bluuebunny/crossref_metadata_2025 huggingface dataset:
Identifying the Multi-Scale Influences of Climate Factors on Runoff Changes in a Typical Karst Watershed Using Wavelet Analysis
Authors: Wu Luhua , Wang Shijie , Bai Xiaoyong , Chen Fei , Li Chaojun , Ran Chen , Zhang Sirui
Published: August 2022

Identifying the impacts of climatic factors on runoff change has become a central topic in climate and hydrology research. This issue, however, has received minimal attention in karst watersheds worldwide. Multi-resolution analysis (MRA), continuous wavelet transform (CWT), cross wavelet transform (XWT) and wavelet transform coherence (WTC) are used to study the teleconnection in time and frequency between climate change and hydrological processes in a typical karst watershed at different time scales. The main results are: (1) All climatic factors exhibit a main cycle at 12-month time scales with runoff changes, but the main periodic bandwidth of rainfall on runoff changes is much wider than that of temperature and evaporation, indicating that rainfall is the main factor affecting runoff changes. (2) In other cycles, the impact of rainfall on runoff changes is the interlacing phenomena with positive and negative, but the impact of temperature and evaporation on runoff change is mainly negative. (3) The response of runoff to rainfall is in time in the high-energy region and the low-energy significant-correlation region and has shown a positive correlation with a smaller phase angle, but it is slightly lagged at 16-month time scales. Moreover, the runoff change lags behind temperature and evaporation for 1–2 months in those regions. (4) It has been found that there is a strong effect of rainfall over runoff, but a lesser effect of temperature and evaporation over runoff. The study sheds light on the main teleconnections between rainfall, evapotranspiration and surface runoff, which in turn might help to attain the better management of water resources in typical karst watersheds.
Diagnostic Value of 2-[18F]FDG PET/CT in a Patient with Atypical Subacute Thyroiditis: A Case Report
Authors: Kraus Teresa , Hacker Marcus , Langsteger Werner , Li Shuren , Calabretta Raffaella
Published: August 2022

Background: Positron emission tomography/computed tomography (PET/CT) imaging with 2-deoxy-2-[18F]fluoro-d-glucose (2-[18F]FDG) is a sensitive diagnostic imaging modality in oncology and could be a useful diagnostic tool in patients with fever of unknown origin (FUO) or with inflammation of unknown origin (IUO). Case presentation: We report a case of a patient originally presenting with a clinical history of FUO and later with persistent high-sensitivity C-reactive protein (hsCRP) levels, even after antibiotic therapy. The patient underwent 2-[18F]FDG PET/CT to investigate and to localize a possible focus of infection or inflammation. 2-[18F]FDG hotspots were detected in both thyroid lobes. Thyroid diagnostic examinations and follow up were performed. Subacute thyroiditis (SAT) was then diagnosed by thyroid examinations, and other possible causes of FUO or IUO were not found. Conclusion: This case illustrates the potential diagnostic value of 2-[18F]FDG PET/CT in patients with atypical SAT, who originally present with only a clinical history of FUO.
Mechanical Analysis of Deformation Law in the Flange Area of Box-Shaped Parts during Deep Drawing
Authors: Chen Duan , Zhao Changcai , Chen Xiaoyi , Chen Guang
Published: August 2022

The investigation of deformation law is the theoretical basis for analyzing instability wrinkling and forming performance during the sheet-metal-forming process. In order to explore the deformation law in the flange area of box-shaped parts and conduct qualitative and quantitative analysis on stress and strain, it is assumed that the deformation law of the mass point on the zero line of shear stress in the corner area is equal to that of the axisymmetric parts. Based on the basic assumptions that the equivalent strain in the flange area is linear with the radius along the radial direction, the simple linear relationship between in-plane shear stress and geometric parameters and the expressions of stress and strain in each region of the flange area are derived. The theoretical derivation is compared and analyzed through finite element (FE) simulation and process tests. The results demonstrate that the theoretical calculation results are consistent with the trends of experimental and simulation results. The calculation accuracy of equivalent strain is higher than that of stress calculation, which reveals that calculation accuracy is sensitive to the parameters in the material constitutive model. The theoretical analysis has reference significance for exploring the law of deep drawing deformation, optimizing the forming process and guiding the actual production.
Characterization of Phase Separated Planar Lipid Bilayer Membrane by Fluorescence Ratio Imaging and Scanning Probe Microscope
Authors: Okamoto Yukihiro , Hamaguchi Kaito , Watanabe Mayo , Watanabe Nozomi , Umakoshi Hiroshi
Published: August 2022

The lipid membrane forms nanodomains (rafts) and shows heterogeneous properties. These nanodomains relate to significant roles in various cell functions, and thus the analysis of the nanodomains in phase-separated lipid membranes is important to clarify the function and role of the nanodomains. However, the lipid membrane possesses small-sized nanodomains and shows a small height difference between the nanodomains and their surroundings at certain lipid compositions. In addition, nanodomain analysis sometimes requires highly sensitive and expensive apparatus, such as a two-photon microscope. These have prevented the analysis by the conventional fluorescence microscope and by the topography of the scanning probe microscope (SPM), even though these are promising methods in macroscale and microscale analysis, respectively. Therefore, this study aimed to overcome these problems in nanodomain analysis. We successfully demonstrated that solvatochromic dye, LipiORDER, could analyze the phase state of the lipid membrane at the macroscale with low magnification lenses. Furthermore, we could prove that the phase mode of SPM was effective in the visualization of specific nanodomains by properties difference as well as topographic images of SPM. Hence, this combination method successfully gave much information on the phase state at the micro/macro scale, and thus this would be applied to the analysis of heterogeneous lipid membranes.
K-Clique Multiomics Framework: A Novel Protocol to Decipher the Role of Gut Microbiota Communities in Nutritional Intervention Trials
Authors: Mengucci Carlo , Nissen Lorenzo , Picone Gianfranco , Malpuech-Brugère Corinne , Orfila Caroline , Ricciardiello Luigi , Bordoni Alessandra , Capozzi Francesco , Gianotti Andrea
Published: August 2022

The availability of omics data providing information from different layers of complex biological processes that link nutrition to human health would benefit from the development of integrated approaches combining holistically individual omics data, including those associated with the microbiota that impacts the metabolisation and bioavailability of food components. Microbiota must be considered as a set of populations of interconnected consortia, with compensatory capacities to adapt to different nutritional intake. To study the consortium nature of the microbiome, we must rely on specially designed data analysis tools. The purpose of this work is to propose the construction of a general correlation network-based explorative tool, suitable for nutritional clinical trials, by integrating omics data from faecal microbial taxa, stool metabolome (1H NMR spectra) and GC-MS for stool volatilome. The presented approach exploits a descriptive paradigm necessary for a true multiomics integration of data, which is a powerful tool to investigate the complex physiological effects of nutritional interventions.
Research on Gradient-Descent Extended Kalman Attitude Estimation Method for Low-Cost MARG
Authors: Liu Ning , Qi Wenhao , Su Zhong , Feng Qunzhuo , Yuan Chaojie
Published: August 2022

Aiming at the problem of the weak dynamic performance of the gradient descent method in the attitude and heading reference system, the susceptibility to the interference of accelerometers and magnetometers, and the complex calculation of the nonlinear Kalman Filter method, an extended Kalman filter suitable for a low-cost magnetic, angular rate, and gravity (MARG) sensor system is proposed. The method proposed in this paper is a combination of a two-stage gradient descent algorithm and the extended Kalman filter (GDEKF). First, the accelerometer and magnetometer are used to correct the attitude angle according to the two-stage gradient descent algorithm. The obtained attitude quaternion is combined with the gyroscope measurement value as the observation vector of EKF and the calculated attitude of the gyroscope and the bias of the gyroscope are corrected. The elimination of the bias of the gyroscope can further improve the stability of the attitude observation results. Finally, the MARG sensor system was designed for mathematical model simulation and hardware-in-the-loop simulation to verify the performance of the filter. The results show that compared with the gradient descent method, it has better anti-interference performance and dynamic performance, and better measurement accuracy than the extended Kalman filter.
Treadmill Stepping after Epidural Stimulation Cessation in Decerebrated Cats
Authors: Merkulyeva Natalia , Lyakhovetskii Vsevolod , Gorskii Oleg , Musienko Pavel
Published: August 2022

Summary: It was repeatedly shown that the locomotion evoked by epidural-induced electrical stimulation can last for a certain amount of time after stimulation cessation in decerebrated and spinal animals. This so-called after-stepping reflects the maintenance level for the activation of locomotor neuronal circuitry, but only scarce information exists about after-stepping peculiarities. We provide a comparative investigation of after-stepping and stepping under epidural stimulation using electromyographic and kinematic signals as well as ground reaction forces in 16 decerebrated cats. Our principal findings are as follows: (1) the ground reaction forces decrease more after epidural stimulation cessation compared to anterior–posterior limb movements; (2) the step cycle duration is longer for after-steps; (3) the electromyographic signal of the extensor gastrocnemius lateralis muscle during after-stepping decreases faster compared to the signal from the flexors iliopsoas and tibialis anterior and to the extensor soleus muscle; and (4) electromyographic stability is reduced after epidural stimulation cessation. We suppose that different levels of the spinal central pattern generator can be differently attenuated after external trigger cessation. These data could be important for the elaboration of locomotor models and for rehabilitation techniques. New Findings: Our new findings come from comparative investigations of the so-called after-stepping (locomotion after electrical stimulation cessation) and locomotion observed during epidural-induced electrical stimulation. Our new findings are as follows: after epidural stimulation cessation, (1) the ground reaction forces decrease faster compared to anterior–posterior limb movements; (2) the electromyographic signal of the extensor gastrocnemius lateralis muscle decreases faster compared to the signals from the flexors iliopsoas and tibialis anterior and to the extensor soleus muscle; and (3) electromyographic stability is reduced.
Graphene-Modified Co-B-P Catalysts for Hydrogen Generation from Sodium Borohydride Hydrolysis
Authors: Jia Xinlei , Sang Zhen , Sun Lixian , Xu Fen , Pan Hongge , Zhang Chenchen , Cheng Riguang , Yu Yuqian , Hu Haopan , Kang Li , Bu Yiting
Published: August 2022

Sodium borohydride (NaBH4) is considered a good candidate for hydrogen generation from hydrolysis because of its high hydrogen storage capacity (10.8 wt%) and environmentally friendly hydrolysis products. However, due to its sluggish hydrogen generation (HG) rate in the water, it usually needs an efficient catalyst to enhance the HG rate. In this work, graphene oxide (GO)-modified Co-B-P catalysts were obtained using a chemical in situ reduction method. The structure and composition of the as-prepared catalysts were characterized, and the catalytic performance for NaBH4 hydrolysis was measured as well. The results show that the as-prepared catalyst with a GO content of 75 mg (Co-B-P/75rGO) exhibited an optimal catalytic efficiency with an HG rate of 12087.8 mL min−1 g−1 at 25 °C, far better than majority of the findings that have been reported. The catalyst had a good stability with 88.9% of the initial catalytic efficiency following 10 cycles. In addition, Co-, B-, and P-modified graphene showed a synergistic effect improving the kinetics and thermodynamics of NaBH4 hydrolysis with a lower activation energy of 28.64 kJ mol−1. These results reveal that the GO-modified Co-B-P catalyst has good potential for borohydride hydrolysis applications.
The Theory of Surface-Enhanced Raman Spectroscopy on Organic Semiconductors: Graphene
Authors: Lombardi John R.
Published: August 2022

Drawing on a theoretical expression previously derived for general semiconductor substrates, we examine the surface-enhancement of the Raman signal (SERS) when the substrate is chosen to be monolayer graphene. The underlying theory involves vibronic coupling, originally proposed by Herzberg and Teller. Vibronic coupling of the allowed molecular transitions with the charge-transfer transitions between the molecule and the substrate has been shown to be responsible for the SERS enhancement in semiconductor substrates. We then examine such an expression for the Raman enhancement in monolayer graphene, which is dependent on the square of the derivative of the density of states of the graphene. On integration, we find that the discontinuity of the density-of-states function leads to a singularity in the SERS intensity. Knowledge of the location of this resonance allows us to maximize the Raman intensity by careful alignment of the doping level of the graphene substrate with the charge-transfer transition.
Editorial for the Special Issue on “Graphene-Related Materials: Synthesis and Applications”
Authors: Otyepka Michal , Giannakoudakis Dimitrios A. , Bakandritsos Aristides
Published: August 2022

Since the groundbreaking discovery of graphene by Geim and Novoselov in 2004, there has been continuous research focused on the utilization of graphene (GR) and graphene-related materials (GRms) in technologically high-impact applications, spanning from electronics, sensing, and spintronics, to catalysis, energy storage, and environmental remediation [...]
Application of CRISPR-Cas9 Gene Editing for HIV Host Factor Discovery and Validation
Authors: Cisneros William J. , Cornish Daphne , Hultquist Judd F.
Published: August 2022

Human Immunodeficiency Virus (HIV) interacts with a wide array of host factors at each stage of its lifecycle to facilitate replication and circumvent the immune response. Identification and characterization of these host factors is critical for elucidating the mechanism of viral replication and for developing next-generation HIV-1 therapeutic and curative strategies. Recent advances in CRISPR-Cas9-based genome engineering approaches have provided researchers with an assortment of new, valuable tools for host factor discovery and interrogation. Genome-wide screening in a variety of in vitro cell models has helped define the critical host factors that play a role in various cellular and biological contexts. Targeted manipulation of specific host factors by CRISPR-Cas9-mediated gene knock-out, overexpression, and/or directed repair have furthermore allowed for target validation in primary cell models and mechanistic inquiry through hypothesis-based testing. In this review, we summarize several CRISPR-based screening strategies for the identification of HIV-1 host factors and highlight how CRISPR-Cas9 approaches have been used to elucidate the molecular mechanisms of viral replication and host response. Finally, we examine promising new technologies in the CRISPR field and how these may be applied to address critical questions in HIV-1 biology going forward.
Volume-Associated Clinical and Histopathological Effects of Intranasal Instillation in Syrian Hamsters: Considerations for Infection and Therapeutic Studies
Authors: Forero Catalina , Ritter Jana M. , Seixas Josilene Nascimento , Coleman-McCray JoAnn D. , Brake Marie , Condrey Jillian A. , Tansey Cassandra , Welch Stephen R. , Genzer Sarah C. , Spengler Jessica R.
Published: August 2022

Syrian hamsters are a key animal model of SARS-CoV-2 and other respiratory viruses and are useful for the evaluation of associated medical countermeasures. Delivery of an infectious agent or intervention to the respiratory tract mirrors natural routes of exposure and allows for the evaluation of clinically relevant therapeutic administration. The data to support instillation or inoculation volumes are important both for optimal experimental design and to minimize or avoid effects of diluent alone, which may compromise both data interpretation and animal welfare. Here we investigate four intranasal (IN) instillation volumes in hamsters (50, 100, 200, or 400 µL). The animals were monitored daily, and a subset were serially euthanized at one of four pre-determined time-points (1, 3, 7, and 14 days post-instillation). Weight, temperature, oxygen saturation, CBC, radiographs, and respiratory tissue histopathology were assessed to determine changes associated with instillation volume alone. With all the delivery volumes, we found no notable differences between instilled and non-instilled controls in all of the parameters assessed, except for histopathology. In the animals instilled with 200 or 400 µL, inflammation associated with foreign material was detected in the lower respiratory tract indicating that higher volumes may result in aspiration of nasal and/or oropharyngeal material in a subset of animals, resulting in IN instillation-associated histopathology.
Development of Novel Unfolding Film System of Itopride Hydrochloride Using Box-Behnken Design—A Gastro Retentive Approach
Authors: Alaithan Shaima , Naveen Nimbagal Raghavendra , Goudanavar Prakash S. , Bhavani Penmetsa Durga , Ramesh Beveenahalli , Koppuravuri Naga Prashant , Fattepur Santosh , Sreeharsha Nagaraja , Nair Anroop B. , Aldhubiab Bandar E. , Shinu Pottathil , Almuqbil Rashed M.
Published: August 2022

Currently, gastro-retentive dosage forms achieved a remarkable position among the oral drug delivery systems. This is a broadly used technique to hold the drug delivery systems for a long duration in the gastro intestine (GI) region, slow drug delivery, and overcome other challenges related to typical oral delivery such as low bioavailability. The current work aimed to formulate and characterize a new expandable gastro-retentive system through Itopride Hydrochloride (IH)’s unfolding process for controlled release. The IH-loaded unfolding film formulation was optimized using the Box-Behnken design for folding endurance and length of tested layer (LTL). Initially, the formulation was made using several anti-adhesive additives to promote the unfolding mechanism. Citric acid and sodium bicarbonate were selected as anti-adhesives based on these results. The enfolded film in a capsule shell was shown to unroll in the stomach fluids and render drug delivery up to 12 h in acidic conditions. A fabricated system should have dimensions more than the size of the relaxed pyloric sphincter, and as required, >20 mm LTL was identified. This further confirms that the residence period in the stomach is irrelevant to the fed or fasted condition. Based on desirability criteria, the formulation containing 143.83, 0.7982, and 14.6096 Eudragit L100, PEG, and sodium bicarbonate are selected as optimized formulations (O-IH-UF). The optimized formulation was further analyzed for various parameters such as tensile strength, mechanical strength, unfolding nature, degradability, and in vitro release studies. The pharmacokinetic study revealed greater AUC (area under the curve) and long half-life with the designed O-IH-UF formulation, confirming that the unfolding film type can be a favorable drug system for enhancing the bioavailability of low soluble drugs. The results showed that unfolding types of gastro retentive systems could potentiate the drugs with stability issues in an alkaline medium or those with absorption in acidic conditions.
Radiation Dosimetry of Theragnostic Pairs for Isotopes of Iodine in IAZA
Authors: Jans Hans-S. , Stypinski Daria , Kumar Piyush , Mercer John R. , McQuarrie Stephen A. , McEwan Alexander J. B. , Wiebe Leonard I.
Published: August 2022

Theragnostic pairs of isotopes are used to infer radiation dosimetry for a therapeutic radiopharmaceutical from a diagnostic imaging study with the same tracer molecule labelled with an isotope better suited for the imaging task. We describe the transfer of radiation dosimetry from the diagnostic radioiodine isotope 123I, labelled for the hypoxia tracer molecule iodoazomycin arabinoside ([123I]IAZA), to isotopes 131I (therapeutic) and 124I (PET imaging). Uncertainties introduced by the dissimilar isotope half-lives are discussed in detail. Radioisotope dosimetries for [123I]IAZA were obtained previously. These data are used here to calculate residence times for 131I and 124I and their uncertainties. We distinguish two cases when extrapolating to infinity: purely physical decay (case A) and physical decay plus biological washout (case B). Organ doses were calculated using the MIRD schema with the OLIDNA/EXM code. Significant increases in some organ doses (in mSv per injected activity) were found for 131I and 124I. The most affected organs were the intestinal walls, thyroid, and urinary bladder wall. Uncertainty remained similar to 123I for case A but considerably greater for case B, especially for long biological half-lives (GI tract). Normal tissue dosimetries for IAZA must be considered carefully when substituting isotope species. A long biological half-life can significantly increase dosimetric uncertainties. These findings are relevant when considering PET imaging studies with [124I]IAZA or therapeutic administration of [131I]IAZA.
Inhibition of HSP90 Preserves Blood–Brain Barrier Integrity after Cortical Spreading Depression
Authors: Palomino Seph M. , Levine Aidan A. , Wahl Jared , Liktor-Busa Erika , Streicher John M. , Largent-Milnes Tally M.
Published: August 2022

Cortical spreading depression (CSD) is a pathophysiological mechanism underlying headache disorders, including migraine. Blood–brain barrier (BBB) permeability is increased during CSD. Recent papers have suggested that heat shock proteins (HSP) contribute to the integrity of the blood–brain barrier. In this study, the possible role of HSP90 in CSD-associated blood–brain barrier leak at the endothelial cell was investigated using an in vitro model, for the blood–endothelial barrier (BEB), and an in vivo model with an intact BBB. We measured barrier integrity using trans endothelial electric resistance (TEER) across a monolayer of rodent brain endothelial cells (bEnd.3), a sucrose uptake assay, and in situ brain perfusion using female Sprague Dawley rats. CSD was induced by application of 60 mM KCl for 5 min in in vitro experiments or cortical injection of KCl (1 M, 0.5 µL) through a dural cannula in vivo. HSP90 was selectively blocked by 17-AAG. Our data showed that preincubation with 17-AAG (1 µM) prevented the reduction of TEER values caused by the KCl pulse on the monolayer of bEnd.3 cells. The elevated uptake of 14C-sucrose across the same endothelial monolayer induced by the KCl pulse was significantly reduced after preincubation with HSP90 inhibitor. Pre-exposure to 17-AAG significantly mitigated the transient BBB leak after CSD induced by cortical KCl injection as determined by in situ brain perfusion in female rats. Our results demonstrated that inhibition of HSP90 with the selective agent 17-AAG reduced CSD-associated BEB/BBB paracellular leak. Overall, this novel observation supports HSP90 inhibition mitigates KCl-induced BBB permeability and suggests the development of new therapeutic approaches targeting HSP90 in headache disorders.
Sodium Alginate/Chitosan Scaffolds for Cardiac Tissue Engineering: The Influence of Its Three-Dimensional Material Preparation and the Use of Gold Nanoparticles
Authors: Beltran-Vargas Nohra E. , Peña-Mercado Eduardo , Sánchez-Gómez Concepción , Garcia-Lorenzana Mario , Ruiz Juan-Carlos , Arroyo-Maya Izlia , Huerta-Yepez Sara , Campos-Terán José
Published: August 2022

Natural biopolymer scaffolds and conductive nanomaterials have been widely used in cardiac tissue engineering; however, there are still challenges in the scaffold fabrication, which include enhancing nutrient delivery, biocompatibility and properties that favor the growth, maturation and functionality of the generated tissue for therapeutic application. In the present work, different scaffolds prepared with sodium alginate and chitosan (alginate/chitosan) were fabricated with and without the addition of metal nanoparticles and how their fabrication affects cardiomyocyte growth was evaluated. The scaffolds (hydrogels) were dried by freeze drying using calcium gluconate as a crosslinking agent, and two types of metal nanoparticles were incorporated, gold (AuNp) and gold plus sodium alginate (AuNp+Alg). A physicochemical characterization of the scaffolds was carried out by swelling, degradation, permeability and infrared spectroscopy studies. The results show that the scaffolds obtained were highly porous (>90%) and hydrophilic, with swelling percentages of around 3000% and permeability of the order of 1 × 10−8 m2. In addition, the scaffolds proposed favored adhesion and spheroid formation, with cardiac markers expression such as tropomyosin, troponin I and cardiac myosin. The incorporation of AuNp+Alg increased cardiac protein expression and cell proliferation, thus demonstrating their potential use in cardiac tissue engineering.
Thermal and Rheological Properties of Gluten-Free, Starch-Based Model Systems Modified by Hydrocolloids
Authors: Megusar Polona , Stopar David , Poklar Ulrih Natasa , Dogsa Iztok , Prislan Iztok
Published: August 2022

Obtaining good-quality gluten-free products represents a technological challenge; thus, it is important to understand how and why the addition of hydrocolloids influences the properties of starch-based products. To obtain insight into the physicochemical changes imparted by hydrocolloids on gluten-free dough, we prepared several suspensions with different corn starch/potato starch/hydroxpropyl methyl cellulose/xanthan gum/water ratios. Properties of the prepared samples were determined by differential scanning calorimetry and rheometry. Samples with different corn/potato starch ratios exhibited different thermal properties. Xanthan gum and HPMC (hydroxypropyl methyl cellulose) exhibited a strong influence on the rheological properties of the mixtures since they increased the viscosity and elasticity. HPMC and xanthan gum increased the temperature of starch gelatinization, as well as they increased the viscoelasticity of the starch model system. Although the two hydrocolloids affected the properties of starch mixtures in the same direction, the magnitude of their effects was different. Our results indicate that water availability, which plays a crucial role in the starch gelatinization process, could be modified by adding hydrocolloids such as, hydroxypropyl methyl cellulose and xanthan gum. By adding comparatively small amounts of the studied hydrocolloids to starch, one can achieve similar thermo-mechanical effects by the addition of gluten. Understanding these effects of hydrocolloids could contribute to the development of better quality gluten-free bread with optimized ingredient content.
Economical Chemical Recycling of Complex PET Waste in the Form of Active Packaging Material
Authors: Volmajer Valh Julija , Stopar Dimitrije , Selaya Berodia Ignacio , Erjavec Alen , Šauperl Olivera , Fras Zemljič Lidija
Published: August 2022

Since millions of tons of packaging material cannot be recycled in conventional ways, most of it ends up in landfills or even dumped into the natural environment. The researched methods of chemical depolymerization therefore open a new perspective for the recycling of various PET materials, which are especially important for packaging. Food preservative packaging materials made from PET plastics are complex, and their wastes are often contaminated, so there are no sophisticated solutions for them in the recycling industry. After integrating the biopolymer chitosan, which is derived from natural chitin, as an active surface additive in PET materials, we discovered that it not only enriches the packaging material as a microbial inhibitor to reduce the bacteria Staphylococcus aureus and Escherichia coli, thus extending the shelf life of the contained food, but also enables economical chemical recycling by alkaline or neutral hydrolysis, which is an environmentally friendly process. Alkaline hydrolysis at a high temperature and pressure completely depolymerizes chitosan-coated PET packaging materials into pure terephthalic acid and charcoal. The products were characterized by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and elemental analysis. The resulting reusable material represents raw materials in chemical, plastic, textile, and other industries, in addition to the antimicrobial function and recyclability itself.
Advanced Materials in 3D/4D Printing Technology
Authors: Pan Houwen Matthew
Published: August 2022

Advances made in 3D printing have opened new avenues for innovation in dental, aerospace, soft robotics, thermal regulation, and flexible electronic devices [...]
Naringin Release from a Nano-Hydroxyapatite/Collagen Scaffold Promotes Osteogenesis and Bone Tissue Reconstruction
Authors: Zuo Yanping , Li Qiwen , Xiong Qiuchan , Li Jing , Tang Chengfang , Zhang Yaochao , Wang Danyang
Published: August 2022

Bone fractures and defects are a major health issue and have reportedly affected over 455 million individuals globally to date. Bone tissue engineering has gained great success in bone defect repair and bone reconstruction based on the use of nano-hydroxyapatite (nHA) or collagen (COL). Both nHA and COL exhibit osteogenic induction capacity to support bone tissue regeneration; however, the former suffers from poor flexibility and the latter lacks mechanical strength. Biological scaffolds created by combining nHA and COL (nHA/COL) can overcome the drawbacks imposed by individual materials and, therefore, have become widely applied in tissue engineering. The composite scaffolds can further promote tissue reconstruction by allowing the loading of various growth factors. Naringin (NG) is a natural flavonoid. Its molecular weight is 580.53 Da, lower than that of many growth factors, and it causes minimal immune responses when being introduced in vivo. In addition, naringin is safe, non-toxic, inexpensive to produce, and has superior bio-properties. In this study, we introduced NG into a nHA/COL scaffold (NG/nHA/COL) and exploited the potentials of the NG/nHA/COL scaffold in enhancing bone tissue regeneration. NG/nHA/COL scaffolds were fabricated by firstly combining nHA and collagen at different compositional ratios, followed by NG encapsulation. NG release tests showed that the scaffold with a nHA/COL mass ratio of 7:3 exhibited the optimal property. The in vitro cell study showed the desirable biocompatibility of the NG/nHA/COL scaffold, and its effective promotion for the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), as proved by an increased alkaline phosphatase (ALP) activity, the formation of more calcium nodules, and a higher expression of osteogenic-related genes involving Osteocalcin (OCN), BMP-2, and Osteopontin (OPN), compared with the control and nHA/COL groups. When administered into rats with skull defects, the NG/nHA/COL scaffold significantly promoted the reconstruction of bone tissues and the early repair of skull defects, indicating the great potential of NG/nHA/COL scaffolds in bone tissue engineering.
Effects of Litsea cubeba Essential Oil Incorporated into Denture Soft Lining Materials
Authors: Songsang Nichakorn , Anunmana Chuchai , Pudla Matsayapan , Eiampongpaiboon Trinuch
Published: August 2022

The antimicrobial properties, cell cytotoxicity and surface hardness of soft lining materials (GC soft liner, Viscogel and Coe comfort) incorporated with various concentrations of Litsea cubeba essential oil (LCEO) were evaluated. The minimum inhibitory concentrations of LCEO against Candida albicans and Streptococcus mutans were 1.25% v/v and 10% v/v, respectively. However, when LCEO was incorporated into the three soft lining materials (GC soft liner, Viscogel and Coe comfort), 10% v/v and 30% v/v of LCEO could inhibit the growth of C. albicans and S. mutans, respectively. The extracts of soft lining materials with 10% and 30% v/v LCEO, 2% chlorhexidine, 30% v/v nystatin and no additive were used for cytotoxicity tests on a human gingival fibroblast cell line. There was no significant difference in cell viability in all groups with additives compared to the no additive group (p > 0.05). Surface hardness increased significantly between 2 h and 7 day incubation times in all groups, including the controls (p < 0.05). A higher LCEO concentration had a dose-dependent effect on the surface hardness of all soft lining materials (p < 0.05). However, the surface hardness of materials with additive remained in accordance with ISO 10139-1. LCEO could be used as a natural product against oral pathogens, without having a negative impact on soft lining materials.
Covalent Organic Framework (COF): A Drug and Carrier to Attenuate Retinal Ganglion Cells Death in an Acute Glaucoma Mouse Model
Authors: Yao Ke , Liang Xin , Zhang Guiyang , Rong Yan , Zhang Qiuxiang , Liao Qiaobo , Zhang Hong , Xi Kai , Wang Junming
Published: August 2022

Purpose: We aim to investigate the use of covalent organic framework (COF) nanoparticles in the local treatment of glaucoma, both as a means of protecting retinal ganglion cells (RGCs), and as a carrier for delayed release of the medication rapamycin following a single intravitreal injection. Methods: a water-dispersible COF, and a COF-based nanoplatform for rapamycin release (COF-Rapa) was constructed. C57BL/6J mice were randomly divided into four groups: intravitreal injection of 1.5 µL normal saline (NS), COF (0.67 ng/µL), rapamycin (300 µM) or COF-Rapa (0.67 ng/µL-300 µM), respectively. The ischemia–reperfusion (I/R) model was established to mimic high intraocular pressure (IOP)-induced retinal injury in glaucoma. Labeling of RGCs by Fluoro-Gold and retinal electroretinogram were used to evaluate retinal function. Immunohistochemistry and Western blotting analyses of retinas were performed. Results: COF nanoparticles were delivered in vitro and in vivo. Six weeks after the COF injection, the number of RGCs was unaffected. In addition, the number of RBPMS-positive RGCs, GFAP-positive astrocytes and Iba1-positive microglia did not differ from the normal control. COF could effectively reduce RGCs death, improve phototransduction function and alleviate the overactivation of microglia compared to NS control after retinal I/R injury. Within six weeks, the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway in the retinas could be inhibited by a single intravitreal injection of COF-Rapa. Compared with single COF administration, COF-Rapa significantly reduced the inflammatory reaction after retinal I/R injury. Conclusions: COF may act as both an RGC protection agent and a carrier for prolonged rapamycin release. This research may lead to the development of novel RGC protection agents and drug delivery techniques, as well as the creation of multifunctional COF-based biomaterials for glaucoma retinopathy.
Deep like the Rivers: Black Women’s Use of Christian Mindfulness to Thrive in Historically Hostile Institutions
Authors: Latunde Yvette C.
Published: August 2022

Historical literature demonstrates that Black women have exhibited a deep commitment to wellness and social change. Black women engage in various forms of mindfulness to sustain themselves as they make changes. There is a dearth of literature on the ways in which Black women in academia who identify as Christians describe Christian mindfulness and their applications of such to promote their own health and wellness in hostile environments. Autoethnography and narrative inquiry were used to describe and analyze the principles and practices a Black academic used to thrive in a historically hostile Christian institution. These findings suggest Christian mindfulness is vast and focused on God’s perspectives and applications of Godly wisdom.
Peatland Plant Spectral Response as a Proxy for Peat Health, Analysis Using Low-Cost Hyperspectral Imaging Techniques
Authors: Stuart Mary B. , Davies Matthew , Hobbs Matthew J. , McGonigle Andrew J. S. , Willmott Jon R.
Published: August 2022

Peatland habitats represent key environmental resources that are a critical component in climate change mitigation strategies. However, many of these environmental settings are facing significant levels of erosion and degradation which, over time, will result in the loss of these key environments. Traditional monitoring techniques for these settings require invasive methods, disrupting the natural environment and potentially leading to further losses if incorrectly administered. In this article, we provide a non-invasive, cost-effective alternative to peatland health monitoring through the implementation of low-cost hyperspectral imaging techniques. Using common peatland plant species as a proxy for underlying peat health, we monitor the spectral response of Sphagnum plants under varying degrees of water stress to document their spectral response under these conditions. For this research, we utilise a low-cost, semi-portable High-Resolution Hyperspectral Imager capable of resolving mm-scale targets in conjunction with the ultra-low-cost Hyperspectral Smartphone that represents a completely accessible fully field portable instrument allowing for rapid and accurate on-site measurements. Both instruments are shown to provide accurate and robust results, capturing subtle changes in spectral response prior to their appearance within visual datasets enabling the use of mitigation and restoration techniques before the onset of more damaging conditions.
The Impacts of Air Quality on Vegetation Health in Dense Urban Environments: A Ground-Based Hyperspectral Imaging Approach
Authors: Qamar Farid , Sharma Mohit S. , Dobler Gregory
Published: August 2022

We examine the impact of changes in ozone (O3), particulate matter (PM2.5), temperature, and humidity on the health of vegetation in dense urban environments, using a very high-resolution, ground-based Visible and Near-Infrared (VNIR, 0.4–1.0 μm with a spectral resolution of 0.75 nm) hyperspectral camera deployed by the Urban Observatory (UO) in New York City. Images were captured at 15 min intervals from 08h00 to 18h00 for 30 days between 3 May and 6 June 2016 with each image containing a mix of dense built structures, sky, and vegetation. Vegetation pixels were identified using unsupervised k-means clustering of the pixel spectra and the time dependence of the reflection spectrum of a patch of vegetation at roughly 1 km from the sensor that was measured across the study period. To avoid illumination and atmospheric variability, we introduce a method that measures the ratio of vegetation pixel spectra to the spectrum of a nearby building surface at each time step relative to that ratio at a fixed time. This “Compound Ratio” exploits the (assumed) static nature of the building reflectance to isolate the variability of vegetation reflectance. Two approaches are used to quantify the health of vegetation at each time step: (a) a solar-induced fluorescence indicator (SIFi) calculated as the simple ratio of the amplitude of the Compound Ratio at 0.75 μm and 0.9 μm, and (b) Principal Component Analysis (PCA) decomposition designed to capture more global spectral features. The time dependence of these vegetation health indicators is compared to that of O3, PM2.5, temperature, and humidity values from a distributed and publicly available in situ air quality sensor network. Assuming a linear relationship between vegetation health indicators and air quality indicators, we find that changes in both SIF indicator values and PC amplitudes show a strong correlation (r2 value of 40% and 47%, respectively) with changes in air quality, especially in comparison with nearby buildings used as controls (r2 value of 1% and 4%, respectively, and with all molecular correlations consistent with zero to within 3σ uncertainty). Using the SIF indicator, O3 and temperature exhibit a positive correlation with changes in photosynthetic rate in vegetation, while PM2.5 and humidity exhibit a negative correlation. We estimate full covariant uncertainties on the coefficients using a Markov Chain Monte Carlo (MCMC) approach and demonstrate that these correlations remain statistically significant even when controlling for the effects of diurnal sun-sensor geometry and temperature variability. This work highlights the importance of quantifying the effects of various air quality parameters on vegetation health in urban environments in order to uncover the complexity, covariance, and interdependence of the numerous factors involved.
Sen2Like: Paving the Way towards Harmonization and Fusion of Optical Data
Authors: Saunier Sébastien , Pflug Bringfried , Lobos Italo , Franch Belen , Louis Jérôme , De Los Reyes Raquel , Debaecker Vincent , Cadau Enrico , Boccia Valentina , Gascon Ferran , Kocaman Sultan
Published: August 2022

Satellite Earth Observation (EO) sensors are becoming a vital source of information for land surface monitoring. The concept of the Virtual Constellation (VC) is gaining interest within the science community owing to the increasing number of satellites/sensors in operation with similar characteristics. The establishment of a VC out of individual missions offers new possibilities for many application domains, in particular in the fields of land surface monitoring and change detection. In this context, this paper describes the Copernicus Sen2Like algorithms and software, a solution for harmonizing and fusing Landsat 8/Landsat 9 data with Sentinel-2 data. Developed under the European Union Copernicus Program, the Sen2Like software processes a large collection of Level 1/Level 2A products and generates high quality Level 2 Analysis Ready Data (ARD) as part of harmonized (Level 2H) and/or fused (Level 2F) products providing high temporal resolutions. For this purpose, we have re-used and developed a broad spectrum of data processing and analysis methodologies, including geometric and spectral co-registration, atmospheric and Bi-Directional Reflectance Distribution Function (BRDF) corrections and upscaling to 10 m for relevant Landsat bands. The Sen2Like software and the algorithms have been developed within a VC establishment framework, and the tool can conveniently be used to compare processing algorithms in combinations. It also has the potential to integrate new missions from spaceborne and airborne platforms including unmanned aerial vehicles. The validation activities show that the proposed approach improves the temporal consistency of the multi temporal data stack, and output products are interoperable with the subsequent thematic analysis processes.
Targets’ Radial and Tangential Velocities Estimation Based on Vortex Electromagnetic Waves
Authors: Li Caipin , Li Shengyuan , You Dong , Peng Wencan , Li Jinwei , Li Yu , Li Qiang , Chen Zhanye
Published: August 2022

The orbital angular momentum (OAM) of a vortex electromagnetic wave (VEW) has gained attention as a newly explored information carrier. OAM modes provide vortex azimuth resolution, which is a new degree of freedom (DOF) in radar application. Due to the special characteristics of the vortex azimuth domain, VEW shares compound Doppler information of two-dimensional (2D) speed. This paper proposes a 2D target velocity estimation method for VEW radar. The Doppler effect of VEW is first analyzed. Based on the relativity of tangential speed and OAM mode, a pulse-by-pulse OAM mode-changing strategy is designed. Then, a modified Radon–Fourier transformation (RFT) is proposed to estimate the compound Doppler frequency while range migration is compensated. In addition, decoupling and ambiguity-solving procedures are applied to the compound Doppler frequency estimation to obtain tangential and radial speed estimations separately. According to the simulation analyses, the effectiveness of the proposed method is verified.
Towards Understanding the Influence of Vertical Water Distribution on Radar Backscatter from Vegetation Using a Multi-Layer Water Cloud Model
Authors: Vermunt Paul C. , Steele-Dunne Susan C. , Khabbazan Saeed , Kumar Vineet , Judge Jasmeet
Published: August 2022

For a good interpretation of radar backscatter sensitivity to vegetation water dynamics, we need to know which parts of the vegetation layer control that backscatter. However, backscatter sensitivity to different depths in the canopy is poorly understood. This is partly caused by a lack of observational data to describe the vertical moisture distribution. In this study, we aimed to understand the sensitivity of L-band backscatter to water at different heights in a corn canopy. We studied changes in the contribution of different vertical layers to total backscatter throughout the season and during the day. Using detailed field measurements, we first determined the vertical distribution of moisture in the plants, and its seasonal and sub-daily variation. Then, these measurements were used to define different sublayers in a multi-layer water cloud model (WCM). To calibrate and validate the WCM, we used hyper-temporal tower-based polarimetric L-band scatterometer data. WCM simulations showed a shift in dominant scattering from the lowest 50 cm to 50–100 cm during the season in all polarizations, mainly due to leaf and ear growth and corresponding scattering and attenuation. Dew and rainfall interception raised sensitivity to upper parts of the canopy and lowered sensitivity to lower parts. The methodology and results presented in this study demonstrate the importance of the vertical moisture distribution on scattering from vegetation. These insights are essential to avoid misinterpretation and spurious artefacts during retrieval of soil moisture and vegetation parameters.