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A non-equiatomic high entropy alloy (HEA) Ti40Nb25Zr25Ta5Mo5 (at.%) was designed by replacing 5% Ta with 5% Mo in a precursor Ti40Nb25Zr25Ta10 HEA for improved mechanical properties and reduced density. The Ti40Nb25Zr25Ta5Mo5 HEA fabricated by copper mould casting exhibited a nearly equiaxed grain structure (grain size: 96 ± 16 μm), but within each equiaxed grain, dendritic structures are discernible in the backscattered electron imaging mode. These dendrites are enriched in Ta, Nb and Mo, while the inter-dendritic regions contain higher Zr and Ti. The as-cast HEA achieved tensile yield strength (σ0.2) of 976 ± 8 MPa and strain to fracture (εf) of 16.80 ± 1.86%, well above the minimum requirements of σ0.2and εffor medical-grade titanium alloy Ti–6Al–4V (759 MPa and 10%). The formation of microscale and nanoscale shear bands and the presence of significant dislocations in the shear band boundary region played a key role in allowing this as-cast HEA to achieve the excellent combination of tensile strength and ductility. Furthermore, the HEA exhibited a lower wear rate, lower coefficient of friction and much higher corrosion resistance in Hank's solution (electrochemical assessments) than Ti–6Al–4V, making it a promising alternative biomedical alloy.

Introducing amorphous phases into the crystalline matrix is a new design strategy to improve the mechanical properties of Mg alloys. In this work, the effects of strain rate and amorphous nanopillar size on the interaction mechanism between the dislocation and precipitation in the Mg matrix were investigated by molecular dynamics simulation. The results show that the interaction mechanism between dislocation and amorphous precipitation depends on strain rate and amorphous nanopillar size. At strain rates of 5 × 107/s and 5 × 108/s, the amorphous precipitation strengthens the Mg matrix due to the pinning effect of the amorphous precipitation relative to the dislocation. The interaction mechanism changes from merging and canceling of dislocation to the cross-slip mechanism with the increase of precipitation size. Moreover, the strengthening effect of the large-sized amorphous phase on the dislocation is noticeable. However, the amorphous precipitation softens the Mg matrix at strain rates of 5 × 109/s and 1 × 1010/s. The underlying mechanism varies from the dislocation shearing mechanism to the generation of dislocation loops with the increase of the amorphous precipitation size. This research can provide theoretical guidance for developing and designing new high-performance Mg alloys.

ABSTRACTBackgroundThe variation of serum lipid levels can be part-related to certain genes. One such gene, SLCO1B1, encodes a transporter that may have a role in lipid metabolism. We hypothesised that differences in certain SLCO1B1genotypes are related to levels of serum lipids.Materials and methodsWe recruited 636 subjects who were genotyped for SLCO1B1variants *1a, *1b, *5 and *15. Routine liver function tests, renal function tests and routine lipid indices were measured by standard techniques.ResultsThe most frequent genotypes were *1b/*1b (29.3%), *1b/*15 (27.5%), *1a/*1b (21.1%), *1a/*15 and *1b/*5 (10.2%) and *1a/*1a (8.5%). There were significant differences in levels of triglycerides and HDL in the four SLCO1B1genotypes *1a/*1a, *1b/*1b, *1a/*1b and *1b/*15 (all p < 0.05).ConclusionThe genotypes *1a/*1a and *1a/*1b indicate a high risk of cardiovascular disease, while the *1b/*1b group may have a relatively low risk. SLCO1B1may be involved in the metabolism of triglycerides and HDL. We have provided a tool for identifying potentially high-risk groups that could be helpful for early diagnosis and prevention, individualized drug therapy and even gene therapy.

Patients with DLC (diamond like carbon)-coated artificial joints may be exposed to a wide size range of DLC wear debris (DW). In this study, the cytotoxicity of DW of different size ranges (0–0.22, 0.22–0.65, 0.65–1.0, and 1.0–5.0 μm) was evaluated. The microstructure and physical characteristics of DW were investigated by Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscope (SEM), and dynamic light scattering (DLS). Macrophages, osteoblasts, and fibroblasts were incubated with DW of different size ranges respectively followed by cytotoxicity evaluations of inflammatory cytokines, alkaline phosphatase (ALP) assays, and related signal protein expression analysis. The results showed that, except for the size range of 0–0.22 μm, DW cytotoxicity showed a size-dependent (0.22–5.0 μm) decrease with increasing size. Within the range of 0.22–5.0 μm, DW of larger size resulted in lessened inflammatory response and enhanced osteoblastogenesis and fibrogenesis, with increased viability of cells (macrophages, osteoblasts, and fibroblasts), better morphology, less release of pro-inflammatory factors and more release of anti-inflammatory factors. The results demonstrated that DW sizes below 0.22 μm had less negative effects on cell adhesion and growth because of the BSA (bovine serum albumin) encapsulation effect. These findings provide valuable knowledge about the comprehensive mechanism of promotion of inflammatory response and inhibition of osteoblastogenesis and fibrogenesis induced by DW. In conclusion, an effective system of biocompatibility evaluation for different sizes of DW was derived.

CSN6, a critical subunit of the constitutive photomorphogenesis 9 (COP9) signalosome (CSN), has received attention as a regulator of the degradation of cancer-related proteins such as p53, c-myc and c-Jun, through the ubiquitin-proteasome system, suggesting its importance in cancerogenesis. However, the biological functions and molecular mechanisms of CSN6 in glioblastoma (GBM) remain poorly understood. Here, we report that GBM tumors overexpressed CSN6 compared with normal brain tissues and that CSN6 promoted GBM cell proliferation, migration, invasion and tumorigenesis. Erlotinib, a small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, was used to reveal that the proliferative and metastatic effects of CSN6 on GBM cells were EGFR dependent. We also found that CSN6 positively regulated EGFR stability via reduced levels of EGFR ubiquitination, thereby elevating steady expression of EGFR. In addition, this study is the first description of a novel role for the CSN6-interacting E3 ligase, CHIP (carboxyl terminus of heat-shock protein 70-interacting protein), regulating EGFR ubiquitination in cancer cells. We showed that CSN6 associated with CHIP and led to CHIP destabilization by increasing CHIP self-ubiquitination. Moreover, CSN6 decreased CHIP expression and increased EGFR expression in the tumor samples. Deregulation of this axis promoted GBM cell’s proliferation and metastasis. Thus, our study provides insights into the applicability of using the CSN6-CHIP-EGFR axis as a potential therapeutic target in cancer.

The objective of this investigation was to evaluate whether intravaginal infusion of probiotics (a lactic acid bacteria cocktail) around parturition would influence metabolic status and increase milk production of transition dairy cows. One hundred pregnant Holstein dairy cows were assigned to 1 of the 3 experimental groups receiving intravaginal infusion of probiotics or carrier (i.e., sterile skim milk) once a week at wk –2, –1, and +1 relative to calving as follows: 2 consecutive probiotics before parturition and 1 carrier dose after parturition (TRT1), 3 consecutive probiotics doses around parturition (TRT2), and 3 consecutive carrier doses around parturition (CTR). The probiotics were a lyophilized culture mixture composed of Lactobacillus sakeiFUA3089 and Pediococcus acidilacticiFUA3138 and FUA3140 with a cell count of 108to 109cfu/dose. Blood was sampled from wk –2 to +3 and milk was sampled on the third day in milk (DIM) and from wk +1 to +5 on a weekly basis. Feed intake and milk production was monitored until wk +8. Results showed that the TRT2 group (366.12 ± 49.77 μmol/L) had a lower (P= 0.01) concentration of NEFA in the serum than the CTR group (550.85 ± 47.16 μmol/L). The concentrations of IgG in the milk were 32.71 ± 3.00 mg/mL in the TRT1 group, 17.47 ± 4.54 mg/mL in the TRT2 group, and 6.73 ± 3.43 mg/mL in the CTR group at 3 DIM (P< 0.01). Meanwhile, both the TRT1 and the TRT2 group had lower haptoglobin in the milk compared with the CTR group at 3 DIM (P< 0.01). The TRT1 group had greater milk protein content than the CTR group (2.99 ± 0.04 vs. 2.82 ± 0.04%; P= 0.02), whereas the TRT2 group tended to have greater lactose content compared with the CTR group (4.53 ± 0.03 vs. 4.44 ± 0.03%; P= 0.05). The effect of treatment interacted with parity with regards to milk production and feed efficiency. Multiparous cows in the TRT1 and TRT2 groups had greater milk production and feed efficiency than those in the CTR group (P< 0.01 and P= 0.02, respectively). Among primiparous cows, those in the TRT2 group had greater milk production (P= 0.04) whereas those in the TRT1 group had lower feed intake (P< 0.01) than those in the CTR group. Both the TRT1 and the TRT2 groups had enhanced feed efficiency compared with the CTR group (P< 0.01). In conclusion, intravaginal infusion of lactic acid bacteria modulated concentrations of selected serum metabolites and milk components and increased milk efficiency of transition dairy cows.

Currently, trastuzumab resistance is a major clinical problem in the treatment of Her2-overexpressing breast cancer. The underlying molecular mechanisms are not fully understood. Our previous study demonstrates that ß2-adrenergic receptor (ß2-AR) and Her2 comprise a positive feedback loop in human breast cancer cells and that crosstalk between Her2 and ß2-AR affects the bio-behaviors of breast cancer cells, suggesting that the ß2-AR activation may be involved in trastuzumab resistance. In this study, we show that the expression of ß2-AR, which mediates most catecholamine-induced effects, negatively correlates with trastuzumab response in the patients with Her2-overexpressing breast cancer. Catecholamines potently antagonize the anti-proliferative effects of trastuzumab both in vitroand in vivo. Catecholamine stimulation upregulates the expression of miR-21 and MUC-1 by activating Her2 and STAT3, leading to deficiency of phosphatase and tensin homolog and activation of phosphatidylinositol-3-kinase (PI3K) and Akt. Through inhibition of miR-199a/b-3p, catecholamines induce the mammalian target of rapamycin (mTOR) activation. Thus, trastuzumab resistance-dependent PI3K/Akt/mTOR pathway is controlled by catecholamine-induced ß2-AR activation. The data indicate that ß2-AR is a reliable molecular marker for prediction of response probability to trastuzumab-based therapy in breast cancer. We also demonstrate that ß-blocker propranolol not only enhances the antitumor activities of trastuzumab but also re-sensitizes the resistant cells to trastuzumab. Our retrospective study shows that concurrent treatment of ß-blocker and trastuzumab significantly improved progression-free survival and overall survival in the patients with Her2-overexpressing metastatic breast cancer, implicating the possibility for combination therapy with trastuzumab plus ß-blocker in Her2-overexpressing breast cancer.

In this contribution, a combination of two methods for the evaluation of the best behavior including situated decisions based on the assessment of human actions or decisions related to actions is presented. The suggestion of the behavior is based on a Situation-OperatorModeling approach in combination with a stochastic state machine. While the Situation- Operator-Modeling (SOM) allows the concrete, individualized, and situated modeling of human interaction in formal context, an approach is used to work with a stochastic state automata. First based on observations (training), the observed transition probability between predefined states. The combination of both practical and theoretical approaches allows the combined prediction of human behavior.

Positron lifetime spectra of polymers have been resolved into continuous lifetime distributions with the aid of the Laplace inversion algorithm implemented in the CONTIN program. The free-volume hole size distributions are calculated from the o-Ps lifetime distributions based on the semi-empirical quantum mechanical model of a spherical hole. Due to various factors such as the statistics, instrument drift, and choice of the reference spectrum, the obtained lifetime distributions are only close to the real ones. Experiences in using the CONTIN program and experimental techniques in approaching the true free-volume distributions are discussed. A variety of free-volume distributions as a function of temperature, pressure, and aging time in several poiymers is reported, which are in good agreement with the current free-volume theories on polymers. This paper summarizes the results obtained at the University of Missouri-Kansas City (UMKC) during the past three years (1991-93).

Aquaporin 8 (AQP8) may be involved in cytoplasmic condensation and fluid formation in the vas deferens during the process of spermiogenesis. In the present study, using reverse transcription polymerase chain reaction (RT-PCR) combined with DNA sequencing technology, the splice isoforms of AQP8 post-transcriptionally formed by alternative splicing in porcine testis at various developmental stages were analysed, and the differences in the amino acid sequences encoded by the splice isoforms were compared. The results showed that a total of three splice isoforms of AQP8 mRNA, including full-length mRNA, were produced via alternative splicing in porcine testes at the four developmental stages. Because the number of bases removed during splicing was not an integer multiple of 3, the amino acid sequence and protein structure of AQP8 were significantly altered after alternative splicing.

Ta was added to laser clad NiCrBSi coating to improve wear resistance. In situsynthesised TaC particles of nearly equiaxed shape were uniformly dispersed in the coating. The colony that contained acicular Cr rich boride or carbide grew radially around the TaC particle and had a strong bond with the particle. The TaC particles had good bonds with the matrix, and tended to be crushed and impressed into the matrix instead of being pulled out from the wear surface during the wear process. The NiCrBSi+Ta coating exhibited higher fracture toughness, and higher abrasive and adhesive wear resistance than the NiCrBSi coating. The primary wear mechanism of the NiCrBSi+Ta coating was abrasion combined with the oxidation process under all test conditions while the main wear mechanism of the NiCrBSi coating was abrasion and microflaking under a low load (30 N), and adhesion and oxidation under a high load (75 N).

. Deployable truss has a wide range application in aerospace industry. Two important issues in the design of all deployable space structures are the weight and its stiffness in the deployed state. This is because lower weight of deployable truss can greatly save the cost of launching and higher stiffness can improve the loading capacity. This paper aims to design a tapered deployable mast with lower weight and higher stiffness. The mobility analysis and geometry condition is first introduced. Then structural optimization problem with mass as its objective is solved by using ANSYS Parametric Design Language (APDL). The optimal results show the proposed tapered mast has excellent performance on mechanical properties by comparing with normal mast with identical cross section. Finally, some possible applications and problems are described.

This prospective, three-centre study tested for antimicrobial susceptibility in 898 isolates of Haemophilus influenzaebetween 2000 and 2002 in Chinese children aged under 5 years with acute upper respiratory tract infection. The average incidence of β-lactamase production was 12.0%. Overall, 88.0% of isolates were susceptible to ampicillin, 100.0% were susceptible to amoxicillin/clavulanic acid, ceftriaxone, cefuroxime and azithromycin, and 99.0% were susceptible to ciprofloxacin. Isolates from Beijing and Shanghai had a lower susceptibility to tetracycline (57.0% and 61.0%, respectively) compared with those from Guangzhou (81.0%), while trimethoprim/sulfamethoxazole susceptibilities in Shanghai (47.0%) and Guangzhou (54.0%) were significantly higher than in Beijing (35.0%). A total of 34.5% of all the isolates were susceptible to all eight of these antimicrobial agents and 12.8% were multi-drug resistant. Ampicillin resistance increased over the duration of the study. These findings show that β-lactamase production and ampicillin resistance among isolates from Chinese children with upper respiratory tract infection are increasing, and highlight the strong correlation between ampicillin resistance and resistance to cefaclor, chloramphenicol and tetracycline in H. influenzaeisolates.

This prospective, multicentre, nasal carriage study in Chinese children with upper respiratory infection was carried out over the period from 2000 to 2002. Overall, the prevalence of pneumococcal carriage was 24.9%. Antimicrobial susceptibility tests were performed for 887 isolates of Streptococcus pneumoniaeof which 33.5% were intermediately susceptible to penicillin and 6.4% were resistant. Multidrug resistance was very common. Pneumococcal strains (n= 625) were serotyped, showing 72.2% were covered by the 23-valent pneumococcal polysaccharide vaccine and 57.6% by the seven-valent pneumococcal conjugate vaccine. Sero-groups 19 and 23 were significantly associated with penicillin resistance, which is increasing in China. Erythromycin, tetracycline and sulphamethoxazole/trimethoprim cannot be recommended as first-line treatments for respiratory tract infection as in some other developing countries. These features of serotype distribution are of importance for surveillance in the era of the new conjugate vaccine. In particular, these features will allow for documentation of serotype replacement after the introduction of widespread vaccination.

The elastic modulus in the region of a grain boundary for a commercial 2.6Ni-Cr-Mo-V steel has been obtained from Misra’s observation of grain-boundary segregation of sulphur under a tensile stress. The result is in agreement with the theoretical estimation.

This paper considers a heterogeneous M/G/2 queue. The service times at server 1 are exponentially distributed, and at server 2 they have a general distribution B(·). We present an exact analysis of the queue length and waiting time distribution in case B(·) has a rational Laplace–Stieltjes transform. When B(·) is regularly varying at infinity of index −ν, we determine the tail behaviour of the waiting time distribution. This tail is shown to be semi-exponential if the arrival rate is lower than the service rate of the exponential server, and regularly varying at infinity of index 1−ν if the arrival rate is higher than that service rate.

This paper presents a simulation and visualization system for plasma spraying of functionally graded materials (FGM). The recently modified CFD code, LAVA-P, that incorporates a well-verified model for plasma gas flow and chemistry is employed. The particle movement and its trajectory are described within a Lagrangian formulation by considering drag as the major driving force, and the particle melting, evaporation, and resolidification are considered using a recently developed model for particle-flame interaction. In addition to the noncontinuum and variable property effects associated with high-temperature plasma, the effects of particle evaporation on particle momentum and heat transfer are also taken into account. Calculations are performed for NiCrAlY and ZrO2powders for a wide range of size distributions. The influences of power levels and flow rate of H2on plasma flow field and, hence, on the particle velocity and temperature are investigated. The predicted velocity and temperature fields agree well with the measurements under similar spraying conditions. With the help of a special in-house built process animation and visualization algorithm, the powder injection conditions, such as the number of injectors, injector location, and injection velocity, are investigated and can be optimized to obtain coatings with a specified distribution of different species.

Immediately downstream from the previously isolated Treponema denticola ATCC 35405 prtB gene coding for a chymotrypsinlike protease activity, an open reading frame, ORF3, was identified which shared significant homology with the highly conserved domains (HCDs) of bacterial methyl-accepting chemotaxis proteins (MCPs). Nucleotide sequencing of this ORF revealed that the gene would code for a protein with a size of approximately 41 kDa. In addition, this sequence contained a domain which was virtually identical to the HCD of a recently characterized MCP, DmcA, of strain 35405. Therefore, this ORF was named dmcB. Northern blot analysis suggested that dmcB was part of an operon structure containing prtB. Insertional inactivation of dmcB utilizing an ermF-ermAM cassette resulted in a mutant with decreased chemoattraction toward nutrient supplements. In addition, the mutant displayed an altered pattern of methylated proteins under conditions of chemotaxis. Inactivation of the dmcB gene also attenuated the methylation of the DmcA protein. These results suggest that the dmcB gene codes for an MCP in T. denticola which may interact with other MCPs in these organisms.

Treated silica xerogels with controlled porosity and surface area were prepared by the in situ treatment of hydrogels with hexamethyldisiloxane or alkylchlorosilanes in the presence of isopropyl alcohol. The resulting hydrogels were hydrophobic and readily transferred to nonpolar organic solvents upon contact. The surface area and porosity of the xerogel were controlled by varying the pH, time, and temperature used to polymerize the hydrogel prior to treatment. In general, the surface area decreased with increases in aging time or temperature, whereas the total pore volume and pore size increased. Silylation of the hydrogel in the aqueous phase retains the structure of the hydrogel and permits isolation with minimum structure collapse. By using this technique, silylated xerogels with surface areas ranging from 200 to >700 m²/g and pore volumes of 1.5 to 3.8 cm³/g were obtained.

TaqDNA polymerases in which the phenylalanine is substituted by a tyrosine at position 667 (Taq F667Y) are members of a new class of DNA polymerases that incorporate chain-terminating dideoxyribonucleoside triphosphates (ddNTPs) much more efficiently than the wild-type TaqDNA polymerase. Improved incorporation of ddNTPs into DNA during cycle sequencing using AmpliTaq®DNA polymerase, FS (Taq-FS, a member of the Taq F667Y family), and dyelabeled primers results in nearly uniform peak heights in the sequencing trace. This is not the case when dye-labeled ddNTPs are used in Taq-FS cycle sequencing reactions. While the rate of dye-terminator incorporation is more efficient with Taq-FS, the peak pattern is still highly variable and different from that produced by the wild-type enzyme. We have systematically examined pairs of sequence-tagged sites that vary at only a single nucleotide to determine how base changes influence the peak heights of neighboring bases in sequencing traces generated by the Taq-FS dye-terminator chemistry. In 31 of 64 possible 3-base windows (48), we find that the peak height of a particular base can be predicted by knowing just one or two bases 5′ to the base in question. We have also compared and contrasted the peak patterns produced by the Taq-FS enzyme with those previously identified for the wild-type enzyme. Establishing the patterns in peak heights within local sequence contexts can improve the accuracy of base-calling and the identification of polymorphisms/mutations when using the Taq-FS dye-terminator cycle-sequencing chemistry.

Mechanical function and coronary hemodynamics were assessed in 73 isolated rabbit hearts randomly subjected to 0, 10, 20, 30, or 45 minutes of 37 degrees C global ischemia and 45 minutes of reperfusion in either a modified Krebs buffer or homologous blood-perfused Langendorff mode ( n = 7 to 9 hearts per group). Isovolumic developed pressure, resting coronary flow, and response to endothelium-dependent (bradykinin) and -independent (nitroglycerin) agonists were quantitated at defined preload and heart rate. Perfusate did not influence systolic performance, which was impaired after 30 minutes of ischemia and fell to 64% to 72% of preischemic values after 45 minutes of ischemia ( p < 0.05). However, basal coronary flow was at least sixfold greater in crystalloid-perfused hearts. Moreover, coronary hyperemia ( p < 0.05) persisted for Krebs-perfused hearts subjected to all but the longest ischemic interval. After equilibration, all postischemic blood-perfused hearts had basal flow unchanged from before ischemia. Bradykinin and nitroglycerin induced similar increases in coronary flow for each group before and after each ischemia interval. However, the magnitude of this increase was greater in blood-perfused hearts ( p < 0.01) and was not attenuated by the ischemic times encompassed in this protocol. In contrast, endothelium-dependent and -independent coronary flow reserve was abolished after 20 minutes of ischemia or longer in Krebs-perfused hearts. These data suggest that the unphysiologic resting flow patterns of crystalloid-perfused isolated hearts obfuscate interpretation of the interaction between coronary flow reserve and ischemic injury. (J THORAC CARDIOVASC SURG 1995; 109: 466-72)

Abstract:  The effects of oscillating leading-edge flaps on leading-edge vortices and vortex breakdown were investigated for a delta wing with upward-deflected flaps. The variation of breakdown location revealed hysteresis loops. The time-averaged breakdown location over one cycle may move upstream or downstream compared to the quasi-steady case, depending on the amplitude of flap oscillations and angle of attack. Measurements of the phase-averaged velocity upstream of breakdown did not reveal any correlation to the response of breakdown location. The effect of oscillating flaps is largest when the breakdown location is near the trailing-edge region in the static case.

Perfluorosulfonic Acid (PFSA)]/[Organically-Modified Silicon Oxide (ORMOSIL)] hybrids were formulated via sol-gel reactions of mixtures of tetraethoxysilane (TEOS) and diethoxydimethylsilane (DEDMS) in the nanophase-separated morphology of a PFSA membrane (Nafion®). The molecular structures of the ORMOSIL phases were investigated by 29Si solid state NMR spectroscopy and the spectra compared with those of corresponding bulk ORMOSILs. PFSA-in situ ORMOSIL composition can be tailored by manipulating TEOS/DEDMS source solution composition and quantified by 29Si solid state NMR spectroscopy. Copolymerization of TEOS and DEDMS monomers, rather than block formation, occurs within the PFSA as well as in the bulk. As DEDMS feed concentration increases, ORMOSIL nanostructures are more hydrophobic and more flexible. Dimethylsiloxane rings are dominant in PFSAs in which hydrolysis + condensation of pure DEDMS occurs.

Nafion®/SiO2, Nafion®/[ORganically MOdified SILicate (ORMOSIL)] and Nafion®/dimethylsiloxane hybrids were created via in situ sol–gel reactions for tetraethoxysilane, diethoxydimethylsilane, and their mixtures. Differential scanning calorimetry studies showed a broad endotherm for unfilled Nafion®-H⁺ at Tα ≈ 215°C that shifts upward for the Q : D = 1 : 0 (mol : mol) [Q = Si(O1/2)4, D = (O1/2)2Si(CH3)2] hybrid, then shifts downward with decreasing Q : D. This endotherm likely arises from release of H2O molecules bound to ≡Si—OH groups and condensation reactions among silanol groups. The decrease in Tα is rationalized in terms of an increasing fraction of flexible D units that disrupt hydrophilic Q structures. Tm shifts to lower temperatures with decreasing Q : D, and it is suggested that main chains are restricted by side chains embedded in silicon oxide nanoparticles, but D unit insertion causes side chains to be anchored less strongly. Thermal gravimetric analysis indicates that the first mass loss step for Nafion®-H⁺ shifts to higher temperatures as D : Q increases; an increase in D unit fraction inhibits Q unit degradation by evolved HF. A dynamic mechanical transition at Tα may arise from side chain motions, and the increase in Tα in passing from unfilled Nafio®-H⁺ to the 1 : 0 hybrid is due to side chain immobilization by their entrapment in silicon oxide domains. The progression 0 : 1 → 1 : 2 → 1 : 1 → 2 : 1 generates increasing mechanical tensile strength and decreasing ductility; strength enhancement might be due to entanglements between ORMOSIL and pure silicon oxide phases and side chains. Liquid sorption experiments quantified the affinity of these hybrids for solvents of varying polarity. A dielectric relaxation for the 0 : 1 hybrid at about 1.5 kHz might be related to side chain mobility. A weaker relaxation in the range 10⁴–10⁵ Hz exists for the 0 : 1 and 1 : 1 hybrids and Nafion®-H⁺, but not for the 1 : 0 hybrid that exhibits the behavior ɛ' ~ f⁻ⁿ over a broad frequency (f) range, suggestive of intercluster proton hopping. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:747–763, 1998

Pyrene (Py) photophysical probes were used to interrogate structural diversity within [1] Nafion/[silicon oxide] and [2] Nafion/[ORMOSIL] hybrids. The interior of the silicon oxide phase in [1] has the most polar environment wherein Py is trapped in silicon oxide cages in the vicinity of −SO3^- groups. Polar/nonpolar interphase regions in [1] are next in order of decreasing polarity. The interior of the ORMOSIL phase in [2] displays lowest polarity, reflecting CH3 groups in Py-encapsulating ORMOSIL cages, and the interphase ranks somewhat higher in polarity. Water uptake is ordered:  Nafion/ORMOSIL &lt; unfilled Nafion-H⁺ &lt; Nafion/[silicon oxide]. The hydrophilicity of unfilled Nafion-H⁺ is adjustable by tailoring the organic content of the incorporated sol−gel-derived nanophase as polarity determined from fluorescence emission and water uptake correlate well. Fluorescence emission of Py monitored nanostructural polarity shifts that result from secondary in situ gel growth induced by annealing. Additional condensation of SiOH groups and liberation of volatiles is promoted by increasing temperature/time, as evidenced by diminishing polarity. Polarity decrease with annealing is more profound for Nafion/[ORMOSIL incorporating Py] than for Nafion/[silicon oxide incorporating Py] as polar solvents are removed more easily from the less polar ORMOSIL nanophase.

Mesoporous organosilica as drug delivery carriers capable of achieving improved cargo release, enhanced biodegradation, and direct imaging with prolonged circulation time and tracking cargo distribution is highly in demand for biomedical applications. Herein, we report a ditelluride-bridged mesoporous organosilica nanoparticle (DTeMSN)/polyethylene glycol-curcumin (PEG-CCM) nanocomposite through coassembly with oxidative/redox and self-fluorescent response. Tellurium is introduced into the silica framework for the first time as a drug delivery vehicle. In this case, the DTeMSNs as an inner core enable disassembly under oxidative and redox conditions via the cleavage of ditelluride bond, facilitating the drug release of doxorubicin (DOX) in a matrix degradation controlled manner. Through the systematical comparison of diselenide-bridged MSNs and DTeMSNs, DTeMSNs exhibit remarkable advantages in loading capacity, drug release, and degradation behavior, thereby significantly affecting the cytotoxicity and antitumor efficacy. The self-fluorescent response of PEG-CCM shell coated on the surface of DTeMSNs can real-timely track the cellular uptake, DOX release, and biodistribution owing to the intrinsic and stable fluorescence of CCM. Moreover, PEG-CCM could prolong circulation time, provide preferable drug accumulation in tumors, and increase antitumor efficacy of DOX-loaded DTeMSNs. Our findings are likely to enrich the family of organosilica that served as fluorescence-guided drug delivery carriers.

Hydrogen storage and CO2capture are of great importance for efficient fuel usage and environmentally clean methods. Here, we report a series of 7,7,8,8-tetracyanoquinodimethane-derived covalent triazine frameworks (TCNQ-CTFs) with different specific surface areas for hydrogen and CO2storage. Such TCNQ-CTFs exhibit maximum H2and CO2adsorption capacities up to 2.79 wt% (77 K, 1 bar) and 5.99 mmol/g (273 K, 1 bar), respectively, which are the highest values among reported covalent triazine frameworks.Theory simulation by using the Grand Canonical Monte Carlo (GCMC) method revealed that abundant nitrogen and defects induced by annealing treatment are the reasons for the high adsorption capacity of the material. This work not only contributes a superior material for both hydrogen and CO2storage under ambient conditions but also deepens the knowledge on its adsorption mechanism, thus guiding people to engineer more efficient storage materials.

Three new guaianolides, 10α-hydroxy-3-oxoguaia-4(15),11(13)-dieno-12,6α-lactone (1), 10α-hydroxy-3-oxo-4βH-guaia-11(13)-eno-12,6α-lactone (2), and 10α-hydroxy-3-oxoguaia-4,11(13)-dieno-12,6α-lactone (3), named chinensiolides A, B, and C were isolated from the whole plant of Siyekucai (Ixeris chinensis). The structures were determined by HREIMS, UV, IR, and one- and two-dimensional NMR techniques (¹H and ¹³C NMR, COSY, HMQC, HMBC, and NOE difference and NOESY experiments). Compounds 1 and 2 were indicated to be a mixture of flexible conformers by analyses of their 1D NOE and NOESY spectra as well as the temperature dependence of their ¹H and ¹³C NMR spectra. Chinensiolide B (2) was transformed to chinensiolide C (3) in a three-step conversion.

Near- and far-field radiation patterns are analyzed for whispering-gallery-mode lasing in native-oxide-confined vertical-cavity surface-emitting lasers. Calculations from classical antenna theory based on the higher-order Bessel functions are compared with experiment and shown to be a useful predictor of the measured radiation fields. The most interesting features of the lasing modes are the multiple and uniformly distributed intensity spots in the near and far fields.