Characteristics of broadband OPCPA based on DKDP crystals with different deuterations for the SEL-100 PW laser system.

We present the performances of a broadband optical parametric chirped pulse amplification (OPCPA) using partially deuterated potassium dihydrogen phosphate (DKDP) crystals with deuteration levels of 70% and 98%. When pumped by a Nd:glass double frequency laser, the OPCPA system using the 98% deuterated DKDP crystal achieves a broad bandwidth of 189 nm (full width at 1/e2 maximum) from 836 nm to 1025 nm. For the DKDP crystal with length of 43 mm, the pump-to-signal conversion efficiency reaches 28.4% and the compressed pulse duration is 13.7 fs. For a 70% deuterated DKDP crystal with a length of 30 mm, the amplified spectrum ranges from 846-1021 nm, the compressed pulse duration is 15.7 fs, and the conversion efficiency is 25.5%. These results demonstrate the potential of DKDP crystals with higher deuteration as promising nonlinear crystals for use as final amplifiers in 100 Petawatt (PW) laser systems, supporting compression pulse duration shorter than 15 fs.

Spatio-temporal characterization of tightly focused femtosecond laser fields formed by paraboloidal mirrors with different F-numbers.

The focusing spatiotemporal property of a femtosecond laser pulse is presented under tight focusing conditions by using the frequency-resolved incident electric field and vector diffraction formulas with the wavefront correction term. In the ideal case, the focused laser intensity reaches its maximum at the F-number of ∼0.35 due to the strong diffraction effect under extremely tight focusing conditions. In spatio-temporal coupling distortion cases, their spatiotemporal Strehl ratios show a trend of improvement as the F-number decreases and this phenomenon is mainly concentrated along the y-direction. Based on the numerical calculation method used in this work, the precise information of tightly focused ultra-intense femtosecond laser fields can be obtained, which is crucial for assessing a focused intensity and describing the motion of charged particles under an extremely strong electric field. Moreover, the evolution law of focal fields with spatiotemporal distortions found in this paper can offer some theoretical guidance for realizing ultrahigh laser intensity in the near future.

Treatment with a flow diverter-assisted coil embolization for ruptured blood blister-like aneurysms of the internal carotid artery: a technical note and analysis of single-center experience with pooled data.

Treatment of blood blister-like aneurysms (BBAs) of the supraclinoid internal carotid artery (ICA) with flow diverters (FDs) has become widespread in recent years. However, ruptured blood blister-like aneurysm (BBA) of ICA treatment with flow diverter-assisted coil embolization (FDAC) remains controversial. Moreover, limited direct comparative studies have been conducted between the two treatment modalities, FDs and FDAC, for BBAs. The purpose of this study was to document our experience and evaluate the effectiveness and safety of FDAC. We conducted a retrospective analysis of clinical and radiological information from ten patients who experienced ruptured BBAs of the supraclinoid ICA at our center from January 2021 to February 2023. The technical details of FDAC for ruptured BBAs were described, and the technical steps were named "pipeline embolization device (PED)-Individualized shaping(microcatheter)-Semi deploying-Rivet(coils)-Massage(microwire)" as the PEISSERM technique. Clinical outcomes were assessed using the modified Rankin Scale (mRS), whereas radiological results were determined through angiography. A pooled analysis was implemented, incorporating data from literature sources that reported perioperative and long-term clinical and angiographic outcomes of ruptured BBAs treated with FD and FDAC strategies, along with our data. Data in our analysis pool were categorized into FD and FDAC strategy groups to explore the preferred treatment modalities for BBAs. The PEISSERM technique was utilized to treat ten patients, seven males, and three females, with an average age of 41.7 years. A single PED was deployed in conjunction with coils in all ten patients. All PEDs were documented to have good wall apposition. The immediate postoperative angiograms demonstrated Raymond grade I in ten aneurysms. Angiographic follow-up of nine patients at 4-25 months showed total occlusion of the aneurysms. At the most recent follow-up, the mRS scores of nine patients hinted at a good prognosis. Pooled analysis of 233 ICA-BBA cases of FD revealed a technical success rate of 91% [95% confidence interval (CI), 0.88 to 0.95], a rate of complete occlusion of 79% (95% CI, 0.73 to 0.84), a recurrence rate of 2% (95% CI, 0.00 to 0.04), a rebleed rate of 2% (95% CI, 0.00 to 0.04), and the perioperative stroke rate was 8% (95% CI, 0.04 to 0.11). The perioperative mortality was 4% (95% CI, 0.01 to 0.07). The long-term good clinical outcome rate was 85% (95% CI, 0.80 to 0.90). The mortality rate was 6% (95% CI, 0.03 to 0.09). Results from the subgroup analysis illustrated that the FDAC strategy for BBAs had a significantly higher immediate postoperative complete occlusion rate (P < 0.001), total occlusion rate (P = 0.016), and a good outcome rate (P = 0.041) compared with the FD strategy. The FDAC strategy can yield a higher rate of good outcomes than the FD strategy. The PEISSERM technique employed by the FDAC is a reliable and effective treatment approach as it can minimize the hemodynamic burden of BBA's fragile dome, thereby achieving an excellent occlusion rate. The PEISSERM technique in the FDAC strategy contributes to understanding the BBA's treatment and offers a potentially optimal treatment for BBA.

Has Rural E-Commerce Increased Potato Farmers' Income? Evidence from the Potato Home of China.

Rural e-commerce has achieved an effective interface between rural specialty industries and large markets. This paper explores the impact of rural e-commerce on the income levels of potato farmers based on field survey data. In addition, the extent of the impact of rural e-commerce on the income levels of potato farmers in the participating and non-participating groups was further explored under the counterfactual assumption. The main findings are as follows. (1) Rural e-commerce can increase the income of potato farmers. Participation in rural e-commerce can increase farmers' income in both the participating and non-participating groups. If the participating group had not previously sold potatoes through rural e-commerce, their per capita household income would have been reduced by 27.22%. Similarly, if the non-participating group had sold potatoes through the rural e-commerce platform, their per capita household income would have increased by 36.35%. (2) Under the counterfactual assumption, the impact of rural e-commerce on the incomes of farmers who have not yet sold potatoes through e-commerce platforms is more profound. The marginal income increasing effect of rural e-commerce is currently at an incremental stage, and selling potatoes through an e-commerce platform can lead to higher returns for farmers. (3) Gender, farm household differentiation, self-employment experience, arable land area, position in village and whether participating in agricultural associations or cooperatives are important factors that simultaneously influence farmers' e-commerce participation decisions and income levels. Education and health level can influence farmers' e-commerce participation decisions. Age, farming years, dependency ratio and accessibility to irrigation can influence farmers' income level.

Suppressing scattering-induced nanosecond pre-pulses in Ti:sapphire multi-pass amplifiers.

In this Letter, we experimentally investigate a new kind of nanosecond pre-pulse, which originates from the bidirectional scattering of crystals in traditional Ti:sapphire multi-pass amplifiers. The experimental results demonstrate that the intensity of scattering-induced pre-pulses is very sensitive to the scattering angle, and the delay time between the pre-pulse and the main pulse is an integer multiple of the light path in each pass of the amplifier. An optimized multi-pass amplifier configuration is proposed, for what is believed to be the first time, to suppress the scattering-induced pre-pulses. The contrast ratio between pre-pulses and the main pulse is enhanced by more than two orders of magnitude, reaching a level of 10-10. This novel multi-pass amplifier configuration is very simple and economical, and provides an effective solution for the temporal contrast enhancement in the nanosecond range.

Numerical analysis of the DKDP-based high-energy optical parametric chirped pulse amplifier for a 100 PW class laser.

An optical parametric chirped pulse amplifier (OPCPA) based on a large-aperture DKDP crystal and pumped by a 10 kJ level Nd:glass laser can serve as the final amplifier for a 100 PW level laser. A comprehensive numerical investigation on such a high-energy OPCPA is presented in this work. The effects on the efficiency-bandwidth product induced by the deuteration level, absorption loss, temperature variation, and optimization of zero-phase-mismatch wavelength (ZPMW) are analyzed in detail. Based on the analysis above, a three-dimensional numerical simulation taking into account the effects of pumping depletion, diffraction, and walk-off shows that, by optimization of ZPMW, broadband (over 210 nm spectral width in FWHM) and high efficiency (${\gt}37\%$) amplification can be realized in the DKDP crystal even with a moderate deuteration level of 70%, which can relax the requirement of a high deuteration level in a large-aperture DKDP crystal. The numerical analysis can provide meaningful guidance for the design and construction of 100 PW class laser systems.

RIP1/RIP3/MLKL mediates dopaminergic neuron necroptosis in a mouse model of Parkinson disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder and is characterized by severe neuronal loss. Necroptosis, or programmed cell necrosis, is mediated by the receptor interacting protein kinase-1 and -3/mixed lineage kinase domain-like protein (RIP1/RIP3/MLKL) pathway, and is involved in several neurodegenerative diseases. Here we aimed to explore the involvement of necroptosis in 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine hydrochloride (MPTP)-induced PD and determine the potential mechanisms. We found that the protein levels of RIP1, RIP3, and MLKL increased significantly in a MPTP-induced mouse PD model. High expression of RIP1/RIP3/MLKL was associated with severe loss of dopaminergic neurons. Pretreatment with necrostatin-1 or the knockout of the RIP3/MLKL gene to block necroptosis pathway dramatically ameliorated PD by increasing dopamine levels and rescuing the loss of dopaminergic neurons, independent of the apoptotic pathway. Moreover, upregulation of inflammatory cytokines in MPTP-treated mice was partially inhibited by deletion of RIP3 or MLKL gene, indicating that a positive feedback loop exists between these genes and inflammatory cytokines. Our data indicate that RIP1/RIP3/MLKL-mediated necroptosis is involved in the pathogenesis of MPTP-induced PD. Downregulating the expression of RIP1, RIP3, or MLKL can significantly attenuate MPTP-induced PD. Future therapy targeting necroptosis may be a promising new option.

Serum Ngb (Neuroglobin) Is Associated With Brain Metabolism and Functional Outcome of Aneurysmal Subarachnoid Hemorrhage.

Background and Purpose- Hypoxic-ischemic brain damage is a well-recognized physiopathologic mechanism after aneurysmal subarachnoid hemorrhage (aSAH). The Ngb (neuroglobin) is a hemoprotein predominantly expressed in the brain with a high affinity for oxygen. Relationship between serum Ngb level and brain metabolism in aSAH patients has not been investigated previously. Methods- Thirty-six consecutive severe aSAH patients (Glasgow Coma Scale score ≤8 on admission) with multimodal neuromonitoring and 36 matched healthy subjects were included. Serum Ngb level was analyzed in combination with other time-matched cerebral microdialysis parameters, brain tissue oxygen tension, and 12-month neurological outcomes. Results- Serum Ngb level was correlated positively with cerebral microdialysis parameters and brain tissue oxygen tension ( P<0.001). Poor functional outcome (modified Rankin Scale score >3) 12 months after aSAH was associated with higher Ngb level but independent of age, sex, and disease severity ( P<0.001). A similar association was found between high Ngb level and neuropsychological test results indicative of impairments in cognition, visual conceptualization, and frontal executive functions ( P<0.001). Conclusions- Ngb may be a potential biomarker for reflecting brain tissue oxygen tension, brain metabolism, and functional outcome in severe aSAH patients and merits further study in the context of aSAH.

Improvement of the focusing ability by double deformable mirrors for 10-PW-level Ti: sapphire chirped pulse amplification laser system.

Double deformable mirrors (DMs) with different actuator densities are cascaded to optimize the wavefront aberrations to improve the focus intensity of the Shanghai super-intense ultrafast laser facility (SULF), which plans to generate 10 PW laser pulse. The beam aberrations near the focal spot are corrected from 0.556 um to 0.112 um in RMS by a 300-mm DM with a large stroke installed after the compressor. After then, it is further optimized to 0.041 um using a 130-mm DM with a high spatial resolution working after the main amplifier. The corrected beam is focused to 2.75 × 2.87 um2 at the full width at half maximum (FWHM) with an f/2.5 off-axis parabolic mirror (OAP), which contains approximately 27.69% energy. A peak intensity of 2 × 1022 W/cm2 is achieved at the output of 5.4 PW, and it could exceed 1023 W/cm2 in the SULF 10 PW laser facility using an f/1.8 OAP.

339 J high-energy Ti:sapphire chirped-pulse amplifier for 10 PW laser facility.

We report on the laser pulse output of 339 J centered at 800 nm from a chirped-pulse amplification (CPA) Ti:sapphire laser system at the Shanghai Superintense Ultrafast Laser Facility. The experimental results demonstrated that the parasitic lasing as well as the transverse amplified spontaneous emission of the homemade 235-mm-diameter Ti:sapphire final amplifier were suppressed successfully via the temporal dual-pulse pumped scheme and the index-matching liquid cladding technique. The maximum pump-to-signal conversion efficiency of 32.1% was measured for the final amplifier. With a compressor transmission efficiency of 64% and a compressed pulse duration of 21 fs obtained for the sample light at a lower energy level, this laser system could potentially generate a compressed laser pulse with a peak power of 10.3 PW. The experimental results represent significant progress with respect to the CPA laser.

Optimizing the performance of non-collinear optical parametric chirped pulse amplification via multi-pass structure based on two geometry configurations.

We propose a method for multi-pass non-collinear optical parametric chirped pulse amplification (MNOPCPA) based on two geometries, tangent phase-matching (TPM) and Poynting vector walk-off compensation (PVWC), which optimize the performance of optical parametric chirped pulse amplification (OPCPA). A feasible design scheme is also presented for use in implementing this approach. Employing this design, we construct and perform a numerical simulation, showing that back-conversion from the signal and idler to the pump can be inhibited, and that the conversion efficiency can be boosted dramatically, approaching the theoretical limit of ~64%, when amplification is nearly saturated at full bandwidth. In the MNOPCPA scheme, the output signal has a wider spectrum and a corresponding shorter Fourier-limited pulse duration with the pump being continuously depleted. A barycenter shift of the signal spot results from a spatial walk-off effect due to the pump, which can be offset and corrected well. To the best of our knowledge, this is the first demonstration of a multi-pass non-collinear OPCPA method employed the scheme of regenerative amplification.

High-order dispersion control of 10-petawatt Ti:sapphire laser facility.

A grism pair is utilized to control the high-order dispersion of the Shanghai Superintense Ultrafast Lasers Facility, which is a large-scale project aimed at delivering 10-PW laser pulses. We briefly present the characteristics of the laser system and calculate the cumulative B-integral, which determines the nonlinear phase shift influence on material dispersion. Three parameters are selected, grism separation, angle of incidence and slant distance of grating compressor, to determine their optimal values through an iterative searching procedure. Both the numerical and experimental results confirm that the spectral phase distortion is controlled, and the recompressed pulse with a duration of 24 fs is obtained in the single-shot mode. The distributions and stabilities of the pulse duration at different positions of the recompressed beam are also investigated. This approach offers a new feasible solution for the high-order dispersion compensation of femtosecond petawatt laser systems.

200 J high efficiency Ti:sapphire chirped pulse amplifier pumped by temporal dual-pulse.

We report on an experimental and theoretical study of a large-aperture Ti:Sapphire (Ti:S) amplifier pumped with a novel temporal dual-pulse scheme to suppress the parasitic lasing (PL) and transverse amplified spontaneous emission (TASE) for high-energy chirped-pulse amplification (CPA). The pump energy distribution was optimized and the time delay between each pump pulse was controlled precisely. Both the numerical and experimental results confirm that the temporal dual-pulse pump technique can effectively suppress PL and TASE. The maximum output energy of 202.8 J was obtained from the final 150-mm-diameter Ti:S booster amplifier with a pump energy of 320.0 J, corresponding to a conversion efficiency of 49.3%. The compressed pulse duration of 24.0 fs was measured with a throughput efficiency of 64%, leading to a peak power of 5.4 PW. This novel temporal dual-pulse pump technique has potential applications in a 10 PW CPA laser system.

High-energy large-aperture Ti:sapphire amplifier for 5 PW laser pulses.

We report on the generation of 192.3 J centered at 800 nm wavelength from a chirped-pulse amplification (CPA) Ti:sapphire laser system. The experimental results demonstrate that parasitic lasing can be suppressed successfully in the final amplifier based on a Ti:sapphire crystal of 150 mm in diameter. An over 50% pump-to-signal conversion efficiency was measured for the final amplifier by optimizing the time delay of two pump pulses and enhancing the injected seed energy. With 72% compressor throughput efficiency and 27 fs long compressed pulse duration obtained at a lower energy level, this laser could potentially support a compressed laser pulse of 5.13 PW peak power. The experimental results represent notable progress regarding the CPA laser.

Optimization for high-energy and high-efficiency broadband optical parametric chirped-pulse amplification in LBO near 800 nm.

In this Letter, we present a study of high-energy and high-conversion-efficiency broadband optical parametric chirped-pulse amplification (OPCPA) system with a 100 mm×100 mm×17 mm LBO crystal near 800 nm. The results showed that the back-conversion was sensitively affected by the pump intensity and the injected signal intensity. It occurred when the injected signal was above 0.82 J with a pump energy of 170 J, and this effect also reshaped the amplified spectrum. After optimization, an amplified energy of 45.3 J was achieved with a conversion efficiency of 26.3% by the OPCPA. The peak power of the hybrid CPA-OPCPA laser system reached 1.02 PW with a compressed duration of 32 fs, which is the first reported OPCPA peak power higher than 1 PW, to the best of our knowledge.

Suppression of transverse parasitic lasing and amplified spontaneous emission in Ti:sapphire amplifier by polarization-selection pump.

Based on the polarized-dependent absorption characteristic of Ti:S crystals, we propose a method to reduce the absorption coefficient of Ti:S by using a σ-polarized pump. For Ti:S crystals, the absorption cross section of σ-polarized pump light is approximately half that of π-polarized pump light, which reduces the excited state density near the surface of the amplifier crystal, resulting in reduced transverse parasitic lasing and amplified spontaneous emission. The experimental results based on a diameter of 80 mm Ti:S confirmed the proposed method with different index-matched cladding materials [ethanol and bromonaphthalene (BN)]. In the case of an ethanol cladding, the maximum amplified output energies for π- and σ-polarized pumping are 20.8 J and 26.8 J, respectively-corresponding to 28.8% energy improvement achieved by the σ-polarized pump. In the case of a BN cladding, the maximum amplified output energies achieved by π- and σ-polarized pumping are 40 J and 44 J, respectively; this result corresponds to about 10% energy improvement achieved by the σ-polarized pump. This method can be used in larger size Ti:S amplifiers.

A movable microelectrode array for chronic basal ganglia single-unit electrocorticogram co-recording in freely behaving rats.

The basal ganglia-cortical circuits are important for information process to brain function. However, chronic recording of single-unit activities in the basal ganglia nucleus has not yet been well established. We present a movable bundled microwire array for chronic subthalamic nucleus (STN) single-unit electrocorticogram co-recording. The electrode assembly contains a screw-advanced microdrive and a microwire array. The array consists of a steel guide tube, five recording wires and one referenced wire which form the shape of a guiding hand, and one screw electrode for cortico-recording. The electrode can acquire stable cortex oscillation-driven STN firing units in rats under different behaving conditions for 8 weeks. We achieved satisfying signal-to-noise ratio, portions of cells retaining viability, and spike waveform similarities across the recording sections. Using this method, we investigated neural correlations of the basal ganglia-cortical circuits in different behaving conditions. This method will become a powerful tool for multi-region recording to study normal statements or movement disorders.

Enhanced Treatment Options for Dural Arteriovenous Fistulas at the Craniocervical Junction: Endovascular Embolization Versus Microsurgery? A Single-Center 23-Year Experience.

OBJECTIVE: The occurrence of dural arteriovenous fistulas (DAVFs) at the craniocervical junction (CCJ) is an uncommon vascular malformation. The diagnosis and treatment of CCJ DAVFs present a formidable challenge. This study aims to investigate the effect of endovascular embolization and microsurgery on improving patient prognosis. METHODS: This retrospective study included patients diagnosed with CCJ DAVFs who received treatment at the First Affiliated Hospital of Fujian Medical University between January 2000 and January 2023. The clinical records, imaging data, and treatment methods were obtained from the hospital's medical record system. The patients were classified into microsurgery and embolization groups based on the surgical technique employed for treatment. The primary outcome measures were surgical-associated neurological dysfunction (SAND) and long-term neurological outcomes. The Cox proportional hazard regression was utilized to determine hazard ratios and 95% confidence intervals (CI) to assess the relationship between treatment methods and prognosis. Kaplan-Meier survival analysis was employed to evaluate the incidence of SAND in both cohorts. RESULTS: This study recruited 46 patients with an average age of 53.72 ± 13.83 years. In the microsurgery group, there were 12 cases (26.1%) observed. While in the embolization group, there were 34 cases (73.9%). Of these patients, 16 (34.8%) experienced SAND after treatment. In the microsurgery group, there were 8 cases (75.0%), while in the embolization group, only 8 cases (23.5%) were reported. Specifically, the embolization group exhibited a significantly lower risk of SAND [adjusted hazard ratio = 0.259, 95% CI = 0.096-0.700; P = 0.008)] compared to the microsurgery group. Additionally, the combined Borden grade 2-3 was found to be significantly associated with SAND (adjusted hazard ratio = 3.150, 95% CI = 1.132-8.766; P = 0.028). The results of the Kaplan-Meier survival analysis indicated a statistically significant difference in the occurrence of favorable functional outcomes between the 2 groups (log-rank P = 0.0081). CONCLUSIONS: CCJ DAVFs are uncommon disorders characterized by a diverse range of clinical manifestations. The functional prognosis of endovascular treatment may be superior to microsurgery.

High-contrast 2.0 Petawatt Ti:sapphire laser system.

We report on a 2.0 PW femtosecond laser system at 800 nm based on the scheme of chirped pulse amplification using Ti:sapphire crystals, which is the highest peak power ever achieved from a femtosecond laser system. Combining the index-matching cladding technique and the precise control of the time delay between the input seed pulse and pump pulses, the parasitic lasing in the final booster amplifier is effectively suppressed at the pump energy of 140 J at 527 nm. The maximum output energy from the final amplifier is 72.6 J, corresponding to a conversion efficiency of 47.2% from the pump energy to the output laser energy. The measured spectral width of the amplified output pulse from the final amplifier is 60.8 nm for the full width at half-maximum (FWHM) by controlling the spectral evolution in the amplifier chain, and the recompressed pulse duration is 26.0 fs. The technology of cross-polarized wave (XPW) is applied in a broadband front-end, and the pulse contrast is improved to ~1.5 × 10¹¹ (-100 ps before the main pulse) which is measured at 83 TW power level with a repetition rate of 5 HZ.