ZnO nanospheres were synthesised and then deposited by both single- and double-fire fast processes on as-prepared ceramic substrates. The photocatalytic degradation of resazurin ink was tested under ...UV light. The single-fired samples did not show any evidence of photocatalytic activity because the nanoparticles melted during sintering at 1210°C. The double-fire ZnO spray-coating method successfully produced glazed materials with an active ZnO surface layer despite the high sintering temperature. The influence of experimental parameters, including the ZnO nanoparticle loading (0.03 to 1 mg/cm2) and firing temperature (650 to 800°C), were also investigated. Samples with a ZnO loading of 1 g/cm2 fired at 650°C showed the best photocatalytic activity. Increasing the temperature to 700 and 800°C led to the coalescence of ZnO nanoparticles, which reduced the photocatalytic activity.
Purpose: To compare the reproducibility of two-dimensional (2D) peripapillary retinal nerve fiber layer (RNFL) thickness and threedimensional (3D) neuroretinal rim measurements using spectral domain ...optical coherence tomography (SDOCT) in normal and glaucoma subjects. Methods: One eye per subject for 27 normal and 40 glaucoma subjects underwent repeat SDOCT RNFL thickness scans and optic nerve volume scans on the same day. From the volume scan, custom software calculated five neuroretinal rim parameters: 3D minimum distance band (MDB) thickness, 3D MDB area, 3D rim volume, 2D rim area, and 2D rim thickness. Within-subject variance (Sw), coefficient of variation (CV), and intraclass correlation coefficient (ICC) were analyzed. Results: MDB thickness and RNFL thickness have similar reproducibility among normal and glaucoma subjects (eg, global MDB thickness CVs of 2.4% and 3.6%, and global RNFL thickness CVs of 1.3% and 2.2%; P > 0.05 for both comparisons). Reproducibility of MDB thickness was lower in glaucoma patients for the superior and inferior quadrants compared to normal subjects (CVs of 9.6% versus 3.4% and 6.9% versus 2.7%; P < 0.05, respectively). There were no statistically significant differences between both groups for RNFL thickness in the four quadrants. For both patient groups and for all regions, MDB thickness had the lowest CVs among all five neuroretinal rim parameters (eg, global MDB thickness CVs of 2.4% and 3.6% versus 3.0% and 18.9% for the other four neuroretinal rim parameters). Conclusion: Global MDB and global RNFL thickness are similarly reproducible among normal and glaucoma subjects, though MDB thickness for the superior and inferior quadrants is less reproducible among glaucoma subjects. Keywords: glaucoma, optical coherence tomography, reproducibility, optic nerve, minimum distance band
Students in schools of dentistry attend to patients with illnesses, and often prescribe medication. Because students are still learning, they are influenced by a variety of factors: the different ...teaching approaches of the professors at the clinics and in the pharmacology course, fellow students, and even the information provided by the pharmaceutical industry.
The aim of this pilot study was to assess the prescription knowledge and common mistakes in fourth-year students at the School of Dentistry at the Universidad Nacional Autónoma de México.
In March 2010, a survey was conducted among 66 fourth-year students at the School of Dentistry, applying a previously validated questionnaire consisting of six open-ended questions The following factors were assessed: the most frequent illness requiring dental prescription; the most prescribed nonsteroidal anti-inflammatory drugs and antibiotics; the most frequent errors; sources of information used for prescribing drugs; and whether the students knew and followed the World Health Organization Guide to Good Prescribing.
The most frequent response for each question was considered the most significant. The most common reason for prescribing medication was infection (n = 37, 56%), followed by pain (n = 24, 38%); the most used painkillers were ibuprofen and acetaminophen at equal levels (n = 25, 37.8%), followed by ketorolac (n = 7, 10.6%), naproxen (n = 6, 9.1%), diclofenac (n = 2, 3%), and aspirin (n = 1, 1.5%); the most widely prescribed antibiotics were amoxicillin (n = 52, 78.9%), ampicillin (n = 7, 10.6%), and penicillin V and clindamycin (n = 3, 4.5%). The most frequent errors reported by students were: lack of knowledge about drug posology (n = 49, 74.2%), improperly filled prescriptions (n = 7, 10.7%), not knowing the brand names and uncertainty about the correct drug indicated for each case (n = 3, 4.54%), not knowing the duration of treatment (n = 2, 3%), not asking the patient about possible allergies, and not giving prescriptions (n = 1, 1.5%). The sources of information used by students for prescribing drugs included the professors at the clinics (n = 49, 74.2%), the pharmacology course (n = 7, 10.7%), medical dictionary consultation (n = 15, 22.72%), classmate support (n = 3, 4.54%), and information provided by medical representatives from pharmaceutical companies (n = 1, 1.5%). Finally, only 20 students (30.3%) followed the WHO Guide to Good Prescribing, 40 students acknowledged not following it (60.6%), and six students (9.1%) had no knowledge of it.
The knowledge of pharmacology among fourth-year students in the School of Dentistry has gaps that could affect patient safety. More studies are needed to determine whether this issue affects the quality of patient care and the effectiveness and safety of treatments. Since prescribing accurately is extremely important, it is necessary to develop therapeutic guidelines, and to provide pharmacological therapy courses. The implementation of educational programs, including the WHO Guide to Good Prescribing and Patient Safety Curriculum Guide, would be beneficial in helping students develop prescribing skills.
Blood flow dynamics under physiologically realistic pulsatile conditions plays an important role in the growth, rupture, and surgical treatment of intracranial aneurysms. The temporal and spatial ...variations of wall pressure and wall shear stress in the aneurysm are hypothesized to be correlated with its continuous expansion and eventual rupture. In addition, the assessment of the velocity field in the aneurysm dome and neck is important for the correct placement of endovascular coils. This paper describes the flow dynamics in two representative models of a terminal aneurysm of the basilar artery under Newtonian and non-Newtonian fluid assumptions, and compares their hemodynamics with that of a healthy basilar artery. Virtual aneurysm models are investigated numerically, with geometric features defined by beta = 0 deg and beta = 23.2 deg, where beta is the tilt angle of the aneurysm dome with respect to the basilar artery. The intra-aneurysmal pulsatile flow shows complex ring vortex structures for beta = 0 deg and single recirculation regions for beta = 23.2 deg during both systole and diastole. The pressure and shear stress on the aneurysm wall exhibit large temporal and spatial variations for both models. When compared to a non-Newtonian fluid, the symmetric aneurysm model (beta = 0 deg) exhibits a more unstable Newtonian flow dynamics, although with a lower peak wall shear stress than the asymmetric model (beta = 23.2 deg). The non-Newtonian fluid assumption yields more stable flows than a Newtonian fluid, for the same inlet flow rate. Both fluid modeling assumptions, however, lead to asymmetric oscillatory flows inside the aneurysm dome.
In this work, we synthesized ZnO nanorods by a wet chemical process. By varying different parameters of the synthesis process like precursor concentration, solvent used, surfactant, temperature, and ...reaction time, we were able to control the aspect ratio (l/d) and sharpness factor (S f = h/b) of the rods. Rods with an aspect ratio of ∼20 and a sharpness factor of 10 were repeatedly obtained and characterized from scanning electron microscopy. High-resolution transmission electron microscopy and dark field analysis revealed that nanorods grow as a single crystal along the c axis 0001. UV and visible emission was obtained in both flat- and sharp-terminated rods. According to the XPS analysis, rods present an excess of Zn2+ of ∼4% that is responsible for the strong yellow emission band. Such defects were removed by annealing of the sample at 200 °C for 2 h. Possible mechanisms of changes in the morphology produced by changes in the synthesis process are also discussed.
Because S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) are the substrate and product of essential methyltransferase reactions; the ratio of SAM:SAH is frequently used as an indicator of ...cellular methylation potential. However, it is not clear from the ratio whether substrate insufficiency, product inhibition or both are required to negatively affect cellular methylation capacity. A combined genetic and dietary approach was used to modulate intracellular concentrations of SAM and SAH. Wild-type (WT) or heterozygous cystathionine β-synthase (CBS +/−) mice consumed a control or methyl-deficient diet for 24 wk. The independent and combined effect of genotype and diet on SAM, SAH and the SAM:SAH ratio were assessed in liver, kidney, brain and testes and were correlated with relative changes in tissue-specific global DNA methylation. The combined results from the different tissues indicated that a decrease in SAM alone was not sufficient to affect DNA methylation in this model, whereas an increase in SAH, either alone or associated with a decrease in SAM, was most consistently associated with DNA hypomethylation. A decrease in SAM:SAH ratio was predictive of reduced methylation capacity only when associated with an increase in SAH; a decrease in the SAM:SAH ratio due to SAM depletion alone was not sufficient to affect DNA methylation in this model. Plasma homocysteine levels were positively correlated with intracellular SAH levels in all tissues except kidney. These results support the possibility that plasma SAH concentrations may provide a sensitive biomarker for cellular methylation status.
We present molecular line observations of the high-mass molecular clump IRAS 16562−3959 taken at 3 mm using the Atacama Large Millimeter/submillimeter Array at 1 7 angular resolution (0.014 pc ...spatial resolution). This clump hosts the actively accreting high-mass young stellar object (HMYSO) G345.4938+01.4677, which is associated with a hypercompact H ii region. We identify and analyze emission lines from 22 molecular species (encompassing 34 isomers) and classify them into two groups, depending on their spatial distribution within the clump. One of these groups gathers shock tracers (e.g., SiO, SO, HNCO) and species formed in dust grains like methanol (CH3OH), ethenone or ketene (H2CCO), and acetaldehyde (CH3CHO). The second group collects species closely resembling the dust continuum emission morphology and are formed mainly in the gas phase, like hydrocarbons (CCH, c-C3H2, CH3CCH), cyanopolyynes (HC3N and HC5N), and cyanides (HCN and CH3C3N). Emission from complex organic molecules (COMs) like CH3OH, propanenitrile (CH3CH2CN), and methoxymethane (CH3OCH3) arise from gas in the vicinity of a hot molecular core (T 100 K) associated with the HMYSO. Other COMs such as propyne (CH3CCH), acrylonitrile (CH2CHCN), and acetaldehyde seem to better trace warm (T 80 K) dense gas. In addition, deuterated ammonia (NH2D) is detected mostly in the outskirts of IRAS 16562−3959 and associated with near-infrared dark globules, probably gaseous remnants of the clump's prestellar phase. The spatial distribution of molecules in IRAS 16562−3959 supports the view that in protostellar clumps, chemical tracers associated with different evolutionary stages-starless to hot cores/H ii regions-exist coevally.
Cuban DHF/DSS outbreaks have provided evidence of a reduced risk of people of Negroid race for DHF/DSS compared to those of Caucasoid race. These observations from Cuban dengue outbreaks have ...significant epidemiological interest, as the differences in susceptibility to DHF/DSS among racial groups in Cuba coincide with that reported in African and Black Caribbean populations. In this article, we review the literature on race as a risk factor for DHF/DSS and discuss recent results from onging studies. Taking into consideration the origins of contemporary Cuban inhabitants, we propose that the Cuban, Caribbean Black and African populations share a common gene pool that could explain, at least partially, the low incidence of dengue hemorrhagic fever in Cuba and Caribbean and African countries. The central role played by immunological mechanisms in the pathogenesis of DHF/DSS has led us to consider that the polymorphic genes associated with the immune response must be carefully considered among those human genes regulating dengue disease severity that might be distributed unequally in Blacks and Whites.
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