Mobility and wellbeing during the covid-19 lockdown. Evidence from Spain.

The lockdown of March and April 2020 declared by Spanish authorities in the Valencian Region to bending the Covid-19 curve, caused a drastic reduction of the economic activity and a severe limitation of mobility. People were asked to stay at home as much as possible. Education and administrative centers, as well as restaurants, theaters, sport arenas, etc., were closed. Work at conventional workplaces was prohibited for people who could tele-work, and students were compelled to attend classes on-line. Such limitation of mobility and spending so many time at home, could affect the wellbeing of people. The objective of the present paper is to present a study on the differences on wellbeing according to the mobility of respondents during the lockdown. Information from 1,827 individuals regarding the satisfaction of the basic psychological needs (Autonomy, Competence and Relatedness) and Positive and Negative affect were collected through and web-survey during the first lockdown of the Covid-19 pandemic, together with mobility data and sociodemographic characteristics. Mann-Whitney U tests, Confirmatory Factor Analyses and Structural Equation models are used to find out differences in the wellbeing of people according to their mobility characteristics during the first lockdown, and how these mobility characteristics are associated to the psychological variables studied. Mobility of people during the first lockdown reduced drastically, especially the youngest ones, and the main travel mode was walking. In general, the youngest participants in this research and females present lower values of the psychological wellbeing variables during the lockdown. A very low or very high degree of mobility is also associated to discomfort, although the more time spent traveling the better people feel. Those who walked more are related to lower values of wellbeing. Some lessons are learned to improve transport and mobility planning during a pandemic.

Understanding the Driving Mechanisms of Enhanced Luminescence Emission of Oligo(styryl)benzenes and Tri(styryl)-s-triazine.

This work is focused on unraveling the mechanisms responsible for the aggregation-induced enhanced emission and solid-state luminescence enhancement effects observed in star-shaped molecules based on 1,3,5-tris(styryl)benzene and tri(styryl)-s-triazine cores. To achieve this, the photophysical properties of this set of molecules were analyzed in three states: free molecules, molecular aggregates in solution, and the solid state. Different spectroscopy and microscopy experiments and DFT calculations were conducted to scrutinize the causative mechanisms of the luminescence enhancement phenomenon observed in some experimental conditions. Enhanced luminescence emission was interpreted in the context of short- and long-range excitonic coupling mechanisms and the restriction of intramolecular vibrations. Additionally, we found that the formation of π-stacking aggregates could block E/Z photoisomerization through torsional motions between phenylene rings in the excited state, and hence, enhancing the luminescence of the system.

Assessment of Nocturnal Autonomic Cardiac Imbalance in Positional Obstructive Sleep Apnea. A Multiscale Nonlinear Approach.

Positional obstructive sleep apnea (POSA) is a major phenotype of sleep apnea. Supine-predominant positional patients are frequently characterized by milder symptoms and less comorbidity due to a lower age, body mass index, and overall apnea-hypopnea index. However, the bradycardia-tachycardia pattern during apneic events is known to be more severe in the supine position, which could affect the cardiac regulation of positional patients. This study aims at characterizing nocturnal heart rate modulation in the presence of POSA in order to assess potential differences between positional and non-positional patients. Patients showing clinical symptoms of suffering from a sleep-related breathing disorder performed unsupervised portable polysomnography (PSG) and simultaneous nocturnal pulse oximetry (NPO) at home. Positional patients were identified according to the Amsterdam POSA classification (APOC) criteria. Pulse rate variability (PRV) recordings from the NPO readings were used to assess overnight cardiac modulation. Conventional cardiac indexes in the time and frequency domains were computed. Additionally, multiscale entropy (MSE) was used to investigate the nonlinear dynamics of the PRV recordings in POSA and non-POSA patients. A total of 129 patients (median age 56.0, interquartile range (IQR) 44.8-63.0 years, median body mass index (BMI) 27.7, IQR 26.0-31.3 kg/m2) were classified as POSA (37 APOC I, 77 APOC II, and 15 APOC III), while 104 subjects (median age 57.5, IQR 49.0-67.0 years, median BMI 29.8, IQR 26.6-34.7 kg/m2) comprised the non-POSA group. Overnight PRV recordings from positional patients showed significantly higher disorderliness than non-positional subjects in the smallest biological scales of the MSE profile (τ = 1: 0.25, IQR 0.20-0.31 vs. 0.22, IQR 0.18-0.27, p < 0.01) (τ = 2: 0.41, IQR 0.34-0.48 vs. 0.37, IQR 0.29-0.42, p < 0.01). According to our findings, nocturnal heart rate regulation is severely affected in POSA patients, suggesting increased cardiac imbalance due to predominant positional apneas.

Effect of five-membered ring and heteroatom substitution on charge transport properties of perylene discotic derivatives: A theoretical approach.

Density functional theory calculations were carried out to investigate the evolvement of charge transport properties of a set of new discotic systems as a function of ring and heteroatom (B, Si, S, and Se) substitution on the basic structure of perylene. The replacement of six-membered rings by five-membered rings in the reference compound has shown a prominent effect on the electron reorganization energy that decreases ∼0.2 eV from perylene to the new carbon five-membered ring derivative. Heteroatom substitution with boron also revealed to lower the LUMO energy level and increase the electron affinity, therefore lowering the electron injection barrier compared to perylene. Since the rate of the charge transfer between two molecules in columnar discotic systems is strongly dependent on the orientation of the stacked cores, the total energy and transfer integral of a dimer as a disc is rotated with respect to the other along the stacking axis have been predicted. Aimed at obtaining a more realistic approach to the bulk structure, the molecular geometry of clusters made up of five discs was fully optimized, and charge transfer rate and mobilities were estimated for charge transport along a one dimensional pathway. Heteroatom substitution with selenium yields electron transfer integral values ∼0.3 eV with a relative disc orientation of 25°, which is the preferred angle according to the dimer energy profile. All the results indicate that the tetraselenium-substituted derivative, not synthetized so far, could be a promising candidate among those studied in this work for the fabrication of n-type semiconductors based on columnar discotic liquid crystals materials.

Theoretical estimation of the optical bandgap in a series of poly(aryl-ethynylene)s: a DFT study.

Aimed to optimize the ratio accuracy/computational cost, in this work we study the performance of three different theoretical methodologies in the calculation of the optical bandgap for a test set made of a number of poly(aryl-ethynylene)s related polymers. Infinite, ideal polymer chains were first optimized by means of periodic calculations. Different length oligomers were afterward generated by direct replication of the corresponding periodic structure and their optical bandgaps were calculated by means of different time dependent-density functional theory (TD-DFT) methodologies. These results were fitted to an exponential function for each oligomer family in order to get a theoretical estimation of the optical bandgap for each polymer to be compared to the experimental reported values. The best result was obtained for TD-M06-2X yielding an average deviation of 3.4% with respect to the experimental values.

Anomalous ascending pharyngeal artery arising from the internal carotid artery: report of three cases.

Anomalous branches from the internal carotid artery (ICA) have been reported rarely in the literature. We report three cases of ascending pharyngeal arising from the ICA. It is essential to be aware of these variations in carotid artery surgery.

Barriers and Facilitators in Access to Diabetes, Hypertension, and Dyslipidemia Medicines: A Scoping Review.

Objective: Identify barriers and facilitators in access to medicines for diabetes, hypertension, and dyslipidemia, considering patient, health provider, and health system perspectives. Methods: Scoping review based on Joanna Briggs methodology. The search considered PubMed, Cochrane Library, CINAHL, Academic Search Ultimate, Web of Science, SciELO Citation Index, and grey literature. Two researchers conducted screening and eligibility phases. Data were thematically analyzed. Results: The review included 219 documents. Diabetes was the most studied condition; most of the evidence comes from patients and the United States. Affordability and availability of medicines were the most reported dimension and specific barrier respectively, both cross-cutting concerns. Among high- and middle-income countries, identified barriers were cost of medicines, accompaniment by professionals, long distances to facilities, and cultural aspects; cost of transportation emerges in low-income settings. Facilitators reported were financial accessibility, trained health workers, medicines closer to communities, and patients' education. Conclusion: Barriers and facilitators are determined by socioeconomic and cultural conditions, highlighting the role of health systems in regulatory and policy context (assuring financial coverage and free medicines); providers' role bringing medicines closer; and patients' health education and disease management.

Dynamic Excimer (DYNEX) Imaging of Lipid Droplets.

Unraveling cellular physiological processes via luminescent probes that target specific cellular microenvironments is quite challenging due to the uneven distribution of probes. Herein, we designed a new dynamic excimer (DYNEX) imaging method that involves the sensitive detection of nanosecond-scale dynamic molecular contacts of a fluorescent acridone derivative and reveals the cell microenvironment polarity. Using our method, we specifically tracked cell lipid droplets in fibroblast colon carcinoma cells. These organelles play a central role in metabolic pathways, acting as energy reservoirs in regulatory processes. DYNEX imaging provides the inner polarity of cell lipid droplets, which can be related to lipid contents and metabolic dysfunctions. This new methodology will inspire development of novel multidimensional fluorescent sensors that are able to provide target-specific and orthogonal information at the nanosecond scale.

Density functional theory study of the optical and electronic properties of oligomers based on phenyl-ethynyl units linked to triazole, thiadiazole, and oxadiazole rings to be used in molecular electronics.

In the present work, we have studied from a theoretical perspective the geometry and electronic properties of the series of related compounds 2,5-bis(phenylethynyl)-1,3,4-thiadiazole, 2,5-bis(phenylethynyl)-1,3,4-oxadiazole, and 2,5-bis(phenylethynyl)-1,2,4-triazole as candidates for electron-conducting polymers and compounds with desirable (opto)electronic properties. The effect of the ethynyl group (-C[Triple Bond]C-) on the structure and electronic properties was also studied. The influence of planarity on electrical conductivity has been studied by a natural-bond-orbital analysis. The (opto)electronic properties and conducting capability were investigated through the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap, excitation energy, bond length alternation, LUMO energy, electron affinities, and intramolecular reorganization energy. Finally, the evolution of some properties such as optical bandgap and electron affinity with the increase of the number of repeat units in the oligomer chain has been checked.

A machine learning-based test for adult sleep apnoea screening at home using oximetry and airflow.

The most appropriate physiological signals to develop simplified as well as accurate screening tests for obstructive sleep apnoea (OSA) remain unknown. This study aimed at assessing whether joint analysis of at-home oximetry and airflow recordings by means of machine-learning algorithms leads to a significant diagnostic performance increase compared to single-channel approaches. Consecutive patients showing moderate-to-high clinical suspicion of OSA were involved. The apnoea-hypopnoea index (AHI) from unsupervised polysomnography was the gold standard. Oximetry and airflow from at-home polysomnography were parameterised by means of 38 time, frequency, and non-linear variables. Complementarity between both signals was exhaustively inspected via automated feature selection. Regression support vector machines were used to estimate the AHI from single-channel and dual-channel approaches. A total of 239 patients successfully completed at-home polysomnography. The optimum joint model reached 0.93 (95%CI 0.90-0.95) intra-class correlation coefficient between estimated and actual AHI. Overall performance of the dual-channel approach (kappa: 0.71; 4-class accuracy: 81.3%) significantly outperformed individual oximetry (kappa: 0.61; 4-class accuracy: 75.0%) and airflow (kappa: 0.42; 4-class accuracy: 61.5%). According to our findings, oximetry alone was able to reach notably high accuracy, particularly to confirm severe cases of the disease. Nevertheless, oximetry and airflow showed high complementarity leading to a remarkable performance increase compared to single-channel approaches. Consequently, their joint analysis via machine learning enables accurate abbreviated screening of OSA at home.

Effectiveness of a multifactorial intervention, consisting of self-management of antihypertensive medication, self-measurement of blood pressure, hypocaloric and low sodium diet, and physical exercise, in patients with uncontrolled hypertension taking 2 or more antihypertensive drugs: The MEDICHY study.

INTRODUCTION: High blood pressure is the leading modifiable risk factor for cardiovascular disease, and is associated with high morbidity and mortality and with significant health care costs for individuals and society. However, fewer than half of the patients with hypertension receiving pharmacological treatment have adequate blood pressure control. The main reasons for this are therapeutic inertia, lack of adherence to treatment, and unhealthy lifestyle (i.e., excess dietary fat and salt, sedentary lifestyle, and overweight). Cardiovascular risk and mortality are greater in hypertensive patients who are receiving treatment but have suboptimal control of blood pressure. METHODS/DESIGN: This is a multicentre, parallel, 2-arm, single-blind (outcome assessor), controled, cluster-randomized clinical trial. General practitioners and nurses will be randomly allocated to the intervention group (self-management of antihypertensive medication, self-measurement of blood pressure, hypocaloric and low sodium diet, and physical exercise) or the control group (regular clinical practice). A total of 424 patients in primary care centers who use 2 or more antihypertensive drugs and blood pressure of at least 130/80 during 24-hambulatory blood pressure monitoring will be recruited. The primary outcome is systolic blood pressure at 12 months. The secondary outcomes are blood pressure control (<140/90 mm Hg); quality of life (EuroQol 5D); direct health care costs; adherence to use of antihypertensive medication; and cardiovascular risk (REGICOR and SCORE scales). DISCUSSION: This trial will be conducted in the primary care setting and will evaluate the impact of a multifactorial intervention consisting of self-management of blood pressure, antihypertensive medications, and lifestyle modifications (hypocaloric and low sodium diet and physical exercise).

Theoretical study of the effect of ethynyl group on the structure and electrical properties of phenyl-thiadiazole systems as precursors of electron-conducting materials.

2,5-Bis(phenylethynyl)-1,3,4-thiadiazole (PhEtTh) and 2,5-diphenyl-1,3,4-thiadiazole (PhTh) are expected to be building blocks for polymer materials that could be employed to conduct electricity due to their narrow highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gaps. In this work, a theoretical, comparative study about the effect of the ethynyl group on the planarity and electrical conductivity of this kind of systems has been carried out. Thus, several ab initio (Hartree-Fock, Moller-Plesset) and DFT (B3LYP, B3PW91, M05, M05-2X) methods and basis sets (6-31G(*), 6-31G+G(**), 6-311G(**), cc-pVDZ, cc-pVTZ) have been tested. As a result, PhEtTh showed better properties for its use as electric conducting material relative to PhTh due to its smaller HOMO-LUMO gap, as well as its enhanced trend to retain the planarity provided the reduction in steric hindrances that the ethynyl group (-C[triple bond]C-) permits. Solvent effects were also modeled for ethanol and chloroform under the conductor-like polarizable continuum model approximation. Finally, electronic transitions in gas and solution phases were predicted by using TDDFT approximation in order to compare the theoretical lambda(max) with the experimental values reported in literature for both compounds.

Cardiovascular risk and blood pressure control in a Spanish hypertensive population attended in a Primary Care setting. Data from the PRESCAP 2006 study.

AIMS: To analyse the cardiovascular risk of a broad sample of hypertensive patients and to examine whether there are differences in blood pressure control and associated factors according to the different cardiovascular risk categories. MAJOR FINDINGS: A total of 10,520 patients > or = 18 years old were included (mean age 64.6+/-11.3 years; 53.7% women). In this cohort, 3.3% were average risk, 22.6% low added risk, 22.2% moderate added risk, 33.5% high added risk and 18.4% very high added risk. Blood pressure was controlled in 41.4% (95% CI 40.5-42.4) of the total population, in 91.7% of patients with low added risk, in 19.4% with moderate added risk, in 27.4% with high added risk and in 6.8% with very high added risk. Diabetes was the factor most strongly associated with poor blood pressure control in patients with high to very high added risk (OR=7.2; p<0.0001). PRINCIPAL CONCLUSION: More than half of the hypertensive patients treated in primary health care have a high or very high added cardiovascular risk. In these patients, blood pressure control is inadequate and diabetes is associated with a sevenfold increase in the likelihood of poor blood pressure control.

Population dynamics based on mobile phone data to improve air pollution exposure assessments.

Air pollution is one of the greatest challenges cities are facing today and improving air quality is a pressing need to reduce negative health impacts. In order to efficiently evaluate which are the most appropriate policies to reduce the impact of urban pollution sources (such as road traffic), it is essential to conduct rigorous population exposure assessments. One of the main limitations associated with those studies is the lack of information about population distribution in the city along the day (population dynamics). The pervasive use of mobile devices in our daily lives opens new opportunities to gather large amounts of anonymized and passively collected geolocation data allowing the analysis of population activity and mobility patterns. This study presents a novel methodology to estimate population dynamics from mobile phone data based on a user-centric mobility model approach. The methodology was tested in the city of Madrid (Spain) to evaluate population exposure to NO2. A comparison with traditional census-based methods shows relevant discrepancies at disaggregated levels and highlights the need to incorporate mobility patterns into population exposure assessments.

Chemiluminescent determination of EDTA and related compounds using tris(2,2'-bipyridyl)ruthenium(III) photogenerated on-line.

A rapid and sensitive chemiluminescence method using flow-injection has been developed for the determination of EDTA. The method is based on the chemiluminescent reaction of EDTA with tris(2,2'-bipyridyl)ruthenium(III), which is generated on-line through the photooxidation of tris(2,2'-bipyridyl)ruthenium(II) with peroxydisulfate. After optimizing the different experimental parameters, a calibration graph was obtained over the concentration range of 7 x 10(-8) M to 3 x 10(-6) M, with a minimum detectability of 7.2 x 10(-9) M (S/N = 3) observed. The correlation coefficient was 0.9992 (n = 8). The repeatability was 0.88 % (for a level of 4 x 10(-7) M) expressed as the relative standard deviation (n = 10), and the reproducibility (studied on five consecutive days) was 1.5%. The method was successfully applied to the determination of EDTA in ophthalmic collyrium and sauce samples. The method is also useful for determining other aminopolycarboxylic acids, such as NTA, EGTA, DTPA, DCTA and EDDS.

Kinetic and theoretical study of the reaction of Cl atoms with a series of linear thiols.

The reactions of Cl with a series of linear thiols: 1-propanethiol (k(1)), 1-butanethiol (k(2)), and 1-pentanethiol (k(3)) were investigated as a function of temperature (in the range of 268-379 K) and pressure (in the range of 50-200 Torr) by laser photolysis-resonance fluorescence. Only 1-propanethiol has previously been studied, but at 1 Torr of total pressure. The derived Arrhenius expressions obtained using our kinetic data were as follows: k(1)=(3.97+/-0.44)x10(-11) exp[(410+/-36)T], k(2)=(1.01+/-0.16)x10(-10) exp[(146+/-23)T], and k(3)=(1.28+/-0.10)x10(-10) exp[(129+/-25)T] (in units of cm(3) molecule(-1) s(-1)). Moreover, a theoretical insight into mechanisms of these reactions has also been pursued through ab initio Moller-Plesset second-order perturbation treatment calculations with 6-311G(**) basis set. Optimized geometries have been obtained for transition states and molecular complexes appearing along the different reaction pathways. Furthermore, molecular energies have been calculated at QCISD(T) level in order to get an estimation of the activation energies. Finally, the nature of the molecular complexes and transitions states is analyzed by using kinetic-potential and natural bond orbital total energy decomposition schemes.

[Control of blood pressure in Spanish hypertensive population attended in primary health-care. PRESCAP 2006 Study]. / Control de la presión arterial en la población hipertensa española atendida en atención primaria. Estudio PRESCAP 2006.

BACKGROUND AND OBJECTIVES: More information is needed on hypertension control and its evolution in clinical practice. This study aimed to determine the degree of blood pressure (BP) control in Spanish hypertensive patients attended in primary care (PC) and to determine the factors associated with poor BP control. PATIENTS AND METHOD: Cross-sectional, multicenter study, carried out in PC settings throughout Spain. Hypertensive patients >or= 18 years, with antihypertensive treatment (>or= 3 months) were consecutively recruited. BP measurement was performed in surgery hours (morning and evening) following standardized methods and averaging 2 consecutive readings. BP control was regarded as optimum when BP values were < 140/90 mmHg in general population and <130/80 mmHg in patients with diabetes, chronic renal disease or cardiovascular disease. RESULTS: 10,520 hypertensive patients were included (53.7% women), mean age (SD) 64.6 (11.3) years. 41.4% (95% confidence interval [CI], 40.5-42.4) presented good systolic BP (SBP) and diastolic BP (DBP) control, 46.5% (95% CI, 45.5-47.4) only SBP control and 67.1% (95% CI, 66.2-68.0) only DBP control. 55.6% of patients were treated with combination therapy (41.2% 2 drugs, 11.7% 3 and 2.8% more than 3). BP control was significantly (p<0.001) higher in the evening measurement (48.9%) than in the morning measurement (40.5%), and if patients had taken the treatment before measurement (42.0%) compared with those who had not taken it (38.8%). Factors such as diabetes, cardiovascular disease, sedentary lifestyle, alcohol consumption and surgery hour were associated with poor BP control (p<0.001). CONCLUSIONS: The results of the PRESCAP 2006 study indicate that 4 out of 10 hypertensive patients treated in PC in Spain have an optimal BP control. The degree of control of arterial hypertension has improved remarkably with respect to the PRESCAP 2002 study.

Determination of N-methylcarbamate pesticides in environmental samples by an automated solid-phase extraction and liquid chromatographic method based on post-column photolysis and chemiluminescence detection.

An automated solid-phase extraction-high performance liquid chromatography method has been developed to determine trace concentration of N-methylcarbamate pesticides in water and fruits. The method is based on the post-column conversion of the pesticides into methylamine by irradiation with UV light. The resultant methylamine was subsequently detected by chemiluminescence using tris(2,2'-bipyridyl)ruthenium(III), which was on-line generated by photo-oxidation of the ruthenium(II) complex with peroxydisulfate. Factors affecting the rate of the reactions were optimized so that their contribution to the total band-broadening was negligible. This detection system was used to determine bendiocarb, carbaryl, promecarb and propoxur, which were separated on an ODS C(18) column. The mobile phase consisted of water and acetonitrile using a gradient elution. A linear relationship between peak area and concentration was obtained for all pesticides (r(2)>0.999). Intra- and inter-day precision values of about 0.64-1.3% RSD (n=10) and 2.2-2.8% RSD (n=15), respectively, were obtained. N-Methylcarbamate pesticide residues at ultratrace levels could be determined in environmental samples when an automated solid-phase extraction device was coupled on-line with the HPLC system. Detection limits were within the range 3.9-36.7 ngl(-1) for water samples and 0.5-4.7 microgkg(-1) for fruits.

High-performance liquid chromatography-post-column chemiluminescence determination of aminopolycarboxylic acids at low concentration levels using tris(2,2'-bipyridyl)ruthenium(III).

A simple, selective and sensitive method for the determination of aminopolycarboxylic acids [diethylenetriaminepentaacetic acid (DTPA), S,S-ethylenediamine N,N'-disuccinic acid (EDDS), ethylenediaminetetraacetate (EDTA) and nitrilotriacetate (NTA)] has been developed using high-performance liquid chromatography with chemiluminescence detection. The aminopolycarboxylic acids were separated on a C18 reversed-phase column with an aqueous sulfuric acid mobile phase at a pH lower than 1.5. The eluate was mixed with tris(2,2'-bipyridyl)ruthenium(III), which was on-line generated by photooxidation of the ruthenium(II) complex in the presence of peroxydisulfate, and the generated chemiluminescence was detected. Calibration graphs, based on standard solutions, were linear over the range 8x10(-9) to 4x10(-5) M. The detection limits at a signal-to-noise ratio of 3 ranged from 9x10(-10) to 8x10(-8) M. The relative standard deviations of intra- and inter-day precision were below 1.3% and 2.1%, respectively. This HPLC system was successfully applied to the determination of aminopolycarboxylic acids in three different types of water samples. The low pH of the mobile phase limits interference from metal ions in natural waters. When such interference occurs, a cation-exchange column can be used to suppress it. The lowest amounts measurable were: 75 pg for NTA, 0.7 ng for EDDS, 0.8 ng for DTPA and 12ng for EDTA. The method was also applied for the EDTA assay in canned foods.

High-performance liquid chromatography: photochemical reduction in aerobic conditions for determination of K vitamins using fluorescence detection.

The development and application of a post-column detection system for K vitamins based on their photoreduction to the hydroquinone form is reported. The photoreduction yield is practically quantitative and occurs in a PTFE tubing coiled around a 6-W low-pressure mercury lamp in the presence of sodium dodecylsulfate and methanol. Factors affecting the rate of the photochemical reaction were optimised so that its contribution to the total broadening was negligible. The enhanced fluorescence and stability of the K vitamins reduced in micellar medium has permitted the use of a very sensitive photochemical detection system, which can work in aerobic conditions. Separations were carried out by reverse-phase chromatography using pure methanol as eluent. The determination of phylloquinone, menaquinone-4 and menadione in several real samples illustrates the potential of the photochemical detection system.