bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical and experimental studies on broadband photoacoustic response of surface plasmon sensing
Authors: Song Wei , Xiao Sijie , Min Changjun , Fang Hui , Yuan Xiaocong
Published: June 2020

The surface plasmon (SP) sensing technique demonstrates high sensitivity and a broad bandwidth of measuring photoacoustic (PA) pressure transients. In this work, we further present a systematic investigation on PA response characteristics of the recently developed SP-based ultrasonic detector, where the ensemble of surface plasmon polaritons (SPPs) at the metal-dielectric interface is approximated as an equivalent acoustic detector. Relying on the intrinsically ultrafast temporal response (∼140 fs) and highly localized evanescent field (optical penetration depth of ∼185 nm) of the SPPs, the SP sensing can respond ultrasounds with the gigahertz frequency band theoretically, which, however, is far higher than the bandwidth in practical PA detection. We reveal that, due to acoustic interference, the finite lateral probing dimension in the SP sensor imposes an ultimate constraint on the accessible ultrasonic cutoff frequency, representing good agreement with the experimental results by acquiring PA impulses from an optically absorbing graphene film using our SP sensor. The theoretical framework enables analyzing the SP response characteristics of ultrasonic/PA pressure transients, which, therefore, offers guidelines for configuring the SP sensor with adequate sensitivity and bandwidths to access various biomedical PA applications, including volumetric imaging and spectroscopic analysis.
Disintegration of diminutive liquid helium jets in vacuum
Authors: Tanyag Rico Mayro P. , Feinberg Alexandra J. , O’Connell Sean M. O. , Vilesov Andrey F.
Published: June 2020

The phenomenon of liquid jets disintegrating into droplets has attracted the attention of researchers for more than 200 years. An overwhelming fraction of these studies considered classical viscous liquid jets issuing into ambient atmospheric gases, such as air. Here, we present an optical shadowgraphy study of the disintegration of a cryogenic liquid helium jet produced with a 5 µm diameter nozzle into vacuum. The physical properties of liquid helium, such as its density, surface tension, and viscosity, change dramatically as the jet flows through the nozzle and evaporatively cools in vacuum, eventually reaching the superfluid state. In this study, we demonstrate that, at different stagnation pressures and temperatures, droplet formation may involve spraying, capillary breakup, jet branching, and/or flashing and cavitation. The average droplet sizes produced in this work range from 3.4 × 1012 to 6.5 × 1012 helium atoms or 6.7–8.3 µm in diameter. This paper also reports on the distributions of sizes and shapes of the resulting droplets.
Influence of conductivities on electrical breakdown of water under microsecond pulsed voltage
Authors: Liu Si-Wei , Liu Yi , Ren Yi-Jia , Lin Fu-Chang , Li Hua , Zhao Yong
Published: June 2020

A study of the electrical breakdown of water under microsecond pulsed voltages has been performed. The influence of conductivities (350–1550 μS/cm) has been reported in the needle-plate configuration. Both positive and negative applied voltages (10–30 kV) have been adopted to study the streamer propagation and breakdown phenomena. Three streamer modes are observed in our experiment, and the morphologies of streamers at different conductivities are compared. Increasing the conductivity leads to a thinner gaseous layer and stronger luminance for all streamers. However, the polarity effect of the applied voltages causes differences in the mobility of charges in water and results in different propagation velocities. The minimum breakdown voltage at different polarities exhibits different trends for positive subsonic streamers and negative subsonic streamers. This paper has evaluated the shock wave intensity and bubble dynamics after the breakdown of the water gap. The results show that the relationship of the peak pressure (Pm) and the residual energy of the capacitor at the breakdown time (Wb) is consistent and stable. The bubble dynamics and shock wave propagation are less affected by the water conductivity.
Study of the perpendicular magnetic anisotropy, spin–orbit torque, and Dzyaloshinskii–Moriya interaction in the heavy metal/CoFeB bilayers with Ir22Mn78 insertion
Authors: He Congli , Razavi Seyed Armin , Yu Guoqiang , Ma Xin , Wu Hao , Shao Qiming , Wong Kin L. , Shen Shipeng , Zhao Yunchi , Pei Yusen , Chen Qingqiang , Li Xiaoqin , Wang Shouguo , Wang Kang L.
Published: June 2020

The perpendicular magnetic anisotropy (PMA), current-induced spin–orbit torques (SOTs), and Dzyaloshinskii–Moriya interaction (DMI) in the as-grown W or Ta/Ir22Mn78(IrMn)/CoFeB/MgO stacks with varying IrMn layer thicknesses were investigated. The in-plane magnetized W/CoFeB/MgO sample becomes perpendicularly magnetized after inserting the IrMn layer without the requirement of the annealing process. The effective magnetization fields 4πMeff show a nonmonotonic dependence on the IrMn layer thickness, which reaches the maximum in magnitude at a thickness of tIrMn = 0.75 nm. The SOT effective fields corresponding to damping-like and field-like torques decrease with the insertion layer thickness. Moreover, the variation of the IrMn layer thickness leads to the change of the DMI in magnitude and sign change from positive (favoring right-handed chirality) to negative (favoring left-handed chirality). The realization of changing the PMA, SOTs, and DMI by inserting the IrMn layer provides more flexibility in the design of spintronic devices.
Stability of bubble-like fluxons in disk-shaped Josephson junctions in the presence of a coaxial dipole current
Authors: Castro-Montes Alicia G. , Marín Juan F. , Teca-Wellmann Diego , González Jorge A. , García-Ñustes Mónica A.
Published: June 2020

We investigate analytically and numerically the stability of bubble-like fluxons in disk-shaped heterogeneous Josephson junctions. Using ring solitons as a model of bubble fluxons in the two-dimensional sine-Gordon equation, we show that the insertion of coaxial dipole currents prevents their collapse. We characterize the onset of instability by introducing a single parameter that couples the radius of the bubble fluxon with the properties of the injected current. For different combinations of parameters, we report the formation of stable oscillating bubbles, the emergence of internal modes, and bubble breakup due to internal mode instability. We show that the critical germ depends on the ratio between its radius and the steepness of the wall separating the different phases in the system. If the steepness of the wall is increased (decreased), the critical radius decreases (increases). Our theoretical findings are in good agreement with numerical simulations.
Field and fluence dependences of laser-induced multiple spin-wave dynamics in Co2FeAl0.5Si0.5 films
Authors: Chen Zhifeng , Xie Zhikun , Li Shufa , Zhou Jielin , Zhang Wei , Zhang Chengyun , Peng Jun , Chen Jipei , Zhang Bingzhi
Published: June 2020

Field- and fluence-dependent spin-wave dynamics in full-Heusler Co2FeAl0.5Si0.5 films are studied by using time-resolved magneto-optical polar Kerr spectroscopy. Volume magnetostatic spin-wave (VMSW) and perpendicular standing spin-wave (PSSW) modes are excited in the films with thicknesses of 60 and 100 nm, while only the Kittel mode is observed in the films with thicknesses of 150 and 200 nm. The amplitudes of all three spin-wave modes increase with increasing field and fluence, and the frequencies slightly decrease with increasing fluence as expected. The lifetimes and effective damping are found to be modulated by both the external field and excitation fluence. The effective damping of VMSW and Kittel modes presents strong field dependences that are significantly different from each other and can be attributed to the field-dependent group velocity and magnetic inhomogeneity, respectively. In addition, the effective damping of VMSW and PSSW modes increases with increasing fluence, showing a dominant mechanism of electron–phonon scattering enhancement. However, that of the Kittel mode decreases with increasing fluence and further demonstrates the dominant contribution from magnetic inhomogeneity in this case, which is inferred to suppress the excitation of the VMSW mode.
Diversity of solitary electron holes operating with non-perturbative trapping
Authors: Schamel Hans , Mandal Debraj , Sharma Devendra
Published: June 2020

A non-perturbative update of Schamel's pseudo-potential method is employed to show the diversity in structure formation in collisionless plasmas, manifested already in the solitary wave limit. As an example, the Gaussian-shaped solitary electron hole, known from earlier Bernstein, Greene, and Kruskal (BGK) analyses, known to be a specific, albeit incomplete wave solution, is updated by subjecting it to a non-perturbative pseudo-potential analysis. Only by the latter can a speed be assigned to it. A perturbative trapping scenario is thereby defined by a Taylor expansion of the trapped electron distribution function fet with respect to −ϵ, where ϵ:=v22−ϕ(x) is the single particle energy. It stands for the class of privileged, solitary sech4-holes, and properly extends undamped linear waves into the nonlinear regime lifting them at a higher level of reliability. A non-perturbative trapping scenario, on the other hand, cannot be handled by a Taylor expansion as it refers to singular terms in the small ϵ-limit, affecting the collective dynamics in phase space especially near separatrices. Being not only suitable to update BGK solutions, it opens the door to a much richer world of structure formation than treated before. To face physical reality properly, however, one has to go one step further by locally and self-consistently incorporating a structure dependent collisionality in the kinetic description and in the numerical simulation, as well. By this removal of cusp-singularities, associated with reliable Vlasov–Poisson-solutions, a more realistic approach to intermittent plasma turbulence and anomalous resistivity may be achieved in forthcoming investigations.
Terahertz quantum-cascade patch-antenna VECSEL with low power dissipation
Authors: Curwen Christopher A. , Reno John L. , Williams Benjamin S.
Published: June 2020

We report a terahertz quantum-cascade vertical-external-cavity surface-emitting laser (QC-VECSEL) based upon a metasurface consisting of an array of gain-loaded resonant patch antennas. Compared with the typical ridge-based metasurfaces previously used for QC-VECSELs, the patch antenna surface can be designed with a much sparser fill factor of gain material, which allows for reduced heat dissipation and improved thermal performance. It also exhibits larger amplification thanks to enhanced interaction between the incident radiation and the QC-gain material. We demonstrate devices that produce several milliwatts of continuous-wave power in a single mode at ∼4.6 THz and dissipate less than 1 W of pump power. Use of different output couplers demonstrates the ability to optimize device performance for either high power or high operating temperature. Maximum demonstrated power is 6.7 mW at 4 K (0.67% wall-plug efficiency, WPE) and 0.8 mW at 77 K (0.06% WPE). Directive output beams are measured throughout with divergence angles of ∼5°.
Mg diffusion and activation along threading dislocations in GaN
Authors: Yi Wei , Kumar Ashutosh , Uzuhashi Jun , Kimura Takashi , Tanaka Ryo , Takashima Shinya , Edo Masaharu , Yao Yongzhao , Ishikawa Yukari , Chen Jun , Ohkubo Tadakatsu , Sekiguchi Takashi , Hono Kazuhiro
Published: June 2020

The precise control of p-GaN is a crucial issue for developing GaN-based power devices. Mg as an acceptor is commonly used in p-type doping; however, the Mg diffusion through threading dislocations (TDs) has not been well addressed. To clarify the Mg diffusion and activation along TDs, we have performed a systematic characterization of a Mg-implanted homoepitaxial GaN layer grown on a freestanding substrate. Active-Mg related donor–acceptor pair (DAP) emission from certain TDs is identified by cathodoluminescence (CL). Dislocations with and without DAP emission are investigated structurally and compositionally based on etch pits, transmission electron microscopy, and atom-probe tomography. Direct evidence of Mg distribution around edge- and mixed-type TDs is obtained. There exists a significant difference in the Mg concentration and incorporation states between different types of TDs.
The spatial modulation of microfibril angle in the woody tissue of maturing tree stems studied with synchrotron radiation
Authors: Jarrett K. J. , Kirby N. , Buckley C. E. , Garvey C. J.
Published: June 2020

Spatial variations in the microfibril angle (MFA) of cellulose are mapped on individual radial sections of wood from the maturing stems of Australian tree species (Acacia floribunda, Acacia suaveolens, Acacia doratoxylon, Acacia havilandiorum, Brachychiton populneus and Bertya cunninghamii) from different rainfall and soil nutrient availabilities using synchrotron wide angle X-ray scattering. For the three species with the smallest radial variation there is a clear linear relationship between the MFA with Young’s modulus and wood density with data published previously for these samples. The other three samples show a large radially symmetric variation in MFA across the radial section either having a continuous change from large MFA in the stem’s centre to small value close to the bark or the reverse, small MFA at the centre to larger values close to the bark. For these samples, a strong linear correlation between the Young’s modulus and density and the MFA is not apparent. We conclude that spatially localised measurements of MFA provide an important insight in the adaptation of wood tissue to environmental conditions.
Cattle egrets regurgitate house mouse carcasses onto a mouse-free island: implications for rodent eradications
Authors: Shiels Aaron B. , Khalsa Mele , Griffin Doreen L. , Chow Clay K. , Baiao Patty , Mann Sheri S. , Piaggio Antoinette J.
Published: June 2020

Abstract ContextEradication of invasive rodents on islands typically results in positive conservation gains, and maintaining a rodent-free island requires elevated biosecurity, including prevention of assisted rodent arrival via watercraft, aircraft and animals such as birds. Cattle egrets (Bubulcus ibis) are widespread, and often fly several kilometres daily to roost and forage. They frequently swallow insects and vertebrates (including rodents) whole, and some regurgitate prey. Cattle egrets have been regularly observed flying between the Hawaiian Islands of Ni’ihau (where non-native mice and rats are established) and Lehua (where one species of non-native rat is established and was targeted during a recent eradication attempt). Aims The objectives were to identify the species of rodent that cattle egrets regurgitate following transport between Ni’ihau and Lehua islands, and to determine if any of the rodent individuals regurgitated were alive once deposited onto Lehua Island following 1.1-km oversea flights. Methods Eighty-five individual rodent carcasses (regurgitated by cattle egrets) were collected, preserved and identified to species using morphological characteristics and DNA sequencing. Key results All rodents regurgitated by cattle egrets were dead upon collection on Lehua Island. Although the Pacific rat (Rattus exulans) is the only rodent species on Lehua Island, and field staff suspected the regurgitated rodents were R. exulans, all 85 carcasses were identified as house mice (Mus musculus). Conclusions This is the first evidence (that the authors know of) showing movement of rodent carcasses, via cattle egrets, between islands. Implications Cattle egrets that deposit rodent carcasses onto rodent-free islands, or segments of islands, may confuse land managers and biosecurity professionals who are unaware of this phenomenon. House mice did not survive cattle egret ingestion, >1-km flight and regurgitation; therefore it is unlikely that live rodents would be introduced to rodent-free areas via cattle egrets.
Lower socioeconomic status and the acceleration of aging: An outcome-wide analysis
Authors: Steptoe Andrew , Zaninotto Paola
Published: June 2020

Significance

Lower socioeconomic status (SES) is a determinant of many of the health problems that emerge at older ages. The extent to which lower SES is associated with faster decline in age-related functions and phenotypes independently of health conditions is less clear. This study demonstrates that lower SES (defined by wealth) is related to accelerated decline over 6 to 8 y in 16 outcomes from physical, sensory, physiological, cognitive, emotional, and social domains, independently of diagnosed health conditions, self-rated health, education, and other factors. It provides evidence for the pervasive role of social circumstances on core aging processes and suggests that less affluent sectors of society age more rapidly than more privileged groups.
Wild hummingbirds discriminate nonspectral colors
Authors: Stoddard Mary Caswell , Eyster Harold N. , Hogan Benedict G. , Morris Dylan H. , Soucy Edward R. , Inouye David W.
Published: June 2020

Many animals have the potential to discriminate nonspectral colors. For humans, purple is the clearest example of a nonspectral color. It is perceived when two color cone types in the retina (blue and red) with nonadjacent spectral sensitivity curves are predominantly stimulated. Purple is considered nonspectral because no monochromatic light (such as from a rainbow) can evoke this simultaneous stimulation. Except in primates and bees, few behavioral experiments have directly examined nonspectral color discrimination, and little is known about nonspectral color perception in animals with more than three types of color photoreceptors. Birds have four color cone types (compared to three in humans) and might perceive additional nonspectral colors such as UV+red and UV+green. Can birds discriminate nonspectral colors, and are these colors behaviorally and ecologically relevant? Here, using comprehensive behavioral experiments, we show that wild hummingbirds can discriminate a variety of nonspectral colors. We also show that hummingbirds, relative to humans, likely perceive a greater proportion of natural colors as nonspectral. Our analysis of plumage and plant spectra reveals many colors that would be perceived as nonspectral by birds but not by humans: Birds’ extra cone type allows them not just to see UV light but also to discriminate additional nonspectral colors. Our results support the idea that birds can distinguish colors throughout tetrachromatic color space and indicate that nonspectral color perception is vital for signaling and foraging. Since tetrachromacy appears to have evolved early in vertebrates, this capacity for rich nonspectral color perception is likely widespread.
The AAA+ ATPase Msp1 is a processive protein translocase with robust unfoldase activity
Authors: Castanzo Dominic T. , LaFrance Benjamin , Martin Andreas
Published: June 2020

Significance

The AAA+ ATPase Msp1 has previously been shown to function in the quality control of tail-anchored proteins at the mitochondrial and peroxisomal membranes, yet its detailed mechanisms of substrate processing have remained unknown. Using scaffolds to stabilize the functional hexamer of Msp1 ATPase domains and various model proteins derived from Msp1’s endogenous substrate Pex15, we show that Msp1 is a promiscuous protein translocase that mechanically unfolds and pulls its substrates through the central pore of the ATPase hexamer in an N-to-C or C-to-N terminal direction. The peroxisomal protein Pex3 modulates Msp1’s activity at the peroxisome by directly interacting with the AAA+ hexamer and inhibiting substrate threading.
Abundant expression of maternal siRNAs is a conserved feature of seed development
Authors: Grover Jeffrey W. , Burgess Diane , Kendall Timmy , Baten Abdul , Pokhrel Suresh , King Graham J. , Meyers Blake C. , Freeling Michael , Mosher Rebecca A.
Published: June 2020

Small RNAs are abundant in plant reproductive tissues, especially 24-nucleotide (nt) small interfering RNAs (siRNAs). Most 24-nt siRNAs are dependent on RNA Pol IV and RNA-DEPENDENT RNA POLYMERASE 2 (RDR2) and establish DNA methylation at thousands of genomic loci in a process called RNA-directed DNA methylation (RdDM). In
Brassica rapa
, RdDM is required in the maternal sporophyte for successful seed development. Here, we demonstrate that a small number of siRNA loci account for over 90% of siRNA expression during
B. rapa
seed development. These loci exhibit unique characteristics with regard to their copy number and association with genomic features, but they resemble canonical 24-nt siRNA loci in their dependence on RNA Pol IV/RDR2 and role in RdDM. These loci are expressed in ovules before fertilization and in the seed coat, embryo, and endosperm following fertilization. We observed a similar pattern of 24-nt siRNA expression in diverse angiosperms despite rapid sequence evolution at siren loci. In the endosperm, siren siRNAs show a marked maternal bias, and siren expression in maternal sporophytic tissues is required for siren siRNA accumulation. Together, these results demonstrate that seed development occurs under the influence of abundant maternal siRNAs that might be transported to, and function in, filial tissues.
Biologically inspired flexible photonic films for efficient passive radiative cooling
Authors: Zhang Haiwen , Ly Kally C. S. , Liu Xianghui , Chen Zhihan , Yan Max , Wu Zilong , Wang Xin , Zheng Yuebing , Zhou Han , Fan Tongxiang
Published: June 2020

Significance

Some biological creatures have astonishing photonic structures to exhibit a thermal regulation ability. Taking inspiration from the brilliantly golden longicorn beetles, we demonstrate a bioinspired design of flexible hybrid photonic films for achieving efficient passive radiative cooling. Resonant polar dielectric microsphere particles were introduced into polydimethylsiloxane with photonic architectures to enhance the visible to near-infrared reflectivity and the midinfrared emissivity, enabling considerable subambient temperature drops under direct sunlight. This work paves the way toward radiative cooling technology based on photonic radiators with high performance and large-scale production, showing great potential for energy savings and efficient power generation.
EYES ABSENT and TIMELESS integrate photoperiodic and temperature cues to regulate seasonal physiology in
Drosophila
Authors: Abrieux Antoine , Xue Yongbo , Cai Yao , Lewald Kyle M. , Nguyen Hoang Nhu , Zhang Yong , Chiu Joanna C.
Published: June 2020

Significance

Extracting information regarding calendar time from seasonal changes in photoperiod and temperature is critical for organisms to maintain annual cycles in physiology and behavior. Here we found that, in flies, EYES ABSENT (EYA) protein acts as a seasonal sensor by adjusting its abundance and phase in response to changes in photoperiod and temperature. We show that the manipulation of EYA levels is sufficient to impair the ability of female
Drosophila
to regulate seasonal variation in reproductive dormancy. Finally, our results suggest an important role for the circadian clock protein TIMELESS (TIM) in modulating EYA level through its ability to measure night length, linking the circadian clock to seasonal timing.
Dynamic measurement of cytosolic pH and [NO
3
−
] uncovers the role of the vacuolar transporter AtCLCa in cytosolic pH homeostasis
Authors: Demes Elsa , Besse Laetitia , Cubero-Font Paloma , Satiat-Jeunemaitre Béatrice , Thomine Sébastien , De Angeli Alexis
Published: June 2020

Significance

Intracellular transporters are key actors in cell biological processes. Their disruption causes major physiological defects. Intracellular ion transporters are usually thought to control luminal conditions in organelles; meanwhile, their potential action on cytosolic ion homeostasis is still a black box. The case of a plant Chloride Channel (CLC) is used as a model to uncover the missing link between the regulation of conditions inside the vacuole and inside the cytosol. The development of an original live imaging workflow to simultaneously measure pH and anion dynamics in the cytosol reveals the importance of an
Arabidopsis thaliana
CLC, AtCLCa, in cytosolic pH homeostasis. Our data highlight an unsuspected function of endomembrane transporters in the regulation of cytosolic pH.
A corpus approach to the history of Russian po
delimitatives
Authors: Eckhoff Hanne Martine
Published: June 2020

This paper illustrates how enriched diachronic treebank data can shed new light
on an old and vexed topic, even when that topic is primarily morphological and
semantic in nature rather than syntactic. The topic is the rise of the Russian
po delimitatives, a change seen as crucial in most accounts
of the history of Russian aspect, since it represents a major step in
generalising the derivational aspect system. Earlier accounts concur that the
po delimitatives spread fairly recently, too recently for
the development to be connected to the loss of the aorist tense, which also had
delimitative readings with atelic verbs. Using treebank data from the Tromsø Old
Russian and Old Church Slavonic Treebank, enriched with tags for derivational
morphology and semantics, I show that the po delimitatives were
not marginal even in the earliest Slavic sources, either in terms of frequency
or semantics, and that they first complemented and then competed with the
delimitative aorists. It can thus be claimed that the exotic po
delimitatives grew organically out of the old Indo-European inflectional aspect
system.
The internet and social media as a theme and channel of humor
Authors: Piskorska Agnieszka
Published: June 2020

This paper deploys the tools of relevance theory to establish a common pragmatic mechanism operating in humorous texts
(stand-up comedy, jokes, sketches) themed on the omnipresence of the Internet and social media in human life. It is postulated that this
mechanism resides in incongruity between shared cultural assumptions expressing high esteem for rational actions and informative
communication, and private assumptions endorsed by internet application users, who find phatic communication pleasurable. It is claimed that
incongruity so understood is not a central but additional pragmatic mechanism in various humorous genres, and it tends not to be resolved,
as tension between these two sets of assumptions lingers on.
On the order of processing of humorous tweets with visual and verbal elements
Authors: Simarro Vázquez María , El Khatib Nabiha , Hamrick Phillip , Attardo Salvatore
Published: June 2020

In this paper we examine the order of processing of multimodal tweets (text + image). Using an eye tracker, we collected a
sample of 36 participants reading 25 humorous tweets. Our conclusions show that the processing of multimodal humorous tweets is in line with
the processing of other multimodal texts. The participants were significantly more likely to start from the image, followed by the caption.
Other elements, such as the tweet’s “author” (the user name) or elements outside the tweet’s frame, attracted significantly less and later
attention. The participants spent significantly more time gazing at the caption, before moving on to another area. The longer the
participants spent looking at the tweet, the less predictable their gaze direction became.
Sophocarpine ameliorates cardiac hypertrophy through activation of autophagic responses
Authors: Lin Yue-Bao , Huang Dong-Jian , Huang Huan-Liang , Chen De-Xiong , Huang Jiong-Hua
Published: June 2020

Mounting evidences indicate that autophagy is an essential homeostatic mechanism to maintain the global cardiac structure function. Sophocarpine (SOP), a major bioactive compound derived from the natural plant Sophora flavescens. However, the role of SOP in cardiac hypertrophy remain to be fully elucidated. In the present study, we tested the hypothesis that SOP protects against Ang II–induced cardiac hypertrophy by mediating the regulation of autophagy. The results demonstrated that SOP attenuated the Ang II–induced cardiac hypertrophy, as assessed by measurements of echocardiography parameters, the ratios of heart weight/body weight and left ventricle weight/body weight, histopathological staining, cross-sectional cardiomyocyte area, and the expression levels of cardiac hypertrophic markers. The anti-hypertrophic effect of SOP was mediated by activating autophagy-related pathway, as revealed by reversal of the increased autophagy marker protein expression. These findings reveal a novel mechanism of SOP attenuating cardiac hypertrophy via activating autophagy-related signaling pathways.
Development of a Fluence Generating Programme for Patient-Specific Quality Assurance and Calibration of an Amorphous Silicon EPID
Authors: Yeap C F , Jong W L , Ung N M
Published: June 2020

Patient-specific quality assurance (QA) is an essential part of intensity-modulated radiotherapy (IMRT) and volumetric arc therapy (VMAT) treatments. This study aims to develop a Patient-specific QA system through the development of a fluence generating programme and utilization of amorphous silicon (aSi) electronic portal imaging device (EPID). The EPID was investigated on the dependency of dose rate, uniformity of detector sensitivity and output factor. A fluence generating programme was written using MATLAB. Five simple dynamic arc plans and one patient VMAT plan were created using the Monaco treatment planning system which were used in the programme to generate fluence maps. The accuracy of the programme was evaluated by performing gamma analysis between the generated and measured fluence. EPID signal was found to be linearly proportional to dose (1-1000 MU) and independent of dose rate. The mean uniformity ratio was 1.07 ± 0.04%. The measured fluence maps were corrected for uniformity before gamma analysis. Output factor and dose deposition were taken into account in the process. The average result of the gamma analysis passed the 95% threshold. A fluence generating programme was developed, serving as the foundation of the Patient-specific QA system using aSi EPID for IMRT/VMAT delivery in this centre.
The Effect of Lung Tumors Target Movement on Neutron Dose
Authors: Nistiyanti I , Putranto A M Y , Nugroho F , Nainggolan A , Fadli M , Liura S , Tursinah R , Pawiro S A
Published: June 2020

In radiation therapy, high energy photon above 10 MV could produce neutron. Small dose of neutron can provide biological effect in patient’s body in a long term with high risk. The study aims to recognize the distribution of neutron dose for the moving and non-moving target of tumor. Neutron dose was measured by using TLD 600(LiF: Mg,Ti) and TLD 100 (LiF: Mg.Ti) in tumor target and spinal cord as organs at risk (OAR). The study used In-House Dynamic Thorax phantom movable in translation and rotation within the amplitude of 5, 10, and 15 mm. Phantom was irradiated by the techniques of 3DCRT, IMRT, and VMAT using 15 MV. The result by calculation using thermal calibration factor shows that the average of distribution the neutron dose of tumor target was increase caused by the amplitude movements. On the technique 3DCRT, the dose of neutron increased by 9%, 34%, 68% respectively on the amplitude movements of 5, 10, and 15 mm, respectively, whereas increased by 2%, 25%, 70% respectively on the amplitude movements for IMRT techniques. Moreover, on the VMAT technique, it also increased by 3%, 8%, 54% respectively on the amplitude movements. The result of study shows that the distribution of neutron dose of tumor target and spinal cord increased with the amplitude increment and VMAT technique provided the highest dose of neutron compared to other techniques of irradiation.
Microstructure and dosimetric characterisation of delaminated film dosimeter under 12 MeV electron beam
Authors: Tagiling N , Khairil Anuar MA , Ab Rashid R , Dollah N , Rahman WN
Published: June 2020

Delaminated GAFCHROMIC™ EBT3 radiochromic films (RCFs) are specialised dosimeters that are gaining attention due to its many prospective advantages but are not commercially available. The purpose of this study is to fabricate the delaminated EBT3 RCFs, microscopically examine the structural response of the active layer (LiPCDA), and evaluate its dose-response in electron beam radiotherapy. The delaminated EBT3 RCFs were first made by carefully removing one of the two 125 μm polyester substrates using precision forceps. Next, the films were irradiated using a 12 MeV electron beam under full equilibrium conditions. Microstructure analysis via scanning electron microscope (SEM) was employed to look into the effects of radiation polymerisation on the LiPCDA crystals at 3000× magnification. To characterise the dose-response, the delaminated EBT3 RCFs’ optical density were analysed in Red-channel across a dose range of up to 5 Gy. The resulting calibration curve was then compared with the standard EBT3 RCFs’ curve for performance evaluation. Images from SEM revealed that the irradiated EBT3 RCF possesses a higher density of longer LiPCDA crystals (mode: ∼8.00 μm) compared to the non-irradiated EBT3 RCF (mode: ∼4.00 μm). The delaminated EBT3 RCFs, nonetheless, was found to produce a combined standard uncertainty of 6.62 %, which is inferior to its standard counterpart (3.62 %) and also the radiotherapy’s tolerance level (± 5 %). In sum, this study had successfully demonstrated the effects of radiation polymerisation on the active layer. However, the delamination process introduced a significant amount of uncertainty towards the dose-response. More efforts into delamination techniques and better dosimetry analysis are required to improve its usability in radiotherapy.
Comparison of Dose Volume Histogram (DVH) of Simulated Object Calculated by Analytically and Treatment Planning System (TPS): Preliminary Study
Authors: Fitriyani  , Saputra A , Prajitno P , Soejoko D S
Published: June 2020

TPS is the key to the success of external radiotherapy medication, which directly affects the quality of treatment planning and accuracy of dose calculation within the plan. The output of TPS’s plan result is in form of DVH curve. DVH is the reference for dose dispersion on the target or healthy organ. Within this research, DVH result from the TPS and DVH result from analytical calculation were compared. The DVH comparison was started by creating a simulation object in form of virtual phantom using Matlab program in various geometrical shapes, which were sphere, cube, and cylinder. The planning on simulation object was conducted using TPS Eclipse. From the result of the plan using TPS Eclipse and analytical measurement, it can be concluded that the highest value difference was on the sphere object simulation. While for the Dmax and Dmin value comparison, the highest difference was in Dmin with the highest discrepancy. This was caused by the voxel size on each measurement. Besides, the dose value of interpolation and voxel determination on the surface of the geometrical simulation object also affected the value of analytical measurement, so it resulted in the higher value compared to the calculation result on each TPS.
The Characteristic of Profile and Depth Dose of Neutron Clinac iX 15 MV
Authors: Suryaningsih S. , Nainggolan A. , Fadli M. , Liura S. , Fendinugroho  , Tursinah R. , Pawiro S. A.
Published: June 2020

Several previous studies described that radiation neutrons are produced by 10 MV X-ray beams operated linac. This study was performed to exercise the characteristic of profile and neutron depth dose for 15 MV X-ray beams and also to evaluate the contribution of neutron dose to the patient. The experiment used Linac iX with 15 MV X-ray beam, TLD-100, TLD-600, and phantom. The phantom was designed to evaluate the dose profile at cross-plane and diagonal axis. TLDs were calibrated separately by gamma and neutron sources. Gamma calibration was carried out using 137Cs source whereas neutron calibration was done using 252Cf source at BATAN Facility. Neutron dose equivalents were calculated on cross-plane and diagonal axis in 10 cm × 10 cm fields at 15 positions from the central axis, on the phantom surface and depths of 2 cm, 3 cm, and 15 cm. The percentage maximum neutron dose equivalent distributions were obtained around of 3 cm depth for cross-plane and diagonal axis. Furthermore, the dose profile of neutron at different depths and off-axis position are not symmetrical. Neutron dose in out-of-field had no significant response compared to the in-field. The relative neutron dose in out-of-field is 27% and 24% normalized to the maximum neutron dose at each depth on cross-plane and diagonal axis respectively.
Study of Longitudinal Relaxation Time Multi Echo Multi Planar (T1 MEMP) and Diffusion Weighted Imaging (DWI) on Magnetic Resonance Imaging (MRI) Image
Authors: Alam D Y , Milani  , Rauf N , Samad B A
Published: June 2020

Magnetic Resonance Imaging (MRI) is an imaging technique for the human body cross-section, which utilizes electromagnetic radiations in the form of radio frequency. The MRI imaging technique is relatively complex, since the resulted images depend on many parameters, including Time Repetition (TR) and Time Echo (TE). This research is aimed to analyze the selection of TR and TE parameters, as well as to analyze the differences of signal intensity on White Matter (WM) tissue, Gray Matter (GM) tissue, and Cerebrospinal Fluid (CSF) of T1 MEMP and DWI images in the human brain. The obtained results showed that T1 MEMP images had short TR value (400–500 ms) and short TE value (13 ms), while DWI images had a b-value = 1,000 s/mm2 with long TR value (7,000 ms) and long TE value (80–90 ms). The resulted signal intensity on WM tissue, GM tissue, and CSF was measured based on gray value distribution using RadiAnt DICOM Viewer version 2.2.9.10728 (64 bit) and ENVI version 4.5 software. The results showed that the average of gray value distribution on T1 MEMP images were 46.5–66.5 for GM tissue, 67.5–94 for WM tissue, and 18.9–45.5 for CSF, while the average of gray value distribution on DWI images were 178–255 for GM tissue, 92.1–177 for WM tissue, and 31.5–91.1 for CSF. Hence, the WM tissue appeared clearer by using T1 MEMP images and the GM tissue appeared clearer by using DWI images.
The comparison between synthetic mammography reconstructed from digital breast tomosynthesis and full-field digital mammograms in the detection and assessment of Calcification
Authors: Songsaeng C , Woodtichartpreecha P , Rohitopakarn P
Published: June 2020

To compare the observer agreement of calcification detection and assessment on synthetic mammography reconstructed to full-field digital mammograms. This retrospective study included 68 patients who undertaken screening mammogram. For each patient, FFDM and DBT were performed at Songklanakarind Hospital. Two-experienced radiologists retrospectively reviewed SM and FFDM, in separate sessions, to detect micro-calcifications and provide a BIRADS assessment. The kappa of SM and FFDM in radiologist1 in type of calcification was 0.49 (0.29-0.68), type of benign was 0.49 (0.29-0.49), type of suspicious was 0.17 (-0.06-0.42). The kappa of SM and FFDM in radiologist2 in type of calcification was 0.74 (0.61-0.87), type of benign was 0.39 (0.2-0.57), type of suspicious was 0.26 (0.11-0.4). The kappa of radiologist1 and radiologist2 of FFDM in type of calcification was 0.49 (0.29-0.68), type of benign was 0.39 (0.2-0.58), type of suspicious was 0.42 (0.24-0.59). The kappa of radiologist1 and radiologist2 of SM in type of calcification was 0.82 (0.72-0.93), type of benign was 0.49 (0.32-0.66), type of suspicious was 0.14 (0.02-0.31). In conclusion, the SM performances are similar as FFDM for detection type of calcification in diagnostic mammography screening whether the radiologist should concern about the image contrast and image reconstruction of SM.
The Effect of silicone rubber-lead (SR-Pb) as an additional filter on radiation dose and image quality in computed radiography (CR)
Authors: Zahroh F , Anam C , Sutanto H , Irdawati Y , Hidayanto E , Arifin Z , Indrayanti U
Published: June 2020

This study aims to determine the validity of the Silicone Rubber-Lead (SR-Pb) as an additional filter on the computed radiography (CR) using the tube voltage of 70 kVp and current-time of 6.3 mAs with a Pb percentage of 5 wt%. In addition, the thickness variations of the SR-Pb were 2, 4mm, 6mm, 8mm, and 10 mm, were compared to the Aluminum (Al) filter, of 0.5 mm, 1.0 mm and 1.5 mm. The effect of both SR-Pb and Al filters on radiation dose and image quality was studied. The radiation dose was measured using the Piranha detector, while the image quality was quantified using the signal to noise ratio (SNR) and the contrast to noise ratio (CNR) from images of the CDR TOR phantom. It was found that the dose decreased with an increase in the thickness of SR-Pb filter. At 77% and 53%, the thickness increased to 10 mm and 6 mm, respectively, which is equivalent to a 1.5 mm Al filter. The result showed that when CNR decreases, SNR increases with a rise in thickness values of SR-Pb filter. The decrease in CNR value at 6 mm SR-Pb filter was greater than 1.5 mm Al which is 45.3% and 11.04%, respectively. In addition, the use of SR-Pb filter led to an increase in SNR value by 45.9%, while the 1.5 mm Al filter increased SNR value of about 47.5% In conclusion, the SR-Pb filter has the potential to be used as an alternative additional filter for the CR examination.
T2 Quantification of Agarose with Contrast Agent in Magnetic Resonance Imaging
Authors: Dwihapsari Y , Asdiantoro E , Maulidiyah N
Published: June 2020

Spin-spin relaxation time or T2 is an important parameter in Magnetic Resonance Imaging (MRI) which provides information on molecular structure inside tissues, properties of human tissues and metabolites inside human body. It also contributes to clinical study by providing more information on pathological properties and delineation between healthy and malignant tissues in brain pathologies and identification of tissue abnormalities. In this study, T2 measurement was performed by acquiring T2 images of agarose hydrogel. T2-weighted imaging sequence was used with variation of agarose concentration, echo-time and repetition time. The signal intensities of samples were acquired and fitted to echo-time to obtain T2-value. In addition, contrast agent of CuSO4 was mixed with agarose solution and the similar T2 measurement was performed with variation concentration of agarose and CuSO4. Although some limitations were found during T2 measurement due to acquisition and instrumental setting, T2 quantification could provide more information about properties inside samples. The quantification could also be used for measurement of the effectiveness of contrast agent for increasing image contrast in MRI scanning.
The establishment of the national dose reference level (DRL) for head-CT examination in Indonesia
Authors: Budi Verinda Sera , Anam Choirul , Yoyo Wardaya Asep , Rusmanto  , Bagus Gede Putra Pratama Ida
Published: June 2020

The dose reference level (DRL) is one of the tools for dose optimization in every radiological practice. However, Indonesia does not have a national DRL for CT which can be adopted nationally to date. This research was aimed to develop the national DRL for the head CT examination. There were 636 survey booklets with 20.211 patient data. All data then were classified into contrast and non-contrast parameters. Outliers data were removed from the data list by z-score. MATLAB R2017b was used to determine minimum, maximum, the first, second and third quartile values. The third quartile of data was identified as the DRL value. It was found that national DRLs in terms of CTDIvol, DLP, and effective dose were 60 mGy, 1,811 mGy-cm, and 3.8 mSv for the contrast parameter, and 61 mGy, 1,350 mGy-cm, and 2.8 mSv for the non-contrast parameter. National DRL values for males and females show the same value when stated in CTDIvol. Meanwhile, the national DRL value for males is greater than that for females when expressed in DLP and effective dose. These results are consistent with the differences in head size that is relatively larger in males than in females.
The Impact of Mg Concentration, Microwave Irradiation Time, and Sintering on Magnesium-Hydroxyapatite Synthesis
Authors: Siregar J A , Nurlely  , Sari Y W
Published: June 2020

Hydroxyapatite synthesis is an inorganic compound that makes up the hard tissues of the human body such as bones. This study aims to substitute Magnesium (Mg) ions, which have an important role in the structure and function of the human body, in Calcium (Ca) ions from Hydroxyapatite. MgHA crystals are synthesized by mixing a solution of diammonium hydrogen phosphate and magnesium hydroxide into a calcium hydroxide solution which is then irradiated with microwaves, with variations in the concentration of Mg and irradiation time. From the XRD results show that along with the increase in Mg concentration and irradiation time the lattice parameter values a and c are reduced by 0.03 in lattice a and 0.01 in lattice c. The increase in irradiation time is proportional to the increase in crystal size (L) and crystallinity index (CI). At t = 35 it is found L = 19.08 nm and CI = 0.14. The increase in Mg concentration is proportional to the increase in crystal size and crystallinity index, the increase in Mg concentration above 0.6 M shows the presence of saturation in the binding process of Mg in the apatite structure. The sintering process at 900ºC increases the crystal size value from 19.08 nm to 52.09 nm and the crystallinity index from 0.14 to 2.97. Morphology of MgHA produces rod-shaped particles with agglomeration caused by a large amount of Mg content in apatite.
Bioenergy Alteration in White Rats (Rattus norvegicus) due to the Acupuncture Needle Stimulation
Authors: Rahmawati T , Fitriyah N , Astuti S D , Septriana M , Suhariningsih
Published: June 2020

The research have been conducted to determine the bioenergy alteration in white rat (Rattus Norvegicus) due to needle stimulation in acupuncture point. Twenty eight male white rat were divided randomly to 4 groups. Group 1 was untreated (control). Group 2 was treated by acupuncture with 15 Hz frequency, 10 minutes, for 5 days at Zusanli (SP 36) point. Group 3 was treated by acupuncture with 15 Hz frequency, 10 minutes, for 5 days at combination Zusanli (SP 36) points – Sanyinjiao (SP 6) point. Group 4 was treated by ephedrin’s oral consumtion for 5 days in 3 mg/kg weight and the parameter that was used is a maximum travel time of the white rat in the tredmill’s trajectory until it reaches the point of exhaustion before and after treatment. The addition of travel time is comparable with the addition of bioenergy, so bioenergy changes in group 2 and 3 can be calculated. The result of multiple comparative analysis with the Least Significant Difference (LSD) of the control group againts ST 36 group indicate a significant difference (p=0,006), control group againts group combination ST 36 – SP 6 indicate a significant difference (p=0,023) and control group againts ephedrin’s oral consumption group not indicate a significant difference (p=0,772). Electroacupuncture at Zusanli (SP 36) point and combination Zusanli (SP 36) points – Sanyinjiao (SP 6) point can affect changes of bioenergy.