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Gold nanorods (Au NRs) have attracted extensive research interest due to their unique optical properties, adjustable aspect ratio, and easy surface modification in the fields of biosensing, bioimaging, and disease diagnosis and detection. In this review, we present a comprehensive review of various methods for preparing gold nanorods including hard template method, electrochemistry method, photochemistry method, seed-mediated growth method, secondary growth method, and amorphous seed method. The unique optical properties of the gold nanorods and its applications in biomedical, detection, catalysis, and information storage will also be discussed in detail.

Growth of Cu polyhedral structures with well-defined and controllable shapes faced tremendous synthetic challenges in colloid nanocrystal synthesis in the past few decades. In this article, we report a facile approach for the synthesis of Cu nanocrystals with systematic morphological evolution. Transitional truncated octahedral, edge- and corner-truncated octahedral, all-corner-truncated octahedral, and octahedral structures were obtained in a solution-based reduction reaction by precise tuning reaction time. Four distinct morphologies of nanocrystals have been characterized by SEM technique. The optical properties of these various morphologies of nanocrystals were also investigated, and it indicates that the SPR band shifts red while the shape of nanoparticles evolves from transitional truncated octahedral to octahedral, whose resonant bands are transferred from 590 nm to 620 nm.

The Ga0.25Zn4.67S5.08 catalysts were prepared by ultrasonic spray pyrolysis with thiourea as a precursor. The crystal structure, optical properties, specific surface area, chemical composition, surface morphology, and internal structure of the prepared samples were characterized by XRD, UV-Vis DRS, BET, XPS, SEM, and TEM, respectively. The disinfection performance and the main active species of the synthesized catalysts under visible light irradiation were investigated with E. coli K12. The study results indicate that Ga0.25Zn4.67S5.08 prepared at 400°C exhibited the best antibacterial performance with complete kill of E. coli K12 within 4 h. The antibacterial performance of the prepared sample is also higher than that prepared by the hydrothermal method. The result of the radical trapping experiment indicates that the photogenerated holes play a dominant role in the disinfection process.

In this paper, we synthesized ~105±15 nm cubic phase KMnF3:Yb3+,Er3+ NPs, ~195±10 nm hexagonal phase NaYF4:Yb3+,Tm3+ NPs, and ~200±10 nm hexagonal phase NaYF4:Yb3+,Er3+ NPs. Under the excitation of 980 nm, the strong red upconversion luminescence (4F9/2⟶4I15/2, the peak is located at ~653 nm) of Er3+ ions of KMnF3:Yb3+,Er3+ NPs can be seen, the strong blue upconversion luminescence (1D2⟶3F4, 1G4⟶3H6; the peaks are located at ~451 nm and ~477 nm, respectively) of Tm3+ ions of NaYF4:Yb3+,Tm3+ NPs can be observed, and the strong green upconversion luminescence (4I11/2⟶4I15/2, 4S3/2⟶4I15/2; the peaks are located at ~524 nm and ~541 nm, respectively) of Er3+ ions of NaYF4:Yb3+,Er3+ NPs can be found. The mixed white upconversion luminescent materials can be obtained by adjusting the doping ratio of the above NPs. Cyclohexane solution of red, blue, green, and the mixed white NPs can be used as ink, and “JLNU” is written on paper with a pen. Without 980 nm radiation, nothing could be seen. Under 980 nm irradiation, the colored letters “JLNU” can be seen. Red, blue, green, and the mixed white upconversion NPs can be used in security anticounterfeiting.

Cancer was ranked as the second leading cause of death, and colon cancer has been reported as the third most frequent cancer worldwide. Chemotherapeutic drugs act on normal and cancerous cells similarly; therefore, they have various adverse side effects. Nanoparticles were identified to have a controlled effect on different cancer cell lines. The present study is aimed at studying biosynthesis silver nanoparticles by using aqueous Olea chrysophylla and Lavandula dentata leaf extracts, separately, and evaluating their anticancer potential. Silver nanoparticles were characterized by using SEM, XRD, FTIR, zeta potential, and size distribution mean, and their antiproliferative and apoptotic potentials were evaluated on HCT116 cells. Results show the formation of silver nanoparticles Olea-AgNPs and Lav-AgNPs due to the change of color to dark brown, and characterization revealed their crystalline shape with a mean size of 284.5 nm for Lav-AgNPs and 328.6 nm for Olea-AgNPs. Lav-AgNPs shows more stability than Olea-AgNPs due to its higher negative zeta potential (-14.3 mV) than nanoparticles biosynthesized from Olea leaves (-0.877 mV). Conversely, Lav-AgNPs shows more effective antiproliferative potential on HCT116 with (IC50 = 59.79 μg/ml) than Olea-AgNPs (IC50 = 99.35 μg/ml). However, Olea-AgNPs significantly increased the late stage of apoptotic and necrotic cells in comparison to Lav-AgNPs-treated cells in flow cytometry assay. Silver nanoparticles biosynthesized from Olea and lavender show anticancer potential with a more effective potential reported compared to Lav-AgNPs.

The simple and practicable intrinsic driving mechanism is of great significance for the design and development of nanoscale devices. This paper proposes a nanosystem that can achieve directional gradientless thermoexcited rotation at a relatively high temperature field (such as 300 K). In the case of a constant temperature field, the difference in atomic van der Waals (VDW) potentials in different regions of the rotor can be achieved by an asymmetric design of the structure, which provides torque for the rotation of the rotor. We studied the rotation and driving mechanism of the designed system through molecular dynamics (MD) simulation and discussed the influence of the chiral combination of carbon nanotubes, the chirality of graphene substrate, the length of graphene substrate, and the system temperature on rotation. At the same time, this paper also makes a qualitative analysis of the feasibility of the designed system from the perspective of molecular mechanics combined with energy. This research provides a new idea of nanoscale driving rotation, which has guiding significance for the design and application of related nanodevices in the future.

The one-dimensional nanoscaled bar is commonly seen in current nanodevices, and it plays a significant role in nanoelectromechanical system (NEMS) and related nanotechnology. Motivated by this, the paper is concerned with the bending and stability of a nanoscaled bar especially a flexible bar subjected to vertical concentrated, vertical linearly distributed, and horizontal concentrated forces simultaneously. The theoretical model is developed by employing Eringen’s nonlocal differential law. Hence, the nonlocal differential constitutions in terms of stress and bending moment at a nanoscale are applied to the classical equilibrium formulation in order to construct the nonlocal constitutive model and then determine the analytical solutions for bending of such a nanoscale bar. Subsequently, the effect of a nonlocal scale on the midpoint deflections and internal forces is shown numerically, and the internal and external characteristic length scales are also examined. It is revealed that the capacity of resisting compression decreases with increasing the nonlocal effect since the internal characteristic scale cannot be neglected by comparing with the external characteristic scale. There exists a threshold value for bending stiffness. Both the midpoint deflection and bending moment vary monotonously when the material bending stiffness exceeds the threshold value, while the mechanical quantities fluctuate when the bending stiffness is less than its threshold value, namely, for a flexible nanoscaled bar. Accordingly, two different kinds of nonlocal predictions and the related disputes are resolved in the context of Eringen’s nonlocal differential law. The work is expected to be useful for the design, application, and optimization of nanoscaled bars sustaining bending with linear vertical and horizontal forces.

The effect of the addition of cellulose nanocrystals (CNCs) on the properties of cement pastes is studied herein. The compressive strength of CNC/cement paste was investigated under the curing conditions defined in this study. Two-dimensional micrographs and pore size distributions were obtained by scanning electron microscopy, X-ray computed tomography (XCT), and nitrogen adsorption. The addition of CNCs was found to significantly enhance the mechanical properties of cement pastes with a rapid decrease in temperature and humidity. XCT and nitrogen adsorption analyses show that the addition of CNCs leads to a refinement of the pore structure in the cement matrix. Almost no hydration products, including C-S-H, are formed in the cement matrix without CNCs under extreme conditions. This is in contrast with the results for the cement paste with 0.5% CNCs.

Intercalation and exfoliation are key steps in the preparation of graphene by thermal exfoliation, and they determine the quality of the final product. Therefore, it is important to explore the influence of intercalation agents on the intercalation and exfoliation of graphite. In this article, ammonium bicarbonate is intercalated into graphite with different degrees of oxidation to form a graphite intercalation compound (GIC) by means of ultrasound and stirring. Then, they are exfoliated by being heated at high temperatures. After ammonium bicarbonate intercalation and heating treatment, XRD, TG, and BET show that the intercalation and exfoliation effect of graphite oxide (GO) is better than that of graphite (G) and expanded graphite (EG). The intercalation mechanism is that the ammonia molecule in ammonium bicarbonate solution contains a wedge-shaped structure and active point, which provides empty orbits for graphite electrons and forms edge intercalation through physical interaction at the same time.

Carbon dots (CDs) have received significant attention worldwide from the beginning of this century, and recently, it has bloomed in every branch of applied sciences. Because of their outstanding physical and chemical properties together with biocompatibilities, CDs find a wide spectrum of applications in drug delivery, explosive detection, chemical sensing, food safety, bioimaging, energy conversion, photocatalysis, etc. This brief review is focused on the synthesis of CDs and their applications. The photophysical properties of CDs are also discussed herewith.

In this work, the ohmic contact mechanism of Ni electrodes on C-faced 4H-n-SiC was investigated by evaluating the electrical and microstructural properties in the contact interface as a function of annealing temperatures ranging from 950 to 1100°C. We determined that Ni-silicide, especially the NiSi phase, plays a key role in the formation of ohmic contacts rather than an increase in carbon vacancies in the C-faced SiC substrate. A vertically oriented NiSi phase was observed in the thermally annealed sample at the optimized temperature that behaves as a current path. A further increase in annealing temperature leads to the degradation of ohmic behavior due to the formation of horizontal-type NiSi in the Ni-rich Ni-silicide/NiSi/SiC structure.

Application of low-temperature PECVD is a very tempting option for formation of ultrathin silicon layers for nanoelectronic and nanophotonic applications, as followed by annealing of this layer, regardless if executed as individual process performed in controlled ambient or during following high-temperature processes, allows for phase and content changes in the silicon layer. Understanding complex changes that can take place during such process, which depend on its temperature, conditions (e.g., oxygen availability), and timeframe, is a fundamental requirement for conscious application of such technology. It is worth realizing that nanodevices with their unprecedented variety of structures and devices require many different fabrication technologies. Hence, depending on the application in mind, different results of ultrathin silicon layer annealing may appear advantageous. During high-temperature processing (e.g., annealing) of PECVD ultrathin silicon layer, three competing effects have to be taken into account. These are amorphous silicon recrystallization and oxidation of amorphous and crystalline (as-deposited or just recrystallized from as-deposited amorphous phase) silicon (both of which by nature exhibit different kinetics). So far, most of attention has been paid to silicon recrystallization, which was justified by the fact that under experimental conditions studied (silicon multilayers) oxidation was certainly of less importance. In certain applications, the required device structure consists of single (and not multiple) ultrathin silicon layer, and thus, oxidation effects certainly have to be included into considerations. Understanding dynamics and very complex relations between these individual effects is thus mandatory for using consciously this technique and achieving needed properties of the layer. It has to be stated clearly that although the achieved results, presented in this study, refer to the silicon layers fabricated under certain conditions (particular type of PECVD reactor and process parameters), they can, however, be easily extrapolated for similar cases too. The presented below results are, to our knowledge, the first successful attempt to address these issues.

The dental plaque is an oral microbiome hardly associated to be the etiological agent of dental caries and periodontal disease which are still considered serious health public problems. Silver nanoparticles (AgNPs) have demonstrated to have good antimicrobial properties affecting a wide variety of microorganisms, including oral bacteria; however, there is no scientific information that has evaluated the antimicrobial effect of AgNPs against clinical oral biofilms associated with dental caries and periodontal disease. The aim of this study was to determine the antimicrobial and substantivity effects of AgNPs in oral biofilms isolated clinically from patients with dental caries and periodontal disease. Sixty-seven young and young-adult subjects with dental caries and periodontal disease were clinically sampled through the collection of subgingival dental plaque. The inhibitory effect of AgNPs was performed with standard microbiological assays by triplicate using two sizes of particle. Polymerase chain reaction (PCR) assay was used to identify the presence of specific bacterial species. All AgNPs showed an inhibitory effect for all oral biofilms for any age and, generally, any gender (p>0.05); however, the effectiveness of the antimicrobial and substantivity effects was related to particle size, time, and gender (p<0.05). The identified microorganisms wereS. mutans,S. sobrinus,S. sanguinis,S. gordonii,S. oralis,P. gingivalis,T. forsythia, andP. intermedia. The AgNPs could be considered as a potential antimicrobial agent for the control and prevention of dental caries and periodontal disease.

This paper is an expansion of our previous work on the synthesis of graphene oxides and reduced graphene oxides from different kinds of oil palm waste-based feedstocks, namely, OPL (oil palm leaf), PKS (palm kernel shell), and EFB (empty fruit bunch). Here, the electrochemical measurements of the resulting reduced graphene oxides derived via mild-temperature annealing reduction of the graphene oxides were accomplished using cyclic voltammetry and galvanostatic charge/discharge processes. The findings put forward their promising features for supercapacitor applications. For instance, the reduced graphene oxide derived using EFB precursor (rGOEFB) which has a BET surface area of 117 m2 g-1 exhibits a specific capacitance of 688 F g−1 at an applied current density of 0.8 A g-1. This is higher than that observed for reduced graphene oxides derived from oil palm leaf (rGOOPL), palm kernel shell (rGOPKS), and the commercially acquired graphite (rGOCG), which possessed specific capacitance values of 632, 424, and 220 F g−1, respectively. It can be deduced that the specific capacitance of the reduced graphene oxide samples increases in the following order: (rGOCG)

In this study, a novel spray drying-assisted self-assembly (SDAS) technology was proposed to prepare submicron elemental explosives with good morphology, uniform dispersion, and low sensitivity and spherical submicron RDX, HMX, and CL-20 particles without soft agglomeration were fabricated via such a method. Structural characterizations and thermal stability of the composites were systematically studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimeter (DSC). Moreover, safety performance was analyzed by qualitative testing of impact sensitivity and friction sensitivity. The XRD analysis demonstrated that HMX and CL-20 refined by SDAS maintained the crystal structure of β-HMX and ε-CL-20 before and after refinement, whereas the HMX crystal structure after spray recrystallization refinement was transformed from β-HMX to α-HMX. The DSC results indicated that the thermal decomposition peak temperature of the three particles refined by the SDAS technology had a minimum advancement, and the thermal stability of the particles was relatively superior. More importantly, the H50 of the RDX, HMX, and CL-20 refined by this novel method was increased to 48.3 cm, 44.6 cm, and 31.1 cm, and the probability of friction explosion was decreased to 62%, 62%, and 80%, respectively, thus significantly improving the safety performance as compared with the sample refined by spray recrystallization.

The monitoring of chemical and antibiotic residues like amoxicillin, penicillin, tetracycline, and vancomycin in the food originating from the animal and plant sources can prevent the humans from getting exposed to the antibiotic-induced allergic reactions and also decreased immunity towards the microbial population. By taking into consideration the necessity of developing effective and sensitive techniques for milk containing Penicillin G antibiotics in an easy and cost-effective mode, the present work deals with the electrochemical sensor made up of nickel nanoparticles (NiNPs). In order to enhance the chemical stability and biocompatibility, the NiNPs were crosslinked with (3-aminopropyl)triethoxysilane (APTES) and the formed composite was thoroughly characterized using the physical characterization techniques. In addition, the qualitative analysis results confirmed the nanocomposite’s synergetic effect towards the oxidation of Penicillin G. Further, the quantitative analysis towards the use of a nanocomposite electrode due to the changes in pH, scan rate, accumulation time and potential, nanoparticle (NP) amount, etc. was optimized. The limit of detection and limit of quantitation of Penicillin G with this composite were detected to be 0.00031 μM and 0.00100 μM, respectively. Overall, from the results, it can be indicated that the fabricated NiNP sensor can find its applications as a potential electrode material for the qualitative and quantitative analysis of Penicillin G in liquid samples.

Scaffolds have been used as extracellular matrix analogs to promote cell migration, cell attachment, and cell proliferation. The use of aerogels and carbon-based nanomaterials has recently been proposed for tissue engineering due to their properties. The aim of this study is to develop a highly porous collagen-alginate(-graphene oxide) aerogel-based scaffold. The GO synthesis was performed by Hummers method; a collagen-alginate and collagen-alginate-GO hydrogel were synthetized; then, they were treated by a supercritical drying process. The aerogels obtained were evaluated by SEM and FTIR. Osteoblasts were seeded over the scaffolds and evaluated by SEM. According to the characterization, the aerogels showed a highly porous interconnected network covered by a nonporous external wall. According to the FTIR, the chemical functional groups of collagen and GO were maintained after the supercritical process. The SEM images after cell culture showed that a collagen-alginate scaffold promotes cell attachment and proliferation. The alginate-collagen aerogel-based scaffold could be a platform for tissue engineering since it shows adequate properties. Further studies are needed to determine the cell interactions with GO.

The efficiency of nanoparticles covered with type A gel and loaded with KH2PO4, as a source of P, was evaluated on growth, phosphorus concentration and accumulation, and photosynthesis-related parameters in rice plants (Oryza sativa L. ssp. indica) cv. Morelos A-2010, under greenhouse conditions. Plants were treated for 14 days with P concentrations equivalent to 50 and 100% of those established in the Yoshida nutrient solution. Sources of P were KH2PO4, nano-KH2PO4, and nano-KH2PO4 with trypsin; control treatments were distilled water and nanoparticles with type A gel. The solutions were renewed every 7 d. Rice plants exhibited differential P absorption in function of the P source tested. P supplied by KH2PO4 had a higher uptake rate than P supplied by nano-KH2PO4, alone or with trypsin. Nevertheless, nano-KH2PO4 promoted higher physiological efficiency for P in both roots and shoots, which consequently induced higher biomass accumulation in these organs. P concentration in shoots, as well as P accumulation in shoots and roots, were positively correlated with the photosynthetic rate. Also, nano-KH2PO4 increased instant water use efficiency in rice plants.

This study was performed to investigate the biocompatibility (BC), magnetothermal effect, and DNA binding biological characteristics of manganese zinc ferrite nanoparticles (Mn0.6Zn0.4Fe2O4-NPs (MZF-NPs)) coated with pegylated manganese (PEG-MZF-NPs). Their functions as gene transfer carrier for gene therapy and magnetic medium for tumor hyperthermia were also explored. The manganese zinc ferrite nanoparticles were synthesized through high temperature cracking, and their characterizations were discovered. Hemolysis test and MTT assay were performed to evaluate biocompatibility, and their self-heating effects in the alternating magnetic field were investigated. PEG-MZF-NPs with different concentrations were measured by using 7.0 T Micro-MR scanner (MRI) to calculate the T2 value and r2 relaxation rate of each sample. The CD44-shRNA plasmids were constructed, and their ability to bind PEG-MZF-NPs were examined. The DNA release from PEG-MZF-NP/DNA complex and protection of DNA from nuclease digestion were also detected. After CD44-shRNA-EGFP were transfected into the ovarian cancer SK-OV-3 cells by using PEG-MZF-NPs as carriers, the transfection efficiency was detected by a flow cytometer and expression of CD44 mRNA and protein in cells was detected using RT-PCR and Western blot, respectively. We successfully prepared PEG-MZF-NPs with favorable dispersity, magnetic responsiveness, and BC. Typically, the excellent magnetothermal effect can be used for a tumor magnetothermal therapeutic study. In vitro MRI showed the application potential for being magnetic resonance T2 relaxation contrast agents and the possibility to achieve goal of integration of targeting diagnosis and treatment. The CD44-shRNA plasmids have been successfully constructed and concluded that PEG-MZF-NPs may serve as gene transfer carriers for gene therapy.

Zinc oxide nanoparticles (ZnO) have long been utilized as UV-protective sunscreen components due to their high durability and lower skin irritation while maintaining capability for blocking UV rays. However, the dispersal and transparency properties of ZnO need to be enhanced in order to improve the capacity for creating effective sunscreen through control of the physiochemical properties of ZnO. In this study, chitosan or niacinamide, which are suitable functional cosmetic compounds and effective skin lightening agents, are combined with ZnO for the development of better UV-protective products. Each biocompatible coating material is individually attached on its surface after the synthesis of ZnO. The size is 70 nm using the sol-gel method. Their morphology and chemical structure are characterized by FT-IR, XRD, SEM, TEM, TGA, and zeta potential. The results indicate that approximately 50% of chitosan and 5% niacinamide were coated on the ZnO. To confirm the capacity of each surface-coated ZnO with chitosan and niacinamide as a sunscreen, we measured their transmission, reflectance, and sun protection factor (SPF) using a UV spectrophotometer and SPF. As a result, the niacinamide-coated ZnO shows remarkably lower transmission and high reflectance against UV rays than that of bare ZnO and chitosan-coated ZnO. Furthermore, niacinamide-coated ZnO exhibits great lightening effects. Consequently, these results demonstrate that niacinamide coating is highly effective for the production of sunscreen emulsions.

A simple two-step method of growing ZnO nanorod arrays on the surface of BiOI nanosheets was developed under mild environment. The hierarchical structure of ZnO arrays@BiOI nanosheets was characterized by various measurements like X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray detector. The optical absorption of the ZnO arrays@BiOI nanosheets composite was investigated by UV-Vis diffuse reflectance spectra. The photocatalytic degradation of methanol orange under visible light shows that the obtained ZnO arrays@BiOI nanosheets heterostructures exhibit enhanced photocatalytic activity, contrasting to the sum of BiOI nanosheets and ZnO nanorods. The mechanism of the photocatalytic process was discussed. This method of growing ZnO nanorod arrays on other nanosheets also provides a potential method to fabricating other complex structures.

Owing to their capacity for accurate structural control and complex programmability, DNA molecules have been extensively studied in relation to the construction of nanodevices. However, the existing logic gate sections based on DNA self-assembly were independent of each other, which hampered the development of large-scale integrated DNA circuits. Herein, we have explored a logic operation device with excellent scalability based on assembling and selectively releasing AuNPs on DNA origami, and have performed YES gate, OR gate, AND gate, and three-input composite gate. In the experiment, the logic operation result is detected by gel analysis and TEM image. The resolution of the output signals was greatly improved by determining the releasing of AuNPs from two-layer honeycomb origami. Our study provides a promising approach for building more complex large-scale DNA logic circuits.

A novel Mn2+-doped hollow Mn-HMAS aluminosilica (Mn-HMAS) nanoparticle for simultaneous T1-weighted magnetic resonance imaging and drug delivery was reported. The magnetic resonance tests showed that the Mn-HMAS nanoparticles display an excellent T1-weighted magnetic resonance imaging effect with a high T1 relaxivity (r1) of 8.8 mM-1S-1. The MTT assays showed that the Mn-HMAS-DOX nanoparticles possess a better tumour cell inhibition effect than DOX. In addition, the Mn-HMAS nanoparticles also exhibit good stability and noncytotoxicity. These results demonstrated that the Mn-HMAS nanoparticles can be applied for the loading and delivery of various drugs in medicine.

Sintering is an important approach for the alloying of different metals, which is affected by factors such as temperature, grain size, and material properties. And it represents a complex thermodynamic process. This paper had adopted the molecular dynamics methods to investigate the evolution process of nanostructure during the sintering of Cu and Au nanoparticles. The changes in crystalline during the nanosintering process were observed, and the radial distribution function of atoms, the shrinkage ratio, and the sintering neck of the systems were discussed. The initial sintering temperature and melting temperature of the system were obtained; at the same time, the characteristics of the sintering neck with changes in temperature during the nanosintering process were revealed.

Metal-organic frameworks (MOFs) are an intriguing class of porous inorganic-organic hybrid networks synthesized from metal ions with multidentate organic ligands. MOFs have uniform and tunable cavities and tailorable chemistry, making them promising materials for hazardous component removal from the environment. Controllable integration of magnetic nanoparticles (NPs) and MOFs is leading to the creation of many novel multifunctional MOF-based composites, which exhibit advanced performance that is superior to both of the individual units. This review summarizes the recent significant advances in the development of MOF-based magnetic heterostructure materials for the removal of hazardous contaminants from the environment. The successful methods reported till date for the magnetic MOF synthesis are also provided. In the final section, we provide our views on the future development of the magnetic MOF heterostructure materials for the pollution management.

Monolayers of transition metal ReX2 and ReSX (X=S, Se) have been proposed as new electronic materials for nanoscale devices. In this paper, there are three structures: ReS2, Janus ReSSe, and ReSe2. Based on the first-principles theory, we analyzed the structures, electronic properties, and Fermi speed. Remarkably, we studied the stability of structures of ReS2, Janus ReSSe, and ReSe2 monolayers under biaxial tensile and compressive strain by density functional approach. It is worth noting that when the strain changes, not only the band gap changes but also the band gap properties (direct and indirect) also change. The bond gaps decrease with the increase of tensile strain and compressive strain; Moreover, when the strain is greater than 0, the bond angle decreases as the strain increases, and when the strain is less than 0, the bond angle increases as the strain increases.

The kinetically spraying method was used to fabricate an in situ copper- (Cu-) tin (Sn) intermetallic compound (IMC) film with its thickness of approximately 1 μm using a Cu-Sn mixed powder. Microsized Cu (~5 μm) and Sn (~10 μm) powders were mixed at its ratio of 45 : 55 wt.%, respectively, and then deposited onto a silicon substrate, forming an IMC layer. The actual composition of the deposited film was measured to be at a Cu : Sn ratio of 36 : 64 wt.% (in situ kinetically sprayed at 200°C). This kinetically sprayed process uses the energy source of collision and heat energy simultaneously, leading to the formation of an IMC phase. The IMC phase of Cu6Sn5 was formed successfully within 3 minutes of in situ deposition. Moreover, we obtained a Cu6Sn5 phase when the thin film was annealed in a furnace for 1 hour immediately after kinetically spraying at room temperature. However, an IMC phase was not formed in the thin film when kinetically sprayed at room temperature followed by heating on a hot plate for 3 minutes. It seems that the simultaneous supply of collision and heat energy is crucial to result in phase formation. Therefore, we have proven that the kinetically spraying process is capable of fabricating a super-thin layer of IMC film within a short time.

Cellulose nanocrystals (CNCs) have emerged as promising materials for the fabrication of micro/nanoplatforms that can replace tissues more effectively. CNCs offer interesting properties that facilitate the enhancement of polymer properties. Cytotoxicity of rice husk-derived CNCs was evaluated through WST-1 assay in the presence of human mesenchymal stem cells. Electrospinning technique was used to fabricate nanofibers of poly-ε-caprolactone and its composites. Significant improvement in the mechanical property was observed in the composites relative to the pure polymer. This improvement was attributed to the better interfacial interactions between the polymer matrix and CNCs. Notably, better cell viability and differentiation were observed with the composite nanofibers than with the pure polymers. The osteogenic potential of the fabricated nanofibers was assessed by alizarin red S staining and real-time PCR. Enhanced mineralization occurred in the presence of the composite rather than pure polymer nanofibers. Furthermore, the higher levels of osteogenic markers observed with the media containing the composites clearly indicated their osteogenic potential. These results suggested that fabricated composites have the potential to be used as a biomaterial for tissue engineering applications.

Interfacial thermal resistances between heterogeneous materials are still a challengeable subject since the mechanism to explain it quantitatively is not clear in spite of its importance. We propose a Monte Carlo (MC) model to study phonon interfacial elastic and inelastic scattering behaviors for superlattices composed of Si and Ge materials, which substantially reduces the amount of computations. In particular, below Debye temperatures, the molecular dynamics (MD) solution is not precise enough for semiconductors because of quantization errors. In this work, thermal conductivities and thermal rectifications of Si/Ge and Ge/Si superlattices with different periods are investigated separately at temperatures below 200 K.

Changes of the morphology and pore structure of old corrugated container (OCC) fibers during an alkyl ketene dimer (AKD) sizing process were studied. The resulting samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle, and BET surface area analysis. The length of fibers had obvious influence on the AKD sizing effect, and the length of fibers ranged from 100 to 200 meshes showed the best sizing performance. The surface roughness of 0.3% AKD sizing OCC fibers decreased from 27.949 nm to 12.811 nm. Compared with the control sample, the pore volume of fibers sized with 0.1% AKD decreased 4.3% when the average pore diameter was fixed at 2.4~3.0 nm. And when the usage of AKD increased to 0.3% and 0.5%, the pore volume decreased 1.4% and 6.3% accordingly. The decrease in the pore volume of AKD-sized fiber indicated the penetration and deposition of dispersed particles of AKD in the fiber lumens.

The implementation of nanofertilizers in agriculture is the purpose in specific to decrease mineral losses in fertilizing and raises the yield during mineral management as well as supporting agriculture development. Hence, this experiment was conducted in Shebin El-Kom, El-Monifia governorate, Egypt, during two seasons 2017 and 2018 to study the effect of micronutrient oxide nanoparticles of zinc, iron, and manganese, as well as combination between these oxides as a foliar application on the growth, yield, and quality of squash plants. The obtained results showed that the spraying of manganese oxide nanoparticles on the plants led to the best vegetative growth characteristics, also, the characteristics of the fruits, yield, and the content of photosynthetic pigments. On the contrary, the content of organic matter, protein, lipids, and energy gave the highest value in squash fruits that have been sprayed with iron oxide nanoparticles.

The formation of nickel ferrite (NiFe2O4) nanoparticles under hydrothermal conditions has been modeled using a method that combines results of first-principle calculations, elements of aqueous thermochemistry, and experimental free energies of formation. The calculations predict negative formation energies for the (111) surfaces and positive free energies for the formation of bulk nickel ferrite. Based on classical nucleation theory, the combination of the negative surface and positive bulk energies yields thermodynamically stable nickel ferrite nanoparticles with sizes between 30 and 150 nm in the temperature range of 300 to 400 K under alkaline conditions. The surface and bulk energetics as well as the stability of the nickel ferrite nanoparticle as a function of temperature and pH are discussed.

The Y2O2S:Er3+@Y2O2S:Yb3+,Ho3+ core-shell up-conversion (UC) nanoparticles were successfully synthesized by the homogeneous co-precipitation method. The Y2O2S:Er3+@Y2O2S:Yb3+,Ho3+ core-shell nanoparticles exhibit bright green emissions under 980 nm excitation, while the triple-ion doped Y2O2S:Er3+,Yb3+,Ho3+ sample presents mainly red emissions. The intensity ratio of green-to-red emission of the core-shell and conventional triple-ion doped samples are 2.8 and 0.3, respectively. Investigations on the UC mechanisms show that emissions from Er3+ and Ho3+ ions are achieved simultaneously in the core-shell nanoparticles. This is due to the efficient energy transfers of Yb3+→Ho3+ within the shell layer and Yb3+→Er3+ between the shell and the core. While the triple-ion doped Y2O2S: Er3+,Yb3+,Ho3+ sample exhibits mainly the emissions of Er3+ along with weak luminescence of Ho3+ ion. Since the cross relaxation between Er3+ and Ho3+ ions in the Y2O2S:Er3+,Yb3+,Ho3+ nanoparticles can effectively suppress the emissions of Ho3+ ions. Yet, in the core-shell structure, this cross relaxation can be successfully restrained in the core-shell structure where Er3+ is in the core and Ho3+ is in the shell. Therefore, the construction of core-shell structure can improve the luminescence efficiency and provide a route for adjustment of emission color.

A series of nitrogen-doped mesoporous TiO2 nanomaterials and nitrogen-doped mesoporous TiO2/reduced graphene oxide (RGO) composites were successfully prepared by hydrothermal method using triammonium citrate as the nitrogen source. The effects of nitrogen and graphene oxide (GO) dopping on the photocatalytic properties of the TiO2 were investigated to optimize preparation conditions. The results showed that all prepared samples were mainly composed of the anatase phase and possessed a mesoporous structure. The use of the triammonium citrate not only significantly increased the specific surface area of the synthesized samples but also caused the partial reduction of GO to RGO, leading to further increase of the specific surface area and the improvement of quantum efficiency of the photogenerated electrons. All synthesized samples showed superior photocatalytic performance for methyl orange solution. Among them, the NMT/RGO-1.8-10 was found to be the best; the degradation rate of methyl orange solution on the sample reached 100% in 30 minutes under visible light irradiation.

Superparamagnetic magnetite-alginate nanoparticles (M-AlgNPs) were synthesized utilizing a coprecipitation method. Then, the prepared M-AlgNPs were characterized via Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction spectroscopy (XRD) to affirm the formation and the crystallinity of this composite. In addition, the surface morphology of the prepared nanoparticles was inspected by transmission electron microscopy (TEM) which revealed well-dispersed nanoparticles of Fe3O4 into alginate. The adsorption characteristics of the synthesized nanoparticles for removing Ni+2 and Co+2 from wastewater were evaluated via atomic absorption measurements (AAS). The elimination efficiency of the M-AlgNPs was detected at pH=7 in 100 ppm (initial concentration) of Ni+2 and Co+2, separately. The M-AlgNPs provided the maximum equilibrium uptake percentage for Ni+2 and Co+2 of 97.88 and 95.01%, respectively. The adsorption of Ni+2 and Co+2 onto the M-AlgNP surface was found to fit the Langmuir model with R2 values higher than that obtained from the Freundlich model for both metal ions. Moreover, RL “separating factor” for the adsorption process was assessed and found to be less than unity; this expresses the higher ability of the investigated metal ions to be adsorbed onto the M-AlgNP surface. The adsorption method was discovered to be pH-dependent and well-suited to the isothermal equations of Langmuir and Freundlich. For regeneration studies, M-AlgNPs have been investigated and results confirmed that it could be reused with effective sorption capacity over three cycles.

Crinum latifolium (CL) leaf is a source of various biologically active compounds such as alkaloid and phenolic compounds, which exhibit anti-inflammatory, antitumor, and antimicrobial effects. In the purpose of expanding applications for the field of bionanotechnology, we report biosynthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) by using aqueous extract from C. latifolium leaf and explore antibacterial activity and catalytic performance for degradation of pollutants. The formation of CL-AgNPs and CL-AuNPs is confirmed and optimized by UV-visible spectroscopy with surface plasmon resonance (SPR) peaks at around 402 and 539 nm, respectively. The spherical CL-AgNPs have an average diameter of 20.5 nm and the multishaped CL-AuNPs possess an average size of 17.6 nm. The actions of four bacterial strains were strongly inhibited by using the CL-AgNPs. Furthermore, the biosynthesized metallic nanoparticles (MNPs) exhibited the excellent catalytic degradation performance of pollutants.

Introduction. Silver nanoparticles are used in endodontics due to their antimicrobial activity, although it is considered that bacteria are unable to develop resistance to silver nanoparticles. Silver resistance genes have been related to resistance to nanoparticles and antibiotics. The presence of these resistance genes has not been studied in endodontic bacteria. The objective of this study is to report the prevalence of silver resistance genes in endodontic bacteria. Methods. The selected teeth were isolated using a rubber dam and any restoration, post, or caries was eliminated. The operative field was disinfected, and the root-filling material was removed. The samples were obtained using three sterile paper points to absorb the fluid of the root canal. The DNA from the samples and the control organism was extracted, and the detection of the silCBA resistance genes was carried out by PCR. Results. The results of this study show a high prevalence (73.3%) of silCBA silver resistance genes. The Spearman rank correlation coefficient was utilized to identify correlations between the presence of genes and clinical variables. Conclusions. This study reports a high frequency of silver resistance genes related to nanoparticle resistant from bacteria.

The aim of this work is to quantitatively characterize the structural response to a chemical disruption of saturated montmorillonite crystallites by organic molecules (tetracycline (TC)), derived from pharmaceutical waste. The chemical disturbance is performed by varying the surrounding soil solution pH. To show the effect of this chemical perturbation on the interlamellar space (IS) configuration and the hydration properties, an “in situ” XRD analysis, based on the modeling of the 00l reflections, is carried out. The “in situ” XRD analysis is performed by varying the relative humidity conditions (%RH). FTIR SEM and BET- (Brunauer-Emmett-Teller-) BJH (Barrett-Joyner-Halenda) analyses are used as complementary techniques to confirm the structural changes accompanying the intercalation process. Results showed a dependence between solution acid character and the TC adsorption mechanism. From pH values close to 7, the deprotonation of the TC molecule within IS is accelerated by an increasing %RH rate. IR spectroscopy shows that the structure is preserved versus pH value and only a shift of the water deformation bands ascribed to interlamellar water molecule abundance and TC conformation is observed. The surface morphology studied by SEM shows the increase in the surface porosity by increasing the pH value. BET-specific surface area and BJH pore size distribution (PSD) analyses confirm the SEM observations.

Nanomaterials could be modified with various coatings which could modulate their behavior in the environment, bioavailability and toxicity. The purpose of this study was to determine if the selected coatings of silver nanoparticles (nAg) could influence the fate, bioavailability, and toxicity toward suspension feeding freshwater mussels, Elliptio complanata. Mussels were exposed for 96 h to 50 μg/L of nAg with the following surface coatings: citrate, silicate (Si), polyvinylpyrrolidone (PVP), and branched polyethylenimine (bPEI). After the exposure period, mussels were analyzed for total Ag, resistance to air emersion, oxidative stress, genotoxicity, and autophagosome protein uptake (protein ubiquitinylation) in gills and digestive glands. The data revealed that citrate- and PVP-coated nAg were 2 times more abundant in the digestive gland compared to bPEI- and Si-coated nAg with estimated bioaccumulation factors between 5 and 10. The data revealed that tissue Ag levels were closely associated with air survival time, weight loss during air exposure, DNA strand breaks, LPO, and protein-ubiquitin levels in the digestive gland. The data supports the hypothesis that the coatings could influence bioavailability and toxicity in freshwater mussels.

Sponge-like porous Fe2O3 nanomaterials were obtained through the calcination process of the iron-based metal organic framework (MIL-101). As anode materials for lithium-ion batteries, thus, obtained products show a good electrochemical performance with a high specific capacity (1358 mA h g-1 at 100 mA g-1 in the initial cycle) and a relatively stable cycle performance (750 mA h g-1 after 80 charge/discharge cycles). The superior cycling performance may be attributed to their special structure, which facilitates charge transfer and Li+ diffusion.

Carbonaceous nanoscale additives present a pronounced influence on the mechanical properties of both metallic and plastic materials. This paper addresses the fabrication of composite coatings by laser cladding of single-walled carbon nanotubes incorporated by ball milling into a nickel-based powder (NiCrBSiFeC). The coatings were obtained by using the preplaced laser cladding technique on steel substrates. Optical microscopy and SEM microscopy were used to characterise the microstructure refinement of the coatings, and the mechanical behaviour of the coatings has been studied through wear and micro-/nanohardness testing.

Current H2-proton exchange membrane fuel cell systems available for commercial applications employ heavy and high-risk physical hydrogen storage containers. However, these compressed or liquefied H2-containing cylinders are only suitable for ground-based electric vehicles, because although highly purified H2 can be stored in a cylinder, it is not compatible with unmanned aerial vehicles (UAVs), which require a lighter and more stable energy source. Here, we introduce a chemical hydrogen storage composite, composed of ammonia borane (AB) as a hydrogen source and various heterogeneous catalysts, to elevate the thermal dehydrogenation rate. Nanoscale SiO2 catalysts with a cotton structure dramatically increase the hydrogen evolution rate on demand, while simultaneously lowering the startup temperature for AB thermolysis. Results show that the dehydrogenation reaction of AB with a cotton-structured SiO2 nanocatalyst composite occurs below 90°C, the reaction time is less than a minute, and the hydrogen generation yield is over 12 wt%, with an activation energy of 63.9 kJ·mol-1.

A hybrid and hierarchical nanocomposite was successfully prepared by the growth of zeolitic imidazolate framework-8 (ZIF-8) on the template of ionic liquid (IL, [Bmim][BF4]) functionalized reduced graphene oxide (IL-RGO). The structure and morphology of the IL-RGO/ZIF-8 nanocomposite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and Raman spectroscopy. The results showed that RGO sheets were refrained from restacking by IL, and ZIF-8 nanoparticles grew well on the surface of IL-RGO. Owing to the synergistic effect from large surface area and excellent electrocatalytic activity of ZIF-8 and great electrical conductivity of IL-RGO, a highly sensitive sensor for dopamine (DA) can be obtained. IL-RGO/ZIF-8-modified electrode exhibits good electrocatalytic activity and electroconductive properties towards DA which were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Compared with bare or IL-RGO-modified electrodes, the IL-RGO/ZIF-8-modified electrode effectively depressed the oxidation overpotential of DA. The linear response range of DA was from 1.0×10−7 to 1.0×10−4 mol/L with a low detection of limit 3.5×10−8 mol/L. In addition, the sensor was shown to provide satisfactory stability for the determination of DA.

Design of Experiment (DOE) has been used for the optimization of a hydrothermal growth process of one-dimensional fluorine-doped zinc oxide (1D-FZO). Box-Behnken design was used in the DOE which includes three design points on each of the synthesis condition parameters. The condition parameters were the gold sputtering time (10 s, 15 s, and 20 s), hydrothermal reaction time (3 hours, 6.5 hours, and 10 hours), and hydrothermal temperature (50°C, 75°C, and 100°C). This statistical method of DOE was used to study the effects of these hydrothermal conditions on the quality of 1D-FZO produced. Au nanoparticles were used as the catalyst to enable the growth of the 1D-FZO. The XRD and EDX analysis confirmed the formation of polycrystalline FZO with the presence of fluorine, zinc, and oxygen elements. SEM observations indicated that the sputtering time of the Au nanoparticles has significant effect on the morphology and growth process of 1D-FZO. The lowest resistance value of 22.57 Ω was achieved for 1D-FZO grown with the longest Au sputtering time at growth temperature below 100°C.

Low-temperature deposition manufacturing (LTDM) is a technology that combines material extrusion-based 3D printing and thermally induced phase separation (TIPS) into one process. With this feature, both the merits of 3D printing and TIPS can be incorporated including complex geometries with tailorable ordered macroporous features facilitated by 3D printing and microporous/nanoporous features endowed by TIPS. These macroporous/microporous/nanoporous combined structures are important to some important applications such as tissue engineering scaffolds, porous electrodes for electrochemical energy storage, purification, and filtering applications. However, the unique advantages and potential applications of LTDM have not been fully recognized and exploited yet. In this review, we will discuss the origin, principle, advantages, processes, and machine setup of LTDM technology with an emphasis on its unique advantages in fabricating porous materials. Then, current applications of LTDM including porous tissue engineering scaffolds and emerging porous electrodes for electrochemical storage will be described. The versatility of LTDM including its capability of processing a wide range of materials, multimaterial and gradient structures, and core-shell structures will be introduced. Finally, we will conclude with a perspective and outlook on the future development and applications of LTDM technology.

Chitosan-silica (CS-SiO2) hybrid microspheres were prepared through the combined process of sol-gel and emulsification-crosslinking. Their composition, morphology, in vitro bioactivity, and drug release behavior were investigated. The results showed that, when 20 wt% SiO2 was incorporated, the as-prepared CS-SiO2 hybrid microspheres exhibited a regular spherical shape, a high dispersity, and a uniform microstructure. Their average particle diameter was determined to be about 24.0 μm. The in situ deposited inorganic phase of the hybrid microspheres was identified as amorphous SiO2, and its actual content was determined by the TG analysis. As compared with the pure chitosan microspheres, the CS-SiO2 hybrid microspheres displayed a greatly improved in vitro bioactivity. Vancomycin hydrochloride (VH) was selected as a model drug. It was demonstrated that the CS-SiO2 hybrid microspheres presented a good capacity for both loading and sustained release of VH. Moreover, the increase of the SiO2 content efficiently slowed down the drug release rate of the CS-SiO2 hybrid microspheres.

One of the most effective strategies to improve the photoconversion efficiency in the photoelectrochemical cell is by using an assembly of heterostructures. To do so, a simple and inexpensive method, that is successive ionic layer adsorption and reaction (SILAR), is used to deposit the narrow band gap energy semiconductor Bi2S3 on ZnO nanorod arrays (NRAs) at different SILAR cycles. The obtained binary heterostructure thin films were characterized by using X-ray diffraction (XRD), UV-Vis Spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and linear sweep voltammogram (LSV) to prove the crystal structure, optical properties, band gap energy, morphological structure, composition of elements, and electrical properties. The XRD revealed that ZnO NRAs possessed a single wurtzite crystal structure while Bi2S3 possessed an orthorhombic crystal structure. The as-fabricated Bi2S3/ZnO heterostructure exhibited enhanced visible light absorption and charge separation efficiency of photoinduced electron-hole pairs. The band gap energy of binary heterostructure Bi2S3/ZnO NRAs is 3.11, 3.00, 2.33, 1.96, and 1.89 eV at 3, 5, 7, 9, and 11 SILAR cycles, respectively, confirming the substantial improvement of ZnO NRA optical properties. The highest photocurrent density has been achieved by 1.92 mA/cm2 of Bi2S3/ZnO NRAs fabricated at 7 cycles, exhibiting sixfold enhancement compared to that of intrinsic ZnO NRAs (0.336 mA/cm2). This impressive enhancement was ascribed to the significant improvement in morphological structure, crystallinity, and optical properties of heterostructure photoanodes. Significant improvement was achieved in the photoelectrochemical cell (PEC) performance attributed to the fast separation, low recombination rate, and low impedance of the photoinduced electron-hole pairs as shown throughout the electrochemical impedance spectra.

The emergence of drug-resistant pathogens and the abuse of antibiotics have posed dominant threats to society. In this study, we propose an antibacterial use of bovine serum albumin-capped gold nanoclusters (BSA-AuNCs) to address the issue. BSA-AuNCs have a great antibacterial activity against MRSA and VISA which is proved by time-killing curves (TKC). The possible antibacterial mechanisms of BSA-AuNCs against MRSA and VISA are confirmed by fluorescence image observation.

In this work, a kind of nanocomposite paper was obtained by evaporation-induced self-assembly of a mixture of sisal cellulose nanofibers (CNF) and polyethylene glycol (PEG) as the matrix and citric acid (CA) as a cross-linking agent. The CNF/PEG/CA paper exhibited good water swelling resistance which could be controlled by changing the concentration of CA. In addition, this nanocomposite paper exhibited good mechanical properties and water-induced shape memory performance. In particular, when the dosage of CA was 30 wt.%, the tensile strength and the tensile modulus of the CNF/PEG/CA paper after swelling were 25.2 MPa and 813.0 MPa, respectively. Further, this nanocomposite showed great potential for water-induced shape memory materials with fast response speed. The shape recovery rate (Rr) of the CNF/PEG/CA paper reached 90.2% with 30 wt.% CA after being immersed in water for 11 s. It is anticipated that our current work can be used to exploit more efficient methods to overcome the poor water swelling resistance of the cellulose-based shape memory materials.

Developing scaffold materials with excellent biocompatibility, mechanical properties, and controlled drug release properties is vital to tissue engineering. In this study, we fabricated silk fibroin (SF)/poly(lactide-co-glycolide) (PLGA) nanofiber scaffolds containing recombinant human bone morphogenetic protein 2 (rhBMP2) and dexamethasone (DXM) via coaxial electrospinning, which were used in in vitro bone formation with rat bone marrow mesenchymal stem cells (rBMSCs). An in vitro drug release study was adopted to evaluate the sustained release potential of the core-shell structured nanofibers. Furthermore, we detected the potential of the SF/PLGA nanofiber membrane in vitro. In vitro studies showed that rhBMP2 still remained active on the nanofiber membrane. In addition, the dual-drug-loaded nanofiber membrane showed an early burst release of DXM and late sustained release of rhBMP2. rhBMP2 and DXM exhibited strong osteogenic differentiation potential when they acted on rBMSCs. Therefore, the SF/PLGA nanofiber membrane loaded with rhBMP2 and DXM has great potential for the enhancement of bone regeneration.