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The adhesion of platelet cells is viewed as a first step in thrombus formation, and cancer cell attachment can lead to cancer seeding. In this study, we examined the feasibility of utilizing Zr53Cu33Al9Ta5 thin film metallic glass (TFMG) to minimize the adhesion of human cancer cells (breast cancer cell, colon cancer cell, and esophageal cancer cell), human and animal platelets. TFMG and pure titanium (Ti) were respectively grown on glass substrates to a thickness of 200 nm using magnetron sputtering. TFMG was shown to reduce surface roughness of approximately 27% than Ti coating did on glass samples. The concentrations of all major ions released from the TFMG were well below toxic levels. TFMG surfaces were more effective than Ti in increasing the contact angle of water, phosphate buffer saline (PBS) and blood from different animal species. The application of TFMG to bare surfaces was shown to reduce the attachment area of human platelets by 77% and that of pig platelets by 63%. TFMG also reduced the attachment of cancer cells by up to ~87%. These characteristics can be attributed to a low surface free energy of TFMG-coated surfaces (31.89 mN/m), which is far below that of Ti-coated (39.25 mN/m) and bare glass (47.80 mN/m). These findings demonstrate the considerable potential of TFMG coatings in the fabrication of medical instruments aimed at preventing the adhesion of platelet and cancer cells.

In this study, we fabricated first-ever metallic glass nanotubes (MGNTs) in a distinct pattern on a Si substrate, by sputter-depositing a coating of metallic glass (Zr55Cu30Al10Ni5) over a contact-hole array template created in photoresist. The resulting nanotubes were 500 or 750 nm in height with a diameter of 500 or 750 nm and wall thickness ranging from 44 nm to 103 nm. The structure of the nanotubes was preserved by the high strength and ductility of the metallic glass during the removal of the photoresist template under ultrasonic vibration. We observed an increase in the hydrophobicity of the MGNT with an increase in the thickness of the walls, with the thickest walls presenting an apparent contact angle of 139°. The hydrophobicity is due to air trapped within the tubes, which prevents the intrusion of water into the nanostructures. We also observed thermal-response behavior on the surface of the MGNT array. Surface cooling produced negative pressure within the nanochambers, which created a sucking force against the water droplets. Surface heating produced positive pressure within the nanochambers, which actually lifted the droplets. This thermal-response behavior was shown to be reversible for at least five cycles between 25 and 55 °C. The MGNT created adhesion forces reaching 14.2 N cm−2, which was sufficient to secure the water droplets even when the surface was tilted or completely inverted. The MGNT array in this study represents a biomimetic analog with switchable contact interface, the behavior of which can be controlled simply by altering the surface temperature.

The concurrent attachment and detachment movements of geckos on virtually any type of surface via their foot pads have inspired us to develop a thermal device with numerous arrangements of a multi-layer thin film together with electrodes that can help modify the temperature of the surface via application of a voltage. A sequential fabrication process was employed on a large-scale integration to generate well-defined contact hole arrays of photoresist for use as templates on the electrode-based device. The photoresist templates were then subjected to sputter deposition of the metallic glass Zr55Cu30Al10Ni5. Consequently, a metallic glass nanotube (MGNT) array having a nominal wall thickness of 100 nm was obtained after removal of the photoresist template. When a water droplet was placed on the MGNT array, close nanochambers of metallic glass were formed. By applying voltage, the surface was heated to increase the pressure inside the nanochambers; this generated an expanding force that raised the droplet; thus, the static water contact angle (SWCA) was increased. In contrast, a sucking force was generated during surface cooling, which decreased the SWCA. Our fabrication strategy exploits the MGNT array surface as nanosuckers, which can mimic the climbing aptitude of geckos as they attach to (>10 N m−2) and detach from (0.26 N m−2) surfaces at 0.5 and 3 V of applied voltage, respectively. Thus, the climbing aptitude of geckos can be mimicked by employing the processing strategy presented herein for the development of artificial foot pads.

Main-group element-containing mixed-metal carbonyl complexes represent an important field of contemporary chemistry. This account will focus on the development of Cu-incorporated group 8 (Ru or Fe) carbonyl chalcogenide complexes, and will represent a review and discussion, mainly from our group and others, of the rational synthetic methodologies, controlled cluster-growth processes, transformations, as well as their special applications in areas of semiconductors and catalysis. The description of this review is arranged by four types of building blocks, ERu 5 -, Te 2 Ru 4 Cu 2 -, EFe 3 -, and TeFe 3 Cu 2 -based (E = Te, Se, S) carbonyl clusters, which can further react with copper sources, CuX (X = Cl, Br, I) and [Cu(MeCN) 4 ][BF 4 ], or toward inorganic and organic reagents to construct the ternary E‒M‒Cu‒CO (M = Ru, Fe) complexes or polymers. The NHC-decorated TeFe 3 Cu 2 -based complexes exhibited pronounced catalytic activities toward the homocoupling of arylboronic acids with low copper loadings and high yields. Further, the energy gaps of these ternary carbonyl complexes were systematically studied in terms of chalcogen and halide effects, and most importantly, the size and dimensionality of these complexes.

The formation of a hitherto unknown 4-center, 6π-conjugated trigonal-planar complex, [Bi{Cr(CO)5}3]- (1), is reported, in which the oxidation state of the Bi atom is +3, as evidenced by XAS, XPS, and DFT calculations. The BiIII atom in 1 has dual donor and acceptor properties in its bonding mode. In contrast to the mild Lewis acidity of BiIII, the central Bi in 1 functions as a prodigious Lewis acid site to exhibit strong affinity toward F- ion, unique solvatochromic properties, intriguing etherification, via the C-O bond cleavage of alcohols, and surprising semiconducting characteristics with an ultra-narrow optical band gap of 1.02 eV, which can be attributed to the intermolecular Bi···O and O···O interactions in the solid state. The tetrahedral Fe(CO)4-adduct [{Fe(CO)4}Bi{Cr(CO)5}3]3- (1-Fe) allowed the selective demetallation to afford the isoelectronic multiply bonded BiCr3-complex 1 and the BiCr2Fe-complex, [Bi{Cr(CO)5}2{Fe(CO)4}]- (2), which may open a novel pathway for the design of the heterometal-incorporated trigonal-planar Bi-Cr complexes.

A coating of the Zr-based thin-film metallic glass (TFMG) was deposited on the Zr 50 Cu 30 Al 10 Ni 10 bulk metallic glass (BMG) to investigate shear-band evolution under four-point-bend fatigue testing. The fatigue endurance-limit of the TFMG-coated samples is ~ 33% higher than that of the BMG. The results of finite-element modeling (FEM) revealed a delay in the shear-band nucleation and propagation in TFMG-coated samples under applied cyclic-loading. The FEM study of spherical indentation showed that the redistribution of stress by the TFMG coating prevents localized shear-banding in the BMG substrate. The enhanced fatigue characteristics of the BMG substrates can be attributed to the TFMG coatings retarding shear-band initiation at defects on the surface of the BMG.

We have used nanoindentation to investigate mechanical properties of 200-nm-thick amorphous multilayer consisting of alternating layers of Zr-based thin film metallic glass (TFMG) and holmium scandium oxide (HSO). Nanoindentation results show that TFMG/HSO multilayer exhibits the high hardness and Young's modulus. Owing to its high hardness, smooth surface, and good adhesion properties, TFMG/HSO multilayer is then employed as a protective coating to improve the four-point bending fatigue properties of 316L stainless steel. With coating, the fatigue life is increased from 2.4×10 5 to 4.9×10 6 cycles, at the stress of 700 MPa. A crack retardation mechanism has been proposed to explain the role of TFMG/HSO multilayer in improving fatigue properties of 316L stainless steel substrate.

Effects of various surface modifications on four-point bending property improvements of Zr55Cu30Al10Ni5 bulk metallic glass (BMG) are systematically studied. Surface modifications investigated include thin-film metallic glass coating, artificial scratches and femtosecond laser patterning. After modifications, the negligible plastic strain of 3-mm-thick BMG is found to markedly enhance to ~9.2%, without sacrificing its extraordinary strength. Instead, bending yield and fracture strengths in the surface-modified samples are increased to ~2.8 GPa and ~4.0 GPa, respectively, corresponding to a rise of ~66% from those of as-cast samples. In addition, the samples with surface modifications exhibit distinct shear band morphologies. Relationships between the shear band offset, shear band spacing and plastic strain of bent BMG samples are established. Our experimental results demonstrate that BMG is able to survive plastic flow without abrupt fracture through proper designs of surface modifications, in which large numbers of shear bands are formed to distribute the strain effectively upon loading.

Thin film metallic glass (TFMG) is a new class of metallic thin film with unique characteristics, including smooth surface, absence of grain boundaries, second-order glass transition, annealing-induced amorphization, soft magnetic properties, and high thermal stability. Hence, with these properties, TFMGs are found very useful and promising in many areas, ranging from structural, biomedical to electrical components. This review provides an update on future challenges and opportunities associated with the further development of TFMG.

article i nfo Annealing-inducedindentationrecovery behavioursofsputteredZr50Cu28Al14Ni8,Cu48Zr42Al6Ti4,Hf46Cu45Al6Ti3, and Fe65Ti13Co8Ni7B6Nb1 (in at. %) thin film metallic glasses (TFMGs) on silicon substrate are examined. Influ- ences of indenter tip geometry, film thickness and film composition on indentation recovery of TFMGs have been studied. Nanoindentations are performed at room temperature with two three-sided pyramidal indenters (Berkovich and cube-corner), followed by annealing performed within the supercooled liquid temperatures. The results reveal that the extent of recovery of indentation by Berkovich indenter is higher than that of cube-corner owing to highercompressive stress underneath the Berkovich tip and largerradius of curvature of the indent left behind after Berkovich indentation. The numerical modelling of depth profile of Zr-based TFMG shows the blunter the indenter tip is the higher the recovery. The thicker film also shows larger recovery. In addition, because of the difference in bonding force among constituent elements, Zr-based TFMG exhibits larger recovery than Cu-, Hf- and Fe-based TFMGs.

The thermal stability of joints in thermoelectric (TE) modules, which are degraded during interdiffusion between the TE material and the contacting metal, needs to be addressed in order to utilize TE technology for competitive, sustainable energy applications. Herein, we deposit a 200 nm-thick Zr-based thin-film metallic glass (TFMG), which acts as an effective diffusion barrier layer with low electrical contact resistivity, on a high-zT Se-doped AgSbTe2 substrate. The reaction couples structured with TFMG/TE are annealed at 673 K for 8–360 hours and analyzed by electron microscopy. No observable IMCs (intermetallic compounds) are formed at the TFMG/TE interface, suggesting the effective inhibition of atomic diffusion that may be attributed to the grain-boundary-free structure of TFMG. The minor amount of Se acts as a tracer species, and a homogeneous Se-rich region is found nearing the TFMG/TE interface, which guarantees satisfactory bonding at the joint. The diffusion of Se, which has the smallest atomic volume of all the elements from the TE substrate, is found to follow Fick’s second law. The calculated diffusivity (D) of Se in TFMG falls in the range of D~10−20–10−23(m2/s), which is 106~107 and 1012~1013 times smaller than those of Ni [10−14–10−17(m2/s)] and Cu [10−8–10−11(m2/s)] in Bi2Te3, respectively.

The thermal stability of joints in thermoelectric (TE) modules, which are degraded during interdiffusion between the TE material and the contacting metal, needs to be addressed in order to utilize TE technology for competitive, sustainable energy applications. Herein, we deposit a 200 nm-thick Zr-based thin-film metallic glass (TFMG), which acts as an effective diffusion barrier layer with low electrical contact resistivity, on a high-zT Se-doped AgSbTe2 substrate. The reaction couples structured with TFMG/TE are annealed at 673 K for 8–360 hours and analyzed by electron microscopy. No observable IMCs (intermetallic compounds) are formed at the TFMG/TE interface, suggesting the effective inhibition of atomic diffusion that may be attributed to the grain-boundary-free structure of TFMG. The minor amount of Se acts as a tracer species, and a homogeneous Se-rich region is found nearing the TFMG/TE interface, which guarantees satisfactory bonding at the joint. The diffusion of Se, which has the smallest atomic volume of all the elements from the TE substrate, is found to follow Fick’s second law. The calculated diffusivity (D) of Se in TFMG falls in the range of D~10−20–10−23(m2/s), which is 106~107 and 1012~1013 times smaller than those of Ni [10−14–10−17(m2/s)] and Cu [10−8–10−11(m2/s)] in Bi2Te3, respectively.

In this study, we assessed the fibrinogen and albumin adsorption performance of Ni-free Zr-based (Zr53Cu33Al9Ta5) thin-film metallic glass (TFMG). Quartz crystal microbalance (QCM) system and fluorescence spectrophotometer were used to obtain protein adsorption measurements, using two different substrates (QCM and glass). Test samples were fabricated by coating both of the substrates with TFMG and Ti (widely used in implants) for comparison. In dynamic QCM as well as static fluorescence spectrophotometer tests, the TFMG achieved a lower fibrinogen to albumin adsorption ratio. The TFMG coating also exhibited high hydrophobicity (water contact angle of 96°) with low surface roughness of 1.06 nm and surface free energy of 35.3 mN/m. This is a clear demonstration of the excellent hemocompatibility of Ni-free Zr-based TFMG.

In this study, we assessed the characteristics of thin film metallic glass (TFMG)-coated needles by inserting them into polyurethane rubber blocks and porcine skin with underlying fat and muscle. The insertion of TFMG-coated needles was shown to reduce the fracture toughness of the porcine tissue and polyurethane rubber by ~24%, compared to the bare needles. In the pierce-through experiments performed on 3.3 mm-thick test samples, the coated needles required ~27% less time to reach the peak force when applied to rubber samples and ~14% less time when applied to porcine tissue. The reason for the low resistance to fracturing was elucidated by using an optical microscope to examine the area of the hole created by the first insertion of the needle. The area of the hole created by the TFMG-coated needle was ~44% smaller than that created by the bare needle, indicating less damage to the testing materials. Overall, the TFMG-coated needles were associated with lower cutting forces, frictional forces, and resistance to insertion.

The thin film metallic glass (TFMG) is an effective diffusion barrier layer for PbTe-based thermoelectric (TE) modules. Reaction couples structured with Cu/TFMG/PbTe are prepared via sputter-deposition and are annealed at 673 K for 8-96 h. The transmission line method is adopted for the assessment of electrical contact resistivity upon the PbTe/TFMG, and the value remains in the range of 3.3-2.5 × 10−9 (Ω m2). The titanium-based TFMG remains amorphous upon annealing at 673 K for 48 h and effectively blocks the inter-diffusion by not having grain-boundaries, which only allows the bulk diffusion between the metal electrode and the TE substrate.

Summary The bending of aquitard like a plate due to aquifer pumping and compression is often encountered in many practical problems of subsurface flow. This reaction will have large influence on the release of the volume of water from the aquifer, which is essential for the planning and management of groundwater resources in aquifers. However, the groundwater flow induced by pumping in a leaky aquifer system is often assumed that the total stress of aquifer maintains constant all the time and the mechanical behavior of the aquitard formation is negligible. Therefore, this paper devotes to the investigation of the effect of aquitard bending on the drawdown distribution in a leaky aquifer system, which is obviously of interest in groundwater hydrology. Based on the work of Wang et al. (2004) this study develops a mathematical model for investigating the impacts of aquitard bending and leakage rate on the drawdown of the confined aquifer due to a constant-rate pumping in the leaky aquifer system. This model contains three equations; two flow equations delineate the transient drawdown distributions in the aquitard and the confined aquifer, while the other describes the vertical displacement in response to the aquitard bending. For the case of no aquitard bending, this new solution can reduce to the Hantush Laplace-domain solution ( Hantush, 1960 ). On the other hand, this solution without the leakage effect can reduce to the time domain solution of Wang et al. (2004) . The results show that the aquifer drawdown is influenced by the bending effect at early time and by the leakage effect at late time. The results of sensitivity analysis indicate that the aquifer compaction is sensitive only at early time, causing less amount of water released from the pumped aquifer than that predicted by the traditional groundwater theory. The dimensionless drawdown is rather sensitive to aquitard’s hydraulic conductivity at late time. Additionally, both the hydraulic conductivity and thickness of the aquifer are the most sensitive parameters in influencing the predicted dimensionless drawdown.

Lean-burn gasoline and diesel automobiles can have superior fuel efficiency but require advanced DeNO x technology. For a catalytic converter to be put underneath the passenger cars, it must be compact enough. Effective automotive DeNO x treatment should start at ambient temperature to avoid a heating period when the pollutant cannot be effectively treated. An electro-catalytic honeycomb, composed of electro-catalytic tubes, would fulfill this size requirement. This work demonstrates that effective lean DeNO x can be performed at ambient temperature by an electro-catalytic tube. The DeNO x activity is relatively insensitive to the variation of temperature from 200 to 600 °C and increases slightly when temperature decreases from 200 °C to ambient, but is quite sensitive to that of either the oxygen concentration or the NO x concentration. When the oxygen concentration and the NO x concentration increase from 0.5 to 14% and from 250 to 3800 ppm, respectively, the DeNO x activities increase considerably. The NO conversion also increases with decreasing NO x concentration below 250 ppm, when there is zero NO 2 yield; these can result in zero NO x emission.

This paper reports on the use of Zr-based (Zr53Cu33Al9Ta5) thin film metallic glass (TFMG) for the coating of syringe needles and compares the results with those obtained using titanium nitride and pure titanium coatings. TFMG coatings were shown to reduce insertion forces by ∼66% and retraction forces by ∼72%, when tested using polyurethane rubber block. The benefits of TFMG-coated needles were also observed when tested using muscle tissue from pigs. In nano-scratch tests, the TFMG coatings achieved a coefficient of friction (COF) of just ∼0.05, which is about one order of magnitude lower than those of other coatings. Finite-element modeling also indicates a significant reduction in injection and retraction forces. The COF can be attributed to the absence of grain boundaries in the TFMG coating as well as a smooth surface morphology and low surface free energy.

Lean-burn gasoline and diesel engines can offer high fuel efficiency for automobiles. However, a highly fuel-efficient automotive engine produces an exhaust with high NOx concentration and current technologies cannot treat or have difficulty to treat it; therefore, advanced NOx emission control technology is needed. We demonstrated that electro-catalytic honeycomb cells are effective for lean-burn NOx emission control by direct NOx decomposition, without consuming reductant or electricity. This can be explained by facile oxygen desorption driven by self-generated electromotive force (emf). NOx was converted effectively to nitrogen and oxygen starting at ambient temperature; there is no need to heat the cells and thus no delay on DeNOx treatment. Increasing oxygen concentration enhances the DeNOx activity. NOx of very high concentration is preferred. Zero NOx emission can be achieved. Automotive engines can thus be operated with high fuel efficiency to contribute to the reduction of the greenhouse gases and also zero pollution. These self-emf-driven honeycomb cells can be composed to be a honeycomb monolith in a size similar to that of three-way catalytic converter and can thus be used for lean-burn gasoline and diesel passenger cars.

A new type of TeFe3(CO)9-incorporated dicopper NHC complex was obtained directly from one-pot reactions. By the introduction of the cluster anion [TeFe3(CO)9](2-) and NHCs as the ligands, these di-Cu(i)-based complexes exhibited pronounced catalytic activities toward the homocoupling of arylboronic acids with low Cu loadings and high yields (up to 98%).

Nitric oxide (NO) is a highly reactive, membrane-permeable free radical, which has recently emerged as an important antioxidant. Here we investigated the protective effect of NO against the toxicity and NH4+ accumulation in rice leaves caused by excess CuSO4 (10mmol L(-1)). It was found that free radical scavengers (sodium benzoate, thiourea, and reduced glutathione) reduced the toxicity and NH4+ accumulation in rice leaves caused by excess CuSO4. NO donor sodium nitroprusside (SNP) was also effective in reducing CuSO4-induced toxicity and NH4+ accumulation in rice leaves. The protective effect of SNP on the toxicity and NH4+ accumulation can be reversed by 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, suggesting that the protective effect of SNP is attributable to NO released. Results obtained in the present study suggest that reduction of CuSO4-induced toxicity and NH4+ accumulation by SNP is most likely mediated through its ability to scavenge active oxygen species.

We report the first example of room-temperature rubber-like deformation in thin-film metallic glasses (TFMGs), 260-nm-thick Zr60Cu24Al11Ni5 layers, under ultra-high shear strain. The TFMGs were deposited, with no external heating, on Zr-based bulk metallic glass (BMG) and Si(001) substrates by rf magnetron sputtering in a 3 mTorr Ar plasma. Cross-sectional transmission electron microscopy (XTEM) analyses and nanoindentation results reveal that the TFMGs undergo an incredibly large shear strain, estimated to be ∼4000%, during fatigue tests, and thickness reductions of up to 61.5%, with no shear-banding or cracking, during extreme nanoindentation experiments extending through the film and into the substrate. TFMG/BMG samples also exhibit film/substrate diffusion bonding during deformation as shown by high-resolution XTEM.