Rod-shaped Structures Research Articles

PH and near-infrared active; chitosan-coated halloysite nanotubes loaded with curcumin-Au hybrid nanoparticles for cancer drug delivery

In this work, we propose biofriendly in-situ preparation method of Au NPs (hexagonal and rod-shape structures) in the lumen as well as the surface cage of biocompatible halloysite nanotubes (HNTs) using curcumin (CUR) as anticancer drug and subsequently coating with bio-adhesive chitosan (CS) as a polysaccharide. The formation of Au NPs and their interactions with CUR and CS exist in the HNTs has been characterized by FTIR, XRD, XPS, STEM techniques. Interestingly, Au NPs showed longitudinal plasmon resonance bands at 760 and 980 nm that indicate the near-infrared (NIR) responsive property of hybrid nanoparticles. Rod shape and hexagonal structures of Au NPs were produced as confirmed by TEM images. The loading efficiency of CUR was found as much as 12%. Importantly, more CUR release was achieved under acidic conditions (pH 5.5) than basic conditions (pH 7.4). The anticancer potential of HNT hybrid nanoparticles on MCF-7 cancer cells was studied and showed efficient anticancer activity under intracellular tumor cell environment (pH 5.5) than extracellular conditions (pH 7.4). Moreover, the developed HNT hybrid nanoparticles consisting of Au NPs (NIR responsive property) and pH-responsive CUR release could make it suitable for cancer cell-targeted drug delivery platform with NIR-imaging.

1D TiO2 Nanostructures Prepared from Seeds Presenting Tailored TiO2 Crystalline Phases and Their Photocatalytic Activity for Escherichia coli in Water

TiO2 nanotubes were synthesized by alkaline hydrothermal treatment of TiO2 nanoparticles with a controlled proportion of anatase and rutile. Tailoring of TiO2 phases was achieved by adjusting the pH and type of acid used in the hydrolysis of titanium isopropoxide (first step in the sol-gel synthesis). The anatase proportion in the precursor nanoparticles was in the 3–100% range. Tube-like nanostructures were obtained with an anatase percentage of 18 or higher while flake-like shapes were obtained when rutile was dominant in the seed. After annealing at 400°C for 2 h, a fraction of nanotubes was conserved in all the samples but, depending on the anatase/rutile ratio in the starting material, spherical and rod-shaped structures were also observed. The photocatalytic activity of 1D nanostructures was evaluated by measuring the deactivation of E. coli in stirred water in the dark and under UV-A/B irradiation. Results show that in addition to the bactericidal activity of TiO2 under UV-A illumination, under dark conditions, the decrease in bacteria viability is ascribed to mechanical stress due to stirring.

Microstructure of Cadmium Chloride Doped PVA/PVP Blend Films

The structural features of Cadmium Chloride (CdCl2) doped polyvinylalcohol (PVA)- Polyvinylpyrrolidone (PVP) blend films are correlated with their optical and electrical properties. Doping results in formation of self-grown nano-crystalline features; SEM images show the nano-crystals changing shape from spherical to rod-shaped structures, and with further increase in doping level flower shaped crystalline features are observed. There is formation of crystalline micro-globules (10.2 wt%) which modifies to bowl shape, and these crystalline regions disintegrate at 12.1 wt% dopant level. A homogeneous amorphous domain is observed from 15.5 wt% up to 40 wt%. AFM images, XRD patterns and DSC scans are used to complement the discussion based on SEM micrographs in order to explain the electrical and optical properties of this material at different doping levels. The electrical measurements reveal an increase in electrical resistivity at low dopant levels (from 0.5 wt% up to 5.4 wt%), and a decrease in its value on further doping, saturating beyond 15.5 wt% doping level. Optical (UV-Visible) spectra reveal formation of additional energy bands between the HOMO-LUMO levels of PVA-PVP blend films.

Optical properties and charge distribution in rod-shape DNA-silver cluster emitters.

While the atomic structure of DNA_Agn clusters remains unknown many efforts have been made to understand the photophysical properties of this type of systems. It is known that partial oxidation of the silver cluster is necessary for generation of fluorescent emitters. In this sense, the rod-shape model proposed by Gwinn and coworkers (D. Schultz, K. Gardner, S. S. R. Oemrawsingh, N. Markeševic, K. Olsson, M. Debord, D. Bouwmeester, and E. Gwinn, Adv. Mater., 2013, 25, 2797-2803), based on the idea that a neutral rod is generated with Ag+ acting as a "glue" in between the neutral rod and the DNA bases, is a good approximation in order to explain experimental results. With the aim to shed light towards the understanding of these systems, we explore the electronic dynamics and charge distribution in zigzag rod-shape DNA_Agn clusters, using the Ag0/Ag+ stoichiometry found experimentally.

Morphology and molecular phylogeny of Holostichides terrae nov. spec. (Ciliophora: Spirotrichea) with discussion on the possible non-monophyly of Holostichides

In a study to investigate ciliate diversity, we discovered a new soil ciliate. Holostichides terrae nov. spec. was examined and identified based on observations of living cells and stained specimens. In addition, the nuclear SSU rRNA gene along with morphology was analyzed to infer its phylogenetic position. The new species closely resembles H. dumonti, but can be distinguished by the morphology of the pharynx (with rod-shaped structure vs. lacking) and the number of frontoterminal cirri (invariably two vs. usually more than two). Molecular analyses indicate that the genus Holostichides is not monophyletic, and H. terrae is closely related with the genera Birojimia and Hemicycliostyla, both of which have a pharynx with rod-shaped structures, as also seen in H. terrae.

Comparison of morphology and phase composition of hydroxyapatite nanoparticles sonochemically synthesized with dual- or single-frequency ultrasonic reactor

To investigate how a dual- or single-frequency ultrasonic reactor changes the morphology and phase composition of hydroxyapatite nanoparticles (nHAPs), we designed and constructed the preparation of nHAPs using dual- or single-frequency ultrasonic devices, i.e., the single frequency ultrasonic generator with ultrasonic horn (25 kHz), the ultrasonic bath (40 kHz) and the dual-frequency sonochemical systems combined with the ultrasonic horn and the ultrasonic bath simultaneously (25 + 40 kHz). The results showed that the sonicated samples displayed a more uniform shape with less agglomeration than non-sonicated sample. The rod-shaped particles with 1.66 stoichiometry and without a second phase were synthesized successfully in the ultrasonic bath or horn systems. The nHAPs obtained from the dual-frequency ultrasonic systems exhibited a regular rod-shaped structure with better dispersion and more uniform shapes than those of obtained in either ultrasonic bath or horn systems. Additionally, the size of rod-shaped particles obtained in the dual-frequency ultrasound with a mean width of 35 nm and a mean length of 64 nm was smaller than other samples. A possible mechanism is that the dual-frequency ultrasound significantly enhances the cavitation yield over single frequency ultrasound and thus improves the dispersion of particles and reduces the size of the crystals. In addition, irregular holes can be observed in the nanoparticles obtained in the dual-frequency ultrasound. Therefore, the dual-frequency ultrasonic systems are expected to become a convenient, efficient and environmentally friendly synthetic technology to obtain well-defined nHAPs for specific biomedical applications.

Strongest grip on the rod: tarsal morphology and attachment of Japanese pine sawyer beetles

Plant-dwelling beetles overcome challenging attachment hurdles by means of ellaborated, tarsal attachment devices, which are frequently equipped with hairy adhesive pads. While the tarsal functional morphology has been intensively studied in leaf and ladybird beetles during the last decades, longhorn beetles (Cerambycidae) have been widely neglected in experimental studies on insect attachment. However, they are known to strongly hold on to plant substrates, using tarsi that are densely covered with adhesive setae. In the present study, we examined the Japanese pine sawyer beetle, Monochamus alternatus, which lives in an arboreal habitat, as an exemplary case. Traction force of male and female beetles on (1) flat and (2) cylindrical, rod-shaped glass was measured. The substrates are further called (1) glass plate and (2) glass rod.Both male and female M. alternatus bear ribbon-shaped tarsal adhesive setae with broadened, ultrathin terminals. They release a distinct amount of adhesion-mediating fluid after each step. The beetles never walked on the vertically oriented glass plate. However, they performed well on the horizontal plate, as well as on the horizontally and vertically oriented glass rod. Males generated higher forces and safety factors (traction force devided by the body weight) than females, reaching up to 206 mN traction force and a safety factor of 32 on the horizontal glass rod. Thus, they are able to carry their remarkable body weight (ca. 300 mg) throughout a rather long life span.We assume the adaptation of M. alternatus to the attachment on convex and rod-shaped structures to be present in its natural habitat. This longhorn beetle species achieves a proper hold through a combination of interacting parameters: appropriate body alignment and two-sided leg grasping, and generation of normal and friction forces by tarsal pads. This smart attachment system gives rise to the reconsideration of the ecological and evolutionary background, and provides insights for the development of bio-inspired technical grippers.

Synthesis of Rutile TiO2 from Panzhihua Sulfate Titanium Slag by Microwave Heating

This study aimed to assess the utilization of microwave heating for synthesis of rutile TiO2 by employing sulfate titanium slag produced by Panzhihua Iron and Steel Research Institute. To this end, the properties of sulfate titanium slag before and after microwave treatment, i.e., its crystal structure, surface microstructure, and surface chemical functional groups, were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformation infrared (FT-IR) spectroscopy, respectively. Results of XRD analysis showed that the anosovite phase of the sulfate titanium slag transformed to the rutile TiO2 phase under microwave heating at 1100A degrees C for duration of 120 min. Correspondingly, the SEM images revealed that the surface of the sulfate titanium slag grew as a granular substance after microwave roasting. The granular substance was observed to be rutile TiO2 with a rod-shaped structure. FT-IR spectra demonstrated the occurrence of a blue shift at 472.15 cm(-1), indicating phase transformation from anosovite to rutile TiO2 because of the roasting process. From the experimental results, it is concluded that microwave heating can be an effective and efficient approach for the synthesis of synthetic rutile TiO2 from sulfate titanium slag.

Fabrication of InVO4/AgVO3 heterojunctions with enhanced photocatalytic antifouling efficiency under visible-light

With the increasing of bacterial resistance to available antibiotics and water contamination by poisonous organic dyes, it’s necessary to consider how to overcome these concerns. In this paper, novel visible-light-sensitive InVO4/AgVO3 photocatalysts with a p-n junction were synthesized through an ion exchange and in-situ growth process. The obtained photocatalysts were characterized by X-ray powder diffraction (XRD), Transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV-DRS) respectively. It can be observed that the AgVO3 exhibits a rod-shaped structure, while a plentiful of spherical shaped InVO4 particles are formed on the surface. The rod-shaped structure of AgVO3 wasn’t changed by the addition of InVO4, but its photocatalytic properties were tremendously improved. The best photocatalyst was 0.5InVO4/AgVO3, over which the Rhodamine B (RhB) solution was almost decomposed in 200min under visible light irradiation. Moreover, about 99.9999% of P. aeruginosaudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were killed over 0.5InVO4/AgVO3 at 30min. From these results it can be inferred that 0.5InVO4/AgVO3 heterojunctional photocatalyst has an improved efficiency for the separation of the current carriers to enhance the photocatalytic performances. This result provided a valuable design for the novel InVO4/AgVO3 heterojunction photocatalysts with excellent photocatalytic properties used in marine antifouling.

Oxidized pentacene micro-rods obtained by thermal annealing of pentacene thin films in air

Prolonged annealing of pentacene thin films in air leads to the formation of nano- and micro-scale rod-shaped structures at temperatures equal to or higher than 130 °C. Scanning electron microscopy measurements indicated their crystalline structure, while UV–vis absorption spectra revealed presence of different species of oxidized pentacene, including 6,13-pentacenequinone. The mechanism of growth of microcrystals from oxidized pentacene molecules is discussed. Raman and UV–vis absorption spectra dependences on film thickness (in 30–300 nm range) and on thermal annealing conditions (in air and nitrogen at ambient pressure at 100 and 150 °C) were also studied. These spectra are not largely affected by annealing if it is performed in nitrogen at any of studied temperatures and annealing times (few hours to few days). However, if annealing is performed in air, at temperatures 130 °C and higher, changes in spectral features are significant due to film oxidation.

Morphology and Ultrastructure of the Antennal Sensilla of Japanese Sawyer Beetle Monochamus alternatus Hope (Coleoptera: Cerambycidae)

Sensilla are sense organs in insects, generally comprising of a group of cuticle or epi-dermal cells that appear as hairs or rod-shaped structures. Sensilla serve as the functional elements of sensory systems. The morphology and ultrastructure of sensilla on the antennae of mature male and female Japanese sawyer beetles, Monochamus alternatus Hope (Coleoptera: Cerambycidae), were examined by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Five types of sensilla (sensilla basiconica, sensilla trichodea, sensilla digit-like, sensilla rod-like, and sensilla bottle-like) were observed on antennae of males, and four types of sensilla (sensilla basiconica, sensilla trichodea, sensilla bottle-like, and sensilla chaetica) were observed on antennae of females. Sensilla basiconica and sensilla trichodea were found to be abundant on the front elevation of the antennae. TEM micrographs of sensilla basiconica on the antennae of M. alternatus clearly showed that they had no pits in the cuticular region. Micrographs of longitudinal sections of sensilla trichodea showed them to be flat-tipped and smooth-surfaced pegs with pointed tips that are suggestive of a gustatory function. TEM micrographs of sensilla chaetica longitudinal sections showed dendrite branches and no cuticular pore; these sensilla may be involved in the perception of humidity, temperature, heat, and CO2. These results are discussed in relation to the possible roles of the sensilla types in the host-locating behavior of M. alternatus.

The predominant circular form of avocado sunblotch viroid accumulates in planta as a free RNA adopting a rod-shaped secondary structure unprotected by tightly bound host proteins.

Avocado sunblotch viroid (ASBVd), the type member of the family Avsunviroidae, replicates and accumulates in chloroplasts. Whether this minimal non-protein-coding circular RNA of 246-250 nt exists in vivo as a free nucleic acid or closely associated with host proteins remains unknown. To tackle this issue, the secondary structures of the monomeric circular (mc) (+) and (-) strands of ASBVd have been examined in silico by searching those of minimal free energy, and in vitro at single-nucleotide resolution by selective 2'-hydroxyl acylation analysed by primer extension (SHAPE). Both approaches resulted in predominant rod-like secondary structures without tertiary interactions, with the mc (+) RNA being more compact than its (-) counterpart as revealed by non-denaturing polyacryamide gel electrophoresis. Moreover, in vivo SHAPE showed that the mc ASBVd (+) form accumulates in avocado leaves as a free RNA adopting a similar rod-shaped conformation unprotected by tightly bound host proteins. Hence, the mc ASBVd (+) RNA behaves in planta like the previously studied mc (+) RNA of potato spindle tuber viroid, the type member of nuclear viroids (family Pospiviroidae), indicating that two different viroids replicating and accumulating in distinct subcellular compartments, have converged into a common structural solution. Circularity and compact secondary structures confer to these RNAs, and probably to all viroids, the intrinsic stability needed to survive in their natural habitats. However, in vivo SHAPE has not revealed the (possibly transient or loose) interactions of the mc ASBVd (+) RNA with two host proteins observed previously by UV irradiation of infected avocado leaves.

Band gap engineering of niobate composites through incorporation of Ni2+ metal ions and its property evaluation

A simple low cost, two step synthesis route, based on hydrothermal and wet chemical synthesis techniques, has been successfully adopted to prepare pure and Ni2+ doped potassium niobate-sodium niobate (KNi x Nb1-x O3-NaNbO3, x = 0, 0.02, 0.1, 0.25, 0.50) composites (by equal weight percentage). The synthesized materials have been thoroughly analyzed through XRD, FTIR, and HRTEM techniques. Further, morphological analyses through FESEM have revealed existence of mixed morphology, comprising of rod-shaped and irregular spherical structures, in the system. Diffuse Reflectance (DR) UV-Vis spectroscopy has been used to analyze the band gap values of the synthesized materials, and it has been observed that Ni2+ doping has significantly reduced the band gap values of the composites. Methylene Blue (MB) photodegradation analyses under UV irradiation have revealed absence of significant variation in the photodegradation efficiency values of the materials (photocatalysts) on doping. Dielectric studies have revealed low dielectric constant (ɛr) and loss tangent (tan δ) values, indicating an alteration to the perovskite structure of the composite materials, which in effect leads to a possible intensification of the cento-symmetric nature of the individual constituent niobate materials and thus, weakens the dielectric response of the composites in the process.

Biosynthesis of Zinc Oxide Nanoparticles Using Plant Extracts of Aloe vera and Hibiscus sabdariffa: Phytochemical, Antibacterial, Antioxidant and Anti-proliferative Studies

The zinc oxide (ZnO) nanoparticles were successfully synthesized by using aqueous extracts of Aloe vera gel/leaf and Hibiscus sabdariffa leaf, and characterized by FT IR, UV-Vis, XRD, SEM, and EDX techniques. For comparison purposes, ZnO nanoparticles was also synthesized by chemical method. Phytochemical screening of the A. vera gel and leaf and H. sabdariffa leaf extracts showed the presence of alkaloids, carbohydrates, flavonoids, gums and mucilages, saponins, phenolic compounds, tannins, and terpenoids. FT IR spectra showed the presence of functional groups and protein as the stabilizing agent surrounding the ZnO nanoparticles. UV-Vis spectra of ZnO nanoparticles exhibit the characteristic absorption band in the range of 344–360 nm, which can be assigned to the intrinsic bandgap absorption of ZnO due to the electron transitions from the valence band to the conduction band. Powder XRD patterns confirmed the hexagonal wurtzite structure. Further, the SEM analysis also indicates the hexagonal rod shape structure of the ZnO nanoparticles. EDX spectra confirmed the chemical composition of the ZnO nanoparticles synthesized by both biological and chemical methods. In vitro antibacterial activity of ZnO nanoparticles synthesized by both biological and chemical methods were performed on three Gram (−ve) (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) and one Gram (+ve) (Staphylococcus aureus) bacteria, in which the ZnO nanoparticles obtained by biological method showed excellent bactericidal activity over that obtained by chemical method. All the ZnO nanoparticles showed promising antioxidant activity determined by five different methods such as 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS); 2,2′-diphenyl-1-picrylhydrazyl (DPPH); hydrogen peroxide (H2O2); superoxide radical scavenging; and hydroxyl radical scavenging assays. In vitro cytotoxicity of the ZnO nanoparticles were tested against three cancerous cell lines such as human breast adenocarcinoma (MCF-7), cervical (HeLa) and epithelioma (Hep-2), and one normal human dermal fibroblasts (NHDF) cell lines by MTT assay. Apoptosis induction was further confirmed by flow cytometry and cell cycle arrest. The ZnO nanoparticles obtained by biological method display remarkable cytotoxicity against the MCF-7 cell line, and found to be more potent than the widely used drug cisplatin.

Mitotic chromosome assembly despite nucleosome depletion in Xenopus egg extracts.

The nucleosome is the fundamental structural unit of eukaryotic chromatin. During mitosis, duplicated nucleosome fibers are organized into a pair of rod-shaped structures (chromatids) within a mitotic chromosome. However, it remains unclear whether nucleosome assembly is indeed an essential prerequisite for mitotic chromosome assembly. We combined mouse sperm nuclei and Xenopus cell-free egg extracts depleted of the histone chaperone Asf1 and found that chromatid-like structures could be assembled even in the near absence of nucleosomes. The resultant "nucleosome-depleted" chromatids contained discrete central axes positive for condensins, although they were more fragile than normal nucleosome-containing chromatids. Combinatorial depletion experiments underscored the central importance of condensins in mitotic chromosome assembly, which sheds light on their functional cross-talk with nucleosomes in this process.

Oriented clonal cell dynamics enables accurate growth and shaping of vertebrate cartilage.

Cartilaginous structures are at the core of embryo growth and shaping before the bone forms. Here we report a novel principle of vertebrate cartilage growth that is based on introducing transversally-oriented clones into pre-existing cartilage. This mechanism of growth uncouples the lateral expansion of curved cartilaginous sheets from the control of cartilage thickness, a process which might be the evolutionary mechanism underlying adaptations of facial shape. In rod-shaped cartilage structures (Meckel, ribs and skeletal elements in developing limbs), the transverse integration of clonal columns determines the well-defined diameter and resulting rod-like morphology. We were able to alter cartilage shape by experimentally manipulating clonal geometries. Using in silico modeling, we discovered that anisotropic proliferation might explain cartilage bending and groove formation at the macro-scale.

Synthesis and Characterization of PMBN as A Biocompatible Nanopolymer for Bio-Applications.

Objective Poly [2-methacryloyloxyethyl phosphoryl choline (MPC)-co-n-buthyl methacrylate (BMA)-co-p-nitrophenyl-oxycrabonyl poly ethylene glycol-methacrylate (ME- ONP)] (PMBN), a biocompatible terpolymer, is a unique polymer with applications that range from drug delivery systems (DDS) to scaffolds and biomedical devices. In this research, we have prepared a monomer of p-nitrophenyl-oxycarbonyl poly (ethylene glycol) methacrylate (MEONP) to synthesize this polymer. Next, we designed and prepared a smart, water soluble, amphiphilic PMBN polymer composed of MPC, BMA, and MEONP. Materials and Methods In this experimental study, we dissolved MPC (4 mmol, 40% mole fraction), BMA (5 mmol, 50% mole fraction), and MEONP (1 mmol, 10% mole fraction) in 20 ml of dry ethanol in two necked flasks equipped with inlet-outlet gas. The structural characteristics of the synthesized monomer and polymer were determined by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (H-NMR), dynamic light scattering (DLS), gel permeation chromatography (GPC), scanning electron microscope (SEM), and transmission electron microscope (TEM) analyses for the first time. We treated the polymer with two different cell lines to determine its biocompatibility. Results FT-IR and H-NMR analyses confirmed the synthesis of the polymer. The size of polymer was approximately 40 nm with a molecular weight (MW) of 52 kDa, which would be excellent for a nano carrier. Microscopic analyses showed that the polymer was rodshaped. This polymer had no toxicity for individual cells. ConclusionWe report here, for the first time, the full properties of the PMBN polymer. The approximately 40 nm size with an acceptable zeta potential range of -8.47, PDI of 0.1, and rod-shaped structure indicated adequate parameters of a nanopolymer for nano bioapplications. We used this polymer to design a new smart nano carrier to treat leukemia stem cells based on a target DDS as a type of bio-application.

Some features of calculation of the reinforced concrete bent elements and economic assessment of design

At the design stage of the reinforced concrete bent elements, and also at their strengthening by method of accumulation of section, it is necessary to aspire to that the settlement strain-stress distribution of an element corresponded to actual. Importance of this circumstance is that their discrepancy can lead to increase in both economic, and not economic risks at exploitation of construction. In this article some features of calculation which are directly influencing profitability during creation new or strengthening of the rod-shaped bending structure are considered.

Сложный изгиб и начальное разрушение гибридных деревянных брусьев

Разработана математическая модель деформирования гибридных деревянных брусьев. Под гибридными понимаются брусья, образованные путем жесткого соединения (склеивания) по определенным контактным поверхностям набора слоев различных форм поперечных сечений и разных пород древесины. В общем случае брусья находятся в условиях сложного изгиба с растяжением-сжатием. Учитывается физическая нелинейность древесины, а также разное сопротивление растяжению и сжатию. В общем случае задача сводится либо к решению системы трех нелинейных алгебраических уравнений третьей степени относительно обобщенных деформаций поперечного сечения либо к системе трех нелинейных обыкновенных дифференциальных уравнений относительно компонент вектора перемещения точек оси стержня. Для решения полученных алгебраических уравнений используется метод Ньютона, решение дифференциальных уравнений производится с помощью метода галеркинского типа. Предложена аналитическая аппроксимация опытных диаграмм растяжения-сжатия древесины вдоль волокон в виде многочленов второй и третьей степени. Коэффициенты аппроксимирующих функций определяются двумя способами: с помощью метода наименьших квадратов, используя опытные диаграммы деформирования; с помощью наложения определенных требований на диаграммы, используя основные механические характеристики древесины (максимальные напряжения и деформации, модули упругости). Даны численные значения коэффициентов аппроксимации для 15-ти различных пород древесины. Приведенные примеры расчетов гибридных деревянных брусьев показали возможность возникновения скрытых механизмов разрушения (когда предельные деформации достигаются во внутренних слоях стержня). Установлено существенное влияние перестановки материалов слоев на напряженно-деформированное состояние конструкции. Разработанный в статье метод расчета гибридных стержневых деревянных конструкций открывает большие возможности для решения задач оптимизации при проектировании и позволяет рациональным способом использовать различные породы древесины.

Size control of 1D Sb2Se3 nanorods prepared by a facile mixed solvothermal method with tartaric acid assistance

Sb2Se3 can readily form long, 1D rod-shaped structures due to the intrinsic properties of orthorhombic Sb2Se3 crystals. Herein, short, 1D rod-shaped Sb2Se3 was synthesized by a facile mixed solvothermal method with tartaric acid (TA) assistance, and the synthetic mechanism is illustrated. Different sizes of 1D Sb2Se3 nanorods could be achieved by controlling the reaction temperature and using THF as a solvent to increase the reaction pressure. The formation of long, 1D rod-shaped Sb2Se3 when sodium tartrate was added instead of tartaric acid was explained by the coordination and dissociation equilibrium of antimony potassium tartrate. The effect of different amounts of TA on Sb2Se3 morphology was interpreted based on the precipitation–dissolution equilibrium of Sb2Se3. This study provides an effective method to control the sizes of Sb2Se3 nanorods.