Nowadays, the use of self-cleaning surfaces is increasing globally, especially after the COVID-2019 pandemic, and the use of nanoparticles has been shown as a plausible option for this purpose. In ...the present study, Cu-doped SnO2 nanocrystals were successfully synthesized (in the copper content range of 0–30 mol%) using the polymeric precursor method. The structural, morphological, vibrational, and antibacterial activity were carefully studied to unveil the effect of copper ions on the properties of the hosting matrix, aiming at maximizing the usage of Cu-doped SnO2 nanocrystals. The results show fabrication of nanoparticles near their respective exciton Bohr diameter (5.4 nm for SnO2), however, monophasic SnO2 was observed up to 15 mol%. Above this limit, a secondary CuO phase was observed, as shown by the assessed X-ray diffraction (XRD), Fourier transform infrared, and Raman spectroscopy data. Furthermore, the redshift of the primary A1g vibrational mode of SnO2 is successfully described using the phonon-confinement model, demonstrating a good relationship between the Raman correlation length (L) and the crystallite size (⟨D⟩), the latter determined from XRD. Regarding the antibacterial activity, assessed via the disc-diffusion testing method (DDTM) while challenging two bacterial species (S. aureus and E. coli), our results suggest a rapid diffusion of the nanoparticles out of the paper disc, with a synergistic effect credited to the Sn1−xCuxO2–CuO phases contributing to the inhibition of the bacteria growth. Moreover, the DDTM data scales with cell viability, the latter analyzed using the Hill equation, from which both lethal dose 50 (LD50) and benchmark dose (BMD) were extracted.
Background. Trichomoniasis is a sexually transmitted infection that mainly affects women. The diagnosis is made by different methods that identify the presence of Trichomonas vaginalis; therefore, ...sensitivity, specificity, and performance are essential to guarantee an adequate diagnosis. Our study is aimed at comparing three methods for diagnosing trichomoniasis in patients treated at a hospital in Peru during the year 2018. Methods. We designed a cross-sectional study and enrolled women whose vaginal secretion samples were evaluated by direct examination, Papanicolaou staining, and culture in the Diamond medium. Results. We evaluated 134 women with a mean age of 36.6±12.1 years and a beginning of sexual activity of 18.5±3.0 years. We found leukocyte infiltration, fetid odor, and strawberry cervix in 66.4%, 35.1%, and 18.7%. The prevalence of trichomoniasis by the culture method, direct examination, and Papanicolaou was 32.1, 21.6, and 11.2%. The direct examination’s sensitivity, specificity, and diagnostic performance (AUC) were 65.1%, 98.9%, and 82.0%, while for the Pap smear, they were 32.6%, 98.9%, and 65.7%%. Conclusion. The culture of T. vaginalis is the gold standard for diagnosing trichomoniasis; however, direct examination is a fast, specific alternative with good diagnostic performance. The Pap test has low sensitivity and should not be used in settings where the prevalence and risk factors for trichomoniasis are high.
Nowadays, the use of self-cleaning surfaces is increasing globally, especially after the COVID-2019 pandemic, and the use of nanoparticles has been shown as a plausible option for this purpose. In ...the present study, Cu-doped SnO 2 nanocrystals were successfully synthesized (in the copper content range of 0–30 mol%) using the polymeric precursor method. The structural, morphological, vibrational, and antibacterial activity were carefully studied to unveil the effect of copper ions on the properties of the hosting matrix, aiming at maximizing the usage of Cu-doped SnO 2 nanocrystals. The results show fabrication of nanoparticles near their respective exciton Bohr diameter (5.4 nm for SnO 2 ), however, monophasic SnO 2 was observed up to 15 mol%. Above this limit, a secondary CuO phase was observed, as shown by the assessed X-ray diffraction (XRD), Fourier transform infrared, and Raman spectroscopy data. Furthermore, the redshift of the primary A 1g vibrational mode of SnO 2 is successfully described using the phonon-confinement model, demonstrating a good relationship between the Raman correlation length ( L ) and the crystallite size (〈 D 〉), the latter determined from XRD. Regarding the antibacterial activity, assessed via the disc-diffusion testing method (DDTM) while challenging two bacterial species ( S. aureus and E. coli ), our results suggest a rapid diffusion of the nanoparticles out of the paper disc, with a synergistic effect credited to the Sn 1− x Cu x O 2 –CuO phases contributing to the inhibition of the bacteria growth. Moreover, the DDTM data scales with cell viability, the latter analyzed using the Hill equation, from which both lethal dose 50 (LD50) and benchmark dose (BMD) were extracted.
Nowadays, the use of self-cleaning surfaces is increasing globally, especially after the COVID-2019 pandemic, and the use of nanoparticles has been shown as a plausible option for this purpose. In ...the present study, Cu-doped SnO
2
nanocrystals were successfully synthesized (in the copper content range of 0-30 mol%) using the polymeric precursor method. The structural, morphological, vibrational, and antibacterial activity were carefully studied to unveil the effect of copper ions on the properties of the hosting matrix, aiming at maximizing the usage of Cu-doped SnO
2
nanocrystals. The results show fabrication of nanoparticles near their respective exciton Bohr diameter (5.4 nm for SnO
2
), however, monophasic SnO
2
was observed up to 15 mol%. Above this limit, a secondary CuO phase was observed, as shown by the assessed X-ray diffraction (XRD), Fourier transform infrared, and Raman spectroscopy data. Furthermore, the redshift of the primary A
1g
vibrational mode of SnO
2
is successfully described using the phonon-confinement model, demonstrating a good relationship between the Raman correlation length (
L
) and the crystallite size (〈
D
〉), the latter determined from XRD. Regarding the antibacterial activity, assessed
via
the disc-diffusion testing method (DDTM) while challenging two bacterial species (
S. aureus
and
E. coli
), our results suggest a rapid diffusion of the nanoparticles out of the paper disc, with a synergistic effect credited to the Sn
1−
x
Cu
x
O
2
-CuO phases contributing to the inhibition of the bacteria growth. Moreover, the DDTM data scales with cell viability, the latter analyzed using the Hill equation, from which both lethal dose 50 (LD50) and benchmark dose (BMD) were extracted.
Tuning the physical properties of Cu-doped SnO
2
NPs to potential use as self-cleaning surfaces.
We analyze the performance of an Omnivision OV5647 CMOS image sensor (5 Mp) for measuring the radiation emitted from Sr90 and Cs137 sources. Our experimental arrangement includes a Raspberry Pi 3 ...mini-computer for data taking, processed with Python and OpenCV libraries. We specify the camera settings to be sensitive to detecting electrons and photons. We also implement a detailed Geant4 simulation of the CMOS sensor and the radioactive sources. This simulation connects the deposited energy in the pixel matrix by the electrons and photons from the radioactive sources and the ADC counts. Our measurements are expressed through the cluster size, the maximum ADC signal per cluster, and the variation of the clusters with different distances. We find a good agreement between the data and the Geant4 simulation for all these observables. Furthermore, we can reproduce the correlation between the cluster size and the maximum ADC per cluster.
We have designed and tested an automated simple setup for quickly measuring the profile and spot size of a Gaussian laser beam using three cost-affordable light sensors. Two profiling techniques were ...implemented: imaging for the CMOS 2D array (webcam) and scanning knife-edge-like using a single photodiode and an LDR. The methods and sensors were compared to determine their accuracy using lasers of two different wavelengths and technologies. We verify that it is possible to use a low-cost webcam to determine the profile of a laser with 1% uncertainty on the beam waist, 1.5% error on the waistline position, and less than 3% error in determining the minimum spot radius. The photodiode measurement is the most stable since it is not affected by the change in laser intensity. In addition, we show that it is possible to use an inexpensive LDR sensor to estimate the laser spot size with an 11% error.
Presenta el diseño de una experiencia piloto de pago por servicios ambientales por parte de los demandantes del recurso hidiroc hacia los oferentes del mismo, de tal fomra que se puedan generar ...actividades productivas sostenibles a favor de la conservacion de los ecosistemas naturales y de los servicios ambientales que esta provee. Tambien presenta el esquema del pago por Servicios Ambientales, haciendo una exposicion de su arreglo institucional, asi como sugiriendo alternativas de utilizacion para los probables ingresos que se puedan percibir a partir de un esquema de priorizacion que llevaria a un mejor uso de los fondos obtenidos.
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