Distinguishing the nonlinear propagation regimes of vortex femtosecond pulses in fused silica by evaluating the broadened spectrum.

The nonlinear propagation dynamics of vortex femtosecond laser pulses in optical media is a topic with significant importance in various fields, such as nonlinear optics, micromachining, light bullet generation, vortex air lasing, air waveguide and supercontinuum generation. However, how to distinguish the various regimes of nonlinear propagation of vortex femtosecond pulses remains challenging. This study presents a simple method for distinguishing the regimes of nonlinear propagation of femtosecond pulses in fused silica by evaluating the broadening of the laser spectrum as the input pulse power gradually increases. The linear, self-focusing and mature filamentation regimes for Gaussian and vortex femtosecond pulses in fused silica are distinguished. The critical powers for self-focusing and mature filamentation of both types of laser pulses are obtained. Our work provides a rapid and convenient method for distinguishing different regimes of nonlinear propagation and determining the critical powers for self-focusing and mature filamentation of Gaussian and structured laser pulses in optical media.

Development and validation of a risk-prediction model for immune-related adverse events in patients with non-small-cell lung cancer receiving PD-1/PD-L1 inhibitors.

Lung cancer remains the leading cause of cancer deaths worldwide and is the most common cancer in males. Immune-checkpoint inhibitors (ICIs) that target programmed cell death protein-1 (PD-1) or programmed cell death-ligand 1 (PD-L1) have achieved impressive efficacy in the treatment of non-small-cell lung cancer (NSCLC) (Pardoll, 2012; Champiat et al., 2016; Gao et al., 2022). Although ICIs are usually well tolerated, they are often accompanied by immune-related adverse events (irAEs) (Doroshow et al., 2019). Non-specific activation of the immune system produces off-target immune and inflammatory responses that can affect virtually any organ or system (O'Kane et al., 2017; Puzanov et al., 2017). Compared with adverse events caused by chemotherapy, irAEs are often characterized by delayed onset and prolonged duration and can occur in any organ at any stage of treatment, including after cessation of treatment (Puzanov et al., 2017; von Itzstein et al., 2020). They range from rash, pneumonitis, hypothyroidism, enterocolitis, and autoimmune hepatitis to cardiovascular, hematological, renal, neurological, and ophthalmic irAEs (Nishino et al., 2016; Kumar et al., 2017; Song et al., 2020). Hence, we conducted a retrospective study to identify validated factors that could predict the magnitude of the risk of irAEs in patients receiving PD-1/PD-L1 inhibitors; our approach was to analyze the correlation between the clinical characteristics of patients at the start of treatment and relevant indicators such as hematological indices and the risk of developing irAEs. Then, we developed an economical, practical, rapid, and simple model to assess the risk of irAEs in patients receiving ICI treatment, as early as possible.

Experimentally determined critical power for self-focusing of femtosecond vortex beams in air by a fluorescence measurement.

The filamentation of the femtosecond vortex beam has attracted much attention because of the unique filamentation characteristics, such as annular distribution and helical propagation, and related applications. The critical power for self-focusing of the femtosecond vortex beams is a key parameter in the filamentation process and applications. But until now, there is no quantitative determination of the critical power. In this work, we experimentally determine the self-focusing critical power of femtosecond vortex beams in air by measuring fluorescence using a photomultiplier tube. The relation between the self-focusing critical power and the topological charge is further obtained. Our work provides a simple method to determine the self-focusing critical power not only for vortex beams but also for Airy, Bessel, vector, and other structured laser beams.

Influence of a pinhole diameter on the experimental determination of critical power for femtosecond filamentation in air.

Filamentation of intense femtosecond laser pulses in optical media has attracted great attention due to its various unique characteristics and potential applications. It is an important task to determine the critical power for the filamentation especially in many applications, which can be obtained by evaluating the transmitted pulse energy through a pinhole located in the filamentation region as a function of input laser energy. The pinhole diameter is very crucial to the measurement. However, there is no report on the experimental determination of critical power for filamentation in air by using the pinhole method and the influence of the pinhole diameter on the determination. In this paper, we numerically and experimentally investigate the influence of pinhole diameter on the determination of the filamentation critical power. The obtained critical power tends to a reasonable value as the decrease of the pinhole diameter, because the transmitted energy through the pinhole with a smaller diameter is more sensitive to the change of energy distribution in the beam cross section during the beginning process of filamentation. Under our experimental condition, the pinhole diameter as small as ∼50 µm is applicable to be used to determine the critical power for filamentation of femtosecond laser pulses in air.

Simultaneous spatial and temporal focusing optical vortex pulses for micromachining through optically transparent materials.

We introduce the optical vortex beam into simultaneous spatial and temporal focusing (SSTF) technique, and theoretically and experimentally demonstrate the local control of peak intensity distribution at the focus of a simultaneous spatiotemporally focused optical vortex (SSTF OV) beam. To avoid nonlinear self-focusing in the conventional focusing scheme, a spatiotemporally focused femtosecond laser vortex beam was employed to achieve doughnut-shaped ablation and high aspect ratio (∼28) microchannels on the back surface of 3 mm thick soda-lime glass and fused silica substrates.

Intense vector supercontinuum radiation from femtosecond filamentation.

Intense vector supercontinuum (SC) radiation with spatial polarization is obtained by using 800nm femtosecond vector laser beams in the air. The SC generated by azimuthally, radially, cylindrically polarized beams, and higher-order vector beams are investigated, respectively. The results show that the SC generated by vector beams is greatly enhanced compared to that by a Gaussian beam. The energy density of SC radiation reaches the order of 1µJ/nm in a bandwidth of 258 nm from 559 nm to 817 nm and 0.1 µJ/nm from 500 nm to 559 nm. Furthermore, by checking the polarization distribution of SC in different wavelengths from visible to near-infrared bands, we find that the SC maintains nearly the same polarization distribution as pump pulses. This work provides an effective and convenient way to generate powerful SC vector beams which may facilitate potential applications including optical communication, micro/nano-fabrication, and super-resolution microscopy.

Predictive nomogram of cage nonunion after anterior cervical discectomy and fusion: A retrospective study in a spine surgery center.

The cage nonunion may cause serious consequences, including recurrent pain, radiculopathy, and kyphotic deformity. The risk factors for nonunion following anterior cervical discectomy and fusion (ACDF) are controversial. The aim of the study is to investigate the risk factors for nonunion in cervical spondylotic cases after ACDF. We enrolled 58 and 692 cases in the nonunion and union group respectively and followed up the cases at least 6 months. Patient demographic information, surgical details, cervical sagittal parameters, and the serum vitamin D level were collected. A logistic regression was performed to determine the independent predictors for nonunion, which were used for establishing a nomogram. In order to estimate the reliability and the net benefit of nomogram, we applied a receiver operating characteristic curve analysis, calibration curves and plotted decision curves. Using the multivariate logistic regression, we found that age (odds ratio [OR] = 1.16, P < .001), smoking (OR = 3.41, P = .001), angle of C2 to C7 (OR = 1.53, P < .001), number of operated levels (2 levels, OR = 0.42, P = .04; 3 levels, OR = 1.32, P = .54), and serum vitamin D (OR = 0.81, P < .001) were all significant predictors of nonunion (Table 3). The area under the curve of the model training cohort and validation cohort was 0.89 and 0.87, respectively. The calibration curves showed that the predicted outcome fitted well to the observed outcome in the training cohort (P = .102,) and validation cohort (P = .125). The decision curves showed the nomogram had more benefits than the All or None scheme if the threshold probability is >10% and <100% in training cohort and validation cohort. We found that age, smoking, angle of C2 to C7, number of operated levels, and serum vitamin D were all significant predictors of nonunion.

Outcomes of seromuscular bladder augmentation compared with standard bladder augmentation in the treatment of children with neurogenic bladder.

BACKGROUND: Intestinal seromuscular bladder augmentation (SMBA) surgery has produced no mucosal-related complications, but its outcomes need to be studied. AIM: To evaluate the safety and effectiveness of SMBA in the treatment of children with neurogenic bladder. METHODS: A retrospective analysis of the clinical data of children with SMBA was performed from March 2008 to February 2018, and the data were compared with those of children receiving standard cystoplasty (SC). RESULTS: In a cohort of 67 children who underwent bladder augmentation, the 46 children in the SC group had an average age of 10.6 years and a follow-up time of 36 mo, and the 21 children in the SMBA group had an average age of 7.6 years and a follow-up time of 29.7 mo. The preoperative and postoperative bladder volumes in the SMBA group were 151.7 mL and 200.4 mL, respectively, and those in the SC group were 173.9 mL and 387.0 mL, respectively. No significant difference in preoperative urinary dynamic parameters was found between the two groups, but the difference after operation was statistically significant. The main complications after SMBA were residual ureteral reflux and failed bladder augmentation, with incidences of 33.3% and 28.6%, respectively. In all 6 patients with failed augmentation in the SMBA group, ileum seromuscular patches were used for augmentation, and SC was chosen for reaugmentation. During reoperation, patch contracture and fibrosis were observed. CONCLUSION: The improvement of urinary dynamic parameters in the SMBA group was significantly lower than that in the SC group. Children with SMBA had a higher probability of patch contracture and reaugmentation, which might be related to impaired blood supply and urine stimulation, and the sigmoid colon patch should be the priority.

A Novel Mutation c.3392G>T of COL2A1 Causes Spondyloepiphyseal Dysplasia Congenital by Affecting Pre-mRNA Splicing.

Spondyloepiphyseal dysplasia congenital (SEDC) is a rare chondrodysplasia caused by dominant pathogenic variants in COL2A1. Here, we detected a novel variant c.3392G > T (NM_001844.4) of COL2A1 in a Chinese family with SEDC by targeted next-generation sequencing. To confirm the pathogenicity of the variant, we generated an appropriate minigene construct based on HeLa and HEK293T cell lines. Splicing assay indicated that the mutated minigene led to aberrant splicing of COL2A1 pre-mRNA and produced an alternatively spliced transcript with a skipping of partial exon 48, which generated a predicted in-frame deletion of 15 amino acids (p. Gly1131_Pro1145del) in the COL2A1 protein. Due to the pathogenicity of the variation, we performed prenatal diagnosis on the proband's wife, which indicated that the fetus carried the same mutation.