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Effectiveness of organic sunscreens is limited by phototoxicity and degradation. Both of which can be significantly reduced by encapsulation in hollow particles or covalent incorporation into the solid structure of particles, but direct comparisons of the two methods have not been reported. In this study, physical encapsulation and covalent incorporation of sunscreens were compared with 1 mol % salicylate and curcumeroid sunscreens. 2-Ethylhexyl salicylate was physically encapsulated in hollow silica nanoparticles prepared by oil-in-water (O/W) microemulsion polymerizations (E-Sal). Some of these particles were coated with an additional shell or cap of silica to reduce leaking of sunscreen (cap-E-Sal). Covalent incorporation involved co-polymerizing tetraethoxysilane (TEOS) with 0.2 mol % of new salicylate and curcuminoid sunscreen monomers with triethoxsilyl groups. Particles were prepared with the salicylate attached to the silica matrix through single silsesquioxane groups (pendant; P-Sal) and two silsesquioxane groups (bridged; B-Sal). Particles based on a new curcuminoid-bridged monomer were also prepared (B-Curc). Sunscreen leaching, photodegradation, and sunscreen performance were determined for the E-Sal, cap-E-Sal, P-Sal, B-Sal, and B-Curc particles. Covalent attachment, particularly with bridged sunscreen monomers, reduced leaching and photodegradation over physical encapsulation, even with capping.

Background Despite the significant decline in smoking rates in the USA over the last 50 years, 42 million Americans continue to smoke. Although the combination of behavioural counselling with FDA-approved medications offers the best evidence-based treatment approach, 12-month relapse rates remain at >60%. Both healthcare providers and patients are searching for alternative treatment options. Most acupuncture trials have yielded poor results for smoking cessation; however, most trials have not used an intense treatment protocol and maintained treatment for at least 12 weeks.Methods We designed a pilot study to address these methodological problems. Twenty-eight smokers were recruited to attend two 1 h acupuncture sessions weekly for 12 weeks. Primary endpoints included completion rate, acceptability of the protocol and side effects. Secondary endpoints included carbon monoxide (CO)-confirmed, 7-day point prevalence quit rates at 12 weeks and 26 weeks.Results Sixteen of the 28 patients enrolled (57%) completed 12 weeks of treatment. Of the 17 patients who completed the end-of-study questionnaire, 94% (16/17) rated the programme as helpful, and 82% noted they would recommend it to friends for smoking cessation. Three of the 28 who initially enrolled in the study were confirmed abstinent at 12 weeks (10.7%); one of the 28 (3.6%) was abstinent at 26 weeks.Conclusions A larger study with a slightly less rigorous and more acceptable treatment protocol is feasible and should be considered.

Epoxies are commonly used in art conservation as adhesives for artifact reconstruction and repair. However, with the development of colorless epoxies, it has become more difficult to detect repair work. Fluorescent epoxies would allow for easy detection of the epoxy joints by simple visual inspection under UV light while remaining unnoticeable under normal display lighting. Coumarins are natural dyes that can be added in very small amounts to make thermosets fluoresce. Depending on the functionality of the coumarin used, the dye may be physically encapsulated in the cross-linked polymer or it may be bound to the polymer through covalent bonds. In this paper, we examine the efficacy of coumarin (1) and coumarin 480 (2) as physically encapsulated dyes and 7-hydroxycoumarin (3) and 7-glycidyloxycoumarin (4) as covalently bound dyes in a commercial epoxy thermoset, Epo-Tek 301. All four dyes could be used to make the epoxy fluorescent, but coumarins 1and 2slightly reduced the lap shear strength of the thermoset and could be extracted with solvent. In contrast, coumarins 3and 4had little effect on the mechanical properties of the epoxy and only minute amounts could be extracted.

Perilymph gusher (PG) is a very rare occurrence that can lead to an adverse outcome during inner ear surgery. In the absence of a family history of X-linked mixed deafness syndrome, surgeons may have difficulty determining if a patient is at risk preoperatively. Radiographic imaging is often performed in an attempt to identify such a possibility, but there are few data to support the value of negative studies. We conducted a retrospective study of 3 cases of PG in which findings on preoperative high-resolution computed tomography (CT) of the temporal bone had been interpreted as normal. We reviewed these CTs to discern if they did in fact demonstrate any abnormalities that might have indicated a risk of PG, and we found that the original radiologist had missed a dilated internal auditory canal and a deformity of the cochlear modiolus in the affected ear of 1 of these patients. No abnormality was detected on review of the CTs of the other 2 patients. Therefore, we conclude that negative CT findings do not necessarily rule out a risk of PG.

It would be medically and economically desirable to prevent the millions of annual extraintestinal infections and the thousands of associated deaths due to Escherichia coli. Outer membrane proteins are potential vaccine candidates for the prevention of these infections. This study tested the hypotheses that the siderophore receptor IroN is antigenic and that an IroN-specific antibody response confers protection in vivo. Subcutaneous immunization with denatured IroN resulted in a significant IroN immunoglobulin G (IgG)-specific response in serum (P < 0.0001) but not a systemic or mucosal IroN-specific IgA response. In a mouse model of ascending urinary tract infection, subcutaneous immunization with denatured IroN conferred significant protection against renal (P = 0.0135 and 0.0095 in two independent experiments), but not bladder, infection. These data, together with the previously demonstrated role of IroN in virulence, its expression in human biologic fluids, and its prevalence among extraintestinal pathogenic E. coli strains, support further studies on the role of IroN as a vaccine candidate.

ABSTRACTIt would be medically and economically desirable to prevent the millions of annual extraintestinal infections and the thousands of associated deaths due to Escherichia coli. Outer membrane proteins are potential vaccine candidates for the prevention of these infections. This study tested the hypotheses that the siderophore receptor IroN is antigenic and that an IroN-specific antibody response confers protection in vivo. Subcutaneous immunization with denatured IroN resulted in a significant IroN immunoglobulin G (IgG)-specific response in serum (P< 0.0001) but not a systemic or mucosal IroN-specific IgA response. In a mouse model of ascending urinary tract infection, subcutaneous immunization with denatured IroN conferred significant protection against renal (P= 0.0135 and 0.0095 in two independent experiments), but not bladder, infection. These data, together with the previously demonstrated role of IroN in virulence, its expression in human biologic fluids, and its prevalence among extraintestinal pathogenic E. colistrains, support further studies on the role of IroN as a vaccine candidate.

IroN was recently identified in the extracellular pathogenic Escherichia coli strain CP9. In this study experimental evidence demonstrating that IroN mediates utilization of the siderophore enterobactin was obtained, thereby establishing IroN as a catecholate siderophore receptor. In a mouse model of ascending urinary tract infection the presence of iroN contributed significantly to CP9's ability to colonize the mouse bladder, kidneys, and urine, evidence that IroN is a urovirulence factor. However, growth in human urine ex vivo and adherence to uroepithelial cells in vitro were equivalent for an isogenic mutant deficient in IroN (CP82) and its wild-type parent (CP9). Taken together, these findings establish that IroN is a siderophore receptor and a urovirulence factor. However, uncertainty exists as to the mechanism(s) via which IroN contributes to urovirulence.

A time-stepping model of a transversely vibrating, simply supported beam which allows the inclusion of non-linear damage such as a breathing crack is presented. It is based on the approximation that the mass and inertia of the beam may be lumped at points along the beam and the beam flexibility may be represented by discrete springs between rigid blocks. The advantage of a time-stepping approach over other models reported is that it enables the flexibility of the springs to be altered at any time during the analysis allowing the modelling of non-linear damage. The natural frequencies and mode shapes predicted by the model for an undamaged beam are validated against theoretical values and the representation of a non-linear mechanism in the model is compared with experimental data. The model predictions are shown to be accurate for both the undamaged and the non-linear cases.

Objectives: The purpose of the present study was to assess and describe the severity of symptoms reported by Covid-19 positive patients who vaped (smoked e-cigarettes) when compared to those who did not vape or smoke at the time of the diagnosis of Covid-19.Methods: Patients from this study are from a well-characterized patient cohort collected at Mayo Clinic between March 1, 2020 and February 28, 2021; with confirmed COVID-19 diagnosis defined as a positive result on reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assays from nasopharyngeal swab specimens. Among the 1734 eligible patients, 289 patients reported current vaping. The cohort of vapers (N = 289) was age and gender matched to 1445 covid-19 positive patients who did not vape. The data analyzed included: date of birth, gender, ethnicity, race, marital status, as well as lifestyle history such as vaping and smoking and reported covid-19 symptoms experienced.Results: A logistic regression analysis was performed separately for each symptom using generalized estimating equations (GEE) with robust variance estimates in order to account for the 1:5 age, sex, and race matched set study design. Patients who vaped and developed Covid-19 infection were more likely to have chest pain or tightness (16% vs 10%, vapers vs non vapers, P= .005), chills (25% vs 19%, vapers vs non vapers, P= .0016), myalgia (39% vs 32%, vapers vs non vapers, P= .004), headaches (49% vs 41% vapers vs non vapers, P= .026), anosmia/dysgeusia (37% vs 30%, vapers vs non vapers, P= .009), nausea/vomiting/abdominal pain (16% vs 10%, vapers vs non vapers, P= .003), diarrhea (16% vs 10%, vapers vs non vapers, P= .004), and non-severe light-headedness (16% vs 9%, vapers vs non vapers, P< .001).Conclusion: Vapers experience higher frequency of covid-19 related symptoms when compared with age and gender matched non-vapers. Further work should examine the impact vaping has on post-covid symptom experience.

The degree of soil development associated with geomorphic surfaces in the San Timoteo Badlands area (STB), California allows correlation of the surfaces. Soil development indices, based on field descriptions and laboratory analysis, provide a basis for comparison of these soils to each other and to dated soil chronosequences at Cajon Pass, Merced, and Anza, California. The soils in this study record a complex tectonic and climatic history, include preserved surfaces intermediate in soil development to those at Cajon Pass, and do not preserve a record of the major late Pleistocene to early Holocene aggradational event observed elsewhere in the region. Pedogenesis is similar to that of regional soils in southern California. With time, the profiles develop progressively thicker argillic horizons, and they increase in redness, clay, and secondary iron oxide content, and amount and thickness of clay films. With increasing soil age the ratio of dithionite-extractable Fe to total Fe increases, while the ratios of Fe2+to Fe3+and of oxalate- to dithionite-extractable Fe decrease. These trends are more subdued in the STB than elsewhere in the region, perhaps because the slightly higher temperature and lower precipitation of the STB may slow the rate of transformation of ferrihydrite to hematite. We use weighted means of soil development indices and rubification index values to compare the soils of this study to those at Cajon Pass, Merced, and Anza. Wide-range age estimates using the maximum limits of these values result in 27,500–305,000 yr for surface Q1, 43,000–570,000 yr for surface Q2, and 300,000–700,000 yr for surfaces Q3 and Q4. Weighing most heavily the nearest dated chronosequences, Anza and Cajon Pass, yields best estimates of age. This method constrains the time of formation of the Q1 surface to between 27,500 and 67,000 yr and the Q2 surface to 43,000–67,000 yr, and does not change the age estimates of the older surfaces.

Use of the orthogonal wavelet transform to detect abnormal transients generated by early gear damage from the gearbox casing vibration signal is discussed. Orthogonal wavelets, such as Daubechies 4 and harmonic wavelets, are used to transform the time domain synchronous vibration signal into the time-scale domain. The orthogonal wavelet transform uses fast algorithms and decomposes the signal onto the minimum number of wavelet series. However comparison with the non-orthogonal wavelet transform for the same length of discrete data shows that the description of the signal in the 3-dimensional map of the wavelet transform is not sufficiently comprehensive due to limited scales.

A system is described which uses image processing techniques to assist in the automatic interpretation of gear vibration signatures for early failure detection and fault diagnosis. The vibration signature of an individual gear in a gearbox is extracted by the time domain synchronous averaging technique from the total vibration signal measured on the gearbox casing. The time-frequency distribution of the gear vibration signature, determined from the spectrogram, is treated as an image, and the early failure detection and fault diagnosis are performed by interpreting the patterns in the image by the procedures of segmentation, connectivity analysis and feature extraction. The implementation of the technique, the criteria for analysis of the image, and experimental examples are described. Copyright 1993, 1999 Academic Press

The wavelet transform is used to represent all possible types of transients in vibration signals generated by faults in a gearbox. It is shown that the transform provides a powerful tool for condition monitoring and fault diagnosis. The vibration signal from a helicopter gearbox is used to demonstrate the application of the suggested wavelet by a simple computer algorithm. The major advantage of the wavelet transform for analyzing the signal is that it possesses multi-resolutions for localizing shirt-time components so that all possible types of gear faults can be displayed by a single time-scale distribution resulting from the transform.

Soils formed on alluvial fan deposits that range in age from about 35 000 to 200 yr BP near Silver Lake playa in the Mojave Desert permit study of the rates of soil development in an arid, hyperthermic climate. Field‐described properties of soils were quantified and analyzed using a soil development index that combines properties and horizon thicknesses. We compared the variability in index values from five independent descriptions of the same soil profile with the variability in values from four soils of the same age described by different people. The variability due to description accounts for between 30 and 80% of the total variability (that due to both the soils and description) for the properties described, which emphasizes the need for consistent soil descriptions. Pedogenic CaCO3(as indicated by color), pH increase, and dry consistence appear to change with age at linear rates, whereas rubification appears to change at a logarithmic rate. The linear rates are best attributed to the progressive accumulation of CaCO3‐ and salt‐rich eolian dust derived from the playa and other more distant sources. The total‐texture values of soils on fans older than 10 000 yr BP are similar, which suggests that playas in this area may have been wet enough to restrict the availability of fines from these sources for many thousands of years prior to 10 000 yr BP. Index values for most properties of soils on the lower fans adjacent to the playa increase at faster rates than those of soils of the same age on the upper fans farther from the playa, probably due to the proximity to this local dust source. Equations derived from regressions of soil age and properties can be used to estimate ages of undated, lithologically similar deposits in similar climates and geomorphic settings.

The vibration spectra of epicyclic gears commonly exhibit considerable asymmetry of the modulation sidebands and even complete suppression of the component at the tooth meshing frequency. A model is proposed which explains these observations in terms of the relationship between the vibrations generated by each of the planet gears as they move relative to the transducer location. Comparisons of the predictions of the model with measured vibration spectra for several epicyclic gearboxes show good agreement.

An approximate digital signal processing technique is presented which can assist in the early detection of local defects such as fatigue cracks in gears by enhancing the changes which these defects produce in the signal average of the vibration of the gear. The technique is demonstrated by the identification of an early fatigue crack in a helicopter gear. The importance of phase modulation in the detection of defects is indicated.

The use of acoustic emission transducers for the vibration monitoring of rolling element bearings at low speeds is explored. The frequency response and the base strain and bending sensitivities of the transducers are shown to be important.

Four soil chronosequences in the southern Great Basin were examined in order to study and quantify soil development during the Quaternary. Soils of all four areas are developed in gravelly alluvial fans in semiarid climates with 8 to 40 cm mean annual precipitation. Lithologies of alluvium are granite-gneiss at Silver Lake, granite and basalt at Cima Volcanic Field, limestone at Kyle Canyon, and siliceous volcanic rocks at Fortymile Wash. Ages of the soils are approximated from several radiometric and experimental techniques, and rates are assessed using a conservative mathematical approach. Average rates for Holocene soils at Silver Lake are about 10 times higher than for Pleistocene soils at Kyle Canyon and Fortymile Wash, based on limited age control. Holocene soils in all four areas appear to develop at similar rates, and Pleistocene soils at Kyle Canyon and Fortymile Wash may differ by only a factor of 2 to 4. Over time spans of several millennia, a preferred model for the age curves is not linear but may be exponential or parabolic, in which rates decrease with increasing age. These preliminary results imply that the geographical variation in rates within the southern Great Basin-Mojave region may be much less significant than temporal variation in rates of soil development. The reasons for temporal variation in rates and processes of soil development are complexly linked to climatic change and related changes in water and dust, erosional history, and internally driven chemical and physical processes.

Ten female Sprague-Dawley rats (45.3 days old, s.d. = 3.9) were acclimatised to running on a treadmill at 20 m/min on a 10 degrees incline for 1 hour per day. After mating, one rat from each of 5 pairs continued running on the treadmill at 15 m/min on a 10 degrees incline for 1 hour per day throughout gestation whilst the other rats followed normal laboratory routine. All the rats were weighed daily and at birth the number and weights of all fetuses were measured. In addition, a small piece of diaphragmatic muscle was taken from each of three fetuses from each litter and assessed both histologically and histochemically. The results showed that the maternal rats that did not continue exercising throughout pregnancy produced, on average, approximately 3 more fetuses per litter than the rats that exercised, although this difference was not significant. There was also no difference in mean fetal weight between the two groups and no difference could be demonstrated in the development of the diaphragm muscle.

Studies of the pedogenic iron oxyhydroxides in suites of latest Holocene to middle Pleistocene soils formed on fluvial deposits of the transverse ranges, southern California, indicate that the content and composition of iron oxyhydroxide change in a systematic manner. Analysis of total secondary free iron oxides (dithionite extractable, Fe 2O 3d) and ferrihydrite (oxalate extractable, Fe 2O 3o) shows that (1) a single-logarithmic model ( Y= a+ blog X) or double logarithmic model (log Y= a+ blog X), where Yis the total mass of pedogenic Fe oxides (g/cm 2-soil column) and Xis soil age, describes the rate of increase in Fe 2O 3d with time; (2) the Fe 2O 3d content correlates linearly with soil reddening and clay content; (3) the Fe2O 3o Fe2O 3dratio, which indicates the degree of Fe oxide crystallinity, is moderately high to very high (0.22–0.58) in middle Holocene to latest Pleistocene soils and progressively decreases to less than 0.10 in older soils; (4) the value of the Fe2O 3o Fe2O 3dratio also appears to be infuenced by climate; and (5) temporal changes in Fe oxide content and mineralogy are accompanied by related, systematic changes in clay mineralogy and organic matter content. These relationships are attributed to a soil environment that must initially favor ferrihydrite precipitation and/or organic matter-Fe complexation. Subsequent transformation to hematite causes increasingly intense reddening and a concomitant decrease in the Fe2O 3o Fe2O 3dratio. The results demonstrate that iron oxide analysis is useful for numerical age studies of noncalcic soils and shows potential as an indicator of paleoclimates.

Radiocarbon dating of late Quaternary deposits and shorelines of Lake Mojave and cation-ratio numerical age dating of stone pavements (Dorn, 1984)on the adjacent Soda Mountains piedmont provide age constraints for alluvial and eolian deposits. These deposits are associated with climatically controlled stands of Lake Mojave during the past 15,000 yr. Six alluvial fan units and three eolian stratigraphic units were assigned ages based on field relations with dated shorelines and piedmont surfaces, as well as on soil-geomorphic data. All but one of these stratigraphic units were deposited in response to time-transgressive climatic changes beginning approximately 10,000 yr ago. Increased eolian flux rates occurred in response to the lowering of Lake Mojave and a consequent increase in fine-sediment availability. Increased rates of deposition of eolian fines and associated salts influenced pedogenesis, stone-pavement development, and runoff-infiltration relations by (1) enhancing mechanical weathering of fan surfaces and hillslopes and (2) forming clay- and silt-rich surface horizons which decrease infiltration. Changes in alluvial-fan source areas from hillslopes to piedmonts during the Holocene reflect runoff reduction on hillslopes caused by colluvial mantle development and runoff enhancement on piedmonts caused by the development of less-permeable soils. Inferred increased in early to middle Holocene monsoonal activity resulted in high-magnitude paleo-sheetflood events on older fan pavements; this runoff triggered piedmont dissection which, in turn, caused increased sediment availability along channel walls. Thus, runoff-infiltration changes during the late Quaternary have occurred in response to eolian deposition of fines, pedogenesis, increased sheetflood activity in the Holocene, and vegetational changes which are related to many complicated linkages among climatic change, lake fluctuations, and eolian, hillslope, and alluvial-fan processes.

Numerical and calibrated age determinations of the late Quaternary alluvial fan deposits of the Soda Mountains piedmont in the Mojave Desert provide an opportunity to study the utility of the multiparameter relative-age (RA) method for distinguishing and mapping geomorphic surfaces on a desert piedmont. Most RA parameters could not discriminate between deposits of Holocene age, although pavements have formed over locally significant parts of surfaces as young as middle Holocene. Several parameters, including lithologic composition, particle size, soil development, and varnish cover, permit distinguishing between Holocene surfaces and late Pleistocene surfaces. Statistically significant differences in initial particle size and lithology of the deposits, inferred to be the result of complex interaction among hillslope, alluvial fan, and eolian processes and climatic change, create conditions unfavorable for use of most RA techniques. In contrast, soil-profile development and varnish cover data are successful in discrimination among deposits of Holocene and Pleistocene age. This is attributed to the development of pedogenic features and varnish that are strongly dependent on dust influx and to the relatively minor dependence of these features on differences in the depositional character of the fan.

Stratigraphic, sedimentologic, and pedologic studies of beach ridge and lacustrine deposits indicate that up to five times during the Holocene, shallow lakes covered Silver Lake playa in southeastern California for periods of years to decades. The two youngest lacustrine events (at about 390 ± 90 yr B. P. and 3620 ± 70 yr B. P.) coincide with the early and late Neoglacial episodes of North America. Increasing evidence in recent years from other nonglaciated areas leads us to conclude that the effects of these climatic episodes were much more widespread than previously thought. The climate during these episodes was characterized by an increased frequency of winter storms in the southwestern United States, causing wetter conditions that affected diverse, hyperarid environments in the Mojave Desert and adjacent regions. We propose that this wide areal coverage was caused by large-scale, winter atmospheric circulation patterns, which are probably related to changes in sea-surface temperatures and oceanic circulation in the eastern North Pacific Ocean.

A digital signal processing technique is proposed for calculating the amplitude and phase modulation of the tooth meshing vibration of a gear from the signal average of the vibration with application to the early detection of local defects such as fatigue cracks. The importance of phase modulation in the detection of defects is confirmed.

The application of the spectrogram to the calculation of the time-frequency distribution of a gear vibration signal is examined. The spectrogram represents the energy distribution of the signal over the frequency domain at every instant of time. The selection of the window function is discussed, and it is shown that the Gaussian function is well suited to the calculation of the energy distribution, giving a representation which is free from ripple and easy to interpret. The application of the energy distribution is demonstrated using numerically-generated test signals and the experimentally-measured time domain average of the gear meshing vibration from an industrial gearbox. The results suggest that the spectrogram may provide a powerful tool for the early detection of local gear damage. Copyright 1993, 1999 Academic Press