Comparative study of optical fiber immunosensors based on traditional antibody or nanobody for detecting HER2.

In this study, we present a novel biomarker detection platform employing a modified S-tapered fiber coated with gold nanoparticle/graphene oxide (GNP/GO) for quantifying human epidermal growth factor receptor-2 (HER2) concentrations, using antibodies as sensing elements. The fabrication of this device involves implementing an in-situ layer-by-layer technique coupled with a chemical adsorption step to achieve the self-assembly of GNP, GO, and antibodies on the STF surface. The detection mechanism relies on monitoring the refractive index changes induced by the adsorption of HER2 onto the immobilized antibodies. For comparative analysis, both monoclonal antibody (mAb) and the novel nanobody (Nb) were employed in constructing the STF immunosensor, referred to as the mAb immunosensor and Nb immunosensor, respectively. Spectral analysis results highlight that the Nb immunosensor exhibits twice the sensitivity of the mAb immunosensor. This enhanced sensitivity is attributed to the small size, high antigen affinity, strong specificity, and structural stability of Nb. The Nb immunosensor demonstrated an impressive detection limit of 0.001 nM for HER2, surpassing the detection limit of the mAb immunosensor. These findings underscore the potential of the proposed Nb immunosensor as a promising and sensitive tool for HER2 detection, contributing to the diagnosis and prognosis of breast cancer. Furthermore, the simplicity of production and excellent optical performance position the Nb immunosensor as a prospective real-time biosensor with minimal cytotoxicity.

Concerning for the solvent-polarity-dependent conformational equilibrium and ESIPT mechanism in Pz3HC system: A novel insight.

In this report, we propose a new insight into the interaction between the solvent-polarity-dependent conformational equilibrium and excited state intramolecular proton transfer (ESIPT) behavior of Pz3HC system in four different polar solvents (polarity order: ACN > THF > TOL > CYC). Using quantum chemistry method, we first announce a coexistence mechanism between Pz3HC-1 and Pz3HC-3 in the ground state in four solvents based on the Boltzmann distribution. In particular, Pz3HC-1 is the principal configuration in non-polar solvent, but Pz3HC-3 is the principal configuration in polar solvent. In addition, the simulated fluorescence spectra interprets the negative solvatochromism effect of Pz3HC-1 and Pz3HC-3 in four solvents. The evidence from intramolecular hydrogen bonding (IHB) parameters and electronic perspective collectively confirms the light-induced IHB enhancement and intramolecular charge transfer (ICT) properties in Pz3HC-1 and Pz3HC-3, which raises the likelihood of the ESIPT process. Combining the calculation of potential energy curve (PEC) and intrinsic reaction coordinate (IRC), we demonstrate that the ESIPT ease of Pz3HC-1 in different polar solvents obeys the order of CYC > TOL > THF > ACN, while the order of ESIPT ease in Pz3HC-3 is opposite. Notably, the ESIPT process of Pz3HC-3 in CYC solvent is accompanied by the twisted intramolecular charge transfer (TICT) process. In addition, we also reveal that the enol* and keto* fluorescence peaks of Pz3HC-3 in CYC solvent are quenched by ISC and TICT process, respectively. Our work not only provides a satisfactory explanation of the novel dynamics mechanism for Pz3HC system, but also brings light to the design and application of new sensing molecules in the future.

Development and validation of a nomogram for predicting 28-day mortality in patients with ischemic stroke.

BACKGROUND/AIM: We aimed to construct a validated nomogram model for predicting short-term (28-day) ischemic stroke mortality among critically ill populations. MATERIALS AND METHODS: We collected raw data from the Medical Information Mart for Intensive Care IV database, a comprehensive repository renowned for its depth and breadth in critical care information. Subsequently, a rigorous analytical framework was employed, incorporating a 10-fold cross-validation procedure to ensure robustness and reliability. Leveraging advanced statistical methodologies, specifically the least absolute shrinkage and selection operator regression, variables pertinent to 28-day mortality in ischemic stroke were meticulously screened. Next, binary logistic regression was utilized to establish nomogram, then applied concordance index to evaluate discrimination of the prediction models. Predictive performance of the nomogram was assessed by integrated discrimination improvement (IDI) and net reclassification index (NRI). Additionally, we generated calibration curves to assess calibrating ability. Finally, we evaluated the nomogram's net clinical benefit using decision curve analysis (DCA), in comparison with scoring systems clinically applied under common conditions. RESULTS: A total of 2089 individuals were identified and assigned into training (n = 1443) or validation (n = 646) cohorts. Various identified risk factors, including age, ethnicity, marital status, underlying metastatic solid tumor, Charlson comorbidity index, heart rate, Glasgow coma scale, glucose concentrations, white blood cells, sodium concentrations, potassium concentrations, mechanical ventilation, use of heparin and mannitol, were associated with short-term (28-day) mortality in ischemic stroke individuals. A concordance index of 0.834 was obtained in the training dataset, indicating that our nomogram had good discriminating ability. Results of IDI and NRI in both cohorts proved that our nomogram had positive improvement of predictive performance, compared to other scoring systems. The actual and predicted incidence of mortality showed favorable concordance on calibration curves (P > 0.05). DCA curves revealed that, compared with scoring systems clinically used under common conditions, the constructed nomogram yielded a greater net clinical benefit. CONCLUSIONS: Utilizing a comprehensive array of fourteen readily accessible variables, a prognostic nomogram was meticulously formulated and rigorously validated to provide precise prognostication of short-term mortality within the ischemic stroke cohort.

Composite membrane of graphene oxide and gold nanoparticles functionalized S fiber taper aptasensor for highly sensitive bisphenol A detection.

The S fiber taper (SFT) aptasensor with a composite sensitive membrane of graphene oxide and gold nanoparticles was proposed for the rapid and highly sensitive detection of bisphenol A (BPA). The SFT was obtained using a fusion splicer; subsequently, the composite film was deposited on its surface, and the specific aptamer was covalently bonded to the surface of gold nanoparticles. The detection mechanism relies on monitoring changes in the external refractive index induced by the specific binding of BPA to the aptamer. The developed SFT aptasensor exhibited a remarkable sensitivity of 15.5 nm/nM and a limit of detection as low as 0.01 nM for BPA. These findings highlight the aptasensor's potential for diverse monitoring applications.

Development of a nomogram to predict the incidence of acute kidney injury among ischemic stroke individuals during ICU hospitalization.

Background: Limited clinical prediction models exist to assess the likelihood of acute kidney injury (AKI) occurrence in ischemic stroke individuals. In this retrospective study, our aim was to construct a nomogram that utilizes commonly available clinical features to predict the occurrence of AKI during intensive care unit hospitalization among this patient population. Methods: In this study, the MIMIC-IV database was utilized to investigate potential risk factors associated with the incidence of AKI among ischemic stroke individuals. A predictive nomogram was developed based on these identified risk factors. The discriminative performance of the constructed nomogram was assessed. Calibration analysis was utilized to evaluate the calibration performance of the constructed model, assessing the agreement between predicted probabilities and actual outcomes. Furthermore, decision curve analysis (DCA) was employed to assess the clinical net benefit, taking into account the potential risks and benefits associated with different decision thresholds. Results: A total of 2089 ischemic stroke individuals were included and randomly allocated into developing (n = 1452) and verification cohorts (n = 637). Risk factors for AKI incidence in ischemic stroke individuals, determined through LASSO and logistic regression. The constructed nomogram had good performance in predicting the occurrence of AKI among ischemic stroke patients and provided significant improvement compared to existing scoring systems. DCA demonstrated satisfactory clinical net benefit of the constructed nomogram in both the validation and development cohorts. Conclusions: The developed nomogram exhibits robust predictive performance in forecasting AKI occurrence in ischemic stroke individuals.

Thermal stress analysis of laser cleaning of aluminum alloy oxide film.

In this paper, a theoretical model for laser cleaning of aluminium alloy oxide film is presented from the perspective of thermal stress. Additionally, we developed a two-dimensional axisymmetric finite element model for calculation. Thermal stresses result from thermal expansion. Using thermodynamic equations, numerical calculations enable the determination of a theoretical cleaning threshold by comparing the thermal stresses to the adhesion between the oxide film and the substrate. Through theory and experiments, it is known that the greater the laser fluence, the better is the cleaning effect. The findings indicate that cleaning of the oxide film on aluminum alloys can be achieved under appropriate parameters. The cleaning threshold for laser cleaning of the oxide film is determined to be 3629.47J/c m 2 (continuous laser fluence is 3628.73J/c m 2; nanosecond laser fluence is 0.74J/c m 2). The thermal stress model of laser cleaning is highly useful for selecting the appropriate laser flux in practical applications. Both a simulation and experimental results can provide an explanation for the mechanism of interaction between the laser and the aluminum alloy oxide film, demonstrating that thermal stress is one of the cleaning mechanisms during the laser cleaning process of the oxide film.

Charge disproportionation-induced multiferroics and electric field control of magnetism in a 2D MXene - Mo2NCl2.

Two-dimensional (2D) magnetoelectric multiferroic materials with the coexistence of magnetization and ferroelectric polarization hold potential for application for the development of next-generation nano-memory devices. However, intrinsic 2D multiferroics with a high critical temperature and strong magnetoelectric coupling are still rare to date. Here, we propose a novel mechanism of 2D monolayer multiferroicity. Based on density functional theory (DFT), we predicted that in a Mo2NCl2 monolayer, the non-equilibrium charge disproportionation of Mo ions will induce an out-of-plane electric polarization, making this material a 2D monolayer multiferroic material. More importantly, the magnetic critical temperature is calculated to be ∼168 K, which is larger than those of the recently reported 2D multiferroic and ferromagnetic systems. Our findings also provide a promising platform to control the magnetic properties and electric behavior in 2D multiferroics using an external electric field.

Paying Comprehensive Attention to the Temperature-Dependent Dual-Channel Excited-State Intramolecular Proton Transfer Mechanism of Fluorescence Ratio Probe BZ-DAM.

The mechanism of fluorescence detection of diethyl chlorophosphate (DCP) based on 2-substituted benzothiazole (BZ-DAM) was studied by a theoretical calculation method. It should not be ignored that both the BZ-DAM and the detection product BZ-CHO have two excited-state intramolecular proton transfer (ESIPT) channels. Density functional theory (DFT) and time-dependent DFT (TDDFT) theory were used to study the photophysical mechanism of two compounds in two channels in (acetonitrile) ACN solvent, and the temperature dependence of the two channels was given. Channel 1 is more likely to exist at low temperatures and channel 2 is more likely to exist at high temperatures. By theoretical analysis of the constructed potential energy curve, the hydrogen bond energy and electron-hole analysis, we confirmed that both molecules undergo ESIPT and intramolecular charge transfer (ICT) processes in channel 1 and ESIPT and twisted intramolecular charge transfer (TICT) coupling processes in channel 2. The formation of product BZ-CHO molecules led to a significant fluorescence blue-shift phenomenon and inhibited the ICT process, which confirmed that BZ-DAM could be used as a fluorescence probe for fluorescence detection. We sincerely hope that this work will not only help to clarify the excited-state dynamics behavior of the BZ-DAM probe but also provide a new idea for designing and optimizing a new chemical dosimeter.

Development and verification of a nomogram for predicting short-term mortality in elderly ischemic stroke populations.

Stroke is a major healthcare problem worldwide, particularly in the elderly population. Despite limited research on the development of prediction models for mortality in elderly individuals with ischemic stroke, our study aimed to address this knowledge gap. By leveraging data from the Medical Information Mart for Intensive Care IV database, we collected comprehensive raw data pertaining to elderly patients diagnosed with ischemic stroke. Through meticulous screening of clinical variables associated with 28-day mortality, we successfully established a robust nomogram. To assess the performance and clinical utility of our nomogram, various statistical analyses were conducted, including the concordance index, integrated discrimination improvement (IDI), net reclassification index (NRI), calibration curves and decision curve analysis (DCA). Our study comprised a total of 1259 individuals, who were further divided into training (n = 894) and validation (n = 365) cohorts. By identifying several common clinical features, we developed a nomogram that exhibited a concordance index of 0.809 in the training dataset. Notably, our findings demonstrated positive improvements in predictive performance through the IDI and NRI analyses in both cohorts. Furthermore, calibration curves indicated favorable agreement between the predicted and actual incidence of mortality (P > 0.05). DCA curves highlighted the substantial net clinical benefit of our nomogram compared to existing scoring systems used in routine clinical practice. In conclusion, our study successfully constructed and validated a prognostic nomogram, which enables accurate short-term mortality prediction in elderly individuals with ischemic stroke.

Prediction of long-term mortality in patients with ischemic stroke based on clinical characteristics on the first day of ICU admission: An easy-to-use nomogram.

Background: This study aimed to establish and validate an easy-to-use nomogram for predicting long-term mortality among ischemic stroke patients. Methods: All raw data were obtained from the Medical Information Mart for Intensive Care IV database. Clinical features associated with long-term mortality (1-year mortality) among ischemic stroke patients were identified using least absolute shrinkage and selection operator regression. Then, binary logistic regression was used to construct a nomogram, the discrimination of which was evaluated by the concordance index (C-index), integrated discrimination improvement (IDI), and net reclassification index (NRI). Finally, a calibration curve and decision curve analysis (DCA) were employed to study calibration and net clinical benefit, compared to the Glasgow Coma Scale (GCS) and the commonly used disease severity scoring system. Results: Patients who were identified with ischemic stroke were randomly assigned into developing (n = 1,443) and verification (n = 646) cohorts. The following factors were associated with 1-year mortality among ischemic stroke patients, including age on ICU admission, marital status, underlying dementia, underlying malignant cancer, underlying metastatic solid tumor, heart rate, respiratory rate, oxygen saturation, white blood cells, anion gap, mannitol injection, invasive mechanical ventilation, and GCS. The construction of the nomogram was based on the abovementioned features. The C-index of the nomogram in the developing and verification cohorts was 0.820 and 0.816, respectively. Compared with GCS and the commonly used disease severity scoring system, the IDI and NRI of the constructed nomogram had a statistically positive improvement in predicting long-term mortality in both developing and verification cohorts (all with p < 0.001). The actual mortality was consistent with the predicted mortality in the developing (p = 0.862) and verification (p = 0.568) cohorts. Our nomogram exhibited greater net clinical benefit than GCS and the commonly used disease severity scoring system. Conclusion: This proposed nomogram has good performance in predicting long-term mortality among ischemic stroke patients.

Mechanism of paint removal by nanosecond pulsed laser plasma shock: simulation and experiment.

This paper establishes a new theoretical paint removal model of plasma shock based on Fabbro's model and Newton's second law. A two-dimensional axisymmetric finite element model is established to calculate the theoretical model. By comparing the theoretical and experimental results, it is found that the theoretical model can accurately predict the threshold of laser paint removal. It is indicated that plasma shock is an essential mechanism in laser paint removal. The threshold for laser paint removal is approximately 1.73J/c m 2. The experiments show that, with the increase of the laser fluence, the effect of laser paint removal first increases and then decreases. With the increase of the laser fluence, the paint removal effect is improved due to the increase of the paint removal mechanism. The competition between the plastic fracture and pyrolysis leads to a reduction in paint effectiveness. In summary, this study can provide a theoretical reference for studying the paint removal mechanism of plasma shock.

Asymmetric Janus functionalization induced magnetization and switchable out-of-plane polarization in 2D MXene Mo2CXX'.

Exploring two-dimensional (2D) van der Waals materials with out-of-plane polarization and electromagnetic coupling is essential for the development of next-generation nano-memory devices. A novel class of 2D monolayer materials with predicted spin-polarized semi-conductivity, partially compensated antiferromagnetic (AFM) order, fairly high Curie temperature, and out-of-plane polarization is analyzed in this work for the first time. Based on density functional theory calculations, we systematically studied these properties in asymmetrically functionalized MXenes (Janus Mo2C)-Mo2CXX' (X, X' = F, O, and OH). Using ab initio molecular dynamics (AIMD) and phonon spectrum calculations, the thermal and dynamic stabilities of six functionalized Mo2CXX' were identified. Our DFT+U calculation results also provided a switching path for out-of-plane polarizations, where the reverse of electric polarization is driven by terminal-layer atom flipping. More importantly, strong coupling between magnetization and electric polarization originating from spin-charge interactions was observed in this system. Our results confirm that Mo2C-FO would be a novel monolayer electromagnetic material, and its magnetization can be modulated by electric polarization.

The importance of perioperative and complication management in the treatment of pheochromocytoma crisis with venoarterial extracorporeal membrane oxygenation (V-A ECMO): a case report and review of the literature.

PURPOSE: In this article, we aimed to elaborate on perioperative and complication management in treatment of pheochromocytoma crisis with extracorporeal membrane oxygenation (ECMO). MATERIAL AND METHODS: We report a case of relatively rare grant paraganglioma-induced pheochromocytoma crisis leading to severe circulatory failure, treated with venoarterial extracorporeal membrane oxygenation (V-A ECMO) as a bridge to curative adrenalectomy. Weaning of ECMO was followed by successful surgical removal of the tumor, and patient survival. However, distal ischemia of the cannulated leg occurred during ECMO operation, which eventually led to amputation. In addition, the patient developed new cerebral infarction and left hemiplegia, half a month after paraganglioma resection. CONCLUSIONS: We believe that patients with pheochromocytoma crisis, who cannot maintain blood circulation, are eligible for V-A ECMO treatment. Moreover, care should be taken to prevent thrombosis and individualized and precise blood pressure management targets. Early detection and treatment of thrombosis is imperative to long-term prognosis of patients with ECMO.

[Research Progress in Clinical Electrophysiological Assessment of Patients with Sepsis-Associated Encephalopathy].

Sepsis-associated encephalopathy(SAE) caused by infections outside the central nervous system always presents extensive brain damage.It is common in clinical practice and associated with a poor prognosis.There are problems in the assessing and diagnosing of SAE.Many factors,such as sedation and mechanical ventilation,make it difficult to assess SAE,while electrophysiological examination may play a role in the assessment.We reviewed the studies of electrophysiological techniques such as electroencephalography and somatosensory evoked potentials for monitoring SAE,hoping to provide certain evidence for the clinical evaluation and diagnosis of SAE.

Identification of sepsis-associated encephalopathy risk factors in elderly patients: a retrospective observational cohort study.

BACKGROUND: Sepsis-associated encephalopathy (SAE) is a severe complication of sepsis that affects upwards of half of all sepsis patients. Few studies have examined the etiology and risk factors of SAE among elderly patients. This study was designed to explore the epidemiology of SAE and the risk factors associated with its development in elderly populations. METHODS: This was a retrospective analysis of elderly sepsis patients admitted to our intensive care unit between January 2017 and January 2022. We then compared non-SAE and SAE groups concerning baseline clinicopathological findings, underlying diseases, infection site, disease type, disease severity, biochemical findings, and 28-day mortality. We further stratified patients in the SAE group based on whether or not they survived for 28 days, and we compared the above data between these groups. RESULTS: Of the 222 elderly sepsis patients, 132 (59.46%) had SAE. SAE patients were found to be significantly older than non-SAE patients. Both age and blood sodium concentrations were found to be associated with SAE risk, while elderly sepsis patients without underlying chronic obstructive pulmonary disease (COPD) have a relatively higher risk of developing SAE. The SAE group also had a significantly higher rate of 28-day mortality, and sequential organ failure assessment (SOFA) scores were a risk factor associated with 28-day mortality. DISCUSSION: Among elderly sepsis patients, SAE risk increases with advancing age, higher blood sodium concentrations, and without underlying COPD. SAE incidence is associated with a poorer prognosis, and SOFA scores are independent predictors of increased mortality among elderly SAE patients.

Numerical Simulation and Experimental Verification of Droplet Generation in Microfluidic Digital PCR Chip.

The generation of droplets is one of the most critical steps in the droplet digital polymerase chain reaction (ddPCR) procedure. In this study, the mechanism of droplet formation in microchannel structure and factors affecting droplet formation were studied. The physical field of laminar two-phase flow level was used to simulate the process of droplet generation through microfluidic technology. The effect of the parameters including flow rate, surface tension, and viscosity on the generated droplet size were evaluated by the simulation. After that, the microfluidic chip that has the same dimension as the simulation was then, fabricated and evaluated. The chip was made by conventional SU-8 photolithography and injection molding. The accuracy of the simulation was validated by comparing the generated droplets in the real scenario with the simulation result. The relative error (RE) between experimentally measured droplet diameter and simulation results under different flow rate, viscosity, surface tension and contact angle was found less than 3.5%, 1.8%, 1.4%, and 1.2%, respectively. Besides, the coefficient of variation (CV) of the droplet diameter was less than 1%, which indicates the experimental droplet generation was of high stability and reliability. This study provides not only fundamental information for the design and experiment of droplet generation by microfluidic technology but also a reliable and efficient investigation method in the ddPCR field.

Phase transition-induced changes in the Raman properties of DMSO/benzene binary systems.

The Raman spectra of dimethylsulfoxide (DMSO)/benzene binary mixtures were studied by decreasing the temperature from 333 K to 263 K with the aim to reveal the molecular interaction properties during phase transition. The intensity of the Raman band for benzene at 992 cm-1 showed an increasing trend in the liquid and solid phases, while it exhibited a highly decreasing trend during the liquid-solid phase transition. The potential energy was calculated to study the effect of intermolecular interaction distance between DMSO and benzene on Raman intensity. The observations indicated that the blueshift of the low-frequency bands of DMSO was significantly different from the redshift of its high-frequency bands. The hydrogen bond generated between DMSO and benzene was well formed in the binary systems. This interaction inducing an enhanced hydrogen bond between the binary systems and attenuated C-H bonds led to opposite Raman shift variations with decreasing temperature. The Raman bands of DMSO at 1425 cm-1, 2899 cm-1, and 2992 cm-1 each split into two peaks after phase transition. The splitting of the Raman bands of DMSO at 1417 cm-1, 2895 cm-1, and 2982 cm-1 cropped up as the temperature dropped to the transformation point of 288 K. This is attributed to the phase transition-induced latent def.(C7) atomic vibrations corresponding to the individual methyl groups of DMSO. The implications of these analyses are expected to be helpful to understand the effect of phase transition on the Raman properties of binary solutions.

A retrospective study of sepsis-associated encephalopathy: epidemiology, clinical features and adverse outcomes.

BACKGROUND: Sepsis-associated encephalopathy (SAE) is a common complication of sepsis that may result in worse outcomes. This study was designed to determine the epidemiology, clinical features, and risk factors of SAE. METHODS: This was a retrospective study of all patients with sepsis who were admitted to the Critical Care Medicine Department of Hangzhou First People's Hospital Affiliated with Zhejiang University School of Medicine from January 2015 to December 2019. RESULTS: A total of 291 sepsis patients were screened, and 127 (43.6%) were diagnosed with SAE. There were significant differences in median age, proportion of underlying diseases such as hypertension, Sequential Organ Failure Assessment (SOFA) score, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, gastrointestinal infections, detection rate of Enterococcus, and 28-day mortality between the SAE and non-SAE groups. Both the SOFA score and APACHE II score were independent risk factors for SAE in patients with sepsis. All 127 SAE patients were divided into survival and non-survival groups. The age, SOFA score, and APACHE II score were independently associated with 28-day mortality in SAE patients. CONCLUSION: In the present retrospective study, nearly half of patients with sepsis developed SAE, which was closely related to poor outcomes. Both the SOFA score and APACHE II score were independent risk factors for predicting the occurrence and adverse outcome of SAE.

Role of mean platelet volume in hypertriglyceridemia-induced acute pancreatitis during pregnancy.

BACKGROUND: Hypertriglyceridemia-induced acute pancreatitis during pregnancy (HTG-APP) is a rare but severe disease with high maternal-fetal mortality risk, which constitutes a systemic inflammatory process accompanied by thrombosis and bleeding disorders. However, the role of mean platelet volume (MPV) in HTG-APP remains unclear. METHODS: In the retrospective study, we collected 45 patients with HTG-APP as the HTG-APP group and 49 pregnant females with hypertriglyceridemia as the control group. MPV and other relevant variables at onset and remission were collected and compared. RESULTS: MPV were significantly higher in the HTG-APP group than in the control group (P < 0.001), and lower in remission than on onset (P = 0.002). According to the severity of acute pancreatitis, all subjects were classified into mild AP (MAP), moderately severe AP (MSAP), and severe AP (SAP) groups. There was a significant difference in MPV on onset among the three groups (P = 0.048), and the SAP patients had the highest levels of MPV. In addition, only in the SAP group, MPV was lower in remission than on onset (P = 0.010). Logistic regression analyses revealed that MPV was significantly associated with SAP (odds ratio = 2.077, 95% confdence interval, 1.038-4.154; P = 0.039). CONCLUSIONS: These results may indicate an important role of mean platelet volume in evaluating the severity of HTG-APP.

Experimental study of different pulse delays on the phenomenon of double shock waves induced by a millisecond-nanosecond combined-pulse laser.

We study the motion morphology, distance, and velocity of plasma and laser-induced shock waves induced by a millisecond-nanosecond (ms-ns) combined-pulse laser with different pulse delays on silicon. The laser shadowgraph method is used, and the phenomenon of double laser-induced shock waves has been found while the pulse delay is 1.2-1.8 ms. The controlling variable method is used to study this phenomenon, and it is found that it is mainly related to the ignition of the laser-supported absorption wave induced by the ms laser. Moreover, the plasma expansion velocity increases with the increase of pulse delay, the axial propagation distance of laser-induced shock waves increases monotonically with pulse delay, and the velocity of laser-induced shock waves decreases with the increase of pulse delay.