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1.
J Shoulder Elbow Surg ; 29(6): 1104-1114, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32044253

RESUMO

BACKGROUND: Improved short-term outcomes have been demonstrated with higher surgical volume in shoulder arthroplasty. There is however, little data regarding long-term outcomes. METHOD: Revision data from the Australian Orthopaedic Association National Joint Replacement Registry from 2004-2017 was analyzed according to 3 selected surgeon volume thresholds: <10, 10-20, and >20 shoulder arthroplasty cases per surgeon, per year. RESULTS: There was a significantly higher rate of revision for stemmed total shoulder arthroplasty (TSA) for osteoarthritis (OA) for the <10/yr compared with the >20/yr group for the first 1.5 years only (hazard ratio [HR] 1.36, 95% confidence interval [CI] 1.08-1.71, P = .009). For reverse total shoulder arthroplasty (rTSA) performed for OA, there was a higher revision rate for the <10/yr compared with the >20/yr group for the first 3 months only (HR 2.58, 95% CI 1.67-3.97, P < .001). In rTSA for cuff arthropathy, there was a significantly higher rate of revision for the <10/yr compared with the >20/yr group throughout the follow-up period (HR 1.66, 95% CI 1.21-2.28, P = .001). There was no significant difference for the primary diagnosis of fracture. CONCLUSION: Lower surgical volume was associated with higher all-cause revision rates in the early postoperative period in TSA and rTSA for OA and throughout the follow-up period in rTSA for cuff arthropathy. Despite increases in the volume of shoulder arthroplasties performed in recent years, more than 78% of surgeons undertake fewer than 10 procedures per year.


Assuntos
Artroplastia do Ombro/efeitos adversos , Artroplastia do Ombro/estatística & dados numéricos , Osteoartrite/cirurgia , Complicações Pós-Operatórias/epidemiologia , Artropatia de Ruptura do Manguito Rotador/cirurgia , Idoso , Austrália , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/cirurgia , Utilização de Procedimentos e Técnicas , Sistema de Registros , Reoperação , Estudos Retrospectivos , Resultado do Tratamento
2.
Glob Chang Biol ; 22(3): 1244-55, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26491961

RESUMO

Perennial crops can deliver a wide range of ecosystem services compared to annual crops. Some of these benefits are achieved by lengthening the growing season, which increases the period of crop water and nutrient uptake, pointing to a potential role for perennial systems to mitigate soil nitrous oxide (N2 O) emissions. Employing a micrometeorological method, we tested this hypothesis in a 3-year field experiment with a perennial grass-legume mixture and an annual corn monoculture. Given that N2 O emissions are strongly dependent on the method of fertilizer application, two manure application options commonly used by farmers for each crop were studied: injection vs. broadcast application for the perennial; fall vs. spring application for the annual. Across the 3 years, lower N2 O emissions (P < 0.001) were measured for the perennial compared to the annual crop, even though annual N2 O emissions increased tenfold for the perennial after ploughing. The percentage of N2 O lost per unit of fertilizer applied was 3.7, 3.1 and 1.3 times higher for the annual for each consecutive year. Differences in soil organic matter due to the contrasting root systems of these crops are probably a major factor behind the N2 O reduction. We found that a specific manure management practice can lead to increases or reductions in annual N2 O emissions depending on environmental variables. The number of freeze-thaw cycles during winter and the amount of rainfall after fertilization in spring were key factors. Therefore, general manure management recommendations should be avoided because interannual weather variability has the potential to determine if a specific practice is beneficial or detrimental. The lower N2 O emissions of perennial crops deserve further research attention and must be considered in future land-use decisions. Increasing the proportion of perennial crops in agricultural landscapes may provide an overlooked opportunity to regulate N2 O emissions.


Assuntos
Agricultura/métodos , Poluentes Atmosféricos/análise , Produtos Agrícolas/metabolismo , Monitoramento Ambiental , Fertilizantes/análise , Óxido Nitroso/análise , Clima , Fabaceae/metabolismo , Esterco , Óxido Nitroso/metabolismo , Ontário , Poaceae/metabolismo , Estações do Ano , Solo/química , Zea mays/metabolismo
3.
J Environ Qual ; 45(6): 2038-2043, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27898776

RESUMO

When liquid manure is removed from storages for land application, "sludge" generally remains at the bottom of the tank. This may serve as an inoculum when fresh manure is subsequently added, thereby increasing methane (CH) emissions. Previous pilot-scale studies have shown that completely emptying storages can decrease CH emissions; however, no farm-scale studies have been conducted to quantify the effect of sludge removal. In this study, a commercial dairy farm removed as much manure and sludge from their concrete storage as possible in the fall (∼2% by volume remained). Emissions of CH were measured during the following winter, spring, and summer, and compared with emissions measured the preceding 2 yr when most of the sludge had not been removed (∼14% of tank volume remained). Emissions were measured using a micrometeorological technique, utilizing open-path CH lasers. Contrary to what was hypothesized, removing the majority of sludge in fall did not delay the onset of CH emissions and did not decrease emissions the following summer. In fact, annual CH emissions were ∼16% higher. It is possible that fall removal provided sufficient time for microbial dynamics to be restored before the following summer when emissions were high. Future farm-scale research should examine the effect of spring (rather than fall) emptying for on-farm CH mitigation in both concrete tanks and earthen storages.


Assuntos
Esterco , Metano/análise , Dióxido de Carbono , Indústria de Laticínios , Óxido Nitroso , Esgotos
4.
J Environ Qual ; 45(6): 1822-1828, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27898800

RESUMO

A significant need exists to improve our understanding of the extent of greenhouse gas emissions from the storage of livestock manure to both improve the reliability of inventory assessments and the impact of beneficial management practice adoption. Factors affecting the extent and variability of greenhouse gas emissions from stored dairy manure were investigated. Emissions from six slurries stored in clean concrete tanks under identical "warm-season" conditions were monitored consecutively over 173 d (18°C average air temperature). Methane (CH) emissions varied considerably among the manures from 6.3 to 25.9 g m d and accounted for ∼96% of the total CO equivalent greenhouse gas emissions. The duration of the lag period, when methane emissions were near baseline levels, varied from 30 to 90 d from the beginning of storage. As a result, CH emissions were poorly correlated with air temperature prior to the time of peak emissions (i.e., the initial 48 to 108 d of storage) but improved afterward. The air temperature following the time of the peak CH flux and the length of the active methanogenesis period (i.e., when the daily CH emissions ≥ 7.6 g m d) were highly correlated with CH emissions ( = 0.98, < 0.01). Methane conversion factors (MCFs) ranged from 0.08 to 0.52 for the different manures. The MCFs generated from existing CH emission models were correlated ( = 0.68, = 0.02) to MCFs calculated for the active methanogenesis period for manure containing wood bedding. A temperature component was added that improved the accuracy ( = 0.82, < 0.01). This demonstrated that an improved understanding of lag period dynamics will enhance stored dairy manure greenhouse gas emission inventory calculations.


Assuntos
Indústria de Laticínios , Gases de Efeito Estufa/análise , Esterco , Fazendas , Metano , Eliminação de Resíduos , Reprodutibilidade dos Testes
5.
J Peripher Nerv Syst ; 20(4): 363-71, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26313450

RESUMO

We examined the efficacy and safety of ranirestat in patients with diabetic sensorimotor polyneuropathy (DSPN). Patients (18-75 years) with stable type 1/2 diabetes mellitus and DSPN were eligible for this global, double-blind, phase II/III study (ClinicalTrials.gov NCT00927914). Patients (n = 800) were randomized 1 : 1 : 1 to placebo, ranirestat 40 mg/day or 80 mg/day (265 : 264 : 271). Change in peroneal motor nerve conduction velocity (PMNCV) from baseline to 24 months was the primary endpoint with a goal improvement vs. placebo ≥1.2 m/s. Other endpoints included symptoms, quality-of-life, and safety. Six hundred thirty-three patients completed the study. The PMNCV difference from placebo was significant at 6, 12, and 18 months in both ranirestat groups, but <1.2 m/s. The mean improvement from baseline at 24 months was +0.49, +0.95, and +0.90 m/s for placebo, ranirestat 40 mg and 80 mg, respectively (NS). The treatment difference vs. placebo reached significance when ranirestat groups were combined in a post hoc analysis (+0.44 m/s; p = 0.0237). There was no effect of ranirestat on safety assessments, secondary or exploratory endpoints vs. placebo. Ranirestat was well tolerated and improved PMNCV, but did not achieve any efficacy endpoints. The absence of PMNCV worsening in the placebo group underscores the challenges of DSPN studies in patients with well-controlled diabetes.


Assuntos
Neuropatias Diabéticas/tratamento farmacológico , Polineuropatias/tratamento farmacológico , Pirazinas/uso terapêutico , Compostos de Espiro/uso terapêutico , Idoso , Neuropatias Diabéticas/fisiopatologia , Progressão da Doença , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Condução Nervosa/efeitos dos fármacos , Condução Nervosa/fisiologia , Polineuropatias/fisiopatologia , Pirazinas/efeitos adversos , Pirazinas/farmacologia , Qualidade de Vida , Compostos de Espiro/efeitos adversos , Compostos de Espiro/farmacologia , Resultado do Tratamento
6.
J Chem Phys ; 142(14): 144311, 2015 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-25877582

RESUMO

Shaped ultrafast laser pulses were used to study and control the ionization dynamics of electronically excited pyrazine in a pump and probe experiment. For pump pulses created without feedback from the product signal, the ion growth curve (the parent ion signal as a function of pump/probe delay) was described quantitatively by the classical rate equations for internal conversion of the S2 and S1 states. Very different, non-classical behavior was observed when a genetic algorithm (GA) employing phase-only modulation was used to minimize the ion signal at some pre-determined target time, T. Two qualitatively different control mechanisms were identified for early (T < 1.5 ps) and late (T > 1.5 ps) target times. In the former case, the ion signal was largely suppressed for t < T, while for t ≫ T, the ion signal produced by the GA-optimized pulse and a transform limited (TL) pulse coalesced. In contrast, for T > 1.5 ps, the ion growth curve followed the classical rate equations for t < T, while for t ≫ T, the quantum yield for the GA-optimized pulse was much smaller than for a TL pulse. We interpret the first type of behavior as an indication that the wave packet produced by the pump laser is localized in a region of the S2 potential energy surface where the vertical ionization energy exceeds the probe photon energy, whereas the second type of behavior may be described by a reduced absorption cross section for S0 → S2 followed by incoherent decay of the excited molecules. Amplitude modulation observed in the spectrum of the shaped pulse may have contributed to the control mechanism, although this possibility is mitigated by the very small focal volume of the probe laser.

7.
J Environ Qual ; 44(6): 1965-73, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26641349

RESUMO

A 2-yr study compared the performance of seasonally and continuously loaded constructed wetlands treating dairy farm wastewater. One wetland was loaded during the growing season (GS) periods only, while the other was continuously loaded. Weekly samples were analyzed for 5-d biochemical oxygen demand (BOD), total suspended solids (TSS), total Kjeldahl N (TKN), total ammoniacal N (TAN), total P (TP), and . Annual average daily mass removal rates (kg ha) were similar for both wetlands in both years; however, seasonal differences were observed. With the exception of BOD in Year 2, average daily GS areal mass removal rates were higher for the seasonal wetland. However, GS mass exports from the seasonal wetland were higher by 28 to 94%, with the exception of BOD in Year 1. Annual mass reductions (MRs; %) for nutrients were higher for the continuous wetland in both years. Annual MRs were similar for in both years and for TSS in Year 2. Annual mass exports from the seasonal wetland were higher for nutrients and by 14 to 77% in both years. Pollutant MRs generally decreased during the nongrowing season (NGS) for the continuous wetland; however, in Year 2 when lower loading rates were used, the wetland still removed 84 to 99% of the pollutant masses. The continuous wetland also performed better during periods of high flow that occurred during the GS. Although there were minimal differences in annual treatment performance, continuously loaded systems require less additional infrastructure and should require less maintenance and may, therefore, be more attractive for agricultural applications.

8.
J Environ Qual ; 43(4): 1356-69, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25603083

RESUMO

Phosphorus (P) loading from residential onsite wastewater systems (OWSs) into neighboring surface waters is a poorly understood process in rural watersheds; this can be further challenged when rural residential dwellings are intermixed with agricultural land use. The objectives of this research were (i) to design a P onsite wastewater simulator (POWSIM) to assess P loads from individual or clusters of residential OWSs typically used in Nova Scotia, Canada; and (ii) to simulate OWS P loads in a mixed agricultural watershed (Thomas Brook Watershed [TBW], NS) using the Soil and Water Assessment Tool (SWAT) model in conjunction with POWSIM, to predict and compare P loading from agricultural and residential sources. The POWSIM loading tool has three computational components: (i) disposal field selection and treatment media mass calculation, (ii) disposal field P treatment dynamics, and (iii) soil subsurface plume P treatment dynamics. The combination TBW POWSIM and SWAT modeling approach produced a better simulation of baseflow total P (TP) loads in both a predominantly residential subcatchment and one dominated by agriculture than the SWAT model without POWSIM. The residential subcatchment had 48% of its average annual land use TP load (simulated) contributed by OWSs, whereas the agricultural subcatchment had 39%. Watershed-scale sensitivity analyses of POWSIM input parameters for 18- and 50-yr OWS operation periods found the P loading rate into the disposal field, long-term P removal rates in the disposal field and soil systems, soil maximum P sorption capacity, and mass of native soil involved in P treatment to be most sensitive.

9.
Anal Chem ; 84(9): 3945-51, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22482364

RESUMO

Experiments were performed to examine the feasibility of mass spectrometry (MS) depth profiling of animal tissue by ~75 fs, 800 nm laser pulses to expose underlying layers of tissue for subsequent MS analysis. Matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) was used to analyze phospholipids and proteins from both intact bovine eye lens tissue and tissue ablated by ultrashort laser pulses. Laser desorption postionization mass spectrometry (LDPI-MS) with 10.5 eV single photon ionization was also used to analyze cholesterol and other small molecules in the tissue before and after laser ablation. Scanning electron microscopy was applied to examine the ablation patterns in the tissue and estimate the depth of the ablation craters. Ultrashort pulse laser ablation was found to be able to remove a layer of several tens of micrometers from the surface of eye lens tissue while leaving the underlying tissue relatively undamaged for subsequent MS analysis. MS analysis of cholesterol, phospholipids, peptides, and various unidentified species did not reveal any chemical damage caused by ultrashort pulse laser ablation for analytes smaller than ~6 kDa. However, a drop in intensity of larger protein ions was detected by MALDI-MS following laser ablation. An additional advantage was that ablated tissue displayed up to an order of magnitude higher signal intensities than intact tissue when subsequently analyzed by MS. These results support the use of ultrashort pulse laser ablation in combination with MS analysis to permit depth profiling of animal tissue.


Assuntos
Proteínas do Olho/análise , Terapia a Laser , Cristalino/química , Espectrometria de Massas/métodos , Fosfolipídeos/análise , Animais , Bovinos , Lasers , Cristalino/ultraestrutura , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos
10.
Phys Rev Lett ; 109(7): 073002, 2012 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-23006365

RESUMO

We demonstrate strong coupling between molecular excited states and surface plasmon modes of a slit array in a thin metal film. The coupling manifests itself as an anticrossing behavior of the two newly formed polaritons. As the coupling strength grows, a new mode emerges, which is attributed to long-range molecular interactions mediated by the plasmonic field. The new, molecular-like mode repels the polariton states, and leads to an opening of energy gaps both below and above the asymptotic free molecule energy.

11.
J Phys Chem A ; 115(23): 6093-101, 2011 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-21338157

RESUMO

A genetic algorithm was used to control the photoluminesce-nce (PL) from GaAs(100). A spatial light modulator (SLM) used feedback from the emission to optimize the spectral phase profile of an ultrashort laser pulse. Most of the experiments were performed using a sine phase function to optimize the integrated PL spectrum over a specified wavelength range, with the amplitude and period of the phase function treated as genetic parameters. An order of magnitude increase in signal was achieved after only one generation, and an optimized waveform, consisting of three equally spaced pulses approximately 0.8 ps apart, was obtained after 15 generations. The effects of fluence, polarization, relative phase of the subpulses, and spectral range of the optimized PL were investigated. In addition, preliminary experiments were performed using the phases of individual pixels of the SLM as genetic variables. The PL spectrum is identified with recombination of electron-hole pairs in the L-valley of the Brillouin zone. Control is achieved by coherent manipulation of plasma electrons. It is proposed that hot electrons excite lattice phonons, which in turn scatter carriers into the L-valley.

12.
Sci Total Environ ; 750: 142278, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182183

RESUMO

This study explores the variation of liquid manure temperature (Tm) and CH4 emissions associated with contrasting regional climates, inter-annual weather variation, and manure storage emptying. As a case-study, six regions across Canada were used, spanning 11°32' latitude and 58°30' longitude. Annual average air temperatures ranged from 3.9 °C (prairie climate) to 10.5 °C (maritime climate), with an overall average of 6.6 °C. A model predicted Tm over 30 years, using daily weather (1971-2000), and over one "normal" year (30-year average weather). Modelled Tm was then used in Manure-DNDC to model daily CH4 emissions. Two manure storage emptying scenarios were simulated: (i) early spring and autumn, or (ii) late spring and autumn. Regional differences were evident as average Tm ranged from 8.9 °C to 14.6 °C across the six locations. Early removal of stored manure led to warmer Tm in all regions, and the most warming occurred in colder regions. Regional climate had a large effect on CH4 emissions (e.g. 1.8× greater in the pacific maritime and great lakes regions than the prairie region). Inter-annual weather variability led to substantial variation in inter-annual CH4 emissions, with coefficient of variation being as high as 20%. The large inter-annual range suggests that field measurements of CH4 emissions need to compare the weather during measurements to historical normals. Early manure storage emptying reduced CH4 emissions (vs late removal) in some regions but had little effect or the opposite effect in other regions. Overall, the results from this modelling study suggest: i) Tm differs substantially from air temperature at all locations, ii) accurate estimates of manure storage CH4 emissions require region-specific calculations using Tm (e.g. in emission inventories), iii) field measurements of CH4 emissions need to consider weather conditions relative to climate normal, and iv) emission mitigation practices will require region-specific measurements to determine impacts.

13.
Opt Lett ; 35(2): 112-4, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20081938

RESUMO

It is shown that the continuum emission produced in the ablation of an Al target with nanosecond laser pulses is much more strongly polarized than the discrete line emission. This effect may be utilized to improve the resolution of the laser-induced breakdown spectroscopy spectrum by using a polarizer to filter out the continuum background. The effects of laser fluence and focal position are also reported. It is further shown that the lifetime of the emission closely tracks the intensity spectrum.

14.
J Vac Sci Technol A ; 28(4): 647-651, 2010 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-21031139

RESUMO

Sample ablation by pulsed lasers is one option for removing material from a sample surface for in situ depth profiling during imaging mass spectrometry, but ablation is often limited by laser-induced damage of the remaining material. A preliminary evaluation was performed of sub-100 fs, 800 nm pulsed laser ablation for depth profiling of bacterial biofilms grown on glass by the drip flow method. Electron and optical microscopy were combined with laser desorption vacuum ultraviolet postionization mass spectrometry to analyze biofilms before and after ablation. Ultrashort laser pulses can ablate 10 - 100 µm thick sections of bacterial biofilms, leaving behind a layer of lysed cells. However, mass spectra from intact and ablated biofilms doped with antibiotic are almost identical, indicating little chemical degradation by ablation. These results are consistent with prior observations from laser surgery and support the use of ultrashort pulse laser ablation for minimally disruptive depth profiling of bacterial biofilms and intact biological samples.

15.
Phys Rev Lett ; 103(17): 173903, 2009 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-19905759

RESUMO

Efficient energy transfer between two ultrafast laser beams is reported. Energy transfer occurs when linearly polarized donor and acceptor beams are focused in air and intersect at an acute angle. This effect is attributed to plasma-mediated forward stimulated Raman scattering, facilitated by supercontinuum generation. Donor depletion as high as 57% is observed, with quantitative energy transfer from the donor to the acceptor beam. Amplification of the acceptor depends on the polarization directions of the two pulses and the delay between them. Interaction between the beams results also in compression and spectral broadening of the acceptor pulse.

16.
J Phys Chem A ; 113(47): 13310-7, 2009 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-19658415

RESUMO

It is shown that the continuous background of the laser-induced breakdown spectrum of Al produced by 800 nm femtosecond pulses is strongly polarized. Use of a polarizer to filter out the background significantly improves the signal/noise and signal/background ratios of the discrete line spectrum. The effects of the laser pulse energy, focal position, incidence and detection angles, and the polarization plane of the laser were investigated. Polarization resolved laser-induced breakdown spectroscopy (PRLIBS) is much less sensitive to these variables than conventional, ungated fs-LIBS, making this a much more versatile analytical tool. These measurements reveal qualitatively different mechanisms for the continuous and discrete parts of the spectrum.

17.
J Air Waste Manag Assoc ; 69(9): 1096-1106, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31184562

RESUMO

Liquid manure storages are a significant source of methane (CH4) emissions. Farmers commonly agitate (stir) liquid manure prior to field application to homogenize nutrients and solids. During agitation, manure undergoes mechanical stress and is exposed to the air, disrupting anaerobic conditions. This on-farm study aimed to better understand the effects of agitation on CH4 emissions, and explore the potential for intentional agitation (three times) to disrupt the exponential increase of CH4 emissions in spring and summer. Results showed that agitation substantially increased manure temperature in the study year compared to the previous year, particularly at upper- and mid-depths of the stored manure. The temporal pattern of CH4 emissions was altered by reduced emissions over the subsequent week, followed by an increase during the second week. Microbial analysis indicated that the activity of archaea and methanogens increased after each agitation event, but there was little change in the populations of methanogens, archaea, and bacteria. Overall, CH4 emissions were higher than any of the previous three years, likely due to warmer manure temperatures that were higher than the previous years (despite similar air temperatures). Therefore, intermittent manure agitation with the frequency, duration, and intensity used in this study is not recommended as a CH4 emission mitigation practice. Implications: The potential to mitigate methane emissions from liquid manure storages by strategically timed agitation was evaluated in a detailed farm-scale study. Agitation was conducted with readily-available farm equipment, and targeted at the early summer to disrupt methanogenic communities when CH4 emissions increase exponentially. Methane emissions were reduced for about one week after agitation. However, agitation led to increased manure temperature, and was associated with increased activity of methanogens. Overall, agitation was associated with similar or higher methane emissions. Therefore, agitation is not recommended as a mitigation strategy.


Assuntos
Esterco/análise , Metano/análise , Temperatura , Fenômenos Fisiológicos Bacterianos , Fazendas , Fertilizantes/análise
18.
J Chem Phys ; 129(24): 244301, 2008 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-19123501

RESUMO

The electric field of a light wave accumulates a pi phase shift as it passes through a focus. We show here how this effect, known as the Gouy phase, may be used to control the branching ratio of a unimolecular reaction when the products are formed with different numbers of photons. We demonstrate this control method for the ionization and dissociation of vinyl chloride, using absorption of 177 and 532 nm photons to induce a pair of interfering paths. Excellent agreement between the observed and calculated phase shift as a function of the axial coordinate of the laser focus indicates that fragmentation occurs via a ladder switching mechanism. The axial dependence of the modulation depth is evidence of loss of coherence at higher internal temperatures of the molecule.

19.
Ophthalmic Surg Lasers Imaging ; 39(6): 485-90, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19065979

RESUMO

BACKGROUND AND OBJECTIVE: The femtosecond laser is a promising tool for the micromachining of biological tissues. The current study investigated the feasibility of noninvasive glaucoma therapy by femtosecond laser ablation in enucleated porcine eyes by delivering the laser energy through a gonioscopic lens. MATERIALS AND METHODS: Freshly enucleated porcine eyes were kept in Optisol GS solution (Bausch & Lomb, Rochester, NY) at 4 degrees C for up to 48 hours. Photodisruption was attempted at the peripheral inner surface of the cornea using a gonioscopic lens and a custom femtosecond laser ablation system. Femtosecond laser ablation was performed using a Ti:Sapphire laser (800-nm wavelength) focused with a 0.15 numerical aperture lens. The laser treatment process was recorded by real time video and the lesions were examined histologically. RESULTS: During laser surgery, bubble formation was observed and appeared to be positively related to laser energy and exposure time. When examined histologically, areas of ablation were consistently observed at the peripheral inner surface of the cornea. The extent of the lesion increased nonlinearly with both pulse energy and exposure time, showing saturation at high energy and long times. For a given energy dose, fewer pulses of high energy were more effective than many low energy pulses. CONCLUSION: The current study demonstrates that laser ablation at the anterior chamber angle is feasible by a femtosecond laser ablation system using a gonioscopic lens in ex vivo eyes. The results indicate the potential of a novel noninvasive glaucoma laser therapy.


Assuntos
Câmara Anterior/cirurgia , Glaucoma/cirurgia , Animais , Enucleação Ocular , Estudos de Viabilidade , Gonioscopia , Terapia a Laser , Lasers Semicondutores , Suínos , Malha Trabecular/cirurgia , Trabeculectomia/métodos
20.
Environ Technol ; 39(7): 851-858, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28355494

RESUMO

The effect of two dairy manure treatments, solid-liquid separation (SLS) and anaerobic digestion (AD), on methane potential and the speed of production was evaluated. Assays were performed in the lab to measure methane (CH4) production over 202 d from dairy manure samples taken before and after each treatment. Compared to raw manure, CH4 emissions on a per-L basis were reduced 81% by SLS and 59% by AD, on average. The mean (SD) ultimate CH4 emission potential (B0) per kg of volatile solids (VS) was 247 (8) L CH4 kg-1 VS for raw manure, 221 (9) L CH4 kg-1 VS for separated liquid, and 160 (4) L CH4 kg-1 VS for anaerobic digestate. Thus, SLS reduced the B0 of the liquid fraction by 11% and AD reduced B0 by up to 35% compared to raw manure. Manure treatment affected the speed of CH4 production: SLS increased the CH4 production rate and thus separated liquid manure was the fastest to produce 90% of the ultimate CH4 production. Therefore, both the speed of degradation and B0 should be considered when assessing these techniques for farm-scale manure storages, because actual emission reductions will depend on storage conditions.


Assuntos
Esterco , Metano/análise , Gerenciamento de Resíduos , Anaerobiose , Fazendas
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