25 research outputs found

    Bayesian model calibration for diblock copolymer thin film self-assembly using power spectrum of microscopy data

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    Identifying parameters of computational models from experimental data, or model calibration, is fundamental for assessing and improving the predictability and reliability of computer simulations. In this work, we propose a method for Bayesian calibration of models that predict morphological patterns of diblock copolymer (Di-BCP) thin film self-assembly while accounting for various sources of uncertainties in pattern formation and data acquisition. This method extracts the azimuthally-averaged power spectrum (AAPS) of the top-down microscopy characterization of Di-BCP thin film patterns as summary statistics for Bayesian inference of model parameters via the pseudo-marginal method. We derive the analytical and approximate form of a conditional likelihood for the AAPS of image data. We demonstrate that AAPS-based image data reduction retains the mutual information, particularly on important length scales, between image data and model parameters while being relatively agnostic to the aleatoric uncertainties associated with the random long-range disorder of Di-BCP patterns. Additionally, we propose a phase-informed prior distribution for Bayesian model calibration. Furthermore, reducing image data to AAPS enables us to efficiently build surrogate models to accelerate the proposed Bayesian model calibration procedure. We present the formulation and training of two multi-layer perceptrons for approximating the parameter-to-spectrum map, which enables fast integrated likelihood evaluations. We validate the proposed Bayesian model calibration method through numerical examples, for which the neural network surrogate delivers a fivefold reduction of the number of model simulations performed for a single calibration task

    Carbon-Chain Molecules in Molecular Outflows and Lupus I Region--New Producing Region and New Forming Mechanism

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    Using the new equipment of the Shanghai Tian Ma Radio Telescope, we have searched for carbon-chain molecules (CCMs) towards five outflow sources and six Lupus I starless dust cores, including one region known to be characterized by warm carbon-chain chemistry (WCCC), Lupus I-1 (IRAS 15398-3359), and one TMC-1 like cloud, Lupus I-6 (Lupus-1A). Lines of HC3N J=2-1, HC5N J=6-5, HC7N J=14-13, 15-14, 16-15 and C3S J=3-2 were detected in all the targets except in the outflow source L1660 and the starless dust core Lupus I-3/4. The column densities of nitrogen-bearing species range from 1012^{12} to 1014^{14} cm2^{-2} and those of C3_3S are about 1012^{12} cm2^{-2}. Two outflow sources, I20582+7724 and L1221, could be identified as new carbon-chain--producing regions. Four of the Lupus I dust cores are newly identified as early quiescent and dark carbon-chain--producing regions similar to Lup I-6, which together with the WCCC source, Lup I-1, indicate that carbon-chain-producing regions are popular in Lupus I which can be regard as a Taurus like molecular cloud complex in our Galaxy. The column densities of C3S are larger than those of HC7N in the three outflow sources I20582, L1221 and L1251A. Shocked carbon-chain chemistry (SCCC) is proposed to explain the abnormal high abundances of C3S compared with those of nitrogen-bearing CCMs. Gas-grain chemical models support the idea that shocks can fuel the environment of those sources with enough S+S^+ thus driving the generation of S-bearing CCMs.Comment: 7 figures, 8 tables, accepted by MNRA

    Preparation and Characterization of Biocompatible Iron/Zirconium/Polydopamine/Carboxymethyl Chitosan Hydrogel with Fenton Catalytic Properties and Photothermal Efficacy

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    In recent years, multifunctional hydrogel nanoplatforms for the synergistic treatment of tumors have received a great deal of attention. Here, we prepared an iron/zirconium/polydopamine/carboxymethyl chitosan hydrogel with Fenton and photothermal effects, promising for future use in the field of synergistic therapy and prevention of tumor recurrence. The iron (Fe)–zirconium (Zr)@ polydopamine (PDA) nanoparticles were synthesized by a simple one-pot hydrothermal method using iron (III) chloride hexahydrate (FeCl3•6H2O), zirconium tetrachloride (ZrCl4), and dopamine, followed by activation of the carboxyl group of carboxymethyl chitosan (CMCS) using 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC)/N(4)-hydroxycytidine (NHS). Finally, the Fe–Zr@PDA nanoparticles and the activated CMCS were mixed to form a hydrogel. On the one side, Fe ions can use hydrogen peroxide (H2O2) which is rich in the tumor microenvironment (TME) to produce toxic hydroxyl radicals (•OH) and kill tumor cells, and Zr can also enhance the Fenton effect; on the other side, the excellent photothermal conversion efficiency of the incorporated PDA is used to kill tumor cells under the irradiation of near-infrared light. The ability of Fe–Zr@PDA@CMCS hydrogel to produce •OH and the ability of photothermal conversion were verified in vitro, and swelling and degradation experiments confirmed the effective release and good degradation of this hydrogel in an acidic environment. The multifunctional hydrogel is biologically safe at both cellular and animal levels. Therefore, this hydrogel has a wide range of applications in the synergistic treatment of tumors and the prevention of recurrence

    Morphological Analysis of Fractures of the Proximal Humerus by the Fracture Mapping Technique

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    Objective Fractures of different parts of the proximal humerus may lead to different postoperative functional deficits, but there are few studies on the morphology and related functions of the proximal humerus. The purpose of this study was to analyze the fracture pattern of the proximal humerus by the three‐dimensional (3‐D) fracture mapping technique and to further evaluate its clinical utility. Methods Patients with proximal humeral fractures admitted to Pudong Hospital, Fudan University, from January 2018 to December 2020, were analyzed. Three surgeons divided the fractures into groups according to the 3‐D CT imaging technique and mapped the fractures on a 3‐D template according to the fracture line of each fracture. Finally, the humeral head inversion angle and the functional score were recorded in different fracture types. Results A total of 312 cases of humeral fractures were included. Among them, there were 90 patients (28.8%) in the simple greater tuberosity + lesser tuberosity + medial cortex group, with typical fracture features of surgical neck fractures of the humerus + greater tuberosity fractures. Eighty‐seven patients (27.9%) in the greater tuberosity + isolated fragment lesser tuberosity + medial cortex group had typical “four‐part fractures.” There were 45 patients (14.4%) in the greater tuberosity + lesser tuberosity + medial isolated fragment group. Moreover, more patients in this group had medial comminution due to varus displacement of the femoral head. There were 66 patients (21.1%) in the isolated greater tuberosity group, 21 patients (6.7%) in the greater tuberosity + lesser tuberosity group, and three patients (1.0%) in the greater tuberosity + medial cortex group. In addition, the humeral head inversion angle and other statistical differences were observed in the greater tuberosity + lesser tuberosity + medial isolated fragment group. Conclusions This morphological study helps to further identify the characteristics of proximal humerus fracture patterns, which may be closely related to different clinical outcomes. Further relevant studies are needed to verify the reliability of their clinical application and the potential value in surgical planning and postoperative functional rehabilitation

    Does isolated greater trochanter implication affect hip abducent strength and functions in intertrochanteric fracture?

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    Abstract Background A fracture in the isolated greater trochanter is an infrequent type of femoral intertrochanteric fracture. The gluteus medius and gluteus minimus are abducent muscle groups with attachments located on the greater trochanter. Thus, a fracture of the greater trochanter could cause avulsion injury of these attachment points and eventually affect the abducent function of the hip joint and cause chronic pain. Despite these prospects, the impact of a greater trochanter fracture on abducent strength and hip joint function have yet to be investigated. Methods Patients who were diagnosed with an isolated greater trochanter fracture (via computed tomography scan and X-ray) and underwent conservative treatment from June 2013 to October 2016 were included in the present study. Magnetic resonance imaging (MRI) was used to verify the morbidity of recessive fractures. Patients’ Harris Hip Scores were determined at 3 months, 6 months, and 12 months and the abducent strength and range of motion of the hip joint on the injured side were analyzed and compared to those on the healthy side. Result Among 32 patients, there were 7 individuals diagnosed with isolated greater trochanter fractures by MRI, and 25 individuals whose fractures were found to have extended into the intertrochanteric region, wherein the recessive intertrochanteric region fractures had no relationship with patients’ age, gender, or weight. After 12 months of conservative treatment, 7 patients still complained of pain in the hip joint. The average Harris Hip Score was 87.84 ± 4.83, and the abducent range of the hip joint on the injured side (42.02 ± 13.93°) was not significantly different from that of the healthy side (46.24 ± 7.93°). The abducent strength of the hip joint of the injured side was 121.32 ± 41.06 N which was significantly lower than that of healthy side (137.44 ± 42.21 N). Conclusion Results from this investigation suggest that an isolated greater trochanter fracture attenuates the abducent strength of the hip joint, which may be related to injuries of the ligaments and muscles around the greater trochanter. The surgical skills and methods of addressing isolated greater trochanter fractures merit further investigation

    PENERAPAN METODE BERMAIN AKTIF MENGGUNAKAN STIK ANGKA UNTUK MENINGKATKAN KETELITIAN DAN KEMAMPUAN MENGENAL BILANGAN ANAK USIA DINI (Studi Pada Kelompok B Paud Negeri Pembina Lais Kabupaten Bengkulu Utara)

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    Tujuan penelitian ini untuk meningkatkan ketelitian dan mengenal bilangan anak usia dini melalui penerapan metode bermain aktif menggunakan stik angka. Metode penelitian ini adalah penelitian kombinasi yang diawali dari Penelitian Tindakan Kelas (PTK) yang dilanjutkan dengan kuasi eksperimen. Adapun Subjek PTK adalah 12 anak kelompok B1, kelas eksperimen adalah 12 anak kelompok B3, kelas kontrol adalah 10 anak kelompok B4. Teknik pengumpulan data yang digunakan adalah observasi terhadap guru dan anak.Teknik analisa data untuk PTK menggunakan rumus nilai rata-rata, untuk melihat peningkatan dan signifikasi digunakan uji-t. Untuk kuasi eksperimen digunakan uji-t dua sampel tidak saling berhubungan. Pengolahan data menggunakan uji-t. Hasil penelitian ini menunjukkan adanya peningkatan ketelitian dan mengenal bilangan anak usia dini melalui penerapan metode bermain aktif menggunakan stik angka , terbukti > (4.312>1.725) begitupun pada kuasi ekperimen tentang kemampuan mengenal bilangan terjadi peningkatan > ( 8.558>1.725). Penelitian ini memberikan saran metode bermain aktif menggunakan stik angka menjadi alternatif meningkatkan ketelitian mengenal bilangan. Kata kunci: Metode Bermain aktif, Stik angka, Ketelitian, Kemampuan Mengenal bilangan, Anak Usia Din

    The Culprit behind the Mass Death of Mangroves: Egrets or <i>Rats</i> (<i>Rattus losea</i>)?

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    Mangroves play a crucial role in maintaining coastal ecological balance. This study focused on the impact of branch-breaking behavior on the mortality of Rhizophora stylosa in the Guangxi Shankou Mangrove Reserve. However, we found mangrove mortality in areas devoid of egret habitation, prompting a reevaluation of our research hypothesis. Further investigation suggested that nesting behavior was the primary cause of mangrove mortality. A comparison of the data from areas with egrets (Egretta garzetta, Ardea intermedia) and lesser rice-field rats (Rattus losea) activity indicated significant mechanical damage caused by rats to mangroves as the main cause of mortality. Additionally, we found that the biological characteristics of R. stylosa, particularly its stunted growth and recovery abilities after branch breaking, were key factors affecting its survival. These findings imply that rat-induced mortality may not occur in other less susceptible mangrove species. The results contradict assumptions regarding the impact of egret behavior and highlight the importance of the biological characteristics of R. stylosa. This offers fresh insights into mangrove conservation and management, emphasizing the need for ongoing observation and hypotheses verification. Future studies should explore the influence of lesser rice-field rats’ activity and the intrinsic characteristics of R. stylosa on the ecosystem’s long-term stability

    A numerical study for dielectric constant profile of aqueous solvent in ionic solution radiated by high-intensity electric pulses

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    In this paper, a mathematical physics model is set up to study dielectric constant profile of aqueous solvent in ionic solution, to revise Brownian dynamics simulation in ionic solution by considering time-variant dielectric constant profile with change in ion positions, and to study the effect of high-intensity electric pulses on the profile. The validation of the model is confirmed with verification calculations. By means of the proposed model, dielectric constant profiles in calcium chloride and sodium chloride solutions and their response to pulses are simulated. Based on numerical results, dielectric constants of aqueous solvent spatially vary instead of being the same value in ionic solutions. And the profiles are variant with time due to ion motion in solutions. From the profiles, overall dielectric constant in calcium chloride solution is lower than that in sodium chloride solution. And overall dielectric constant decreases with increment of solution concentration. In addition, the results show that influence on the profiles depends on solution concentration and field intensity of the pulse. The profile in solutions with low concentration is more vulnerable to the pulse than that with high concentration. And overall dielectric constant decreases dramatically as field intensity increases. Those understandings provide basis for application of pulses in biomedical engineering at the molecular level. Meanwhile, pulse radiation provides a potential way to constrain water molecules at room temperature reflected by significantly reducing dielectric constant, and to lower absorption loss of electromagnetic field in millimeter and far infrared band

    Continual expansion of Spartina alterniflora in the temperate and subtropical coastal zones of China during 1985–2020

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    Biological invasions are considerably altering ecosystem structure and functions, especially in coastal ecosystems that are subject to intensive anthropogenic disturbances. Spartina alterniflora has been recognized as the most serious invasive species in coastal China, which has received considerable attention from the government and the public. There is urgent need to control this invasive species at regional and national scales, but such efforts were impeded by lack of time-series data of Spartina spread. Here, we assessed the pixel- and phenology-based algorithm for mapping Spartina saltmarshes, and applied this algorithm to generate annual Spartina saltmarsh maps (30-m spatial resolution) from 1985 to 2020 by using time series Landsat 5/7/8 images. The resulting maps suggest that Spartina has been expanding since 1990 in coastal China, with three noticeable phases (rapid, moderate, and rapid). Along the latitudinal gradient, Spartina exhibited a longer invasion history and more frequent changes at low latitudes. Although human interventions caused the decline of Spartina in certain areas, rapid natural spread was primarily responsible for its extensive and continual invasion. These results provide insights for efficiently managing this invasive species, enhancing the conservation of coastal wetlands, and promoting the sustainability of coastal wetlands

    Interpretation of the molecular mechanism of the electroporation induced by symmetrical bipolar picosecond pulse trains

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    Picosecond pulse trains (psPTs) are emerging as a new characteristic diagnostic and therapeutic tool in biomedical fields. To specifically determine the stimulus provided to cells, in this article, we use a molecular dynamics (MD) model to show the molecular mechanisms of electroporation induced by symmetrical bipolar psPTs and predict a bipolar cancellation for the studied picosecond pulses. Electric field conditions that do not cause electroporation reveal that the interfacial water molecules continuously flip and redirect as the applied bipolar psPT reverses, and the molecules cannot keep moving in one direction or leave the lipid-water interface. Based on our simulation results, we determine the threshold for electroporation with symmetrical bipolar psPTs. For a fixed electric field intensity, a lower repetition frequency leads to more rapid electroporation. For a fixed repetition frequency, a higher electric field intensity leads to more rapid electroporation. We found that the water dipole relaxation time decreases as the electric field magnitude increases. Additionally, the influences of the symmetrical bipolar psPT intensity and frequency on the pore formation time are presented. Discrete nanoscale pores can form with the applied psPT at terahertz (THz) repetition frequency. When the psPT amplitude increases or the frequency decreases, the number of water bridges will increase. Moreover, for the first time, the molecular mechanism of bipolar cancellation for the studied picosecond pulse is discussed preliminarily. Our results indicate that the influence of the unipolar picosecond pulse on the interfacial water dipoles will accumulate in one direction, but the bipolar picosecond pulse does not cause this effect
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