bluuebunny/crossref_metadata_2025 huggingface dataset:
The Synchronous Development Pattern and Type Division of Functional Coupling Coordination and Human Activity Intensity Based on the “Production–Living–Ecological” Space Perspective: A Case Study of Wanzhou District
Authors: Liang Tian , Yang Fei , Luo Yinchen , Fang Mengying , Huang Xi , Zhang Zhiyong , Wen Chuanhao , Ren Xiaohong
Published: October 2022

The coupling and coordinated change characteristics of land-use production, living, and ecological functions (PLEFs) and their relationship with human activity intensity (HAI) in ecologically fragile areas are important to study, especially in promoting the sustainable development of regional land-use and revealing the evolution of the human–land relationship. In this paper, the coupling coordination degree (CCD) model was used to analyze the coordinated development level of PLEF in Wanzhou District from 2000 to 2020. The HAI was measured by the equivalent of construction land. The synchronous development model was introduced to analyze the relationship between them. The results showed that, in Wanzhou District, the PLEFs showed significant spatial distribution differences and evident spatial complementarity. The PLEFs of Wanzhou District were at a good coordination level, but exhibited a downward trend. A spatial pattern of “high in the west and low in the southeast” was presented. The CCD of the production–living function was poor, which is the critical direction of future optimization. The value of HAI in Wanzhou District showed an increasing trend and exhibited a high concentration in the central town and its surrounding regions. According to the synchronous development state of the HAI and the CCD of the PLEFs, Wanzhou District was divided into three development types. The development type of most areas of Wanzhou District was positive, but the area decreased over the past 20 years. Therefore, it is crucial to propose other regulatory strategies for regions with different development types. This research will provide a decision-making reference for promoting the coordination of the PLEFs and alleviating human–land relations in the reservoir area of central and western China, mountainous regions, and similar areas in developing countries.
The Effect of Green Urbanization on Forestry Green Total Factor Productivity in China: Analysis from a Carbon Neutral Perspective
Authors: Wang Fengting , Wang Hao , Liu Cong , Xiong Lichun , Qian Zhiquan
Published: October 2022

Based on panel data from 30 provinces from 2001 to 2018 in China, this paper explores the effects and mechanisms of green urbanization on the forestry green total factor productivity (FGTFP) in the context of carbon neutral strategy using a two-way fixed effects model and instrumental variables. The results show that: Firstly, as a sector with ecological and economic benefits, ignoring carbon sink output tends to make FGTFP overestimated. Secondly, green urbanization has a significant positive contribution effect on FGTFP, and this finding still holds after a series of robustness tests including instrumental variables. Thirdly, green urbanization can indirectly promote FGTFP by stimulating the integration of forestry and tourism and strengthening environmental regulations. Fourthly, there is regional heterogeneity in the impact of green urbanization on FGTFP, i.e., the promotion effect of green urbanization on FGTFP is more significant in non-state forest areas compared with state-owned forest areas. Based on the above conclusions, the following countermeasures are proposed: firstly, attaching importance to green urbanization and strengthening environmental constraints; secondly, relying on green urbanization to drive the integration of forestry and tourism; thirdly, actively promoting the construction of green urbanization and green development of forestry in non-state forest areas, while vigorously developing the carbon sink economy to crack the transformation dilemma of backward state forest areas.
Applicable Framework for Evaluating Urban Vitality with Multiple-Source Data: Empirical Research of the Pearl River Delta Urban Agglomeration Using BPNN
Authors: Huang Xuefeng , Jiang Penghui , Li Manchun , Zhao Xin
Published: October 2022

Urban vitality is a mirror reflection of ‘urban disease’ in cities. The research on urban vitality has made great progress in evaluation frameworks; however, these frameworks cannot jointly account for the macro and micro performance of urban vitality. It is better to establish an integrated evaluation framework for this topic. This paper defines urban vitality as the comprehensive strength to support dense and diverse activities based on urban development and the urban environment, and subsequently develops an integrated framework including economic, social, cultural, and spatial dimensions. With the nonlinear evaluation model of a back propagation neural network, we further presented the result of an application on the Pearl River Delta urban agglomeration. Our profiling results illustrate the core-edge structure of urban vitality. There are differences in vitality performance within built-up areas, which shows that areas with urban landscapes and excellent infrastructure are more vibrant. The integrated framework with good applicability improves the evaluation of urban vitality that is crucial to city examination and urban planning. Hence, this study provides a comprehensive reference for optimizing resource allocation and promoting sustainable development.
Public–Private Interactions in Privacy Governance
Authors: Peng Shin-yi
Published: October 2022

This paper addresses the possible roles of private actors when privacy paradigms are in flux. If the traditional “informed consent”-based government-dominated approaches are ill-suited to the big data ecosystem, can private governance fill the gap created by state regulation? In reality, how is public–private partnership being implemented in the privacy protection frameworks? This paper uses cases from APEC’s Cross-Border Privacy Rules (CBPR) and the EU’s General Data Protection Regulation (GDPR) as models for exploration. The analysis in this paper demonstrates the fluidity of interactions across public and private governance realms. Self-regulation and state regulation are opposing ends of a regulatory continuum, with CBPR-type “collaboration” and GDPR-type “coordination” falling somewhere in the middle. The author concludes that there is an evident gap between private actors’ potential governing functions and their current roles in privacy protection regimes. Looking to the future, technological developments and market changes call for further public–private convergence in privacy governance, allowing the public authority and the private sector to simultaneously reshape global privacy norms.
Evaluation of Low Volume Roads Surfaced with 100% RAP Millings
Authors: Hand Adam J. T. , Ragavan Prathapan , Elias Nicole G. , Hajj Elie Y. , Sebaaly Peter E.
Published: October 2022

The sustainability of roadway construction has rapidly been gaining attention within the pavement industry. The pavements examined in this study are in a Northern Nevada county with many of the roadways categorized as low volume roads. The county began surfacing rural roads with 100% Reclaimed Asphalt Pavement (RAP) millings, without any design considerations for decades. These pavements have provided satisfactory performance with little to no maintenance for their intended purpose for 25–30 years. The presented research revealed RAP milling surfaced roads with layer coefficients between 0.18 and 0.30, and design thicknesses ranging from 5 to 11 inches.
Ru Single Atoms on One-Dimensional CF@g-C3N4 Hierarchy as Highly Stable Catalysts for Aqueous Levulinic Acid Hydrogenation
Authors: Yang Ying , Zhang Suoying , Gu Lin , Hao Shijie
Published: October 2022

Herein, we report a stable catalyst with Ru single atoms anchored on a one-dimensional carbon fiber@graphitic carbon nitride hierarchy, by assembling wet wipes composed of fiber-derived carbon fiber (CF), melamine-derived graphitic carbon nitride (g-C3N4) and RuCl3 before NaBH4 reduction. The atomically dispersed Ru species (3.0 wt%) are tightly attached via N-coordination provided by exterior g-C3N4 nanosheets, and further stabilized by the interior mesoporous CF. The obtained CF@g-C3N4–Ru SAs catalyst can be cycled six times without notable leaching of Ru or loss of GVL yield in the acidic media. This catalyst is more stable than Ru nanoparticles supported on CF@g-C3N4, as well as Ru single atoms anchored on CF and g-C3N4, and proves to be one of the most efficient metal catalysts for aqueous LA hydrogenation to γ-valerolactone (GVL). The isolated Ru atoms by strong N-coordination, and their enhanced electron/mass transfer afforded by the one-dimensional hierarchy, can be responsible for the excellent durability of CF@g-C3N4–Ru SAs under harsh reaction conditions.
Numerical Simulation and Analytical Prediction of Residual Strength for Elbow Pipes with Erosion Defects
Authors: Sun Chao , Wang Qi , Li Yuelin , Li Yingqi , Liu Yuechan
Published: October 2022

It is well known that the safety and reliability of pipeline transportation are crucial. We are aiming at the problem that the residual life and residual strength of the defective elbow pipes are difficult to predict and usually need to be obtained through experiments. Consequently, a combined method of numerical simulation technology combined with a genetic algorithm to optimize neural network extreme learning machine (GA-ELM) is proposed. Firstly, the erosion characteristics of elbow pipes with different defects under the conditions of different impurity particle flow rates, particle sizes, and mass flow rates are analyzed by numerical simulation. At the same time, the effects of erosion defects of different sizes on the equivalent stress and residual strength of elbow pipes are also studied. Based on numerical simulation data, the extreme learning machine prediction model optimized by a genetic algorithm is used to predict the erosion rate, residual life, and residual strength and compared with the traditional ELM network model. The results show that residual strength of the elbow pipes with the increase of the depth and length of the defect, and increases with the increase of the width of the defect; the GA-ELM model can not only effectively predict the erosion rate, residual life and residual strength of defective elbow pipes, moreover its prediction accuracy is better than the traditional ELM model.
Effect of Sleeper-Ballast Particle Contact on Lateral Resistance of Concrete Sleepers in Ballasted Railway Tracks
Authors: Chalabii Jafar , Movahedi Rad Majid , Hadizadeh Raisi Ebrahim , Esfandiari Mehni Reza
Published: October 2022

Although a sleeper makes a great contribution to the lateral resistance of ballasted tracks, in this regard, limited studies have been carried out on the effect of its contact surface with ballast aggregates. The current paper is dedicated to evaluating the effect of sleeper shape on the lateral resistance of ballasted track through discrete element modelling (DEM). For this purpose, firstly, a DEM model was validated based on the experimental results. Then, a sensitivity analysis was undertaken on the effect of the different contact areas that a standard concrete sleeper faces with the crib, shoulder and underlying ballast aggregates on lateral resistance of a single sleeper. As the main result of the current study, a high accurate regression equation for constant weight 319.2 kg and constant density 2500 kg/m3 of the sleepers was fitted between different sleeper contact areas and the maximum lateral resistance of a concrete sleeper for 3.5 mm lateral displacement in ballasted railway tracks. The obtained results showed that the effect of the sleeper’s head area compared to the underlying area of the sleeper and the head area of the sleeper compared to the sleeper’s side area in terms of lateral resistance are 8.2 times and 14.5 times more, respectively.
Nanomechanical Mapping of Hard Tissues by Atomic Force Microscopy: An Application to Cortical Bone
Authors: Bontempi Marco , Salamanna Francesca , Capozza Rosario , Visani Andrea , Fini Milena , Gambardella Alessandro
Published: October 2022

Force mapping of biological tissues via atomic force microscopy (AFM) probes the mechanical properties of samples within a given topography, revealing the interplay between tissue organization and nanometer-level composition. Despite considerable attention to soft biological samples, constructing elasticity maps on hard tissues is not routine for standard AFM equipment due to the difficulty of interpreting nanoindentation data in light of the available models of surface deformation. To tackle this issue, we proposed a protocol to construct elasticity maps of surfaces up to several GPa in moduli by AFM nanoindentation using standard experimental conditions (air operation, nanometrically sharp spherical tips, and cantilever stiffness below 30 N/m). We showed how to process both elastic and inelastic sample deformations simultaneously and independently and quantify the degree of elasticity of the sample to decide which regime is more suitable for moduli calculation. Afterwards, we used the frequency distributions of Young’s moduli to quantitatively assess differences between sample regions different for structure and composition, and to evaluate the presence of mechanical inhomogeneities. We tested our method on histological sections of sheep cortical bone, measuring the mechanical response of different osseous districts, and mapped the surface down to the single collagen fibril level.
Manufacturing and Characterization of Wide-Bundle Bamboo Scrimber: A Comparison with Other Engineered Bamboo Composites
Authors: Hu Yuan , Xiong Luyao , Li Yanbo , Semple Kate , Nasir Vahid , Pineda Hugo , He Mei , Dai Chunping
Published: October 2022

Controlling the variability in mat structure and properties in bamboo scrimber (BS) is key to producing the product for structural applications, and wide strip scrimber (WBS) is an effective approach. In this study, the effects of scrimmed bamboo bundle morphology and product density on the properties of WBS were investigated. WBS panels were manufactured and tested using wide (200 to 250 mm) bamboo strips with different fiberization intensity. Maximum strength properties (flexural, compressive, and shear strength), and lowest thickness swelling and water absorption were achieved with three or four passes due to the higher resin absorption by strips. For balanced product cost and performance, we recommend 1–2 fiberization passes and a panel density of 0.9–1.0 g/cm3. Panel mechanical properties were compared with other common bamboo composites. Bamboo scrimber products were highly variable in properties due to differing manufacturing processes, element treatments, and suboptimal mat structure. Products including laminated bamboo lumber and flattened bamboo made from nonfiberized elements show markedly different relationships between strength and elastic properties mostly due to inadequate bonding between the laminae, which causes premature bond-line failure. This study helped improve the understanding of the structure–property relationship of engineered bamboo products while providing insights into process optimization.
Physical and Mechanical Properties of Novel Porous Ecological Concrete Based on Magnesium Phosphate Cement
Authors: Zhao Shuaiyu , Zhang Dongpo , Li Yaqiang , Gao Hang , Meng Xinmiao
Published: October 2022

Ecological concrete could reduce the environment impacts of the tremendous construction of infrastructures due to its favorability to plant growth. Nonetheless, the alkalinity of the ecological concrete is usually too high when using ordinary Portland cement (OPC). To solve this problem, the magnesium ammonium phosphate cement (MPC) was used to prepare a novel porous ecological concrete instead of OPC. The pH value and compressive strength of MPC were analyzed and the pore structure was evaluated. The chemical composition and morphology were investigated by an X-ray diffraction test and scanning electron microscope observation. In addition, the void ratio, compressive strength and planting-growing characteristic of MPC-based porous ecological concrete were also studied. The pH value of the MPC suspension ranged from 6.8 to 8.5, which was much lower than that of OPC. The pH value of MPC gradually increased with the increment of phosphorus/magnesium molar ratio (P/M) and the compressive strength reached a maximum value of 49.2 MPa when the P/M value was 1/4. Fly ash (FA) and ground blast furnace slag (GBFS) could improve the pore structure and compressive strength; however, the pH value was slightly increased. As the paste-to-aggregate ratio increased, the void ratio of concrete gradually decreased, while the compressive strength gradually increased. The meadow grass was planted in the MPC-based ecological concrete, and the seeds germinated in one week and showed a better growth status than those planted in the OPC-based ecological concrete.
The Partial Inverse Spectral and Nodal Problems for Sturm–Liouville Operators on a Star-Shaped Graph
Authors: Wei Xian-Biao , Cheng Yan-Hsiou , Wang Yu-Ping
Published: October 2022

We firstly prove the Horváth-type theorem for Sturm–Liouville operators on a star-shaped graph and then solve a new partial inverse nodal problem for this operator. We give some algorithms to recover this operator from a dense nodal subset and prove uniqueness theorems from paired-dense nodal subsets in interior subintervals having a central vertex. In particular, we obtain some uniqueness theorems by replacing the information of nodal data on some fixed edge with part of the eigenvalues under some conditions.
Effect of Previous Frozen Storage, Canning Process and Packing Medium on the Fatty Acid Composition of Canned Mackerel
Authors: Prego Ricardo , Trigo Marcos , Martínez Beatriz , Aubourg Santiago P.
Published: October 2022

This study addressed the fatty acid (FA) composition of canned Atlantic mackerel (Scomber scombrus). In it, the effect of prior frozen storage (6 months at −18 °C), different packing media (water, brine, and sunflower, refined and extra virgin olive oils), and canning procedure was investigated. As a result, the canning procedure led to a decrease (p < 0.05) in saturated FA (STFA) levels, an increase (p < 0.05) in polyunsaturated FA (PUFA) and total ω3 FA values, and higher PUFA/STFA and ω3/ω6 ratio values. Concerning the packing medium effect, the great presence of C18:2ω6 in sunflower oil led to high PUFA and PUFA/STFA values and low ω3/ω6 ratios when compared to other packing media. However, the high presence of C18:1ω9 in both olive oils tested did not lead to remarkable increases (p > 0.05) of this FA presence. Additionally, the presence of total ω3 FAs, C20:5ω3 and C22:6ω3 did not provide differences in canned fish muscle as a result of using different packing media. In all canned samples, ω3/ω6 values were included in the 8.2–10.8 range. Prior frozen storage did not have a substantial effect (p > 0.05) on the FA group (STFA, monounsaturated FA, PUFA, total ω3 FA) and FA ratio (PUFA/STFA and ω3/ω6) values.
Protective Effects of Topical Administration of Laminarin in Oxazolone-Induced Atopic Dermatitis-like Skin Lesions
Authors: Lee Tae-Kyeong , Kim Dae Won , Ahn Ji Hyeon , Lee Choong-Hyun , Lee Jae-Chul , Lim Soon Sung , Kang Il Jun , Hong Seongkweon , Choi Soo Young , Won Moo-Ho , Park Joon Ha
Published: October 2022

Laminarin is a polysaccharide isolated from brown marine algae and has a wide range of bioactivities, including immunoregulatory and anti-inflammatory properties. However, the effects of laminarin on atopic dermatitis have not been demonstrated. This study investigated the potential effects of topical administration of laminarin using a Balb/c mouse model of oxazolone-induced atopic dermatitis-like skin lesions. Our results showed that topical administration of laminarin to the ear of the mice improved the severity of the dermatitis, including swelling. Histological analysis revealed that topical laminarin significantly decreased the thickening of the epidermis and dermis and the infiltration of mast cells in the skin lesion. Serum immunoglobulin E levels were also significantly decreased by topical laminarin. Additionally, topical laminarin significantly suppressed protein levels of oxazolone-induced proinflammatory cytokines, such as interleukin-1β, tumor necrosis factor-α, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1α in the skin lesion. These results indicate that topical administration of laminarin can alleviate oxazolone-induced atopic dermatitis by inhibiting hyperproduction of IgE, mast cell infiltration, and expressions of proinflammatory cytokines. Based on these findings, we propose that laminarin can be a useful candidate for the treatment of atopic dermatitis.
Pervaporation Membranes for Seawater Desalination Based on Geo–rGO–TiO2 Nanocomposites: Part 2—Membranes Performances
Authors: Subaer Subaer , Fansuri Hamzah , Haris Abdul , Misdayanti Misdayanti , Ramadhan Imam , Wibawa Teguh , Putri Yulprista , Ismayanti Harlyenda , Setiawan Agung
Published: October 2022

This is part 2 of the research on pervaporation membranes for seawater desalination based on Geo–rGO–TiO2 nanocomposite. The quality of the Geo–rGO–TiO2 pervaporation membranes (PV), as well as the suitability of the built pervaporation system, is thoroughly discussed. The four membranes described in detail in the first article were tested for their capabilities using the parameters turbidity, salinity, total suspended solids (TSS), and electrical conductivity (EC). The membranes’ flux permeate was measured as a function of temperature, and salt rejection was calculated using the electrical conductivity values of the feed and permeate. Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) techniques were used to investigate changes in the chemical composition and internal structure of the membranes after use in pervaporation systems. The morphology of the membrane’s surfaces was examined by means of scanning electron microscopy (SEM), and the elemental distribution was observed by using X-ray mapping and energy dispersive spectroscopy (EDS). The results showed that the pervaporation membrane of Geo–rGO–TiO2 (1, 3) achieved a permeate flux as high as 2.29 kg/m2·h with a salt rejection of around 91%. The results of the FTIR and XRD measurements did not show any changes in the functional group and chemical compositions of the membrane after the pervaporation process took place. Long-term pressure and temperature feed cause significant cracking in geopolymer and Geo–TiO2 (3) membranes. SEM results revealed that the surface of all membranes is leached out, and elemental distribution based on X-ray mapping and EDS observations revealed the addition of Na+ ions on the membrane surface. The study’s findings pave the way for more research and development of geopolymers as the basic material for inorganic membranes, particularly with the addition of rGO–TiO2 nanocomposites.
Tensile and Fracture Behavior of Bi-Containing Alloy Sintered on SAE 1010 Steel Sheet
Authors: Song Seung-Hyon , Lee Chang-Soon , Lim Tae-Hwan , Amanov Auezhan , Cho In-Sik
Published: October 2022

The purpose of this study is to investigate the fractural behavior of lead (Pb)-free material containing bismuth (Bi) that was developed to replace the Pb included in sintered copper (Cu)-based alloy for plain bearings. Mechanical properties and microstructure of two different sintered Cu-based alloys (CuSn10Pb10 and CuSn10Bi7) were compared and analyzed. Under tensile load, a CuSn10Pb10 layer is decomposed into powder and changed to form pores leading to an expansion. Therefore, even after tensile elongation, the matrix itself did not stretch, with no work hardening. However, in the case of CuSn10Bi7, a Bi kept its original shape, resulting in it being the same length as the steel plate, where the hardness and strength increased due to the effect of work hardening. These results suggested that the performance of the alloys was different under a high tensile load, where plain bearings usually undergo tensile deformation.
A Tool for Rapid Analysis Using Image Processing and Artificial Intelligence: Automated Interoperable Characterization Data of Metal Powder for Additive Manufacturing with SEM Case
Authors: Bakas Georgios , Dimitriadis Spyridon , Deligiannis Stavros , Gargalis Leonidas , Skaltsas Ioannis , Bei Kyriaki , Karaxi Evangelia , Koumoulos Elias P.
Published: October 2022

A methodology for the automated analysis of metal powder scanning electron microscope (SEM) images towards material characterization is developed and presented. This software-based tool takes advantage of a combination of recent artificial intelligence advances (mask R-CNN), conventional image processing techniques, and SEM characterization domain knowledge to assess metal powder quality for additive manufacturing applications. SEM is being used for characterizing metal powder alloys, specifically by quantifying the diameter and number of spherical particles, which are key characteristics for assessing the quality of the analyzed powder. Usually, SEM images are manually analyzed using third-party analysis software, which can be time-consuming and often introduces user bias into the measurements. In addition, only a few non-statistically significant samples are taken into consideration for the material characterization. Thus, a method that can overcome the above challenges utilizing state-of-the-art instance segmentation models is introduced. The final proposed model achieved a total mask average precision (mAP50) 67.2 at an intersection over union of 0.5 and with prediction confidence threshold of 0.4. Finally, the predicted instance masks are further used to provide a statistical analysis that includes important metrics such as the particle size distinction.
A Specific Interaction between Ionic Liquids’ Cations and Reichardt’s Dye
Authors: Mero Angelica , Guglielmero Luca , Guazzelli Lorenzo , D’Andrea Felicia , Mezzetta Andrea , Pomelli Christian Silvio
Published: October 2022

Solvatochromic probes are often used to understand solvation environments at the molecular scale. In the case of ionic liquids constituted by an anion and a cation, which are designed and paired in order to obtain a low melting point and other desirable physicochemical properties, these two indivisible components can interact in a very different way with the probe. This is the case with one of the most common probes: Reichardt’s Dye. In the cases where the positive charge of the cation is delocalized on an aromatic ring such as imidazolium, the antibonding orbitals of the positively charged aromatic system are very similar in nature and energy to the LUMO of Reichardt’s Dye. This leads to an interesting, specific cation-probe interaction that can be used to elucidate the nature of the ionic liquids’ cations. Parallel computational and experimental investigations have been conducted to elucidate the nature of this interaction with respect to the molecular structure of the cation.
Structural Analysis of the Complex of Human Transthyretin with 3′,5′-Dichlorophenylanthranilic Acid at 1.5 Å Resolution
Authors: Cody Vivian , Truong Jia Q. , Holdsworth Bruce A. , Holien Jessica K. , Richardson Samantha J. , Chalmers David K. , Craik David J.
Published: October 2022

Human transthyretin (hTTR) can form amyloid deposits that accumulate in nerves and organs, disrupting cellular function. Molecules such as tafamidis that bind to and stabilize the TTR tetramer can reduce such amyloid formation. Here, we studied the interaction of VCP-6 (2-((3,5-dichlorophenyl)amino)benzoic acid) with hTTR. VCP-6 binds to hTTR with 5 times the affinity of the cognate ligand, thyroxine (T4). The structure of the hTTR:VCP-6 complex was determined by X-ray crystallography at 1.52 Å resolution. VCP-6 binds deeper in the binding channel than T4 with the 3′,5′-dichlorophenyl ring binding in the ‘forward’ mode towards the channel centre. The dichlorophenyl ring lies along the 2-fold axis coincident with the channel centre, while the 2-carboxylatephenylamine ring of VCP-6 is symmetrically displaced from the 2-fold axis, allowing the 2-carboxylate group to form a tight intermolecular hydrogen bond with Nζ of Lys15 and an intramolecular hydrogen bond with the amine of VCP-6, stabilizing its conformation and explaining the greater affinity of VCP-6 compared to T4. This arrangement maintains optimal halogen bonding interactions in the binding sites, via chlorine atoms rather than iodine of the thyroid hormone, thereby explaining why the dichloro substitution pattern is a stronger binder than either the diiodo or dibromo analogues.
Characterization and Optimization of Polymeric Bispicolamine Chelating Resin: Performance Evaluation via RSM Using Copper in Acid Liquors as a Model Substrate through Ion Exchange Method
Authors: Suwannahong Kowit , Sirilamduan Chadrudee , Deepatana Anat , Kreetachat Torpong , Wongcharee Surachai
Published: October 2022

Advanced technologies of electronics industries have led to environmental contamination concerns, especially waste print circuit boards containing a very high concentration of copper (II) ions, which can be discharged in wastewater containing many contaminated metals. A low pH is a necessity for treating industrial wastewater containing heavy metals to meet engineering process design. A novel polymeric bispicolamine chelating resin, Dowex-M4195, was applied as an alternative for investigating the behavior of copper (II) in acidic solution via an ion exchange method in a batch experiment system. Characterization of physical and chemical properties before and after ion exchange were also explored through BET, SEM-EDX, FTIR and XRD. Response surface methodology was also applied for optimization of copper (II) removal capacity using design of experiment for selective chelating resin at a low pH. The results indicate that H+ Dowex-M4195 chelating resin had a high-carbon content and specific surface area of >64% and 26.5060 m2/g, respectively. It was predominantly macropore porous in nature due to the N2 gas adsorption isotherm and exhibited type IV with insignificant desorption hysteresis loop of H1-type. It was spherical and cylindrical. After the ion exchange process of copper (II)-loaded H+ Dowex-M4195, the specific surface area and total pore volume decreased by about 17.82% and 5.39%, respectively, as compared to H+ Dowex-M4195. Hysteresis loop, isotherm and pore size distribution were also similar. Regarding the functional group, the surface morphology and crystalline structures of H+ Dowex-M4195 showed copper (II) compound based on the structure of chelating resin that confirmed effective ion exchange behavior. The design of optimization indicated that copper (II) removal capacity of about 31.33 mg/g was achieved, which could be obtained at 6.96 h, pH of 2 (a desirable low pH), dose of 124.13 mg and concentration of 525.15 mg/L. The study indicated that the H+ Dowex-M4195 (which is commercially available on the market) can successfully be applied as an alternative precursor through the ion exchange method for further reuse and regeneration of the copper (II) in the electronic waste industries and other wastewater applications needed to respond the policy of biocircular green economy in Thailand.
[99mTc]Tc-PSMA-T4—Novel SPECT Tracer for Metastatic PCa: From Bench to Clinic
Authors: Maurin Michał , Wyczółkowska Monika , Sawicka Agnieszka , Sikora Arkadiusz Eugeniusz , Karczmarczyk Urszula , Janota Barbara , Radzik Marcin , Kłudkiewicz Dominik , Pijarowska-Kruszyna Justyna , Jaroń Antoni , Wojdowska Wioletta , Garnuszek Piotr
Published: October 2022

Despite significant advances in nuclear medicine for diagnosing and treating prostate cancer (PCa), research into new ligands with increasingly better biological properties is still ongoing. Prostate-specific membrane antigen (PSMA) ligands show great potential as radioisotope carriers for the diagnosis and therapy of patients with metastatic PCa. PSMA is expressed in most types of prostate cancer, and its expression is increased in poorly differentiated, metastatic, and hormone-refractory cancers; therefore, it may be a valuable target for the development of radiopharmaceuticals and radioligands, such as urea PSMA inhibitors, for the precise diagnosis, staging, and treatment of prostate cancer. Four developed PSMA-HYNIC inhibitors for technetium-99m labeling and subsequent diagnosis were subjected to preclinical in vitro and in vivo studies to evaluate and compare their diagnostic properties. Among the studied compounds, the PSMA-T4 (Glu-CO-Lys-L-Trp-4-Amc-HYNIC) inhibitor showed the best biological properties for the diagnosis of PCa metastases. [99mTc]Tc-PSMA-T4 also showed effectiveness in single-photon emission computed tomography (SPECT) studies in humans, and soon, its usefulness will be extensively evaluated in phase 2/3 clinical trials.
Synthesis of Novel Diketopyrrolopyrrole-Rhodamine Conjugates and Their Ability for Sensing Cu2+ and Li+
Authors: Queirós Carla , Almodôvar Vítor A. S. , Martins Fábio , Leite Andreia , Tomé Augusto C. , Silva Ana M. G.
Published: October 2022

The search for accurate and sensitive methods to detect chemical substances, namely cations and anions, is urgent and widely sought due to the enormous impact that some of these chemical species have on human health and on the environment. Here, we present a new platform for the efficient sensing of Cu2+ and Li+ cations. For this purpose, two novel photoactive diketopyrrolopyrrole-rhodamine conjugates were synthesized through the condensation of a diketopyrrolopyrrole dicarbaldehyde with rhodamine B hydrazide. The resulting chemosensors 1 and 2, bearing one or two rhodamine hydrazide moieties, respectively, were characterized by 1H and 13C NMR and high-resolution mass spectrometry, and their photophysical and ion-responsive behaviours were investigated via absorption and fluorescence measurements. Chemosensors 1 and 2 displayed a rapid colorimetric response upon the addition of Cu2+, with a remarkable increase in the absorbance and fluorescence intensities. The addition of other metal ions caused no significant effects. Moreover, the resulting chemosensor-Cu2+ complexes revealed to be good probes for the sensing of Li+ with reversibility and low detection limits. The recognition ability of the new chemosensors was investigated by absorption and fluorescence titrations and competitive studies.
Challenges in the Heterologous Production of Furanocoumarins in Escherichia coli
Authors: Rodrigues Joana L. , Gomes Daniela , Rodrigues Lígia R.
Published: October 2022

Coumarins and furanocoumarins are plant secondary metabolites with known biological activities. As they are present in low amounts in plants, their heterologous production emerged as a more sustainable and efficient approach to plant extraction. Although coumarins biosynthesis has been positively established, furanocoumarin biosynthesis has been far more challenging. This study aims to evaluate if Escherichia coli could be a suitable host for furanocoumarin biosynthesis. The biosynthetic pathway for coumarins biosynthesis in E. coli was effectively constructed, leading to the production of umbelliferone, esculetin and scopoletin (128.7, 17.6, and 15.7 µM, respectively, from tyrosine). However, it was not possible to complete the pathway with the enzymes that ultimately lead to furanocoumarins production. Prenyltransferase, psoralen synthase, and marmesin synthase did not show any activity when expressed in E. coli. Several strategies were tested to improve the enzymes solubility and activity with no success, including removing potential N-terminal transit peptides and expression of cytochrome P450 reductases, chaperones and/or enzymes to increase dimethylallylpyrophosphate availability. Considering the results herein obtained, E. coli does not seem to be an appropriate host to express these enzymes. However, new alternative microbial enzymes may be a suitable option for reconstituting the furanocoumarins pathway in E. coli. Nevertheless, until further microbial enzymes are identified, Saccharomyces cerevisiae may be considered a preferred host as it has already been proven to successfully express some of these plant enzymes.
Recent Research Progress on Natural Stilbenes in Dendrobium Species
Authors: Zhai Denghui , Lv Xiaofa , Chen Jingmei , Peng Minwen , Cai Jinyan
Published: October 2022

Dendrobium is the second biggest genus in the Orchidaceae family, and many of them have been utilized as a traditional Chinese medicine (TCM) for thousands of years in China. In the last few decades, constituents with great chemical diversity were isolated from Dendrobium, and a wide range of biological activities were detected, either for crude extracts or for pure compounds. Stilbene compound is one of the primary active constituents in the genus Dendrobium. At present, 267 stilbene compounds with clarified molecular structures have been extracted and isolated from 52 species of Dendrobium, including 124 phenanthrenes and 143 bibenzyls. At the same time, activity studies have indicated that 157 compounds have pharmaceutical activity. Among them, most of the compounds showed antitumor activity, followed by antioxidant, anti-inflammatory and anti-α-glucosidase inhibitory activities. Additionally, 54 compounds have multiple pharmacological activities, such as confusarin (14), 2,4,7-trihydroxy-9,10-dihydro-phenanthrene (43), moscatilin (148), gigantol (150) and batatasin III (151). This review summarizes current knowledge about the chemical composition of stilbene, bioactivities and pharmacologic effects in 52 species of Dendrobium. We also expect to provide a reference for further research, development and utilization of stilbene constituents in the Dendrobium genus.
Acid Catalyzed Stereocontrolled Ferrier-Type Glycosylation Assisted by Perfluorinated Solvent
Authors: Lu Zhiqiang , Li Yanzhi , Xiang Shaohua , Zuo Mengke , Sun Yangxing , Jiang Xingxing , Jiao Rongkai , Wang Yinghong , Fu Yuqin
Published: October 2022

Described herein is the first application of perfluorinated solvent in the stereoselective formation of O-/S-glycosidic linkages that occurs via a Ferrier rearrangement of acetylated glycals. In this system, the weak interactions between perfluoro-n-hexane and substrates could augment the reactivity and stereocontrol. The initiation of transformation requires only an extremely low loading of resin-H+ and the mild conditions enable the accommodation of a broad spectrum of glycal donors and acceptors. The ‘green’ feature of this chemistry is demonstrated by low toxicity and easy recovery of the medium, as well as operational simplicity in product isolation.
A Hydroxytricyanopyrrole-Based Fluorescent Probe for Sensitive and Selective Detection of Hypochlorous Acid
Authors: Zeng Chunhua , Chen Zhengjun , Yang Mingyan , Lv Jiajia , Li Hongyu , Gao Jie , Yuan Zeli
Published: October 2022

Hypochlorous acid (HOCl) is a reactive substance that reacts with most biomolecules and is essential in physiological and pathological processes. Abnormally elevated HOCl levels may cause inflammation and other disease responses. To further understand its key role in inflammation, HOCl must be detected in situ. Here, we designed a hydroxytricyanopyrrole-based small-molecule fluorescent probe (HTCP-NTC) to monitor and identify trace amounts of HOCl in biological systems. In the presence of HOCl, HTCP-NTC released hydroxyl groups that emit strong fluorescence covering a wide wavelength range from the visible to near-infrared region owing to the resumption of the intramolecular charge transfer process. Additionally, HTCP-NTC demonstrated a 202-fold fluorescence enhancement accompanied by a large Stokes shift and a low detection limit (21.7 nM). Furthermore, HTCP-NTC provided a rapid response to HOCl within 18 s, allowing real-time monitoring of intracellular HOCl. HTCP-NTC exhibited rapid kinetics and biocompatibility, allowing effective monitoring of the exogenous and endogenous HOCl fluctuations in living cells. Finally, based on fluorescence imaging, HTCP-NTC is a potential method for understanding the relationship between inflammation and HOCl.
Effects of Maillard Reaction on Volatile Compounds and Antioxidant Capacity of Cat Food Attractant
Authors: Sun Kekui , Dai Zhaoqi , Hong Wenlong , Zhao Jianying , Zhao Hang , Luo Ji , Xie Guangjie
Published: October 2022

In this study, self-made cat food attractant was prepared by Maillard reaction using hydrolysate of grass carp waste as raw material and glucose and cysteine hydrochloride as substrate. Its volatile compounds, antioxidant capacity, and pet palatability were investigated. The volatile compounds of attractants were analyzed using gas chromatography–mass spectrometry (GC-MS) which showed that alcohols and aldehydes were the most volatile in self-made attractants, accounting for 34.29% and 33.52%, respectively. Furthermore, Maillard reaction could significantly increase the antioxidant activity of self-made attractant, including scavenging activity on OH and DPPH free radicals as well as the chelating ability of Fe2+. The acceptance and palatability of two kinds of cat food were studied by adding 3% self-made or commercial attractants. The results of this study also found that both attractants could remarkably improve the intake rate of cat food. However, the self-made group was significantly less than the commercial group in first smell, first bite, and feeding rate, which might be because of the absence of umami ingredients and spices in self-made attractants.
Chemical Composition of Tagetes patula Flowers Essential Oil and Hepato-Therapeutic Effect against Carbon Tetrachloride-Induced Toxicity (In-Vivo)
Authors: Aati Hanan Y. , Emam Mahmoud , Al-Qahtani Jawaher , Aati Sultan , Aati Abdulrahman , Wanner Juergen , Seif Mohamed M.
Published: October 2022

The liver is a crucial organ among body organs due to its wide functions, in particular, detoxification and metabolism. Exposure to detrimental chemicals or viral infections may provoke liver dysfunction and ultimately induce liver tissue damage. Finding natural substances for liver disease treatment to overcome the conventional treatments’ side effects has attracted the attention of researchers worldwide. Our current work was conducted to investigate the hepato-therapeutic activities of essential oil (EO) isolated from Tagetes patula flowers. EO was extracted using the hydro-distillation (HD) technique and its chemical composition was identified by GC/MS. Then, the hepatic treatment potential of extracted EO was evaluated in vivo against CCL4 in rats. HD of T. patula flowers yielded highly chemical constituents of EO along with significant antioxidant potential. A coherent molecular network was fashioned via the Global Natural Products Social Molecular Networking (GNPS) to visualize the essential components and revealed that the sesquiterpene (E)-β-caryophyllene was the most predominant volatile constituent which accounted for 24.1%. The treatment of CCL4 led to significant induced oxidative stress markers malonaldehyde, total protein, and non-protein sulfhydryl, as well as elevated serum aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, and bilirubin. In addition, it disrupted the level of lipid profile. The post-treatment using T. patula EO succeeded in relieving all toxic effects of CCl4 and recuperating the histopathological signs induced by CCL4. Silymarin was used as a standard hepatoprotective agent. The obtained results demonstrated that the extracted EO exerted high protective activities against the toxicity of CCL4. Moreover, the T. patula flowers EO can be used as a natural remedy to relieve many contemporary liver diseases related to oxidative stress.
Methods of the Dehydration Process and Its Effect on the Physicochemical Properties of Stingless Bee Honey: A Review
Authors: Ikhsan Liyana Nabihah , Chin Kok-Yong , Ahmad Fairus
Published: October 2022

Stingless bee honey (SLBH) has a high moisture content, making it more prone to fermentation and leading to honey spoilage. Dehydration of SLBH after harvest is needed to reduce the moisture content. This review compiles the available data on the dehydration methods for SLBH and their effect on its physicochemical properties. This review discovered the dehydration process of vacuum drying at 60 °C and 5% moisture setting, freeze-drying at −54 °C and 5% moisture setting for 24 h, and using a food dehydrator at 55 °C for 18 h could extract >80% water content in SLBH. As a result, these methods could decrease moisture content to <17% and water activity to <0.6. These will prevent the fermentation process and microorganism growth. The hydroxymethylfurfural (HMF) contents remain within the permissible standard of <40 mg/kg. The total phenolic content increased after dehydration by these methods. Therefore, dehydration of SLBH is recommended to increase its benefits.
Multifunctional Derivatives of Spiropyrrolidine Tethered Indeno-Quinoxaline Heterocyclic Hybrids as Potent Antimicrobial, Antioxidant and Antidiabetic Agents: Design, Synthesis, In Vitro and In Silico Approaches
Authors: Bouali Nouha , Hammouda Manel Ben , Ahmad Iqrar , Ghannay Siwar , Thouri Amira , Dbeibia Amal , Patel Harun , Hamadou Walid Sabri , Hosni Karim , Snoussi Mejdi , Adnan Mohd , Hassan Md Imtaiyaz , Noumi Emira , Aouadi Kaïss , Kadri Adel
Published: October 2022

To combat emerging antimicrobial-resistant microbes, there is an urgent need to develop new antimicrobials with better therapeutic profiles. For this, a series of 13 new spiropyrrolidine derivatives were designed, synthesized, characterized and evaluated for their in vitro antimicrobial, antioxidant and antidiabetic potential. Antimicrobial results revealed that the designed compounds displayed good activity against clinical isolated strains, with 5d being the most potent (MIC 3.95 mM against Staphylococcus aureus ATCC 25923) compared to tetracycline (MIC 576.01 mM). The antioxidant activity was assessed by trapping DPPH, ABTS and FRAP assays. The results suggest remarkable antioxidant potential of all synthesized compounds, particularly 5c, exhibiting the strongest activity with IC50 of 3.26 ± 0.32 mM (DPPH), 7.03 ± 0.07 mM (ABTS) and 3.69 ± 0.72 mM (FRAP). Tested for their α-amylase inhibitory effect, the examined analogues display a variable degree of α-amylase activity with IC50 ranging between 0.55 ± 0.38 mM and 2.19 ± 0.23 mM compared to acarbose (IC50 1.19 ± 0.02 mM), with the most active compounds being 5d, followed by 5c and 5j, affording IC50 of 0.55 ± 0.38 mM, 0.92 ± 0.10 mM, and 0.95 ± 0.14 mM, respectively. Preliminary structure–activity relationships revealed the importance of such substituents in enhancing the activity. Furthermore, the ADME screening test was applied to optimize the physicochemical properties and determine their drug-like characteristics. Binding interactions and stability between ligands and active residues of the investigated enzymes were confirmed through molecular docking and dynamic simulation study. These findings provided guidance for further developing leading new spiropyrrolidine scaffolds with improved dual antimicrobial and antidiabetic activities.