Low temperature soldering technology based on superhydrophobic copper microlayer.

Cu-Cu soldering is realized under certain pressure and low temperature conditions by using a surface silver film to modify the copper microlayer structure, thus solving the problems of high thermal stress and signal delay aggravation caused by high temperature in the traditional reflow soldering process. The copper microlayer modified with silver film is obtained by electrodeposition. The surface substructure of the Cu microlayer is a nano cone-shaped protrusion. The diameter of the bottom of the cone is 500 nm∼1 µm, and the height of the cone is 1∼2 µm. The thickness of the silver film is about 320 nm, and the modification of the copper layer with silver film can effectively prevent the oxidation of the copper layer. Two silver-modified copper microlayers are placed in face-to-face contact as a soldering couple. A certain pressure and low temperature are applied to the contact area to realize the soldering and interconnection. The morphology of the soldered interface and the average shear strength of the soldered joints are analyzed by scanning electron microscopy, transmission electron microscopy and solder joint tester. It is found that under the optimal soldering parameters of soldering temperature 220 °C, soldering pressure 20 MPa and soldering time 20 min, the nano-conical projections of the Cu micrometer layer are inserted into each other to produce a physical blocking effect. The highly surface-meltable silver film effectively connects the surrounding copper layer as an intermediate buffer layer. The average shear strength of soldering joints is significantly increased. Heat treatment experiments have shown that the average shear strength can be effectively increased by heat treatment for an appropriate period of time. Prolonged exposure to heat has little effect on the average shear strength. With the special morphology of the copper microlayer structure and the nano-size effect of the silver layer, soldering can be done at low temperatures. The quality of the soldering interface is good and small soldering dimensions can be obtained.

"Active carbon" is more advantageous to the bacterial community in the rice rhizosphere than "stable carbon".

Carbon materials are commonly used for soil carbon sequestration and fertilization, which can also affect crop growth by manipulating the rhizosphere bacterial community. However, the comparison of the differences between active carbon (e.g., organic fertilizers) and stable carbon (e.g., biochar) on rhizosphere microdomains is still unclear. Hence, a trial was implemented to explore the influence of control (CK, no fertilizer; NPK, chemical fertilizer), organic fertilizer (CF-O, organic fertilizer; CF-BO, biochar-based organic fertilizer) and biochar material (CF-B, perishable garbage biochar; CF-PMB, pig manure biochar) on the diversity, composition, and interaction of rice rhizosphere bacterial community through 16 S rRNA gene high-throughput sequencing. Our results demonstrate that organic fertilizer increases bacterial alpha-diversity compared to no-carbon supply treatment to the extend, whereas biochar has the opposite effect. The rhizosphere bacterial community composition showed pronounced variations among the various fertilization treatments. The relative abundance in Firmicutes decreased with organic fertilizer application, whereas that in Chloroflexi and Actinobacteria decreased with biochar application. Bacterial network analysis demonstrate that organic fertilizer enhances the complexity and key taxa of bacterial interactions, while biochar exhibits an opposing trend. The findings of our study indicate that organic fertilizer may contribute to a positive and advantageous impact on bacterial diversity and interaction in rice rhizosphere, whereas the influence of biochar is not as favorable and constructive. This study lays the foundation for elucidating the fate of the rhizosphere bacterial community following different carbon material inputs in the context of sustainable agricultural development.

Targeted therapy of kidney disease with nanoparticle drug delivery materials.

With the development of nanomedicine, nanomaterials have been widely used, offering specific drug delivery to target sites, minimal side effects, and significant therapeutic effects. The kidneys have filtration and reabsorption functions, with various potential target cell types and a complex structural environment, making the strategies for kidney function protection and recovery after injury complex. This also lays the foundation for the application of nanomedicine in kidney diseases. Currently, evidence in preclinical and clinical settings supports the feasibility of targeted therapy for kidney diseases using drug delivery based on nanomaterials. The prerequisite for nanomedicine in treating kidney diseases is the use of carriers with good biocompatibility, including nanoparticles, hydrogels, liposomes, micelles, dendrimer polymers, adenoviruses, lysozymes, and elastin-like polypeptides. These carriers have precise renal uptake, longer half-life, and targeted organ distribution, protecting and improving the efficacy of the drugs they carry. Additionally, attention should also be paid to the toxicity and solubility of the carriers. While the carriers mentioned above have been used in preclinical studies for targeted therapy of kidney diseases both in vivo and in vitro, extensive clinical trials are still needed to ensure the short-term and long-term effects of nano drugs in the human body. This review will discuss the advantages and limitations of nanoscale drug carrier materials in treating kidney diseases, provide a more comprehensive catalog of nanocarrier materials, and offer prospects for their drug-loading efficacy and clinical applications.

Simultaneous detection of the shuttling motion of liquid metal droplets in channels under alternating pressure and capacitive sensor signals.

Implementing a signal-switching mechanism for the selective use of integrated sensors and actuators plays a crucial role in streamlining the functionality of miniaturized devices. Here, a liquid metal droplet (LMD)-based signal-switching mechanism is introduced to achieve such functionality. Pressure modulation with a 100-µm spatial resolution enabled precise control of the position of the LMDs within a channel. After integrating the channel with asymmetrically structured electrodes, the effect of the shuttle-like movement of LMD on the temporal changes in the overall capacitance was investigated. Consequently, analysis of the capacitive peaks revealed the directional movement of the LMDs, enabling estimation of the position of the LMDs without direct observation. In addition, we achieved successful signal extraction from the capacitive sensor that was linked to the activated electrodes, thereby enabling selective data retrieval. The proposed signal-switching mechanism method achieved a detection accuracy of ~0.1 pF. The sensor's ability to simultaneously detect the LMD position and generate a signal underscores its significant potential for multiplexing in multisensing systems, particularly in concealed environments, such as in vivo settings.

Compressive strength ratios of concretes containing pozzolans under elevated temperatures.

Cement production is one of the major pollution contributors owing to its large rates of energy consumption and gas emission. Moreover, high temperatures could detrimentally impact the concrete infrastructure and thus, it would be essential to study performance of such structures under exposure to the elevated temperatures. In this paper, post-heat performance of the concrete whose cement has been added by zeolite and bentonite at ratios of 6 and 10% (by cement weight) under exposure to temperatures of 28, 150, 300 and 700 °C, was studied. Based on the results, replacing cement by zeolite and bentonite at the age of 90 days under ambient temperature, increases the compressive strength compared to the control specimen. Moreover, it was observed that heating the cubic and cylindrical specimens containing 10% bentonite at 150 °C, increase the compressive strength by 40%. Conversely, the results indicate that when exposed to temperatures of 300 and 700 °C, a decreasing trend is seen in the tensile strength of both cubic and cylindrical specimens containing the pozzolans. Peak intensity of C-S-H has dropped as per rise in temperature from 28 to 700 °C. These values reveal that peak intensity of C-S-H up to 300 °C, is approximately the same but under 700 °C, it has reduced considerably. In all the cubic and cylindrical specimens, it can be seen that the specimens heated at 150° have the highest compressive strength and the specimens heated at 700 °C have the lowest compressive strength compared to the same unheated specimens. The XRD patterns at 150 and 300 °C, reveal decrease and increase in the Portlandite content the difference between conversion ratio of the cubic and cylindrical specimens in this study, to the values provided by the codes, is less than 10%.

Binder assisted graphene derivatives as lubricants in copper: Improved tribological performance for industrial application.

Originally derived from graphite, high-quality single-layer graphene is an excellent anti-wear and -friction additive in metal matrix. Here, the tribological performance of 3 different commercialized graphene derivatives (e.g., graphene oxide [GO], reduced graphene oxide [RGO], and graphene nanoplatelet [GNP]) as additives in a Cu matrix, were investigated from an industrial perspective. To increase the interaction of graphene derivatives with Cu particles, and addressing the aggregation problem of the graphene derivatives, different binders (polyvinyl alcohol [PVA] and cellulose nanocrystals [CNC]) were introduced into the system. Benefiting from such a strategy, a uniform distribution of the graphene derivatives in Cu matrix was achieved with graphene loading up to 5 wt %. After high-temperature sintering, the graphene is preserved and well distributed in the Cu matrix. It was found that the GNP-containing sample shows the most stable friction coefficient behavior. However, GO and RGO also improve the tribological performance of Cu under different circumstances.

Effect of Thermo- and pH-sensitive Block Copolymer Structure and Composition on the Synthesis and Stabilization of Gold Nanoparticles.

Homopolymers of poly[N-(2-(diethylamino)ethyl) acrylamide] exhibit the ability to adsorb onto the surface of preformed or growing gold nanoparticles. The resulting hybrid materials possess a pH and thermo-sensitive nature. Consequently, their optical properties can be modulated by manipulating either the temperature or the pH. Moreover, introducing monomers based on poly(N-isopropyl acrylamide) into block or random statistical polymers enables further modulation of the thermosensitive properties. These copolymers, employed for the in-situ synthesis and/or stabilization of gold nanoparticles, lead to hybrid materials whose properties and/or particle size depend on the polymer composition and microstructure: statistical polymers emerge as superior stabilizing agents compared to their block counterparts at a constant composition.

Brightness Strategies toward NIR-II Emissive Conjugated Materials: Molecular Design, Application, and Future Prospects.

Recent advances have been made in second near-infrared (NIR-II) fluorescence bioimaging and many related applications because of its advantages of deep penetration, high resolution, minimal invasiveness, and good dynamic visualization. To achieve high-performance NIR-II fluorescence bioimaging, various materials and probes with bright NIR-II emission have been extensively explored in the past few years. Among these NIR-II emissive materials, conjugated polymers and conjugated small molecules have attracted wide interest due to their native biosafety and tunable optical performance. This review summarizes the brightness strategies available for NIR-II emissive conjugated materials and highlights the recent developments in NIR-II fluorescence bioimaging. A concise, detailed overview of the molecular design and regulatory approaches is provided in terms of their high brightness, long wavelengths, and superior imaging performance. Then, various typical cases in which bright conjugated materials are used as NIR-II probes are introduced by providing step-by-step examples. Finally, the current problems and challenges associated with accessing NIR-II emissive conjugated materials for bright NIR-II fluorescence bioimaging are briefly discussed, and the significance and future prospects of these materials are proposed to offer helpful guidance for the development of NIR-II emissive materials.

Resonant Raman Scattering Study of Strain and Defects in Chemical Vapor Deposition Grown MoS2 Monolayers.

The development of bottom-up synthesis routes for semiconducting transition metal dichalcogenides (TMDs) and the assessment of their defects are of paramount importance to achieve their applications. TMD monolayers grown by chemical vapor deposition (CVD) can be subjected to significant strain and, here, Raman and photoluminescence spectroscopies are combined to characterize strain in over one hundred MoS2 monolayer samples grown by CVD. The frequency changes of phonons as a function of strain are analyzed, and used to extract the Grüneisen parameter of both zone-center and edge phonons. Additionally, the intensity of the defect-induced longitudinal acoustic (LA) and transverse acoustic (TA) Raman bands are discussed in relation to strain and electronic doping. The experimental mode-Grüneisen parameters obtained are compared with those calculated by density functional theory (DFT), to better characterize the type of strain and its resulting effects on Grüneisen parameters. The findings indicate that the use of Raman spectra to determine defect densities in 2D MoS2 must be always conducted considering strain effects. To the best of the authors' knowledge, this work constitutes the first report on double resonance Raman processes studied as a function of strain in 2D-MoS2. The new approach to obtain the Grüneisen parameter from zone-edge phonons in MoS2 can also be extended to other 2D semiconducting TMDs.

Investigation of second-order NLO properties of novel 1,3,4-oxadiazole derivatives: a DFT study.

CONTEXT: In this study, we have developed four new chromophores (TM1-TM4) and performed quantum chemical calculations to explore their nonlinear optical properties. Our focus was on understanding the impact of electron-donating substituents on 1,3,4-oxadiazole derivative chromophores. The natural bond orbital analysis confirmed the interactions between donors and acceptors as well as provided insights into intramolecular charge transfer. We also estimated dipole moment, linear polarizability molecular electrostatic potential, UV-visible spectra, and first hyperpolarizability. Our results revealed that TM1 with a strong and stable electron-donating group exhibited high first hyperpolarizability (ß) 293,679.0178 × 10-34 esu. Additionally, TM1 exhibited a dipolar moment (µ) of 5.66 Debye and polarizability (α) of 110.62 × 10-24 esu when measured in dimethyl sulfoxide (DMSO) solvent. Furthermore, in a benzene solvent, TM1 showed a low energy band gap of 5.33 eV by using the ωB97XD functional with a 6-311 + + G(d, p) basis set. Moreover, our study of intramolecular charge transfers highlighted N, N dimethyl triphenylamine and carbazole as major electron-donating groups among the four 1,3,4-oxadiazole derivative chromophores. This research illustrates the potential applications of these organic molecules in photonics due to their versatile nature. METHODS: The molecules were individually optimized using different functionals, including APFD, B3LYP, CAM B3LYP, and ωB97XD combined with the 6-311 + + G (d, p) basis set in Gaussian 16 software. These methods encompass long-range functionals such as APFD and B3LYP, along with long-range corrected functionals like CAM B3LYP and ωB97XD. The employed functionals of APFD, B3LYP, CAM B3LYP, and ωB97XD with the 6-311 + + G (d,p) basis set were used to extract various properties such as geometrical structures, dipole moment, molecular electrostatic potential, and first hyperpolarizability through precise density functional theory (DFT). Additionally, TD-DFT was utilized for obtaining UV-visible spectra. All studies have been conducted in both gas and solvent phases.

Research on Chinese medicinal materials cultivation: A bibliometric and visual analysis.

Chinese medicinal materials (CMMs) are important strategic resource in China. The cultivation process of medicinal plants is the key link which directly affect the quality and efficacy. The literatures of CMMs cultivation were acquired from China National Knowledge Infrastructure (CNKI) database and State Intellectual Property Office (SIPO) patent database for the years between 2001 and 2021. All the articles found were subjected to bibliometric analysis. The development trends and key topics were analyzed and visualized by VOSviewer and CiteSpace software. The results indicate that ecological planting, under-forest economy, intercropping patterns and industrialization production are the research hotspots in this field; cultivation technology and nutritional fertilization technology are the main areas addressed in recent years. Therefore, the high-quality and sustainable development of CMMs cultivation should be examined in terms of theoretical approaches, technical innovation, multi-cooperation, and intellectual property protection.

Comparison of the Antibacterial Effect of AH26, Adseal and Beta RCS Root Canal Sealers against Enterococcus Faecalis, an in Vitro Study.

Objectives: Antibacterial activity against endodontic pathogens is a desirable feature for root canal sealers. The objective of this study was to compare the antibacterial effect of three resin-based endodontic sealers (AH26, Adseal, and Beta RCS) against Enterococcus faecalis in vitro. Materials and Methods: The antibacterial properties of the sealers were assessed against E. faecalis using agar diffusion test (ADT) for fresh state (N=10) and direct contact test (DCT) for freshly-mixed and set states of the materials (N=10). In ADT, the diameter of the zones of inhibition was measured after 24h of contact. In DCT, the colony-forming units of the bacteria were counted after 30 minutes and 180 minutes of exposure. The results were analyzed with two-way ANOVA and independent sample t-test. P<0.05 was considered significant. Results: Regarding DCT results, all test materials indicated an antibacterial effect, both in freshly-mixed and set states. The highest antibacterial effect was related to Adseal, whereas the lowest was observed in Beta RCS. There was a significant difference between all study groups (different sealers, setting states, and contact times; P<0.001), except for freshly-mixed AH26 and Adseal at 180 minutes (P>0.05). According to ADT, AH26 and Adseal represented the widest and the smallest inhibition zones, respectively (P<0.001). Conclusion: Within the limitations of this in vitro study, AH26, Adseal, and Beta RCS showed antibacterial effects against E. faecalis in both freshly-mixed and set states. The antibacterial effect increased over time in all of the studied sealers.

Adaptive plasticity of auxetic Kirigami hydrogel fabricated from anisotropic swelling of cellulose nanofiber film.

Hydrogels are flexible materials that typically accommodate elongation with positive Poisson's ratios. Auxetic property, i.e., the negative Poisson's ratio, of elastic materials can be macroscopically implemented by the structural design of the continuum. We realize it without mold for hydrogel made of cellulose nanofibers (CNFs). The complex structural design of auxetic Kirigami is first implemented on the dry CNF film, i.e., so-called nanopaper, by laser processing, and the CNF hydrogel is formed by dipping the film in liquid water. The CNF films show anisotropic swelling where drastic volumetric change mainly originates from increase in the thickness. This anisotropy makes the design and fabrication of the emergent Kirigami hydrogel straightforward. We characterize the flexibility of this mechanical metamaterial made of hydrogel by cyclic tensile loading starting from the initial end-to-end distance of dry sample. The tensile load at the maximum strain decreases with the increasing number of cycles. Furthermore, the necessary work up to the maximum strain even decreases to the negative value, while the work of restoration to the original end-to-end distance increases from the negative value to the positive. The equilibrium strain where the force changes the sign increases to reach a plateau. This plastic deformation due to the cyclic loading can be regarded as the adaptive response without fracture to the applied dynamic loading input.

Highly anisotropic swelling-based gelation of dry film of cellulose nanofibers enables development of emergent hydrogel Kirigami with auxetic behavior. Furthermore, adaptive response to the iterative loading condition is found.

Amphiphilic Polyphosphazene for Fluorocarbon Emulsion Stabilization.

High internal phase emulsions (HIPEs) have been of great interest for fabricating fluorinated porous polymers having controlled pore structures and excellent physicochemical properties. However, it remains a challenge to prepare stable fluorocarbon HIPEs, due to the lack of suitable surfactants. By randomly grating hydrophilic and fluorophilic side chains to polyphosphazene (PPZ), a comb-like amphiphilic PPZ surfactant with biodegradability is designed and synthesized for stabilizing water/fluorocarbon oil-based emulsions. The hydrophilic-lipophilic balance of PPZs can be controlled by tuning the grating ratio of the two side chains, leading to the preparation of stable water-in-oil HIPEs and oil-in-water emulsions, and the production of fluorinated porous polymers and particles by polymerizing the oil phase. These fluorinated porous polymers show excellent thermal stability and, due to the hydrophobicity and porous structure, applications in the field of oil/water separation can be achieved.

Uncovering the recycling potential of industrial waste in Sri Lanka.

The generation of industrial waste is mainly dependent on several factors, including the type of industry, production capacity, technology use and raw materials involved in the manufacturing processes. The present study is a cross-sectional study that was conducted with 580 industries under six industrial sectors in Sri Lanka in 2022. The main objective of this research was to investigate solid waste generation and estimate the recyclable fraction in the waste. Furthermore, this study calculated the prevailing recycling rate of each industrial sector and the waste generation per person employed in the sector. Industrial processes, the types and quantities of waste, waste disposal methods and management activities in terms of recycling and disposal were evaluated through a structured questionnaire and random field observations. The study identified that the composition of selected recyclable items was 16.7% of the total waste generated in the industrial sector. The prevailing rate of recycling in different sectors was as follows: manufacturing of food products (36.6%), manufacturing of beverages (82.3%), manufacturing of textiles (68.6%), manufacturing of chemical and chemical products (28.5%), manufacturing of rubber and plastic (46.5%) and manufacturing of metallic mineral products (17.8%) from the total generated recyclable material. The study further estimated the waste intensity (waste generation per unit of product output) of the industrial sectors as follows: 0.38 (manufacturing of food products), 0.36 (manufacturing of beverages), 0.27 (manufacturing of textiles), 0.26 (manufacturing of chemical and chemical products), 0.17 (manufacturing of rubber and plastic) and 0.16 (manufacturing of non-metallic mineral products).

Recent Advances on Diarylethene-Based Photoswitching Materials: Applications in Bioimaging, Controlled Singlet Oxygen Generation for Photodynamic Therapy and Catalysis.

Diarylethenes (DAE), a class of best performing photoswitchable compounds, where the key features of stability, photoisomerization wavelengths, quantum yield and variability in the photoisomers significantly depend on their derivatization. The last decade has witnessed a surge in the engagement of DAEs to different areas of chemical and biological impacts like catalysis in synthetic organic chemistry, biological markers for in vivo imaging of live cells, chemosensing within cells to photo-dynamic therapy by controlled generation of singlet oxygen. Previous reviews on applications of DAE-based systems did not predominantly cover all the aspects of biological and industrial implementations. They have covered only one field of application either in the biological science or the synthetic aspect or photochromic aspects only. This review is a coalition of all those aspects in last six years. Here the variation of properties of the DAE systems with respect to structural diversifications have been discussed in detail along with their potential applications in catalysis, regulating singlet oxygen generation, photodynamic therapy, bioimaging and their future prospects. We hope that this review will certainly motivate researchers to generate new DAE architectures with superior bioimaging or catalyzing properties in future.

Regeneration of Volumetric Muscle Loss Using MSCs Encapsulated in PRP-Derived Fibrin Microbeads.

Volumetric muscle loss (VML) is one of the major types of soft tissue injury frequently encountered worldwide. In case of VML, the endogenous regenerative capacity of the skeletal muscle tissue is usually not sufficient for complete healing of the damaged area resulting in permanent functional musculoskeletal impairment. Therefore, the development of new tissue engineering approaches that will enable functional skeletal muscle regeneration by overcoming the limitations of current clinical treatments for VML injuries has become a critical goal. Platelet-rich plasma (PRP) is an inexpensive and relatively effective blood product with a high concentration of platelets containing various growth factors and cytokines involved in wound healing and tissue regeneration. Due to its autologous nature, PRP has been a safe and widely used treatment option for various wound types for many years. Recently, PRP-based biomaterials have emerged as a promising approach to promote muscle tissue regeneration upon injury. This chapter describes the use of PRP-derived fibrin microbeads as a versatile encapsulation matrix for the localized delivery of mesenchymal stem cells and growth factors to treat VML using tissue engineering strategies.

An Updated Review on Functionalized Graphene as Sensitive Materials in Sensing of Pesticides.

Numerous chemical pesticides were employed for a long time to manage pests, but their uncontrolled application harmed the health and the environment. Accurately quantifying pesticide residues is essential for risk evaluation and regulatory purposes. Numerous analytical methods have been developed and utilized to achieve sensitive and specific detection of pesticides in intricate samples like water, soil, food, and air. Electrochemical sensors based on amperometry, potentiometry, or impedance spectroscopy offer portable, rapid, and sensitive detection suitable for on-site analysis. This study examines the potential of electrochemical sensors for the accurate evaluation of various effects of pesticides. Emphasizing the use of Graphene (GR), Graphene Oxide (GO), Reduced Graphene Oxide (rGO), and Graphdiyne composites, the study highlights their enhanced performance in pesticide sensing by stating the account of many actual sensors that have been made for specific pesticides. Computational studies provide valuable insights into the adsorption kinetics, binding energies, and electronic properties of pesticide-graphene complexes, guiding the design and optimization of graphene-based sensors with improved performance. Furthermore, the discussion extends to the emerging field of biopesticides. While the GR/GO/rGO based sensors hold immense future prospects, their existing limitations have also been discussed, which need to be solved with future research.

Smart Material for Smarter Dentistry.

Smart materials encompass a variety of substances, including smart antimicrobial peptides, pit and fissure sealants, impression materials, cement, and sutures. These materials can change properties under specific stimuli such as temperature, stress, moisture, pH, or electric and magnetic fields. These constituents signify the commencement of a novel era or epoch in the field of smart dentistry and exhibit the potential for enhanced efficacy in the future.

Comparing the Efficacy of Different Archwire Materials in Accelerating Orthodontic Tooth Movement.

Background: Orthodontic treatment is commonly used to correct misaligned teeth and improve dental aesthetics and function. Archwires play a crucial role in this treatment by exerting forces on teeth, prompting them to shift into desired positions. Materials and Methods: For this experimental study, 60 participants requiring orthodontic treatment were selected and divided into three groups: Group A, treated with stainless steel archwires; Group B, treated with nickel-titanium archwires; and Group C, treated with beta-titanium archwires. Standardized orthodontic procedures were followed for all participants. The rate of tooth movement was measured over a period of 6 months using digital models and a calibrated measurement technique. Results: The study revealed notable differences in the rate of orthodontic tooth movement among the three groups. Group B (nickel-titanium archwires) demonstrated the highest mean rate of tooth movement, with an average of 1.5 mm per month. Group A (stainless steel archwires) exhibited a mean rate of 1.2 mm per month, while Group C (beta-titanium archwires) showed the lowest mean rate at 0.9 mm per month. Conclusion: In conclusion, this study highlights the varying efficacy of different archwire materials in accelerating orthodontic tooth movement. Nickel-titanium archwires exhibited the highest rate of tooth movement compared to stainless steel and beta-titanium archwires.