Melatonin seed priming improves early establishment and water stress tolerance of peanut.

Water stress is a major cause of yield loss in peanut cultivation. Melatonin seed priming has been used to enhance stress tolerance in several crops, but not in peanut. We investigated the impact of seed priming with melatonin on the growth, development, and drought tolerance of two peanut cultivars, TUFRunner™ '511', a drought tolerant cultivar, and New Mexico Valencia A, a drought sensitive cultivar. Peanut seed priming tests using variable rates of melatonin (0-200 µM), indicated that 50 µM of melatonin resulted in more uniform seed germination and improved seedling growth in both cultivars under non stress conditions. Seed priming with melatonin also promoted vegetative growth, as evidenced by higher whole-plant transpiration, net CO2 assimilation, and root water uptake under both well-watered and water stress conditions in both cultivars. Higher antioxidant activity and protective osmolyte accumulation, lower reactive oxygen species accumulation and membrane damage were observed in primed compared with non-primed plants. Seed priming with melatonin induced a growth promoting effect that was more evident under well-watered conditions for TUFRunnner™ '511', whereas for New Mexico Valencia A, major differences in physiological responses were observed under water stress conditions. New Mexico Valencia A primed plants exhibited a more sensitized stress response, with faster down-regulation of photosynthesis and transpiration compared with non-primed plants. The results demonstrate that melatonin seed priming has significant potential to improve early establishment and promote growth of peanut under optimal conditions, while also improve stress tolerance during water stress.

Effect of melatonin foliar sprays on morphophysiological attributes, fruit yield and quality of Momordica charantia L. under salinity stress.

Soil salinity is one of the increasing problems in agricultural fields in many parts of the world, adversely affecting the performance and health of the plants. As a pleiotropic signal and antioxidant molecule in both animals and plants, melatonin has been reported to possess significant roles in combating with stress factors, in general and salt stress, in particular. In this study, the interactive effects of melatonin (0, 75, and 150 µM) and salt stress (0, 50 and 100 mM NaCl) were investigated by assaying the some agronomic, physlogical and biochemical attributes and essential oil compounds of bitter melon (Momordica charantia). The results showed that exogenous melatonin could promote net photosynthetic rate (Pn) and PSII efficiency (Fv/Fm), increase K+ content and activity of antioxidant enzymes and decrease reactive oxygen species, malondialdehyde and Na+ content in stress-submitted seedlings, in comparison to the non-stressed seedlings (p < 0.05). Melatonin increased content of essential oils. Concerning the major compounds of fruits of bitter melon, charantin, momordicin and cucurbitacin were increased with the melatonin treatments, whereas they were critically decreased with the salt stress. In addition, melatonin increased the antioxidant capacity in fruits under non-saline and salinity conditions. Amid the concentrations of melatonin, plants treated with 150 µM of melatonin under either non-saline or saline conditions showed better performance and productivity. Therefore, application of 150 µM melatonin resulted in a significant improvement of salinity tolerance and essential oil compounds in bitter melon plant, suggesting this as an efficient 'green' strategy for sustainable crop production under salt stress conditions.

Staphylococcus epidermidis induced toxic shock syndrome (TSS) secondary to influenza infection.

BACKGROUND: To date, few cases of TSS caused by coagulase negative (CoN) staphylococci have been reported in the literature. Recent data show that CoN staphylococci are capable of secreting a number of enterotoxins and cytotoxins, normally produced by S. aureus. Herewith, we describe a case of TSS caused by Staphylococcus epidermidis with a favorable outcome. CASE PRESENTATION: We report a case of a 46-year-old man who developed TSS from S. epidermidis. The patient was admitted for a 7-day history of general malaise and headache following a recent influenza infection and a 3-day history of vomiting, diarrhea, diffuse erythroderma, and fever. The main laboratory findings on admission were leukopenia (WBC 800/mm3), thrombocytopenia (Plt count 78.000/mm3), elevated urea, creatine levels and increased inflammatory markers (CRP 368 mg/ml). The patient had clinical and radiological evidence of pneumonia with chest computed tomography (CT) showing diffuse bilateral airspace opacifications with air bronchogram. On the second day, a methicillin resistant S. epidermidis (MRSE) strain was detected in both sets of blood cultures, but the organism was unavailable for toxin testing. All other cultures and diagnostic PCR tests were negative. His clinical signs and symptoms fulfilled at that stage four out of five clinical criteria of TSS with a fever of 39 °C, diffuse erythroderma, multisystem involvement and hypotension. On the same day the patient was admitted to the ICU due to acute respiratory failure. The initial treatment was meropenem, vancomycin, levofloxacin, clindamycin, IVIG and steroids. Finger desquamation appeared on the 9th day of hospitalization, fulfilling all five clinical criteria for TSS. CONCLUSIONS: To our knowledge, this is the first adult case with TSS induced by CoNS (MRSE) secondary to an influenza type B infection, who had favorable progression and outcome. Further research is warranted to determine how TSS is induced by the CoNS infections.

In vivo brain temperature mapping using polymer optical fiber Bragg grating sensors.

Variation of the brain temperature is strongly affected by blood flow, oxygen supply, and neural cell metabolism. Localized monitoring of the brain temperature is one of the most effective ways to correlate brain functions and diseases such as stroke, epilepsy, and mood disorders. While polymer optical fibers (POFs) are considered ideal candidates for temperature sensing in the brain, they have never been used so far in vivo. Here, we developed for the first, to the best of our knowledge, time an implantable probe based on a microstructured polymer optical fiber Bragg grating (FBG) sensor for intracranial brain temperature mapping. The temperature at different depths of the brain (starting from the cerebral cortex) and the correlation between the brain and body core temperature of a rat were recorded with a sensitivity of 33 pm/°C and accuracy <0.2°C. Our in vivo experimental results suggest that the proposed device can achieve real-time and high-resolution local temperature measurement in the brain, as well as being integrated with existing neural interfaces.

Femtosecond laser inscribed fiber Bragg gratings based on precise spatial apodization.

Plane-by-plane femtosecond laser fabricated apodized fiber Bragg gratings (FBG) are demonstrated for the first time, to the best of our knowledge. The method reported in this work provides a fully customizable and controlled inscription that can realize any desired apodized profile. By using this flexibility, we experimentally demonstrate four different apodization profiles (Gaussian, Hamming, New, Nuttall). These profiles were chosen to evaluate their performance with regard to the sidelobe suppression ratio (SLSR). Usually, a higher reflectivity of a grating fabricated with a femtosecond laser will result in a greater difficulty to achieve a controlled apodization profile due to the nature of the material modification. Therefore, the goal of this work is to fabricate high-reflectivity FBGs without sacrificing the SLSR and provide a direct comparison with apodized low-reflectivity FBGs. In our weak apodized FBGs, we also consider the background noise introduced during the femtosecond (fs)-laser inscription process which is fundamental when multiplexing FBGs within a narrow wavelength window.

Gamma-radiation enhancement of sensing properties of FBGs in a few-mode polymer CYTOP fiber.

We investigate the effect of γ-radiation on temperature (T) and relative humidity (RH) sensitivities of polymer perfluorinated fiber Bragg gratings (FBGs). To this aim, different γ-radiation doses (80, 120, 160, and 520 kGy) were applied to a set of FBGs. We show that irradiated FBGs demonstrate an RH sensitivity rise with the received dose: from 13.3 pm/%RH for a pristine FBG up to 56.8 pm/%RH for a 520-kGy dose at 30℃. In contrast, T sensitivity decreases with radiation dose with a subsequent change of sign from positive to negative. Therefore, by experimental interpolation, T sensitivity can be eliminated at around a 160-kGy dose. This opens the possibility of designing an RH sensor with enhanced sensitivity, which at the same time is insensitive to T.

Mitigation of salinity impact in spearmint plants through the application of engineered chitosan-melatonin nanoparticles.

High soil salinity represents a critical environmental constraint to crop production. In order to ameliorate the effects of salinity, a plethora of molecules have been applied and promising outcomes have been noted. The beneficial effects of chitosan (CTS) and melatonin (Mel) application, separately, have been previously recorded with respect to plant growth and productivity, leading to the hypothesis that their conjugation in the form of chitosan-melatonin nanoparticles (CTS-HPMC-Mel NPs) could lead to further enhanced performance of plants under control and stress conditions. In this regard, novel CTS-HPMC-Mel NPs were synthesized, characterized and then employed as a chemical priming agent in spearmint (Mentha spicata L.) plants 24 h prior to salinity stress imposition. As expected, salt stress negatively affected morphophysiological attributes such as plant height, leaf number, leaf fresh weight, leaf dry weight, photosynthetic pigments, Fv/Fo, and Fv/Fm. On the other hand, stress-related attributes, such as content of proline, MDA and H2O2, as well as activity of APX and GP enzymes were increased in response to salt stress. However, adverse effects of salt stress were ameliorated with Mel and CTS-HPMC-Mel NP treatments by enhancing morphological traits, proline, antioxidant enzymatic activities, as well as content of dominant constituents of essential oil profile. It is worth noting that conjugated form of Mel with chitosan, in comparison with solo treatment of Mel, was more effective in combating stress effects. To our knowledge, this is the first report to demonstrate that engineered CTS-HPMC-Mel NPs could be applied as an innovative protective agent to mitigate the effects of salinity in crop plants.

Transgenerational effects of chromium stress at the phenotypic and molecular level in Arabidopsis thaliana.

In this study, we describe the results obtained in a study of the transgenerational phenotypic effects of chromium (Cr) stress on the model plant species Arabidopsis thaliana. The F1 generation derived from parents grown under chronic and medium chronic stress showed significantly higher levels of the maximal effective concentration (EC50) compared with F1 plants generated from unstressed parents. Moreover, F1 plants from Cr-stressed parents showed a higher germination rate when grown in the presence of Cr. F1 plants derived from parents cultivated under chronic Cr stress displayed reduced hydrogen peroxide levels under Cr stress compared to controls. At lower Cr stress levels, F1 plants were observed to activate promptly more genes involved in Cr stress responses than F0 plants, implying a memory effect linked to transgenerational priming. At higher Cr levels, and at later stages, F1 plants modulated significantly fewer genes than F0 plants, implying a memory effect leading to Cr stress adaptation. Several bHLH transcription factors were induced by Cr stress in F1 but not in F0 plants, including bHLH100, ORG2 and ORG3. F1 plants optimized gene expression towards pathways linked to iron starvation response. A model of the transcriptional regulation of transgenerational memory to Cr stress is presented here, and could be applied for other heavy metal stresses.

Application of Biostimulants in Tomato Plants (Solanum lycopersicum) to Enhance Plant Growth and Salt Stress Tolerance.

Under the era of climate change, plants are forced to survive under increasingly adverse conditions. Application of biostimulants in plants is shown to mitigate the deleterious effects of abiotic stresses including salinity, enhancing plant tolerance and performance. The present study focuses on the effects of five biostimulants based on biocompost and biofertilizer compounds that have been applied to tomato plants grown in the presence (salt-stressed plants) or absence of salt stress (control plants). To study the beneficial effects of the biostimulants in tomato plants, a series of analyses were performed, including phenotypic and agronomic observations, physiological, biochemical and enzymatic activity measurements, as well as gene expression analysis (RT-qPCR) including genes involved in antioxidant defense (SlCu/ZnSOD, SlFeSOD, SlCAT1, SlcAPX), nitrogen (SlNR, SlNiR, SlGTS1) and proline metabolism (p5CS), potassium transporters (HKT1.1, HKT1.2), and stress-inducible TFs (SlWRKY8, SlWRKY31). Among all the biostimulant solutions applied to the plants, the composition of 70% biofertilizer and 30% biocompost (Bf70/Bc30) as well as 70% biocompost and 30% biofertilizer (Bc70/Bf30) formulations garnered interest, since the former showed growth promoting features while the latter displayed better defense responses at the time of harvesting compared with the other treatments and controls. Taken together, current findings provide new insight into the beneficial effects of biostimulants, encouraging future field studies to further evaluate the biostimulant effects in plants under a real environment which is compromised by a combination of abiotic and biotic stresses.

Temperature and Humidity Sensitivity of Polymer Optical Fibre Sensors Tuned by Pre-Strain.

Polymer optical fibre Bragg grating (POFBG) sensors are of high interest due to their enhanced fracture toughness, flexibility in bending, and sensitivity in stress and pressure monitoring applications compared to silica-based sensors. The POFBG sensors can also detect humidity due to the hydrophilic nature of some polymers. However, multi-parameter sensing can cause cross-sensitivity issues in certain applications if the temperature and humidity measurements are not adequately compensated. In this work, we demonstrate the possibility of selectively tuning sensors' temperature and humidity sensitivities to the desired level by applying a certain amount of fibre pre-strain. The temperature sensitivity of POFBG sensors fabricated in perfluoropolymers (CYTOP) can be selectively tuned from positive to negative values, having the option for insensitivity in specific temperature ranges depending on the amount of the applied pre-strain. The humidity sensitivity of sensors can also be changed from positive values to insensitivity. The importance of thermal annealing treatment of POFBG sensors for improved repeatability in temperature measurements is also reported. An array of 4 multiplexed POFBGs was fabricated, and each sensor was pre-strained accordingly to demonstrate the possibility of having targeted temperature and humidity sensitivities along the same fibre.

Online Gamma Radiation Monitoring Using Few-Mode Polymer CYTOP Fiber Bragg Gratings.

We investigated the gamma radiation response of fiber Bragg gratings (FBGs) inscribed in a few-mode polymer optical fiber. The fiber had a graded-index CYTOP core of 20 µm and XYLEX overclad of 250 µm in diameter. Four FBGs were exposed to gamma radiation during four irradiation sessions at a 5.3 kGy/h dose rate. The FBGs showed a linear Bragg wavelength shift with the received dose with a mean sensitivity of -3.95 pm/kGy at 43 °C. The increased temperature provides a rise in the sensitivity: it reached -10.6 pm/kGy at 58 °C. After irradiation, the FBGs showed partial recovery, which increased with the received dose. Furthermore, the FBG's reflection power decreased with the dose. This attenuation is mainly due to insertion losses caused by the radiation induced attenuation in the CYTOP fiber. Linear response to the received dose makes CYTOP FBGs attractive for gamma radiation dosimetry. However, temperature dependence of the sensitivity should be compensated in practical applications.

Comparative Study of γ- and e-Radiation-Induced Effects on FBGs Using Different Femtosecond Laser Inscription Methods.

This work presents an extensive, comparative study of the gamma and electron radiation effects on the behaviour of femtosecond laser-inscribed fibre Bragg gratings (FBGs) using the point-by-point and plane-by-plane inscription methods. The FBGs were inscribed in standard telecommunication single mode silica fibre (SMF28) and exposed to a total accumulated radiation dose of 15 kGy for both gamma and electron radiation. The gratings' spectra were measured and analysed before and after the exposure to radiation, with complementary material characterisation using Fourier transform infrared (FTIR) spectroscopy. Changes in the response of the FBGs' temperature coefficients were analysed on exposure to the different types of radiation, and we consider which of the two inscription methods result in gratings that are more robust in such harsh environments. Moreover, we used the FTIR spectroscopy to locate which chemical bonds are responsible for the changes on temperature coefficients and which are related with the optical characteristics of the FBGs.

Functionalized Magnetic Nanomaterials in Agricultural Applications.

The development of functional nanomaterials exhibiting cost-effectiveness, biocompatibility and biodegradability in the form of nanoadditives, nanofertilizers, nanosensors, nanopesticides and herbicides, etc., has attracted considerable attention in the field of agriculture. Such nanomaterials have demonstrated the ability to increase crop production, enable the efficient and targeted delivery of agrochemicals and nutrients, enhance plant resistance to various stress factors and act as nanosensors for the detection of various pollutants, plant diseases and insufficient plant nutrition. Among others, functional magnetic nanomaterials based on iron, iron oxide, cobalt, cobalt and nickel ferrite nanoparticles, etc., are currently being investigated in agricultural applications due to their unique and tunable magnetic properties, the existing versatility with regard to their (bio)functionalization, and in some cases, their inherent ability to increase crop yield. This review article provides an up-to-date appraisal of functionalized magnetic nanomaterials being explored in the agricultural sector.

Exogenous application of melatonin to plants, algae, and harvested products to sustain agricultural productivity and enhance nutritional and nutraceutical value: A meta-analysis.

Melatonin is produced by plants, algae, and animals. Worldwide studies show diverse positive effects of exogenous melatonin on plants, edible plant products, and algae, but the potential of melatonin to enhance food and feed systems through these positive effects remains largely unexplored. Through a meta-analysis of about 25,000 observations, we show for the first time that exogenous application of melatonin significantly increases crop productivity and yields, and enhances the nutritional and nutraceutical value of edible plant products and algae by regulating diverse biological functions. We demonstrate that melatonin can improve plants, edible plant products, and algae under various current climate change scenarios, environmental pollution factors, and other stresses by about 7% to nearly 30%, on average, depending on the stressor. We also analyze various technical/methodological factors influencing the desired outcomes and identify conditions that offer optimal enhancement. We show that the positive effect of melatonin on plants and edible plant products varies among species, genera, and families, and strongly depends on the concentration of melatonin and treatment duration. The effect of melatonin is slightly lower on the monocot clade Commelinids than on the eudicot clades Asterids and Rosids. We also show that its stimulatory effect on plants depends on cultivation system, with a larger effect obtained in hydroponic systems. However, it does not depend on application stage (seed or vegetative), application route (foliage, roots, or seed), and whether the cultivation system is ex vivo or in vivo. This is the first meta-analysis examining the effects of melatonin on plants, edible plant products, and algae, and offers a scientific and technical roadmap facilitating sustainable food and feed production through the application of exogenous melatonin.

Long period grating in a multimode cyclic transparent optical polymer fiber inscribed using a femtosecond laser.

In this Letter, we report, to the best of our knowledge, the first inscription of long period gratings (LPGs) in a multimode cyclic transparent optical polymer (CYTOP) fiber using a femtosecond laser inscription method. The LPG was inscribed directly in the center of the fiber core, tailored for operation at 1560 nm. The CYTOP-LPG was characterized in transmission, and its response for relative humidity and temperature was measured. The humidity measurements, to the best our knowledge, are the first for a POF-LPG, whereas the temperature sensitivity is significantly higher than reported in other works. In addition, dynamic mechanical measurements were performed comparing the mechanical characteristics of the laser exposed sections of the polymer fiber, where the LPG was inscribed, with the unexposed regions.

Cone-Beam Computed Tomography Analysis of the Prevalence, Length, and Passage of the Anterior Loop of the Mandibular Canal.

When placing implants in the anterior mandible, it is important to avoid damaging the mandibular nerve and its terminal extensions. The objective of this study was to determine the prevalence, length, and passage of the anterior loop of the mandibular canal, as well as the quantity of alveolar bone that is coronal to the canal, to help with implant placement in the anterior mandible. Cone-beam computerized tomography (CBCT) scans of 124 patients with 248 hemi-sections were evaluated. Anterior loop prevalence was determined using reconstructed panoramic and cross-sectional views; length was measured as the distance between the most mesial aspect of the mental foramen to the most mesial aspect of the anterior loop on cross-sectional views. The bucco-lingual position of the anterior loop inside the mandible and the apico-coronal dimensions of the alveolar bone above it were measured on cross-sectional views to determine the passage of the anterior loop and the bone available coronally, respectively. The effects of sex, age, side, and dentate status on the prevalence and length of the anterior loop were analyzed statistically. Prevalence of the anterior loop at the patient and hemi-section levels was 25% and 24%, respectively, and its median length was 1.63 mm (range, 0.52-3.92 mm). The anterior loop was apical to the mental foramen and mostly located within the buccal or middle one-third of the alveolar ridge, with an average height of coronal alveolar bone of 17.12 mm. Sex, age, side, and dentate status did not affect anterior loop prevalence and length. In conclusion, because of great variation, a case-by-case CBCT evaluation of the anterior loop is necessary before placing implants in the anterior mandible.

A Multicenter Retrospective Clinical Study with Up-to-5-Year Follow-up Utilizing a Method that Enhances Bone Density and Allows for Transcrestal Sinus Augmentation Through Compaction Grafting.

PURPOSE: To evaluate the effectiveness and predictability of a novel biomechanical, minimally invasive bone instrumentation technique that enhances bone density through compaction grafting, called osseous densification, and allows for transcrestal sinus membrane elevation and augmentation with simultaneous implant placement. MATERIALS AND METHODS: Patients who were consecutively treated with the bone densification and transcrestal sinus augmentation technique and were followed up in three treatment centers between May 2012 and September 2017 were included in this retrospective study. The summary statistics are presented as means for continuous variables and percentages for categorical variables. RESULTS: In total, 222 patients with 261 implants were included in the final clinical analysis. The included follow-up period ranged from 6 to 64 months with a mean of 35 months. The subsinus residual bone height at baseline was 5.4 mm (SD: 1.9). Following the sinus augmentation, a significant vertical increase of 7 mm (SD: 2.49) was observed. No sinus membrane perforations and no late implant failures were observed from 6 up to 64 months follow-up, yielding a cumulative implant survival rate of 97%. CONCLUSION: This osseous densification technique for maxillary implant site preparation with transcrestal sinus augmentation and simultaneous implant placement led to favorable clinical outcomes with up to 64 months of follow-up.

Ridge Preservation Procedures after Tooth Extractions: A Systematic Review.

BACKGROUND: The purpose of this systematic review was to accurately assess the procedural success of ridge preservation technique through the application of strict inclusion and exclusion criteria. DATA SOURCES: A methodical search of PubMed of the US National Library of Medicine and the Cochrane Central Register of Controlled Trials was conducted for applicable articles. Only randomized controlled trials comparing ridge preservation treatment with a nongrafting control, ten-subject minimum sample size, and three or more months of follow-up were included in our study. TYPES OF STUDIES REVIEWED: In a screening between January 1980 and September 2017, articles meeting predetermined criteria were further examined in a qualitative data analysis. A thorough search of the databases provided 1876 articles. Of these records, 174 were assessed for eligibility through the systematic employment of inclusion and exclusion criteria. RESULTS: Two records were appropriate for further data analysis. One study used a mixture of a deproteinized cancellous bovine bone and porcine collagen fibers in a block form (DBB/CF), while the other study used leukocyte-platelet-rich fibrin (L-PRF). The use of DBB/CF reduced the magnitude of vertical bone resorption, yet the study showed high risk of bias. The use of L-PRF reduced the magnitude of both the horizontal and vertical crestal bone resorption; however, the low sample size created wide standard deviations between the test and control groups. Inherent weaknesses were present in both studies. Through methodical analysis of both records, the dissimilarities prevented the conduction of a meta-analysis. IMPLICATIONS OF KEY FINDINGS: Within the limitations of this systematic review, L-PRF reduced the magnitude of vertical and horizontal bone resorption, which places L-PRF as a potential material of choice for ridge preservation procedures. CONCLUSIONS: Within the limitations and weaknesses of both studies, the use of DBB/CF prevented the vertical crestal bone resorption while the L-PRF prevented both the horizontal and vertical crestal bone resorption. More randomized controlled clinical trials are needed to eliminate all the confounding factors, which bias the outcome of ridge preservation techniques.

Surface plasmon resonance sensing in gaseous media with optical fiber gratings.

Surface plasmon resonance excitation with optical fiber gratings has been typically studied in aqueous solutions. This work describes the procedure to excite a plasmon wave in gaseous media and perform refractive index measurements in these environments. Grating photo-inscription with 193 nm excimer laser radiation allows us to obtain slightly tilted fiber Bragg gratings exhibiting a cladding mode resonance comb along several hundreds of nanometers. Their refractive index sensitive range extends from gases to liquids, so operation in both media is compared. We demonstrate that the thickness of the metal coating required for surface plasmon excitation in gases is roughly one third of the one usually used for liquids. The developed platforms exhibit a temperature insensitive response of 78 nm/RIU when tested with different gases.

Higher-order cladding mode excitation of femtosecond-laser-inscribed tilted FBGs.

We study the modal behavior of plane-by-plane femtosecond laser fabricated tilted fiber Bragg gratings (FBGs). The focus is on the differential strain and temperature sensitivities between the cladding mode resonances of an nth grating order and those of the (n-i)th orders (with i=1-n), which are collocated in the same wavelength range. Whereas the Bragg mode exhibits an axial strain sensitivity of 1.2 pm/µÏµ, we experimentally show that the strain sensitivity of ultrahigh-order cladding modes is negative and at -1.99 pm/µÏµ in the same spectral window. Using a finite element mode solver, the modal refractive index value is computed to be well below 1, thus confirming that these modes, in reality, are leaky modes.