Two-photon Absorption and Photoionization of a Bacterial Phytochrome

Phytochromes constitute a family of photosensory proteins that are utilized by various organisms to regulate several physiological processes. Phytochromes bind a bilin pigment that switches its isomeric state upon absorption of red or far-red photons, resulting in protein conformational changes that are sensed by the organism. Previously, the ultrafast dynamics in bacterial phytochrome was resolved to atomic resolution by time-resolved serial femtosecond X-ray diffraction (TR-SFX), showing extensive changes in its molecular conformation at 1 picosecond delay time. However, the large excitation fluence of mJ/mm2 used in TR-SFX questions the validity of the observed dynamics. In this work, we present an excitation-dependent ultrafast transient absorption study to test the response of a related bacterial phytochrome to excitation fluence. We observe excitation power-dependent sub-picosecond dynamics, assigned to the population of high-lying excited state Sn through resonantly enhanced two-photon absorption, followed by rapid internal conversion to the low-lying S1 state. Inspection of the long-lived spectrum under high fluence shows that in addition to the primary intermediate Lumi-R, spectroscopic signatures of solvated electrons and ionized chromophore radicals are observed. Supported by numerical modelling, we propose that under excitation fluences of tens of μJ/mm2 and higher, bacterial phytochrome partly undergoes photoionization from the Sn state in competition with internal conversion to the S1 state in 300 fs. We suggest that the extensive structural changes of related, shorter bacterial phytochrome, lacking the PHY domain, resolved from TR-SFX may have been affected by the ionized species. We propose approaches to minimize the two-photon absorption process by tuning the excitation spectrum away from the S1 absorption or using phytochromes exhibiting minimized or shifted S1 absorption.

Transcriptome revealed the molecular mechanism of Glycyrrhiza inflata root to maintain growth and development, absorb and distribute ions under salt stress

BACKGROUND

Soil salinization extensively hampers the growth, yield, and quality of crops worldwide. The most effective strategies to counter this problem are a) development of crop cultivars with high salt tolerance and b) the plantation of salt-tolerant crops. Glycyrrhiza inflata, a traditional Chinese medicinal and primitive plant with salt tolerance and economic value, is among the most promising crops for improving saline-alkali wasteland. However, the underlying molecular mechanisms for the adaptive response of G. inflata to salinity stress remain largely unknown.

RESULT

G. inflata retained a high concentration of Na+ in roots and maintained the absorption of K+, Ca2+, and Mg2+ under 150 mM NaCl induced salt stress. Transcriptomic analysis of G. inflata roots at different time points of salt stress (0 min, 30 min, and 24 h) was performed, which resulted in 70.77 Gb of clean data. Compared with the control, we detected 2645 and 574 differentially expressed genes (DEGs) at 30 min and 24 h post-salt-stress induction, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that G. inflata response to salt stress post 30 min and 24 h was remarkably distinct. Genes that were differentially expressed at 30 min post-salt stress induction were enriched in signal transduction, secondary metabolite synthesis, and ion transport. However, genes that were differentially expressed at 24 h post-salt-stress induction were enriched in phenylpropane biosynthesis and metabolism, fatty acid metabolism, glycerol metabolism, hormone signal transduction, wax, cutin, and cork biosynthesis. Besides, a total of 334 transcription factors (TFs) were altered in response to 30 min and 24 h of salt stress. Most of these TFs belonged to the MYB, WRKY, AP2-EREBP, C2H2, bHLH, bZIP, and NAC families.

CONCLUSION

For the first time, this study elucidated the salt tolerance in G. inflata at the molecular level, including the activation of signaling pathways and genes that regulate the absorption and distribution of ions and root growth in G. inflata under salt stress conditions. These findings enhanced our understanding of the G. inflata salt tolerance and provided a theoretical basis for cultivating salt-tolerant crop varieties.

Preparation of Bamboo-Based Hierarchical Porous Carbon Modulated by FeCl3 towards Efficient Copper Adsorption

Using bamboo powder biochar as raw material, high-quality meso/microporous controlled hierarchical porous carbon was prepared—through the catalysis of Fe³⁺ ions loading, in addition to a chemical activation method—and then used to adsorb copper ions in an aqueous solution. The preparation process mainly included two steps: load-alkali leaching and chemical activation. The porosity characteristics (specific surface area and mesopore ratio) were controlled by changing the K₂CO₃ impregnation ratio, activation temperature, and Fe³⁺ ions loading during the activation process. Additionally, three FBPC samples with different pore structures and characteristics were studied for copper adsorption. The results indicate that the adsorption performance of the bamboo powder biochar FBPC material was greatly affected by the meso/micropore ratio. FBPC _2.5-900-2%, impregnated at a K₂CO₃: biochar ratio of 2.5 and a Fe³⁺: biochar mass ratio of 2%, and activated at 900 °C for 2 h in N₂ atmosphere, has a very high specific surface area of 1996 m² g⁻¹ with a 58.1% mesoporous ratio. Moreover, it exhibits an excellent adsorption capacity of 256 mg g⁻¹ and rapid adsorption kinetics for copper ions. The experimental results show that it is feasible to control the hierarchical pore structure of bamboo biochar-derived carbons as a high-performance adsorbent to remove copper ions from water.

Influence of Lactic Acid Surface Modification of Cellulose Nanofibrils on the Properties of Cellulose Nanofibril Films and Cellulose Nanofibril-Poly(lactic acid) Composites

In this study, cellulose nanofibrils (CNFs) were modified by catalyzed lactic acid esterification in an aqueous medium with SnCl2 as a catalyst. Films were made from unmodified and lactic acid-modified CNF without a polymer matrix to evaluate the effectiveness of the modification. Ungrafted and lactic acid-grafted CNF was also compounded with poly(lactic acid) (PLA) to produce composites. Mechanical, water absorption, and barrier properties were evaluated for ungrafted CNF, lactic acid-grafted CNF films, and PLA/CNF composites to ascertain the effect of lactic acid modification on the properties of the films and nanocomposites. FTIR spectra of the modified CNF revealed the presence of carbonyl peaks at 1720 cm-1, suggesting that the esterification reaction was successful. Modification of CNF with LA improved the tensile modulus of the produced films but the tensile strength and elongation decreased. Additionally, films made from modified CNF had lower water absorption, as well as water vapor and oxygen permeability, relative to their counterparts with unmodified CNFs. The mechanical properties of PLA/CNF composites made from lactic acid-grafted CNFs did not significantly change with respect to the ungrafted CNF. However, the addition of lactic acid-grafted CNF to PLA improved the water vapor permeability relative to composites containing ungrafted CNF. Therefore, the esterification of CNFs in an aqueous medium may provide an environmentally benign way of modifying the surface chemistry of CNFs to improve the barrier properties of CNF films and PLA/CNF composites.

Ionic Atmosphere Effect on the Absorption Spectrum of a Flavoprotein: A Reminder to Consider Solution Ions

This study utilizes the FMN-dependent NADH:quinone oxidoreductase from Pseudomonas aeruginosa PAO1 to investigate the effect of introducing an active site negative charge on the flavin absorption spectrum both in the absence and presence of a long-range electrostatic potential coming from solution ions. There were no observed changes in the flavin UV-visible spectrum when an active site tyrosine (Y277) becomes deprotonated in vitro. These results could only be reproduced computationally using average solvent electrostatic configuration (ASEC) QM/MM simulations that include both positive and negative solution ions. The same calculations performed with minimal ions to neutralize the total protein charge predicted that deprotonating Y277 would significantly alter the flavin absorption spectrum. Analyzing the distribution of solution ions indicated that the ions reorganize around the protein surface upon Y277 deprotonation to cancel the effect of the tyrosinate on the flavin absorption spectrum. Additional biochemical experiments were performed to test this hypothesis.

New Carvone-Based Deep Eutectic Solvents for Siloxanes Capture from Biogas

During biogas combustion, siloxanes form deposits of SiO₂ on engine components, thus shortening the lifespan of the installation. Therefore, the development of new methods for the purification of biogas is receiving increasing attention. One of the most effective methods is physical absorption with the use of appropriate solvents. According to the principles of green engineering, solvents should be biodegradable, non-toxic, and have a high absorption capacity. Deep eutectic solvents (DES) possess such characteristics. In the literature, due to the very large number of DES combinations, conductor-like screening models for real solvents (COSMO-RS), based on the comparison of siloxane activity coefficient of 90 DESs of various types, were studied. DESs, which have the highest affinity to siloxanes, were synthesized. The most important physicochemical properties of DESs were carefully studied. In order to explain of the mechanism of DES formation, and the interaction between DES and siloxanes, the theoretical studies based on σ-profiles, and experimental studies including the ¹H NMR, ¹³C NMR, and FT-IR spectra, were applied. The obtained results indicated that the new DESs, which were composed of carvone and carboxylic acids, were characterized by the highest affinity to siloxanes. It was shown that the hydrogen bonds between the active ketone group (=O) and the carboxyl group (-COOH) determined the formation of stable DESs with a melting point much lower than those of the individual components. On the other hand, non-bonded interactions mainly determined the effective capture of siloxanes with DES.

Chemical, physical, and functional properties of Thai indigenous brown rice flours

Thai indigenous brown rice flours from Nakhon Si Thammarat, Thailand, namely Khai Mod Rin (KMRF) and Noui Khuea (NKRF), were assessed for quality aspects in comparison with brown Jasmine rice flour (JMRF) and commercial rice flour (CMRF) from Chai Nat 1 variety. All the rice flours had different chemical composition, physical characteristic, and techno-functionality. The KMRF, NKRF, and JMRF were classified as a low amylose type (19.56-21.25% dw). All rice flours had low total extractable phenolic content (0.1-0.3 mg GAE/g dw) with some DPPH● scavenging activity (38.87-46.77%). The variations in the bulk density (1.36-1.83 g/cm3), water absorption capacity (0.71-1.17 g/g), solubility (6.93-13.67%), oil absorption capacity (1.39-2.49 g/g), and swelling power (5.71-6.84 g/g) were noticeable. The least gelation concentration ranged from 4.0 to 8.0% where KMRF was easier to form gel than JMRF, and NKRF/CMRF. The foam capacity of the flours was relatively low (1.30-2.60%). The pasting properties differed among rice flours and the lowest pasting temperature was observed in CMRF. Overall, the chemical, physical, functional, and pasting qualities of flours were substantially influenced by rice variety. The findings offered fundamental information on Thai indigenous rice flour that can be used in food preparations for specific uses.

Molecular docking studies, molecular dynamics and ADME/tox reveal therapeutic potentials of STOCK1N-69160 against papain-like protease of SARS-CoV-2

SARS-CoV-2 is a new strain of Coronavirus that caused the pneumonia outbreak in Wuhan, China and has spread to over 200 countries of the world. It has received worldwide attention due to its virulence and high rate of infection. So far, several drugs have experimented against SARS-CoV-2, but the failure of these drugs to specifically interact with the viral protease necessitates urgent measure to boost up researches for the development of effective therapeutics against SARS-CoV-2. Papain-like protease (PLpro) of the viral polyproteins is essential for maturation and infectivity of the virus, making it one of the prime targets explored for SARS-CoV-2 drug design. This study was conducted to evaluate the efficacy of ~ 50,000 natural compounds retrieved from IBS database against COVID-19 PLpro using computer-aided drug design. Based on molecular dock scores, molecular interaction with active catalytic residues and molecular dynamics (MD) simulations studies, STOCK1N-69160 [(S)-2-((R)-4-((R)-2-amino-3-methylbutanamido)-3-(4-chlorophenyl) butanamido) propanoic acid hydrochloride] has been proposed as a novel inhibitor against COVID-19 PLpro. It demonstrated favourable docking score, the free energy of binding, interacted with key amino acid residues necessary for PLpro inhibition and also showed significant moderation for parameters investigated for ADME/tox (Adsorption, distribution, metabolism, excretion and toxicological) properties. The edge of the compound was further established by its stability in MD simulation conducted for 30 ns employing GROMACS software. We propose that STOCK1N-69160 is worth further investigation for preventing SARS-CoV-2.

Resistant starch type 2 from lotus stem: Ultrasonic effect on physical and nutraceutical properties

Resistant starch type 2 (RS) was isolated from lotus stem using enzymatic digestion method. The isolated RS was subjected to ultrasonication (US) at different sonication power (100-400 W). The US treated and untreated RS samples were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), light microscopy and Fourier transform infrared spectroscopy (FT-IR). DLS revealed that particle size of RS decreased from 12.80 µm to 413.19 nm and zeta potential increased from -12.34 mV to -26.09 mV with the increase in sonication power. SEM revealed smaller, disintegrated and irregular shaped RS particles after ultrasonication. FT-IR showed the decreased the band intensity at 995 cm^-1 and 1047 cm^-1 signifying that US treatment decreased the crystallinity of RS and increased its amorphous character. The bile acid binding, anti-oxidant and pancreatic lipase inhibition activity of samples also increased significantly (p < 0.05) with the increase in sonication power. Increase in US power however increased the values of hydrolysis from 23.11 ± 1.09 to 36.06 ± 0.13% and gylcemic index from 52.39 ± 0.38 to 59.50 ± 0.11. Overall, the non-thermal process of ultrasonic treatment can be used to change the structural, morphological and nutraceutical profile of lotus stem resistant starch which can have great food and pharamaceutical applications.

Towards to understanding the preliminary loss and absorption of nitrogen and phosphorus under different treatments in cotton drip- irrigation in northwest Xinjiang

Drip irrigation under plastic mulch is widely used in Xinjiang, Northwest China. It can not only save water, but also reduce nutrient loss and improve fertilizer utilization. However, it is not clear whether the leaching occurs or not, what is the leaching amount? What is the relationship among fertilization, irrigation regimes, loss, cotton absorption, and cotton field under different fertilization and irrigation management under drip irrigation? Studying these issues not only provides reference for the formulation of fertilization and irrigation systems, but also is of great significance for reducing non-point source pollution. A long-term positioning experiment was conducted from 2009 to 2012 in Baotou Lake farm in Korla City, Xinjiang, with drip-irrigated cotton (Gossypium hirsutum L.) under different N fertilizer and irrigation amounts. The treatments were designed comprising Control (CK,0 N, 0 P, and 0 K with an irrigation of 480 mm) and the following three other treatments: (1) Conventional fertilize and irrigation (CON, 357 kg N hm^–2, 90 kg P hm^–2, 0 kg K hm^–2, and irrigation of 480 mm); (2) Conventional fertilization and Optimizing irrigation (OPT, 357 kg N hm^–2, 90 kg P hm^–2, 62 kg K hm^–2, and irrigation of 420 mm); and (3) Optimizing fertilization and irrigation (OPTN, 240 kg N hm^–2, 65 kg P hm^–2, 62 kg K hm^–2, and irrigation of 420 mm). The results found that the leaching would occur in arid area under drip irrigation. The loss of total N, NH₄⁺, P, N and P loss coefficient was higher under conventional fertilize and irrigation treatment while the loss of NO₃^- was higher under conventional fertilization and optimizing irrigation treatment. The correlations among N, P absorption by cotton, loss of NH₄⁺ and total phosphorus were quadratic function. The total nitrogen loss and cumulative nitrogen application was lineally correlated. The loss of NO₃^- and cumulative nitrogen application was exponential. The nitrogen and phosphorus absorption by cotton under conventional fertilization and optimizing irrigation treatment was 24.53% and 35.86% higher than that in conventional fertilize and irrigation treatment, respectively. The cotton yield under conventional fertilization and optimizing irrigation treatment obtained higher than that in other three treatments. Therefore, the conventional fertilization and optimizing irrigation treatment was the optimal management of water and fertilizer in our study. These results demonstrate that reasonable water, nitrogen and phosphorus fertilize could not only effectively promote the absorption of nitrogen and phosphorus, but also reduce nitrogen and phosphorus losses under drip fertigation and plastic mulching.

Transient Near-UV Absorption of the Light-Driven Sodium Pump Krokinobacter eikastus Rhodopsin 2: A Spectroscopic Marker for Retinal Configuration

We report a transient signature in the near-UV absorption of Krokinobacter eikastus rhodopsin 2 (KR2), which spans from the femtosecond up to the millisecond time scale. The signature rises with the all-trans to 13-cis isomerization of retinal and decays with the reisomerization to all-trans in the late photocycle, making it a promising marker band for retinal configuration. Hybrid quantum mechanics/molecular mechanics simulations show that the near-UV absorption signal corresponds to an S₀ → S₃ and/or an S₀ → S₅ transition, which is present in all photointermediates. These transitions exhibit a negligible spectral shift by the altering protein environment, in contrast to the main absorption band. This is rationalized by the extension of the transition densities that omits the Schiff base nitrogen. Further characterization and first steps into possible optogenetic applications were performed with near-UV quenching experiments of an induced photostationary state, yielding an ultrafast regeneration of the parent state of KR2.

Fourier Transform Infrared Spectroscopy vibrational bands study of Spinacia oleracea and Trigonella corniculata under biochar amendment in naturally contaminated soil

Fourier transform infrared spectroscopy (FTIR) spectroscopy detects functional groups such as vibrational bands like N-H, O-H, C-H, C = O (ester, amine, ketone, aldehyde), C = C, C = N (vibrational modes of a tetrapyrrole ring) and simply C = N. The FTIR of these bands is fundamental to the investigation of the effect of biochar (BC) treatment on structural changes in the chlorophyll molecules of both plants that were tested. For this, dried leaf of Spinacia oleracia (spinach) and Trigonella corniculata (fenugreek) were selected for FTIR spectral study of chlorophyll associated functional groups. The study’s primary goal was to investigate the silent features of infrared (IR) spectra of dried leave samples. The data obtained from the current study also shows that leaf chlorophyll can mask or suppress other molecules’ FITR bands, including proteins. In addition, the C = O bands with Mg and the C9 ketonic group of chlorophyll are observed as peaks at1600 (0%BC), 1650 (3%BC) and 1640, or near to1700 (5%BC) in spinach samples. In fenugreek, additional effects are observed in the FTIR spectra of chlorophyll at the major groups of C = C, C = O and C9 of the ketonic groups, and the vibrational bands are more evident at C-H and N-H of the tetrapyrrole ring. It is concluded that C-N bands are more visible in 5% BC treated spinach and fenugreek than in all other treatments. These types of spectra are useful in detecting changes or visibility of functional groups, which are very helpful in supporting biochemical data such as an increase in protein can be detected by more visibility of C-N bands in FTIR spectra.

Genetic-algorithm-assisted coherent enhancement absorption in scattering media by exploiting transmission and reflection matrices

The investigations on coherent enhancement absorption (CEA) inside scattering media are critically important in biophotonics. CEA can deliver light to the targeted position, thus enabling deep-tissue optical imaging by improving signal strength and imaging resolution. In this work, we develop a numerical framework that employs the method of finite-difference time-domain. Both the transmission and reflection matrices of scattering media with open boundaries are constructed, allowing the studies on the eigenvalues and eigenchannels. To realize CEA for scattering media with local absorption, we develop a genetic-algorithm-assisted numerical model. By minimizing the total transmittance and reflectance simultaneously, different realizations of CEA are observed and, without setting internal monitors, can be differentiated with cases of light leaked from sides. By modulating the incident wavefront at only one side of the scattering medium, it is shown that for a 5-μm-diameter absorber buried inside a scattering medium of 15 μm × 12 μm, more than half of the incident light can be delivered and absorbed at the target position. The enhancement in absorption is more than four times higher than that with random input. This value can be even higher for smaller absorption regions. We also quantify the effectiveness of the method and show that it is inversely proportional to the openness of the scattering medium. This result is potentially useful for targeted light delivery inside scattering media with local absorption.

Effects of preliminary treatment by ultrasonic and convective air drying on the properties and oil absorption of potato chips

The initial water content was closely related to the oil absorption and properties of fried food. The effects of convective air drying (D) and ultrasound combined convective air drying (UD) pretreatment on the properties and oil absorption of potato chips have been investigated. The oil contents were 48.48 ± 1.42% and 39.78 ± 3.08% for control samples (without D and UD pretreatment) and ultrasound treated samples (without D pretreatment). When the mass loss of samples was reached the proportion of quality to without drying samples quality 80%, 50%, and 20%, the oil contents of D pretreated samples decreased by 12.67%, 28.24% and 62.07%, respectively, and the oil contents of UD pretreated samples decreased by 7.42%, 24.10% and 51.76% (compared to the ultrasound pretreated samples ), respectively. By applying ultrasound before frying, more cracks and pores were exhibited of fried potato chips. After drying process, potato chips exhibited less disruption of cell structure and less deformation of cell irregular. The hardness of the D and UD pretreated potato chips increased with the extension of drying. The FTIR analysis stated the formation of amylose-lipid complexes. This research could contribute to providing evidence for the development and application of the pretreatment strategies.

Physico-Chemical Properties of Inorganic NPs Influence the Absorption Rate of Aquatic Mosses Reducing Cytotoxicity on Intestinal Epithelial Barrier Model

Noble metals nanoparticles (NPs) and metal oxide NPs are widely used in different fields of application and commercial products, exposing living organisms to their potential adverse effects. Recent evidences suggest their presence in the aquifers water and consequently in drinking water. In this work, we have carefully synthesized four types of NPs, namely, silver and gold NPs (Ag NPs and Au NPs) and silica and titanium dioxide NPs (SiO₂ NPs and TiO₂ NPs) having a similar size and negatively charged surfaces. The synthesis of Ag NPs and Au NPs was carried out by colloidal route using silver nitrate (AgNO₃) and tetrachloroauric (III) acid (HAuCl₄) while SiO₂ NPs and TiO₂ NPs were achieved by ternary microemulsion and sol-gel routes, respectively. Once the characterization of NPs was carried out in order to assess their physico-chemical properties, their impact on living cells was studied. We used the human colorectal adenocarcinoma cells (Caco-2), known as the best representative intestinal epithelial barrier model to understand the effects triggered by NPs through ingestion. Then, we moved to explore how water contamination caused by NPs can be lowered by the ability of three species of aquatic moss, namely, Leptodictyum riparium, Vesicularia ferriei, and Taxiphyllum barbieri, to absorb them. The experiments were conducted using two concentrations of NPs (100 μM and 500 Μm as metal content) and two time points (24 h and 48 h), showing a capture rate dependent on the moss species and NPs type. Then, the selected moss species, able to actively capture NPs, appear as a powerful tool capable to purify water from nanostructured materials, and then, to reduce the toxicity associated to the ingestion of contaminated drinking water.

Snapshot photoacoustic topography through an ergodic relay of optical absorption in vivo

Photoacoustic tomography (PAT) has demonstrated versatile biomedical applications, ranging from tracking single cells to monitoring whole-body dynamics of small animals and diagnosing human breast cancer. Currently, PAT has two major implementations: photoacoustic computed tomography (PACT) and photoacoustic microscopy (PAM). PACT uses a multi-element ultrasonic array for parallel detection, which is relatively complex and expensive. In contrast, PAM requires point-by-point scanning with a single-element detector, which has a limited imaging throughput. The trade-off between the system cost and throughput demands a new imaging method. To this end, we have developed photoacoustic topography through an ergodic relay (PATER). PATER can capture a wide-field image with only a single-element ultrasonic detector upon a single laser shot. This protocol describes the detailed procedures for PATER system construction, including component selection, equipment setup and system alignment. A step-by-step guide for in vivo imaging of a mouse brain is provided as an example application. Data acquisition, image reconstruction and troubleshooting procedures are also elaborated. It takes ~130 min to carry out this protocol, including ~60 min for both calibration and snapshot wide-field data acquisition using a laser with a 2-kHz pulse repetition rate. PATER offers low-cost snapshot wide-field imaging of fast dynamics, such as visualizing blood pulse wave propagation and tracking melanoma tumor cell circulation in mice in vivo. We envision that PATER will have wide biomedical applications and anticipate that the compact size of the setup will allow it to be further developed as a wearable device to monitor human vital signs.

Estimation of leaf water content from hyperspectral data of different plant species by using three new spectral absorption indices

The leaf equivalent water thickness (EWT, g cm-2) and fuel moisture content (FMC, %) are key variables in ecological and environmental monitoring. Although a variety of hyperspectral vegetation indices have been developed to estimate the leaf EWT and FMC, most of these indices are defined considered two or three specific bands for a specific plant species, which limits their applicability. In this study, we proposed three new spectral absorption indices (SAI970, SAI1200, and SAI1660) for various plant types by considering the symmetry of the spectral absorption at 970 nm, 1200 nm and 1660 nm and spectral heterogeneity of different leaves. The indices were calculated considering the absorption peak and shoulder bands of each leaf instead of the same specific bands for all leaves. A pooled dataset of three tree species (camphor (VX), capricorn (VJ), and red-leaf plum (VL)) was used to test the performance of the SAIs in terms of the leaf EWT and FMC estimation. The results indicated that, first, SAI1200 was more suitable for estimating the EWT than FMC, whereas SAI970 and SAI1660 were more suitable for estimating the FMC. Second, SAI1200 achieved the most accurate estimation of the EWT with a cross-validation coefficient of determination (Rcv2) of 0.845 and relative cross-validation root mean square error (rRMSEcv) of 8.90%. Third, SAI1660 outperformed the other indices in estimating the FMC at the leaf level, with an Rcv2 of 0.637 and rRMSEcv of 8.56%. Fourth, SAI970 achieved a moderate accuracy in estimating the EWT (Rcv2 of 0.25 and rRMSEcv of 19.68%) and FMC (Rcv2 of 0.275 and rRMSEcv of 12.10%) at the leaf level. These results can enrich the application of the SAIs and demonstrate the potential of using SAI1200 to determine the leaf EWT and SAI1660 to obtain the leaf FMC among various plant types.

Biosorbent with superhydrophobicity and superoleophilicity for spilled oil removal

The development of efficient and sustainable sorbents for emergent oil cleanup has attracted tremendous attention. In this study, the feasibility of enzymatic grafting of octadecylamine (ODA) on corn stalk pith (CSP) by laccase-TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) treatment for enhanced oil-water separation was investigated. The dynamic contact angle tests suggest that the modified CSP (LCSP) had higher hydrophobicity (WCA, 157.2˚) and lipophilicity (OCA, 0˚) than the CSP did. In addition, the introduction of ODA onto the surface of modified CSP was verified by a variety of characterization techniques including SEM, FT-IR, and XPS. Compared with the control, laccase-TEMPO treatment of CSP coupled with octadecylamine grafting greatly improved the oil sorption capacity from 13.24 g/g to 44.25 g/g, while substantially reduced the water sorption capacity from 15.52 g/g to 2.76 g/g. LCSP has fast kinetic (sorption equilibrium reached before 60 min) and high fits to the pseudo-second-order kinetic model. The results obtained in this study reveal the feasibility of using Laccase-TEMPO treatment to graft the ODA onto the surface of CSP, thereby enhancing the rate and capacity of oil separation from oily water. The method and sorbent developed in this study hold promise for green, simple and cost-effective oil cleanup during oil spillage emergency events.

Cell-by-cell estimation of PAH sorption and subsequent toxicity in marine phytoplankton

Polycyclic Aromatic Hydrocarbons (PAHs) have elicited increasing concern due to their ubiquitous occurrence in coastal marine environments and resultant toxicity in organisms. Due to their lipophilic nature, PAHs tend to accumulate in phytoplankton cells and thus subsequently transfer to other compartments of the marine ecosystem. The intrinsic fluorescence properties of PAHs in the ultraviolet (UV)/blue spectral range have recently been exploited to investigate their uptake modes, localization, and aggregation in various biological tissues. Here, we quantitatively evaluate the sorption of two model PAHs (phenanthrene and pyrene) in three marine phytoplankton species (Chaetoceros tenuissimus, Thalassiosira sp. and Proteomonas sp.) using a combined approach of UV excitation flow cytometry and fluorescence microscopy. Over a 48-h exposure to a gradient of PAHs, Thalassiosira sp. showed the highest proportion of PAH-sorbed cells (29% and 97% of total abundance for phenanthrene and pyrene, respectively), which may be attributed to its relatively high total lipid content (33.87 percent dry weight). Moreover, cell-specific pulse amplitude modulation (PAM) microscope fluorometry revealed that PAH sorption significantly reduced the photosynthetic quantum efficiency (F_v/F_m) of individual phytoplankton cells. We describe a rapid and precise hybrid method for the detection of sorption of PAHs on phytoplankton cells. Our results emphasize the ecologically relevant sub-lethal effects of PAHs in phytoplankton at the cellular level, even at concentrations where no growth inhibition was apparent. This work is the first study to address the cell-specific impacts of fluorescent toxicants in a more relevant toxicant-sorbed subpopulation; these cell-specific impacts have to date been unidentified in traditional population-based phytoplankton toxicity assays.

Sonication increases the porosity of uncooked rice kernels affording softer textural properties, loss of intrinsic nutrients and increased uptake capacity during fortification

This work investigates the effect of sonication on brown and milled rice grains of both waxy and non-waxy varieties. We report herein the microstructural analysis of uncooked rice kernels under sonication and its effect on the textural properties. X-ray computed tomography results showed the formation of microporous surfaces and the creation of cracks and fissures. Sonication increased the % porosity of the rice samples allowing for easy penetration of water during the cooking process and promotes softer texture. Moreover, the effect of sonication in brown rice resulted to the decrease in endogenous iron and phosphorus contents but increased its capacity for iron uptake through fortification when sonicated rice is soaked in the mineral solution.

Characterization of wastewater effluent organic matter with different solid phase extraction sorbents

Effluent organic matter (EfOM) from municipal wastewater treatment plants (WWTPs) has received increasing attention due to its impacts on natural and engineered aquatic systems. A comprehensive understanding of molecular compositions of EfOM is crucial for controlling its negative effects and effective removal of it. Fourier transform-ion cyclotron resonance mass spectrometry (FTICR MS) is a powerful method to characterize molecular compositions of EfOM. However, application of this powerful technique is very depending on the sample preparation procedures (i.e. solid phase extraction, SPE) for enrichment and desalting. In this study, a systematic comparison of the difference in molecular compositions of the EfOM extracted using eighteen different SPE sorbents (Envicarb, PPL, ENV, HLB, C18, C18OH, C8, PH, CH, WAX, WCX, MAX, MCX, CBA, C2, CN-E, NH2, and SI) was investigated. Molecular characterization using FTICR MS showed that non-polar sorbents (Envicarb, PPL, ENV, HLB, C18, C18OH) and mixed mode sorbents (WAX, WCX, MAX, MCX) prefer to extract more aromatic and unsaturated molecules, while strongly-polar (SI), mid-polar (CBA, NH2), and weakly non-polar (C2, CN-E) sorbents prefer to extract more aliphatic components. In addition, it is found that combining extracts of CBA, ENV, and EnviCarb sorbents might be a practical way to provide a comprehensive information of molecular composition of EfOM. The results reported in this study provide valuable information on molecular compositions of EfOM and the selectivity of EfOM by different SPE sorbents.

Polyethylene glycol-based deep eutectic solvents as a novel agent for natural gas sweetening

Deep eutectic solvents (DESs) have received significant attention as potential extracting agents in recent years due to their favorable characteristics including low cost, easy preparation and environmentally safe starting materials. Experimentally screening for highly efficient DESs meeting various requirements for natural gas sweetening remains a challenging task. Thus, an extensive database of estimated Henry’s law constants (H_i) and solubilities (x_i) of CO₂ in 170 different DESs at 25°C has been constructed using the COSMO-RS method to select potential DESs. Based on the COSMO-RS study, three DESs, namely tetrabutylammonium bromide (TBAB)+polyethylene glycol (PEG-8) (on a molar basis 1:4), TBAB+octanoic acid (OCT) (1:4), and methyltriphenylphosphonium bromide (MTPB)+PEG-8 (1:10), were chosen for further experimentation up to 2 bar at 25°C using a vapor-liquid equilibria (VLE) apparatus. Reliable thermophysical properties were determined experimentally, and a detailed equilibrium-based model was developed for one of the glycol-based DESs (i.e., TBAB+PEG-8 (1:4)). This information is an essential prerequisite for carrying out process simulations of natural gas sweetening plants using ASPEN PLUS. The simulation results for the proposed DES were compared to those of monoethylene glycol (MEG). Here, we find that the aqueous TBAB+PEG-8 (1:4) solvent shows ~60% lower total energy consumption and higher CO₂ removal when compared to those using the MEG solvent.

NIR Absorbing AzaBODIPY Dyes for pH Sensing

Two near-infrared (NIR) absorbing di(thien-2-nyl)-di(dimethylanilino)azaBODIPY dyes 2a and 2b were synthesized and characterized that differ depending on whether the dimethylaniline substituents are introduced at the 3,5- or 1,7-positions of the azaBODIPY core. The main spectral bands lie at 824 and 790 nm, respectively, in CH₂Cl₂. The effect of substituent position on the photophysical and pH sensing properties was analyzed through a comparison of the optical properties with the results of time-dependent density functional theory (TD-DFT) calculations. Protonation of the dimethylamino nitrogen atoms eliminates the intramolecular charge transfer properties of these compounds, and this results in a marked blue-shift of the main absorption bands to 696 and 730 nm, respectively, in CH₂Cl₂, and a fluorescence “turn-on” effect in the NIR region. The pH dependence studies reveal that the pK_a values of the non-protonated 2a and 2b molecules are ca. 6.9 (±0.05) and 7.3 (±0.05), respectively, while that of the monoprotonated species for both dyes is ca. 1.4 (±0.05) making them potentially suitable for use as colorimetric pH indicators under highly acidic conditions.

Challenging a Preconception: Optoacoustic Spectrum Differs from the Optical Absorption Spectrum of Proteins and Dyes for Molecular Imaging

Optoacoustic (photoacoustic) imaging has seen marked advances in detection and data analysis, but there is less progress in understanding the photophysics of common optoacoustic contrast agents. This gap blocks the development of novel agents and the accurate analysis and interpretation of multispectral optoacoustic images. To close it, we developed a multimodal laser spectrometer (MLS) to enable the simultaneous measurement of optoacoustic, absorbance, and fluorescence spectra. Herein, we employ MLS to analyze contrast agents (methylene blue, rhodamine 800, Alexa Fluor 750, IRDye 800CW, and indocyanine green) and proteins (sfGFP, mCherry, mKate, HcRed, iRFP720, and smURFP). We found that the optical absorption spectrum does not correlate with the optoacoustic spectrum for the majority of the analytes. We determined that for dyes, the transition underlying an aggregation state has more optoacoustic signal generation efficiency than the monomer transition. For proteins we found a favored optoacoustic relaxation that stems from the neutral or zwitterionic chromophores and unreported photoswitching behavior of tdTomato and HcRed. We then crystalized HcRed in its photoswitch optoacoustic state, confirming structurally the change in isomerization with respect to HcReds' fluorescence state. Finally, on the example of the widely used label tdTomato and the dye indocyanine green, we show the importance of correct photophysical (e.g., spectral and kinetic) information as a prerequisite for spectral-unmixing for in vivo imaging.

Chlorophyll absorption and phytoplankton size information inferred from hyperspectral particulate beam attenuation

Electromagnetic theory predicts spectral dependencies in extinction efficiency near a narrow absorption band for a particle with an index of refraction close to that of the medium in which it is immersed. These absorption band effects are anticipated in oceanographic beam-attenuation (beam-c) spectra, primarily due to the narrow red peak in absorption produced by the phytoplankton photopigment, chlorophyll a (Chl a). Here we present a method to obtain Chl a absorption and size information by analyzing an eigendecomposition of hyperspectral beam-c residuals measured in marine surface waters by an automatic underway system. We find that three principal modes capture more than 99% of the variance in beam-c residuals at wavelengths near the Chl a red absorption peak. The spectral shapes of the eigenvectors resemble extinction efficiency residuals attributed to the absorption band effects. Projection of the eigenvectors onto the beam-c residuals produces a time series of amplitude functions with absolute values that are strongly correlated to concurrent Chl a absorption line height (a_LH) measurements (r values of 0.59 to 0.83) and hence provide a method to estimate Chl a absorption. Multiple linear regression of a_LH on the amplitude functions enables an independent estimate of a_LH, with RMSE of 3.19⋅10^-3m^-1 (3.3%) or log₁₀-RMSE of 18.6%, and a raw-scale R² value of 0.90 based on the Tara Oceans Expedition data. Relationships between the amplitude functions and the beam-c exponential slopes are in agreement with theory relating beam-c to the particle size distribution. Compared to multispectral analysis of beam-c slope, hyperspectral analysis of absorption band effects is anticipated to be relatively insensitive to the addition of nonpigmented particles and to monodispersion.

Assessing the Aflatoxins Mitigation Efficacy of Blueberry Pomace Biosorbent in Buffer, Gastrointestinal Fluids and Model Wine

Blueberry (BB) and cherry pomace were investigated as new biosorbents for aflatoxins (AFs) sequestration from buffered solutions, gastrointestinal fluids and model wine. Among the tested biosorbents, BB exhibited the maximum adsorption performance for AFs and hence was further selected for the optimization of experimental parameters like pH, dosage, time and initial concentration of AFs. Material characterizations via scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, N2 adsorption-desorption isothermal studies, thermogravimetric analysis (TGA) and X-ray photon spectroscopy (XPS) techniques revealed useful information about the texture and chemical composition of the biosorbents. The fitting of isothermal data with different models showed the model suitability trend as: Sips model > Langmuir model > Freundlich model, where the theoretical maximum adsorption capacity calculated from the Sips model was 4.6, 2.9, 2.7 and 2.4 mg/g for AFB1, AFB2, AFG1 and AFG2, respectively. Kinetics study revealed the fast AFs uptake by BB (50-90 min) while thermodynamics studies suggested the exothermic nature of the AFs adsorption from both, single as well as multi-toxin buffer systems, gastrointestinal fluids and model wine. Accrediting to the fast and efficient adsorption performance, green and facile fabrication approach and cost-effectiveness, the newly designed BB pomace can be counted as a promising contender for the sequestration of AFs and other organic pollutants.

In vivo time-domain diffuse correlation spectroscopy above the water absorption peak

Time-domain diffuse correlation spectroscopy (TD-DCS) is a newly emerging optical technique that exploits pulsed, yet coherent light to non-invasively resolve the blood flow in depth. In this work, we have explored TD-DCS at longer wavelengths compared to those previously used in literature (i.e., 750-850 nm). The measurements were performed using a custom-made titanium-sapphire mode-locked laser, operating at 1000 nm, and an InGaAs photomultiplier as a detector. Tissue-mimicking phantoms and in vivo measurements during arterial arm cuff occlusion in n=4 adult volunteers were performed to demonstrate the proof of concept. We obtained a good signal-to-noise ratio, following the hemodynamics continuously with a relatively fast (1 Hz) sampling rate. In all the experiments, the auto-correlation functions show a decay rate approximately five-fold slower compared to shorter wavelengths. This work demonstrates the feasibility of in vivo TD-DCS in this spectral region and its potentiality for biomedical applications.

Grafting polysiloxane onto ultrafiltration membranes to optimize surface energy and mitigate fouling

Conventional approaches to mitigate fouling of membrane surfaces impart hydrophilicity to the membrane surface, which increases the water of hydration and fluidity near the surface. By contrast, we demonstrate here that tuning the membrane surface energy close to that of the dispersive component of water surface tension (21.8 mN m^-1) can also improve the antifouling properties of the membrane. Specifically, ultrafiltration (UF) membranes were first modified using polydopamine (PDA) followed by grafting of amine-terminated polysiloxane (PSi-NH₂). For example, with 2 g L^-1 PSi-NH₂ coating solution, the obtained coating layer contains 53% by mass fraction PSi-NH₂ and exhibits a total surface energy of 21 mN m^-1, decreasing the adsorption of bovine serum albumin by 44% compared to the unmodified membrane. When challenged with 1 g L^-1 sodium alginate in a constant-flux crossflow system, the PSi-NH₂-grafted membrane exhibits a 70% lower fouling rate than the pristine membrane at a water flux of 110 L (m² h)^-1 and good stability when cleaned with NaOH solutions.

Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks

The emergence of a pandemic affecting the respiratory system can result in a significant demand for face masks. This includes the use of cloth masks by large sections of the public, as can be seen during the current global spread of COVID-19. However, there is limited knowledge available on the performance of various commonly available fabrics used in cloth masks. Importantly, there is a need to evaluate filtration efficiencies as a function of aerosol particulate sizes in the 10 nm to 10 μm range, which is particularly relevant for respiratory virus transmission. We have carried out these studies for several common fabrics including cotton, silk, chiffon, flannel, various synthetics, and their combinations. Although the filtration efficiencies for various fabrics when a single layer was used ranged from 5 to 80% and 5 to 95% for particle sizes of <300 nm and >300 nm, respectively, the efficiencies improved when multiple layers were used and when using a specific combination of different fabrics. Filtration efficiencies of the hybrids (such as cotton-silk, cotton-chiffon, cotton-flannel) was >80% (for particles <300 nm) and >90% (for particles >300 nm). We speculate that the enhanced performance of the hybrids is likely due to the combined effect of mechanical and electrostatic-based filtration. Cotton, the most widely used material for cloth masks performs better at higher weave densities (i.e., thread count) and can make a significant difference in filtration efficiencies. Our studies also imply that gaps (as caused by an improper fit of the mask) can result in over a 60% decrease in the filtration efficiency, implying the need for future cloth mask design studies to take into account issues of "fit" and leakage, while allowing the exhaled air to vent efficiently. Overall, we find that combinations of various commonly available fabrics used in cloth masks can potentially provide significant protection against the transmission of aerosol particles.

Novel approach towards the synthesis of highly efficient flame retardant electrode and oil/organic solvent absorber

We have developed a facile one pot process to synthesize an ultra-light functionalized spongy graphene (FSG). This is the first approach to use carbon based flame retardant spongy material as an electrode to build completely flame retardant supercapacitor (FRS) also as an oil/organic solvent absorber. The fully FRS concept has created by the compilation of as-prepared FSG with flame retardant separator and electrolyte. As-prepared FSG contained high amount of phosphorus and nitrogen functional groups, which makes it potent flame retardant electrochemical material, to use it as an efficient FR electrode. Flame test of FSG revealed that it doesn't catch fire for ∼1500 s. Also, FSG was able to sustain flame retardancy at a temperature as high as 1500 °C for continuous exposure of ∼300 s. FSG used as an electrode for symmetric capacitor possessing maximum specific capacitance of 494.3 F g^-1 at a current density 1 A g^-1. Corresponding high energy density and power density values are 55.6 Wh kg^-1 and 1799 W kg^-1. It shows cycling stability of 86.1% after 5000 cycles at current density of 10 A g^-1. The electrochemical property of FSG was also confirmed using three electrode system. Flame retardant FSG material was also used for the absorption and recovery of oil and organic solvents. FSG has high oil and organic solvent sorption capacity in the range of 40-70 g/g, also can be reused for minimum 10 cycles. Such approach has great significance for multifunctional graphene based nanocomposites will open the new window for large-scale applications.

Enhancing terahertz molecular fingerprint detection by a dielectric metagrating

Terahertz (THz) sensing of molecular fingerprint enables wide applications in biomedicine and security detection. Conventional detection approaches face big barriers in trace analysis of analyte due to the difficulties of enhancing the broadband molecular absorption. In order to achieve strong broadband wave-matter interaction for the analyte, we propose a method based on THz wave angular scanning on a dielectric metagrating. In virtue of the guided-mode resonance, one can strengthen the local electric field in various trace-amount analytes by tuning the polarization and incident angle, which leads to significant enhancement on the broadband signal of molecular fingerprint. The study paves the way for more applications of THz trace-amount detection.

Indocyanine green provides absorption and spectral contrast for optical coherence tomography at 840 nm in vivo

In recent years, there has been growing interest in the application of exogenous contrast agents to supplement the traditional strengths of optical coherence tomography (OCT) and provide additional biological information. In this Letter, we present how indocyanine green, a common fluorescent contrast agent approved by the United States Food and Drug Administration, can provide absorption and spectral contrast for OCT imaging in the mouse eye in vivo. We further demonstrate high stability of spectral contrast measurements for the long-term monitoring of contrast agents in spite of fluctuations in intensity.

Facile fabrication of wood-inspired aerogel from chitosan for efficient removal of oil from Water

Aerogels that derived from biomass have long been attractive as absorbents for oil clean-up. However, it remains a significant challenge to prepare fully bio-based oil absorbents that combines fast oil/water separation capacity, adequate mechanical robustness and easy recyclability through green and facile strategy. Inspired by the fascinating structure of wood, here we report a highly porous and anisotropic bio-based aerogel by taking advantage of the directional freezing technology, followed by a freeze-drying and silylation process. Due to the directional growth of ice crystals along the vertical direction, a special spring like morphology was obtained, which is mainly composed of well aligned low-tortuosity channels that seamlessly connected to bottom layer. Superior mechanical properties that allow for high mechanical compressing and fast elastic recovery were consequently acquired. Moreover, the silylated CS aerogel displays a rather high oil absorption capacity of 63 g g^-1, together with excellent recyclability via simple hand squeezing. By virtue of such hierarchical morphology, a device that could continuously separate oil from water was successfully designed. Given the natural abundance of raw material as well as the easy processability, this work would lay solid foundation for further fabrication of bio-based oil absorbents toward low-cost, high-performance and large-scale commodities.

Optical coherence tomography modeling incorporating scattering, absorption, and multiple reflections

A direct scattering optical coherence tomography forward model was developed to simulate A-scans for both idealized and real light sources on an arbitrary given sample structure. Previous models neglected absorption, scattering, and multiple reflections at interfacial layers, and so two extended models were developed to investigate the impact of these processes. The first model uses the Beer-Lambert law to incorporate both absorption and scattering optical processes, and the second model uses a recursive form to model multiple reflections. These models were tested on a structure representative of a multilayered skin sample. The results show that the absorption and scattering processes have significant impact on the height of the peaks in the simulated A-scans. Conversely, the incorporation of multiple reflections has very little impact on the height of these peaks. Neither of the above processes has any impact on the locations of the A-scan peaks, which are associated with the sample interfaces between layers.

Using optical fibers to measure absorption in intact conifer leaves, relative numbers of chloroplasts, and pigment content

For investigations of ongoing processes in plants, such as photosynthesis in conifer leaves, nondestructive and noninvasive measuring techniques are needed. In this paper, a novel approach has been developed for the measurement of chloroplasts' numbers and pigment contents in conifer leaves based on the measurements of leaf absorption spectra using optical fibers and an array spectrophotometer. To eliminate the effect of scattering on the measured absorption spectra, a strategy has been applied taking advantage of the combined use of thin optical fibers normal to the needle's longitudinal axis and the phenomenon that scattering is largest in the forward direction. The optical path in the leaf is nearly the distance between the fiber tips; thus, we were able to obtain the absorption spectrum of the pigments in situ. A effect of the measured absorption spectra, occurring due to the organization of pigments in the leaf and interaction between light and leaf interior, can be accounted for by using the so-called Duysens transformation. Using this transformation, pigment contents and the relative number of chloroplasts can be obtained from the measured absorption spectra. We applied the method to observe pigment concentrations in different stages of the greening process in the leaves of two conifer species, Taxus baccata and Picea abies. The presented method may be used to estimate changes in chloroplast number and pigment content during various phases of greening of a species and to observe differences among various species.

Nanoplatforms with Remarkably Enhanced Absorption in the Second Biological Window for Effective Tumor Thermoradiotherapy

Thermoradiotherapy acts as an important antitumor modality because heating can increase the blood flow and improve the oxygen level in tumor, thus remission of hypoxia-associated resistance for radiotherapy (RT). However, most agents for thermoradiotherapy are used either in the first near-infrared biological window or low photothermal conversion efficiency. Here, a facile method to prepare Cu_xS/Au nanocomposites via reduction methods from Cu_xS templates in mild synthetic conditions (i.e., aqueous solution and room temperature) is presented. After the growth of Au nanoparticles, the Cu_xS/Au nanocomposites have greater benefits for photothermal efficiency than that of Cu_xS nanoparticles due to the enhanced absorbance in the second near-infrared window. Moreover, biocompatibility and stability of these nanocomposites are greatly improved by lipoic acid poly(ethylene glycol). After the tumors were irradiated with a 1064 nm laser, their oxygenation status is subsequently improved, and the combination of photothermal therapy and RT achieves remarkable synergistic therapeutic effects. This work provides a novel idea to design a new-generation nanomedicine for tumor thermoradiotherapy.

Baltic Fucus vesiculosus as potential bio-sorbent for Zn removal: Mechanism insight

This research aimed to find the best phenotype of the brown algae Fucus vesiculosus (kelp) which has the greater potential to become a sorption byproduct for Zn removal from contaminated waters. Thus, the Zn uptake capacity and sorption mechanisms of the kelp collected from the Baltic Sea shore was, for the first time, investigated under various conditions, and compared to the phenotype habiting on the Irish Sea shore. Sorption studies were performed investigating the effect of algal dosage, Zn sources as well as algal harvesting time of the year on Zn uptake capacity. The results suggested that the Baltic algae is a better bio-sorbent for Zn uptake. Sorption mechanisms were studied by employing various indirect and direct approaches, more importantly, including high resolution synchrotron X-Ray Fluorescence and X-Ray Absorption Spectroscopy (XAS) and molecular modelling (MM). The results revealed that alginate and cellulose are among the main polysaccharide bonding Zn at algal surface, via coordination with O atoms from carboxyl and hydroxyl groups. XAS results giving direct measurements of Zn bonding environment on algal surface are supported by MM outputs and suggested that Zn is surrounded by ca. 5 O atoms at interatomic distances varying from 1.94 to 2.02 Å. The results contribute to understanding sorption mechanisms which can further lead to finding the best eluent for Zn desorption from the used biomass, bio sorbent reconditioning and reuse in multiple sorption desorption cycles as well as process optimization before industrial scaling up.

Guanidinocalix[5]arene for sensitive fluorescence detection and magnetic removal of perfluorinated pollutants

Perfluorinated alkyl substances, such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are toxic materials that are known to globally contaminate water, air, and soil resources. Strategies for the simultaneous detection and removal of these compounds are desired to address this emerging health and environmental issue. Herein, we develop a type of guanidinocalix[5]arene that can selectively and strongly bind to PFOS and PFOA, which we use to demonstrate the sensitive and quantitative detection of these compounds in contaminated water through a fluorescent indicator displacement assay. Moreover, by co-assembling iron oxide nanoparticle with the amphiphilic guanidinocalix[5]arene, we are able to use simple magnetic absorption and filtration to efficiently remove PFOS and PFOA from contaminated water. This supramolecular approach that uses both molecular recognition and self-assembly of macrocyclic amphiphiles is promising for the detection and remediation of water pollution.

Prompting medical students to self-assess their learning needs during the ageing and health module: a mixed methods study

Understanding our learning needs is fundamental for safe, effective and knowledge-based medical practice and facilitates life-long learning. A mixed methods study investigated fourth-year medical students' self-perceived understanding of their learning needs using 1] a visual scale, before and after a four-week module in Ageing and Health (A&H) and 2] through focus group discussions. During 2013-14 academic year, all students (252) were invited to use a Visual Analogue Scale (VAS) tool to self-assess their learning needs that were linked to Ageing and Health curriculum learning outcomes. Assenting students (197 at pre-self-assessment, 201 at post-assessment) returned anonymous Visual Analogue Scales, self-assessing history-taking skills, examination skills, knowledge of medication use, co-morbidity, nutritional and swallowing assessment responses, before and after the A&H module. Three student focus groups explored whether completion of the VAS self-assessment had prompted improved self-awareness of their learning needs. The VAS responses increased for each curriculum domain with significant differences between the pre-and post responses - for the student-year-group. Nutritional and swallowing knowledge showed the greatest improvement from a self-assessed low baseline at entry. Focus-group students generally viewed the VAS tool positively, and as an aid for prompting consideration of current and future clinical practice. Some students recognised that 'a need to be ready-for-work' focused engaged learning; others demonstrated self-regulated learning through self-motivation and an action plan. The Visual Analogue Scale quantitative responses showed increased student-self-perceived learning for each curriculum domain at fourth-year completion of the A&H module, suggesting that prompting self-assessment had increased students' knowledge and skills. Focus group students saw the VAS tool as useful for prompting awareness of their current and future learning needs. Additional educational strategies should be explored to enable all students to self-reflect and engage effectively on their learning needs, to gain the skills for the maintenance of professional medical competence. Abbreviations: A&H: Ageing and Health Module; e-portfolio: an electronic version of an evidence portfolio, which allows medical students and graduates to reflect and document learning and competencies; F1: year1 of post-graduate medical clinical training; GMC: General Medical Council-the regulation organisation for maintaining standards for doctors in UK; Logbook: usually a written document which can be used to record procedures and attendance at clinics or case-based discussions and can be used to set learning outcomes and to structure teaching in clinical settings for medical students and doctors; PDP: personal development plan is used to plan future learning and skills needs for work and education with an plan for action/s outcome; SPSS: Statistical Package for the Social Sciences; VAS: Visual Analogue Scale is a visual method of describing an experience.

Determination of optical parameters of the porcine eye and development of a simulated model

The eye is a very sophisticated system of optical elements for the preeminent sense of vision. In recent years, the number of laser surgery to correct the optical aberration such as myopia or astigmatism has significantly increased. Consequently, improving the knowledge related to the interactions of light with the eye is very important in order to enhance the efficiency of the surgery. For this reason, a complete optical characterization of the porcine eye is presented in this study. Kubelka-Munk and Inverse Adding-Doubling methods were applied to spectroscopy measurement to determine the absorption and scattering coefficients. Furthermore, the refractive index has been measured by ellipsometry. The different parameters were obtained for the cornea, lens, vitreous humor, sclera, iris, choroids and eyelid in the visible and infrared region. Thereafter, the results are implemented in a COMSOL Multiphysics® software to create an eye model. This model gives a better understanding of the propagation of light in the eye by adding optical parts such as the iris, the sclera or the ciliary bodies. Two simulations show the propagation of light from the cornea to the retina but also from the sclera to the retina. This last possibility provides a better understanding of light propagation during eye laser surgery such as, for example, transscleral cyclophotocoagulation. Figure: Eye simulation models allow the development of new laser treatments in a simple and safe way for patients. To this purpose, the creation of an eye simulated model based on optical parameters obtained from experimental data is presented in this study. This model will facilitate the understanding of the light propagation inside the porcine eye.

The retrograde adsorption phenomenon at the onset of breakthrough and its quantitation: An experimental case study for gaseous toluene on activated carbon surface

The adsorption dynamics of common solid sorbents against various pollutant species are yet poorly understood with respect to the retrograde phenomenon in which the relationship between breakthrough vs. pulled volume is characterized by an early unusual trend (initial increase followed by a decrease to a minimum) and by a normal trend of finally increasing to 100% (or equilibrium). If such trend is expressed in terms of the partition coefficient (PC), a reversed trend of adsorption processes becomes more evident. Retrograde has been previously observed in the initial breakthrough (<10%) isotherms in continuous flow gas-phase adsorption processes. However, retrograde has been neglected/overlooked and not discussed at all in the main stream literature even when it is explicitly observed from isotherm datasets. To properly describe the various aspects of such process, a stop-flow technique was developed to measure the adsorption isotherm of a model volatile organic compound (i.e., toluene in this study) onto a commercial low-cost sorbent (activated carbon: AC). Accordingly, a 10% breakthrough volume of 762 L atm g^-1 (corresponding adsorption capacity of 142 mg g^-1) was determined (at an inlet stream 5 Pa of toluene in 1 atm of N₂ and 5 mg of AC). This automated method was effective to generate a detailed breakthrough profile at high stream-flow rates (or high space velocities) to specifically detect the retrograde phenomenon at the breakthrough onset. This study offers a practical approach towards establishing an in-depth monitoring protocol for the rare retrograde phenomenon.

Plasmonic Pt Superstructures with Boosted Near-Infrared Absorption and Photothermal Conversion Efficiency in the Second Biowindow for Cancer Therapy

Photothermal therapy triggered by near-infrared light in the second biowindow (NIR-II) has attracted extensive interest owing to its deeper penetration depth of biological tissue, lower photon scattering, and higher maximum permissible exposure. In spite of noble metals showing great potential as the photothermal agents due to the tunable localized surface plasmon resonance, the biological applications of platinum are rarely explored. Herein, a monocomponent hollow Pt nanoframe ("Pt Spirals"), whose superstructure is assembled with three levels (3D frame, 2D layered shells, and 1D nanowires), is reported. Pt Spirals exhibit outstanding photothermal conversion efficiency (52.5%) and molar extinction coefficients (228.7 m² mol^-1 ) in NIR-II, which are much higher than those of solid Pt cubes. Simulations indicate that the unique superstructure can be a significant cause for improving both adsorption and the photothermal effect simultaneously in NIR-II. The excellent photothermal effect is achieved and subsequently verified in in vitro and in vivo experiments, along with superb heat-resistance properties, excellent photostability, and a prominent effect on computed tomography (CT) imaging, demonstrating that Pt Spirals are promising as effective theranostic platforms for CT imaging-guided photothermal therapy.

Chemical synthesis of 7α-hydroxycholest-4-en-3-one, a biomarker for irritable bowel syndrome and bile acid malabsorption

7α-Hydroxy-cholest-4-en-3-one is a biomarker for bile acid loss, irritable bowel syndrome, and other diseases associated with defective bile acid biosynthesis. Furthermore, 7α-hydroxy-cholest-4-en-3-one is the physiological substrate for cytochrome P450 8B1 (P450 8B1 or CYP8B1), the oxysterol 12α-hydroxylase enzyme implicated in obesity and cardiovascular health. We report the chemical synthesis of this physiologically important oxysterol beginning with cholesterol. The key feature of this synthesis involves a regioselective C3-allylic oxidation of a 3-desoxy-Δ⁴-7α-formate steroid precursor to form 7α-formyloxy-cholest-4-en-3-one, which was saponified to yield 7α-hydroxy-cholest-4-en-3-one.

Salinity modifies heavy metals and arsenic absorption by the halophyte plant species Kosteletzkya pentacarpos and pollutant leaching from a polycontaminated substrate

Phytomanagement of polycontaminated soils is challenging, especially in areas simultaneously affected by salinity. The wetland halophyte plant species Kosteletzkya pentacarpos was cultivated in a column device allowing leachate harvest, on a polycontaminated spiked soil containing Cd (6.5 mg kg^-1 DW), As (75 mg kg^-1 DW), Zn (200 mg kg^-1 DW) and Pb (300 mg kg^-1 DW) and irrigated with salt water (final soil electrical conductivity 5.0 ms cm^-1). Salinity increased Cd bioavailability in the soil and Cd accumulation in the shoots while it had an opposite effect on As. Salinity did not modify Pb and Zn bioavailability and accumulation. Cultivating plants on the polluted soil drastically reduced the volume of leachate. In all cases, salinity reduced the total amounts of heavy metals removed by the leachate and significantly increased the proportion of Cd and Zn removed by the plants. Heavy metal contamination induced a decrease in shoot dry weight and an increase in malondialdehyde (an indicator of oxidative stress); both symptoms were alleviated by the additional presence of NaCl but this positive impact was not related to increase in protecting phytochelatins synthesis. It is concluded i) that bioavailability estimated by the 0.01M CaCl₂ extraction procedure is not fully relevant from the heavy metal mobility, ii) that salinity decreased heavy metal percolation, especially in soils cultivated with K. pentacarpos and iii) that salinity improves plant tolerance to heavy metals in K. pentacarpos and that this species is a promising plant material for phytoremediation of polycontaminated soils.

Surfactant-Stripped Micelles for NIR-II Photoacoustic Imaging through 12 cm of Breast Tissue and Whole Human Breasts

Surfactant-stripped micelles are formed from a commercially available cyanine fluoroalkylphosphate (CyFaP) salt dye and used for high contrast photoacoustic imaging (PAI) in the second near-infrared window (NIR-II). The co-loading of Coenzyme Q10 into surfactant-stripped CyFaP (ss-CyFaP) micelles improves yield, storage stability, and results in a peak absorption wavelength in the NIR-II window close to the 1064 nm output of Nd-YAG lasers used for PAI. Aqueous ss-CyFaP dispersions exhibit intense NIR-II optical absorption, calculated to be greater than 500 at 1064 nm. ss-CyFaP is detected through 12 cm of chicken breast tissue with PAI. In preclinical animal models, ss-CyFaP is visualized in draining lymph nodes of rats through 3.1 cm of overlaid chicken breast tissue. Following intravenous administration, ss-CyFaP accumulates in neoplastic tissues of mice and rats bearing orthotopic mammary tumors without observation of acute toxic side effects. ss-CyFaP is imaged through whole compressed human breasts in three female volunteers at depths of 2.6-5.1 cm. Taken together, these data show that ss-CyFaP is an accessible contrast agent for deep tissue PAI in the NIR-II window.

Enhancement of biocompatibility and carbohydrate absorption control potential of rosmarinic acid through crosslinking into microparticles

Rosmarinic acid (RA), a bioflavonoid and antioxidant that exists in plants of the Lamiaceae family, was crosslinked into particles as poly(Rosmarinic Acid) (p(RA)) via an emulsion crosslinking method. The particles were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, solid state nuclear magnetic resonance 13C NMR spectroscopy, and thermal gravimetric analysis. The zeta potential values of p(RA) particles were determined at different pHs; the isoelectric point was estimated as pH 1.2. The release of monomeric RA from the particles at 37.5 °C was found to be similar at different pHs, 1.0, 7.4, and 11.0. The effects of p(RA) on hemolysis and coagulation were found to be minimal. The antioxidant activity of p(RA) particles and RA monomer were almost indistinguishable suggesting that p(RA) particles may be used as an antioxidant. On a per weight basis, p(RA) particles were ~66% less cytotoxic to mammalian cells that RA monomer, as assessed using COS-1 cells. In addition, p(RA) was an 8.6-fold stronger inhibitor of α-glycosidase than RA; the IC50s of the monomer and particles were 0.121 and 0.014 mg/mL, respectively. The strong inhibitory effect of p(RA) on α-glycosidase, coupled with its reduced cytotoxicity and antioxidant activity, provide new opportunities for the use of p(RA).

Development of starch nanoparticles based composite films from non-conventional source - Water chestnut (Trapa bispinosa)

In the present study, starch was isolated from a non-conventional source (water chestnut) and various physicochemical properties were investigated. Nano starch was prepared by adopting the acid hydrolysis method having a yield of 27.5%. Particle size distribution of native and nano starch was 5559 nm and 396 nm. The unique feature of water chestnut starch was the shape of starch granule that looked oval, ellipsoidal, mixed with spherical granules without cracks and smooth surface. While the water chestnut nano starch appeared as an agglomerated form with irregular and rough surface. Water chestnut starch nanocomposites films with varying concentrations of starch nanoparticles (SNPs) were synthesized by a solution casting method. The thickness, moisture content, water vapour transmission rate, water solubility, burst strength of native starch and nano starch composite films were evaluated. The results showed that native starch film had thickness (0.041 ± 0.07 mm) moisture content (4.17 ± 0.32%), water vapour transmission rate (4.678 × 10-3 ± 0.42 g-2 s-1), water solubility (35.71 ± 0.17%) and burst strength (976.4 ± 12.47 g), respectively. The incorporation of SNPs results in an increase in thickness and burst strength while moisture content, water vapour transmission rate and solubility of films were decreased with the increase in the concentration of SNPs which is essential features of a good package.

Comparison of dermal vs internal light administration in human lungs using the TDLAS-GASMAS technique-Phantom studies

Oxygen and water vapor content, in the lungs of a 3D-printed phantom model based on CT-images of a preterm infant, is evaluated using Tunable Diode Laser Absorption Spectroscopy (TDLAS) in Gas in Scattering Media Absorption Spectroscopy (GASMAS), that is, the TDLAS-GASMAS technique. Oxygen gas is detected through an absorption line near 764 nm and water vapor through an absorption line near 820 nm. A model with a lung containing interior structure is compared to a model with a hollow lung. Compared to the model with the hollow lung, both the mean absorption path length and the transmitted intensity are found to be lower for the model with the structured lung. A new approach, where laser light is delivered internally into the model through an optical fiber, is compared to dermal light administration, that is, illumination onto the skin, for the model with structure inside the lung. The internal light administration generally resulted in larger gas absorption, and higher signal-to-noise ratios, compared to the dermal light administration. The results from the phantom measurements show great promise for the internal illumination approach and a natural next step would be to investigate it further in clinical studies.

Regeneration of Fe II /Fe III complex from NO chelating absorption by microbial fuel cell

Ferrous chelates (Fe^IIEDTA) can effectively absorb NO, but the regeneration of them usually consumes large amounts of organic matter or energy. In this study, a new approach to regenerate NO absorbed ferrous chelates with simultaneous electricity generation was investigated by a microbial fuel cell (MFC). The performance and mechanisms of Fe^IIEDTA regeneration were evaluated in the cathode of MFC reactor with and without the presence of microorganisms (referring to biocathode and abiotic cathode), respectively. It was found that Fe^IIEDTA-NO and Fe^IIIEDTA could be used as the cathode electron acceptors in MFC. Low pH (pH = 5) was beneficial to electricity generation and Fe^IIIEDTA/Fe^IIEDTA-NO reduction by the abiotic cathode. The biocathode performed better in electricity generation and Fe^IIEDTA regeneration, and achieved a Fe^IIIEDTA reducing rate of 0.34 h^-1 and a Fe^IIEDTA-NO reducing rate of 0.97 L mmol^-1 h^-1, which are much higher that than those for the abiotic cathode (0.23 h^-1 for Fe^IIIEDTA, 0.44 L mmol^-1 h^-1 for Fe^IIEDTA-NO). This was likely because the activation polarization loss and over cathode potential were reduced as a result of the catalytic activity of NO and iron reducing bacteria.

Sex, but not skin tone affects penetration of red-light (660 nm) through sites susceptible to sports injury in lean live and cadaveric tissues

Red-light treatment is emerging as a novel therapy for promoting tissue recovery but data on red-light penetration through human tissues are lacking. We aimed to: (1) determine the effect of light irradiance, tissue thickness, skin tone, sex and bone/muscle content on 660 nm light penetration through common sites of sports injuries, and (2) establish if cadaver tissues serve as a useful model for predicting red-light penetration in live tissues. Live and cadaver human tissues were exposed to 660 nm light at locations across the skull, spinal cord and upper and lower limbs. Red-light was produced by a light emitting diode array of various irradiances (15-500 mW/cm² ) and measured by a light-probe positioned on the tissue surface opposite to the light emitting diodes. 100 mW/cm² successfully penetrated tissue <50 mm thick; a disproportionate irradiance increase was required to achieve deeper penetration. Penetration was unaffected by skin tone, increased with irradiance and relative bone/muscle composition, and decreased with greater tissue thickness and in males. Live and cadaveric tissue penetration did not differ statistically for tissues <50 mm but cadavers required more red-light to penetrate >50 mm. These results assist clinicians and researchers in determining red-light treatment intensities for penetrating human tissues.