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Irradiating a small capsule containing deuterium and tritium fuel directly with intense laser light causes it to implode, which creates a plasma hot enough to initiate fusion reactions between the fuel nuclei. Here we report on such laser direct-drive experiments and observe that the fusion reactions produce more energy than the amount of energy in the central so-called hot-spot plasma. This condition is identified as having a hot-spot fuel gain greater than unity. A hot-spot fuel gain of around four was previously accomplished at the National Ignition Facility in indirect-drive inertial confinement fusion experiments where the capsule is irradiated by X-rays. In that case, up to 1.9 MJ of laser energy was used, but in contrast, our experiments on the OMEGA laser system require as little as 28 kJ. As the hot-spot fuel gain is predicted to grow with laser energy and target size, our work establishes the direct-drive approach to inertial fusion as a promising path towards burning and ignited plasmas in the laboratory. Additionally, we report a record (direct-drive) fusion yield of 0.9 kJ on OMEGA, which we achieved with thin-ice deuterium–tritium liner targets.

Focussing laser light onto the surface of a small target filled with deuterium and tritium implodes it and leads to the creation of a hot and dense plasma, in which thermonuclear fusion reactions occur. In order for the plasma to become self-sustaining, the heating of the plasma must be dominated by the energy provided by the fusion reactions—a condition known as a burning plasma. A metric for this is the generalized Lawson parameter, where values above around 0.8 imply a burning plasma. Here, we report on hydro-equivalent scaling of experimental results on the OMEGA laser system and show that these have achieved core conditions that reach a burning plasma when the central part of the plasma, the hotspot, is scaled in size by at least a factor of 3.9 ± 0.10, which would require a driver laser energy of at least 1.7 ± 0.13 MJ. In addition, we hydro-equivalently scale the results to the 2.15 MJ of laser energy available at the National Ignition Facility and find that these implosions reach 86% of the Lawson parameter required for ignition. Our results support direct-drive inertial confinement fusion as a credible approach for achieving thermonuclear ignition and net energy in laser fusion.

Variable cross-section beams are widely applied in engineering fields for their appropriate distribution of mass and strength. However, the free-vibration characteristics are difficult to study by analytical method because the governing equation of the nonuniform beam has varying flexural stiffness and distributed mass. In this work, the asymptotic perturbation method is introduced to study the free vibration of variable width beams. To deal with the ordinary differential equation with variable coefficients, based on the asymptotic perturbation method, the equivalent frequency equation of the uniform beam is obtained to give frequency correction of the considered beam structure by analyzing the first-order terms. The finite-element method and vibration experiment are also conducted to validate the theoretical analysis results. Concise and accurate frequency equations were derived based on the asymptotic perturbation method. The effects of the width ratio on the frequencies are illustrated and discussed. It shows a good agreement by comparing the analytical solutions, finite-element analysis results, and experimental results. In addition, it is observed that the natural frequency reduces with the increase of the width ratio. The asymptotic perturbation method is simple and efficient and can be used to conveniently analyze the free vibration of variable width beams, moreover, it could be extended to analyze the free vibration of any other nonuniform beam structures.

Theoretically, magnetic reconnection—the process responsible for solar flares and magnetospheric substorms—occurs at the X‐line or radial null in the electron diffusion region (EDR). However, whether this theory is correct is unknown, because the radial null (X‐line) has never been observed inside the EDR due to the lack of efficient techniques and the scarcity of EDR measurements. Here we report such evidence, using data from the recent MMS mission and the newly developed First‐Order Taylor Expansion (FOTE) Expansion technique. We investigate 12 EDR candidates at the Earth's magnetopause and find radial nulls (X‐lines) in all of them. In some events, spacecraft are only 3 km (one electron inertial length) away from the null. We reconstruct the magnetic topology of these nulls and find it agrees well with theoretical models. These nulls, as reconstructed for the first time inside the EDR by the FOTE technique, indicate that the EDR is active and the reconnection process is ongoing. Magnetic reconnection is a key process responsible for many explosive phenomena in nature such as solar flares and magnetospheric substorms. Theoretically, such process occurs at the X‐line or radial null in the electron diffusion region (EDR). However, whether this theory is correct is still unknown, because the radial null (X‐line) has never been observed inside the EDR due to the lack of efficient technique and the scarcity of EDR measurements. Here we report such evidence, using data from the recent MMS mission and the newly developed FOTE technique. We provide the first evidence of radial nulls (X‐lines) in EDR

Focusing laser light onto a very small target can produce the conditions for laboratory-scale nuclear fusion of hydrogen isotopes. The lack of accurate predictive models, which are essential for the design of high-performance laser-fusion experiments, is a major obstacle to achieving thermonuclear ignition. Here we report a statistical approach that was used to design and quantitatively predict the results of implosions of solid deuterium–tritium targets carried out with the 30-kilojoule OMEGA laser system, leading to tripling of the fusion yield to its highest value so far for direct-drive laser fusion. When scaled to the laser energies of the National Ignition Facility (1.9 megajoules), these targets are predicted to produce a fusion energy output of about 500 kilojoules—several times larger than the fusion yields currently achieved at that facility. This approach could guide the exploration of the vast parameter space of thermonuclear ignition conditions and enhance our understanding of laser-fusion physics.

Wheat kernel morphology is a very important trait for wheat yield improvement. This is the first report of association analysis of kernel morphology traits in wheat breeding lines. In Qinghai, China, the research described here involved genome-wide association analysis in breeding lines derived from synthetic hexaploid wheat with a mixed linear model to identify the quantitative trait loci (QTLs) related to kernel morphology. The 8033 effective Diversity Array Technology (DArT) markers produced a genetic map of 5901.84 cM with an average density of 1.36 markers/cM. Population structure analysis classified 507 breeding lines into three groups by Bayesian structure analysis using unlinked markers. Linkage disequilibrium decay was observed with a map coverage of 2.78 cM. Marker-trait association analysis showed that 15 DArT markers for kernel morphology were detected, located on nine chromosomes, and explained 2.6%–4.0% of the phenotypic variation of kernel area (KA), kernel width (KW), kernel length (KL) and thousand-kernel weight (TKW). The marker 1139297 was related to both the KL and KA traits. Only six DArT markers were close to known QTLs. The parent SHW-L1 carried eight favored alleles, while other seven favored alleles were derived from elite common wheat cultivars. These QTLs, identified in elite breeding lines, should help us understand the kernel morphology trait better, and to provide germ-plasm for breeding new wheat cultivars for Qinghai Province or other regions.

The impact of adding leukotriene receptor antagonists (LTRAs) to antihistamines for chronic urticaria (CU) is unclear, leading to a lack of definitive guidance. We systematically reviewed and meta-analyzed the use of add-on LTRAs for CU.

AbstractThe goal of the National Direct-Drive Program is to demonstrate and understand the physics of laser direct drive (LDD). Efforts are underway on OMEGA for the 100-Gbar Campaign to demonstrate and understand the physics for hot-spot conditions and formation relevant for ignition at the 1-MJ scale, and on the National Ignition Facility to develop an understanding of the direct-drive physics at long scale lengths for the MJ Direct-Drive Campaign. The strategy of the National Direct-Drive Program is described; the requirements for the deuterium-tritium cryogenic fill-tube target being developed for OMEGA are presented; and preliminary LDD implosion measurements of hydrodynamic mixing seeded by laser imprint, the target-mounting stalk, and microscopic surface debris are reported.

ABSTRACTA novel rare earth (RE)-salt bath nitriding of TC21-DT titanium alloy was primarily developed by adding certain amount of RE cerium oxide (CeO2) in KNO3and NaNO3salt bath, heated to temperatures in the range 590–650°C for periods up to 5 h in an ambient furnace atmosphere. The results showed that Ti phases and titanium nitride phase were formed on the surface of RE added samples; while no titanium nitride phases formed on the surface of conventional one, without RE addition. Furthermore, the surface hardness of nitrided samples, incorporated with RE addition, was about two times higher than that of conventional one (340HV0.01). The main improvement mechanism was analysed as well.

Using MMS high‐resolution measurements, we present the first observation of fast electron jet (Ve~2,000 km/s) at a dipolarization front (DF) in the magnetotail plasma sheet. This jet, with scale comparable to the DF thickness (~ 0.9 di), is primarily in the tangential plane to the DF current sheet and mainly undergoes the E× Bdrift motion; it contributes significantly to the current system at the DF, including a localized ring‐current that can modify the DF topology. Associated with this fast jet, we observed a persistent normal electric field, strong lower hybrid drift waves, and strong energy conversion at the DF. Such strong energy conversion is primarily attributed to the electron‐jet‐driven current (E ⋅ je≈ 2 E ⋅ ji), rather than the ion current suggested in previous studies. For the first time, fast electron jet is observed at dipolarization frontThis jet is responsible for current and energy conversion at dipolarization frontQuantitatively, the partition of energy conversion is E ⋅ je≈ 2 E ⋅ ji

With high‐resolution data of the recently launched Magnetospheric Multiscale mission, we report a magnetic reconnection event at the dayside magnetopause. This reconnection event, having a density asymmetry Nhigh/Nlow≈ 2 on the two sides of the reconnecting current sheet and a guide field Bg≈ 0.4B0in the “out‐of‐plane” direction, exhibit all the two‐fluid features: Alfvenic plasma jets in the outflow region, bipolar Hall electric fields toward the current sheet center, quadrupolar Hall magnetic fields in the “out‐of‐plane” direction, and the corresponding Hall currents. Obviously, the density asymmetry Nhigh/Nlow≈ 2 and the guide field Bg≈ 0.4B0are not sufficient to dismiss the quadrupolar pattern of Hall reconnection. This is different from previous simulations, where the bipolar pattern of Hall reconnection was suggested. Asymmetric guide‐field reconnection is observed at the magnetopauseThis reconnection is characterized by Hall pattern and Alfvenic plasma jetSymmetric Hall magnetic and electric fields were found in this event

Whistler waves that can produce anomalous resistivity by affecting electrons' motion have been suggested as one of the mechanisms responsible for magnetic reconnection in the electron diffusion region (EDR). Such type of waves, however, has rarely been observed inside the EDR so far. In this study, we report such an observation by Magnetospheric Multiscale (MMS) mission. We find large-amplitude whistler waves propagating away from the X line with a very small wave-normal angle. These waves are probably generated by the perpendicular temperature anisotropy of the ~300 eV electrons inside the EDR, according to our analysis of dispersion relation and cyclotron resonance condition; they significantly affect the electron-scale dynamics of magnetic reconnection and thus support previous simulations. Whistler waves are observed inside the EDR by MMSThe whistlers are propagating away from the X lineThe pancake distribution of electrons in the EDR generates the whistlers

Coral reefs have suffered remarkable declines worldwide. Nutrient overenrichment is considered to be one of the primary local causes. The Luhuitou fringing reef in southern China is a well-known tourist destination that is subject to enormous coastal renovation. The mean d13C, d15N value, and carbon over nitrogen ratio (C/N) of particulate organic matter were -21.56?±?1.94‰, 7.04?±?3.81‰, and 5.81?±?1.86, respectively, suggesting mixed sources of carbon and nitrogen. The IsoError calculations suggested that marine phytoplankton and marine benthic algae dominated the majority of carbon sources, while anthropogenic and terrestrial organic nitrogen dominated the nitrogen sources. A tendency toward greater terrestrial detritus and anthropogenic-derived discharges was found during dry seasons and greater marine-derived organic matter during wet seasons. These results demonstrated the existence of anthropogenic influences and high dissolved inorganic nitrogen concentrations and C/N ratios. Anthropogenic nutrient discharge moderated nitrogen limitation, whereas phosphorus became more important to the reef ecosystem. Despite the marine carbon sources dominated, freshwater and terrestrial-derived organic carbon sources were also very important. Meanwhile, anthropogenic and terrestrial organic nitrogen sources were dominant. Therefore, pollution from more extensive region and anthropogenic activities from riverine sewage discharges adjacent to reefs should be focused to effectively reduce human-derived nutrients on reefs. Isotopic values revealed strong anthropogenic influences on coral reefsHydrodynamic conditions coupled with human activities have profound implications for nutrient concentrationsThere might be more inputs from terrestrial detritus and anthropogenic-derived discharges in dry seasons

Cancer-associated fibroblasts have been shown to inhibit or stimulate tumor growth depending on stage, grade, and tumor type. It remains unclear, however, the effect of endometrial-cancer-associated fibroblasts on hormone-driven responses in endometrial cancer. In this study, we investigated the effect of normal and cancer-associated stromal cells from patients with and without endometrial cancer on endometrial tumor growth in response to estradiol (E2) and progesterone (P4). Compared to benign endometrial stromal cells, the low-grade and high-grade cancer-associated stromal cells exhibited a blunted hormone response for proliferation as well as IGFBP1 secretion. Additional analysis of the influence of stromal cells on hormone-driven tumor growth was done by mixing stromal cells from benign, low-grade, or high-grade tumors, with Ishikawa cells for subcutaneous tumor formation. The presence of both benign and high-grade cancer-associated stromal cells increased estradiol-driven xenografted tumor growth compared to Ishikawa cells alone. Low-grade cancer-associated stromal cells did not significantly influence hormone-regulated tumor growth. Addition of P4 attenuated tumor growth in Ishikawa + benign or high-grade stromal cells, but not in Ishikawa cells alone or with low-grade stromal cells. Using an angiogenesis focused real-time array TGFA, TGFB2 and TGFBR1 and VEGFC were identified as potential candidates for hormone-influenced growth regulation of tumors in the presence of benign and high-grade stromal cells. In summary, endometrial-cancer-associated cells responded differently to in vitro hormone treatment compared to benign endometrial stromal cells. Additionally, presence of stromal cells differentially influenced hormone-driven xenograft growth in vivo depending on the disease status of the stromal cells.

Background: Beside too long delays and clinical or electrocardiographic diagnostic difficulties, one of the reasons for not having thrombolysis could be accessibility to hospital. Our objective was thus to study [...]

Background: There remains a controversy concerning the association between myocardial dysfunction diagnosed soon after acute myocardial infarction and later quality of life. We searched for correlations between criteria of myocardial [...]

Daylily or Hemerocallisspp. (Xanthorrhoeaceae) is one of the most economically important flowering crops in the world. Ploidy level of 149 genotypes both local to China and introduced from the United States and New Zealand were assessed with an outcome of 79 diploids, 22 triploids and 48 tetraploids. A large proportion of introduced cultivars were tetraploid (42%), half were diploid and the rest, 8%, were triploid. Most Chinese cultivars were diploid; only one was tetraploid. Among the 29 wild genotypes collected from the Taihang Mountain range, 13 (45%) were triploid and 16 (55%) were diploid; no tetraploids were identified. For the 31 genotypes with known ploidy, 22 matched previous counts with the rest showing a lower ploidy. As different ploidy is common in daylily, we suggest that ploidy levels should be assessed in breeding programmes for specific breeding purposes. Karyotypes of three diploid, three triploid and two tetraploid genotypes were constructed and they were assigned to ‘3A’, ‘2B’ and ‘3B’ categories based on Stebbins’ karyotype classification.

The purpose of this study is to perform numerical simulation for the design and optimization of three-dimensional magnetohydrodynamic (MHD) controlled hypersonic inlets. An airframe/propulsion integrated module was first established for a waverider-based hypersonic vehicle at design Mach number of 6. Using this generic configuration, an MHD-based technique for large-scale inlet flow control is studied at the off-designed Mach value of 8.5. The results indicate that the inlet mass flowrate can act as an optimization criterion. Using a proper value of mass flowrate, an MHD generator possessing reasonable design parameters can effectively restore the flow field shock structure, i.e. shock-on-lip condition and improves the flow field characteristics at the combustor entrance at higher Mach number than the design value. The results further reveal that the MHD effect on the flow with higher load factor helps to extract more electric power from the external MHD generator and also helps in improving the performance of the combustor entrance.

The rheological and mechanical properties of PVC-lignin blends were studied, and their alterations were investigated after lignin was treated with poly(ethyl acrylate-co-maleic anhydride). The addition of lignin changes the early rheological properties of the blend comparing with PVC control because the rigidity of lignin particles leads to more intensive shearing in the system, but has little effect on its rheology during the equilibrium period. The processing stability slightly decreases with the increase of lignin content in the blend. The mechanical properties of the blends are worse than that of PVC control. The rheological properties of the blends are little influenced after lignin is treated with polyacrylate, but the mechanical properties, especially toughness, are improved, and the maximum impact strength is 37.7% higher than that of PVC control.

Due to the inertness of the intrinsic (nondoped) amorphous SiC (i-aSiC) material to the chemical impact, for making it porous by the electrochemical etching method, one must use the electrolyte solution with an appropriate composition. For this purpose we have found that besides the use of solutions containing surface activation agent (Triton X-100 for example), one can use also solutions containing oxidation agent. In this report we present the results obtained with electrolyte solution in which H2O2 plays the role of oxidation agent. Results showed that with appropriate ratio of components in the HF/H2O/H2O2 solution, we can manufacture a porous layer in the i-aSiC thin film with the porosity similar to the porosity of the porous layer obtained by etching in the HF/H2O/Triton X-100 solution with optimal composition. Thin film of i-aSiC material with porous surface layer can be used in different types of sensors.

The electrode of Co3O4nanowire arrays directly grown on nickel foam is prepared viaa facile one‐step method. The electrode is characterised by scanning and transmission electron microscopy and tested as the cathode of an Al–H2O2semi‐fuel cell. We found that Co3O4forms clusters of nanowires with length up to around 15 μm and diameter around 250 nm. The nanowire is composed of interconnected nanoparticles. Effects of H2O2concentrations, catholyte KOH concentration, catholyte flow rate and operation temperature on the cell performance are investigated. The cell exhibited an open circuit voltage of 1.4 V, and peak power densities of 85 and 137 mW cm–2at 25 and 65 °C, respectively, while running on 0.4 mol L–1H2O2at a flow rate of 80 mL min–1.

The aim of this study was to induce up-regulation of the dystrophin-related gene UTRNthat encodes the protein utrophin, to determine whether this could compensate for the lack of dystrophin function in Duchenne muscular dystrophy. The human UTRNpromoter, which contains two putative binding sites for homeobox protein engrailed-1 (EN1), was analysed. It was found that EN1 binding site 2 in the UTRNgene promoter directly interacted with transcription factor EN1 in vitro. Chromatin immunoprecipitation assays of the EN1–UTRNpromoter complex from rhabdomyosarcoma and HeLa cell lines confirmed that endogenous EN1 interacted with this region in vivo. The findings suggest that EN1 directly interacts with the UTRNpromoter. Small interfering RNA was used to inhibit EN1gene expression. Higher utrophin mRNA levels were observed in EN1-inhibited cells compared with controls. The increase in utrophin mRNA in rhabdomyosarcoma cells and HeLa cells may have resulted from inhibition of EN1expression.

The fluid film force model plays a very important role in the non-linear dynamic analysis of a rotor-bearing system. Based on the assumption of the short journal bearing, the fluid film pressure distribution in an elliptical bearing is obtained in terms of the Reynolds equation and the dynamic Gümbel boundary conditions. According to the structural characteristic of elliptical bearing and the integral of fluid film pressure distribution, the fluid force model is formulated. A numerical experiment on the Jeffcott flexible-rotor model is given to show that the model is effective when length-diameter ratio is smaller than 0.6, and the computing cost for dynamical response of rotor-bearing is reduced. Finally, the dynamical behaviour and bifurcation of a 200 MW turbine set are numerically obtained applying the new fluid film force model.

Three novel dialkyl disulfonate gemini surfactants (Cn-6-Cn, n = 6, 8, 12; n is carbon number of hydrophobic chain) were synthesized from cyanuric chloride, aliphatic amine and taurine. The chemical structures of the prepared compounds were confirmed by 1H NMR, 13C NMR, IR spectra and ESI-MS. Their critical micelle concentrations (CMC) in the aqueous solutions at 25°C were determined by surface-tension method. With the increasing length of the hydrophobic carbon chain, the values of their CMC decreased. The surface tension measurements of Cn-6-Cngive low CMC, great efficiency in lowering the surface tension, and strong adsorption at air–water interface. In addition, adsorption and micellization behavior of Cn-6-Cnwere estimated by the parameter of pC20, the minimum average area per surfactant molecule (Amin).

Abstract: We introduce a novel clustering algorithm named GAKREM (Genetic Algorithm K-means Logarithmic Regression Expectation Maximization) that combines the best characteristics of the K-means and EM algorithms but avoids their weaknesses such as the need to specify a priori the number of clusters, termination in local optima, and lengthy computations. To achieve these goals, genetic algorithms for estimating parameters and initializing starting points for the EM are used first. Second, the log-likelihood of each configuration of parameters and the number of clusters resulting from the EM is used as the fitness value for each chromosome in the population. The novelty of GAKREM is that in each evolving generation it efficiently approximates the log-likelihood for each chromosome using logarithmic regression instead of running the conventional EM algorithm until its convergence. Another novelty is the use of K-means to initially assign data points to clusters. The algorithm is evaluated by comparing its performance with the conventional EM algorithm, the K-means algorithm, and the likelihood cross-validation technique on several datasets. [Copyright &y& Elsevier]

Using a unique microarray platform for cytosine methylation profiling, the DNA methylation landscape of the human genome was monitored at more than 21 000 sites, including 79% of the annotated transcriptional start sites (TSS). Analysis of an oligodendroglioma derived cell line LN-18 revealed more than 4000 methylated TSS. The gene-centric analysis indicated a complex pattern of DNA methylation exists along each autosome, with a trend of increasing density approaching the telomeres. Remarkably, 2% of CpG islands (CGI) were densely methylated, and 17% had significant levels of 5 mC, whether or not they corresponded to a TSS. Substantial independent verification, obtained from 95 loci, suggested that this approach is capable of large scale detection of cytosine methylation with an accuracy approaching 90%. In addition, we detected large genomic domains that are also susceptible to DNA methylation reinforced inactivation, such as the HOX cluster on chromosome 7 (CH7). Extrapolation from the data suggests that more than 2000 genomic loci may be susceptible to methylation and associated inactivation, and most have yet to be identified. Finally, we report six new targets of epigenetic inactivation (IRX3, WNT10A, WNT6, RARα, BMP7 and ZGPAT). These targets displayed cell line and tumor specific differential methylation when compared with normal brain samples, suggesting they may have utility as biomarkers. Uniquely, hypermethylation of the CGI within an IRX3 exon was correlated with over-expression of IRX3 in tumor tissues and cell lines relative to normal brain samples.

The micro-electrical-discharge-machining (μEDM) technique is an alternative to LiGA (Lithographie, Galvanoformung, Abformung) for fabricating metal-based high-aspect-ratio microscale structures (HARMS). Traditional μEDM is a serial subtractive machining technique in which cuts are performed sequentially, and is therefore difficult to use for generating complex micropatterns on surfaces. In this paper, we report results of a hybrid microfabrication approach, combining micropattern definition with LiGA fabricated Ni HARMS with parallel micropattern generation with μEDM. Multiple micropatterns with some geometrical complexity were successfully generated in parallel on elemental Ta and 304 stainless steel. The hybrid LiGA/parallel-μEDM strategy offers a credible alternative to conventional LiGA regarding fabrication of meso- and micro- scale mold inserts, and enables them to be fabricated out of high-temperature metals/alloys not achievable with electrodeposition.The micro-electrical-discharge-machining (μEDM) technique is an alternative to LiGA (Lithographie, Galvanoformung, Abformung) for fabricating metal-based high-aspect-ratio microscale structures (HARMS). Traditional μEDM is a serial subtractive machining technique in which cuts are performed sequentially, and is therefore difficult to use for generating complex micropatterns on surfaces. In this paper, we report results of a hybrid microfabrication approach, combining micropattern definition with LiGA fabricated Ni HARMS with parallel micropattern generation with μEDM. Multiple micropatterns with some geometrical complexity were successfully generated in parallel on elemental Ta and 304 stainless steel. The hybrid LiGA/parallel-μEDM strategy offers a credible alternative to conventional LiGA regarding fabrication of meso- and micro- scale mold inserts, and enables them to be fabricated out of high-temperature metals/alloys not achievable with electrodeposition.

Multivalent polymers, i.e., copolymers with multiple binding sites, have been proposed recently for stabilization of fusogentic liposomes and other liposomal colloids useful for drug delivery. The performance of such polymers critically depends on their molecular architecture, in particular the strength and frequency of surface anchoring sites along the backbone of a highly soluble polymer. In this work, we investigate the adsorption and surface forces due to multivalent polymers based on coarse-grained polymer models. We find that for W-type polymers that form dangling tails when all anchoring segments are attached to a surface, increasing the chain length at fixed polymer composition leads to a stronger repulsive barrier in the polymer-mediated surface forces thereby increasing the ability of the polymer to stabilize colloidal particles. This prediction conforms to an earlier experiment indicating that increasing the number of hydrophobic anchors along poly(ethylene glycol) polymers results in the cooperative behavior for both surface adsorption and steric stabilization. For M-type multivalent polymers that have weakly anchoring sites placed at the ends, however, addition of binding sites at fixed polymer composition could lead to negative cooperativity, i.e., the more binding sites, the less the amount of adsorption or the weaker the ability of surface protection. The theory also predicts that polymers with two anchoring sites (e.g., telechelic copolymers) are most efficient for colloidal stabilization.

The nonlinear modelling strategy and simulation of flexible components in micro-electro-mechanical structures are addressed in this paper. A newly developed Cosserat rod element approach is employed to model the dynamic equations of motion for MEMS components which are prone to nonlinear (moderately large amplitude) vibrations. Models constructed using this approach seek to capture the most significant characteristics of a microstructure in a few variables governed by a few ordinary differential equations of motion. For illustration, a resonator that comprises a resonator mass supported by four flexible beams is investigated using the proposed approach. A three-dimensional nonlinear dynamic model with six degrees of freedom is generated for the resonator. Finally, the nonlinear dynamical response of the resonator without external forces and torques has been presented through numerical simulations.

We report a new density functional theory (DFT) for block copolymers and its performance for representing the microscopic structure has been tested with the configurational-bias Monte Carlo simulation. The segmental density profiles are calculated for systems containing short block copolymers, represented by tangent-sphere square-well chains of sequences “AABB”, “AAAABBBB”, “ABBBBA”, “ABBBBBBA”, “BBAABB”, and “BBBBAABBBB” confined in slit pores where the planar surfaces attract “A” segments but repel “B” segments. The detailed segmental density profiles are calculated for block copolymers confined in slit pores where the planar surfaces attract “A” segments but repel “B” segments. For all conditions considered, the microscopic structures predicted by the DFT are in excellent agreement with the simulation results. Interesting loop and tail conformations of the block copolymers are observed near the selective surfaces. The effects of surface energy, chain length, and copolymer backbone structures on the microscopic segregation of “AB” segments are also investigated.

High temperature compression molding of Al plates with high-aspect-ratio microscale mold inserts was carried out. The bulk of the mold insert consists of electrodeposited Ni, fabricated with the LiGA (Lithographie, Galvanoformung, Abformung) technique. Both as-fabricated Ni inserts and Ni inserts conformally coated with a Ti-containing hydrocarbon (Ti-C:H) coating were used for Al micromolding at temperatures ∼450 °C. In-situ measurements of compression molding force, demolding force, and insert displacement were carried out. Insert conditions and microscale features generated on Al plates by molding were examined. Our results show that as-fabricated Ni inserts are not suitable for Al micromolding, and that Ni inserts conformally coated with a Ti-C:H coating allow repeated Al micromolding with 100% transfer of microscale features from the insert to the molded Al plate. Our results demonstrate, to our knowledge for the first time, successful replication of high-aspect-ratio Al microscale structures by high temperature compression micromolding.

Three new A-π-A-type compounds with trivalent boron, protected by two mesityl groups, as electron acceptor have been synthesized and investigated together with their two diphenylamino-ended D-π-D analogues. These boranes exhibit large two-photon absorption cross sections and high fluorescence quantum yields.

The diffusivities of methane in single-walled carbon nanotubes (SWNTs) are investigated at various temperatures and pressures using classical molecular dynamics (MD) simulations complemented with grand canonical Monte Carlo (GCMC) simulations. The carbon atoms at the nanotubes are structured according to the (m, m) armchair arrangement and the interactions between each methane molecule and all atoms of the confining surface are explicitly considered. It is found that the parallel self-diffusion coefficient of methane in an infinitely long, defect-free SWNT decreases dramatically as the temperature falls, especially at subcritical temperatures and high loading of gas molecules when the adsorbed gas forms a solidlike structure. With the increase in pressure, the diffusion coefficient first declines rapidly and then exhibits a nonmonotonic behavior due to the layering transitions of the adsorbed gas molecules as seen in the equilibrium density profiles. At a subcritical temperature, the diffusion of methane in a fully loaded SWNT follows a solidlike behavior, and the value of the diffusion coefficient varies drastically with the nanotube diameter. At a supercritical temperature, however, the diffusion coefficient at high pressure reaches a plateau, with the limiting value essentially independent of the nanotube size. For SWNTs with the radius larger than approximately 2 nm, capillary condensation occurs when the temperature is sufficiently low, following the layer-by-layer adsorption of gas molecules on the nanotube surface. For SWNTs with a diameter less than about 2 nm, no condensation is observed because the system becomes essentially one-dimensional.

Molding of Pb and Zn metal plates with LiGA (Lithographie, Galvanoformung, Abformung) fabricated Ni microscale mold inserts was carried out at 300 °C. Both as fabricated Ni inserts and Ni inserts conformally coated with Ti-containing hydrocarbon (Ti-C:H) coatings were used. The molding performance was characterized both in terms of feature generation on the metal plates and insert condition after molding. The present results demonstrate that, in cases where significant metal/insert chemical interactions exist, surface engineering of the mold insert is necessary to obtain satisfactory performance, and that conformal deposition of suitably engineered ceramic coatings onto Ni microscale mold inserts is an effective means for achieving high temperature micromolding of reactive metals.

A novel water-soluble paclitaxel complex has been prepared by inclusion complexation with bridged bis(β-cyclodextrin)s and characterized by means of ¹H NMR, SEM, powder X-ray diffraction patterns, TG-DTA, DSC, FT-IR, and 2D NOESY. The cyclodextrins were able to solubilize paclitaxel to levels as high as 2 mg/mL. Furthermore, the cytotoxicity of the novel complexes was assessed using a K562 leukemia cell line which indicated that drug concentrations of 10 pg/mL elicited an inhibitory effect.

Separation of gas mixtures by pressure swing and thermal swing adsorption processes is an established unit operation in the chemical industry. Mathematical simulations of these processes require precise knowledge of multicomponent gas adsorption equilibria, kinetics, and heats for the system of interest over all conditions of pressure, temperature, gas composition and adsorbate loading encountered by the adsorber during the separation process. Unfortunately, the published data on heats of adsorption are often not adequate. Limited heat data are generally available for pure gas adsorption, heat data for binary gas mixtures are rare, and heat data for mixtures containing three or more components are nonexistent.

This paper addresses the problem of the optimal design of batch plants with uncertain demands of products' quantities. A conceptual two-stage stochastic programming problem is formulated with an objective function containing investment costs and expected revenues from products. With the proposed formulation, the mode of operation of parallel units could be optimized so that, for different products, the operation of parallel units may take a different mode (i.e., in-phase or out-of-phase). The original formulation is transformed into different forms either for multiproduct and multipurpose batch plants. A hybrid algorithm for solving the problems is developed. Compared with previous work where the operating mode of parallel units was considered to be fixed during operation, more economic optimality is obtained.

The potential energy surface of C2H2FO is investigated at CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p) level. The results show that isomers of 1, 3, 4, 5, 5‘, 8, 9, and 9‘ are stable, and the energy barriers are more than 30 kcal/mol. Isomer 2 has, relatively speaking, much lower kinetic stability. The three cyclic isomers 6, 6‘, and 7 are less stable than the former, but more stable than the latter. The other isomers, such as isomers 1‘, 3‘, 4‘, 10, and 11 are less stable than isomer 2 in kinetics. Only isomer 1 was synthesized experimentally, and the calculated frequencies are in good agreement with experimental values, so we conjecture that in the future, other stable isomers may be synthesized by the experimental methods, for example, coming from such reactions as FCCH + OH, CH2F + CO, and so forth. Compared to the analogous C2H3O radical isomers, the energy order is changed. This may be due to conjugation of the carbonyl group in isomer 1 CH2CFO with the substituent fluorine at the α-position.

The reduction of HAuCl4 by Na2S has been reported to produce gold nanoparticles with an optical absorption in the near-infrared along with its characteristic absorption in the visible. The optical resonances in the visible are due to the gold surface plasma, which are a function of the geometry of the particles. The near-infrared absorption had been attributed to the formation of Au2S/Au core/shell structures. In this report we present new electronic absorption, electron microscopy, and X-ray absorption data in several systems to show that the near-infrared absorption does not involve core/shell structures. We further suggest that the near-infrared adsorption is most likely the result of the formation of aggregates of gold nanoparticles. The identification of the origin of the near-infrared resonance is critical in understanding the optical properties of metal nanoparticle systems.

In babies born after ICSI procedures, an increase of de-novo sex chromosome abnormalities has been observed. Several hypotheses have been proposed to explain these findings: an increased rate of sex chromosome aneuploidy in sperm of oligozoospermic men, or a preferential location of the sex chromosomes in the sub-acrosomal region of the sperm nucleus which leads to a reduced DNA decondensation of this region. In order to investigate which theory may be more reliable, we studied the localization of sex chromosomes and their aneuploidy rate in sperm in men undergoing ICSI.

BACKGROUND: In babies born after ICSI procedures, an increase of de-novo sex chromosome abnormalities has been observed. Several hypotheses have been proposed to explain these findings: an increased rate of sex chromosome aneuploidy in sperm of oligozoospermic men, or a preferential location of the sex chromosomes in the sub-acrosomal region of the sperm nucleus which leads to a reduced DNA decondensation of this region. In order to investigate which theory may be more reliable, we studied the localization of sex chromosomes and their aneuploidy rate in sperm in men undergoing ICSI. METHODS: Using fluorescent in-situ hybridization we studied sex chromosome localization and the aneuploidy rate for sex chromosomes and chromosome 18 in 20 oligospermic men undergoing ICSI and in 10 controls. RESULTS: In 40.94 and 52.92% of cases, the X and Y chromosomes respectively were localized in the sub-acrosomal region of the sperm nucleus compared with only 14.29% of cases of chromosome 18 (P < 0.001). An increase of sex chromosome aneuploidy in sperm of oligospermic men was observed; 2.91 versus 0.69% of controls (P < 0.001). CONCLUSIONS: Sex chromosomes are localized preferentially in the sub-acrosomal region of sperm and sex chromosome aneuploidy rate in the sperm of oligozoospermic men is higher than in controls.