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PubMed1991

Control of American cockroaches (Dictyoptera: Blattidae) in sewers.

Baits, dusts, and aqueous sprays were applied to sewer shafts to control American cockroaches, Periplaneta americana (L). Boric acid and hydramethylnon baits failed to provide consistent control because of problems with mold on the baits and because large populations of cockroaches depleted the bait. Bendiocarb, boric acid powder, and a powder mixture of silica gel + synergized pyrethrins provided excellent control for at least 1 mo, but cockroaches reinfested treated shafts within 3-6 mo. Treatments made in the fall when adult cockroach populations were lowest (about 26%) provided best results. Aqueous sprays of wettable powder chlorpyrifos and microencapsulated diazinon provided outstanding control for at least 9 mo. Microencapsulated and emulsifiable concentrate chlorpyrifos sprays provided greater than 94% reductions for a year.

Animals↗
PubMed1993

Reduction of nymphal Ixodes dammini (Acari: Ixodidae) in a residential suburban landscape by area application of insecticides.

Seven formulations of three commercially available insecticides were evaluated for their ability to reduce the density of nymphal deer ticks (Ixodes dammini Spielman, Clifford, Piesman & Corwin) in a suburban residential area endemic for Lyme disease. In total, 101 residential properties in Mount Kisco, Westchester County, NY, were treated with one of the following: carbaryl emulsifiable concentrate (EC) at 0.6 or 1.1 kg AI/ha, carbaryl granular (GR) at 4.5 kg AI/ha, chlorpyrifos wettable powder (WP) at 0.6 or 1.1 kg AI/ha, chlorpyrifos GR at 1.1 kg AI/ha, or cyfluthrin EC at 0.1 kg AI/ha. All three chemicals were found to reduce the density of nymphs on treated properties significantly compared with untreated controls. Percentage of reduction of nymphs ranged from 67.9% for carbaryl EC 1.1 kg AI/ha to 97.4% for chlorpyrifos WP 1.1 kg AI/ha. There was no difference in the amount of reduction provided by each formulation of the same chemical, but carbaryl formulations were significantly less effective than chlorpyrifos or cyfluthrin. Nymphal densities after treatment remained low throughout the course of the study, indicating that a single well-timed spring application is sufficient to provide significant reduction of nymphs for an entire transmission season.

Animals↗
PubMed1995

Reduction of immature Ixodes scapularis (Acari: Ixodidae) in woodlots by application of desiccant and insecticidal soap formulations.

The efficacy of two commercially available formulations of a desiccant and insecticidal soap were compared with chlorpyrifos wettable powder (0.6 kg [AI]/ha) against the immatures of Ixodes scapularis Say in a woodlot in Westchester County, New York. The desiccant formulation (Drione) was applied at 61.04 kg/ha and an insecticidal soap (Safer's) was applied as a mixture (39 ml concentrate per liter of water) at 107 liters/ha. By 1 wk after application, all treatments significantly reduced the density of nymphs in comparison to untreated plots. Only plots treated with chlorpyrifos had significantly reduced nymphal densities 2 wk after application. By 6 wk after application, there were no differences in nymphal density between treated and untreated plots, which was likely the result of a decline in overall nymphal populations. None of the treatments against nymphs affected larval densities sampled 6 wk after application. Larval density was significantly lower 1 wk after application in plots treated with chlorpyrifos and Safer's insecticidal soap than in untreated plots. By 2 wk after treatment, only plots treated with chlorpyrifos had lower larval densities than untreated plots. Results indicate that the desiccant Drione and Safer's insecticidal soap are good for short-term control of immature I. scapularis.

Analysis of Variance↗
PubMed2003

Impact of surface chemistry and blocking strategies on DNA microarrays.

The surfaces and immobilization chemistries of DNA microarrays are the foundation for high quality gene expression data. Four surface modification chemistries, poly-L-lysine (PLL), 3-glycidoxypropyltrimethoxysilane (GPS), DAB-AM-poly(propyleminime hexadecaamine) dendrimer (DAB) and 3-aminopropyltrimethoxysilane (APS), were evaluated using cDNA and oligonucleotide sub-arrays. Two un-silanized glass surfaces, RCA-cleaned and immersed in Tris-EDTA buffer were also studied. DNA on amine-modified surfaces was fixed by UV (90 mJ/cm(2)), while DNA on GPS-modified surfaces was immobilized by covalent coupling. Arrays were blocked with either succinic anhydride (SA), bovine serum albumin (BSA) or left unblocked prior to hybridization with labeled PCR product. Quality factors evaluated were surface affinity for cDNA versus oligonucleotides, spot and background intensity, spotting concentration and blocking chemistry. Contact angle measurements and atomic force microscopy were preformed to characterize surface wettability and morphology. The GPS surface exhibited the lowest background intensity regardless of blocking method. Blocking the arrays did not affect raw spot intensity, but affected background intensity on amine surfaces, BSA blocking being the lowest. Oligonucleotides and cDNA on unblocked GPS-modified slides gave the best signal (spot-to-background intensity ratio). Under the conditions evaluated, the unblocked GPS surface along with amine covalent coupling was the most appropriate for both cDNA and oligonucleotide microarrays.

DNA, Complementary↗
PubMed1999

Ceramic bearing surfaces.

Despite more than 25 years of clinical experience with ceramic materials as bearing surfaces, their role in modern joint replacement surgery remains to be clearly defined. The two primary materials are alumina and zirconia. The application of these materials is primarily as a femoral head bearing surface against polyethylene, but alumina also is used as a femoral head and an acetabulum to provide a polyethylene-free bearing surface. Important issues that must be clarified for these materials to gain wide acceptance are the material properties, wear rates against polyethylene and alumina, the biologic response to ceramic wear debris, and cost in relation to indications. The bulk materials are biocompatible, hard, wettable, high-strength, and can yield good surface finishes. Linear polyethylene wear against alumina heads is reported to be as much as a factor of 5 to 10 lower than metal versus polyethylene. Thus, the ceramic femoral head may be a good choice for the younger patient in whom it seems necessary to use a larger head for stability reasons with a polyethylene cup. Ceramic-on-ceramic wear rates are in the range of 0.003 mm/year, a factor of 10 less than the lowest polyethylene wear rates. These costly materials are limited in head and neck sizes because of statistical variation in strength that can lead to fracture. Occasional reports of high alumina-on-alumina wear have appeared. Many of the problems of the past have been design, manufacture, or application related, and have been improved or eliminated. Proper clinical technique in the use of ceramic femoral heads is crucial to prevent fracture. The materials hold high promise and should continue to be used so that additional experience can help define the clinical indications for components made of these materials.

Arthroplasty, Replacement, Hip↗
PubMed1993

Characterization of water retentive properties of hyaluronan.

We examined the water retentive properties of hyaluronan because of its reported therapeutic effect in the treatment of dry eye. Hyaluronan dose dependently retarded water loss from a solution kept at constant temperature and humidity. Similarly, water loss was retarded when hyaluronan was placed atop an agar gel. These decreases in water loss were not related to changes in the molecular weight of hyaluronan. Unlike the in vitro models, the evaporation rate from the tears in normal subjects initially increased following the topical application of hyaluronan, and continued a higher rate than with the vehicle. These results suggest that hyaluronan enhances water retention on the corneal surface, and probably increases corneal wettability. Accordingly, hyaluronan eye drops may be useful in the treatment of dry eye.

Desiccation↗
PubMed1996

Do thinner rigid gas permeable contact lenses provide superior initial comfort?

To test the hypothesis that thinner rigid gas permeable (RGP) contact lenses provide superior initial comfort, RGP lenses of 3 center thicknesses, 0.08, 0.12, and 0.16 mm, in otherwise matched parameters, were worn for 30 min by 17 unadapted subjects in a controlled, double masked, randomized study. Comfort ratings (0 to 100) after 30 min of wear were 42 +/- 30, 55 +/- 27, and 57 +/- 28 for the 0.08-, 0.12-, and 0.16-mm thick lenses, respectively (p = 0.04, multiple analysis of variance (MANOVA)), and 93 +/- 13 for the hydrogel control lens. The thinnest RGP lens was significantly less comfortable than its thicker counterparts (p = 0.03, Univariate F-test). There were no differences among the test lenses in edge shape, front surface wettability, or static lens fittings, and small differences in movement, vertical decentration, and front surface geometry were not significantly related to comfort. We hypothesize that the greater flexibility of the thinnest lens resulted in greater deformation of the lens during a blink cycle, causing transient peripheral lens lifting and interaction with the upper eyelid, thereby reducing comfort. In conclusion we found that thinner RGP lenses do not provide an initial comfort advantage and that very thin and, as a corollary, very flexible, RGP lenses can actually be less comfortable initially than stiffer, but otherwise matched, designs.

Adolescent↗
PubMed2001

Superior epithelial arcuate lesions with soft contact lens wear.

BACKGROUND: Superior epithelial arcuate lesions (SEALs) are an infrequent and often asymptomatic complication of conventional soft contact lens wear. The characteristic arcuate pattern of the full-thickness corneal epithelial lesion usually occurs in the area covered by the upper eyelid, within 2 to 3 mm of the superior limbus in the 10- and 2-o'clock region. METHODS: Literature on SEALs and recent clinical records from clinical trials using two types of prototype high Dk soft contact lenses were reviewed to gain greater insights into the etiology of SEALs. RESULTS AND CONCLUSIONS: The reported low incidence of SEALs is partly because SEALs are not usually symptomatic. The etiology of SEALs is multifactorial. Our current hypothesis is that SEALs are produced by mechanical chaffing at the peripheral cornea. This chaffing occurs as a result of inward pressure of the upper lid, in an area where the peripheral corneal topography and lens design, rigidity, and surface characteristics combine to create excessive "frictional" pressure and abrasive shear force on the epithelial surface. Patient characteristics such as gender, age, and specific corneal and lid topographies also appear to influence the occurrence of SEALs. Prototype silicone hydrogel lenses are made from higher modulus materials with surfaces that seem to differ subtly in wettability in some patients. The prevalence of SEALs may well increase with the first generations of these lenses.

Clinical Trials as Topic↗
PubMed2003

Corneal desiccation in rigid contact lens wear: 3- and 9-o'clock staining.

The current knowledge of treatment options together with signs and symptoms, classification, prevalence, and etiology of 3- and 9-o'clock staining in rigid contact lens wear are described in this review article. In total, 11 treatment options for the management of 3- and 9-o'clock staining were found in the literature. Five of these treatment options are related to lens parameters, namely edge lift, edge thickness and shape, back surface geometry, total diameter, and back optic zone radius. Three other options are related to lens performance: movement, centration, and surface wettability. Three more variables can be identified: blinking habits, tear supplements, and, finally, switching to a hydrogel material. There is controversy on how to adjust the most important individual variables for management of 3- and 9-o'clock staining. The advocated treatment options are often related to the fitting techniques used: lid attachment or interpalpebral fit. Implications for practice and for further research are discussed.

Contact Lenses↗
PubMed2003

Preservative-free ocular hydrating agents in symptomatic contact lens wearers: saline versus PVP solution.

PURPOSE: To compare two preservative-free hydrating agents, in multidose (ABAK) bottles, in contact lens wearers experiencing symptoms of ocular dryness. METHODS: The endpoint of this 4-week multicenter, randomized, double-blind, parallel-group study comparing a 2% polyvinylpyrrolidone (PVP) solution with a 0.9% NaCl solution was to assess ocular discomfort using a visual analog scale. A biomicroscopic examination and a test of tolerability on instillation were also performed, and adverse events were recorded. RESULTS: Thirty-nine subjects were enrolled (23 PVP; 16 NaCl). The average age was 30; subjects were predominantly female, and mostly wore frequent-replacement contact lenses. They were all exposed to environmental factors such as routine use of video monitors or air conditioning. The two groups were similar at baseline (D0). Both PVP and NaCl improved the comfort of contact lens wear (P = 0.0003), with no difference between them (P = 0.25). The mean daily duration of lens wear and the daily number of instillations to relieve discomfort (4.2 +/- 2.0 for PVP ABAK; 4.6 +/- 1.9 for NaCl ABAK) were comparable. However, PVP use led to more favorable evolution of fluorescein-staining corneal punctuations (P = 0.028). Safety was good, with minimal adverse events considered unrelated to the products. Lens wettability was excellent, and there were no clinically relevant deposits. Most subjects also found the ABAK bottles convenient. CONCLUSIONS: Ocular hydration improves comfort in contact lens wearers. NaCl is an appropriate first-line treatment, but for subjects with fluorescein-staining punctuations, lubrication with PVP is preferable.

Adult↗
PubMed2005

Sealer penetration and apical microleakage in smear-free dentin after a final rinse with either 70% isopropyl alcohol or Peridex.

Tensioactive agents may alter dentinal wettability allowing increased sealer penetration into dentinal tubules. This may improve the apical seal and better entomb remaining bacteria. The purpose of this study was to determine if a final rinse with either 70% isopropyl alcohol or Peridex in instrumented, smear-free canals would affect apical microleakage or Roth's 801 sealer penetration into dentinal tubules. Sixty root segments were instrumented followed by smear layer removal. The segments were randomly divided into three groups receiving a final rinse with 6% sodium hypochlorite (NaOCl), 70% isopropyl alcohol or Peridex. Obturation was completed using lateral compaction and Roth's 801 sealer pigmented with carbon black. Microleakage was measured by fluid filtration. Sealer penetration was measured using light microscopy. No significant differences were found between groups for microleakage or sealer penetration. Although a final rinse with either 70% isopropyl alcohol or Peridex did not increase sealer penetration, neither significantly affected apical microleakage compared to NaOCl.

2-Propanol↗
PubMed2004

Comparison of the performance of 6- or 30-night extended wear schedules with silicone hydrogel lenses over 3 years.

AIM: To compare the clinical performance of silicone hydrogel lenses worn for 6- or 30-nights, with monthly replacement, for 3 years. METHODS: In this 3-year prospective clinical trial, 161 subjects were enrolled and 154 commenced extended wear. Clinical performance was assessed by comparing discontinuations and lens surface characteristics (front surface deposits, lens wettability, number of mucin balls), lens fitting performance (primary gaze movement, lens tightness), and physiologic parameters (limbal and bulbar redness, corneal and conjunctival staining, microcysts) and subjective parameters (ratings of comfort and vision) between groups. RESULTS: Eighty-eight subjects remained in the study after 36 months. There were no differences in the probability of subjects surviving in either group, and the major cause of lens-related discontinuation in both groups was contact lens-induced papillary conjunctivitis. There were no clinically important differences in performance between wear schedules. CONCLUSION: The long-term clinical performance of silicone hydrogels worn for 6- or 30-nights continuously was similar. Clinical markers of hypoxia were low in both groups, and the 6-night wear schedule was not superior to the 30-night wear schedule with regard to preventing lens spoilage, improving corneal physiology, or subjective symptoms of comfort and vision.

Adult↗
PubMed1994

Attachment of staphylococci to different plastic tubes in vitro.

Adherence of 18 staphylococcal strains to 13 types of uncoated plastic tubes made from 10 different plastic materials were investigated by binding of radiolabelled bacteria in phosphate-buffered saline for 2 h at 37 degrees C. The different materials could be divided into five groups based on their ability to bind staphylococci. Lowest adhesion was found for plasticised polyvinylchloride. Simple assays for the relative binding of peroxidase-labelled human IgG or fibrinogen did not predict the result of adhesion studies. Neither bacterial surface hydrophobicity measured in a two-phase partitioning assay, nor hydrophobicity of materials (wettability) as measured by their contact angles in water correlated with bacterial adhesion. Adhesion of staphylococci to certain plastic materials was greatly influenced by the method used for sterilisation of the material.

Bacterial Adhesion↗
PubMed2006

Repellents have functionally replaced hydrophobins in mediating attachment to a hydrophobic surface and in formation of hydrophobic aerial hyphae in Ustilago maydis.

Ustilago maydis contains one repellent and two class I hydrophobin genes in its genome. The repellent gene rep1 has been described previously. It encodes 11 secreted repellent peptides that result from the cleavage of a precursor protein at KEX2 recognition sites. The hydrophobin gene hum2 encodes a typical class I hydrophobin of 117 aa, while hum3 encodes a hydrophobin that is preceded by 17 repeat sequences. These repeats are separated, like the repellent peptides, by KEX2 recognition sites. Gene hum2, but not hum3, was shown to be expressed in a cross of two compatible wild-type strains, suggesting a role of the former hydrophobin gene in aerial hyphae formation. Indeed, aerial hyphae formation was reduced in a Delta hum2 cross. However, the reduction in aerial hyphae formation was much more dramatic in the Delta rep1 cross. Moreover, colonies of the Delta rep1 cross were completely wettable, while surface hydrophobicity was unaffected and only slightly reduced in the Delta hum2 and the Delta hum2 Delta hum3 cross, respectively. It was also shown that the repellents and not the hydrophobins are involved in attachment of hyphae to hydrophobic Teflon. Deleting either or both hydrophobin genes in the Delta rep1 strains did not further affect aerial hyphae formation, surface hydrophobicity and attachment. From these data it is concluded that hydrophobins of U. maydis have been functionally replaced, at least partially, by repellents.

Crosses, Genetic↗
PubMed1992

Developmental and light regulation of eas, the structural gene for the rodlet protein of Neurospora.

The surface of many fungal spores is covered by a hydrophobic sheath termed the rodlet layer. We have determined that the rodlet protein of Neurospora crassa is encoded by a cloned gene designated bli-7, and that bli-7 is identical to the known gene eas (easily wettable). Using eas DNA as a probe we show that eas mRNA is abundant in illuminated mycelia and conidiophores but is not detectable or is barely detectable in dark-grown mycelia, mature macroconidia, microconidia, and ascospores. Mutations in the genes acon-2, acon-3, and fl block early conidiophore development; of these, only fl prevents normal eas transcription. The EAS protein is homologous to the rodlet protein (RodA) of Aspergillus nidulans, and the hydrophobins of Schizophyllum commune. eas is the first cloned conidiation (con) gene of N. crassa that is associated with a phenotypic alteration.

Amino Acid Sequence↗
PubMed1992

The Neurospora circadian clock-controlled gene, ccg-2, is allelic to eas and encodes a fungal hydrophobin required for formation of the conidial rodlet layer.

The Neurospora crassa clock-controlled gene (ccg-2) is transcriptionally activated by the circadian clock in a time-of-day-specific manner. Transcript and sequence analyses of ccg-2 reveal that the predicted Ccg-2 polypeptide bears significant similarity to a class of low-molecular-weight, cysteine-rich, hydrophobic proteins (hydrophobins), first identified in Schizophyllum, and including the product of the developmentally regulated Aspergillus gene, rodletless, required for spore surface rodlets. Allelism between ccg-2 and easily wettable (eas) (one of the first developmental genetic loci identified in Neurospora) was predicted on the basis of this similarity, their close genetic linkage, and previous findings demonstrating that eas mutants lack rodlets. In this study allelism is confirmed experimentally by showing that (1) transformation of an eas mutant strain with ccg-2 DNA results in phenotypic complementation, including restoration of surface rodlets, (2) inactivation of the ccg-2 gene, by RIP, results in an eas phenotype including loss of rodlet fascicles, and (3) the original eas strain has dramatically reduced levels of ccg-2 mRNA. Thus, the clock-controlled ccg-2 gene encodes an integral component of fungal asexual spores important for spore dispersal. The dramatic reduction of ccg-2 expression in the eas mutant has no apparent effect on the normal operation of the circadian clock, confirming that there is no feedback of this clock output on the oscillator itself. These data, in conjunction with the previous observation that ccg-2 is light induced, serve to focus attention on the dual interacting role of light and the circadian clock in the regulation of fungal spore development.

Alleles↗
PubMed2000

Wetting-driven structure formation of a binary mixture in the presence of a mobile particle pinning potential

We investigate the pattern formation on the solid substrate of phase-separating films containing mobile wetting particles with a preferential attraction for one component of the mixtures. The presence of mobile particles under the surface-particle interaction modulation breaks the isotropy of the bulk phase-separating process, leading to the formation of orientational structure due to the interplay between phase separation and wetting particle ordering under a modulated pinning potential at the late stage. Simulations suggest that the phase-separation morphology can be changed through the adjustment of the wettable-phase-particle interaction and the surface-particle interaction. It provides some important insights into this "wetting-directed spinodal decomposition."

Journal Article↗
PubMed2002

Using patterned substrates to promote mixing in microchannels.

Using a lattice Boltzmann model for fluid dynamics, we investigate the flow and phase behavior of a binary fluid moving over a patterned substrate within a microchannel. The binary fluid consists of two immiscible components, A and B, and this liquid is subjected to a Poiseuille flow. The substrate is decorated with a checkerboard pattern of A- and B-like patches. Through a coupling of hydrodynamics and thermodynamics, each component is driven to flow from the nonwettable domains to wettable regions. As a consequence, the A and B fluids undergo extensive mixing within the microchannels. We investigate how the degree of mixing depends on the size of the patches, the velocity of the imposed flow field, and the characteristics of the fluid. The results provide guidelines for creating localized "mixing stations" within microfluidic devices. The findings also reveal how a combination of imposed flow fields and surface patterning can be exploited to control the phase behavior of complex fluids.

Journal Article↗