Search Results (88)

Hollow microneedle (HMN) systems can deliver insulin with minimal pain, but most rely on external pumps that add bulk, cost, and failure modes. This paper reports the design, fabrication, and mechanical characterisation of a pump-free, refillable HMN patch that integrates a syringe-loadable, self-sealing reservoir and delivers by passive diffusion. A 3 × 4 array of side-orifice conical HMNs with a target height of 1 mm and a bore of 0.8 mm was stereolithography-printed in dental-grade resin and coupled to an elastic-grade resin septum that maintains a leak-free seal after repeated needle puncture. A surface-response design of experiments (DoE) probed wall thickness of 0.10–0.20 mm, post-cure time of 20–60 min, and temperatures of 35–80 °C. The microneedle characteristics include geometric fidelity, insertion into multilayer Parafilm, and axial compression to 150 N. All patches were printed with a hollow channel and side orifices with tips were slightly blunted. Relative to the original design, height undershoot was from −24.5% to −60.5% while base diameters were within −11% to +20%. Parafilm insertion exhibited a peak then force drop at about 0.22 mm displacement with 1.2–1.5 N pierced the first layer. It was found that about 90% of needles penetrated about 381 µm and more than 20% reached 635 µm. Patches withstood 150 N without fracture with strains of 9.7–15.6% and modulus of 8–48 MPa. ANOVA identified wall thickness as a significant factor, with curing temperature not being significant. Contour analysis defined an operating window near a 0.15 mm wall and about 40 min post-cure balancing dimensional fidelity and post-compression height retention. These results define a manufacturable path to compact, pump-free insulin patches with low insertion force and robust mechanics, opening a clinically scalable route to simpler everyday insulin therapy. Full article

Background/Objectives: Cinnamon leaves, an important source of the functional compound cinnamaldehyde (CA), have been shown to be effective in improving type II diabetes and Parkinson’s disease (PD) in rats following the incorporation of cinnamon leaf extract into a nanoemulsion. However, the effect of a cinnamon leaf extract nanoemulsion (CLEN) on improving Alzheimer’s disease (AD), the most prevalent type of dementia, remains unexplored. The objectives of this study were to determine functional compounds in cinnamon leaves by UPLC-MS/MS, followed by the preparation of a nanoemulsion and its byproducts to study their effects on AD and PD in rats. Methods: Oven-dried (60 °C for 2 h) cinnamon leaf powder and hydrosol, obtained by steam distillation of cinnamon leaf powder, were stored at 4 °C. After determination of basic composition (crude protein, crude fat, carbohydrate, moisture and ash) of cinnamon leaf powder, it was extracted with 80% ethanol with sonication at 60 °C for 2 h and analyzed for bioactive compounds by UPLC-MS/MS. Then, the CLEN was prepared by mixing cinnamon leaf extract rich in CA with lecithin, soybean oil, tween 80 and ethanol in an optimal ratio, followed by evaporation to form thin-film and redissolving in deionized water. For characterization, mean particle size, polydispersity index (PDI), zeta potential, encapsulation efficiency, and surface morphology were determined. Animal experiments were done by dividing 90 male rats into 10 groups (n = 9), with groups 2–8 being subjected to mini-osmotic pump implantation surgery in brain to infuse Amyloid-beta 40 (Aβ40) solution in groups 2–8 for induction of AD, while groups 9 and 10 were pre-fed respectively with cinnamon powder in water (0.5 g/10 mL) and in hydrosol for 4 weeks, followed by induction of AD as shown above. Different treatments for a period of 4 weeks included groups 1–9, with group 1 (control) and group 2 feeding with sterilized water, while groups 3, 4 and 5 were fed respectively with high (90 mg/kg), medium (60 mg/kg) and low (30 mg/kg) doses of cinnamon leaf extracts, groups 6, 7 and 8 fed respectively with high (90 mg/kg), medium (60 mg/kg) and low (30 mg/kg) doses of nanoemulsions, groups 9 and 10 fed respectively with 10 mL/kg of cinnamon powder in water and hydrosol (0.5 g/10 mL). Morris water maze test was conducted to determine short-term memory, long-term memory and space probing of rats. After sacrificing of rats, brain and liver tissues were collected for determination of Aβ40, BACE1 and 8-oxodG in hippocampi, and AchE and malondialdehyde (MDA) in cortices, antioxidant enzymes (SOD, CAT, GSH-Px) and MDA in both cortices and livers, and dopamine in brain striata by using commercial kits. Results: The results showed that the highest level of CA (18,250.7 μg/g) was in the cinnamon leaf powder. The CLEN was prepared successfully, with an average particle size of 17.1 nm, a polydispersity index of 0.236, a zeta potential of −42.68 mV, and high stability over a 90-day storage period at 4 °C. The Morris water maze test revealed that the CLEN treatment was the most effective in improving short-term memory, long-term memory, and spatial probe test results in AD rats, followed by the cinnamon leaf extract (CLE), powder in hydrosol (PH), and powder in water (PW). Additionally, both CLEN and CLE treatments indicated a dose-dependent improvement in AD rats, while PH and PW were effective in preventing AD occurrence. Furthermore, AD occurrence accompanied by PD development was demonstrated in this study. With the exception of the induction group, declines in Aβ40, BACE1, and 8-oxodG in the hippocampi and AchE and MDA in the cortices of rats were observed for all the treatments, with the high-dose CLEN (90 mg/kg bw) exhibiting the highest efficiency. The antioxidant enzyme activity, including that of SOD, CAT, and GSH-Px, in the cortices of rats increased. In addition, dopamine content, a vital index of PD, was increased in the striata of rats, accompanied by elevations in SOD, CAT, and GSH-Px and decreased MDA in rat livers. Conclusions: These outcomes suggest that the CLEN possesses significant potential for formulation into a functional food or botanical drug for the prevention and treatment of AD and/or PD in the future. Full article

Ground-source heat pumps (GSHPs), despite their high efficiencies, are still not as cost-effective as air-source heat pumps, especially in urban environments, due to the necessity of drilling/excavation. Integrating GSHPs into existing geo-structures, such as underground tunnels, can play a vital role in reducing the overall costs of GSHP systems and promoting their use in cities. Tunnels can be realized through artificial ground freezing (AGF) by using probes for circulating the freezing fluid, which are left in the ground once the tunnel is completed. The novelty of the present work lies in the proposal of a sustainable reuse of AGF probes as ground heat exchangers (GHEs). The idea of converting AGF probes is both sustainable and cost-effective for GSHPs, as it can reduce installation costs by eliminating the drilling/excavation process. A test was performed for the first time in the Piazza Municipio metro station in Naples, Southern Italy, where several AGF probes, initially used for the construction of two tunnels, have then been converted into GHEs. The probes have been connected to a testing device called the energy box. The experiments included testing the heat transfer in the recovered AGF probes through cooling and heating operations. This work presents a numerical simulation of a test that has been validated against experimental results. Full article

Diamond, widely used in optoelectronic devices, plays a crucial role in improving performance through studies of its electronic structure and optoelectronic response. This study combines computational methods and experiments for analysis. Density functional theory calculates the diamond’s band structure and refractive index, while the Keldysh formula determines the laser intensity at the critical plasma density by evaluating laser-induced free electron density. By integrating the coupled model with a multi-physics field associative assignment, the critical plasma length in the diamond is further simulated. Experimentally, pump-probe techniques examine the diamond’s response under varying pulse widths and energies. Results show that increasing laser energy extends both plasma and damage lengths. As pulse width increases, plasma length first decreases and then increases, while graphitization length shows the opposite trend. Experiments show that laser energy enhancement significantly expands the plasma morphology by enhancing the nonlinear ionization effect. When the pulse width exceeds the electron-lattice relaxation time, the lattice energy deposition triggers localized graphitization, which enhances the subsequent laser absorption, and the final plasma distribution shows a high spatial correlation with the graphitized regions. Full article

This paper presents a numerical and experimental investigation of stimulated Brillouin scattering (SBS) in a highly birefringent spun optical fiber. When subjected to bending, the variation in the state-of-polarization (SOP) of the pump and probe waves induces a periodic oscillation of the Brillouin gain, with a period equal to the elliptical birefringence of the fiber. The experiments were corroborated by numerical simulations, combining the coupled equations governing the SOP evolution in bent spun fibers, with a scalar SBS model valid for Brillouin optical frequency-domain analysis (BOFDA) sensors. Full article

This work provides theoretical calculations of fluorescence angular distribution and polarization within an XUV pump–XUV probe scheme designed for determining ultra-short lifetimes of highly charged heavy ions. The initial pumping leads to a non-zero alignment in the excited levels. After the probing stage, the anisotropies in angular distribution and polarization of subsequent fluorescence are significantly enhanced due to the existence of a previous alignment. Furthermore, two-photon sequential excitation from a ground state with zero angular momentum to a level with angular momentum one by two aligned linearly polarized photon beams is strictly prohibited by the selection rules and may be used as a diagnostic tool to determine beam misalignment. The present approach is based on the density matrix and statistical tensor framework. We provide the analytical form for the alignment parameters caused by successive photoexcitation either with linearly polarized photon beams, or with unpolarized photons. The analytical results can generally be used to compute angular distribution asymmetry parameters and linear polarization of subsequent fluorescence for a large array of atomic systems used in pump–probe experiments. Full article

High-precision magnetometers play a crucial role in ocean exploration, geophysical prospecting, and military and security applications. Installing them on human-occupied vehicle (HOV) platforms can greatly enhance ocean exploration capabilities and efficiency. However, most existing magnetometers suffer from low sensitivity and excessively large size. This study presents a high-sensitivity, miniaturized magnetometer based on cesium optically pumped probes. The designed magnetometer utilizes a three-probe design to eliminate the detection dead zone of the cesium optically pumped probe and enable three-dimensional magnetic detection. The proposed magnetometer uses a flux gate probe to detect the three-axis magnetic field and ensure that the probe does not enter the dead zone. The three probes can automatically switch by measuring the geomagnetic elements and real-time attitude of the HOV platform. This article primarily introduces the cesium three-probe optically pump, flux gate sensor, and automatic switching scheme design of the above-mentioned magnetometer. Moreover, it is proven through testing that the core indicators, such as the accuracy and sensitivity of the cesium three-probe optically pumped and flux gate sensor, reach international standards. Finally, the effectiveness of the automatic switching scheme proposed in this study is demonstrated through drone-mounted experiments. Full article

Previous studies reported that a mild, non-protein-denaturing, fever-like temperature increase induced the unfolded protein response (UPR) in mammalian cells. Our dSTORM super-resolution microscopy experiments revealed that the master regulator of the UPR, the IRE1 (inositol-requiring enzyme 1) protein, is clustered as a result of UPR activation in a human osteosarcoma cell line (U2OS) upon mild heat stress. Using ER thermo yellow, a temperature-sensitive fluorescent probe targeted to the endoplasmic reticulum (ER), we detected significant intracellular thermogenesis in mouse embryonic fibroblast (MEF) cells. Temperatures reached at least 8 °C higher than the external environment (40 °C), resulting in exceptionally high ER temperatures similar to those previously described for mitochondria. Mild heat-induced thermogenesis in the ER of MEF cells was likely due to the uncoupling of the Ca²⁺/ATPase (SERCA) pump. The high ER temperatures initiated a pronounced cytosolic heat-shock response in MEF cells, which was significantly lower in U2OS cells in which both the ER thermogenesis and SERCA pump uncoupling were absent. Our results suggest that depending on intrinsic cellular properties, mild hyperthermia-induced intracellular thermogenesis defines the cellular response mechanism and determines the outcome of hyperthermic stress. Full article

Pulsed lasers alter the optical properties of semiconductors and affect the photoelectric function of the photodetectors significantly, resulting in transient changes known as bleaching. Bleaching has a profound impact on the control and interference of photodetector applications. Experiments using pump–probe techniques have made significant contributions to understanding ultrafast carrier dynamics. However, there are few theoretical studies to the best of our knowledge. Here, carrier dynamic models for semiconductors and photodetectors are established, respectively, employing the rectified carrier drift-diffusion model. The pulsed laser bleaching effect on seven types of semiconductors and photodetectors from visible to long-wave infrared is demonstrated. Additionally, a continuous bleaching method is provided, and the finite-difference time-domain (FDTD) method is used to solve carrier dynamic theory models. Laser parameters for continuous bleaching of semiconductors and photodetectors are calculated. The proposed bleaching model and achieved laser parameters for continuous bleaching are essential for several applications using semiconductor devices, such as infrared detection, biological imaging, and sensing. Full article

The ability to study chemical dynamics on ultrafast timescales has greatly advanced with the introduction of X-ray free electron lasers (XFELs) providing short pulses of intense X-rays tailored to probe atomic structure and electronic configuration. Fully exploiting the full potential of XFELs requires specialized experimental endstations along with the development of techniques and methods to successfully carry out experiments. The liquid jet endstation (LJE) at the Linac Coherent Light Source (LCLS) has been developed to study photochemistry and biochemistry in solution systems using a combination of X-ray solution scattering (XSS), X-ray absorption spectroscopy (XAS), and X-ray emission spectroscopy (XES). The pump–probe setup utilizes an optical laser to excite the sample, which is subsequently probed by a hard X-ray pulse to resolve structural and electronic dynamics at their intrinsic femtosecond timescales. The LJE ensures reliable sample delivery to the X-ray interaction point via various liquid jets, enabling rapid replenishment of thin samples with millimolar concentrations and low sample volumes at the 120 Hz repetition rate of the LCLS beam. This paper provides a detailed description of the LJE design and of the techniques it enables, with an emphasis on the diagnostics required for real-time monitoring of the liquid jet and on the spatiotemporal overlap methods used to optimize the signal. Additionally, various scientific examples are discussed, highlighting the versatility of the LJE. Full article

A time-differential (TD) Brillouin optical correlation domain analysis (BOCDA) sensor system was applied to measure the Brillouin gain spectrum of a 1 km long sensing optical fiber. The optical delay line used in all BOCDA measurement systems was eliminated in the TD-BOCDA system by using a bit-delayed modulation relationship between the probe and pump lightwaves. These lightwaves were phase modulated using 2¹⁶-1 pseudo-random binary sequence codes at 5 Gbps. A 2 cm dispersion-shifted fiber placed at the end of the 1 km optical fiber was distinctly identified by the Brillouin frequency extracted from the Brillouin gain spectrum measurement. To investigate the measurement stability of the TD-BOCDA system, experiments were conducted under two different pumping conditions. A semiconductor optical amplifier (SOA) and an intensity modulator (MOD) were compared for the pump chopper used in the TD-BOCDA system to detect the extinction ratio of the pump and the resulting noise in the Brillouin gain measurement. The stability of the Brillouin frequency measurement from the Brillouin gain spectrum in the TD-BOCDA system was investigated by increasing the average value of the measurement using either the SOA or MOD. The repeated-measurement deviation of the system with the SOA was only half of the deviation observed in the system with the MOD. The performance of TD-BOCDA is equivalent to or better than that of conventional BOCDAs in terms of measurement reliability. Moreover, TD-BOCDA is free from the drawbacks of traditional BOCDA, which uses time-delayed fibers and varies the bit rates. Full article

An optical frequency comb (OFC) generator based on an electro-optic Talbot laser and cross-phase modulation (XPM) in a high nonlinear fiber (HNLF) is designed and demonstrated. The Talbot laser is an electro-optic frequency shifting loop that is used to produce repetition rate-multiplied pulses, and these pulses work as a pump signal that induces the XPM process in the HNLF to modulate the phase of a probe signal. At the output of the HNLF, OFCs with a multiplied line spacing can be generated. The effects of the pump power and the HNLF length on the performance of the generated OFCs are theoretically analyzed. In the experiments, the line spacing of the generated OFCs is multiplied to be 10 GHz, 15 GHz, and 20 GHz with a factor of 2, 3, and 4, respectively. The center of the OFCs is tuned in a 4 nm range by adjusting the wavelength of the probe signal. Full article

The high peak current of the electron beam was found to be the key parameter for the THz SASE FEL at the Photo Injector Test facility at DESY in Zeuthen (PITZ). A multipurpose bunch compressor was implemented at PITZ to expand the parameter space of proof-of-principle studies on the tunable high-power accelerator-based THz source for pump-probe experiments at the European XFEL. The magnetic chicane, consisting of four rectangular dipole magnets, is designed with a bending angle of 19 degrees, due to limited space in the PITZ original beamline, to compress electron bunches with a beam momentum of 15–20 MeV/c and a charge up to 2 nC. The space charge effect and coherent synchrotron radiation are expected to drastically affect the bunch compressor performance for these parameters, thereby challenging the beam transport throughout the bunch compressor. A staged commissioning strategy was developed in order to achieve optimum bunch compressor operation. The first commissioning procedure establishes electron beam transport throughout the reference path and provides minimum beam momentum dispersion after the bunch compressor. This procedure yielded correlations between dipole magnet currents. As a result, the first bunch compression experiments were performed. Full article

In the majority of experiments targeting nonlinear optical phenomena, the application of high-intensity pulses drives electrons in graphene into a strongly non-equilibrium state. Under these conditions, conventional perturbation theory falls short in explaining graphene’s intricate optical response because of significant deviations in electron distribution over energy states from the equilibrium Fermi-Dirac one. In this work, we present a two-step relaxation model capable of predicting the transient dynamics of graphene’s carriers out of equilibrium, from the generation of spectrally narrow populations of non-thermalized electrons and holes to the establishment of a hot-electron gas and its subsequent cooling toward equilibrium with the crystal lattice. By comparing our model calculations to experimental results, we demonstrate its reliability and relevance to pump–probe experiments, providing insights into the pivotal role of hot electrons in comprehending ultrafast dynamics in graphene. Full article

Rydberg atoms possess highly excited valence electrons that are far away from atomic cations. Compared with ground states, Rydberg states are excited states with a high principal quantum number n that exhibit large electric dipole moments and have a variety of applications in quantum information processing. In this communication, we report the measurement of the ${}^6$Li Rydberg excitation spectrum by ladder-type electromagnetically induced transparency (EIT) in a vapor cell. The 2$p\to ns/nd$ EIT spectra were recorded by sweeping the frequency of an ultraviolet Rydberg pumping laser while keeping the probing laser resonant to the $2s\to 2p$ transition. All lasers were locked on an ultrastable optical Fabry-Pérot cavity and measured by an optical frequency comb. Our results provide valuable information to precisely determine quantum defects and enable novel experiments with Rydberg-dressed ultracold Fermi gases. Full article