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In contrast to oxygenic photosynthesis, true anoxygenic photosynthesis is not associated with O2 evolution originated from water photolysis but still converts light energy to that of the phosphoanhydride bonds of ATP. In a narrow sense, anoxygenic photosynthesis is mainly known as to be related to the purple and green sulfur bacteria, but in a broad sense, it also occurs in the vascular plants. The portion of photosynthetic water photolysis that is compensated by the processes of O2 uptake (respiration, photorespiration, Mehler cycle, etc.) may be referred to as ‘quasi’ anoxygenic photosynthesis. Photoacoustic method allows for the separate detection of photolytic O2 at frequencies of measuring light about 20–40 Hz, whereas at 250–400 Hz, it detects the photochemical energy storage. We have developed a fast-Fourier transform photoacoustic method enabling measurements of both these signals simultaneously in one sample. This method allows to calculate oxygenic coefficients, which reflect the part of photochemically stored light energy that is used for the water photolysis. We show that the true anoxygenic photosynthesis in Ailanthus altissima Mill. leaves reached very high levels under low light, under moderate light at the beginning of the 1-h period, and at the end of the 40-min period under saturating light.

С помощью метода электроискрового спекания (ЭИС) на основе наноразмерного порошка оксида молибдена создана мелкозернистая (порядка 0,5–1 мкм), плотная (4,57 г/см3), прочная (предел прочности на сжатие 0,1 ГПа, модуль упругости Юнга 60 ГПа) керамика с микротвердостью 2,1 ГПа.

Heavy metals present a threat to human health, even at minimal concentrations within the body. One source of exposure is due to the consumption of low-level contaminated foodstuff and water. Lead and cadmium have been shown to be absorbed by and accumulate within organs like the kidneys and liver, and they have also been associated to many diseases including cardiovascular disease and kidney dysfunction as well as developmental disorders and neurodegenerative diseases. Since this contamination of lead and cadmium is found worldwide, limiting the exposure is complicated and novel strategies are required to prevent the absorption and accumulation of these metals by forcing their elimination. In this study, a DOTAGA-functionalized chitosan polymer is evaluated for this preventative strategy. It shows promising results when orally administered in mice to force the elimination and negate the toxic effects of lead and cadmium found within foodstuff.

While modern agriculture brings more food to people, it causes environmental pollution as well. Agricultural pollution has attracted extensive public attention. A lot of reviews on agricultural research were conducted from different research aspects, but there is a lack of work on analyzing the research trend from large volumes of publications in the field of agricultural pollution. In the present work, a scientometric analysis of agricultural pollution was conducted to fill the gap by using the software of VoSviewer and HistCite™. The datasets are collected from the core database of Web of Science from 1991 to 2019, totally 1338 records on the topic of agricultural pollutions. In most years (1996, 1999, 2002, 2006, 2009, 2011, and 2013), the total local citation score (TLCS) and total global citation score (TGCS) have coincident peaks. Zhang, Ju, and Zhu have the highest TLCS and TGCS. In terms of institutes, Chinese Acad Sci and China Agr Univ are the leading institutes in this field. The Univ Calif Davis, INRA, and USDA ARS have very high global impacts. From the research hot topics, the representative words include "soil," "agriculture," "contamination," "environment," "lead," and "balance." Representative words like "heavy-metals," "groundwater," "land-use," and "water" are emerging in the latter time period. Five leading research co-cited reference clusters are identified, including environment management, underground water, monitoring and alarming for the agriculture-environment standards, intrinsic mechanism to the circulatory system, and ecology system and land use. The recent trend is revealed from the bibliographical-coupling network, focusing on classical and old-fashion research, like pollution chemicals including N management, pesticides, and heavy metal. This work provides a holistic picture on the research in the field of agriculture pollution.

Experiments on the influence of distributed injection of helium on the development of the supersonic boundary layer unstable disturbances have been performed. It is revealed, that injection of helium in a certain range of blowing mass flow rate, leads to a certain decrease of spatial amplification rates of natural disturbances.

Unique plant habitats are described for the petrophytic communities of the Donets ridge. A scientific basis for the conservation of zonal steppe vegetation and its petrophytic variants is proposed using a number of the characteristic petrophytic communities of Donets ridge as examples. Several criteria of conservation importance are proposed to evaluate the reasons for including the natural territories in the list of protected objects. Recommendations for improving the protection of the steppe petrophyte vegetation of the Donetsk ridge are given. Proposals for creating an ecological network within the studied area have been formulated.

Carbon-based nanomaterials are promising for a wide range of biomedical applications, i.e. drug delivery, therapy, and imaging including photoacoustic tomography, where they can serve as contrast agents, biocompatibility and biodistribution of which should be assessed before clinical setting. In this paper, localization of carbon flurooxide nanoparticles, carbon nanodots from β-alanine, carbon nanodots from urea and citric acid and glucose-ethylenediamine nanoparticles (NPs) in organs of Wistar rats were studied by photoacoustic measurements after 24 h of their intravenous injection. 16 ns light pulse from a Q-switched Nd:YAG laser with 1064 nm wavelength was used as an excitation source. The laser-induced photoacoustic signals were recorded with a ring piezoelectric detector. Light absorption by carbon NPs resulted in noticeable enhancement of the photoacoustic amplitude in the tissues where the NPs were accumulated. The NPs were preferably accumulated in liver, kidneys and spleen, and to a lesser extent in heart and gastrocnemius muscles. Together with remarkable fluorescent properties of the studied carbon nanomaterials, their photoacoustic responses allow their application for bi-modal fluorescence-photoacoustic bio-imaging.

Non-destructive methods for the assessment of photosynthetic parameters of plants are widely applied to evaluate rapidly the photosynthetic performance, plant health, and shifts in plant productivity induced by environmental and cultivation conditions. Most of these methods are based on measurements of chlorophyll fluorescence kinetics, particularly on pulse modulation (PAM) fluorometry. In this paper, fluorescence methods are critically discussed in regard to some their possibilities and limitations inherent to vascular plants and microalgae. Attention is paid to the potential errors related to the underestimation of thylakoidal cyclic electron transport and anoxygenic photosynthesis. PAM-methods are also observed considering the color-addressed measurements. Photoacoustic methods are discussed as an alternative and supplement to fluorometry. Novel Fourier modifications of PAM-fluorometry and photoacoustics are noted as tools allowing simultaneous application of a dual or multi frequency measuring light for one sample.

International audience; A simple sensitive method for nonspecific recognition of armagnac, cognac, whiskey, and ethanol/water mixture was developed by using photoluminescence (PL) of carbon nanoparticles (NPs). The carbon NPs were synthesized from the mixture of urea and anhydrous citric acid, followed by few annealing processes to achieve the full effect by solvothermal carbonization. PL features of carbon NPs depend on the alcohol environments in which the NPs are dispersed. PL/PL excitation maps of the alcoholic beverages were mathematically treated, and a final principal component analysis diagram allows visualization of different clusters corresponding to each beverage. The optimal measurement conditions (concentration of NPs in colloidal solution and excitation wavelength) were defined to ensure a reliable recognition level.

Maximal and partial quantum yields of photosystem II (Fv/Fm and Fv–/Fp) in Phaseolus vulgaris leaves were determined in response to the turning on saturating and low (undersaturating) actinic light, accordingly. Measuring lights (ML) of blue, green, and red colors were applied simultaneously using a novel method of the polychromatic fast Fourier transforming pulse amplitude modulation (FFT PAM) chlorophyll fluorometry. Colors of ML were cross-combined with the colors of low and saturating actinic light. Fv/Fm values measured with the green ML were found to be close to that of red light, whereas application of blue ML leads to lower Fv/Fm. In addition, 5-nm resolved excitation spectra were measured to evaluate the dependence between red/far red fluorescence ratios (peak height based – F685/F730, and deconvolved peak square based – F685sq/F730sq) and wavelength of the excitation light. It demonstrates that chlorophyll fluorescence ratio red/far red may be dependent on the spectral absorbance of chlorophyll. The data obtained confirm the results of the previous studies which explain high photosynthetic activity of the green light in terms of redistribution of absorbed quanta throughout thickness of the leaf, thus suggesting possible advisability of green light application in greenhouse lighting, especially for the plants having thick leaves.

A new generation of sensors can be engineered based on the sensing of several markers to satisfy the conditions of the multimodal detection principle. From this point of view, photoacoustic-based sensing approaches are essential. The photoacoustic effect relies on the generation of light-induced deformation (pressure) perturbations in media, which is essential for sensing applications since the photoacoustic response is formed due to a contrast in the optical, thermal, and acoustical properties. It is also particularly important to mention that photoacoustic light-based approaches are flexible enough for the measurement of thermal/elastic parameters. Moreover, the photoacoustic approach can be used for imaging and visualization in material research and biomedical applications. The advantages of photoacoustic devices are their compact sizes and the possibility of on-site measurements, enabling the online monitoring of material parameters. The latter has significance for the development of various sensing applications, including biomedical ones, such as monitoring of the biodistribution of biomolecules. To extend sensing abilities and to find reliable measurement conditions, one needs to clearly understand all the phenomena taking place during energy transformation during photoacoustic signal formation. Therefore, the current paper is devoted to an overview of the main measurement principles used in the photoacoustic setup configurations, with a special focus on the key physical parameters.

International audience; In the paper, combined bi-modal microscopic visualization of biological objects based on reflection-mode optical and photoacoustic measurements was presented. Gas-microphone configuration was chosen for the registration of photothermal response. Precise positioning of the scanning laser beam with modulated intensity was performed employing acousto-optic deflectors. Photoacoustic images are shown to give complementary details to the optical images obtained in the reflected light. Specifically, the photoacoustic imaging mode allows much better visualization of the features with enhanced heat localization due to the reduced heat outflow. For example, the application of the photoacoustic imaging mode was especially successful to visualize Drosophila fly's micro-hairs. Furthermore, the photoacoustic image quality was shown to be adjusted through modulation frequency.

We present results on the photothermal (PT) and heat conductive properties of nanogranular silicon (Si) films synthesized by evaporation of colloidal droplets (drop-casting) of 100 ± 50 nm-sized crystalline Si nanoparticles (NP) deposited on glass substrates. Simulations of the absorbed light intensity and photo-induced temperature distribution across the Si NP films were carried out by using the Finite difference time domain (FDTD) and finite element mesh (FEM) modeling and the obtained data were compared with the local temperatures measured by micro-Raman spectroscopy and then was used for determining the heat conductivities k in the films of various thicknesses. The cubic-to-hexagonal phase transition in Si NP films caused by laser-induced heating was found to be heavily influenced by the film thickness and heat-conductive properties of glass substrate, on which the films were deposited. The k values in drop-casted Si nanogranular films were found to be in the range of lowest k of other types of nanostructurely voided Si films due to enhanced phonon scattering across inherently voided topology, weak NP-NP and NP-substrate interface bonding within nanogranular Si films.

The paper presents the results of the model experiment on spring barley (Hordeum vulgare L.) grown in polluted soil. The influence of separate and combined application of wood biochar and heavy metal-tolerant bacteria on morpho-physiological, anatomical and ultrastructural parameters of H. vulgare L. has been studied. The joint application of biochar and bacteria increased the shoot length by 2.1-fold, root length by 1.7-fold, leaf length by 2.3-fold and dry weight by threefold compared to polluted variant, bringing the plant parameters to the control level. The maximal quantum yield of photosystem II decreased by 8.3% in H. vulgare L. grown in contaminated soil, whereas this decrease was less in biochar (7%), bacteria (6%) and in combined application of bacteria and biochar (5%). As for the transpiration rate, the H. vulgare L. grown in polluted soil has shown a decrease in transpiration rate by 26%. At the same time, the simultaneous application of biochar and bacteria has led to a significant improvement in the transpiration rate (14%). The H. vulgare L. also showed anatomical (integrity of epidermal, vascular bundles, parenchymal and chlorenchymal cells) and ultrastructural (chloroplasts, thylakoid system, plastoglobules, starch grains, mitochondria, peroxisomes, ribosomes, endoplasmic reticulum, vacuoles) changes, revealed by light-optical and transmission electron microscopy of leaf sections. The effects were most prominent in H. vulgare L., grown in polluted soil but gradually improved with application of biochar, bacteria and their combination. The use of biochar in combination with metal-tolerant bacteria is an efficient tool for remediation of soils, contaminated with heavy metals. The positive changes caused by the treatment can be consistently traced at all levels of plant organization.

Zinc based nanoparticles (NPs) have a great importance among the metal-based NPs and widely produced after SiO2 and TiO2. The rapid growth of ZnO NPs production and its abundant uses in many industries, and increasing release into an environment from both intentional and unintentional sources, create risks to human health. The recent finding of ZnO NPs application indicates positive and negative effects on plant growth. However, studies exploring the effect of ZnO NPs on the internal organelles of plants and their correlation with the function of photosynthesis are a few. The spring barley (Hordeum sativum L.) is one of the most important staples food crop and is identified as an efficient potentially toxic elements accumulator with phytoremediation potential. Thereby, the present work aimed to investigate the toxic effects of ZnO NPs on physiological and anatomical indices of H. sativum growth grown in a hydroponic condition as it allows to simplify model, where the parameters of plant growth can be easily controlled. Thus, the commercial-grade ZnO NPs (particle size 30-50 nm) was used with the scheme; control (0 ppm), low (300 ppm ZnO NPs), and high (2000 ppm ZnO NPs) the dose of NPs. The low and high levels of ZnO NPs were selected with consideration for the existing levels of Zn in the polluted soils. The results showed ZnO NPs affected the photosynthetic efficiency of H. sativum plants by affecting chlorophyll fluorescence emission, deformation in stomatal and trichomes morphology, damaged cellular organizations, i.e., irregularities in chloroplasts, disruption in grana and thylakoid organizations. Cytomorphometric quantification revealed that ZnO NPs decreased chloroplasts size 4 times in 2000 ppm and 1.5 times in 300 ppm ZnO NPs treated plants. The lower number of chloroplasts per cell were observed in ZnO NPs treated H. sativum leaf cells. The destructive methods of Zn elemental analysis showed 10.2 folds and 3.8 folds higher accumulation in 2000 ppm and 300 ppm ZnO NPs treated leaves than the control, respectively. Additionally, the presence of Zn content in H. sativum leaf tissue was also confirmed by the X-ray fluorescence spectroscopy elemental analysis. The high contents of Zn were visible in several spots in ZnO NPs treated leaf tissues. The accumulation of Zn content dissolute from ZnO NPs damaged the structural organization of the photosynthetic apparatus and reduced the photosynthetic activities. The modifications in anatomical indices were significantly correlated with physiological observations. The work presented here will help to increase the scientific understanding of the toxicity of ZnO NPs in plants and will widen the scope to tailor the nanomaterials to improve the effectiveness, smart and targeted delivery to avoid damages of most significant tissues of plants. This study was funded by the RFBR, project nos. 19-34-60041 and 18-29-25071, and the Ministry of Science and Higher Education of Russia, project no. 0852-2020-0029.

Gadolinium-based radiosensitizing AGuIX nanoparticles (AGuIX) currently tested two phase 2 clinical trials in association with radiotherapy for the treatment of brain metastases. Here, excitatory/inhibitory neurotransmission was assessed in rat cortex nerve terminals in the presence of AGuIX and their constituents (DOTAGA and DOTAGA/Gd3+) at concentrations used for medical treatment, and those 5–24 times higher. The ambient level, transporter-mediated, tonic and exocytotic release of L-[14C]glutamate and [3H]GABA, the membrane potential of nerve terminals were not changed in the presence of AGuIX at concentrations used for medical treatment ([Gd3+] = 0.25 mM, corresponding to 0.25 g.L−1), and DOTAGA (0.25 mM) and DOTAGA/Gd3+ (0.25 mM/0.01 mM). Difference between AGuIX and the precursors was uncovered, when their concentrations were increased. AGuIX (1.25–6 mM) did not change any transport characteristics of L-[14C]glutamate and [3H]GABA, whereas, DOTAGA (1.25–6 mM) affected the membrane potential, ambient level, and exocytotic release of L-[14C]glutamate and [3H]GABA. Gd3+ did not mask, but even enhanced above effects of DOTAGA. Therefore, AGuIX did not influence glutamate- and GABA-ergic neurotransmission at the presynaptic site. In contrast, DOTAGA and mixture DOTAGA/Gd3+ significantly affected synaptic neurotransmission at high concentrations. AGuIX own structure that overcomes neurotoxic features of their constituents.

Nitrogen- and oxygen-containing carbon nanoparticles (O, N-CDs) were prepared by a facile one-step solvothermal method using urea and citric acid precursors. This method is cost-effective and easily scalable, and the resulting O, N-CDs can be used without additional functionalization and sample pretreatment. The structure of O, N-CDs was characterized by TEM, AFM, Raman, UV-vis, and FTIR spectroscopies. The obtained O, N-CDs with a mean diameter of 4.4 nm can be easily dispersed in aqueous solutions. The colloidal aqueous solutions of O, N-CDs show significant photothermal responses under red-IR and radiofrequency (RF) irradiations. The as-prepared O, N-CDs have a bright temperature-dependent photoluminescence (PL). PL/PLE spectral maps were shown to be used for temperature evaluation purposes in the range of 30–50 °C. In such a way, the O, N-CDs could be used for biomedicine-related applications such as hyperthermia with simultaneous temperature estimation with PL imaging.

Cytotoxicity of fluorescent carbon fluoroxide (CFO) nanoparticles (NPs) was studied in a label-free manner on several cancer and non-cancer cell lines. A direct cytotoxic effect of the CFO NPs was clearly observed by a suppression of cell proliferation. The real-time measurement of cell activities allowed to quantify the impact of the uptaken NPs on cell proliferation and after washout of the NPs from the cell culture medium. The results show more toxic effects of the CFO NPs on cancer than on non-cancer cell lines. The notion of NPs biocompatibility must be related to a maximum concentration value of the NPs acceptable for a given cell type. Furthermore, the cytotoxicity effects of NPs should be studied not only during their direct exposure to cells but also after their washout from the culture medium., Nanoletters, 11 (12), ISSN:2079-4991

International audience; In the present paper, we report on the investigation of thermal annealing (TA) effect on structural and optical properties of crystalline silicon nanowires produced by metal-assisted chemical etching approach. In particular, the impact of TA on nanowire length, relative volume and size distribution of voids is described in terms of Lifshitz-Slyozov-Wagner theory considering the TA induced Oswald ripening in the SiNW arrays. It was also found that TA leads to a decrease of the SiNWs total reflection in the wide UV-VIS-IR spectral range. The reported effects can be used for tuning of crystalline SiNWs arrays in view of their further applications in photonics related fields.

International audience; The photoacoustic method with piezoelectric detection for the simultaneous evaluation of the thermophysical properties is proposed. The approach is based on the settling of an additional heat sink for redistribution of heat fluxes deposited on the sample surface. Firstly, the approach was tested on the porous silicon with welldefined morphology and well-studied properties. Then, heat capacity and thermal conductivity of silicon nanowires arrays have been investigated by recovering the experimental data through numerical simulations. The decrease of heat capacity and effective thermal conductivity of the samples upon increasing thickness and porosity of the sample is observed. Such behavior could be caused by the increase of the structure heterogeneity. In particular, this can be related to larger disorder (increased density of broken nanowires and larger porosity) that appears during the etching process of the thick layers.

Being part of a higher-order basin system, Seversky Donets River is an important object to study nitrogen nutrient pollution in the water area of Azov and Black Sea Basins. In this work, we researched nitrate, ammonium ion and dissolved oxygen concentrations in Seversky Donets River, a tributary of Don River, in two sampling points of the upper (tailwater of Belgorod reservoir and vicinity of Novaya Tavolzhanka Village) and one sampling point of the lower (vicinity of Russian–Ukrainian border) course. The obtained analytical data show that NH4+/NO3− annual average ratio was sufficiently increased during 15-year period, whereas there were no decrease in the annual average oxygen concentrations and sufficient temperature changes in the same sampling points. The possible role of the nitrification in this trend and reliability of the applied analytical methods are discussed. In addition, we show that S. Donets River may contribute up to 70–80% of total NO3− pollution and 55–65% of total NH4+ pollution in Don River, contributing only about 30% of total Don River discharge.

This study focuses on the mechanical response of silicon on porous silicon bilayer cantilevers ended with a seismic mass. The porous silicon is intended to provide an alternative to decrease the cantilever stiffness for low-frequency MEMS applications. The first eigenfrequency of the cantilever is obtained using static deflection obtained under classical Euler-Bernoulli assumptions and Rayleigh method. In order to estimate the errors due to small-strain approximation and Euler-Bernoulli theory, the analytical results were validated through 3D finite element simulations for different cantilever geometries and porosities. Both bulk silicon and silicon on porous silicon bilayer cantilevers ended with a seismic mass were fabricated and we measured the first eigenfrequency (f0) and quality factor (Q) by using a laser Doppler vibrometer. In agreement with the theoretical predictions we found that, when compared to bulk silicon cantilevers, the first eigenfrequency of a bilayer cantilever containing 6% porous silicon (at 50% porosity) on 94% bulk silicon is lowered by 5%, from (5447 ± 120) Hz to ≈ 5198 Hz. This decrease is also accompanied by a reduction of the quality factor by two.

The experimental investigation of the influence of the distributed blowing of heavy gas (sulfur hexafluoride of SF6) into the wall layer of supersonic flat-plate boundary layer (at free-stream Mach number M = 2) on the laminar-turbulent transition have been performed. For the first time experimentally it is shown that in case of such blowing there is a boundary-layer stabilization, and the laminar-turbulent transition is removed from the model leading edge.

Ця стаття присвячена вивченню різних наноматеріалів на основі вуглецю як фотоакустичних контрастних речовин. Дослідницька робота проводилася на фантомі тканини на основі агарози, що містить включення з карбоновими наноматеріалами та без них. Включення було створено з більш високою густиною порівняно з фантомом з метою імітування пухлини. Для вимірювання рівня фотоакустичного сигналу та його підсилення, спричиненого наявністю нановключень, було використано спеціально розроблений фотоакустичний зонд. Зонд складається з буфера для часового розділення сигналу, що надходить від джерела збудження, п'єзоелектричного перетворювача та підсилювача. Точкові вимірювання сигналу проводилися для отримання двовимірної карти величини фотоакустичного сигналу та фазової затримки реєстрації сигналу. На основі затримки фази реконструювали фотоакустичні 3D зображення шляхом оцінки координати глибини на основі швидкості звуку в тканині. Як джерело збудження було використано світлове випромінювання від Nd:YAG лазера з тривалістю імпульсу 16 нс та довжиною хвилі 1064 нм. По-перше, ми розглядали тканинний фантом із пухлиною, покритою оксидом графена (GO) в якості контрольного. Показано, що використання GO призводить до значного поліпшення контрасту зображення. Далі систематично вивчалися пухлини, покриті нанодіамантами (NDs) та наночастинками фтороксиду вуглецю (CFO). Амплітуда фотоакустичних сигналів, зареєстрованих від таких фантомів пухлини, на порядок менша, ніж сигнал, одержуваний від GO. Всі три типи досліджуваних наноматеріалів на основі вуглецю (GO, NDs, CFO) дають стабільний фотоакустичний сигнал, що дозволяє вважати їх хорошими кандидатами для подальших експериментів in vitro у фотоакустичній візуалізації для біологічних застосувань. Залежності рівня сигналу від концентрації наночастинок вимірювали для окремих типів наночастинок. Враховуючи набагато ефективніше проникнення NDs та CFO наночастинок всередину клітин, а також їх надзвичайно низьку цитотоксичність, ці обидва типи вуглецевих наноматеріалів можуть бути використані для подальших експериментів in vivo. This paper is devoted to the study of various carbon-based nanomaterials as photoacoustic contrast agents. The research work was performed on agarose-based tissue phantom containing inclusions with and without carbon-based nanomaterials. The inclusion was created with the higher density compared to phantom in order to simulate a tumor. A specially designed photoacoustic probe was introduced for measuring a level of photoacoustic signal and its enhancement caused by the nanoinclusions presence. The probe consists of a buffer for time separation of the signal coming from the excitation source, piezoelectric transducer, and amplifier. A point-by-point measurement of the signal was performed to obtain a two-dimensional map from magnitude of photoacoustic signal and phase delay of the signal registration. From phase delay the 3D photoacoustic images were reconstructed by evaluation of the depth coordinate based on the tissue sound velocity. As an excitation source the light radiation from Nd:YAG laser with a 16 ns pulse duration and a 1064 nm wavelength was used. Firstly, we considered tissue phantom with a tumor covered by graphene oxide as a reference one. It has been shown that the use of graphene oxide leads to significant improvement of the image contrast. Further, the tumors labelled with nanodiamonds (NDs) and carbon fluoroxide (CFO) nanoparticles (NPs) were studied systematically. Amplitude of the photoacoustic signals registered from such tumor phantoms are one order of magnitude lower than the signal ensured by graphene oxide. All three types of the studied carbon-based nanomaterials (GO, NDs, CFO) give stable photoacoustic signal, this allows to consider them as good candidates for further in-vitro experiments in photoacoustic imaging for biological applications. The dependences of the signal level as a function of the NPs concentration were measured for types of NPs. Considering much more efficient penetration of NDs and CFO NPs inside the cells as well as their extremely low cytotoxicity, these both types of carbon nanomaterials could be used for further in-vivo experiments.

Mesoparticles with characteristic sizes larger than all known molecules and smaller than usual nanoparticles can easily penetrate inside living cells. Thus, they appear to be especially promising for cancer theranostic application. However, presence of mesoparticles can strongly perturb physico-chemical properties of the biological media in which they are incorporated, it is crucial to know a magnitude of such perturbations. For example, thermal properties of liquid solutions with dispersed mesoparticles are crucial for development of theranostic approaches based on photoacoustic effect. In this paper, thermal transport in nanofluids formed by carbon flurooxide (CFO) mesoparticles is reported. A significant non-linear enhancement of the thermal conductivity of the nanofluids (up to 85%, in comparison with initial basic liquids) depending on volume fraction of the dispersed CFO mesoparticles was found. It was revealed that the thermal conductivity rise can be explained by existence of interfacial layers between the mesoparticles and the hosting liquids.

International audience; Features of heat transport in silicon-based porous structures with different morphology before and after thermal annealing are investigated. Specifically, fractal-like porous silicon and silicon nanowire arrays samples were considered. All the structures were annealed in dry air at various temperatures in diapason from 600 °C up to 1000 °C for 20 minutes. The photoacoustic technique with gas-microphone registration was applied for the thermal diffusivity evaluation of the samples. Particularly, the amplitude frequency dependencies of photoacoustic response from the considered samples in the classical gas-microphone configuration were measured in the range from 10 Hz to 3 kHz. The simulation of the experimental dependencies with the use of appropriate model allowed us to evaluate thermal conductivity. It was found that the short time thermal annealing together with increasing annealing temperature leads to significant reduction of thermal transport in mesoporous silicon. On the opposite, the thermal properties of silicon nanowires remain unaffected.

Silicon-rich nitride nanocomposites with stable multicolour photoluminescence (PL) are developed in this work. Firstly, a single PL band can be adjusted in the visible spectral range. Secondly, simultaneous emission of an additional PL band is achieved due to boron-doping of the nanocomposites. Impact of thermal annealing of the silicon nitride films in different atmospheres at various temperatures on their PL spectra is studied. Processes responsible for multicolour emission in the boron-doped nanocomposites are discussed. The developed nanocomposites can be further applied for nanothermometry or biosensing applications. They can be also used for synthesis of silicon nanoparticles with multicolour PL. Intense violet-based multicolour photoluminescence of silicon nitride nanocomposite with tunable emission position is achieved.

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In this study, we investigated the thermal transport in porous silicon nanostructures and silicon nanowires fabricated by electrochemical and metal-assisted chemical etching processes, respectively. In particular, the thermal conductivity values for the silicon-based nanomaterials were estimated based on photoacoustic measurements obtained from piezoelectric recordings. The amplitude–frequency and phase–frequency dependencies of the photoacoustic responses of the nanostructured silicon samples were obtained, and simulated successfully with a theoretical model. Correlations were established between the thermal conductivities and etching parameters.

The aim of the present work was to investigate the toxic effects of zinc oxide nanoparticles (ZnO NPs, particle size &lt, 50 nm) on the physiological and anatomical indices of spring barley (Hordeum sativum L.). The results show that ZnO NPs inhibited H. sativum growth by affecting the chlorophyll fluorescence emissions and causing deformations of the stomatal and trichome morphology, alterations to the cellular organizations, including irregularities of the chloroplasts, and disruptions to the grana and thylakoid organizations. There was a lower number of chloroplasts per cell observed in the H. sativum leaf cells treated with ZnO NPs as compared to the non-treated plants. Cytomorphometric quantification revealed that ZnO NPs decreased the size of the chloroplast by 1.5 and 4 times in 300 and 2000 mg/L ZnO NP-treated plants, respectively. The elemental analysis showed higher Zn accumulation in the treated leaf tissues (3.8 and 10.18-fold with 300 and 2000 mg/L ZnO NPs, respectively) than the untreated. High contents of Zn were observed in several spots in ZnO NP-treated leaf tissues using X-ray fluorescence. Deviations in the anatomical indices were significantly correlated with physiological observations. The accumulation of Zn content in plant tissues that originated from ZnO NPs was shown to cause damage to the structural organization of the photosynthetic apparatus and reduced the photosynthetic activities.

Oxygen evolution and chlorophyll fluorescence kinetics in cells of the Chlorella vulgaris strain (Europolytest, Russia) were studied under low, moderate and high photosynthetic photon flux densities (PPFD 40, 130 and 350 μmol photons m–2 s–1) of the red and blue actinic light. A novel method of a pulse amplitude modulated (PAM) Fourier chlorophyll fluorometry was applied to obtain photoinduction curves simultaneously for the red and blue measuring light for one sample. It was found that the red light did not induce oxygen evolution at low and moderate PPFD, whereas at high PPFD it caused a declining oxygen release. There was only a trace fluorescence kinetics at the low PPFD, but noticeable fluorescence kinetics under the red light was observed at the low and moderate PPFD. Particularly, the moderate red illumination of Chlorella cells excited a high chlorophyll fluorescence kinetics along with the absence of oxygen evolution that suggests anoxygenic photosynthesis. In contrast, the blue light induced a significant oxygen evolution as well as fluorescence kinetics already at low PPFD which were both further increased with the PPFD increasing. In addition, a high value of the chromatic divergence of quantum yield of photosystem II was revealed between the red and blue measuring light under high PPFD of the red actinic light.

Hydrogen generation rate is one of the most important parameters which must be considered for the development of engineering solutions in the field of hydrogen energy applications. In this paper, the kinetics of hydrogen generation from oxidation of hydrogenated porous silicon nanopowders in water are analyzed in detail. The splitting of the Si-H bonds of the nanopowders and water molecules during the oxidation reaction results in powerful hydrogen generation. The described technology is shown to be perfectly tunable and allows us to manage the kinetics by: (i) varying size distribution and porosity of silicon nanoparticles, (ii) chemical composition of oxidizing solutions, (iii) ambient temperature. In particular, hydrogen release below 0 &deg, C is one of the significant advantages of such a technological way of performing hydrogen generation.

The applications of nanoparticles on aquatic and terrestrial ecosystems are increasing and receiving a great scientific attention due to its toxicity effects. The phytotoxicity of nanoparticles is mainly expressed by suppressed germination percentage, impact on morphometric parameters, for instance, root and shoot length, root hairs, biomass, bio-molecules, and cellular damages such as lipid peroxidation, protein damage, membrane destruction, chlorophyll fluorescent, transpiration rate, and photosynthesis. Recent studies indicate several changes in plant cell organelles such as a disruption in the cell wall, cell membrane, chloroplast structure, thylakoids, abnormal size of plastoglobules and starch granules, destructive changes in peroxisomes, swollen mitochondrial cristae, abnormal nucleus, loose, rough and thin mesophyll cells, epidermal, cortical, and stellar cells. Deposition of electronically dense materials near cell walls is also observed. These changes in plant cells impact the plant growth. This is the first chapter to highlight the toxicity of nanoparticles on the plants at anatomical and ultrastructural level.

International audience; Critical analysis of the data reported by Zhong et al. (J. Am. Chem. Soc.2013, 135 (22), 8350–8356) is carried out. In particular, one of the main results of Zhong et al. concerning the formation of photoluminescent silicon nanoparticles (Si NPs) in an aqueous solution of (3-aminopropyl)trimethoxysilane (APTMS) and trisodium citrate dihydrate (Na3Cit) under microwave heating is impugned. These results are reconsidered here because of what appear to be significant inaccuracies and misinterpretations that have been spread through a wide number of other subsequent publications.

We have investigated the thermal transport in anisotropic nanostructured materials. Particularly, porous silicon and silicon nanowires arrays have been considered in this work. For thermal conductivity evaluation Raman technique has been applied. The thermal transport anisotropy is more pronounce in silicon nanowires array than in porous silicon. Yet, the in-plane and cross-plane thermal conductivities of porous silicon differ approximately in twice. Both values are in a good agreement with the literature.

Laser ultrasound enhancement with carbon-based nanomaterials incorporated into phantom tissues is reported. More specifically, impact of nanodiamonds and graphene oxide on the efficiency of photoinduced pressure excitation was investigated. Agarose-based phantom tissues with and without the nanoparticles were compared. The second harmonic of pulsed Nd:Yag laser (532 nm) was chosen for ultrasound generation. Specific acoustic probe was fabricated for laser-induced ultrasound registration. Dependence of the ultrasound amplitude on concentration of the nanoparticles incorporated into the phantom tissues was analyzed in details. The most significant enhancement of the amplitude ensured by graphene oxide was stated. Considering biocompatibility of the both types of carbon-based nanomaterials, they can be potentially used in future as contrast agents for bio-imaging and theranostic applications.

Features of thermal transport in multilayered porous silicon nanostructures are considered. Such nanostructures were fabricated by electrochemical etching of monocrystalline Si substrates by applying periodically changed current density. Hereby, the multilayered structures with specific phononic properties were formed. Photoacoustic (PA) technique in gas-microphone configuration was applied for thermal conductivity evaluation. Experimental amplitude-frequency dependencies were adjusted by temperature distribution simulation with thermal conductivity of the multilayered porous structure as a fitting parameter. The experimentally determined values of thermal conductivity were found to be significantly lower than theoretically calculated ones. Such difference was associated with the presence of thermal resistance at the interfaces between porous layers with different porosities arising because of elastic parameters mismatch (acoustical mismatch). Accordingly, the magnitude of this interfacial thermal resistance was experimentally evaluated for the first time. Furthermore, crucial impact of the resistance on thermal transport perturbation in a multilayered porous silicon structure was revealed.

Autophagy in flower petal epidermal cells is a little studied process. However, it is of interest regarding the physiology of chlorophylless plant tissues. We show that the utilization of organelles in the Petunia hybrida L. flower petal epidermis occurs via the autophagic-like organelle targeting into vacuole during the particular process of vacuole fragmentation and growth of secondary vacuoles (ATVF). It differs from macroautophagy (formation of autophagosome) and microautophagy. Peroxisomes were shown to be subjected to both macroautophagy (as single microbodies and their assemblies) and to ATVF when they are in complexes with mitochondria and chromoplasts. In addition, we have demonstrated that ATVF in flower petals is accompanied with the sequestration of the cytoplasmic sectors located between the neighboring cell wall ingrowths, the ultrastructure of which has been reported in the present work for the first time. It has been shown there are more numerous mitochondria, a more pronounced ATVF, and a thicker cytoplasmic layer in the blue tissues, possibly reflecting more intensive metabolic processes in them compared to white tissues. We assume that these differences may be of interest for the further studies and may be discussed including in terms of anthocyanin-dependent photochemical effects.

Chemical nature of products, formed during electrochemical dissolution of polycrystalline 3C-SiC substrate in HF:ethanol mixture, was studied by means of FTIR spectroscopy, temperature-programmed desorption mass spectrometry (TPD-MS), 1H, 13C, and 19F NMR (solution as well as MAS), XPS, AFM, and other characterization methods. Simultaneous formation of two major products, porous SiC and carbon fluorooxide (CFO) nanoparticles (NPs) with sizes of 1–10 nm, is described. CFO NPs easily dissolve in polar organic solvents (ethanol, CH2Cl2, etc.); their solutions demonstrate intense yellowish-green photoluminescence under UV excitation. A model of the CFO chemical structure based on relatively small graphene domains interconnected with partially fluorinated hydrocarbon groups and terminated by carboxylic acid (−CO2H), ethyl ester (−CO2C2H5), perfluorinated functional groups, and polycarboxylated alkyl chains is proposed. Presence of carboxylates allows easy functionalization of the CFO NPs via amide chemistry. In particular, grafting of octadecyl groups makes CFO NPs soluble in hydrocarbons., The authors are grateful to IRSES European Project “Porous Silicon Carbide as a support for Co metal nanoparticles in Fischer−Tropsch synthesis” (proposal number: 319013) and Visby Swedish institute project 00814/2011 “Surface-Assisted Laser Desorption Ionization of biomolecules on modified porous Silicon/Silicon Carbide for their better analysis” for partial financial support.

Raman scattering and second-harmonic generation processes in porous layers obtained by the electrochemical etching of polycrystalline silicon carbide, which contain nanocrystals with dimensions from several to hundreds of nanometers, have been studied. It has been found that the efficiencies of Raman scattering and second-harmonic generation in layers of porous silicon carbide increase by several times and more than two orders of magnitude, respectively, compared to the values in the initial sample. The efficiency of transformation to the second harmonic reaches 0.1% at pumping by femtosecond pulses with a wavelength of 1240 nm. The lifetime of a photon in layers of porous silicon carbide has been estimated as more than 2 ps from the measurement of the cross-correlation functions; this value indicates the deceleration of light in this optically inhomogeneous medium owing to multiple scattering. This effect in layers of porous silicon carbide explains the observed increase in the efficiencies of Raman scattering and second-harmonic generation.

Middle Don basin is recognized as a biodiversity hotspot, characterized by high diversity of vascular terrestrial plants. However, the significance of its freshwater biodiversity is not well understood now. In the given paper we present the results of the investigation of higher aquatic flora of basin streams and reservoirs within the Middle Don, Rostov region. 90 species of 53 genera and 32 families belonging to the four departments of higher plants were identified. The biodiversity of the Middle Don aquatic flora is discussed using the previously obtained herbal and biogeographic data and considering ecological, geographical and human factors. A systematic, ecological and geographical analysis of the regional aquatic flora has been conducted.

Characterization of cell death currently requires the use of indirect markers, which has largely limited the ability to monitor cell death processes inside the cell. Here, we introduce a new method for the characterization of cell death mechanisms using cadmium telluride quantum dots (CdTe-QDs). Using visible CdTe-QDs with mesenchymal cells (e.g. synoviocytes), live-stream imaging allowed for visualization of cadmium-induced cell death, combining characteristics of apoptosis and autophagy. Initially, similar anti-proliferative effect was observed between 10 µg/ml Cd2+ and CdTe-QDs at 24 h (cell index/cell density ratio decreased from 0.6 to −16.6, p 2+ and CdTe-QD. However, QD imaging allowed for visualization of cadmium elements inside cell structures and their kinetic changes leading to cell death. Cell death characteristics were similar in inflammatory and non-inflammatory environment but were induced up to 4 h earlier in the former. Therefore, live-stream imaging of a visible cytotoxic agent has useful applications not currently possible with indirect methods, including chronological monitoring of cell death.

Self-regulated hydrogen production at room temperature and atmosphere pressure is described in details.Basic idea of our approach is based on a precise auto-tuning of the oxidizing aqueous solution arrival ontohydrogenated silicon or aluminum nano-powders. The used self-regulation principle is completely passivee.g. neither electrical power sources, no regulating electronics are required. The system functioning wassimulated numerically and checked experimentally. The numerical simulation allowed definition of themain optimal parameters of the working system (pressure, capillary tube diameter, tank volumes) and anexperimental prototype based on the simulated results was built and used for hydrogen supplying to aportable PaxiTech® fuel cell.

International audience; Chemical transformations on the surface of commercially available 3C-SiC nanoparticles were studied by means of FTIR, XPS, and temperature-programmed desorption mass spectrometry methods. Thermal oxidation of SiC NPs resulted in the formation of a hydroxylated SiO2 surface layer with C3Si–H and CHx groups over the SiO2/SiC interface. Controllable oxidation followed by oxide dissolution in HF or KOH solution allowed the SiC NPs size tuning from 17 to 9 nm. Oxide-free SiC surfaces, terminated by hydroxyls and C3Si–H groups, can be efficiently functionalized by alkenes under thermal or photochemical initiation. Treatment of SiC NPs by HF/HNO3 mixture produces a carbon-enriched surface layer with carboxylic acid groups susceptible to amide chemistry functionalization. The hydroxylated, carboxylated, and aminated SiC NPs form stable aqueous sols.