Tuning the resonant frequency of resonators using molecular surface self-assembly approach.

In this work, a new method to tune the resonant frequency of microfabricated resonator using molecular layer-by-layer (LbL) self-assembly approach is demonstrated. By simply controlling the polymer concentration and the number of layers deposited, precisely tuning the frequency of microfabricated resonators is realized. Due to its selective deposition through specific molecular recognitions, such technique avoids the high-cost and complex steps of conventional semiconductor fabrications and is able to tune individual diced device. Briefly, film bulk acoustic resonator (FBAR) is used to demonstrate the tuning process and two types of LbL deposition methods are compared. The film thickness and morphology have been characterized by UV-vis reflection spectra, ellipsometer and AFM. As a result, the maximum resonant frequency shift of FBAR reaches more than 20 MHz, meaning 1.4% tunability at least. The minimum frequency shift is nearly 10 kHZ per bilayer, indicating 7 ppm tuning resolution. Pressure cooker test (PCT) is performed to evaluate the reliability of LbL coated FBAR. Furthermore, applications for wireless broadband communication and chemical sensors of LbL coated FBAR have been demonstrated.

Characterization of poly(4-vinylpyridine 1-oxide) by free-solution capillary electrophoresis and micellar electrokinetic chromatography.

The migration characteristics of poly(4-vinylpyridine 1-oxide) (PVP-NO) in phosphate buffers of acidic pH (20 mM H3PO4 or NaH2PO4) have been studied using both free-solution capillary electrophoresis (FSCE) and MEKC. To inhibit adsorption, 250 mM o-phosphoethanolamine (2-aminoethyl dihydrogen phosphate) was used. In FSCE, PVP-NO showed a narrow peak and a broader band, both having anionic behavior. These peak and band were attributed to the free and aggregated or micellized PVP-NO forms, respectively. According to surface tension measurements, the CMC of SDS in the BGE was 1.8 and 0.48 mM in the absence and in the presence of 1000 microg/mL PVP-NO, respectively, and the association of the polymer with SDS was completed at 9.7 mM SDS. Using MEKC, a narrow peak and a broader band also appeared at SDS concentrations of ca. 1 mM, and their intensity increased with the SDS concentration. These peak and band were attributed to the formation of mixed micelles constituted by both free PVP-NO/SDS and aggregated PVP-NO/SDS, respectively. The determination of PVP-NO by FSCE in commercial additives for laundry was demonstrated.

[Trials of casual treatment of silicosis]. / Próby leczenia przyczynowego pylicy krzemowej.

Silica-induced lung injury and the development of silicosis is one of the major occupational diseases. Accumulation and deposition of respirable dust containing silica mineral particles in the lung produces chronic lung disease characterized by granulomatous and fibrotic lesions. Knowledge of precise mechanisms, which induce this process is still limited, hence problems faced in the treatment of silicosis, especially the casual one. This article describes various trials of casual silicosis treatment with tetrandrine (Tet), isolated from the root of Stephania tetrandra, tumor necrosis factor (TNF) antagonists, polyvinyl-pyridine-N-oxide (PVNO), aluminum compounds, corticosteroids or bronchoalveolar lavage (BAL). The existing methods are not sufficient, which warrants further investigations. At present, prevention of the disease and treatment of its complications are most important.

Mode of action of poly(vinylpyridine-N-oxide) in preventing silicosis: effective scavenging of carbonate anion radical.

Small particles of crystalline silicon dioxide (crystallites) are exceptionally toxic. Inhalation of quartz crystallites causes silicosis, a devastating lung disease afflicting miners, particularly coal and stone workers. Poly(vinylpyridine-N-oxide)s (PVPNOs) have been applied in the prevention and treatment of silicosis, but their mode of action has been obscure. Recently, the sites of inducible *NO synthase activation and of nitrotyrosine formation were associated anatomically with the pathological quartz particle-caused lesions in the lungs. It has been suggested that the *NO formed combines rapidly with O2*- to yield ONOO-, a potential mediator of lung injury following silica exposure. Here, we show that PVPNOs do not react with peroxynitrite but scavenge exceptionally rapidly CO3*- radicals, which are produced in the decomposition of ONOO- in bicarbonate solutions. The rate constant for the reaction of CO3*- with PVPNO was found to be independent of the type and size of PVPNO, i.e., k = (1.9 +/- 0.2) x 10(5) M(-1) s(-1) per monomer. In contrast, the rate constant for the reaction of CO3*- with the small molecule 4-methylpyridine N-oxide did not exceed 1 x 10(4) M(-1) s(-1). The underlying reason for the difference is that, in the dissolved polymeric PVPNOs, the electrostatic repulsion between the N-oxide zwitterions destabilizes them, increasing dramatically their pKa. The protonated N-oxides at physiological pH have abstractable hydrogen atoms and are expected to react rapidly with CO3*-, just as cyclic hydroxylamines do. It is also shown that PVPNO inhibits tyrosine nitration by peroxynitrite at pH 7.6 in the presence of excess of CO2 in a concentration-dependent manner. Hence, binding of PVPNO to the quartz particles and eliminating CO3*- could prevent the killing of macrophages, the associated release of macrophage-recruiting cytokines, and the amplification of the local concentration of *NO by the recruited macrophages. The latter causes necrosis of the macrophage-infiltrated lung tissue and, upon repair of the necrotic lesion, results in the growth of the dysfunctional fibrotic tissue, which is the hallmark of silicosis.

Pulmonary inflammation in rats after intratracheal instillation of quartz, amorphous SiO2, carbon black, and coal dust and the influence of poly-2-vinylpyridine-N-oxide (PVNO).

Effects of poly-2-vinylpyridine-N-oxide (PVNO) were investigated in numerous in vivo and in vitro studies published in the nineteen sixties and seventies. These studies showed that PVNO inhibited development of fibrosis from quartz dust and improved lung clearance of quartz after inhalation exposure. Ameliorating effects of PVNO were observed also for pulmonary damage from colloidal SiO2 and organic substances, and the fibrogenic inflammation caused by carrageenan. Although it is not proven that silicosis is a precondition for quartz-induced lung tumours, we investigated the hypothesis that PVNO could reduce the lung tumour risk from quartz in rats. A carcinogenicity study was therefore started in rats with the main focus on the quantitative relationships among pulmonary inflammation, fibrosis and neoplasia caused by intratracheal instillation of 3 mg quartz DQ 12 with or without additional subcutaneous PVNO treatment. Other study groups were treated with multiple dust instillations, i.e. 30 instillations of 0.5 mg amorphous SiO2 at intervals of 2 weeks, 10 instillations of 0.5 mg of ultrafine carbon black or 1 mg coal at weekly intervals. The analyses of the bronchoalveolar lavage fluid (BALF) 9 months after start of the life-time study showed that the aim of producing similar levels of increased enzyme concentrations in the four groups treated with quartz/PVNO, amorphous SiO2, carbon black and coal was achieved. A 2.5- to 7.7-fold increase for lactate dehydrogenase (LDH), total protein, alkaline phosphatase and gamma-glutamyl transferase (gamma-GT) was found in these groups as compared to the control. In contrast, quartz treatment without PVNO increased the LDH level up to 24-fold and of total protein to 13-fold. However, the cell counts in the BALF were not so much different in all five groups, i.e. quartz without PVNO (leukocytes: 480.000, PMN: 190.000), quartz with PVNO (leukocytes: 300.000, PMN: 100.000), amorphous SiO2 (leukocytes: 570.000, PMN: 315.000), carbon black (leukocytes: 390.000, PMN: 150.000) and coal (leukocytes: 200.000, PMN: 65.000). Histopathological investigations after four weeks and three months revealed that the used PVNO sample was active in the quartz and amorphous SiO2 groups and markedly reduced the incidences or severity of several pulmonary changes such as macrophage accumulation, inflammatory cell infiltration, interstitial fibrosis, bronchiolo-alveolar hyperplasia, alveolar lipoproteinosis and amorphous SiO2 -induced granulomatous alveolitis/interstitial fibrotic granulomas. Also in the lung-associated lymph nodes (LALN), PVNO treatment significantly reduced the incidence and severity of inflammation in both quartz and amorphous SiO2 groups as evidenced by the presence of well-circumscribed aggregates of intact particle-laden macrophages without signs of degeneration and accompanying granulocytic infiltration and fibrosis. Immunological investigations at the 9 months timepoint on the in vitro production of reactive nitrogen (RNI) or oxygen (ROI) intermediates and tumour necrosis factor (TNF-alpha) from BALF-derived cells indicated a diminished responsiveness to LPS in all particle treatment groups. A diminished production of ROI was also found in the quartz, carbon black, and coal dust groups, respectively, as compared to the values seen in the quartz/PVNO- and amorphous SiO2 treated groups. Treatment with quartz plus PVNO restored the capability of the cells to respond to LPS as compared to the treatment with quartz alone. TNF-alpha production was diminished in the groups treated with quartz, carbon black, and coal dust alone whereas in the quartz/PVNO- and amorphous SiO2-treated groups an elevated TNF-alpha production was seen. These results led to the conclusion that only amorphous SiO2 did not affect the "normal" ability of the cells to respond to LPS and that PVNO protected the cells from a toxic effect of the quartz particles.

DNA damage in lung epithelial cells isolated from rats exposed to quartz: role of surface reactivity and neutrophilic inflammation.

Respirable quartz has been classified as a human lung carcinogen (IARC, 1997). However, the mechanisms involved in quartz-induced carcinogenesis remain unclear. The aim of the present study was to investigate acute DNA damage in epithelial lung cells from rats exposed to quartz. Since surface reactivity is considered to play a crucial role in the toxicity of quartz, the effect of surface modifying agents polyvinylpyridine-N-oxide (PVNO) and aluminium lactate (AL) was evaluated. Therefore, rats were instilled with quartz (DQ12, 2 mg/rat) or quartz treated with PVNO or AL. After 3 days animals were killed and brochoalveolar lavage (BAL) was performed to evaluate inflammatory cell influx. BAL-fluid levels of lactate dehydrogenase (LDH), alkaline phosphatase (AP) and total protein were used as lung damage markers. Neutrophil activation was assessed by myeloperoxidase (MPO) measurement, and total antioxidant capacity of the BAL-fluid was determined using the TEAC (trolox equivalent antioxidant capacity) assay. Lung epithelial cells were isolated and DNA strand breakage was determined by single cell gel electrophoresis (comet assay). DNA damage was significantly increased in epithelial cells from rats instilled with DQ12, whereas no enhanced DNA strand breakage was observed when quartz was treated with PVNO or AL. Total protein, LDH and TEAC were increased in rats treated with native quartz, and this was inhibited by both coatings. A significant correlation between neutrophil numbers and MPO levels was observed, indicating neutrophil activation. Inhibition of DNA damage by both coatings was paralleled by a reduction of neutrophil influx as well as MPO activity. In this study we provide evidence that modification of the particle surface prevents DNA strand breakage in epithelial lung cells from quartz-exposed rats. Furthermore, the present data show the feasibility of our in vivo model to evaluate the role of inflammation, antioxidant status, and cytotoxicity in particle-induced DNA damage.

[Application and analysis of biochemical indices for the evaluation of antisilicosis treatment. Study on anti-silicosis therapy and its evaluation research group].

The levels of serum Ceruloplasmin (Cp), Superoxide dismutase (SOD) and IgG of 296 silicosis patients treated by tetrandrine, polyvinylpridine-N-Oxide, hydroxypiperaquinoline phosphate and aluminium citrate were measured. Sera were collected before and after the 1st, 3rd and 6th therapy courses. 144 Silicosis patients without treatment were observed as controls. The levels of these three indices decreased by the end of treatment. The levels of SOD were fluctuated, which were increased after the 3rd course, but decreased after the 1st and 6th courses. The decrease of Cp, SOD and IgG consisted with the clinical effectiveness of the treatment, indicating that Cp, SOD and IgG were appropriate biochemical indicators for the evaluation of antisilicosis drugs. The quality control and the statistics standardization for data analysis are important.

Studies on the toxic effects of quartz and a mycobacterial glycolipid, trehalose 6,6'-dimycolate.

Quartz and trehalose 6,6'-dimycolate (TDM) both potentiate tuberculosis and have toxicities that depend on surface crystalline structures. Investigations were undertaken to determine if TDM can kill macrophages and produce hemolysis in a fashion similar to that of quartz and if quartz can induce granulomas similar to those induced by TDM. Trehalose 6,6'-dimycolate was spread as a molecular monolayer on the surface of tissue culture dishes adjacent to areas of uncoated plastic for comparison. Murine peritoneal macrophages were killed within hours by contact with the TDM monolayer, while those on adjacent areas of uncoated plastic remained viable and spread normally. The membranes of erythrocytes were also damaged by contact with the monolayer of TDM. This damage was inhibited by poly-2-vinyl-pyridine-N-oxide, an inhibitor of hydrogen bonding that blocks quartz induced hemolysis. These data suggest that TDM damages membranes via an adhesive mechanism similar to that of quartz. Furthermore, injections of quartz particles into mice induce acute granulomatous reactions similar to those induced by TDM. These data indicate that TDM and quartz have certain similarities in their mechanisms of action and that these similarities may be of importance in the pathogenesis of tuberculosis.

A biochemical study on combined treatment of experimental silicosis with tetradrine-PVNO and tetradrine-QOHP in rats.

A better understanding is needed to explain the mechanism of therapeutic effect of combined use of tetradrine-PVNO and tetradrine-QOHP which play very important roles in treatment of silicosis. Blood prolidase (PLD), monamine oxidase (MAO) and plasminogen (PLG) in silicotic rats after treatment with tetradrine-PVNO or tetradrine-QOHP were measured. The values obtained were compared with the untreated silicotic rats. It was found that the silicotic rats that received tetradrine-PVNO showed significant increase in PLD and decrease in PLG, but no significant change in MAO. The PLD in plasma of silicotic rats that received tetradrine-QOHP were elevated significantly, but PLG and MAO did not change appreciably. These findings suggest that the combined use of tetradrine-PVNO and tetradrine-QOHP can accelerate the degradation of collagen in silicotic rats.

The effects of tetrandrine (TT) and polyvinylpyridine-N-oxide (PVNO) on gene expression of type I and type III collagens during experimental silicosis.

In the screening tests of drugs for silicosis in our laboratory, we found that TT, a type of alkaloid isolated from Stephania tetrandra, could inhibit the development of experimental silicosis of rats and the synthesis of collagen in rat lung. Chest X-rays of silicotic patients treated with TT for 1-3 years showed obvious changes. The silicotic nodules became smaller and shadows became clearer. PVNO was proved to have anti-silicotic effect on animal and clinically. This presentation reports the effect of them on collagen mRNA. Dot blot results showed that alpha 1 (I) and alpha 1 (III) mRNA levels increased significantly at 60 and 120 days after the rats were exposed to silica dust. The mRNA levels went down at 1 and 3 months after treated by TT and PVNO. In situ hybridization observation revealed that the silver grains of Type I and Type III collagen were scattered within the fibroblasts in cellular nodules and in thickened interstitium of silicosis tissue. The amounts of mRNA silver grains decreased in the lung tissue treated by TT and PVNO. It was suggested that TT and PVNO may inhibit the gene expression of collagen during silicosis.

Diminished arachidonic acid metabolite release by bovine alveolar macrophages exposed to surface-modified silica.

Modification of the silica surface has been shown to reduce its cytotoxicity in vitro and its fibrogenic activity in vivo. We have shown silica to be a potent stimulator of arachidonic acid (AA) metabolism in bovine alveolar macrophages (BAM). To determine the effect of surface-modified silica on AA metabolism in BAM, we exposed BAM in vitro to silica treated with aluminum lactate or polyvinylpyridine-N-oxide (PVPNO). BAM were prelabeled with [3H]AA and incubated with 3 and 5 mg of silica. Unmodified silica at these doses elicited maximal AA metabolite release from BAM. AA metabolites were analyzed by high performance liquid chromatography. Lactate dehydrogenase release was quantitated to determine the cytotoxicity of treated and untreated silica on BAM. Treating silica with aluminum lactate or PVPNO significantly (P less than or equal to 0.05) reduced 5-lipoxygenase metabolite release and significantly (P less than or equal to 0.05) increased cyclooxygenase metabolite release. These changes in AA metabolite release were accompanied by a significant (P less than or equal to 0.05) reduction in the cytotoxicities of the treated silicas compared with untreated silica. Our results suggest that the reduced inflammatory and fibrogenic activity of surface-modified silica may in part be due to reduced AA metabolite release from exposed macrophages.

Polyvinylpyridine-N-oxide and carboxymethyl cellulose inhibit mineral dust-induced production of reactive oxygen species by human macrophages.

Polyvinylpyridine-N-oxide (PVPNO) and carboxymethyl cellulose (CMC) are known to inhibit the cytotoxic effects of quartz particles and chrysotile asbestos fibers, respectively. The effect of PVPNO and CMC on mineral dust-induced production of reactive oxygen species (ROS) by human monocyte-derived macrophages was studied using lucigenin-dependent chemiluminescence. Ten micrograms of PVPNO inhibited the ROS production induced by 100 micrograms of quartz completely, but caused only 25% inhibition of the response to 100 micrograms of chrysotile. Ten micrograms of CMC inhibited the chrysotile-induced ROS production to 70%, but had a weak effect on the responses to quartz. Neither PVPNO nor CMC caused any inhibition of the ROS responses to serum-opsonized zymosan. PVPNO was bound to both quartz and chrysotile, but no binding of CMC to either dust could be detected. Neither PVPNO nor CMC had any superoxide scavenging effect. In conclusion, PVPNO and CMC seem to selectively modify mineral dust surface properties, which are of importance in the induction of ROS production by phagocytes. These observations may be useful in describing the pathogenesis of mineral dust-induced diseases, and may also have therapeutic implications.

[Studies on serum angiotensin-I-converting enzyme activity of experimental silicosis in rats].

The level of serum angiotensin-I-converting enzyme (SACE) activity on experimental silicosis in rats at different stages and under treatment with PVNO is reported. The results showed that levels of SACE in each dust groups begun to rise significantly higher than control groups as from the fifth day until 180th day (P less than 0.05). The levels of SACE of treatment groups with PVNO were significantly lower than the dust groups and similar to normal groups of the same age. It is suggested that SACE activity might be used as a reference index of silicosis.

Effect of two particle surface-modifying agents, polyvinylpyridine-N-oxide and carboxymethylcellulose, on the quartz and asbestos mineral fiber-induced production of reactive oxygen metabolites by human polymorphonuclear leukocytes.

We studied the capacity of quartz and asbestos fibers to induce the generation of reactive oxygen metabolites in human polymorphonuclear leukocytes (PMNs) with a chemiluminescence (CL) assay. On an equal weight basis, the particulates induced CL in the following order of magnitude: chrysotile, quartz greater than amosite, crocidolite, greater than anthophyllite, wollastonite. The intensity of CL correlated positively with the Alcian blue (a cationic dye) binding capacity of the particles. Polyvinylpyridine-N-oxide (0.5 microgram/ml) inhibited completely the CL induced by quartz but had little effect on the CL induced by asbestos fibers. Carboxymethylcellulose (1.0 microgram/ml), however, reduced the CL caused by chrysotile asbestos but had no effect on the CL induced by the other particulates. Our results suggest that in addition to length and diameter, the effect of quartz and asbestos fibers on inflammatory cells will depend on surface characteristics, including the charge of the particles.

[Inhalation treatment of silicosis with Kexiping]. / Inkhalatorno lechenie na silokozata s Keksiping.

The inhalation treatment of silicosis with polyvinyl-pyridine-oxide of molecule weight about 90,000 under the name Kexiping is the most perspective method at the moment for etiological effect of the silicotic fibrosis. The authors performed two 6-week inhalation course with interval of 6 months with 38 ill with silicosis. The daily dose 10 ml of 4% solution of Kexiping "Bayer". The first results alone and in comparison with the control group of 50 patients are very encouraging. The tolerance to the preparation is excellent, with no side effects or unfavourable deviations in the paraclinical indices. Further extensive, therapeutic applications and inhalation prophylaxis with healthy persons subject to high dust risk are completely justified. For final evaluation of the long-term effect a continuous observation of both treated and controls is necessary.

Carcinogenicity studies on natural and man-made fibres with the intraperitoneal test in rats.

Female Wistar rats were injected intraperitoneally (i.p.) with a suspension of 11 fibrous and 3 granular dusts. A dose of 0.25 mg actinolite or UICC chrysotile induced tumours of the peritoneum in more than 50% of the animals. Even 0.05 and 0.01 mg proved to be carcinogenic, although no adhesions of the abdominal organs could be observed. The findings are in conflict with the hypothesis that a scar is always the morphological precondition for the development of an asbestos-induced tumour. Actinolite injected i.p. in a solution of polyvinylpyridine-N-oxide gave a lower tumour incidence than when suspended only in saline, possibly due to inactivation of the fibre surface. Persistent glass fibres were less effective than actinolite having a similar fibre size distribution. On the other hand, relatively thick basalt fibres and ceramic fibres gave higher tumour incidences than expected. Wollastonite fibres were not carcinogenic, probably because of their low durability. Large amounts of polyvinylchloride, alpha-ferric oxide hydrate and wood dust also led only to adhesions of the abdominal organs and fibrosis; a definite carcinogenic effect was not detected.

Quartz-dust-induced production of reactive oxygen metabolites by human granulocytes.

We studied the effect of quartz on the production of reactive oxygen species by human polymorphonuclear leukocytes (PMN) in vitro by a chemiluminescence (CL) assay. Quartz caused a rapid dose-dependent CL response in the cells. Diamond dust used as an inert control did not stimulate the production of reactive oxygen metabolite by PMN. The quartz-induced activation of oxygen metabolism was also demonstrated by measuring oxygen consumption, nitroblue tetrazolium reduction, and superoxide and hydrogen peroxide production by PMN. Poly-vinyl-pyridine N-oxide (a quartz surface modifying agent) completely abolished the quartz-induced response, but had no effect on opsonized zymosan-induced CL response of PMN. The effect of N-acetylcysteine (a known antioxidant) was inhibitory to the CL formation induced by both quartz and opsonized zymosan. Our results are in agreement with the hypothesis that quartz-induced production of reactive oxygen metabolites is a possible mechanism by which quartz dust produces chronic inflammation and tissue injury of the lung. Agents interfering with the generation of reactive oxygen metabolites may provide a rationale for treatment of mineral-dust-induced pulmonary disease.

Sustained release of a model macromolecule from preparations with erodible core.

A series of sustained release tablets were prepared which consisted of a water-soluble core and a highly hydrophobic coat. Release of a macromolecule, Spectrum Orange, from this preparation was studied. It was found that release was controlled by the coat composition and coating solution viscosity. SEM and optical microscopy of the tablets indicated that the coats contained pores on the surface which penetrated in towards the centre of the core. It was deduced that the almost zero order release of macromolecules from these tablets was basically through these pores and not by diffusion through the polymer matrix.

Titanium dioxide induced chemiluminescence of human polymorphonuclear leukocytes.

The ability of different titanium dioxides (TiO2) to induce production of reactive oxygen metabolites by human polymorphonuclear leukocytes was studied. Pure rutile or anatase preparations show only a weak chemiluminescent response. Surface-modified TiO2 causes a strong chemiluminescent response with a biphasic configuration resembling that of quartz. Sonication of the dust suspensions resulted in a strong enhancement of the chemiluminescent response, with each dust preparation showing approximately equal maximal activity. However, coated TiO2 still exhibited a different mode of cell activation. The chemiluminescence-inducing activity of the different TiO2 studied did not correlate with their hemolytic activity. As polyvinyl-pyridin-N-oxide (PVPNO) inhibits the chemiluminescence induced by coated TiO2 samples, it seems that both particle size and surface structure determine the mode and intensity of activation of human PMNL by TiO2. The results point out the need for in vivo testing and comparison of different TiO2 preparations.