16 research outputs found
Copper Indium Sulfide Quantum Dots as Nanomanometers: Influence of Size and Composition
Mechanical forces control the function of organisms and mediate theinteraction between biological systems and their environments. Knowledge ofthese forces will increase the understanding of biological processes and cansupport the development of novel diagnostic and therapeutic procedures.Although techniques like atomic force microscopy and droplet insertionmethod allow measuring forces over a broad range of values, they are invasiveand lack versatility. A promising way to overcome these hurdles isluminescent nanomanometry. Quantum dots (QDs) specifically have opticalproperties that depend on their size because of the quantum confinement,which makes them responsive to applied forces. Yet, a fine understanding ofhow fundamental parameters affect the response to applied stress is requiredbefore a QD family can be credibly proposed as luminescentnanomanometers. Here, a thorough study is conducted on how size andstoichiometry affect the nanomanometry performance of CuInS2QDs. Thestudied QDs feature pressure-dependent photoluminescence in thered/near-infrared range, which can enable the measurement of mechanicalforces in the range of physiological relevance in a remote and minimallyinvasive way. It is shown that tuning size and stoichiometry cansimultaneously enhance the CuInS2QDs’ brightness and response to appliedpressure, thus providing guidelines for better luminescent nanomanometers
Optical Temperature Sensor Capabilities of the Green Upconverted Luminescence of Er3+ in La3NbO7 Ceramic Powders
We present a study of the Er3+ upconverted luminescence in erbium doped Lanthanum
Niobium Oxide, La3NbO7, ceramic powder, prepared by solid state reaction. This study focuses
on the analysis of the feasibility of this system as a temperature sensor. Efficient UC luminescence
was observed under the 975 nm excitation showing intense green, red and NIR (850 nm) emission
bands. The NIR luminescence centred at about 850 nm and lying on the first biological window is
mainly insensitive to the temperature. In contrast, the upconverted green bands, associated with
the (2H11/2,4S3/2) !4I15/2 transitions, showed a high sensibility to temperature. Their temperature
dependence was studied from RT up to 525 K, paying special attention to the physiological range of
temperature (303–318 K). The high thermal sensitivities obtained, in comparison with other Er3+ and
Er3+-Yb3+ based optical temperature sensors in such ranges, suggest the potential application of this
phosphor in thermal sensing, suitable for both biological systems and other industrial applications
requiring higher temperatures.This research has been partially supported by the Spanish Ministerio de Ciencia, Innovación
y Universidades (MICINN) through the Spanish projects RTI2018-101020-B-100 and PID2019-
106383GB-C44, by the Madrid Government (Comunidad de Madrid-Spain) under the Multiannual
Agreement with UC3Min the line of Excellence of University Professors (EPUC3MXX) and in the context
of the V PRICIT (Regional Programme of Research and Technological Innovation) by the Agencia
Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI) (ProID2017010078).
M.A.H.-R. thanks MINECO for the FPI grant (BES-2014-068666). U.R.R.-M.
thanks Gobierno de Canarias and EU-FEDER for grant ProID2020010067
Optical nanothermometer based on the calibration of the Stokes and upconverted green emissions of Er3+ ions in Y3Ga5O12 nano-garnets
The temperature-dependent green luminescence of Y3Ga5O12 nano-garnets doped with different concentrations of Er3+ ions has been measured from 300 to 850 K and, in more detail, in the biological range from 292 to 335 K. The green emissions were obtained by excitation under 488 nm blue or 800 nm near-infrared laser radiations. Both excitations give rise to bright green luminescence that can be seen by the naked eye, and which can be associated either with Stokes processes, i.e. multiphonon relaxations followed by green spontaneous emission, in the former case or with infrared-to-visible upconversion processes in the latter. The temperature-induced changes in the Er3+ green emissions have been calibrated for both excitations and results point to a strong dependence on the concentration of optically active Er3+ ions. The maximum value of the thermal sensitivity, 64 × 10−4 K−1 at 547 K, has been obtained for the nano-garnets doped with the lowest concentration of Er3+ ions, which is one of the highest values found in the literature. These results allow to conclude that a relatively low concentration of optically active ions is advisable and the changes induced by temperature on the green emissions are independent of the laser excitation radiation used, which is necessary to calibrate the temperature of the immediate environment of the Er3+-doped Y3Ga5O12 nano-garnets.This work have been partially supported by Ministerio de
Economía y Competitividad de España (MINECO) under The
National Program of Materials (MAT2010-21270-C04-02/-03,
and MAT2013-46649-C4-3-P/-4-P), The Consolider-Ingenio
2010 Program (MALTA CSD2007-00045), and the Indo-
Spanish Joint Programme of Cooperation in Science and
Technology (PRI-PIBIN-2011-1153/DST-INT-Spain-P-38-11),
and by the EU-FEDER funds. V. Venkatramu is also grateful to
Council of Scientific and Industrial Research (CSIR), New
Delhi for the sanction of major research project (No.
03(1229)/12/EMR-II, dated: 16th April, 2012). V. Monteseguro
wishes to thank MICINN for the FPI grant (BES-2011-
044596)
2D Cu(I)‑I Coordination Polymer with Smart Optoelectronic Properties and Photocatalytic Activity as a Versatile Multifunctional Material
This work presents two isostructural Cu(I)-I 2-fluoropyrazine (Fpyz) luminescent
and semiconducting 2D coordination polymers (CPs). Hydrothermal synthesis allows the growth
of P-1 space group single crystals, whereas solvent-free synthesis produces polycrystals. Via
recrystallization in acetonitrile, P21 space group single crystals are obtained. Both show a reversible
luminescent response to temperature and pressure. Structure determination by single-crystal X-ray
diffraction at 200 and 100 K allows us to understand their response as a function of temperature.
Applying hydrostatic/uniaxial pressure or grinding also generates significant variations in their
emission. The high structural flexibility of the Cu(I)-I chain is significantly linked to the
corresponding alterations in structure. Remarkably, pressure can increase the conductivity by up to 3 orders of magnitude. Variations
in resistivity are consistent with changes in the band gap energy. The experimental results are in agreement with the DFT
calculations. These properties may allow the use of these CPs as optical pressure or temperature sensors. In addition, their behavior
as a heterogeneous photocatalyst of persistent organic dyes has also been investigatedThanks to Micro and Nanotechnology Institute CNM-CSIC
for SEM images. Thanks to the SCXRD laboratory of the
Interdepartmental Research Service and to Servicios Generales
de Apoyo a la Investigación (SEGAI) at La Laguna University.
This work has been supported by MCINN/AEI/ 10.13039/
5011000011033 under the National Program of Sciences and
Technological Materials, PID2019-108028GB-C22, PID2019-
106383GB-C41/C44, and TED2021-131132B-C22. Thanks to
Gobierno d e Canarias and EU-FEDER (grant:
ProID2020010067). This study forms part of the Advanced
Materials program and was supported by MCIN with funding
from European Union Next Generation EU (PRTR-C17.I1)
and by Generalitat Valenciana (grant MFA/2022/007 and
PROMETEO CIPROM/2021/075-GREENMAT). A.L.
(R.T.) and D.E. thank the Generalitat Valenciana for the
Ph.D. (Postdoctoral) Fellowship No. GRISOLIAP/2019/025
(CIAPOS/2021/20). J.C.G. and R. W. acknowledge the
support from the Spanish Ministry of Science and Innovation
(RTI2018-097508-B-I00, PID2021-128313OB-I00, TED2021-
131018B-C22) and the Regional Government of Madrid
through projects NMAT2D-CM (S2018/NMT-4511). J.C.G.
acknowledges support from the Regional Government of
Madrid through “Proyectos Sinérgicos de I + D” (grant
Y2018/NMT-5028 FULMATEN-CM) and NANOCOV-CM
(REACT-UE). IMDEA Nanociencia acknowledges support
from the Severo Ochoa Programme for Centres of Excellence
in R&D (MINECO, grant CEX2020-001039-S
Cunning defects: Emission control by structural point defects on Cu(i)I double chain coordination polymers
The following version is an accepted manuscript in Journal of Materials Chemistry C 8.4 (2020): 1448-1458 and may be found at ttps://doi.org/10.1039/C9TC05185FThe direct reaction between CuI and 3,5-dichloropyridine, in acetonitrile at room temperature, gives rise to [Cu(Cl2-py)I]n (Cl2-py = 3,5-dichloropyridine), which consists of a Cu(i)-I double chain based coordination polymer (CP) grafted with 3,5-dichloropyridine. In this simple one-pot process, the modulation of the reaction conditions, i.e. slight variations in the CuI and Cl2-py ratio caused by in situ disproportion, can, however, produce significant changes in the physical properties of the materials. For instance, the reaction carried out in a 1 : 1 ratio under ambient conditions leads to compound 1, while compound 1′ is obtained upon a solvothermal process of stoichiometric reaction mixture, Cl2-py and CuI, which produces partial disproportion (<0.5% in weight) of the initial Cu(i). Interestingly, compounds 1 and 1′ show an identical chemical composition and structure as determined by both single crystal and powder X-ray diffraction. However, they display remarkable differences in the luminescence behavior, featuring broad emission bands centered at 515 and 670 nm and associated to photoluminescence quantum yields of 12 and 5% for 1 and 1′, respectively. Density functional theory (DFT) calculations allowed us to rationalize the nature of this rare behavior. This is attributed to structural defects related to the weaker coordination bond present in these structures that provoke the strong red-shifted emissionThe authors thank financial support from the Spanish Ministerio de Economıa y Competitividad (MAT2016-77608-C3-1-P,
MAT2016-75883-C2-2-P, MAT2010-20843-C02-01, CTQ2016-75816-
C2-1P, MAT2016-75586-C4-4-P) and by EU-FEDER funds. JGP
thanks to Servicios Generales de Apoyo a la Investigacion (SEGAI)
at La Laguna University. J. I. M. acknowledges the financial support
by the ‘‘Ramo´n y Cajal’’ Program of MINECO (Grant RYC-2015-
17730) and the EU via the ERC-Synergy Program (Grant ERC-2013-
SYG-610256 NANOCOSMOS). J. C. E. acknowledges the financialsupport by the ‘‘FPI-MINECO’’ Program of MINECO (Grant BES2015-071534). R. D. C. acknowledges the program ‘‘Ayudas para la
atraccio´n de talento investigador—Modalidad 1 of the Consejerı´a de Educacio´n, Juventud y Deporte—Comunidad de
Madrid with the Reference No. 2016-T1/IND-1463.’’, Spanish
MINECO for the Ramo´n y Cajal program (RYC-2016-20891), the
Europa Excelencia program (ERC2019-092825), and HYNANOSC (RTI2018-099504-A-C22). R. D. C. also acknowledges the
2018 Leonardo Grant for Researchers and Cultural Creators
from BBVA Foundation and the FOTOART-CM project funded
by Madrid region under programm P2018/NMT-4367. J. F.-C.
acknowledges the Marie Skłodowska-Curie Individual Fellowships (H2020-MSCA-IF-2017). This paper is dedicated to Dmitri
Mendele´yev in honour of the 150th anniversary of the discovery
of the periodic tabl
Does Size Matters? Relationships among Social Dominance and Some Morphometric Traits upon Out-of-Season Reproductive Outcomes in Anestrus Dairy Goats Treated with P4 + eCG
The possible role of the social rank (R) (i.e., low-LSR, middle-MSR, or high-HSR) in anestrus goats exposed to a P4 + eCG (D) (i.e., 100 or 350 IU) estrus induction protocol (EIP) was evaluated. Goats (Alpine-Saanen-Nubian × Criollo; n = 70; 25° North) managed under stall-fed conditions were all ultrasound evaluated to confirm anestrous status, while the social rank was determined 30 d prior to the EIP. The response variables included estrus induction (EI, %), duration of estrus (DUR, h), ovulation rate (OR, n), live weight (LW, kg), thoracic perimeter (TP, cm), thoracic diameter (TD, cm), body length (BL, cm), height at withers (HW, cm), beard length (BEA, cm), compactness index (COM, cm), and anamorphosis index (ANA, cm), as affected by R, D, and the R × D interaction were evaluated, while the correlation coefficients among reproductive and morphometric variables were quantified. An R × D interaction (p 0.05) with any response variable, either reproductive or morphometric. As expected, LW had high correlation coefficients (p < 0.01) with TP (0.86), TD (0.88), BL (0.82), HW (0.75), BEA (0.51), COM (0.97), and ANA (0.75). In general, the morphometric variables as a whole demonstrated important correlation coefficients among them (p < 0.01), ranging from 0.38 up to 0.84. To estimate the importance of the morphometric differences between social rank upon estrus induction, a principal component (PC) analysis was performed based on the correlation matrix derived from the corporal measurements. The PC1 and PC2 explained 70.3% and 17.6% of the morphometric variation, respectively. The PC1 was a measure of the goat size (i.e., small, medium, large) and its association with estrus occurrence was evaluated using a logistic regression model; the bigger the goat, the increased probability of being in estrus, by up to five times compared to small goats. Our results confirm that the higher social ranked, larger goats amalgamated some fundamental factors to be successful: aggressiveness, primacy to food access, augmented live weight, and corporal size; all of these were able to modulate out-of-season reproductive success in crossbred dairy goats subjected to an estrus induction protocol and managed under stall-fed conditions in Northern Mexico
Synthesis, structure and luminescence of Er3+-doped Y3Ga5O12 nano-garnets
A novel Y3(1-x)Er3xGa5O12 nanocrystalline garnet has been synthesized by a sol-gel technique and a complete structural, morphological, vibrational, and optical characterization has been carried out in order to correlate the local structure of the Er3+ ions with their optical properties. The synthesized nanocrystals are found in a single-phase garnet structure with an average grain size of around 60 nm. The good crystalline quality of the garnet structure is confirmed by FTIR and Raman measurements, since the phonon modes of the nano-garnet are similar to those found in the single crystal garnet. Under blue laser excitation, intense green and red visible and 1.5 mu m infrared luminescences are observed, whose relative intensities are very sensitive to the Er3+ concentration. The dynamics of these emissions under pulsed laser excitations are analyzed in the framework of different energy transfer interactions. Intense visible upconverted luminescence can be clearly observed by the naked eye for all synthesized Er3+-doped Y3Ga5O12 nano-garnets under a cw 790 nm laser excitation. The power dependency and the dynamics of the upconverted luminescence confirm the existence of different two-photon upconversion processes for the green and red emissions that strongly depend on the Er3+ concentration, showing the potential of these nano-garnets as excellent candidates for developing new optical devices.This work has been partially supported by Ministerio de Ciencia e Innovacion of Spain (MICCIN) under The National Program of Materials (MAT2010-21270-C04-02; -03; -04), The Consolider-Ingenio 2010 Program (MALTA CSD2007-0045), and The National Infrastructure Program, by Ministerio de Economia y Competitividad of Spain (MINECO) within The Indo-Spanish Joint Programme of Cooperation in Science and Technology (PRI-PIBIN-2011-1153/DST-INT-Spain-P-38-11), and by the EU-FEDER funds (UCAN08-4E-008). S.F. Leon-Luis and V. Monteseguro wish to thank MICINN for the FPI grants (BES-2008-003353 and BES-2011-044596). Dr V. Venkatramu is grateful to DAE-BRNS, Government of India for the award of DAE Research Award for Young Scientists (no. 2010/20/34/5/BRNS/2223).Venkatramu, V.; León-Luis, SF.; Rodriguez-Mendoza, UR.; Monteseguro, V.; Manjón, FJ.; Lozano-Gorrín, AD.; Valiente, R.... (2012). Synthesis, structure and luminescence of Er3+-doped Y3Ga5O12 nano-garnets. Journal of Materials Chemistry. 22:13788-13799. doi:10.1039/c2jm31386cS13788137992
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection