Unstable Reaction Research Articles

Microfluidics-Assisted Synthesis of Hierarchical Cu2 O Nanocrystal as C2 -Selective CO2 Reduction Electrocatalyst.

Copper-based catalysts have attracted enormous attention due to their high selectivity for C2+ products during the electrochemical reduction of CO2 (CO2 RR). In particular, grain boundaries on the catalysts contribute to the generation of various Cu coordination environments, which have been found essential for C-C coupling. However, smooth-surfaced Cu2 O nanocrystals generally lack the ability for the surface reorganization to form multiple grain boundaries and desired Cu undercoordination sites. Flow chemistry armed with the unparalleled ability to mix reaction mixture can achieve a very high concentration of unstable reaction intermediates, which in turn are used up rapidly to lead to kinetics-driven nanocrystal growth. Herein, the synthesis of a unique hierarchical structure of Cu2 O with numerous steps (h-Cu2 O ONS) via flow chemistry-assisted modulation of nanocrystal growth kinetics is reported. The surface of h-Cu2 O ONS underwent rapid surface reconstruction under CO2 RR conditions to exhibit multiple heterointerfaces between Cu2 O and Cu phases, setting the preferable condition to facilitate C-C bond formation. Notably, the h-Cu2 O ONS obtained the increased C2 H4 Faradaic efficiency from 31.9% to 43.5% during electrocatalysis concurrent with the morphological reorganization, showing the role of the stepped surface. Also, the h-Cu2 O ONS demonstrated a 3.8-fold higher ethylene production rate as compared to the Cu2 O nanocube.

Sodium Metal Anodes with Self‐Correction Function Based on Fluorine‐Superdoped CNTs/Cellulose Nanofibrils Composite Paper

AbstractDespite much efforts to stabilize sodium metal anodes for promoting their commercial applications, achieving a safe cycling process without intrinsic dendrite growth remains difficult owing to the unstable reaction interface and irregular sodium metal propagation. Herein, fluorine‐superdoped carbon nanotubes with a fluorine content of 14.38 at% are achieved using a new oxidation‐assisted plasma strategy, and then alternately assembled with cellulose nanofibrils to form periodical conductive/dielectric composite paper with outstanding mechanical properties. The superdoping of fluorine facilitates the construction of a NaF‐dominated solid electrolyte interphase layer, while the periodical conductive/dielectric network re‐homogenizes electric field distribution around irregular sodium protrusions, realizing a “bottom‐up” sodium orientation deposition and the “self‐correction” functionality during sodium plating/stripping process. Density functional theory calculations reveal that the specific oxygen species (CO/CO) and fluorine species (semi‐ionic CF/covalent CF2) on the surface of carbon matrix, could remarkably trap active fluorine fragments and generate NaF with sodium metal, respectively, which promotes the superdoping of fluorine and forms dendrite‐free sodium anodes. This delicate structure renders the sodium anodes a low nucleation overpotential of ≈7 mV, high Coulombic efficiency of 99.5% over 300 cycles at 3 mA cm−2, stable operation for up to 2100 h under ≈16 mV, and excellent full battery performance.

The multicomponent synergistic effect of a hierarchical Li0.485La0.505TiO3 solid-state electrolyte for dendrite-free lithium-metal batteries.

Development of a composite electrolyte with high ionic conductivity, excellent electrochemical stability and preeminent mechanical strength is beneficial for suppressing Li-dendrite penetration and unstable interfacial reactions in solid-state Li-metal batteries. Herein, a novel composite electrolyte material comprising perovskite Li0.485La0.505TiO3 (LLTO), poly(ethylene oxide) (PEO), and a barium titanate (BTO)-polyimide (PI) composite matrix has been successfully fabricated. Benefiting from the well-defined ion channels, the resulting BTO-PI@LLTO-PEO-FEC-LiTFSI (BP@LPFL) exhibits excellent cycling stability, low interfacial resistance, enhanced mechanical strength, and high ionic conductivity. Particularly, BP@LPFL possesses an excellent ionic conductivity of 3.0 × 10-4 S cm-1 at room temperature and achieves a wide electrochemical window of 5.2 V (vs. Li+/Li). For Li-LiFePO4 batteries, such an ingenious structure yields a discharge capacity of 124 mA h g-1 at 0.1 C after 200 cycles at room temperature and delivers a discharge capacity of 165 mA h g-1 at 0.1 C after 110 cycles at 60 °C. Additionally, the symmetric Li cell remains stable after 700 h at a current density of 0.5 mA cm-2. Furthermore, ex situ X-ray photoelectron spectroscopy and ex situ scanning electron microscopy were used to verify the interface evolution. Besides, a flexible full battery is fabricated, which exhibits impressive performance. These properties presented here provide support for BP@LPFL as a feasible candidate electrolyte for solid-state lithium batteries.

Anhydrous Hydrogen Iodide-Mediated Reductive Indolization of In Situ-Generated Cyclopropyl Hydrazones.

Fischer-type indolization of N-aryl-C-cyclopropyl hydrazones generated in situ followed by chemoselective reduction using tert-butyl iodide as an anhydrous HI generator was developed. This protocol provides indoles bearing carboxylic acid derivative units. A series of control experiments indicated the HI-mediated formation and reduction of spirocyclopropyl indolenines. Anhydrous HI functions as a Brønsted acid as well as a reducing agent, facilitating the successful conversion of unstable reaction intermediates and iodinated mixtures in equilibrium.

Understanding How Coacervates Drive Reversible Small Molecule Reactions to Promote Molecular Complexity

Liquid-liquid phase-separated coacervate droplets give rise to membraneless compartments that play an important role in the spatial organization and reactivity in cells. Due to their molecularly crowded nature and ability to sequester biomolecules, coacervate droplets create distinct environments for enzymatic reaction kinetics and reaction mechanisms that markedly differ from bulk solution. In this work, we use a combination of experiments and quantitative modeling to understand how coacervate droplets promote reversible small molecule reaction chemistry. In particular, we study a model condensation reaction generating an unstable fluorescent imine in polyacrylic acid-polyethylene glycol coacervate droplets over a range of conditions. At equilibrium, the concentration of the imine product in coacervate droplets is approximately 140-fold larger than that in bulk solution, which arises due to preferential partitioning of reactants and products into coacervate droplets and a reaction equilibrium constant that is roughly threefold larger in coacervate droplets than in solution. A reaction-diffusion model is developed to quantitatively describe how competing reaction and partitioning equilibria govern the spatial distribution of the imine product inside coacervate droplets. Overall, our results show that compartmentalization stabilizes kinetically labile reaction products, which enables larger reactant concentrations in coacervate droplets compared to bulk solution. Broadly, these results provide an improved understanding of how biomolecular condensates promote multistep reaction pathways involving unstable reaction intermediates and suggest how coacervates provide a potential abiotic mechanism to promote molecular complexity.

Seismic Retrofitting of a Structure with Soft Storey and Floating Column.

Tremors are called one in everything about preeminent erratic and annihilating of every cataclysmic event, be that as it may, the flighty idea of the incidence of those seismic tremors makes it inconvenient to hinder loss of living souls and annihilation of properties, if the constructions don’t seem to be designed to oppose such seismic tremor powers. During this paper, a shot has been made to review set up irregularities specifically torsional irregularity and re-entrant corners within the frame structure. These inconsistencies square measure made according to IS 1893:2016 (part1) code. Irregular model and regular model were considered which were analyzed exploitation ETABS 2018 to see the unstable reaction of the structure. The models were analyzed exploitation static and dynamic ways, parameters thought-about being displacement, storey drift, torsional irregularity.

Seismic Performance of L-Shaped Building Through Plan Irregularities

Tremors are called one in everything about preeminent erratic and annihilating of every cataclysmic event, be that as it may, the flighty idea of the incidence of those seismic tremors makes it inconvenient to hinder loss of living souls and annihilation of properties, if the constructions don’t seem to be designed to oppose such seismic tremor powers. During this paper, a shot has been made to review set up irregularities specifically torsional irregularity and re-entrant corners within the frame structure. These inconsistencies square measure made according to IS 1893:2016 (part1) code. Irregular model and regular model were considered which were analyzed exploitation ETABS 2018 to see the unstable reaction of the structure. The models were analyzed exploitation static and dynamic ways, parameters thought-about being displacement, story drift, torsional irregularity.

Interfacial defect engineering via combusted graphene in V2O5 nanochips to develop high‐rate and stable zinc-ion batteries

With the increasing demand of energy sources, various electrical devices have attracted considerable attention. Rechargeable aqueous zinc-ion batteries (ZIBs) represent an attractive choice in the battery industry owing to their unique properties of a high specific capacity, reliable safety, and eco-friendliness. However, the practical application of ZIBs is hindered owing to the unstable energy storing reactions of the vanadium-based cathode, which occur because of the limited electrochemical capacity and kinetics. In this study, we formulated an original strategy based on defect engineering to form interface-defective V2O5 nanochips by using combusted graphene in the electrospun polyacrylonitrile fiber template method. This framework exhibits a high specific capacity, rate capability, and long-tern cycling stability, with a high energy density of 437 W h kg−1 at a power density of 450 W kg−1. These improvements can be attributed to the acceleration of the diffusion kinetics of zinc ions and electrical conductivity of the electrode via the interfacial Vo and facilitation of the active and stable receptivity of electrochemical reactions between electrons and zinc ions through the provision of interfacial open channels. The proposed approach can promote the development of a promising cathode electrode for high‐rate and stable ZIBs as next-generation energy technologies.

Trajectory Tracking Control for Reaction–Diffusion System with Time Delay Using P-Type Iterative Learning Method

This paper has dealt with a tracking control problem for a class of unstable reaction–diffusion system with time delay. Iterative learning algorithms are introduced to make the infinite-dimensional repetitive motion system track the desired trajectory. A new Lyapunov–Krasovskii functional is constructed to deal with the time-delay system. Picewise distribution functions are applied in this paper to perform piecewise control operations. By using Poincaré–Wirtinger inequality, Cauchy–Schwartz inequality for integrals and Young’s inequality, the convergence of the system with time delay using iterative learning schemes is proved. Numerical simulation results have verified the effectiveness of the proposed method.

Stabilizing Intermediate Phases via Efficient Entrapment Effects of Layered VS4/SnS@C Heterostructure for Ultralong Lifespan Potassium‐Ion Batteries

AbstractPotassium‐ion batteries (PIBs) have appealed increasing attention due to the inexpensive K‐element resources and satisfactory electrochemical properties. Presently, there are still challenges for developing desirable anode materials. Two‐dimensional metal sulfides exhibit high specific capacity as host for PIBs, yet the dissolution and agglomeration of unstable reaction intermediate KxSy (K2S, K2S5) inescapability induces large loss of active ingredients and poor reactions reversibility, leading to inferior lifespan. Herein, polar polysulfide VS4 is introduced into SnS nanosheets with constructing layered VS4/SnS heterostructure anchored in graphene scaffold (VS4/SnS@C). In this framework, VS4 with unsaturated bridging (S2)2– can act as the anchoring sites to stabilize intermediates KxSy with efficient entrapment effects. Moreover, the heterostructure can maintain layered SnS and regulate the distribution of KxSy with high conversion reversibility. The reaction reversibility and intermediate absorptivity are enhanced, as confirmed by in situ X‐ray diffraction analysis and theoretical calculations. Consequently, the VS4/SnS@C electrode exhibits ultra‐long lifespans, which achieves a capacity of 168.4 mAh g–1 at 1 A g–1 after 6000 cycles. This strategy of heterostructure design facilitates the understanding of K‐storage mechanisms and significantly enhances the reaction reversibility, providing a thought to address the challenges in metal sulfide anodes toward the development of high‐performance PIBs.

Development of a novel cathodic deposition method for thin-film metal azolate frameworks toward Cd2+ adsorption

Metal-Organic Frameworks (MOFs) have attracted much attention due to its large specific surface, flexible porosity and unsaturated coordination bonds. Cathodic deposition is a unique in-situ potential-driven synthesis method for the deposition of thin film MOFs; however, the gradually consumption of reactants during cathodic deposition might lead to unstable and uncontrollable reaction during thin-film MOF deposition. Herein, oxygen is selected as the initial reactant for the formation of OH−, which can result in gradually and successive formation of thin-film MAF-66 (Metal azolate framework-66), and the particle size and film thickness of the MAF-66 film can be easily tuned by the deposition time. Furthermore, the cathodic deposited thin-film MAF-66 show good adsorption property for heavy metal ions, with Cd2+ as a representative species. The adsorption capacity can reach 32.3 ​mg/g (removal ratio: 69%) and the deposited MAF-66 film can achieve a satisfactory recovery degree with structural and morphological stability. In this way, a novel, environmental-friendly, and controllable cathode deposition method is developed for preparation of thin-film MAF-66, which also show great promise as a candidate for heavy metal ions adsorbent.

TINCIÓN MODIFICADA PARA OBSERVACIÓN DE FLAGELOS EN Bacillus amyloliquefaciens POR MICROSCOPÍA ÓPTICA

<p><strong>Background:</strong> <em>Bacillus amyloliquefaciens</em> is a plant growth-promoting rhizobacterium and produces several secondary metabolites with antimicrobial activity. One of its most important morphological characteristics is the presence of flagella. Currently the existing staining techniques for bacterial flagellar visualization have limitations; as increased time requirement and unstable reactions of the reagents. <strong>Objective: </strong>Therefore, the objective of this study was to describe a modification in the flagellar staining methodology, to visualize flagella in <em>B. amyloliquefaciens</em> bacteria by light microscopy. <strong>Methodology: </strong>Mordant was used (80 mL of 25% tannic acid solution and 15 mL of 2.5% chromium trioxide, it was mixed and left to rest for 5 days at 4 °C) and crystal violet, in bacterial colonies of 16, 18, 20, 22 and 24 h of growth. <strong>Results: </strong>After a growth period of 20-24 h, in bacterial cells of <em>B. amyloliquefaciens</em>, the presence of peritric flagella was observed (flagella distributed on the surface of the bacteria), which was possible through the modified flagellar staining technique developed. <strong>Implications: </strong>The correct, fast and practical visualization of bacterial flagella is important for morphological identification. <strong>Conclusion: </strong>In this research it was possible to demonstrate the visualization of bacterial flagella, with a modified technique and less manipulation of the bacteria.</p>

Bifurcations and Synchronization in Networks of Unstable Reaction–Diffusion Systems

This article is devoted to the analysis of the dynamics of a complex network of unstable reaction–diffusion systems. We demonstrate the existence of a non-empty parameter regime for which synchronization occurs in non-trivial attractors. We establish a lower bound of the dimension of the global attractor in an innovative manner, by proving a novel theorem of continuity of the unstable manifold, for which we invoke a principle of spectrum perturbation of non-bounded operators. Finally, we exhibit a co-dimension 2 bifurcation of the unstable manifold which shows that synchronization is compatible with instabilities.

Regulation of superoxide dismutase activity in soybean plants by inoculating seeds with rhizobia containing nanoparticles of metal carboxylates under conditions of different water supply

Soybean is one of the most profitable advanced crops in agricultural production in Ukraine and the world as a whole. Therefore, studies of means of regulation and increase in the adaptive capacity of soybeans in symbiosis with nodule bacteria under the action of unfavourable environmental factors are relevant and should be aimed at the use of complex bacterial compositions involving modern nanotechnological approaches. Nanocarboxylates of ferrum, molybdenum and germanium metals were used as components of rhizobia inoculation suspension for soybean seed treatment to study the effectiveness of their complex effect on the regulation of the activity of the key antioxidant enzyme superoxide dismutase in plants under drought. Various symbiotic systems were used, which included soybean plants and inoculation suspensions based on the active, virulent Tn5-mutant Bradyrhizobium japonicum B1-20 by adding nanoparticles of ferrum, germanium and molybdenum carboxylates to the culture medium in a ratio of 1: 1000. Citric acid was the chelator. A model drought lasting 14 days was created during the period of active fixation of atmospheric molecular nitrogen by root nodules of soybeans in the budding and flowering stages, by means of controlled watering of plants to 30% of the total moisture content. In the stage of bean formation, watering of plants was resumed to the optimal level – 60% of the total moisture content. The control was soybean plants, the seeds of which were inoculated with a suspension of rhizobia without the addition of chelated metals. The following research methods were used in the work – microbiological, physiological and biochemical. According to the results, it was found that when nanoparticles of carboxylates of ferrum, molybdenum and germanium were added to the inoculation suspension of rhizobia, there was an increase in superoxide dismutase activity in root nodules and a decrease in soybean leaves under optimal water supply conditions of plants. This indicates the initial changes in the activity of the antioxidant enzyme in these symbiotic systems, induced by the influence of chelated metals in combination with the rhizobia of the active Tn5-mutant B. japonicum B1-20. Prolonged drought induced an increase in the overall level of superoxide dismutase activity in soybean nodules and leaves, compared to plants grown under optimal watering conditions. The symbiotic system formed by soybeans and B. japonicum with molybdenum carboxylate nanoparticles was the most sensitive to long-term drought exposure, compared to two other soybean-rhizobial symbioses using ferrum and germanium nanocarboxylates. This was manifested in the unstable reaction of the enzyme to the action of drought – suppression or intensification of the level of its activity in the root nodules and leaves of soybeans inoculated with rhizobia containing molybdenum carboxylate nanoparticles. In symbiotic systems with the participation of germanium and ferrum nanocarboxylates, slight changes were revealed in superoxide dismutase activity in root nodules and leaves of plants during drought and restoration of enzyme activity to the level of plants with optimal watering after water stress. It is concluded that the addition to the culture medium of rhizobia Tn5-mutant B1-20 of nanocarboxylates of germanium or ferrum is an effective means of regulating the activity of the antioxidant enzyme superoxide dismutase in soybean root nodules and leaves, which can contribute to an increase in the protective properties and adaptation of plants to the action of dehydration.

Mg‐Pillared LiCoO2: Towards Stable Cycling at 4.6 V

AbstractLiCoO2 is used as a cathode material for lithium‐ion batteries, however, cationic/anodic‐redox‐induced unstable phase transitions, oxygen escape, and side reactions with electrolytes always occur when charging LiCoO2 to voltages higher than 4.35 V, resulting in severe capacity fade. Reported here is Mg‐pillared LiCoO2. Dopant Mg ions, serving as pillars in the Li‐slab of LiCoO2, prevent slab sliding in a delithiated state, thereby suppressing unfavorable phase transitions. Moreover, the resulting Li‐Mg mixing structure at the surface of Mg‐pillared LiCoO2 is beneficial for eliminating the cathode‐electrolyte interphase overgrowth and phase transformation in the close‐to‐surface region. Mg‐pillared LiCoO2 exhibits a high capacity of 204 mAh g−1 at 0.2 C and an enhanced capacity retention of 84 % at 1.0 C over 100 cycles within the voltage window of 3.0–4.6 V. In contrast, pristine LiCoO2 has a capacity retention of 14 % within the same voltage window.

Mg-Pillared LiCoO2 : Towards Stable Cycling at 4.6 V.

LiCoO2 is used as a cathode material for lithium-ion batteries, however, cationic/anodic-redox-induced unstable phase transitions, oxygen escape, and side reactions with electrolytes always occur when charging LiCoO2 to voltages higher than 4.35 V, resulting in severe capacity fade. Reported here is Mg-pillared LiCoO2 . Dopant Mg ions, serving as pillars in the Li-slab of LiCoO2 , prevent slab sliding in a delithiated state, thereby suppressing unfavorable phase transitions. Moreover, the resulting Li-Mg mixing structure at the surface of Mg-pillared LiCoO2 is beneficial for eliminating the cathode-electrolyte interphase overgrowth and phase transformation in the close-to-surface region. Mg-pillared LiCoO2 exhibits a high capacity of 204 mAh g-1 at 0.2 C and an enhanced capacity retention of 84 % at 1.0 C over 100 cycles within the voltage window of 3.0-4.6 V. In contrast, pristine LiCoO2 has a capacity retention of 14 % within the same voltage window.

Near-Atomic-Thick Bismuthene Oxide Microsheets for Flexible Aqueous Anodes: Boosted Performance upon 3D → 2D Transition

Aqueous batteries provide safety, but they usually suffer from low energy and short lifetimes, limiting their use for large-scale energy storage. Two-dimensional materials with infinite lateral dimensions have inherent properties such as high surface area and remarkable power density and cycling stability that are shown to be critical for the next generation of energy storage systems. Here, ultrathin bismuthene oxide with a large aspect ratio is studied as an anode material for rechargeable aqueous metal-ion batteries. The metal oxides are prepared via a novel electrochemical system allowing for a smooth, high-quality transition of bismuthene to bismuthene oxide in a short time. This anodic system is shown to overcome major limiting factors of such batteries, including low capacity and irreversible and unstable redox reactions in aqueous electrolytes. The essential energy storage properties of two-dimensional (2D) microsheets, without the addition of conductive additives and binders, are compared with those of the corresponding three-dimensional (3D) structures. Notably, the battery performance of 2D microsheets is significantly better than that of nanoparticles from all examined aspects, including power density and potential and cycling stability, while exhibiting a capacity density close to their theoretical value. Moreover, 2D microsheets have shown impressive mechanical flexibility related to the ultrathin thickness of individual microsheets and strong interaction between them after film deposition. Combining the excellent energy storage properties of bismuthene oxide, the simple electrode preparation procedure, the inherent flexing characteristic, and the nontoxicity of both the battery material and the electrolyte makes this 2D material an exceptional candidate for large-scale wearable green electronics.

Effect of NaOH and precursor concentration on size and magnetic properties of FeCo nanoparticles synthesized using the polyol method

In this study, the effects of NaOH and precursor concentration on the particle size and magnetic properties of FeCo nanoparticles are investigated. Results suggest that an optimized ratio of NaOH molar concentration [OH] to precursor molar concentration [M] is required to obtain a small particle size, high saturation magnetization, and low coercivity. When the [OH]/[M] ratio was greater than 40, the FeCo nanoparticles aggregated, whereas when the [OH]/[M] ratio was less than 20, FeCo + CoFe2O4 nanoparticles were obtained due to unstable reduction reactions. When [OH]/[M] was 40, the 387 nm FeCo nanoparticles showed the highest saturation magnetization and lowest coercivity, which are the best conditions for achieving high permeability. In contrast, the complex permeability of the 173 nm FeCo nanoparticles was higher than that of the 387 nm FeCo nanoparticles owing to the decrease in the demagnetization effect in the high frequency band. This confirmed that the particle size had a greater effect on the complex permeability than that on the saturation magnetization and coercivity in GHz ranges.

Two-step reaction mechanism reveals new antioxidant capability of cysteine disulfides against hydroxyl radical attack

Cysteine disulfides, which constitute an important component in biological redox buffer systems, are highly reactive toward the hydroxyl radical (•OH). The mechanistic details of this reaction, however, remain unclear, largely due to the difficulty in characterizing unstable reaction products. Herein, we have developed a combined approach involving mass spectrometry (MS) and theoretical calculations to investigate reactions of •OH with cysteine disulfides (Cys-S-S-R) in the gas phase. Four types of first-generation products were identified: protonated ions of the cysteine thiyl radical (+Cys-S•), cysteine (+Cys-SH), cysteine sulfinyl radical (+Cys-SO•), and cysteine sulfenic acid (+Cys-SOH). The relative reaction rates and product branching ratios responded sensitively to the electronic property of the R group, providing key evidence to deriving a two-step reaction mechanism. The first step involved •OH conducting a back-side attack on one of the sulfur atoms, forming sulfenic acid (-SOH) and thiyl radical (-S•) product pairs. A subsequent H transfer step within the product complex was favored for protonated systems, generating sulfinyl radical (-SO•) and thiol (-SH) products. Because sulfenic acid is a potent scavenger of peroxyl radicals, our results implied that cysteine disulfide can form two lines of defense against reactive oxygen species, one using the cysteine disulfide itself and the other using the sulfenic acid product of the conversion of cysteine disulfide. This aspect suggested that, in a nonpolar environment, cysteine disulfides might play a more active role in the antioxidant network than previously appreciated.

Mandibular allotransplant procedures in dogs with the immunosuppressive agent FK506

ObjectiveTreatment of mandibular lesions sometimes leads to the formation of large defects in the bone. Mandible reconstruction using grafted tissue, bone, and/or medical implants is required following the resection of such lesions. However, such grafts may not completely restore the continuity of the mandible. Facial transplantations using allografts are common, but mandibular allotransplantation has not been performed in humans, due to the unstable immune reaction of the complex tissue. In this study, mandibular transplantations performed under the effect of the immunosuppressive agent, FK506, were evaluated in dogs. MethodsMandibular allotransplantations were performed in 21 pairs of sex-blind beagle dogs. The left side of the mandible in the donor dog was transplanted to the left side of the mandible in the recipient dog. The FK506 doses were 0 mg for 3 dog pairs, 0.08 mg/kg/day for 3, 0.12 mg/kg/day for 5, 0.16 mg/kg/day for 5, and 0.32 mg/kg/day for 5 pairs. Twelve weeks after transplantation, the dogs were euthanized. Computed tomography (CT) and histological examinations of the transplanted sides were performed. ResultsSuccessful graft acceptance was dependent on immunosuppressive agent doses, and dogs administered more than 0.16 mg/kg/day FK506 showed 100 % survival. However, dogs administered 0.32 mg/kg/day FK506 showed significant weight loss 12 weeks after the surgery. CT findings showed thick mandibular cortical bone in the transplanted sites. ConclusionsThese results indicate that 0.16 mg/kg/day FK506 was the ideal dose for allotransplantations. Bone hyperplasia was observed in the transplanted sides, but it is not a disadvantage for allotransplantations.