bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of Successful Ultrasound-Accelerated Catheter-Directed Thrombolysis with Postthrombotic Syndrome: A Post Hoc Analysis of the CAVA Trial
Authors: Notten Pascale , Arnoldussen Carsten W. K. P. , Brans Rutger , de Smet André A. E. A. , Tick Lidwine W. , van de Poel Marlène H. W. , Wikkeling Otmar R. M. , Vleming Louis-Jean , Koster Ad , Jie Kon-Siong G. , Jacobs Esther M. G. , Ebben Harm P. , Planken Nils , ten Cate Hugo , Wittens Cees H. A. , ten Cate-Hoek Arina J.
Published: June 2020

Background The CAVA trial did not show the anticipated risk reduction for postthrombotic syndrome (PTS) after thrombus removal via additional ultrasound-accelerated catheter-directed thrombolysis (UACDT) in patients with acute iliofemoral deep vein thrombosis (IFDVT). Difficulties in achieving an effective degree of recanalization through thrombolysis may have influenced outcomes. We therefore assessed whether successful UACDT (restored patency ≥ 90%) did reduce the development of PTS.

Methods This CAVA trial post hoc analysis compared the proportion of PTS at 1-year follow-up between patients with successful UACDT and patients that received standard treatment only. In addition, clinical impact as well as determinants of successful thrombolysis were explored.

Results UACDT was initiated in 77 (50.7%) patients and considered successful in 41 (53.2%, interrater agreement κ = 0.7, 95% confidence interval 0.47–0.83). PTS developed in 15/41 (36.6%) patients in the successful UACDT group versus 33/75 (44.0%) controls (p = 0.44). In this comparison, successful UACDT was associated with lower Venous Clinical Severity Score (3.50 ± 2.57 vs. 4.82 ± 2.74, p = 0.02) and higher EuroQOL-5D (EQ-5D) scores (40.2 ± 36.4 vs. 23.4 ± 34.4, p = 0.01). Compared with unsuccessful UACDT, successful UACDT was associated with a shorter symptom duration at inclusion (p = 0.05), and higher rates of performed adjunctive procedures (p < 0.001) and stent placement (p < 0.001).

Conclusion Successful UACDT was not associated with a reduced proportion of PTS 1 year after acute IFDVT compared with patients receiving standard treatment alone. There was, however, a significant reduction in symptom severity and improvement of generic quality of life according to the EQ-5D. Better patient selection and optimization of treatment protocols are needed to assess the full potential of UACDT for the prevention of PTS.

Trial Registration Number ClinicalTrials.gov number, NCT00970619.
Intraoperative Lumbar Drain Placement in Endoscopic Neurosurgical Procedures: Technical Challenges and Complications—A Prospective Observational Study
Authors: Koshy Mridul S. , Singh Georgene , Yadav Bijesh , Mariappan Ramamani , Pappachan Liby G. ,   Krishnaprabhu
Published: June 2020

Background Perioperative placement of lumbar drain (LD) is being increasingly preferred in the endoscopic base of skull procedures to provide optimal surgical conditions. This study aims to determine the incidence of technical difficulties and complications associated with LD placement.

Materials and Methods A total of 50 patients undergoing transnasal transsphenoidal surgery were included in the study after obtaining written informed consent. Intraoperatively, LD was placed using an 18-gauge epidural catheter. Technical difficulties in LD placement were assessed by the number of attempts, levels attempted, difficulty in siting catheter, and obtaining free flow of cerebrospinal fluid (CSF). The incidence of complications such as postdural puncture headache (PDPH), meningitis headache, and backache was studied.

Results Successful LD placement in the first attempt was obtained in 36% of the patients. Technical difficulties were encountered in 64% of the patients. Despite successful LD placement in 90% of the patients, 32% required manipulations to increase CSF flow. The drain failure rate was 10%. Drainage of >20 to 30 mL of CSF/hour was significantly associated with better surgical conditions (p < 0.05). The incidence of headache was 56% and that of backache was 26%. Headache was significantly related to difficulty in tapping CSF (p = 0.032), and backache was significantly related to the number of attempts (p < 0.001), levels attempted (p = 0.001), and large CSF volume (p = 0.004). There were no incidences of PDPH or meningitis in our series.

Conclusion We conclude that the incidence of technical difficulties in LD placement with epidural catheters is high. Use of standard well-functioning LD catheters will assist in improving surgical conditions.
Gastrointestinal and Liver Manifestations of COVID-19
Authors: Taneja Sunil , Mehtani Rohit , Chawla Yogesh Kumar
Published: June 2020

A novel Coronavirus, SARS-CoV-2 illness, has spread throughout the world after the first case was reported from Wuhan, China, in December 2019. This illness typically causes respiratory symptoms like fever, cough, and shortness of breath, although atypical presentation with gastrointestinal symptoms like abdominal pain, nausea, vomiting, or diarrhea are being increasingly reported. The viral RNA has been detected in saliva and stool of such patients, which raises concerns regarding the risk of transmission during gastrointestinal (GI) endoscopy. Many patients also have liver involvement, with the most common manifestation being deranged liver function tests. This review highlights the symptomatology, mechanism, and histopathology findings of SARS-CoV-2 in GI tract and liver. This review also focuses on implications of COVID-19 in patients afflicted with chronic liver disease and in patients undergoing liver transplantation.
Toward rapid infectious disease diagnosis with advances in surface-enhanced Raman spectroscopy
Authors: Tadesse Loza F. , Safir Fareeha , Ho Chi-Sing , Hasbach Ximena , Khuri-Yakub Butrus (Pierre) , Jeffrey Stefanie S. , Saleh Amr A. E. , Dionne Jennifer
Published: June 2020

In a pandemic era, rapid infectious disease diagnosis is essential. Surface-enhanced Raman spectroscopy (SERS) promises sensitive and specific diagnosis including rapid point-of-care detection and drug susceptibility testing. SERS utilizes inelastic light scattering arising from the interaction of incident photons with molecular vibrations, enhanced by orders of magnitude with resonant metallic or dielectric nanostructures. While SERS provides a spectral fingerprint of the sample, clinical translation is lagged due to challenges in consistency of spectral enhancement, complexity in spectral interpretation, insufficient specificity and sensitivity, and inefficient workflow from patient sample collection to spectral acquisition. Here, we highlight the recent, complementary advances that address these shortcomings, including (1) design of label-free SERS substrates and data processing algorithms that improve spectral signal and interpretability, essential for broad pathogen screening assays; (2) development of new capture and affinity agents, such as aptamers and polymers, critical for determining the presence or absence of particular pathogens; and (3) microfluidic and bioprinting platforms for efficient clinical sample processing. We also describe the development of low-cost, point-of-care, optical SERS hardware. Our paper focuses on SERS for viral and bacterial detection, in hopes of accelerating infectious disease diagnosis, monitoring, and vaccine development. With advances in SERS substrates, machine learning, and microfluidics and bioprinting, the specificity, sensitivity, and speed of SERS can be readily translated from laboratory bench to patient bedside, accelerating point-of-care diagnosis, personalized medicine, and precision health.
Magnetoconductivity oscillations induced by intersubband excitation in a degenerate 2D electron gas
Authors: Monarkha Yu. P.
Published: June 2020

Magnetoconductivity oscillations and absolute negative conductivity induced by nonequilibrium populations of excited subbands in a degenerate multisubband two-dimensional electron system are studied theoretically. The displacement from equilibrium, which can be caused by resonant microwave excitation or by any other reason, is assumed to be such that electron distributions can no longer be described by a single Fermi level. In this case, in addition to the well-known conductivity peaks occurring at the Shubnikov-de Haas conditions and small peaks of normal intersubband scattering, sign-changing oscillations with a different shape are shown to be possible. We found also that even a small fraction of electrons transferred to the excited subband can lead to negative conductivity effects.
Raman scattering during a magnetic phase transition in a LiNiPO4 single crystal
Authors: Peschanskii A. V.
Published: June 2020

The temperature evolution of the LiNiPO4 single crystal Raman spectra in a region of 2–25 K, which includes a phase transition to a magnetically ordered state, is studied. For the first time, magnetic contribution in the Raman spectra was divided into single-magnon and two-magnon excitations at 2 K. The energies of the detected single-magnon excitations are in good agreement with the data obtained earlier from transmission spectra in the near-IR region. The shape of the two-magnon scattering band corresponds to the published data for the density of two-magnon states. A shift in some phonon lines was detected in the transition to a magnetically ordered state, which indicates a significant magnon-phonon interaction. A change in the scattering spectrum intensities below TN was observed, which depends on the polarization of the incident light. It is suggested that this effect is associated with a shift of the Ni2+-ion absorption bands during magnetic ordering in the region of the 532 nm excitation line. This indicates a significant interaction between the electronic and magnetic subsystems in the crystal under study.
Magnetoelectric coupling in a frustrated spinel studied using high-field scanning probe microscopy
Authors: Rossi L. , Brüning D. , Ueda H. , Skourski Y. , Lorenz T. , Bryant B.
Published: June 2020

Below its Neél temperature, the frustrated magnet CdCr2O4 exhibits an antiferromagnetic spin-spiral ground state. Such states can give rise to a sizable magnetoelectric coupling. In this report, we measure the electric polarization induced in single-crystalline CdCr2O4 by large applied magnetic field. Because the detection of a macroscopic polarization is hindered by the structural domains in the tetragonal spin-spiral phase, we have pioneered an alternative method of measuring polarization induced by high magnetic fields, using electrostatic force microscopy. This method enables us to measure polarization from nanoscale areas of the sample surface, as well as imaging how charge inhomogeneities change with magnetic field.
Gas density structure of supersonic flows impinged on by thin blades for laser–plasma accelerator targets
Authors: Fan-Chiang L. , Mao H.-S. , Tsai H.-E. , Ostermayr T. , Swanson K. K. , Barber S. K. , Steinke S. , van Tilborg J. , Geddes C. G. R. , Leemans W. P.
Published: June 2020

Density transition injection is an effective technique for controllably loading electrons into a trapped phase for laser plasma accelerators. One common technique to achieve the required fluid structure is to impinge a thin blade on the plume of a supersonic nozzle. Density transitions induced in this way are often assumed to be bow shocks and therefore sharp, but simulations and fluorescence measurements presented in this work show that in many cases of interest, the density transition accessible to a laser propagating transverse to the shock is an intercepting shock, and therefore, shock thickness and density vary with pressure, laser height, and blade position. The fluid dynamics of a supersonic nozzle impinged on by a thin, flat object are explored through simulations and relevant features are verified via planar laser-induced fluorescence measurements. The implications of the results for tuning electron beam injectors in laser plasma accelerators are discussed.
Optimal photonic nanojet beam shaping by mesoscale dielectric dome lens
Authors: Lin C. B. , Lee Yi-Ting , Liu Cheng-Yang
Published: June 2020

In this work, we thoroughly investigate the shape, size, and location of the photonic nanojets (PNJs) generated from the illuminated dome lens. The silk fiber is directly extracted from the cellar spider and used to form the dome lens by its liquid-collecting ability. The solidified dielectric dome lenses with different dimensions are obtained by using ultraviolet curing. Numerical and experimental results show that the long PNJs are strongly modulated by the dimension of the dome lens. The optimal PNJ beam shaping is achieved by using a mesoscale dielectric dome lens. The PNJ with a long focal length and a narrow waist could be used to scan over a target for large-area imaging. The silk fiber with a dome lens is especially useful for bio-photonic applications by combining its biocompatibility and flexibility.
Surface control and MBE growth diagram for homoepitaxy on single-crystal AlN substrates
Authors: Lee Kevin , Cho YongJin , Schowalter Leo J. , Toita Masato , Xing Huili Grace , Jena Debdeep
Published: June 2020

The evolution of surface morphology for single-crystal bulk Al-polar aluminum nitride substrates during ex situ cleaning, in situ cleaning, and subsequent homoepitaxy is investigated. Ex situ acid treatment is found to reveal atomic steps on the bulk AlN substrates. After in situ Al-assisted cleaning at high temperatures in a high vacuum environment monitored with reflection high-energy electron diffraction, cleaner atomic step edges are observed. Subsequent growth on the cleaned bulk AlN by molecular beam epitaxy is used to develop a phase-diagram for homoepitaxy on AlN single crystals. Secondary ion mass spectrometry profiles reveal high-purity epitaxial layers with undesired chemical impurity densities of Si, O, and C to be below detection limits. The grown homoepitaxial films are observed to oxidize in the ambient environment, but repeating the ex situ acid treatment again reveals atomic steps.
Modeling the role of respiratory droplets in Covid-19 type pandemics
Authors: Chaudhuri Swetaprovo , Basu Saptarshi , Kabi Prasenjit , Unni Vishnu R. , Saha Abhishek
Published: June 2020

In this paper, we develop a first principles model that connects respiratory droplet physics with the evolution of a pandemic such as the ongoing Covid-19. The model has two parts. First, we model the growth rate of the infected population based on a reaction mechanism. The advantage of modeling the pandemic using the reaction mechanism is that the rate constants have sound physical interpretation. The infection rate constant is derived using collision rate theory and shown to be a function of the respiratory droplet lifetime. In the second part, we have emulated the respiratory droplets responsible for disease transmission as salt solution droplets and computed their evaporation time, accounting for droplet cooling, heat and mass transfer, and finally, crystallization of the dissolved salt. The model output favourably compares with the experimentally obtained evaporation characteristics of levitated droplets of pure water and salt solution, respectively, ensuring fidelity of the model. The droplet evaporation/desiccation time is, indeed, dependent on ambient temperature and is also a strong function of relative humidity. The multi-scale model thus developed and the firm theoretical underpinning that connects the two scales—macro-scale pandemic dynamics and micro-scale droplet physics—thus could emerge as a powerful tool in elucidating the role of environmental factors on infection spread through respiratory droplets.
Visualizing the effectiveness of face masks in obstructing respiratory jets
Authors: Verma Siddhartha , Dhanak Manhar , Frankenfield John
Published: June 2020

The use of face masks in public settings has been widely recommended by public health officials during the current COVID-19 pandemic. The masks help mitigate the risk of cross-infection via respiratory droplets; however, there are no specific guidelines on mask materials and designs that are most effective in minimizing droplet dispersal. While there have been prior studies on the performance of medical-grade masks, there are insufficient data on cloth-based coverings, which are being used by a vast majority of the general public. We use qualitative visualizations of emulated coughs and sneezes to examine how material- and design-choices impact the extent to which droplet-laden respiratory jets are blocked. Loosely folded face masks and bandana-style coverings provide minimal stopping-capability for the smallest aerosolized respiratory droplets. Well-fitted homemade masks with multiple layers of quilting fabric, and off-the-shelf cone style masks, proved to be the most effective in reducing droplet dispersal. These masks were able to curtail the speed and range of the respiratory jets significantly, albeit with some leakage through the mask material and from small gaps along the edges. Importantly, uncovered emulated coughs were able to travel notably farther than the currently recommended 6-ft distancing guideline. We outline the procedure for setting up simple visualization experiments using easily available materials, which may help healthcare professionals, medical researchers, and manufacturers in assessing the effectiveness of face masks and other personal protective equipment qualitatively.
Ocean mixing and heat transport processes observed under the Ross Ice Shelf control its basal melting
Authors: Stevens Craig , Hulbe Christina , Brewer Mike , Stewart Craig , Robinson Natalie , Ohneiser Christian , Jendersie Stefan
Published: June 2020

Significance

This study describes measurements of the ocean beneath the center of the Ross Ice Shelf, the Earth’s largest ice shelf. Ice shelves experience melting from below by the ocean and so are vulnerable to a warming climate system. We present the second dataset ever collected from this region, the first having been gathered 40 y prior. Our data provide a basis for better understanding the complex processes that drive melting. They illustrate the degree of variability in the mid-water column, a region largely ignored in modeling. We also observed ephemeral refreezing on the ice shelf underside, with implications for both melt rate and upper ocean dynamics. This insight emphasizes the importance of in situ observations in undersampled environments.
Weather at the winter and stopover areas determines spring migration onset, progress, and advancements in Afro-Palearctic migrant birds
Authors: Haest Birgen , Hüppop Ommo , Bairlein Franz
Published: June 2020

Significance

Migratory birds show alarming declines across the globe, especially birds that migrate over long distances. A limited ability to adjust spring arrival to climate change at the breeding grounds, especially compared to residents and shorter-distance migrants, is thought to be a major cause. Our results show that breeding area arrival of cross-continental migrant birds is nevertheless, similarly to short-distance migrants, largely driven by weather conditions at the wintering and stopover grounds. Additionally, our study indicates that not only temperature rise but also more favorable wind conditions have allowed birds to arrive earlier. A better understanding of climate change influences on the timing of biological phenomena is vital to understanding and ultimately battling the consequences of climate change on population demographics.
Functional variation of lexical bundles in academic lectures and TED talks
Authors: Liu Chen-Yu , Chen Hao-Jan Howard
Published: June 2020

This study explores the differences between academic lectures and TED talks by comparing their respective frequent four-word lexical bundles, and the discourse functions of those bundles in these two registers. The results indicate that academic lectures use more varied lexical bundles at a higher frequency than TED talks do. The functional distributions of the bundles further reveal that referential bundles are prevalent in both registers. However, TED speakers use more lexical bundles to organize their discourse and to guide the audience through their talks, while academic lecturers use more stance bundles to show their intentions and to inform the audience about upcoming events. The distinctive characteristics of academic lectures and TED talks are revealed via the divergent sets of lexical bundles in the two registers; the two registers are also shown to differ greatly in terms of the use of lexical bundles for different functions.
Turkish heritage speakers in
Germany
Authors: Daller Michael
Published: June 2020

In the present chapter,
first, the migration background of Turkish
heritage speakers in Germany will be described.
Secondly, the available literature on Turkish
heritage speakers with a focus on vocabulary will
be discussed. Finally, the results of a recent
study on heritage speakers will be presented. The
present study supports the findings of previous
studies which aim to answer the question whether
there is a vocabulary gap in bilinguals, such that
bilinguals have smaller vocabularies than
monolinguals. A deficit or gap is attested for
bilinguals in a number of studies when they are
compared with monolingual control groups (for a
detailed overview see Thordardottir, 2011).
However, this gap seems to be an artefact of the
methodology since bilinguals use their two
languages in different domains (Grosjean, 1982,
2001, 2015) and almost never develop a
vocabulary in both of their languages that is
comparable to monolinguals. We therefore need to
include both languages in an investigation of a
potential bilingual vocabulary gap. However, even
when both languages are investigated, a deficit in
vocabulary knowledge, especially productive
vocabulary is attested in many studies (for a
detailed discussion see Daller & Ongun, 2017).
Because the literature presents somewhat
inconclusive results, in this study, we wanted to
test whether or not the productive vocabulary of a
bilingual individual group also shows a gap when
compared to monolingual controls. The present
study is based on picture descriptions of 23
heritage speakers and two control groups for
German (n = 18) and Turkish
(n = 30). We take both languages
into account to obtain a fine-grained picture of
the bilingual proficiency of the heritage speakers
in our sample. A vocabulary gap can be identified
for Turkish but not for German. When the
children’s total conceptual vocabulary (Pearson, Fernández,
& Oller, 1993) is considered, however,
there is no vocabulary gap for this group of
bilinguals.
First language exposure predicts attrition
patterns in Turkish heritage speakers’ use of
grammatical evidentiality
Authors: Arslan Seçkin , Bastiaanse Roelien
Published: June 2020

This chapter reports on a
preliminary study examining the production of
grammatical evidentiality forms in narrative
speech samples elicited from heritage language
speakers (HLS) of Turkish. Turkish grammatically
marks direct and indirect sources of evidence one
has for their statement. We explored (1) how
Turkish HLS use evidentiality marking as compared
to monolingual Turkish speakers, and (2) which
factors predict their performances in producing
evidentiality. Our findings showed that the HLS
made a large number of contextually inappropriate
substitutions by using direct evidentials in
places where an indirect evidential would be used,
and that this pattern is largely predicted by the
amount of self-reported exposure to the first
(heritage) language in daily life.
Investigating the effects of L1 proficiency
and CLI
Authors: Krause Elif , Rinker Tanja , Eulitz Carsten
Published: June 2020

This paper investigates the
effects of cross-linguistic influence (CLI) in L1
Turkish of Turkish-German bilingual speakers. The
study examines whether overlapping structures in
the two languages result in influences of the
dominant L2 German on the weaker L1 Turkish in
morphosyntactic processing. Plural-marking on noun
phrases was chosen for investigation since it
provides an ideal test case and it constitutes
partial overlap in German and Turkish. Since
various definitions of CLI describe effects of
this phenomenon that relate to language
processing, behavioral measures are utilized in
this research. The analyses of accuracy rates
reveal that the two languages are clearly
differentiated from each other. However, the
bilingual speakers perform better with respect to
the construction, which is only available in
Turkish, compared to the overlapping structure
between the languages. This indicates that the
speakers separate the two languages from each
other. However, interlanguage cue competition is
at play in morphosyntactic processing in the L1
heritage language. The effects of heritage
language proficiency are also examined by means of
comparing high- and low-to-intermediate heritage
speakers. The proficiency effects on L1 processing
can be found in processing speed but not in
accuracy rates. High-to-intermediate speakers do
not differ from monolinguals in their processing
speed, whereas the low-to-intermediate speakers
perform slower than both the monolinguals and the
high-to-intermediate heritage speakers. We discuss
these findings within Modular Online Growth and
Use of Language (MOGUL), which is a
processing-based linguistic framework that
accounts for the interaction of the two languages
in the bilingual mind.
Contemporary urban Turkey-Turkish in the
German-Turkish classroom
Authors: Erduyan Işil
Published: June 2020

Drawing on a larger
linguistic ethnographic project (Erduyan,
2019), this chapter focuses on the
incorporation of urban, Turkey-Turkish speech
style into the Turkish heritage language classroom
discourse in the context of Germany. Adopting a microethnographic framework through scalar lenses, the analyses center on naturally occurring word search sessions in two different Turkish classes. The foci of analyses are on two
adjectives that have gone through semantic
widening in Turkey-Turkish in recent years
(komik, arızalı) and are
incorporated into teacher-led classroom
discussions. Findings demonstrate that the newly
attributed meanings of these adjectives in context
are not equally transparent to the teachers and
students alike; and the Turkish-German
transnational scale that gets constructed in a
diversity of ways across the students and the
teachers seems to play a role in this
difference.
Influence of species and processing parameters on recovery and content of brain tissue‐derived extracellular vesicles
Authors: Huang Yiyao , Cheng Lesley , Turchinovich Andrey , Mahairaki Vasiliki , Troncoso Juan C. , Pletniková Olga , Haughey Norman J. , Vella Laura J. , Hill Andrew F. , Zheng Lei , Witwer Kenneth W.
Published: June 2020

Extracellular vesicles (EVs) are involved in a wide range of physiological and pathological processes by shuttling material out of and between cells. Tissue EVs may thus lend insights into disease mechanisms and also betray disease when released into easily accessed biological fluids. Since brain‐derived EVs (bdEVs) and their cargo may serve as biomarkers of neurodegenerative diseases, we evaluated modifications to a published, rigorous protocol for separation of EVs from brain tissue and studied effects of processing variables on quantitative and qualitative outcomes. To this end, size exclusion chromatography (SEC) and sucrose density gradient ultracentrifugation were compared as final separation steps in protocols involving stepped ultracentrifugation. bdEVs were separated from brain tissues of human, macaque, and mouse. Effects of tissue perfusion and a model of post‐mortem interval (PMI) before final bdEV separation were probed. MISEV2018‐compliant EV characterization was performed, and both small RNA and protein profiling were done. We conclude that the modified, SEC‐employing protocol achieves EV separation efficiency roughly similar to a protocol using gradient density ultracentrifugation, while decreasing operator time and, potentially, variability. The protocol appears to yield bdEVs of higher purity for human tissues compared with those of macaque and, especially, mouse, suggesting opportunities for optimization. Where possible, perfusion should be performed in animal models. The interval between death/tissue storage/processing and final bdEV separation can also affect bdEV populations and composition and should thus be recorded for rigorous reporting. Finally, different populations of EVs obtained through the modified method reported herein display characteristic RNA and protein content that hint at biomarker potential. To conclude, this study finds that the automatable and increasingly employed technique of SEC can be applied to tissue EV separation, and also reveals more about the importance of species‐specific and technical considerations when working with tissue EVs. These results are expected to enhance the use of bdEVs in revealing and understanding brain disease.
Characterization of antioxidant from daunkemangi (Ocimum sanctum) extracted using ultrasonic bath
Authors: nasution H , Wijaya F , Ellsworth
Published: June 2020

The antioxidant properties of Ocimumsanctum extract were characterized. The extract was prepared by extraction using ultrasonic bath at 50 °C for 30 minutes. The characterization was performed using FT-IR analysis.The phytochemical assays were carried out using various reagents. The results confirmed the presence of phenolics, flavanones, flavonoids, steroids and terpenoids in the extract. The DPPH assay also showed the antioxidant radical scavenging activity by percentage of inhibition of 57.95%.
Effect of Impeller Types on Saponification Reaction Using Stirred Tank Reactor
Authors: Hasibuan R , Parsaulian R R , Adventi F , Manurung R , Hidayati J
Published: June 2020

The choice of impeller type is an important factor in maximizing the performance of a stirred tank reactor in saponification process. This study aims to determine the type of impeller that can produce the highest reaction rate by taking into account changes in alkali concentration in saponification reactions so as to obtain a shorter residence time. The saponification process was carried out by reacting 30% oil with alkali (KOH) at operating conditions 70°C, stirring speed of 400 rpm for 45 minutes using 4 types of impellers namely paddle-2 blades, pitch blade turbine 45°-2 blades, paddle-4 blades, pitch blade turbine 45°-4 blades. Testing of alkali concentration was carried out every 5 minutes until the reaction was complete. Alkali concentration was obtained at the end of the reaction using a paddle-2 bladesimpeller of 0.182 M with a conversion of 97.35%, a pitch blade turbine 45°-2 bladesof 0.142 M with a conversion of 97.93%, paddle-2 bladesof 0.106 M with conversion of 98.46%, pitch blade turbine 45°-4 blades of 0.100 M with conversion of 98.54%.
Design of Interactive Virtual Reality for Erection Steel Construction Simulator System Using Senso Gloves
Authors: Nainggolan F , Siregar B , Fahmi F
Published: June 2020

In steel construction, some stages demand a learning process first to understand the functions and procedures that will occur. The erection process in steel construction is a process of assembling steel components so that it becomes a unity that will be carried out in the field. When carrying out steel as part of erection activities, there are huge potential risks to employees, subcontractors, or other personnel within the construction area, therefore it requires intensive training before real work done. Various methods can be done to facilitate the teaching of the erection process in steel construction; one of them is by using a simulator. A simulator system that uses hand gesture readings and haptic feedback is the best choices of learning methods to help the learning process of erection in steel construction. Virtual reality is an option to be applied the desired simulator system. With virtual reality, users can utilize cognitive and motor skills to interact with the system. The cognitive and motor skills are increasingly driven by control devices like senso gloves that can read and display the motion at the system interface in the same time. In addition, the addition of haptic feedback in the form of vibrations at each fingertip of the glove makes the simulation closer to reality. The purpose of this study is to design the use of motion control Senso Glove as a tool in developing simulator for the erection process learning in steel construction within a virtual reality environment.
Comparison of The Effect of Steel Slag Usage As a Fine Aggregate Against Compressive Strength And Flexture on Reinforced Concrete With Normal Concrete (Experimental Study)
Authors: Karolina R , Gaol T A M L
Published: June 2020

One key element in that development is concrete. The basic ingredients of concrete is a mixture of cement, water, fine aggregate and coarse aggregate, while the concrete using steel reinforcement called reinforced concrete. The times in the era of rapid globalization have resulted in increasing number of second-hand goods / waste can be a problem for the existence of life, one of which is the existence of waste steel slag. To that end, much has been done in order to recycle in order to overcome the problem of the existence of this waste. One way is to capitalize upon such waste for purposes that could be used. In this study, the steel slag is used as a substitute or substitutes in normal concrete mix. Variations addition of steel slag at normal concrete to determine the compressive strength and flexural strength better and is expected to improve the quality of the concrete form of the compressive strength and strong bending. The variation of the addition of steel slag used was 0%, 15%, 25%, and the testing was done by the compressive strength and flexural strength. From the test results obtained by the resulting increase in the value of the slump, the increase in the compressive strength and increased compressive strength lentur. The increase in the capacity of steel slag respectively 11.91% and 20.35%, of normal concrete. Whereas the increase in the flexural strength of steel slag substitution respectively 16.62% and 31.18% of normal concrete. Therefore, if conducted further research it is better grades of steel slag enlarged variation of more than 25% in order to be used as a substitute. Continued research for high quality concrete can be done by mixing a solution that can increase the holding capacity of steel slag with other concrete constituent materials.
Diversity of Reef Fish in Tapian Nauli Bay, Central Tapanuli
Authors: Fadhilah A , Harahap Z A
Published: June 2020

Tapian Nauli Bay is along the coast of Sibolga Bay starting from the border of Sibolga City towards Barus, Tapanuli Tengah. In the Tapian Nauli Bay area there are plenty of fish biological resources and coral reef ecosystems. It is known that the reef fish community is a biotic component of the coral reef ecosystem that can be utilized as marine biological resources.This study aims to examine the diversity of reef fish. The method used in monitoring reef fish is a method Underwater Visual Census (UVC).The reef fishes observed were then grouped into 3 groups of fish, namely: target species, indicator species, and major species, then the structure of the reef fish community was calculated. The results showed that the composition of reef fish species in Sitardas Beach and Bakar island was dominated by major fish (97%), then followed by target fish (2%) and indicator fish (1%).And, overall the diversity of reef fish species in the Sitardas Beach and Bakar island waters shows a low level and shows a relatively unstable uniformity level.
The Use of Virtual Reality Controllers and Comparison Between Vive, Leap Motion and Senso Gloves Applied in The Anatomy Learning System
Authors: Tanjung K , Nainggolan F , Siregar B , Panjaitan S , Fahmi F
Published: June 2020

The availability of control devices that use hand and finger movements in virtual reality systems has an essential role in increasing the level of interaction in the virtual reality system. Hand and finger movements in a virtual reality system can be displayed either in the form of a controller that resembles its original shape or in the form of a virtual hand. The translation motion and rotation of the virtual reality controller can be used as input to the system. In addition, the virtual reality controllers allow the use of buttons or gestures as triggers on the system. Input in the form of translational and rotational movements on the virtual reality controller and its triggers can be applied to anatomical learning systems in a virtual reality environment. Virtual reality controller has a role as a system control tools. Different virtual reality controllers have different levels of feasibility to the system, similarity when used, and ease of learning. Therefore a comparison was performed on three virtual reality controllers that have different usage methods and features. The three tools chosen in this study are the VIVE Controller, Leap Motion Controller, and Senso Glove. These three tools have different ways of using and feature, including differences in touching the user or not, triggers in the form of buttons or gestures, and whether or not haptic feedback is available. The analysis of the use and its comparison between these three virtual reality controllers are the outcome of this study.
Marketing Strategy for Kemenyan (Styrax spp.) by Community Around The Protected Area HPHTI of PT. Toba Pulp Lestari
Authors: Azhar I , Riswan  , Chandra R , Aulin F R , Risnasari I
Published: June 2020

Incense is a type of sap produced from kemenyan tree (Styrax spp.) by tapping the wood bark. Incense is one of the vegetative non-timber forests product which categorized to resins group that can be processed and utilized for various uses. The purpose of this study was to determine the marketing strategy of incense by the community around the protected area in PT. Toba Pulp Lestari concession. A SWOT analysis was applied to find the best strategy scenario. The analysis result recommends Strength-Opportunity (SO) is the best marketing strategy to be adopted.
Computational analysis of heat transfer in three types of motorcycle exhaust materials
Authors: Tulus  , Marpaung J.L. , Marpaung T.J. , Suriati
Published: June 2020

The finite element method is one method used in the structural and nonstructural analysis. This paper aims to the simulated of the finite element method on nonstructural problems namely heat transfer. The media used has been a motorcycle exhaust system modeled with COMSOL Multiphysics 5.4 software by combining annealed stainless steel 405 with 35% chrome stainless steel, Beta-21S Titanium, and Carbon II type as a large tube on the exhaust model. The results of computing simulation obtained are that the lowest heat transfer value in Carbon II material type with a heat transfer rate of 325 K.
Study of Corellation between Coral Reef Cover and Abundance of Reef Fish in Poncan Gadang Island Sibolga City
Authors: Harahap Z A , Maulana R M , Usman S
Published: June 2020

Poncan Gadang Island used by people for marine tourism, underwater and fisheries activities. These activities make the island’s area as a ship transportation route and feared the condition of the coral reef ecosystem will be damaged. This research aims to find out the condition of coral reef (life coral), the abundance of reef fish and the corellation between those two variables in Poncan Gadang Island. This research was conducted in June 2018 using Underwater Photo Transect (UPT) and Underwater Visual Cencus (UVC) methods. From the results of this research were found 14 species of reef fish that consists of 5 families and 161 individual fish with 23.96 % coral reef lifeform percentage (damaged category). The corellation between coral reef lifeform and abundance of reef fish is 29.5%, which means showing sufficient or moderate corellation.
Performance of a Photovoltaic Solar Cold Storage
Authors: Ambarita H , Sitanggang C , Sipayung R
Published: June 2020

Energy is an element of a very important need and can not be separated from human life, especially electrical energy, electrical energy is energy that is widely used and can not be separated from everyday life. In this technological era, the need for electrical energy continues to grow with the development of technology. The energy source for power generation in Indonesia is largely supplied from fossil energy (combustion energy), but these energy sources will be exhausted within about 20 years. Various studies have now led to the development of alternative energy sources such as nuclear energy, solar energy (solar energy), water energy, wind energy, biomass energy, geothermal energy and wave energy. The use of engine coolant in this era has widened where refrigeration is not only applied to household needs, but can also be applied to the needs of industry such as the pharmaceutical industry and the fishing industry as fishermen at sea takes time from weeks to months. The cold storage’s performance analysis aims to determine the best condition of the cooling engine with a variation of 5 photovoltaic units with 250 WP per unit. From the test results obtained daily average performance at 3:32 with testing carried out for 9 hours.
Isolation And Characterization Of Flavonoid From Leaves Of Bauhinia kockiana Lour And Antibacterial Activity
Authors: Pasaribu A , Nurtjahja K
Published: June 2020

The Isolation and purification of flavonoid compounds from the leaves of Bauhinia kockiana Lour had been done. Concentrated methanol extract was hydrolyzed with HCl 6%, partitioned with chloroform and it was separated by column chromatography using n-hexane: ethyl acetate (60:40 v/v). Pure yellow-crystalline amorphous compound; mass = 33.8 mg, m.p = 155 °C and Rf = 0.29, was then characterized by spectroscopy UV-Visible, FT-IR and 1H-NMR. Interpretation of Spectrofotometer of compound compared with data standard showed the compound is flavonoid Flavonol. The antibacterial activity test toward methanol, hexane and ethyl acetate extracts respectively was conducted using diffusion method which inoculated bacteria were dipped into Mueller Hinton Agar. Results showed that inhibitory effect of bacterial growth was better with effective inhibition zone againsts Escherichia coli at concentration 500 mg/ml with diameter zone 17.8 mm
Soil Compaction Study Due to 4 Wheel Tractor Track in PTPN II Kulmpang Sugar Cane Plantation
Authors: Rizaldi T , Susanto E , Napitupulu R P
Published: June 2020

Soil compaction can occur due to repeated tractor trajectories in the tillage process. Changes in soil physical and mechanical properties that occur can be seen with changes in soil bulk density, soil porosity, ground pressure and soil penetration resistance. Soil compaction can cause disruption of plant root growth that will reduce crop production. The purpose of this study was to evaluate changes in soil physical and mechanical properties due to soil compaction caused by repeated tractor trajectories. The study was carried out at 20.05% moisture content, bulk density 1.06 gr / cm3 porosity 53.9% and an average penetration resistance of 1.32 kgf/cm2 (0.13 MPa) with an average tractor ground pressure value of 0.88 kg/cm2 crossing the ground as much as 1-8 times the track. The results showed that the number of tractor trajectories affected the value of bulk density, soil porosity and soil penetration resistance. The increasing number of trajectories, causing an increase in the level of soil density which can be seen by increasing the bulk density value by 1.31gr / cm3, decreasing porosity value by 26.63% while the average penetration resistance increases by 6.88 kgf/cm2 (0.67 MPa).
Natural durability of raru wood (Cotylelobium melanoxylon) against subterranean termite attack
Authors: Iswanto A H , Susilowati A , Putra A R , Nopriandi D , Windra E
Published: June 2020

Cotylelobium melanoxylon or locally known as raru is one of the endemic species in North Sumatra. The species was disjunct distributed in Central Tapanuli Regency, North Sumatra. The purpose of this study was to analyze the wood durability of C. melanoxylon against termites’ attack by using the graveyard test method. Wood samples were made measuring 3 cm by 3 cm by 20 cm. The test sample was dried using an oven at 103 ± 2°C for 24 hours before and after the test. The graveyard test was carried out for 3 months (90 days). The test parameter observed was a weight loss of the sample. The results showed that C. melanoxylon wood was classified into durable class II and included in a resistant category with weight loss values ranging from 0.89 to 2.79% for axial direction and 1.81 to 2.22% for lateral direction.
On Some Modular Köthe Vector Valued Sequence Space using φ-Function
Authors: Herawati E , Irsyad N
Published: June 2020

In this paper, we introduce some new modular vector valued sequence spaces defined by φ-function and give some basic result of this space.
Case study of mangrove ecosystem services for tiger shrimp (Penaeus monodon) in the practical silvofishery
Authors: Basyuni M , Indrawan R , Putri L A P , Yusraini E , Lesmana I
Published: June 2020

Mangroves are a particular form of brackish plants, estuaries, and deltas which distributed in tropical and sub-tropical areas. Mangrove has various functions including the ecological functions of mangrove forests such as nesting places, spawning, and enlargement of various types of fish, shrimp, crabs, birds, and other fauna. This study was aimed to determine the mangrove ecosystems service to produce tiger shrimp (Penaeus monodon) in silvofishery ponds that are consisting domination of trees and saplings. Survival of shrimp at trees domination was 0.21% with a total of 125 individual, yielded as much as 1.2 kg. Shrimp survival at saplings domination was 0.31% with a total of 186 individuals, yielded of 1.8 kg. To further increase production results in silvofishery ponds, it is necessary to regulate the techniques of preventing predatory animals that enter the pond when the floodgates are opened, namely by placing a smooth net and repairing the fort.
Effect of concentration starter and fermentation time on the quality of yoghurt drink from buffalo milk
Authors: Sinamo K N , Hasan F , Hasanah U
Published: June 2020

Generally yogurt drinks are made from cow’s milk, whereas buffalo milk has a higher nutrition value than cow’s milk. The objective of this study was to produce yoghurt drinks from buffalo milk and determine proximate composition and sensory quality of the product based on starter concentration and fermentation time. The experiment was carried out using a completely randomized design of factorial patterns consisting two factors, i.e. starter concentration (3, 5 and 10%) and fermentation time (8 and 12 hours). The results of proximate analysis obtained showed starter concentration had significant effect on moisture, fat, protein and carbohydrate contents. While fermentation time had significant effect on fat and protein contents. The sensory evaluation result showed significant differences among the yoghurt drink samples. Sample F (10% starter concentration and 12 hours fermentation time) had the highest scoore in sensory atributes.
Research serendipity: A challenge for changing
Authors: Nasution Mahyuddin K M
Published: June 2020

Research is a part of every activity of human life, and the tri dharma of higher education only reaffirms that task for each academician. Research is not just a coincidence like that, but it is a possibility and opportunity, or not incidentally, for life itself. Because, however, every interest will urge to become the human needs, research becomes a solution so as not to contribute negatively to social and personal well-being. This is stated as research serendipity, which ontologically states that a research will supported by another research and will also give birth to another research.