Chemogenetic Activation of RFRP Neurons Reduces LH Pulse Frequency in Female but not Male Mice.

Context: The neuropeptide RFRP-3 (RFamide-related peptide-3) is thought to play a role in the negative regulation of fertility. However, the exogenous administration of RFRP-3 yields varying results depending on the dose and route of administration, sex of the subject, and many other variables. Manipulation of in vivo neuronal activity using DREADDs (designer receptor exclusively activated by designer drugs) technology enables investigation of cell type-specific neuronal activation in a manner that better reflects endogenous neuronal activity. Objective: To test the effects of RFRP neuronal activation on pulsatile luteinizing hormone (LH) secretion. Methods: We generated mice expressing the stimulatory hM3Dq designer receptor exclusively in RFRP cells using 2 different Cre-loxP-mediated approaches: (1) we bred mice to express hM3Dq in all Rfrp-Cre-expressing cells, including some that transiently expressed Rfrp-Cre neonatally (RFRP × hM3Dq mice), and (2) we stereotaxically injected Cre-dependent hM3Dq into the dorsomedial nucleus of RFRP-Cre mice to drive hM3Dq expression exclusively in a subpopulation of adult Rfrp-Cre neurons (RFRP-AAV-hM3Dq mice). We then investigated the effects of acute hM3Dq activation on LH pulse frequency in RFRP × hM3Dq mice, RFRP-AAV-hM3Dq mice, and their respective controls. Results: In both female RFRP × hM3Dq and RFRP-AAV-hM3Dq mice, chemogenetic activation of Cre-driven hM3Dq led to a significant 35% to 50% reduction in LH pulse frequency compared with controls, while no differences in pulse amplitude or mean LH concentration were observed. In marked contrast, RFRP activation did not cause any changes to LH pulse dynamics in male mice. Conclusions: These data show for the first time that activation of neurons that have expressed Rfrp, or of a subset of adult RFRP neurons, can independently suppress LH pulsatility in female, but not male mice.

The impact of health and environmental messaging with and without product filtering in complex retail markets: the case of pulses.

Introduction: Multiple barriers exist to healthy and environmentally sustainable food choices. Limited consumer understanding of the health and environmental implications of food choices complicates their abilities to make choices that lead to desired outcomes. The complexity of the retail environment itself may crowd out less immediate motivations to address health or environment. Even if consumers understand general impacts of food choices on health and environmental outcomes, there may be non-negligible time and search costs to identifying the products that meet consumers' needs. In many food categories, the foods containing attributes that help achieve health and sustainability outcomes may represent a small percentage of available products. In this research, we examine the case of pulses-beans, chickpeas, lentils, and dry peas. Pulses are nutritious and have a low environmental impact. However, consumption of pulses in the US is quite low, which may be attributable to low consumer knowledge of pulse benefits, as well as difficulty of identifying pulse products in retail environments. Methods: In this research, we examine the choice of pulse-based foods in three conditions: (1) a control condition, (2) a messaging condition communicating the health and environmental benefits of pulse products, and (3) a paired messaging condition with a choice environment intervention that allows respondents to choose to filter products to those that contain pulses. Participants selected a food item from each of six food categories. Results: We find slight, but significant, increases in pulse choice in the messaging only condition relative to the control condition, but dramatic and highly significant increases when participants can filter the products to easily view pulse products. We also find evidence for knowledge being a barrier to healthy/sustainable food choice. Participants exposed to the messaging were more likely to view pulses as environmentally beneficial, and less likely to report that they did not know the health or environmental impacts of pulse foods. Discussion: We find that paired messaging and filtering interventions significantly increase the choice of pulse-based foods, which offer both human health and sustainability benefits.

Lentils based pasta affect satiation, satiety and food intake in healthy volunteers.

Plant-based diets represent a valid strategy to improve human health and increase food sustainability. The availability of legume-based products, a good source of proteins and fibers, could help consumers to promote healthy dietary patterns. The aim of this study was to examine the impact of different legume-based pastas on energy intake and appetite in healthy volunteers. Four ad libitum (protocol 1) and iso-caloric pre-load meals (protocol 2) were tested using a randomized repeated measure design. The test meals consisted of lentils pasta (LP), chickpeas pasta (CP); durum wheat pasta (DWP) and gluten free pasta (GFP), served with tomato sauce. Protocol 1: the ad libitum lunch meal was consumed then EI registered. Protocol 2: subjective appetite was assessed by visual analogue scale before and after the pre-load meal for 2 h until an ad libitum buffet was served to assess EI. Twenty (age: 39.2 ± 8.41 years; BMI: 23.4 ± 3.4 kg/m2) and 40 (age: 42.6 ± 8.7 years; BMI: 23.8 ± 4.2 kg/m2) healthy subjects were respectively recruited for each protocol. ANCOVA analysis showed an overall effect of meals and sex on EI within meal and at the subsequent meal, resulting in a lower EI after LP compared to DWP (p < 0.05). Appetite sensations were significantly influenced solely after the pre-load meal, where repeated measures ANCOVA showed increased post-prandial satiety after LP and CP (p < 0.05) compared to DWP in females, whereas a reduction in desire to eat and higher fullness was found following LP compared to the other meals in both sexes (p < 0.05). Overall, lentil-based pasta seemed to acutely affect EI both within and at the subsequent meal, especially in females. Consumption of legume-based pasta might enhance legume intake by modulating appetite feelings and increasing food sustainability. However, further studies are needed to support these results in the long-term and considering different target populations.

The CellFX Percutaneous Electrode System for Nanosecond Pulsed Field Ablation.

The purpose of this study was to demonstrate the safety and performance of the CellFX Percutaneous Electrode for delivering nanosecond pulsed field ablation (nsPFA) energy to soft tissues. Three different porcine tissue types were treated, namely, liver, kidney, and skeletal muscle, at treatment levels of three times greater than clinical treatment levels. The histological characteristics of the ablation zone for each of these tissues compared with that of radiofrequency (RF) ablation on day 0 and 2 days post-treatment. Ablation zone dimensions were measured during gross necropsy after tetrazolium chloride staining and compared between the nsPFA and RF groups at 2 days post-ablation. The CellFX system successfully achieved ablation and necrosis of all treatment sites in all target tissues. No evidence of thermal effects or collagen degeneration was found at any of the nsPFA treatment sites. Overall systemic tolerability was evidenced by the absence of clinically significant changes in urinalysis and serum chemistry before and after treatments.

Selective depletion of kisspeptin neurons in the hypothalamic arcuate nucleus in early juvenile life reduces pubertal LH secretion and delays puberty onset in mice.

Puberty is the critical developmental transition to reproductive capability driven by the activation of gonadotropin-releasing hormone (GnRH) neurons. The complex neural mechanisms underlying pubertal activation of GnRH secretion still remain unknown, yet likely include kisspeptin neurons. However, kisspeptin neurons reside in several hypothalamic areas and the specific kisspeptin population timing pubertal onset remains undetermined. To investigate this, we strategically capitalized on the differential ontological expression of the Kiss1 gene in different hypothalamic nuclei to selectively ablate just arcuate kisspeptin neurons (aka KNDy neurons) during the early juvenile period, well before puberty, while sparing RP3V kisspeptin neurons. Both male and female transgenic mice with a majority of their KNDy neurons ablated (KNDyABL) by diphtheria toxin treatment in juvenile life demonstrated significantly delayed puberty onset and lower peripubertal LH secretion than controls. In adulthood, KNDyABL mice demonstrated normal in vivo LH pulse frequency with lower basal and peak LH levels, suggesting that only a small subset of KNDy neurons is sufficient for normal GnRH pulse timing but more KNDy cells are needed to secrete normal LH concentrations. Unlike prior KNDy ablation studies in rats, there was no alteration in the occurrence or magnitude of estradiol-induced LH surges in KNDyABL female mice, indicating that a complete KNDy neuronal population is not essential for normal LH surge generation. This study teases apart the contributions of different kisspeptin neural populations to the control of puberty onset, demonstrating that a majority of KNDy neurons in the arcuate nucleus are necessary for the proper timing of puberty in both sexes.

Pulse crops: nutrient density, affordability, and environmental impact.

Introduction: Sustainable foods need to be nutrient-rich, affordable, environmentally friendly, and socially acceptable. Pulses, which include beans, lentils, chickpeas, and dried peas are a food group that can fit all those criteria. Methods: These concepts were tested serially using nutrient profiling methods that focused on protein and were extended to include food prices, greenhouse gas emissions, and energy demand. The present sustainability analyses were based on the US Department of Agriculture (USDA) nutrient composition and food prices data. Environmental impact data came from life cycle assessments (LCA). First, the USDA Protein Foods Group was disaggregated into animal and plant proteins. Plant proteins were separated into pulses, soy products, and nuts and seeds. Results: Pulses were among the lowest-cost protein sources (per 100 g and per 100 kcal) and had the lowest greenhouse gas emissions GHGE and energy demand. Pulses were among the most sustainable foods when monetary and energy costs were expressed per 50 g of protein (equivalent to 100% DV). Pulses scored well on the Nutrient Rich Food (NRF9.3) nutrient profiling system and on the related Affordable Nutrition Index that assessed nutrient density per penny. Discussion: Pulses are a source of low-cost plant-based protein and a variety of priority vitamins and minerals, have low carbon footprint and energy demand, and are a valued culinary ingredient across diverse regions and cultures. As dietary guidance turns to plant-based diets, pulses need to be integrated into the global sustainability framework.

Impact of Sprouted Chickpea Grits and Flour on Dough Rheology and Bread Features.

This study investigated the effects of incorporating sprouted chickpeas, at a 25% enrichment level, into bread production as either grits (90% of particles ≥500 µm) or flour (90% of particles ≤250 µm). The focus was to investigate the role of particle size on dough and bread. In addition to the functional, mixing and pasting properties of ingredients, gluten aggregation, mixing, extensional, leavening, and pasting properties of the blends were assessed during bread-making, as well as bread volume and texture. Chickpea particle size influenced water absorption capacity (1.8 for grits vs. 0.75 g/g for flour) and viscosity (245 for grits vs. 88 BU for flour), with flour showing a greater decrease in both properties. With regard to dough properties, dough development time (16.6 vs. 5.3 min), stability (14.6 vs. 4.6 min), and resistance to extension (319 vs. 235 BU) was higher, whereas extensibility was lower (105 vs. 152 mm) with grits, compared to flour. During bread-making, grits resulted in a higher specific volume (2.5 vs. 2.1 mL/g) and softer crumb (6.2 vs. 17.4 N) at all the considered storage times. In conclusion, sprouted chickpea grits can be effectively used as a new ingredient in bread-making favouring the consumption of chickpea, without compromising product quality.

Calibration-free whole-brain CEST imaging at 7T with parallel transmit pulse design for saturation homogeneity utilizing universal pulses (PUSHUP).

PURPOSE: Chemical exchange saturation transfer (CEST) measurements at ultra-high field (UHF) suffer from strong saturation inhomogeneity. Retrospective correction of this inhomogeneity is possible to some extent, but requires a time-consuming repetition of the measurement. Here, we propose a calibration-free parallel transmit (pTx)-based saturation scheme that homogenizes the saturation over the imaging volume, which we call PUlse design for Saturation Homogeneity utilizing Universal Pulses (PUSHUP). THEORY: Magnetization transfer effects depend on the saturation B 1 rms $$ {\mathrm{B}}_1^{\mathrm{rms}} $$ . PUSHUP homogenizes the saturation B 1 rms $$ {\mathrm{B}}_1^{\mathrm{rms}} $$ by using multiple saturation pulses with alternating B 1 $$ {\mathrm{B}}_1 $$ -shims. Using a database of B 1 $$ {\mathrm{B}}_1 $$ maps, universal pulses are calculated that remove the necessity of time-consuming, subject-based pulse calculation during the measurement. METHODS: PUSHUP was combined with a whole-brain three-dimensional-echo planar imaging (3D-EPI) readout. Two PUSHUP saturation modules were calculated by either applying whole-brain or cerebellum masks to the database maps. The saturation homogeneity and the group mean CEST amplitudes were calculated for different B 1 $$ {\mathrm{B}}_1 $$ -correction methods and were compared to circular polarized (CP) saturation in five healthy volunteers using an eight-channel transmit coil at 7 Tesla. RESULTS: In contrast to CP saturation, where accurate CEST maps were impossible to obtain in the cerebellum, even with extensive B 1 $$ {\mathrm{B}}_1 $$ -correction, PUSHUP CEST maps were artifact-free throughout the whole brain. A 1-point retrospective B 1 $$ {\mathrm{B}}_1 $$ -correction, that does not need repeated measurements, sufficiently removed the effect of residual saturation inhomogeneity. CONCLUSION: The presented method allows for homogeneous whole-brain CEST imaging at 7 Tesla without the need of a repetition-based B 1 $$ {\mathrm{B}}_1 $$ -correction or online pulse calculation. With the fast 3D-EPI readout, whole-brain CEST imaging with 45 saturation offsets is possible at 1.6 mm resolution in under 4 min.

Steroid pulse therapy in idiopathic nephrotic syndrome in the era of modern immunosuppressive treatment-still up to date?

BACKGROUND: Intravenous steroid pulses (SP) are successfully used for the treatment of patients with idiopathic nephrotic syndrome (INS) resistant to oral prednisone. METHODS: We performed a retrospective analysis of all patients in the three pediatric nephrology centers of the Paris region from 2002 to 2022 who were resistant to a 30-day course of oral prednisone and who received SP for their first INS flare and analyzed their disease course over 4 years. RESULTS: Forty-seven patients (17 girls), median age 3.4 years, were analyzed. Of them, 68% reached remission within 7 days of SP. No significant short-term side effects were noted. Half of the patients started immunosuppressive treatment immediately after their first remission and 62% of them relapsed at least once, whereas all the patients who did not receive immunosuppressive treatment since their first remission relapsed. Among the SP-sensitive patients, 75% needed calcineurin inhibitor (CNI) or B-cell depletion during their disease course to achieve stable remission. Forty-two percent of the whole cohort received B-cell-depleting agents. Among the 15 SP-resistant patients, all received CNI. Twelve/fifteen patients reached remission. After 4 years, 68% among the SP-sensitive patients and 87% of SP-resistant patients still had an active disease. CONCLUSIONS: SP are helpful to obtain rapid remission in pediatric INS patients resistant to oral steroids. However, as most SP-sensitive patients need immunosuppressive drugs, mainly CNI and B-cell-depleting agents it could be interesting to discuss the possibility to start CNI directly after the 30-day course of prednisone instead of SP.

Impact of a Pulse-Enriched Human Cuisine on Functional Attributes of the Gut Microbiome Using a Preclinical Model of Dietary-Induced Chronic Diseases.

Introducing grain legumes, i.e., pulses, into any food pattern effectively increases dietary fiber and other bioactive food components of public health concern; however, the impact depends on the amount consumed. Given the convergence of preclinical and clinical data indicating that intake of at least 300 g (1.5 cup) of cooked pulse per day has clinically observable benefit, the feasibility for a typical consumer was demonstrated by creation of a fourteen-day menu plan that met this criterion. This menu plan, named Bean Cuisine, was comprised of a combination of five cooked pulses: dry beans, chickpeas, cowpeas, dry peas, and lentils. As reported herein, the impact of each menu day of the fourteen-day plan on gut microbial composition and predicted function was evaluated in female C57BL/6J mice, a strain commonly used in studies of metabolic dysfunction-associated chronic diseases. We report that pulse-related effects were observed across a wide variety of food item combinations. In comparison to a pulse-free human cuisine, all pulse menu days enriched for a gut ecosystem were associated with changes in predicted metabolic pathways involving amino acids (lysine, tryptophan, cysteine), short-chain fatty acids (butyrate, acetate), and vitamins (B1, B6, B9, B12, K2) albeit via different combinations of microbiota, according to the PICRUSt2 estimates. The predicted metabolic functions correlating with the various pulses in the menus, indicate the value of a food pattern comprised of all pulse types consumed on a regular basis. This type of multi-pulse food pattern has the potential to enhance the taxonomic and functional diversity of the gut microbiome as a means of strengthening the resilience of the gut ecosystem to the challenges associated with the daily activities of living.

Enhanced Cognition and Modulation of Brain Connectivity in Mild Neurocognitive Disorder: The Promise of Transcranial Pulse Stimulation.

Existing pharmacological treatments for mild neurocognitive disorder (NCD) offer limited effectiveness and adverse side effects. Transcranial pulse stimulation (TPS) utilizing ultrashort ultrasound pulses reaches deep brain regions and may circumvent conductivity issues associated with brain stimulation. This study addresses the gap in TPS research for mild NCD during a critical intervention period before irreversible cognitive degradation. Our objective was to explore the effectiveness and tolerability of TPS in older adults with mild NCD. In an open-label study, 17 older adults (including 10 females and 7 males) with mild NCD underwent TPS for two weeks with three sessions per week. Cognitive evaluations and fMRI scans were conducted pre- and post-intervention. The results indicated changes in functional connectivity in key brain regions, correlating with cognitive improvement at B = 0.087 (CI, 0.007-0.167; p = 0.038). However, cortical thickness measurements showed no significant differences. Here we show that TPS can enhance cognitive function within mild NCD. This proof-of-concept study suggests that TPS has potential as a non-invasive therapy used to attenuate cognitive decline, encouraging further investigation in larger randomized trials. The findings could influence clinical practice by introducing TPS as an adjunctive treatment option and potentially impact policy by promoting its inclusion in new treatment strategies for mild NCD.

Surface Coloring and Plasmonic Information Encryption at 50000 dpi Enabled by Direct Femtosecond Laser Printing.

Femtosecond (fs) laser pulses drive matter into a highly nonequilibrium state, allowing precise sculpturing of irradiated surface sites with sophisticated nanomorphologies. Here, we used fs-laser patterning to create diverse plasmonic morphologies on the top Au layer of the metal-insulator-metal sandwich. Mutual action of laser-driven thermomechanical effects and ultrafast solid-to-liquid transition allows control of the morphology resulting in pronounced surface reflectivity modulation, i.e., in a structural color effect. This enables template-free high-resolution color printing at a superior lateral resolution up to 50000 dots per inch and facile tunability of the color tone and saturation. Moreover, precise control over the orientation of the printed nanostructures within subwavelength lattices allows modulation of their local plasmonic response encrypting the optical information within the colorful images. The hidden information can be unveiled using a facile cross-polarized optical visualization scheme, rendering the proposed method with extra modalities combining high resolution information encryption, coloring, and security labeling.

Shot-Noise Limited Nonlinear Optical Imaging Excited With GHz Femtosecond Pulses and Denoised by Deep-Learning.

Multiphoton fluorescence microscopy excited with femtosecond pulses at high repetition rates, particularly in the range of 100's MHz to GHz, offers an alternative solution to suppress photoinduced damage to biological samples, for example, photobleaching. Here, we demonstrate the use of a U-Net-based deep-learning algorithm for suppressing the inherent shot noise of the two-photon fluorescence images excited with GHz femtosecond pulses. With the trained denoising neural network, the image quality of the representative two-photon fluorescence images of the biological samples is shown to be significantly improved. Moreover, for input raw images with even SNR reduced to -4.76 dB, the trained denoising network can recover the main image structure from noise floor with acceptable fidelity and spatial resolution. It is anticipated that the combination of GHz femtosecond pulses and deep-learning denoising algorithm can be a promising solution for eliminating the trade-off between photoinduced damage and image quality in nonlinear optical imaging platforms.

Development of a Miniaturized 2-Joule Pulsed Plasma Source Based on Plasma Focus Technology: Applications in Extreme Condition Materials and Nanosatellite Orientation.

Plasma focus devices represent a class of hot and dense plasma sources that serve a dual role in fundamental plasma research and practical applications. These devices allow the observation of various phenomena, including the z-pinch effect, nuclear fusion reactions, plasma filaments, bursts, shocks, jets, X-rays, neutron pulses, ions, and electron beams. In recent years, considerable efforts have been directed toward miniaturizing plasma focus devices, driven by the pursuit of both basic studies and technological advancements. In this paper, we present the design and construction of a compact, portable pulsed plasma source based on plasma focus technology, operating at the ~2-4 Joule energy range for versatile applications (PF-2J: 120 nF capacitance, 6-9 kV charging voltage, 40 nH inductance, 2.16-4.86 J stored energy, and 10-15 kA maximum current at short circuit). The components of the device, including capacitors, spark gaps, discharge chambers, and power supplies, are transportable within hand luggage. The electrical characteristics of the discharge were thoroughly characterized using voltage and current derivative monitoring techniques. A peak current of 15 kiloamperes was achieved within 110 nanoseconds in a short-circuit configuration at a 9 kV charging voltage. Plasma dynamics were captured through optical refractive diagnostics employing a pulsed Nd-YAG laser with a 170-picosecond pulse duration. Clear evidence of the z-pinch effect was observed during discharges in a deuterium atmosphere at 4 millibars and 6 kilovolts. The measured pinch length and radius were approximately 0.8 mm and less than 100 µm, respectively. Additionally, we explore the potential applications of this compact pulsed plasma source. These include its use as a plasma shock irradiation device for analyzing materials intended for the first wall of nuclear fusion reactors, its capability in material film deposition, and its utility as an educational tool in experimental plasma physics. We also show its potential as a pulsed plasma thruster for nanosatellites, showcasing the advantages of miniaturized plasma focus technology.

Towards shorter composite 180° refocusing pulses for NMR.

Novel composite 180° pulses are designed for use in nuclear magnetic resonance (NMR) and verified experimentally using solution-state 1H NMR spectroscopy. Rather than being constructed from 180° pulses (as in much recent work), the new composite pulses are constructed from 90° pulses, with the aim of finding sequences that are shorter overall than existing equivalents. The primary (but not exclusive) focus is on composite pulses that are dual compensated - simultaneously broadband with respect to both inhomogeneity of the radiofrequency field and resonance offset - and have antisymmetric phase schemes, such that they can be used to form spin echoes without the introduction of a phase error. In particular, a new antisymmetric dual-compensated refocusing pulse is presented that is constructed from ten 90° pulses, equivalent to just five 180° pulses.

Berberine-loaded nanoemulsions as a natural food preservative; the impact of femtosecond laser irradiation on the antibacterial activity.

There is a growing concern among food safety regulators, the food industry, and consumers about foodborne illnesses. To improve food safety and increase shelf life, it is necessary to use natural preservatives. Natural antimicrobials are safer than artificial preservatives because they can prevent microbial resistance while also meeting consumers' demands for healthier food. This study used Berberine to enhance the antibacterial activity of Satureja Khuzistanica essential oil nanoemulsions (SKEO NE) against Staphylococcus aureus (S. aureus) bacteria, making them a promising option as preservatives. Response Surface Methodology (RSM) was employed to determine the optimized Berberine loaded SKEO NE (Berberine/SKEO NE), resulting in a mean droplet size of 88.60 nm at 6.91, 3.21, and 0.08% w/w of surfactant, essential oil, and Berberine, respectively. Berberine utilization in SKEO NE has led to an increase in antibacterial activity. The nanoemulsion samples significantly ruptured the S. aureus bacterial cell membrane, rapidly discharging cell contents. The use of a microfluidic system in tandem based on the conventional approach significantly accelerated this process. Enhancing the interaction between nanodroplets and the bacterial membrane can be achieved through the nanoemulsification process of EOs, which involves modifying their surface characteristics. This enhancement is particularly pronounced when employing microfluidic systems due to their substantial contact surface area. We investigated the potential of using femtosecond laser irradiation at a wavelength of 1040 nm to augment the antibacterial action of nanoemulsions. The combined treatment of laser and nanoemulsions significantly increased the antibacterial effect of nanoemulsions by approximately 15% for each bacterium, suggesting the potential utility of this treatment to bolster the antibacterial activity of nanoemulsions. Bacteria were trapped using optical tweezers for up to 20 min, with bacterial destruction observed starting at 3 min and exhaustive destruction evident after 20 min.

Femtosecond Laser Ablation and Delamination of Functional Magnetic Multilayers at the Nanoscale.

Laser nanostructuring of thin films with ultrashort laser pulses is widely used for nanofabrication across various fields. A crucial parameter for optimizing and understanding the processes underlying laser processing is the absorbed laser fluence, which is essential for all damage phenomena such as melting, ablation, spallation, and delamination. While threshold fluences have been extensively studied for single compound thin films, advancements in ultrafast acoustics, magneto-acoustics, and acousto-magneto-plasmonics necessitate understanding the laser nanofabrication processes for functional multilayer films. In this work, we investigated the thickness dependence of ablation and delamination thresholds in Ni/Au bilayers by varying the thickness of the Ni layer. The results were compared with experimental data on Ni thin films. Additionally, we performed femtosecond time-resolved pump-probe measurements of transient reflectivity in Ni to determine the heat penetration depth and evaluate the melting threshold. Delamination thresholds for Ni films were found to exceed the surface melting threshold suggesting the thermal mechanism in a liquid phase. Damage thresholds for Ni/Au bilayers were found to be significantly lower than those for Ni and fingerprint the non-thermal mechanism without Ni melting, which we attribute to the much weaker mechanical adhesion at the Au/glass interface. This finding suggests the potential of femtosecond laser delamination for nondestructive, energy-efficient nanostructuring, enabling the creation of high-quality acoustic resonators and other functional nanostructures for applications in nanosciences.

Subnanosecond visible two-stage optical parametric generator and amplifier based on MgO:PPLN and LBO crystals at strong pump depletion.

Theoretical and experimental investigation of two-stage optical parametric generator based on magnesium oxide doped periodically poled lithium niobate (MgO:PPLN) crystal and optical parametric amplifier based on lithium triborate (LBO) crystal is presented. The first stage crystal was pumped by the subnanosecond fundamental harmonic at 1064 nm wavelength. In the theoretical description, the input signal and idler photons are described by the quantum model and their further amplification is tracked by simulating the nonlinear coupling equations. Such description allows the analysis of pulsed beam evolution during the propagation in the nonlinear crystal under strong pump depletion regime. The second stage crystal was seeded by the output signal wave of the first stage and pumped by the third harmonic of the laser radiation. Experimentally, tuning in the visible wavelength ranges and high pulse power (up to 20 mW at 475 nm wavelength) were achieved.

Lens Fragmentation with Picosecond Laser Pulses After Artificial Cataract Induction with Microwaves.

Objectives: In this work we demonstrate the first laboratory study results of lens fragmentation with low-energy picosecond ultrashort laser pulses after artificial induction of cataract with microwave radiation on an ex vivo animal model. Background: This method will be evaluated with regard to the further development of lens fragmentation with novel ultrashort picosecond laser systems instead of ultrasonic phacoemulsification or the significantly more complex femtosecond laser fragmentation. Methods: As samples we used postmortem porcine eyes. The lenses were dissected and then irradiated in a microwave oven for artificial cataract induction. Subsequent computer-driven lens fragmentation was performed with a 12 ps, 1064 nm pulsed laser source with 100 µJ pulse energy, and 10 kHz pulse repetition rate. Results: Both the artificial cataract induction and the lens fragmentation were demonstrated. When inducing cataract, different degrees/stages of opaqueness and hardness could be achieved with different irradiation times and methods. The fragmentation with 12 ps pulses led to good results with regard to ablation depth and rate, especially for the softer lenses. Conclusions: As could be shown, low-energy picosecond ultrashort laser pulses are feasible for cataractous lens fragmentation on an ex vivo animal model with artificial cataract induction. Thus, this technique may influence future cataract surgeries by possibly being an alternative or extension to state-of-the-art methods. This will be evaluated with further tests and studies.

Replication of Radial Pulses Using Magneto-Rheological Fluids.

The radial pulse is a critical health marker with expanding applications in wearable technology. To improve these applications, developing a pulse generator that consistently produces realistic pulses is crucial for validation and training. The goal of this study was to design and test a cost-effective pulse simulator that can accurately replicate a wide range of age-dependent radial pulses with simplicity and precision. To this end, this study incorporated a magneto-rheological (MR) fluid device into a cam-based pulse simulator. The MR device, as a key component, enables pulse shaping without the need for additional cams, substantially reducing the cost and complexity of control compared with existing pulse simulators. To evaluate the performance of the MR pulse simulator, the root-mean-square (RMS) error criterion (less than 5%) was used to compare the experimentally obtained pulse waveform with the in vivo pulse waveform for specific age groups. After demonstrating that the MR simulator could produce three representative in vivo pulses, a parametric study was conducted to show the feasibility of the slope-based pulse-shaping method for the MR pulse simulator to continuously generate a range of age-related pulses.