A facile bottom–up “green” synthetic route using green tea (
Camellia sinensis) extract as reducing and stabilizing agent produced gold nanoparticles and silver nanostructures in aqueous solution at ...ambient conditions. Colloidal systems of silver and gold nanoparticles exhibit highly efficient single photon-induced luminescence. This optical response can be manipulated by changing concentrations of metal ions and the quantity of reducing agent, which plays a crucial role in formation, growth and luminescence response of these noble-metal nanostructures.
•Metallic bismuth and aqueous sodium hypochlorite were the precursors to obtain the delta phase of bismuth oxide by LASL.•δ-Bi2O3 nanoparticle were synthetized by LASL.•Stable δ-Bi2O3 was obtained at ...room temperature.•Compositional, structural, and morphological features of the delta phase of bismuth oxide are reported.
δ-Bi2O3 nanoparticles (NPs) were successfully synthesized by using the laser ablation of solids in liquids (LASL) technique. This is the first time, to the best of our knowledge, that the δ-Bi2O3 phase is obtained through this synthesis method. A bismuth target immersed in sodium hypochlorite as liquid medium was irradiated with a ns-pulsed Nd:YAG laser. Our results indicate that LASL is a suitable and simple technique to obtaining δ-Bi2O3.
Display omitted
•Metalic manganese and deionized water were the precursors to obtain manganese oxide NPs by LASL.•MnO and Mn3O4 NPs were synthetized by LASL.•MnO NPs evolved into Mn3O4 NPs by ...conveniently increasing the total laser ablation time.•Compositional, optical, structural and morphological features of the manganese oxide NPs are reported.
Manganese oxide nanoparticles were synthesized, particularly the Mn3O4 phase, using the laser ablation of solids in liquids technique (LASL). The experiments were carried out by ablating a manganese (Mn) target immersed in deionized water as the liquid medium, with a pulsed Nd:YAG laser with a wavelength of 1064 nm. The effect of ablation time on the formation of these oxides was studied as an important parameter, which determines the final composition of the obtained products. The formed nanoparticles were optically characterized by UV-Vis spectroscopy, while Raman spectroscopy and X-Ray diffraction helped the purpose of characterizing the crystalline oxide phases. TEM results showed that the nanoparticles are well crystalized and have an approximate diameter between 7 and 11 nm.
Display omitted
•2D carbon nanostructures synthesis in colloidal suspension by laser fragmentation.•Laser fragmentation and ablation in liquids techniques to obtain MnOx NPs/C ...nanosheets.•Photoluminiscent MnOx NPs/C nanosheets composite based colloidal suspensions.
MnOxNPs/Cnanosheets composite based colloidal suspensions were synthesized using the laser ablation in liquids technique. The colloids were obtained by ablating a manganese target immersed in a carbon nanosheets suspension, which was previously prepared through laser fragmentation of microsized carbon powder suspended in acetone. The microsized carbon powder was characterized by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). The as-obtained nanostructures were characterized by Raman microspectroscopy and transmission electron microscopy (TEM). Raman microspectroscopy results indicate that the composite is constituted by manganese oxide (a mixture of the MnO and Mn3O4 crystalline phases) and carbon. TEM images show that the nanocomposite is composed by manganese oxide nanoparticles embedded in carbon nanosheets. The colloidal suspensions were studied by means of photoluminescence (PL). The two distinct colloidal suspensions (i. e. the carbon nanosheets colloid and the MnOx NPs/C nanosheets composite colloid) show PL. The carbon nanosheets PL is enhanced significantly (in the order of 2.5 times) when the MnOx NPs have been synthesized in the composite. Also, the MnOx NPs provide an intense UV emission to the composite. Several potential applications can be envisioned for this MnOx NPs/C nanosheets composite in the fields of opto-electronics and biomedicine.
Radiochromic film has become an important tool to verify dose distributions for intensity‐modulated radiotherapy (IMRT) and quality assurance (QA) procedures. A new radiochromic film model, EBT3, has ...recently become available, whose composition and thickness of the sensitive layer are the same as those of previous EBT2 films. However, a matte polyester layer was added to EBT3 to prevent the formation of Newton's rings. Furthermore, the symmetrical design of EBT3 allows the user to eliminate side‐orientation dependence. This film and the flatbed scanner, Epson Perfection V750, form a dosimetry system whose intrinsic characteristics were studied in this work. In addition, uncertainties associated with these intrinsic characteristics and the total uncertainty of the dosimetry system were determined. The analysis of the response of the radiochromic film (net optical density) and the fitting of the experimental data to a potential function yielded an uncertainty of 2.6%, 4.3%, and 4.1% for the red, green, and blue channels, respectively. In this work, the dosimetry system presents an uncertainty in resolving the dose of 1.8% for doses greater than 0.8 Gy and less than 6 Gy for red channel. The films irradiated between 0 and 120 Gy show differences in the response when scanned in portrait or landscape mode; less uncertainty was found when using the portrait mode. The response of the film depended on the position on the bed of the scanner, contributing an uncertainty of 2% for the red, 3% for the green, and 4.5% for the blue when placing the film around the center of the bed of scanner. Furthermore, the uniformity and reproducibility radiochromic film and reproducibility of the response of the scanner contribute less than 1% to the overall uncertainty in dose. Finally, the total dose uncertainty was 3.2%, 4.9%, and 5.2% for red, green, and blue channels, respectively. The above uncertainty values were obtained by minimizing the contribution to the total dose uncertainty of the film orientation and film homogeneity.
PACS number(s): 87.53.Bn
Chronic venous disease (CVD) comprises a spectrum of morphofunctional disorders affecting the venous system, affecting approximately 1 in 3 women during gestation. Emerging evidence highlights ...diverse maternofetal implications stemming from CVD, particularly impacting the placenta. While systemic inflammation has been associated with pregnancy-related CVD, preliminary findings suggest a potential link between this condition and exacerbated inflammation in the placental tissue. Inflammasomes are major orchestrators of immune responses and inflammation in different organs and systems. Notwithstanding the relevance of inflammasomes, specifically the NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3)- which has been demonstrated in the placentas of women with different obstetric complications, the precise involvement of this component in the placentas of women with CVD remains to be explored. This study employs immunohistochemistry and real-time PCR (RT-qPCR) to examine the gene and protein expression of key components in both canonical and non-canonical pathways of the NLRP3 inflammasome (NLRP3, ASC-apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain-caspase 1, caspase 5, caspase 8, and interleukin 1β) within the placental tissue of women affected by CVD. Our findings reveal a substantial upregulation of these components in CVD-affected placentas, indicating a potential pathophysiological role of the NLRP3 inflammasome in the development of this condition. Subsequent investigations should focus on assessing translational interventions addressing this dysregulation in affected patient populations.
BACKGROUNDPersistent controllers (PCs) maintain antiretroviral-free HIV-1 control indefinitely over time, while transient controllers (TCs) eventually lose virological control. It is essential to ...characterize the quality of the HIV reservoir in terms of these phenotypes in order to identify the factors that lead to HIV progression and to open new avenues toward an HIV cure.METHODSThe characterization of HIV-1 reservoir from peripheral blood mononuclear cells was performed using next-generation sequencing techniques, such as full-length individual and matched integration site proviral sequencing (FLIP-Seq; MIP-Seq).RESULTSPCs and TCs, before losing virological control, presented significantly lower total, intact, and defective proviruses compared with those of participants on antiretroviral therapy (ART). No differences were found in total and defective proviruses between PCs and TCs. However, intact provirus levels were lower in PCs compared with TCs; indeed the intact/defective HIV-DNA ratio was significantly higher in TCs. Clonally expanded intact proviruses were found only in PCs and located in centromeric satellite DNA or zinc-finger genes, both associated with heterochromatin features. In contrast, sampled intact proviruses were located in permissive genic euchromatic positions in TCs.CONCLUSIONSThese results suggest the need for, and can give guidance to, the design of future research to identify a distinct proviral landscape that may be associated with the persistent control of HIV-1 without ART.FUNDINGInstituto de Salud Carlos III (FI17/00186, FI19/00083, MV20/00057, PI18/01532, PI19/01127 and PI22/01796), Gilead Fellowships (GLD22/00147). NIH grants AI155171, AI116228, AI078799, HL134539, DA047034, MH134823, amfAR ARCHE and the Bill and Melinda Gates Foundation.
•Small (5–8nm) ZnO nanoparticles synthetized with LASL technique.•Comparable SHG signal from random ZnO monocrystalline NPs and aggregated ZnO NPs.•Efficiency of the SHG process may not depend on the ...ZnO NPs size/aggregation.
We report the synthesis of small zinc oxide nanoparticles (ZnO NPs) based colloidal suspensions and the study of second-harmonic generation from aggregated ZnO NPs deposited on glass substrates. The colloidal suspensions were obtained using the laser ablation of solids in liquids technique, ablating a Zn solid target immersed in acetone as the liquid medium, with ns-laser pulses (1064nm) of a Nd-YAG laser. The per pulse laser fluence, the laser repetition rate frequency and the ablation time were kept constant. The absorption evolution of the obtained suspensions was optically characterized through absorption spectroscopy until stabilization. Raman spectroscopy, SEM and HRTEM were used to provide evidence of the ZnO NPs structure. HRTEM results showed that 5–8nm spheroids ZnO NPs were obtained. Strong second-harmonic signal is obtained from random ZnO monocrystalline NPs and from aggregated ZnO NPs, suggesting that the high efficiency of the nonlinear process may not depend on the NPs size or aggregation state.
Purpose
The aim of this work is to investigate the effects of immersing EBT3 radiochromic film in water and to evaluate its contribution to the total uncertainty in dose determination.
Materials and ...methods
We used 3 cm × 3 cm EBT3 radiochromic films irradiated in the range of 0–70 Gy to study the impact of water immersion on the change in net optical density. These films were placed in a water container for a period of 24 h. The net optical density was measured before (0 h) and after of the immersion in water (1, 3, 6, 12, 18, and 24 h). The absorbance spectrum of the EBT3 radiochromic film was measured at 0 h and 24 h after immersion in water. The uncertainty in dose determination due to the effects of keeping the EBT3 radiochromic film submerged in water at 0, 1, and 24 h were recorded in the red, green, and blue channels.
Results
We observed an increase in the net optical density as an effect on the film due to its immersion in water. The penetration of the water at the edges of the radiochromic film was observed to be a function of time during which the film remained in the water. On the other hand, the penetration of water at the edges of the film was found to be independent of irradiation dose.
Conclusions
EBT3 radiochromic film is found more resistant to water penetration through the edges than its predecessors. However, there is evidence that suggest that liquid water damage the Nylon cover layer of the film by changing its optical properties. Therefore, it is recommended to build a new calibration curve for radiochromic films for a specific situation involving dose measurements in liquid water.
In this work we present experimental results on the optical characterization of carbon-nanoparticles (CNPs) synthesized by the laser ablation of solids in liquids technique (LASL). A pulsed Nd-YAG ...laser, a graphite disk and acetone were used in the laser ablation experiments. The per pulse laser fluence was varied, while all the other irradiation parameters (irradiation time, repetition rate, etc.) were kept constant. Both the graphite target and the obtained CNPs were characterized by Raman micro-spectroscopy. The colloidal solutions were characterized by UV–vis and photoluminescence (PL) spectroscopies. Additionally, the CNPs were also characterized by TEM and HRTEM. Our results show that spherical nanoparticles in the range of 4–20nm in diameter were obtained. UV–vis and PL results for the obtained CNPs colloidal solutions showed that the optical absorption and PL intensity are dependent on the per pulse laser fluence. We also found that the PL spectral emission of the CNPs can be tuned from blue to yellow by varying the excitation wavelength.
•LASL is a simple and fast technique to obtain CNPs colloidal solutions.•CNPs colloidal solution PL intensity depends on the per pulse laser fluence.•The PL of CNPs prepared by LASL is tunable for different excitation wavelength.
PDF
