Method development and validation for acrylamide in potato cutlet by UHPLC-MS/MS

Surge in consumption of healthy and safe foods has challenged researchers to develop sensitive, precise, robust detection and quantification of food contaminants like acrylamide even if they are present in trace. Keeping this in view, a robust and sensitive analytical method was developed and validated for acrylamide quantification in a potato-based food product (potato cutlet), using LC-MSMS with positive electrospray ionization (+ESI). The method consists of adding acrylamide-d3 (deuterium labelled acrylamide) as an internal standard, extraction by modified QuEChERS method with d-SPE clean-up. Extracts were run on a reverse phase C-18 column for analysis by liquid chromatography. The limit of detection (LOD) and limit of quantification (LOQ) were determined as 0.7 and 2.0 μg kg− 1 , respectively, demonstrating the sensitivity of the method for trace detection. The developed method showed excellent results in terms of recoveries (91.0–109.16%), repeatability (RSD 1.8–10.60%), reproducibility (RSD 2.3–11.24%) and robustness (RSD 1.74–4.54%). The repeatability, reproducibility and robustness respectively, show the consistency, accuracy and stability of the developed method. The deviations in ion ratio and retention time were 17.25% and − 0.01 min, respectively. Compared to previous findings, the current study has achieved lower LOD and LOQ levels that reveals the higher sensitivity of this method for acrylamide quantification in potato cutletMinistry of Food Processing Industries, Government of India | Ref. Q-29/11/2018-R&DUniversidade de Vigo/CISU

Antiangiogenic activity of zinc and zinc-sorafenib combination using the chick chorioallantoic membrane assay: a descriptive study

Background: Zinc, a trace element, is known for downregulating several proangiogenic growth factors and cytokines. However, its antiangiogenic activity is not adequately studied. The present study was aimed to evaluate the possible antiangiogenic activity of zinc via the chick chorioallantoic membrane (CAM) assay. Also, the antiangiogenic activity of the combination therapy of zinc with various doses of sorafenib, a tyrosine kinase inhibitor, was evaluated.Methods: A pilot study was initially conducted so as to select suitable doses of zinc and sorafenib. The antiangiogenic activity after combining zinc 2.5 μg/embryo with sorafenib 1, and 2 μg/embryo was also evaluated. The antiangiogenic activity was quantified in terms of total length of blood vessels, number of junctions, number of branching points, and mean length of the blood vessels.Results: Zinc 2.5 μg/embryo showed significant (p 0.05) to that of sorafenib 2 μg/embryo.Conclusions: Zinc caused significant antiangiogenic activity in the CAM assay. The lack of addition/synergism in the zinc-sorafenib combination could have been due to the variability in the dose/ratio selection. Addition of zinc to sorafenib therapy could improve treatment tolerability, reduce cost of therapy, and reduce the emergence of drug resistance. Future mechanistic studies could identify the exact pharmacodynamics of zinc as an angiogenesis inhibitor

Dynamic and Thermodynamic Influences on Precipitation in Northeast Mexico on Orbital to Millennial Timescales

The timing and mechanisms of past hydroclimate change in northeast Mexico are poorly constrained, limiting our ability to evaluate climate model performance. To address this, we present a multiproxy speleothem record of past hydroclimate variability spanning 62.5 to 5.1 ka from Tamaulipas, Mexico. Here we show a strong influence of Atlantic and Pacific sea surface temperatures on orbital and millennial scale precipitation changes in the region. Multiple proxies show no clear response to insolation forcing, but strong evidence for dry conditions during Heinrich Stadials. While these trends are consistent with other records from across Mesoamerica and the Caribbean, the relative importance of thermodynamic and dynamic controls in driving this response is debated. An isotope-enabled climate model shows that cool Atlantic SSTs and stronger easterlies drive a strong inter-basin sea surface temperature gradient and a southward shift in moisture convergence, causing drying in this region

Causes and Impacts of Rainfall Variability In Central Mexico on Multiple Timescales

The eastern sector of Mexico’s Trans-Mexican Volcanic Belt is a semi-arid region, where interannual rainfall variability is significantly stresses regional water resources and the livelihood of millions. The region is linked to a broader summertime rainfall regime known as the North American Monsoon (NAM). My dissertation uses multiple lines of evidence, from geochemistry to climate model output, to understand the causes of long-term droughts in this region.My first dissertation chapter uses instrumental data to diagnose the causes of El Niño-induced droughts in Mexico. This work explores the mechanisms responsible for rainfall changes over Central Mexico during the developing versus decaying phase of an El Niño event. This study was the first to demonstrate the importance of moisture transport anomalies in reducing rainfall in highland Mexico during the decay phase of an El Niño. My second dissertation chapter uses the oxygen stable isotope ratios (δ18O) of lacustrine carbonates as well as elemental geochemistry to reconstruct late Holocene drought in Central Mexico. This sub-centennially resolved record is the first to identify a significant dry interval in central Mexico from 1300-1100 cal yr. B.P., which may be temporally coherent with increased drought frequencies recorded on the Yucatan Peninsula. These results also hint at a role for climate change in regional prehistoric cultural changes at the nearby site of Cantona. My third dissertation chapter explores impacts of late Holocene droughts on the terrestrial ecosystems in Central Mexico. I reconstructed past vegetation and fire dynamics from pollen and microscopic charcoal, and compared these data to our stable-isotope based climate reconstruction and regional archaeological records. My fourth chapter is an exploration of the causes of centennial-scale across Mexico and Central America in the late Holocene. This work identifies the spatiotemporal patterns of late Holocene drought by synthesizing Mesoamerican proxy records. It presents a new hypothesis pointing to the role of changes in Atlantic circulation in causing droughts in Mesoamerica. Finally, I synthesize the knowledge in each of the dissertation chapters and point to avenues of future research

Causes and Impacts of Rainfall Variability In Central Mexico on Multiple Timescales

The eastern sector of Mexico’s Trans-Mexican Volcanic Belt is a semi-arid region, where interannual rainfall variability is significantly stresses regional water resources and the livelihood of millions. The region is linked to a broader summertime rainfall regime known as the North American Monsoon (NAM). My dissertation uses multiple lines of evidence, from geochemistry to climate model output, to understand the causes of long-term droughts in this region.My first dissertation chapter uses instrumental data to diagnose the causes of El Niño-induced droughts in Mexico. This work explores the mechanisms responsible for rainfall changes over Central Mexico during the developing versus decaying phase of an El Niño event. This study was the first to demonstrate the importance of moisture transport anomalies in reducing rainfall in highland Mexico during the decay phase of an El Niño. My second dissertation chapter uses the oxygen stable isotope ratios (δ18O) of lacustrine carbonates as well as elemental geochemistry to reconstruct late Holocene drought in Central Mexico. This sub-centennially resolved record is the first to identify a significant dry interval in central Mexico from 1300-1100 cal yr. B.P., which may be temporally coherent with increased drought frequencies recorded on the Yucatan Peninsula. These results also hint at a role for climate change in regional prehistoric cultural changes at the nearby site of Cantona. My third dissertation chapter explores impacts of late Holocene droughts on the terrestrial ecosystems in Central Mexico. I reconstructed past vegetation and fire dynamics from pollen and microscopic charcoal, and compared these data to our stable-isotope based climate reconstruction and regional archaeological records. My fourth chapter is an exploration of the causes of centennial-scale across Mexico and Central America in the late Holocene. This work identifies the spatiotemporal patterns of late Holocene drought by synthesizing Mesoamerican proxy records. It presents a new hypothesis pointing to the role of changes in Atlantic circulation in causing droughts in Mesoamerica. Finally, I synthesize the knowledge in each of the dissertation chapters and point to avenues of future research

Spatial variability and mechanisms underlying El Nino-induced droughts in Mexico

The El Niño Southern Oscillation plays a key role in modulating interannual rainfall variability in Mexico. While El Niño events are linked to drought in Mexico, uncertainty exists about the spatial pattern and causal mechanisms behind El Niño-induced drought. We use lead/lag correlation analysis of rainfall station data to identify the spatial pattern of drought associated with the summer before, and the spring following, the peak of warm SST anomalies in the eastern equatorial Pacific. We also use atmospheric fields from the North American Regional Reanalysis to calculate the anomalous moisture budget and diagnose the mechanisms associated with El Niño-induced drought in Mexico. We find that reduced rainfall occurs in Mexico in both the summer before and the spring after a peak El Niño event, especially in regions of climatologically strong convection. The teleconnection in the developing phase of El Niño is primarily driven by changes in subsidence resulting from anomalous convection in the equatorial Pacific. The causes of drought during the decaying phase of El Niño events are varied: in some years, descent anomalies dominate other moisture budget terms, while in other years, drying of the boundary layer on the Mexican plateau is important. We suggest that the latter may result from the interaction of weakened southeasterly winds in the Intra-Americas Sea with high topography along the Atlantic coast of Mexico. Weakened winds are likely driven by a reduced sea level pressure gradient between the Atlantic and the Pacific. Changes in easterly wave activity may contribute to drought in the developing phase of El Niño, but may be less important in the decaying phase of El Niño

Spatial variability and mechanisms underlying El Nino-induced droughts in Mexico

The El Niño Southern Oscillation plays a key role in modulating interannual rainfall variability in Mexico. While El Niño events are linked to drought in Mexico, uncertainty exists about the spatial pattern and causal mechanisms behind El Niño-induced drought. We use lead/lag correlation analysis of rainfall station data to identify the spatial pattern of drought associated with the summer before, and the spring following, the peak of warm SST anomalies in the eastern equatorial Pacific. We also use atmospheric fields from the North American Regional Reanalysis to calculate the anomalous moisture budget and diagnose the mechanisms associated with El Niño-induced drought in Mexico. We find that reduced rainfall occurs in Mexico in both the summer before and the spring after a peak El Niño event, especially in regions of climatologically strong convection. The teleconnection in the developing phase of El Niño is primarily driven by changes in subsidence resulting from anomalous convection in the equatorial Pacific. The causes of drought during the decaying phase of El Niño events are varied: in some years, descent anomalies dominate other moisture budget terms, while in other years, drying of the boundary layer on the Mexican plateau is important. We suggest that the latter may result from the interaction of weakened southeasterly winds in the Intra-Americas Sea with high topography along the Atlantic coast of Mexico. Weakened winds are likely driven by a reduced sea level pressure gradient between the Atlantic and the Pacific. Changes in easterly wave activity may contribute to drought in the developing phase of El Niño, but may be less important in the decaying phase of El Niño