Application of surface-enhanced resonance Raman spectroscopy to chlorophyll and chlorophyll derivatives

Chlorophylls and chlorophyll derivatives are fundamental components of green plants and are directly involved in light trapping and electron transfer during photosynthesis. In Sections 1-3 surface-enhanced resonance Raman spectroscopy (SERRS) has been employed to obtain Raman vibrational spectra for chlorophyll a, pheophytin a, and chlorophyll b adsorbed on a roughened silver electrode and excited from within the Soret band to the lowest energy transition in the red at 77K. Cooling to liquid nitrogen temperature was found to improve the spectral quality by minimizing sample heating and photooxidation. Most significantly, the fluorescence accompanying red excitation was quenched at the roughened Ag surface at low temperature and this resulted in richly detailed SERRS spectra. Distinctive SERRS spectra were obtained for each excitation wavelength. Selective excitation within the various electronic transitions can thus be utilized to verify assignments of the vibrational modes of the chlorophylls and pheophytin a and to monitor their interactions and photochemical behavior in biomimetic systems and in vivo;Metal electrodes are preferable for SERRS studies of photosynthetic pigments because the electrogenerated species can be created and monitored with minimal sample manipulation and chemical interference. Although the roughened silver electrode provides intense Raman spectra for the neutral photosynthetic pigments, its oxidation potential is too low for SERRS studies of electron transfer reactions involving chlorophyll a in vitro and/or in vivo within the light harvesting and reaction center complexes of green plants. Roughened gold provides surface enhancement with red excitation. While this is a narrower spectral enhancement range than for silver, Au can provide information on the RR spectrum coupled to the lowest [pi]-[pi][superscript]* transitions, about which little is known because of fluorescence problems. In addition, Au has a broader electrochemical range that is well suited for all the photosynthetic pigments. Thus, in Section 4 a roughened gold electrode was investigated as a SERRS substrate for chlorophyll a, pheophytin a, and chlorophyll b with red excitation at 77K. Distinct spectra of each of the photosynthetic pigments were obtained from the roughened Au electrode demonstrating that it is a viable SERRS substrate. Also, Au provides a means to monitor electron transfer in photosynthetic systems by excitation within the lowest electronic transition

Do dried blood spots have the potential to support result management processes in routine sports drug testing?—Part 3: LC–MS/MS‐based peptide analysis for dried blood spot sampling time point estimation

Along with the recent acknowledgement of the World Anti-Doping Agency to use dried blood spot (DBS) samples for routine doping control purposes, there have been propositions to use DBS as a matrix that allows regular proactive remotely supervised self-sampling, providing potential longitudinal monitoring of an athlete's exposure to doping agents. However, several organizational aspects have to be considered before implementation, such as the verification of the sample collections time point. Based on a previous untargeted proteomics workflow utilizing liquid chromatography–high-resolution mass spectrometry (LC–HRMS) to identify protein/peptide markers to define the time since deposition of a bloodstain, the aim of the current study was to develop a targeted LC–HRMS/MS analytical method for promising peptidic target analytes. A long-term DBS storage experiment was carried out over a 3-month period (sample collection time points: 0, 2, 4, 7, 14, 21, 28, 42, 56, 70, 84 and 91 days) with DBS samples of 10 volunteers for longitudinal investigation of signal abundance changes of targeted peptide sequences at different storage temperatures (room temperature [RT], 4°C and −20°C). Prior to experimental analysis, LC–HRMS/MS method characteristics were successfully assessed, including intraday precision, carryover and sample extract stability. For estimation of DBS sample collection time points, ratios of two peptides that originate from the same protein prior to tryptic digestion were created. Two targeted peptide area ratios were found to significantly increase after being stored at RT for 28 days, representing potential markers for future use in routine doping controls that contribute to advancing complementary avenues in anti-doping

Effect of fire induced water repellency on soil hydraulic properties and water flow

Water infiltration into the root zone, its retention in soil and drainage from the soil profile, are highly sensitive to the presence, degree and persistence of soil water repellency (SWR). Prolonged drought periods and wildfires can increase SWR substantially, thus    the aim of this study was to determine the effect of forest fire-induced water repellency    on soil hydraulic properties, infiltration and water flow in unsaturated soil (vadose) zone. Infiltration experiments with water and ethanol were conducted on forest sites, selected according to their exposure to fire: heavily burned (A), burned (B) and non-affected as the control site (C). Infiltration data were used as an input for inverse determination of soil hydraulic parameters required for computer model calibration (HYDRUS 2D/3D). Then, a one-year climatic scenario for 2016 with measured meteorological data was simulated using HYDRUS-1D software. Data showed that in the case of soil exposure to high temperatures (forest fires), a relatively large increase of SWR is observed. Compared to the control plot, a considerably greater difference between the hydraulic conductivity, Ks, values for water and ethanol was found at both fire affected plots. This suggested positive relationship between soil water repellency and reduced water infiltration. Numerical simulation of the intensive (extreme) rainfall event clearly showed that SWR affects soil water balance by reducing the infiltration and increasing the surface runoff

Use of Online Food Delivery Services to Order Food Prepared Away-From-Home and Associated Sociodemographic Characteristics: A Cross-Sectional, Multi-Country Analysis

Online food delivery services like Just Eat and Grubhub facilitate online ordering and home delivery of food prepared away-from-home. It is poorly understood how these services are used and by whom. This study investigated the prevalence of online food delivery service use and sociodemographic characteristics of customers, in and across Australia, Canada, Mexico, the UK, and the USA. We analyzed online survey data (n = 19,378) from the International Food Policy Study, conducted in 2018. We identified respondents who reported any online food delivery service use in the past 7 days and calculated the frequency of use and number of meals ordered. We investigated whether odds of any online food delivery service use in the past 7 days differed by sociodemographic characteristics using adjusted logistic regression. Overall, 15% of respondents (n = 2929) reported online food delivery service use, with the greatest prevalence amongst respondents in Mexico (n = 839 (26%)). Online food delivery services had most frequently been used once and the median number of meals purchased through this mode of order was two. Odds of any online food delivery service use were lower per additional year of age (OR: 0.95; 95% CI: 0.94, 0.95) and greater for respondents who were male (OR: 1.50; 95% CI: 1.35, 1.66), that identified with an ethnic minority (OR: 1.57; 95% CI: 1.38, 1.78), were highly educated (OR: 1.66; 95% CI: 1.46, 1.90), or living with children (OR: 2.71; 95% CI: 2.44, 3.01). Further research is required to explore how online food delivery services may influence diet and health

Metabolomic Strategies in Biomarker Research–New Approach for Indirect Identification of Drug Consumption and Sample Manipulation in Clinical and Forensic Toxicology?

Drug of abuse (DOA) consumption is a growing problem worldwide, particularly with increasing numbers of new psychoactive substances (NPS) entering the drug market. Generally, little information on their adverse effects and toxicity are available. The direct detection and identification of NPS is an analytical challenge due to their ephemerality on the drug scene. An approach that does not directly focus on the structural detection of an analyte or its metabolites, would be beneficial for this complex analytical scenario and the development of alternative screening methods could help to provide fast response on suspected NPS consumption. A metabolomics approach might represent such an alternative strategy for the identification of biomarkers for different questions in DOA testing. Metabolomics is the monitoring of changes in small (endogenous) molecules (<1,000 Da) in response to a certain stimulus, e.g., DOA consumption. For this review, a literature search targeting “metabolomics” and different DOAs or NPS was conducted. Thereby, different applications of metabolomic strategies in biomarker research for DOA identification were identified: (a) as an additional tool for metabolism studies bearing the major advantage that particularly a priori unknown or unexpected metabolites can be identified; and (b) for identification of endogenous biomarker or metabolite patterns, e.g., for synthetic cannabinoids or also to indirectly detect urine manipulation attempts by chemical adulteration or replacement with artificial urine samples. The majority of the currently available literature in that field, however, deals with metabolomic studies for DOAs to better assess their acute or chronic effects or to find biomarkers for drug addiction and tolerance. Certain changes in endogenous compounds are detected for all studied DOAs, but often similar compounds/pathways are influenced. When evaluating these studies with regard to possible biomarkers for drug consumption, the observed changes appear, albeit statistically significant, too small to reliably work as biomarker for drug consumption. Further, different drugs were shown to affect the same pathways. In conclusion, metabolomic approaches possess potential for detection of biomarkers indicating drug consumption. More studies, including more sensitive targeted analyses, multi-variant statistical models or deep-learning approaches are needed to fully explore the potential of omics science in DOA testing

Control of gene expression during T cell activation: alternate regulation of mRNA transcription and mRNA stability

BACKGROUND: Microarray technology has become highly valuable for identifying complex global changes in gene expression patterns. The effective correlation of observed changes in gene expression with shared transcription regulatory elements remains difficult to demonstrate convincingly. One reason for this difficulty may result from the intricate convergence of both transcriptional and mRNA turnover events which, together, directly influence steady-state mRNA levels. RESULTS: In order to investigate the relative contribution of gene transcription and changes in mRNA stability regulation to standard analyses of gene expression, we used two distinct microarray methods which individually measure nuclear gene transcription and changes in polyA mRNA gene expression. Gene expression profiles were obtained from both polyA mRNA (whole-cell) and nuclear run-on (newly transcribed) RNA across a time course of one hour following the activation of human Jurkat T cells with PMA plus ionomycin. Comparative analysis revealed that regulation of mRNA stability may account for as much as 50% of all measurements of changes in polyA mRNA in this system, as inferred by the absence of any corresponding regulation of nuclear gene transcription activity for these groups of genes. Genes which displayed dramatic elevations in both mRNA and nuclear run-on RNA were shown to be inhibited by Actinomycin D (ActD) pre-treatment of cells while large numbers of genes regulated only through altered mRNA turnover (both up and down) were ActD-resistant. Consistent patterns across the time course were observed for both transcribed and stability-regulated genes. CONCLUSION: We propose that regulation of mRNA stability contributes significantly to the observed changes in gene expression in response to external stimuli, as measured by high throughput systems

Examining associations between classroom environment and processes and early mathematics performance from pre-kindergarten to kindergarten.

One benefit of the No Child Left Behind legislation (2001) has been the increasing attention on the importance of the skills learned in the pre-kindergarten period for later academic achievement. There is a growing awareness that mathematics skills in kindergarten and beyond are influenced by the formal and informal mathematics skills acquired in the pre-kindergarten classroom. In recent years, a body of research has emerged pointing to the contributions to children’s learning from pre-kindergarten program quality as indexed by structure and process elements in the classroom. Results from this study point to three major findings. First, the growth of mathematics skills from pre-kindergarten to kindergarten for the full sample varied between classes but was not significantly associated with the elements of the classroom environment selected for study. Second, classroom elements were differentially related to growth of mathematics scores depending on children’s scores at pre-kindergarten entry. Third, overall differences between high- and low-performing children at pre-kindergarten entry are evident in their growth through kindergarten

Lower school performance in late chronotypes: underlying factors and mechanisms

Success at school determines future career opportunities. We described a time-of-day specific disparity in school performance between early and late chronotypes. Several studies showed that students with a late chronotype and short sleep duration obtain lower grades, suggesting that early school starting times handicap their performance. How chronotype, sleep duration, and time of day impact school performance is not clear. At a Dutch high school, we collected 40,890 grades obtained in a variety of school subjects over an entire school year. We found that the strength of the effect of chronotype on grades was similar to that of absenteeism, and that late chronotypes were more often absent. The difference in grades between the earliest 20% and the latest 20% of chronotypes corresponds to a drop from the 55th to 43rd percentile of grades. In academic subjects using mainly fluid cognition (scientific subjects), the correlation with grades and chronotype was significant while subjects relying on crystallised intelligence (humanistic/linguistic) showed no correlation with chronotype. Based on these and previous results, we can expand our earlier findings concerning exam times: students with a late chronotype are at a disadvantage in exams on scientific subjects, and when they are examined early in the day

Interaction of sexual dimorphism and gene dosage imbalance in skeletal deficits associated with Down syndrome

All individuals with Down syndrome (DS), which results from trisomy of human chromosome 21 (Ts21), present with skeletal abnormalities typified by craniofacial features, short stature and low bone mineral density (BMD). Differences in skeletal deficits between males and females with DS suggest a sexual dimorphism in how trisomy affects bone. Dp1Tyb mice contain three copies of all of the genes on mouse chromosome 16 that are homologous to human chromosome 21, males and females are fertile, and therefore are an excellent model to test the hypothesis that gene dosage influences the sexual dimorphism of bone abnormalities in DS. Dp1Tyb as compared to control littermate mice at time points associated with bone accrual (6 weeks) and skeletal maturity (16 weeks) showed deficits in BMD and trabecular architecture that occur largely through interactions between sex and genotype and resulted in lower percent bone volume in all female and Dp1Tyb male mice. Cortical bone in Dp1Tyb as compared to control mice exhibited different changes over time influenced by sex × genotype interactions including reduced cortical area in both male and female Dp1Tyb mice. Mechanical testing analyses suggested deficits in whole bone properties such as bone mass and geometry, but improved material properties in female and Dp1Tyb mice. Sexual dimorphisms and the influence of trisomic gene dosage differentially altered cellular properties of male and female Dp1Tyb bone. These data establish sex, gene dosage, skeletal site and age as important factors in skeletal development of DS model mice, paving the way for identification of the causal dosage-sensitive genes. Skeletal differences in developing male and female Dp1Tyb DS model mice replicated differences in less-studied adolescents with DS and established a foundation to understand the etiology of trisomic bone deficits