lombardo Geraldo Henrique L. , Carvalho Cristiane F. , Galhano Graziela , Souza Rodrigo Othávio A. , Júnior Lafayete N. , Pavanelli Carlos Augusto 
Published: December 2021

Objective: To evaluate different methods of additional polymerization in the Vickers’ microhardness of three composite resins. Material and Methods: With assistance of a metallic matrix (3 x 4mm), 30 specimens (sps) of each direct resin composite (drc) were prepared, entitled: Filtek Z250(3M ESPE, Saint Paul/MN-USA)(Gr1), W3D(Wilcos, Petrópolis/ RJ-Brazil)(Gr2), and EstheticX (Dentsply/York/PA-USA)(Gr3). All sps were photopolimerized, by the incremental technique, during 40 seconds (Gr1 - n=10: control). After that, 20 samples of each group were divided and half of the samples (n=10) were submitted to the additional polymerization during 15 minutes to 127ºC in autoclave (Gr2) and the other half in stove (Gr3). After all sps were stored in distilled water (37ºC/24 hours). The microhardness was accomplished in digital machine (Future-Tech, FM 700 Model), with 50kg of load. The data obtained (Kg/mm2) were analyzed utilizing the ANOVA Test (2 factors) and Tukey test (p<0.05). Results: The values of mean ± standar deviations obtained were: Gr1a(84,2±5,1), Gr1b (71,6±6,7), Gr1c (89,6±7,4), Gr2a (101,1±6,0), Gr2b (96,4±9,0), Gr2c (112,6±7,3), Gr3a (74,0±6,5), Gr3b (66,0±12,7) e Gr3c (81,7±6,5). The polymerization in stove produced a higher microhardness than the other kinds of polymerization (p<0.05) and the microhardness of the resins statistically differed among them (p<0.05). Conclusion: The additional polymerization of the Filtek Z250 in the stove produced microhardness statistically higher than the others.
The long-term effect of sparkling flavored water on human tooth enamel determined by gravimetric analysis: a preliminary evaluation
Authors: Marchan Shivaughn M , Bascombe Kelee , Hector Trevin , Smith William AJ , Ramnanansingh Terry G 
Published: December 2021

Objective: The aim of this study was to assess the in vitro effect of flavored waters on human tooth enamel using a gravimetric method. Lingual surfaces of lower molars were used to obtain enamel specimens. Material and Methods: Enamel (n=3) was washed and dried, immersed in 6 flavors of locally available of flavored sparkling water and assessed using gravimetric analysis, periodically for up to 9 days. Additionally, pH measurements of the flavored waters were recorded. Results: All the tested flavored waters showed pH values below that of critical pH. Paired t-tests demonstrated significant reductions in the mean group mass for all enamel specimens from as early as day 1 after immersion in flavored water, compared to baseline measurements. Further reductions in mean mass continued up to day 9 of immersion. Conclusion: Flavored waters are potentially erosive to human enamel specimens with the erosive effect being cumulative over time.KeywordspH; Enamel; dental erosion.
HUBUNGAN STUNTING DENGAN KETERLAMBATAN PERKEMBANGAN PADA ANAK USIA 6-24 BULAN
Authors: Wulandari Eka Cahyaningsih , Wijayanti Hartanti Sandi , Widyastuti Nurmasari , Panunggal Binar , Ayustaningwarno Fitriyono , Syauqy Ahmad 
Published: December 2021

Background: The prevalence of stunting in Semarang in 2017 reached 20.37% with the highest incidence in the working area of the Bandarharjo Public Health Center. Previous studies have shown children who are stunted up to 2 years old has lower intelligence score than children who are not stunting. However, there were not studies on the relationship of stunting whit development children under 2 years.Objectives: This study aimed to determine relationship between stunting and development of children 6-24 months in the working area ofBandarharjo Public Health Center.Methods: This was a cross sectional study on 54 subjects aged 6-24 month using consecutive sampling method. Height and body weight were measured to assess nutritional status. Degree of stunting was expressed by height for age z-score of (HAZ) and classified according to the WHO. Development status was measured with Denver II test. Nutrient intake was measured by a semi quantitative Food Frequency Questionnaire (FFQ) and entered into Nutrisurvey 2007. The data analyzed with chi-square test and Fisher Exact. Multivariate analysis was done by logistic regression.Results: As many as 31,5% children were stunting and 72,2% children classified into suspect category. Stunting children had 9.3 times the risk of developmental delays compared with children who are not stunting.Conclusion: There was significant relationship between stunting and development of children 6-24 months of age in the working area ofBandarharjo Public Health Center.
Influence of silver/silver chloride electroless plating on the Shore hardness of polyurethane substrates for dry EEG electrodes
Authors: Fauzhan Warsito Indhika , Machts René , Griebel Stefan , Fiedler Patrique , Haueisen Jens 
Published: December 2021

Abstract
Dry electrodes enable a shorter preparation time for infant EEG. Since infant skin is more sensitive than adult skin, soft electrodes are required to reduce the mechanical stress for this sensitive skin. Thus, soft electrodes are crucial for eventual repetitive and long-term use like in neonatal intensive care units. A biocompatible polyurethane (PU) can be produced in low hardness resulting in a soft and flexible electrode substrate. Silver/silver chloride (Ag/AgCl) electroless plating provides a conductive, electrochemically stable coating but the process may alter the mechanical properties of the electrode substrate. In this study, we assess the hardness of PU material before and after Ag/AgCl plating. The test sample design for Shore hardness measurement is based on ISO 7619-1:2010. Sample production consists of a 3D print master model, silicone molding, PU casting, and finally electroless plating. UPX 8400-1 (Sika AG, Switzerland) is used for the sample substrates. Test samples are produced with 7 different Shore hardness (range A40-A95) and 14 samples (each hardness: 1 uncoated and 1 coated). The hardness measurements are carried out with a lever-operated test stand Shore hardness tester model with a digital hardness tester (TI-AC with HDA 100-1, KERN &SOHN GmbH, Germany).. It is shown that there is a hardness increase (Shore A) due to Ag/AgCl coating with a grand average of 1.1±0.7 (p<0.05). The largest increase of 2.1±0.2 is seen on the initial lowest Shore hardness sample (Shore hardness: 43.4±0.1). The absolute increase of hardness due to the Ag/AgCl coating decreases with increasing substrate hardness. It is concluded that there is no strong hardness increase of PU substrates due to Ag/AgCl plating. Therefore, the material is suitable as a soft electrode for repetitive and long-term use in infant applications.
Microchip Transfer Process for Implantable Flexible Bioelectronic Devices
Authors: Martens Julien , Gueli Calogero , Eickenscheidt Max , Stieglitz Thomas 
Published: December 2021

Abstract
The demands on flexible implants for recording of neural signals and electrical stimulating have increased in recent years with regard to their functionality, miniaturization, and spatial resolution. These requirements can be met best by embedding powerful complementary metal oxide semiconductor (CMOS) microchips into thin biocompatible polymer substrates. So-called chip-in-foil systems thus combine mechanical properties of a polymer substrate and performance of CMOS technology. The development of a process for direct transfer of multiple CMOS microchips (edge length <400 μm) simultaneously into thin polyimide (PI) substrates is subject of this study. It allows the use of standard microelectromechanical systems (MEMS) processes for further levelled superficial layer build-up. This is achieved with the help of a silicon carrier wafer equipped with cavities for precise chip placement and a sacrificial layer to facilitate release of the chip-in-foil systems. In a post-processing step all silicon chips are thinned down to 100 μm. With this process a transfer yield of 100 % (n = 34) was achieved for the silicon chips on a die level. Chip rotational error on substrates was determined to be as low as 0.21° ± 0.10°. Die adhesion was examined by shear tests, resulting in shear strength of 58.1 MPa ± 13.7 MPa, which dropped to 15.2 MPa ± 10.5 MPa after accelerated ageing in 60 °C phosphate buffered saline solution (PBS) for 16 days (equivalent to 78 days at 37 °C). This study demonstrated a reliable microchip transfer process with low positioning error into flexible PI substrates with post-processing thinning of the dies. The use of a carrier silicon wafer allowed precise electrical interconnect fabrication with standard MEMS processing techniques and without handling of thin and fragile chips. These results are a prerequisite to meet needs of reliability and structural biocompatibility in implantable flexible bioelectronic devices.
Movement filtered heart rate variability (HRV) data from a chest-worn sensor
Authors: Hanshans Christian , Broell Lukas M. , Plischke Herbert , Offenbaecher Martin , Zauner Johannes , Faust Moritz M. R. , Maisch Bettina , Kohls Niko , Toussaint Loren , Hirsch Jameson , Siros Fuschia M. 
Published: December 2021

Abstract
Recording of heart rate variability (HRV) is a noninvasive and continuous measurement method that allows investigating the autonomic nervous system (ANS) and its reaction to environmental influences. For a precise measurement of HRV data, a carefully chosen study design and environment is required to minimize secondary influences. One major influence to be avoided is movement. However, in the daily routine and for some scientific questions, movement can often not be avoided. If so, a manual or automated method to differentiate between artifacts caused by body movement and the actual psychophysiological effect is needed to ensure the data quality. In this approach, a chest-worn sensor was developed, that measures the heart rate using a single lead ECG and filters the measured change of the HRV caused by movement. Data from an integrated accelerometer is used to detect upper body movements that affect the resting heart rate. The movementcorresponding time stamps are then used to filter the Interbeat Intervals (IBI) accordingly. Functionality and effectiveness of the sensor system have been tested against state-of-the art sports- or clinical devices in varying scenarios. As our test series showed, motion filtering has a decisive effect when motion occurs, two-thirds of all cases showed a significant effect of motion filtering, with small to medium effect sizes for the parameters SD2, SD2/SD1, and SDNN. Thereby, automatic filtering of motion artifacts can help to significantly reduce the need for costly post-processing of distorted data sets. The results show a better data quality of HRV measurement, a method that is commonly used for the investigation of physiological processes in the field of chronic pain, psychology, psychiatry, or sports medicine.
A neuromonitoring framework supporting the intraoperative placement of an epidural spinal cord electrode array for functional restoration in people with paraplegia
Authors: Schöfer Patrick , Lente Kornelius , Wegner Celine , Kogut Andreas , Rupp Rüdiger , Krüger Thilo B. 
Published: December 2021

Abstract
Targeted stimulation of dorsal nerve roots of the lumbosacral spinal cord (SC) represents a promising way to improve lower extremity functions for people with paraplegia due to SC injury. Stimulation pulses are selectively applied at different segments of the SC by means of an implanted electrode array. For an optimal clinical outcome, correct positioning of the array in rostrocaudal and mediolateral direction of the SC is essential. We developed a neuromonitoring framework to support the neurosurgeon during the implantation procedure by automated stimulation and real-time analysis of evoked muscular responses. For the implementation we developed and combined a new software with several hardware and software modules for intraoperative neuromonitoring. The new software coordinates different interfaces and components including a neurostimulator, a multiplexer module and a biosignal amplifier. In addition, a graphical user interface (GUI) was implemented, allowing control of the system and display of analyzed data. With the framework, stimulation sequences in respect to stimulation amplitudes and selection of contacts of the electrode array can be predefined and executed in an automated manner. Synchronously the evoked electromyographic responses of the target muscles can be recorded, analyzed and displayed together with the stimulation setup for visual evaluation. The framework serves as a fundamental basis for the integration of a clinical knowledge-based algorithm and the realization of a future neuromonitoring system for this purpose.
How Multimodal Examinations Can Increase Sustainable Student Gain by Aligning Teaching and Assessment
Authors: Gundlach Michael , Baumann Martin , Engelmann Ulrich M. 
Published: December 2021

Abstract
Modern industry and multi-discipline projects require highly trained individuals with resilient science and engineering back-grounds. Graduates must be able to agilely apply excellent theoretical knowledge in their subject matter as well as essential practical “hands-on” knowledge of diverse working processes to solve complex problems. To meet these demands, university education follows the concept of Constructive Alignment and thus increasingly adopts the teaching of necessary practical skills to the actual industry requirements and assessment routines. However, a systematic approach to coherently align these three central teaching demands is strangely absent from current university curricula. We demonstrate the feasibility of implementing practical assessments in a regular theory-based examination, thus defining the term “blended assessment”. We assessed a course for natural science and engineering students pursuing a career in biomedical engineering, and evaluated the benefit of blended assessment exams for students and lecturers. Our controlled study assessed the physiological background of electrocardiograms (ECGs), the practical measurement of ECG curves, and their interpretation of basic pathologic alterations. To study on long time effects, students have been assessed on the topic twice with a time lag of 6 months. Our findings suggest a significant improvement in student gain with respect to practical skills and theoretical knowledge. The results of the reassessments support these outcomes. From the lecturers´ point of view, blended assessment complements practical training courses while keeping organizational effort manageable. We consider blended assessment a viable tool for providing an improved student gain, industry-ready education format that should be evaluated and established further to prepare university graduates optimally for their future careers.
Finding an optimal dictionary of different wavelet types using sparse modeling to denoise ECG signal
Authors: Samann Fars , Schanze Thomas 
Published: December 2021

Abstract
Sparse signal modeling often reconstructs a signal with few atoms from a pre-defined dictionary. Hence the choice of wavelet dictionary that represents the sparsity of the target signal is crucial in sparse modeling approach. The challenge of finding an optimal dictionary of different wavelet types using sparse denoising model (SDM) to denoise ECG signal is investigated in this work. A method of finding an optimal wavelet dictionary from a set of orthogonal wavelet sub-dictionaries by the means of the best correlation with ECG signal, is developed. The highly correlated sub-dictionaries from three wavelet dictionaries, namely daubechies, symlets, coiflets and discrete cosine transform are combined to construct an overcomplete dictionary. The weight of Akaike’s information criterion and the signal-to-noise ratio improvement are considered as a criterion to evaluate the performance of the proposed SDM. The results indicate that multi-wavelet dictionary of different types is highly sparse and efficient in denoising the target signal, e.g., ECG.