Thiol Coordination Softens Liquid Metal Particles To Improve On-Demand Conductivity

Achieving tunable rupturing of eutectic gallium indium (EGaIn) particles holds great significance in flexible electronic applications, particularly pressure sensors. We tune the mechanosensitivity of EGaIn particles by preparing them in toluene with thiol surfactants and demonstrate an improvement over typical preparations in ethanol. We observe, across multiple length scales, that thiol surfactants and the nonpolar solvent synergistically reduce the applied stress requirements for electromechanical actuation. At the nanoscale, dodecanethiol and propanethiol in toluene suppress gallium oxide growth, as characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. Quantitative AFM imaging produces force-indentation curves and height images, while conductive AFM measures current while probing individual EGaIn particles. As the applied force increases, thiolated particles demonstrate intensified softening, rupturing, and stress-induced electrical activation at forces 40% lower than those for bare particles in ethanol. To confirm that thiolation facilitates rupturing at the macroscale, a laser is used to ablate samples of EGaIn particles. Scanning electron microscopy and resistance measurements across macroscopic samples confirm that thiolated EGaIn particles coalesce to exhibit electrical activation at 0.1 W. Particles prepared in ethanol, however, require 3 times higher laser power to demonstrate a similar behavior. This unique collection of advanced techniques demonstrates that our particle synthesis conditions can facilitate on-demand functionality to benefit electronic applications.

Assessing the relative effectiveness of various ultrasound-guided ablation techniques for treating benign thyroid nodules: A systematic review and network meta-analysis

BACKGROUND

Benign thyroid nodules (BTNs) represent a prevalent clinical challenge globally, with various ultrasound-guided ablation techniques developed for their management. Despite the availability of these methods, a comprehensive evaluation to identify the most effective technique remains absent. This study endeavors to bridge this knowledge gap through a network meta-analysis (NMA), aiming to enhance the understanding of the comparative effectiveness of different ultrasound-guided ablation methods in treating BTNs.

METHODS

We comprehensively searched PubMed, Embase, Cochrane, Web of Science, Ovid, SCOPUS, and ProQuest for studies involving 16 ablation methods, control groups, and head-to-head trials. NMA was utilized to evaluate methods based on the percentage change in nodule volume, symptom score, and cosmetic score. This study is registered in INPLASY (registration number 202260061).

RESULTS

Among 35 eligible studies involving 5655 patients, NMA indicated that RFA2 (radiofrequency ablation, 2 sessions) exhibited the best outcomes at 6 months for percentage change in BTN volume (SUCRA value 74.6), closely followed by RFA (SUCRA value 73.7). At 12 months, RFA was identified as the most effective (SUCRA value 81.3). Subgroup analysis showed RFA2 as the most effective for solid nodule volume reduction at 6 months (SUCRA value 75.6), and polidocanol ablation for cystic nodules (SUCRA value 66.5).

CONCLUSION

Various ablation methods are effective in treating BTNs, with RFA showing notable advantages. RFA with 2 sessions is particularly optimal for solid BTNs, while polidocanol ablation stands out for cystic nodules.

Comparison of the antimicrobial photocatalytic activities of SiO2 and Au@SiO2 nanostructures in water decontamination

Photocatalytic disinfection of Escherichia coli suspension by silicon dioxide nanoparticles and silicon dioxide/gold nanocomposite in a batch reactor is investigated experimentally and results are compared. Silica nanoparticles were synthesized by Stöber method and pulsed laser ablation method was employed to prepare gold nanoparticles in distilled water. Composition of two nanoparticles species was carried out, using the second harmonic pulse of Nd:YAG laser, whose wavelength is in the absorption spectra of gold nanoparticles. Results confirm a decrease in the bandgap energy of silica nanoparticles after composition. Escherichia coli were selected as an indicator of the microbial water contamination. Disk diffusion method was used to evaluate the antimicrobial potential of SiO2 and Au@SiO2 nanostructures. Photocatalytic activities of both nanostructures were examined in dark, and under the irradiation of UV and visible light. In all conditions, the performance of Au@SiO2 nanocomposites was higher than SiO2 nanoparticles. In dark condition the higher biocidal nature and activity of Au nanoparticles and for the case of UV radiation, decreasing the bandgap energy and recombination rate of SiO2 nanoparticles after composition with Au increased the efficiency. For the case of visible light radiation, surface plasmon resonances effects, and local heat of Au nanoparticles were responsible for increasing the efficiency. RESEARCH HIGHLIGHTS: Doping large bandgap semiconductors nanostructures, such as silica with metal nanoparticles, such as gold will improve their photocatalytic activity to work in visible light. In this mechanism, gold nanoparticles act as effective traps to prevent the recombination of photogenerated electron-hole pairs. Other mechanisms, such as Schottky barrier formation, surface plasmon resonance absorption of gold nanoparticles, and biocidal nature of the gold nanoparticles are effective in increasing the efficiency of Au doped silica nanostructures.

Increased susceptibility to ischemia causes exacerbated response to microinjuries in the cirrhotic liver

Fractional laser ablation is a technique developed in dermatology to induce remodeling of skin scars by creating a dense pattern of microinjuries. Despite remarkable clinical results, this technique has yet to be tested for scars in other tissues. As a first step toward determining the suitability of this technique, we aimed to (1) characterize the response to microinjuries in the healthy and cirrhotic liver, and (2) determine the underlying cause for any differences in response. Healthy and cirrhotic rats were treated with a fractional laser then euthanized from 0 h up to 14 days after treatment. Differential expression was assessed using RNAseq with a difference-in-differences model. Spatial maps of tissue oxygenation were acquired with hyperspectral imaging and disruptions in blood supply were assessed with tomato lectin perfusion. Healthy rats showed little damage beyond the initial microinjury and healed completely by 7 days without scarring. In cirrhotic rats, hepatocytes surrounding microinjury sites died 4-6 h after ablation, resulting in enlarged and heterogeneous zones of cell death. Hepatocytes near blood vessels were spared, particularly near the highly vascularized septa. Gene sets related to ischemia and angiogenesis were enriched at 4 h. Laser-treated regions had reduced oxygen saturation and broadly disrupted perfusion of nodule microvasculature, which matched the zones of cell death. Our results demonstrate that the cirrhotic liver has an exacerbated response to microinjuries and increased susceptibility to ischemia from microvascular damage, likely related to the vascular derangements that occur during cirrhosis development. Modifications to the fractional laser tool, such as using a femtosecond laser or reducing the spot size, may be able to prevent large disruptions of perfusion and enable further development of a laser-induced microinjury treatment for cirrhosis.

Patient-Reported Outcomes after Laser Ablation for Bladder Tumours Compared to Transurethral Resection-A Prospective Study

The standard procedure for diagnosis and treatment of bladder tumours, transurethral resection of bladder tumour (TURBT), is associated with a complication rate of up to 26% and potentially has severe influence on patient-reported outcomes (PRO). Outpatient transurethral laser ablation (TULA) is an emerging new modality that is less invasive with a lower risk of complications and, thereby, possibly enhanced PRO. We collected PRO following transurethral procedures in treatment of bladder tumours to evaluate any clinically relevant differences in symptoms and side effects. This prospective observational study recruited consecutive patients undergoing different bladder tumour-related transurethral procedures. Patients filled out questionnaires regarding urinary symptoms (ICIQ-LUTS), postoperative side effects, and quality of life (EQ-5D-3L) at days 1 and 14 postoperatively. In total, 108 patients participated. The most frequently reported outcomes were postoperative haematuria and pain. Patients undergoing TURBT reported longer lasting haematuria, a higher perception of pain, and a more negative impact on quality of life compared to patients undergoing TULA. TURBT-treated patients had more cases of acute urinary retention and a higher need for contacting the healthcare system. Side effects following transurethral procedures were common but generally not severe. The early symptom burden following TURBT was more extensive than that following TULA.

Temporo-parieto-occipital disconnection (TPO) by robot-assisted magnetic resonance imaging-guided laser interstitial thermal therapy (MRIgLITT) for refractory epilepsy in a pediatric patient: Proof-of-principle case report and surgical nuances

Magnetic resonance imaging-guided laser interstitial thermal therapy (MRIgLITT) has been proven safe and effective for the treatment of focal epilepsy of different etiologies. It has also been used to disconnect brain tissue in more extensive or diffuse epilepsy, such as corpus callosotomy and hemispherotomy. In this study, we report a case of temporo-parieto-occipital disconnection (TPO) surgery performed using MRIgLITT assisted by a robotic arm for refractory epilepsy of the posterior quadrant. A highly realistic cadaver simulation was performed before the actual surgery. The patient was a 14-year-old boy whose seizures began at the age of eight. The epilepsy was a result of a left perinatal ischemic event that caused a porencephalic cyst, and despite receiving multiple antiepileptic drugs, the patient continued to experience daily seizures which led to the recommendation of surgery. A Wada test lateralized language in the right hemisphere. Motor and sensory function was confirmed in the left hemisphere through MRI functional studies and NexStim®. The left MRIgLITT TPO disconnection was achieved using five laser fibers. The patient followed an excellent postoperative course and was seizure-free, with no additional neurological deficits 24 months after the surgery.

Plasmonic effect of metal nanoparticles on the photocatalytic properties of TiO2/rGO composite

In this work, the plasmonic effect of Au and Ag nanoparticles in the heterostructure photocatalyst system (TiO2/rGO) was studied. The laser ablation approach was applied to synthesize Au and Ag nanoparticles to eliminate impurity influence in this plasmonic study. Characterizing tools such as SEM, TEM, XRD, Raman, UV-vis spectral techniques were applied to obtain morphological information and optical properties of the nanocomposites. Photocatalytic properties of ternary nanocomposities such as, TiO2/rGO/Ag and TiO2/rGO/Au, were evaluated against Methylene blue and Congo red dyes with changing concentration of plasmonic nanoparticles (Au and Ag) and it was founded that the nanocomposite with the concentration of 10-11 mol/L Au NPs in TiO2/rGO has the best photocatalytic activity. EIS study indicated that a significant decrease in resistance Rp (109 Ohms) was observed for TiO2/rGO at 10-11 mol/Lconcentration of Au and its lifetimes is 0.0118 s, supporting that TiO2/rGO/Au has the best photocatalytic activity at 10-11 mol/L Au in the TiO2/rGO nanocomposites.

Linear Capacitive Pressure Sensor with Gradient Architecture through Laser Ablation on MWCNT/Ecoflex Film

The practical application of flexible pressure sensors, including electronic skins, wearable devices, human-machine interaction, etc., has attracted widespread attention. However, the linear response range of pressure sensors remains an issue. Ecoflex, as a silicone rubber, is a common material for flexible pressure sensors. Herein, we have innovatively designed and fabricated a pressure sensor with a gradient micro-cone architecture generated by CO2 laser ablation of MWCNT/Ecoflex dielectric layer film. In cooperation with the gradient micro-cone architecture and a dielectric layer of MWCNT/Ecoflex with a variable high dielectric constant under pressure, the pressure sensor exhibits linearity (R2 = 0.990) within the pressure range of 0-60 kPa, boasting a sensitivity of 0.75 kPa-1. Secondly, the sensor exhibits a rapid response time of 95 ms, a recovery time of 129 ms, hysteresis of 6.6%, and stability over 500 cycles. Moreover, the sensor effectively exhibited comprehensive detection of physiological signals, airflow detection, and Morse code communication, thereby demonstrating the potential for various applications.

Resurfacing of atrophic facial acne scars with a multimodality CO2 and 1570 nm laser system

BACKGROUND

Scarring is one of the most prevalent long-term complications of acne vulgaris and has cosmetic, psychological, and social burdens. Contemporary management programs integrate multiple modalities to best address the multiple factors underlying their development and persistence. This work assessed the impact of sequential multimodal laser therapy on acne scar geometrics and texture.

METHODS

Adult patients (n = 16) with Fitzpatrick skin type II-IV and presenting with facial acne scars, underwent three combination ablative (CO2), and nonablative (1570 nm) laser treatment sessions at two-month intervals. Treatment was delivered using a ProScan Hybrid applicator, with each regimen including illumination with both ablative and a nonablative lasers applied in a grid mode sequence. Scar microtopography was assessed at baseline and 6 months after the last treatment session.

RESULTS

At baseline, all patients had both box and rolling scars, while only three had icepick scars. Six months following treatment, mean scar volume improved from 5.7 ± 5.2 mm3 at baseline to 3.1 ± 3.0 mm3 and mean affected area improved from 165.6 ± 134.0 mm2 94.0 ± 80.1 mm2, translating to 47.0 ± 7.9% and 43.2 ± 8.6% reductions from baseline, respectively. Patients were highly satisfied with treatment outcomes, and no serious adverse reactions were documented during the course of treatment or follow-up.

CONCLUSION

Multimodal CO2 and 1570-nm laser treatment improved the surface profilometry of patients with atrophic facial acne scars. Customization of both treatment intervals and laser settings to cosmetic regions, scar profiles and skin phototypes may further enhance treatment outcomes and expand its applicability to additional skin deformities.

Proactive esophageal cooling during laser cardiac ablation: A computer modeling study

BACKGROUND AND OBJECTIVES

Laser ablation is increasingly used to treat atrial fibrillation (AF). However, atrioesophageal injury remains a potentially serious complication. While proactive esophageal cooling (PEC) reduces esophageal injury during radiofrequency ablation, the effects of PEC during laser ablation have not previously been determined. We aimed to evaluate the protective effects of PEC during laser ablation of AF by means of a theoretical study based on computer modeling.

METHODS

Three-dimensional mathematical models were built for 20 different cases including a fragment of atrial wall (myocardium), epicardial fat (adipose tissue), connective tissue, and esophageal wall. The esophagus was considered with and without PEC. Laser-tissue interaction was modeled using Beer-Lambert's law, Pennes' Bioheat equation was used to compute the resultant heating, and the Arrhenius equation was used to estimate the fraction of tissue damage (FOD), assuming a threshold of 63% to assess induced necrosis. We modeled laser irradiation power of 8.5 W over 20 s. Thermal simulations extended up to 250 s to account for thermal latency.

RESULTS

PEC significantly altered the temperature distribution around the cooling device, resulting in lower temperatures (around 22°C less in the esophagus and 9°C in the atrial wall) compared to the case without PEC. This thermal reduction translated into the absence of transmural lesions in the esophagus. The esophagus was thermally damaged only in the cases without PEC and with a distance equal to or shorter than 3.5 mm between the esophagus and endocardium (inner boundary of the atrial wall). Furthermore, PEC demonstrated minimal impact on the lesion created across the atrial wall, either in terms of maximum temperature or FOD.

CONCLUSIONS

PEC reduces the potential for esophageal injury without degrading the intended cardiac lesions for a variety of different tissue thicknesses. Thermal latency may influence lesion formation during laser ablation and may play a part in any collateral damage.

Laser-Synthesized Germanium Nanoparticles as Biodegradable Material for Near-Infrared Photoacoustic Imaging and Cancer Phototherapy

Biodegradable nanomaterials can significantly improve the safety profile of nanomedicine. Germanium nanoparticles (Ge NPs) with a safe biodegradation pathway are developed as efficient photothermal converters for biomedical applications. Ge NPs synthesized by femtosecond-laser ablation in liquids rapidly dissolve in physiological-like environment through the oxidation mechanism. The biodegradation of Ge nanoparticles is preserved in tumor cells in vitro and in normal tissues in mice with a half-life as short as 3.5 days. Biocompatibility of Ge NPs is confirmed in vivo by hematological, biochemical, and histological analyses. Strong optical absorption of Ge in the near-infrared spectral range enables photothermal treatment of engrafted tumors in vivo, following intravenous injection of Ge NPs. The photothermal therapy results in a 3.9-fold reduction of the EMT6/P adenocarcinoma tumor growth with significant prolongation of the mice survival. Excellent mass-extinction of Ge NPs (7.9 L g-1 cm-1 at 808 nm) enables photoacoustic imaging of bones and tumors, following intravenous and intratumoral administrations of the nanomaterial. As such, strongly absorbing near-infrared-light biodegradable Ge nanomaterial holds promise for advanced theranostics.

Preclinical assessment of a noncooled MR thermometry-based neurosurgical laser therapy system

OBJECTIVE

MRI-guided laser interstitial thermal therapy (MRgLITT) has recently gained interest as an ablative stereotactic procedure for intractable epilepsy, movement disorders, and brain tumors. Conventionally, a LITT system consists of a laser generator and cooled laser applicator, which is a fiber optic core surrounded by a sheath through which cooled fluid is pumped. However, this footprint can make the system bulky and nonmobile, limit the maximum depth of targeting, and increase the chances of breakdown. Herein, the authors conduct a preclinical assessment of a noncooled MRgLITT system in a porcine model.

METHODS

Three-tesla MRI was used to guide the in vivo placement of noncooled laser applicators in the porcine brain. The study consisted of a survival arm and terminal arm. The laser was activated at a power of 4-7 W for ≤ 180 seconds. Temperature changes were monitored using the MR thermometry software ThermoGuide in the survival arm (n = 5) or both ThermoGuide software and adjacently inserted thermal probes in the terminal arm (n = 3). Thermal damage was determined by the software using the temperature-time relationship of cumulative equivalent minutes at 43°C (CEM43). Temperatures calculated by the software were compared with those recorded by the temperature probes. The dimensions of thermal damage thresholds (TDTs; 2-9, 10-59, 60-239, ≥ 240 CEM43 isolines) given by MR thermometry were compared with the dimensions of irreversible damage on histopathological analysis.

RESULTS

There was a strong correlation between temperature recordings by ThermoGuide and those by thermal probes at both 4 mm (r = 0.96) and 8 mm (r = 0.80), with a mean absolute error of 0.76°C ± 2.13°C and 0.17°C ± 1.65°C at 4 and 8 mm, respectively. The area of 2-9 CEM43 was larger than the area of irreversible damage seen on histopathological analysis. The dimensions of the 10 and 60 CEM43 correlated well with dimensions of the lesion on histopathological analysis. A well-defined border (≤ 1 mm) was observed between the area of irreversible damage and healthy brain tissue.

CONCLUSIONS

This preclinical assessment showed that the noncooled LITT system was able to precisely reach the target and create well-defined lesions within a margin of safety, without any adverse effects. MR thermometry software provided an accurate near-real-time temperature of the brain tissue, and dimensions of the lesion as visualized by the software correlated well with histopathological findings. Further studies to test the system's efficacy and safety in human subjects are in progress.

Laser direct overall water splitting for H2 and H2O2 production

Hydrogen (H2) and hydrogen peroxide (H2O2) play crucial roles as energy carriers and raw materials for industrial production. However, the current techniques for H2 and H2O2 production rely on complex catalysts and involve multiple intermediate steps. In this study, we present a straightforward, environmentally friendly, and highly efficient laser-induced conversion method for overall water splitting to simultaneously generate H2 and H2O2 at ambient conditions without any catalysts. The laser direct overall water splitting approach achieves an impressive light-to-hydrogen energy conversion efficiency of 2.1%, with H2 production rates of 2.2 mmol/h and H2O2 production rates of 65 µM/h in a limited reaction area (1 mm2) within a short real reaction time (0.36 ms/h). Furthermore, we elucidate the underlying physics and chemistry behind the laser-induced water splitting to produce H2 and H2O2. The laser-induced cavitation bubbles create an optimal microenvironment for water-splitting reactions because of the transient high temperatures (104 K) surpassing the chemical barrier required. Additionally, their rapid cooling rate (1010 K/s) hinders reverse reactions and facilitates H2O2 retention. Finally, upon bubble collapse, H2 is released while H2O2 remains dissolved in the water. Moreover, a preliminary amplification experiment demonstrates the potential industrial applications of this laser chemistry. These findings highlight that laser-based production of H2 and H2O2 from water holds promise as a straightforward, environmentally friendly, and efficient approach on an industrial scale beyond conventional chemical catalysis.

Improved Water Collection from Short-Term Fog on a Patterned Surface with Interconnected Microchannels

Fog harvesting is considered a promising freshwater collection strategy for overcoming water scarcity, because of its environmental friendliness and strong sustainability. Typically, fogging occurs briefly at night and in the early morning in most arid and semiarid regions. However, studies on water collection from short-term fog are scarce. Herein, we developed a patterned surface with highly hydrophilic interconnected microchannels on a superhydrophobic surface to improve droplet convergence driven by the Young-Laplace pressure difference. With a rationally designed surface structure, the optimized water collection rate from mild fog could reach up to 67.31 g m-2 h-1 (6.731 mg cm-2 h-1) in 6 h; this value was over 130% higher than that observed on the pristine surface. The patterned surface with interconnected microchannels significantly shortened the startup time, which was counted from the fog contact to the first droplet falling from the fog-harvesting surface. The patterned surface was also facilely prepared via a controllable strategy combining laser ablation and chemical vapor deposition. The results obtained in outdoor environments indicate that the rationally designed surface has the potential for short-term fog harvesting. This work can be considered as a meaningful attempt to address the practical issues encountered in fog-harvesting research.

Merging of Bi-Modality of Ultrafast Laser Processing: Heating of Si/Au Nanocomposite Solutions with Controlled Chemical Content

Ultrafast laser processing possesses unique outlooks for the synthesis of novel nanoarchitectures and their further applications in the field of life science. It allows not only the formation of multi-element nanostructures with tuneable performance but also provides various non-invasive laser-stimulated modalities. In this work, we employed ultrafast laser processing for the manufacturing of silicon-gold nanocomposites (Si/Au NCs) with the Au mass fraction variable from 15% (0.5 min ablation time) to 79% (10 min) which increased their plasmonic efficiency by six times and narrowed the bandgap from 1.55 eV to 1.23 eV. These nanostructures demonstrated a considerable fs laser-stimulated hyperthermia with a Au-dependent heating efficiency (~10-20 °C). The prepared surfactant-free colloidal solutions showed good chemical stability with a decrease (i) of zeta (ξ) potential (from -46 mV to -30 mV) and (ii) of the hydrodynamic size of the nanoparticles (from 104 nm to 52 nm) due to the increase in the laser ablation time from 0.5 min to 10 min. The electrical conductivity of NCs revealed a minimum value (~1.53 µS/cm) at 2 min ablation time while their increasing concentration was saturated (~1012 NPs/mL) at 7 min ablation duration. The formed NCs demonstrated a polycrystalline Au nature regardless of the laser ablation time accompanied with the coexistence of oxidized Au and oxidized Si as well as gold silicide phases at a shorter laser ablation time (<1 min) and the formation of a pristine Au at a longer irradiation. Our findings demonstrate the merged employment of ultrafast laser processing for the design of multi-element NCs with tuneable properties reveal efficient composition-sensitive photo-thermal therapy modality.

Comparison of magnetic resonance-guided laser interstitial thermal therapy corpus callosum ablation to open microsurgical corpus callosotomy: A single-center retrospective cohort study

OBJECTIVE

Corpus callosotomy (CC) is an important treatment for atonic seizures in patients with generalized or multifocal drug-resistant epilepsy (DRE). Traditionally, CC is performed via an open microsurgical approach, but more recently, MR-guided stereotactic laser interstitial thermal therapy (LITT) corpus callosum ablation (CCA) has been developed to leverage the safety and minimally invasive nature of LITT. Given the recent adoption of CCA at select centers, how CCA compares to CC is unknown. We aim to compare the clinical seizure outcomes of CCA and CC after extended follow-up.

METHODS

We performed a retrospective cohort study to compare the effectiveness and safety of CC to CCA from 1994 to 2022. The primary outcome was a 50% reduction in target seizure. Secondary outcome measures were postoperative length of stay, adverse events, and other effectiveness metrics. Comparative statistics were executed using Stata. Normality for continuous variables was assessed, and parametric statistics were utilized as needed. Frequency was compared with chi-squared or Fischer's exact tests, when applicable.

RESULTS

Data from 47 operations performed on 36 patients were included in this study, of which 13 (36%) patients underwent 17 CCA. Patients who received CCA had similar rates of meaningful reduction (>50%) of atonic seizures as their CC counterparts (55% vs 70% P = 0.15). Patients undergoing CCA had significantly shorter hospitalizations than those receiving CC (2.5 vs 6.0 days P < 0.001). There was no significant difference in rates of postoperative complications between the groups, although the magnitude of the complication rates was lower in the CCA cohort (12% vs 28%).

SIGNIFICANCE

This early experience suggests CCA has similar outcomes to traditional CC, albeit with a shorter hospital stay. However, future studies are necessary to investigate the noninferiority between these two approaches. Large multicenter studies are necessary to investigate differences in adverse events and whether these findings generalize across other centers.

Cytotoxicity of Laser-Synthesized Nanoparticles of Elemental Bismuth

High X-ray absorption combined with photothermal properties make bismuth nanoparticles (Bi NP) a promising agent for multimodal cancer theranostics. However, the synthesis of Bi NP by the "classical" chemical methods has numerous limitations, including potential toxicity of the produced nanomaterials. Here we studied in vitro toxicity of laser-synthesized Bi NP coated with Pluronic F-127 on mouse fibroblast cell line L929. The survival of L929 cells decreased linearly with increasing the concentration of Bi NP in a concentration range of 3-500 μg/ml; the LC50 value was 57 μg/ml. The unique combination of functional properties and moderate toxicity of the laser-synthesized Bi NP makes them a new promising platform for sensitization of multimodal cancer theranostics.

Optimizing Sensor Placement for Temperature Mapping during Ablation Procedures

Accurately mapping the temperature during ablation is crucial for improving clinical outcomes. While various sensor configurations have been suggested in the literature, depending on the sensors' type, number, and size, a comprehensive understanding of optimizing these parameters for precise temperature reconstruction is still lacking. This study addresses this gap by introducing a tool based on a theoretical model to optimize the placement of fiber Bragg grating sensors (FBG) within the organ undergoing ablation. The theoretical model serves as a general framework, allowing for adaptation to various situations. In practical application, the model provides a foundational structure, with the flexibility to tailor specific optimal solutions by adjusting problem-specific data. We propose a nonlinear and nonconvex (and, thus, only solvable in an approximated manner) optimization formulation to determine the optimal distribution and three-dimensional placement of FBG arrays. The optimization aims to find a trade-off among two objectives: maximizing the variance of the expected temperatures measured by the sensors, which can be obtained from a predictive simulation that considers both the type of applicator used and the specific organ involved, and maximizing the squared sum of the distances between the sensor pairs. The proposed approach provides a trade-off between collecting diverse temperatures and not having all the sensors concentrated in a single area. We address the optimization problem through the utilization of approximation schemes in programming. We then substantiate the efficacy of this approach through simulations. This study tackles optimizing the FBGs' sensor placement for precise temperature monitoring during tumor ablation. Optimizing the FBG placement enhances temperature mapping, aiding in tumor cell eradication while minimizing damage to surrounding tissues.

Cystoscopic-guided laser ablation of intramural ectopic ureters in a female cat

Case summary

An 8-month-old female spayed domestic shorthair cat was presented for chronic urinary incontinence (UI). Since being adopted 6 months earlier, the cat had a history of urine leakage during both activity and rest. Baseline blood work and urine culture showed no significant abnormalities and no evidence of a urinary tract infection. An abdominal CT with excretory urography followed by a focal urinary tract ultrasound revealed a suspected right intramural ectopic ureter (EU) and potential left EU. Cystoscopy confirmed bilateral intramural EUs. Cystoscopic-guided laser ablation (CLA) of both EUs was performed. The cat developed temporary urinary obstruction (UO) 36 h after the procedure, which was medically managed with prazosin and buprenorphine. Ultimately, the cat's urinary signs completely resolved with no UI recognized after the procedure and the cat has remained continent during 18 months of follow-up.

Relevance and novel information

CLA of intramural EUs is routinely performed in dogs, but this technique has not been previously reported in cats with this condition. Although post-procedural urinary tract signs were initially present, the cat ultimately had an excellent outcome with resolution of UI after this procedure.

Transperineal laser ablation as treatment for benign prostatic obstruction: Safety, feasibility and functional outcomes-A pilot study

Background

Standard surgical treatment for lower urinary tract symptoms (LUTS) due to benign prostatic obstruction (BPO) requires anaesthesia and hospitalization. Transperineal laser ablation (TPLA) is a novel minimally invasive treatment for BPO, which has been performed using local anaesthetics and conscious sedation.

Objectives

The aim of this study is to assess safety, feasibility and functional outcomes of TPLA for the treatment of LUTS in men fit also for standard surgery.

Methods

This prospective, multicentre, interventional pilot study included 20 patients. Eligible patients were men ≥40 years of age, with urodynamically proven bladder outlet obstruction, a peak urinary flow of 5-15 mL/s and a prostate volume of 30-120 cc. All subjects underwent Soractelite™ TPLA using the Echolaser® X4 system. Two to four fibres were placed in the prostate, whereafter laser light induced coagulative necrosis. Twelve months of follow-up included uroflowmetry, an ultrasound of the prostate and PROMs (IPSS and IIEF).

Results

Twenty patients were treated with TPLA using local anaesthetics and optional sedation. Sixteen patients were treated in an outpatient setting, using only local anaesthetics in 12 of them; four were treated in the operating room, whereof two under general anaesthesia. No device related adverse events occurred, nor did any grade ≥3 adverse events during follow-up. Post-TPLA, 10 men continued spontaneous voiding, and 10 men developed a urinary retention treated by a temporary indwelling catheter for 15.2 ± 3.5 days. At 12 months, Qmax improved from 9.7 ± 3.5 to 14.9 ± 6.0 (p = 0.015), IPSS improved from 21.3 ± 5.2 to 10.9 ± 5.5 (p < 0.0001), QoL improved from 4.9 ± 0.9 to 1.9 ± 1.1 (p < 0.0001), IIEF-15 total score remained stable and 11/13 patients (85%) preserved antegrade ejaculation.

Conclusions

TPLA is a safe and feasible treatment for men with LUTS due to BPO. TPLA can be performed in an outpatient setting under only local anaesthetics. Functional and quality of life outcomes improved significantly at 12 months, and erectile function remained stable.

Core PCP mutations affect short-time mechanical properties but not tissue morphogenesis in the Drosophila pupal wing

How morphogenetic movements are robustly coordinated in space and time is a fundamental open question in biology. We study this question using the wing of Drosophila melanogaster, an epithelial tissue that undergoes large-scale tissue flows during pupal stages. Previously, we showed that pupal wing morphogenesis involves both cellular behaviors that allow relaxation of mechanical tissue stress, as well as cellular behaviors that appear to be actively patterned (Etournay et al., 2015). Here, we show that these active cellular behaviors are not guided by the core planar cell polarity (PCP) pathway, a conserved signaling system that guides tissue development in many other contexts. We find no significant phenotype on the cellular dynamics underlying pupal morphogenesis in mutants of core PCP. Furthermore, using laser ablation experiments, coupled with a rheological model to describe the dynamics of the response to laser ablation, we conclude that while core PCP mutations affect the fast timescale response to laser ablation they do not significantly affect overall tissue mechanics. In conclusion, our work shows that cellular dynamics and tissue shape changes during Drosophila pupal wing morphogenesis do not require core PCP as an orientational guiding cue.

Improvement of Metal-Doped β-TCP Scaffolds for Active Bone Substitutes via Ultra-Short Laser Structuring

Various efforts have been made to develop antibacterial biomaterials capable of also sustaining bone remodulation to be used as bone substitutes and reduce patient infection rates and related costs. In this work, beta-tricalcium phosphate (β-TCP) was chosen due to its known biocompatibility and use as a bone substitute. Metal dopants were incorporated into the crystal structure of the β-TCP, and disks were produced from this material. Magnesium and strontium, as well as copper and silver, were chosen as dopants to improve the osteogenic and antibacterial properties, respectively. The surface of the β-TCP samples was further modified using a femtosecond laser system. Grid and line patterns were produced on the plates' surface via laser ablation, creating grooves with depths lower than 20 μm and widths between 20 and 40 μm. Raman and FTIR analysis confirmed that laser ablation did not result in the degradation or phase change of the materials, making it suitable for surface patterning. Laser ablation resulted in increased hydrophilicity of the materials, as the control samples (non-ablated samples) have WCA values ranging from 70° to 93° and become, upon laser ablation, superwicking surfaces. Confocal measurements show an increase in specific surface area of 50% to 200% compared to the control. Overall, the results indicate the potential of laser ablation to improve the surface characteristics of β-TCP, which may lead to an improvement in the antibacterial and osteogenic properties of the produced materials.

Monte Carlo Approach to the Evaluation of Nanoparticles Size Distribution from the Analysis of UV-Vis-NIR Spectra

How nice would it be to obtain the size distribution of a nanoparticle dispersion fast and without electron microscope measurements? UV-Vis-NIR spectrophotometry offers a very rapid solution; however, the spectra interpretation can be very challenging and needs to take into account the size distribution of the nanoparticles and agglomeration. This work suggests a Monte Carlo method for rapid fitting UV-Vis-NIR spectra using one or two size distributions starting from a dataset of precomputed spectra based on Mie theory. The proposed algorithm is tested on copper nanoparticles produced with Pulsed Laser Ablation in Liquid and on gold nanoparticles from the literature. The fitted distribution results are comparable with Transmission Electron Microscope results and, in some cases, reflect the presence of agglomeration.

Efficacy and safety of ultrasound-guided radiofrequency, microwave and laser ablation for the treatment of T1N0M0 papillary thyroid carcinoma on a large scale: a systematic review and meta-analysis

BACKGROUND

To analyze the efficacy and safety of radiofrequency ablation (RFA), microwave ablation (MWA) and laser ablation (LA) in T1N0M0 papillary thyroid carcinoma (PTC) patients by evaluating data on several outcomes on a large scale.

MATERIALS AND METHODS

Literature searches were conducted in PUBMED, EMBASE and the Cochrane Library for studies of thermal ablation (TA) for treating T1N0M0 PTC. Data on the volume reduction rate (VRR) at the 12-month follow-up and final follow-up, complete disappearance rate, local recurrence rate, lymph node metastasis rate, and complication rate of RFA, MWA and LA were evaluated separately. RFA effects were compared between T1aN0M0 and T1bN0M0 patients.

RESULTS

A total of 36 eligible studies were included. RFA presented superior efficacy than MWA in 12-month VRR. At the final follow-up, the difference was slight in subgroups, showing a significant reduction. The complete disappearance rate of LA (93.00%) was higher than that of RFA (81.00%) and MWA (71.00%). Additionally, the local recurrence rate pooled proportions of MWA and RFA were both 2.00%, lower than that of the LA group (3.00%). There was no event of distant metastasis. The lymph node metastasis rates were similar, as RFA (1.00%) had the lowest. For minor complication rates, the pooled proportions of RFA (3.00%) were smaller than those of LA (6.00%) and MWA (13.00%). T1aN0M0 lesions presented with better outcomes than T1bN0M0 lesions.

CONCLUSION

RFA, MWA and LA were reliable in curing PTC, and RFA presented advantages in most outcomes. T1aN0M0 patients may experience fewer side effects than T1bN0M0 patients.

Versatile On-Chip Programming of Circuit Hardware for Wearable and Implantable Biomedical Microdevices

Wearable and implantable microscale electronic sensors have been developed for a range of biomedical applications. The sensors, typically millimeter size silicon microchips, are sought for multiple sensing functions but are severely constrained by size and power. To address these challenges, a hardware programmable application-specific integrated circuit design is proposed and post-process methodology is exemplified by the design of battery-less wireless microchips. Specifically, both mixed-signal and radio frequency circuits are designed by incorporating metal fuses and anti-fuses on the top metal layer to enable programmability of any number of features in hardware of the system-on-chip (SoC) designs. This is accomplished in post-foundry editing by combining laser ablation and focused ion beam processing. The programmability provided by the technique can significantly accelerate the SoC chip development process by enabling the exploration of multiple internal circuit parameters without the requirement of additional programming pads or extra power consumption. As examples, experimental results are described for sub-millimeter size complementary metal-oxide-semiconductor microchips being developed for wireless electroencephalogram sensors and as implantable microstimulators for neural interfaces. The editing technique can be broadly applicable for miniaturized biomedical wearables and implants, opening up new possibilities for their expedited development and adoption in the field of smart healthcare.

Effects of Ultrasound-Guided Laser Ablation Therapy on Symptomatic Benign Thyroid Nodules, Using EchoLaser - Results of a Pilot Study in the United States

OBJECTIVE

To evalate the efficacy of single ultrasound-guided laser ablation treatment on symptomatic benign thyroid nodules in outpatient setting, we conducted a single-center, prospective, nonrandomized, open label interventional study.

METHODS

This study included adults with normal thyroid function and symptomatic thyroid nodules measuring >29 mm and ≤60 mm with <20% cystic area by ultrasound. Laser ablation energy was calculated based on device guidelines. A single nodule was treated under local anesthesia. Each application session lasted between 400 and 600 seconds under a laser power output of 3 W.

RESULTS

Ten subjects underwent the procedure and 9 subjects completed 12-month follow-up. Baseline thyroid nodule volumes ranged from 5.51 to 28.22 mL and the total energy delivered ranged from 1477.00 to 7206.50 J. The average nodule volume reduction at 12 months after procedure for 9 patients was 71.087%. Nodules were visible from >1 m away at baseline for all 10 subjects and not visible in 8 of 10 at 3 months and 6 of 9 subjects at 12 months. Most subjects reported that they would likely undergo the procedure again. No significant adverse events were reported.

CONCLUSION

This study demonstrated the feasibility of performing laser ablation in a clinical setting in the United States. Reduction in nodule volume and symptoms were observed, and the procedure was tolerated well by the subjects.

A blast from the past: Understanding stem cell specification in plant roots using laser ablation

In the Arabidopsis root, growth is sustained by the meristem. Signalling from organiser cells, also termed the quiescent centre (QC), is essential for the maintenance and replenishment of the stem cells. Here, we highlight three publications from the founder of the concept of the stem cell niche in Arabidopsis and a pioneer in unravelling regulatory modules governing stem cell specification and maintenance, as well as tissue patterning in the root meristem: Ben Scheres. His research has tremendously impacted the plant field. We have selected three publications from the Scheres legacy, which can be considered a breakthrough in the field of plant developmental biology. van den Berg et al. (1995) and van den Berg et al. (1997) uncovered that positional information-directed patterning. Sabatini et al. (1999), discovered that auxin maxima determine tissue patterning and polarity. We describe how simple but elegant experimental designs have provided the foundation of our current understanding of the functioning of the root meristem.

Femtosecond Laser Machining of an X-ray Mask in a 500 Micron-Thick Tungsten Sheet

Femtosecond laser material processing (FLMP) was used to make an X-ray mask in a 500 µm thick tungsten sheet without the use of any chemical etch methods. The laser produced an 800 nm wavelength at a 1 kHz repetition rate and a pulse width of 100 fs. The laser beam arrival at the tungsten sheet was synchronized to a computer numerically controlled (CNC) stage that allowed for motion in the XYZθ directions. The X-ray mask design was made using CAD/CAM software (Alphacam 2019 R1) and it consisted of linear, circular, and 45° angle features that covered an area of 10 mm × 10 mm. A total of 70 laser beam passes at a moderate laser energy of 605.94 J/cm2 were used to make through-cut features into the tungsten sheet. The morphology of the top view (laser incident, LS) images showed cleaner and smoother cut edges relative to the bottom view (laser exit, LE) images. It was found that the size dimensions of the through-cut features on the LE surfaces were better aligned with the CAD dimensions than those of the LS surfaces. The focused laser beam produced inclined cut surfaces as the beam made the through cut from the LS to the LE of the tungsten sheet. The circular features at the LS surface deviated toward being oval-like on the LE surface, which could be compensated for in future CAD designs. The dependence of the CNC processing speed on the thickness of the etch depth was determined to have a third-order exponential decay relationship, thereby producing a theoretical model that will be useful for future investigators to predict the required experimental parameters needed to achieve a known etch depth in tungsten. This is the first study that has demonstrated the capability of using a femtosecond laser to machine through-cut an X-ray mask in a 500 µm thick tungsten sheet with no involvement of a wet etch or any other such supporting process.

Stereoelectroencephalography-guided laser ablation in neocortical epilepsy: Electrophysiological correlations and outcome

OBJECTIVE

We aimed to study the correlation between seizure outcomes in patients with drug-resistant epilepsy (DRE) who underwent laser interstitial thermal therapy (LITT) and stereoelectroencephalographic electrophysiologic patterns with respect to the extent of laser ablation.

METHODS

We retrospectively analyzed 16 consecutive DRE patients who underwent LITT. A seizure onset zone (SOZ) was obtained from multidisciplinary patient management conferences and again was confirmed independently by two epileptologists based on conventional analysis. SOZs were retrospectively divided into localized, lobar and multilobar, and nonlocalized onset types. A posteriori-predicted epileptogenic zone (PEZ) was identified using the previously developed "EZ fingerprint" pipeline. The completeness of the SOZ and PEZ ablation was compared and correlated with the duration of seizure freedom (SF).

RESULTS

Of 16 patients, 11 had an a posteriori-identified PEZ. Three patients underwent complete ablation of SOZ with curative intent, and the other 13 with palliative intent. Of three patients with complete ablation of the SOZ, two had concordant PEZ and SOZ and achieved 40- and 46-month SF without seizure recurrence. The remaining patient, without any PEZ identified, had seizure recurrence within 1 month. Six of 13 patients with partial ablation of the SOZ and PEZ achieved mean seizure freedom of 19.8 months (range = 1-44) with subsequent seizure recurrence. The remaining seven patients had partial ablation of the SOZ without the PEZ identified or ablation outside the PEZ with seizure recurrence within 1-2 months, except one patient who had 40-month seizure freedom after ablation of periventricular heterotopia.

SIGNIFICANCE

Only complete ablation of the well-restricted SOZ concordant with the PEZ was associated with long-term SF, whereas partial ablation of the PEZ might lead to SF with eventual seizure recurrence. Failure to identify PEZ and ablation limited to the SOZ often led to 1-2 months of SF.

Ablation of cervical inlet patch for the treatment of globus sensation: A case report

We present a case of a medically resistant cervical inlet patch causing persistent globus and symptoms of laryngo-pharyngeal reflux, successfully treated with CO2 laser ablation.

Auxin Involvement in Ceratopteris Gametophyte Meristem Regeneration

Growth and development of the Ceratopteris hermaphroditic gametophytes are dependent on cell proliferation in the marginal meristem, which when destroyed will regenerate at a new location on the body margin. We established a laser ablation method to destroy a single initial cell in the meristem. Ablation caused the cessation of cell proliferation accompanied by the disappearance of the expression of an auxin synthesis gene (CrTAA2) and a cell proliferation marker gene (CrWOXB). New meristem regeneration occurred within a predictable distance from the original two days post-ablation, signified by cell proliferation and the expression of CrTAA2. Treatment with the naturally occurring auxin indole-3-acetic acid (IAA), synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D), or the transport inhibitor naphthylphthalamic acid (NPA) altered positioning of the original marginal meristem toward the apex of the gametophyte. IAA altered positioning of the regenerated meristem after damaging the original meristem. A model of auxin involvement in the positioning of the marginal meristem in Ceratopteris is presented to encompass these results.

Laser-Assisted Design of MOF-Derivative Platforms from Nano- to Centimeter Scales for Photonic and Catalytic Applications

Laser conversion of metal-organic frameworks (MOFs) has recently emerged as a fast and low-energy consumptive approach to create scalable MOF derivatives for catalysis, energy, and optics. However, due to the virtually unlimited MOF structures and tunable laser parameters, the results of their interaction are unpredictable and poorly controlled. Here, we experimentally base a general approach to create nano- to centimeter-scale MOF derivatives with the desired nonlinear optical and catalytic properties. Five three- and two-dimensional MOFs, differing in chemical composition, topology, and thermal resistance, have been selected as precursors. Tuning the laser parameters (i.e., pulse duration from fs to ns and repetition rate from kHz to MHz), we switch between ultrafast nonthermal destruction and thermal decomposition of MOFs. We have established that regardless of the chemical composition and MOF topology, the tuning of the laser parameters allows obtaining a series of structurally different derivatives, and the transition from femtosecond to nanosecond laser regimes ensures the scaling of the derivatives from nano- to centimeter scales. Herein, the thermal resistance of MOFs affects the structure and chemical composition of the resulting derivatives. Finally, we outline the "laser parameters versus MOF structure" space, in which one can create the desired and scalable platforms with nonlinear optical properties from photoluminescence to light control and enhanced catalytic activity.

Modeling and in vivo experimental validation of 1,064 nm laser interstitial thermal therapy on brain tissue

Introduction

Laser interstitial thermal therapy (LITT) at 1064 nm is widely used to treat epilepsy and brain tumors; however, no numerical model exists that can predict the ablation region with careful in vivo validation.

Methods

In this study, we proposed a model with a system of finite element methods simulating heat transfer inside the brain tissue, radiative transfer from the applicator into the brain tissue, and a model for tissue damage.

Results

To speed up the computation for practical applications, we also validated P1-approximation as an efficient and fast method for calculating radiative transfer by comparing it with Monte Carlo simulation. Finally, we validated the proposed numerical model in vivo on six healthy canines and eight human patients with epilepsy and found strong agreement between the predicted temperature profile and ablation area and the magnetic resonance imaging-measured results.

Discussion

Our results demonstrate the feasibility and reliability of the model in predicting the ablation area of 1,064 nm LITT, which is important for presurgical planning when using LITT.

Er:YAG laser combined with botulinum toxin A for patients with local syringomas: A preliminary report

Syringoma is a common but refractory benign skin tumor. Conventional treatment, such as ultra-pulsed carbon dioxide (CO2 ) laser or cryotherapy, often requires multiple treatment and can easily cause prolonged erythema, scarring, or depression, which are frustrating, so there is an urgent need to seek a safer and more effective method. In this article, we tried to demonstrate the Er:YAG laser combined with botulinum toxin A (BTXA) as a safer and more efficacious method for treating syringomas.

MATERIALS AND METHODS

Twenty-one patients with local syringomas were treated with erbium laser ablation. Immediately after laser treatment, approximately 10 units of BTXA were sprayed on the wound for 10 min.

RESULT

In total, 21 patients underwent 1.62 ± 0.74 treatments; their Periorbital Syringoma Severity Index (PSSI) score declined from 4.19 (before treatment) to 1.10 (after treatment), and the number of treatments was significantly lower than those reported in previous literature using the erbium laser alone.

CONCLUSION

The Er:YAG laser combined with botulinum toxin A for the treatment of syringoma is a safer and more effective treatment than traditional treatment methods.

Intraventricular SEEG and laser ablation for the treatment of infantile spasm: Technical note

OBJECTIVES

Infantile spasm (IS) is an epileptic encephalopathy with ongoing neurological damage due to seizures and epileptiform abnormalities. Epilepsy surgery is considered for children refractory to drug therapy, especially when there is a focal brain lesion. In this study, we investigated the feasibility and efficacy of intraventricular stereotactic electroencephalography (SEEG) and laser ablation for the treatment of IS children with focal brain lesions.

METHODS

We performed the first reported study using ventriculoscopic laser ablation to treat IS. Seven IS children with drug-resistant epilepsy and definite encephalomalacia on brain magnetic resonance imaging scan were included in this study. Ablation was performed after confirmation of epileptiform discharges by SEEG under the surveillance of ventriculoscope.

RESULTS

The median follow-up time for the cohort was 3.1 years and 86% (6/7) of the children had an Engel class ≤III epilepsy at the final follow-up. Five (71%) children had a reduction in seizure medication usage, and the other two were on the same amount as preablation. None of the children experienced serious new neurological deficits. Laser ablation might result in seizure freedom by destroying the local brain network and blocking the spread of abnormal discharges.

CONCLUSIONS

Intraventricular SEEG and laser ablation was feasible and effective for the treatment of IS. Further studies are warranted.

Penile-Sparing Surgery for Tumour Recurrence after Previous Glansectomy/Partial Penectomy: Treatment Feasibility and Oncological Outcomes

We tested the feasibility and oncological outcomes after penile-sparing surgery (PSS) for local recurrent penile cancer after a previous glansectomy/partial penectomy. We retrospectively analysed 13 patients (1997-2022) with local recurrence of penile cancer after a previous glansectomy or partial penectomy. All patients underwent PSS: circumcision, excision, or laser ablation. First, technical feasibility, treatment setting, and complications (Clavien-Dindo) were recorded. Second, Kaplan-Meier plots depicted overall and local recurrences over time. Overall, 11 (84.5%) vs. 2 (15.5%) patients were previously treated with glansectomy vs. partial penectomy. The median (IQR) time to disease recurrence was 56 (13-88) months. Six (46%) vs. two (15.5%) vs. five (38.5%) patients were treated with, respectively, local excision vs. local excision + circumcision vs. laser ablation. All procedures, except one, were performed in an outpatient setting. Only one Clavien-Dindo 2 complication was recorded. The median follow-up time was 41 months. Overall, three (23%) vs. four (30.5%) patients experienced local vs. overall recurrence, respectively. All local recurrences were safely treated with salvage surgery. In conclusion, we reported the results of a preliminary analysis testing safety, feasibility, and early oncological outcomes of PSS procedures for patients with local recurrence after previous glansectomy or partial penectomy. Stronger oncological outcomes should be tested in other series to optimise patient selection.

A tutorial: Laserspray ionization and related laser-based ionization methods for use in mass spectrometry

This Tutorial is to provide a summary of parameters useful for successful outcomes of laserspray ionization (LSI) and related methods that employ a laser to ablate a matrix:analyte sample to produce highly charged ions. In these methods the purpose of the laser is to transfer matrix-analyte clusters into the gas phase. Ions are hypothesized to be produced by a thermal process where emitted matrix:analyte gas-phase particles/clusters are charged and loss of matrix from the charged particles leads to release of the analyte ions into the gas phase. The thermal energy responsible for the charge-separation process is relatively low and not necessarily supplied by the laser; a heated inlet tube linking atmospheric pressure with the first vacuum stage of a mass spectrometer is sufficient. The inlet becomes the "ion source", and inter alia, pressure, temperature, and the matrix, which can be a solid, liquid, or combinations, become critical parameters. Injecting matrix:analyte into a heated inlet tube using laser ablation, a shockwave, or simply tapping, all produce the similar mass spectra. Applications are provided that showcase new opportunities in the field of mass spectrometry.

The Effect of Cooling Fluid Composition on Ablation Size in Hepatic Laser Ablation: A Comparative Study in an Ex Vivo Bovine Setting

PURPOSE

Hyperthermic ablation is a minimally invasive mode of tumour therapy which serves as a viable alternative to surgical intervention. However, one of the major drawbacks, besides the heat sink effect and the risk of damaging adjacent organs, is limited ablation size. The use of a cooling fluid during ablation has been shown to increase the ablation volume and decrease the carbonisation rate. The aim of this study was to investigate whether the composition of the cooling fluid has an effect on ablation size and carbonisation rate during hepatic laser ablation in an ex vivo bovine setting.

METHOD

In this study bovine hepatic tissue was ablated in an ex vivo setting using an internally cooled laser applicator. A total of 45 tissue samples were assigned to three groups: 0.9% saline infusion (n = 15), distilled water infusion (n = 15) and a 50%/50% mixture of 0.9% saline and distilled water (n = 15). Ablation was conducted using a 1064 nm Nd:YAG laser at a wattage of 25 W and time interval of 10 min. The ablation volume and carbonisation rate were then measured and recorded through postprocedural MRI. One-way ANOVA and post-hoc testing were performed to assess the effect of the cooling fluid composition on the ablation volumes.

RESULTS

We found that using a mixture of saline and distilled water as a cooling fluid during hyperthermic ablation resulted in a larger ablation volume (mean ± SD: 22.64 ± 0.99 cm3) when compared to saline infusion (21.08 ± 1.11 cm3) or distilled water infusion (20.92 ± 0.92 cm3). This difference was highly significant (p < 0.001). There was no significant difference in ablation size between the saline group and the distilled water group. The highest carbonisation rate occurred in the saline group (12/15), followed by the mixed infusion group (3/15) and the distilled water group (1/15).

CONCLUSIONS

The results of this study suggest that cooling fluid composition during hepatic laser ablation affects ablation volume in an ex vivo bovine setting. There was no statistically significant difference when comparing ablation volumes during saline infusion and distilled water infusion, but the carbonisation rate was significantly higher when using saline. The combination of saline and distilled water in a 50%/50% mixture as cooling fluid appears to be an auspicious alternative, as ablation volumes created with it are larger when compared to saline and distilled water alone, while carbonisation rate remains low. This might improve patient outcome as well as patient eligibility for hyperthermic ablation.

Effectiveness and Safety of Percutaneous Treatment in Lesions Suggestive of Thyroid Cancer (Bethesda V and VI-T1aN0M0) Compared to Surgical Treatment: Systematic Review and Meta-Analysis

INTRODUCTION

Thyroid nodules are common entities, with 5% malignancy. Differentiated thyroid cancer represents 90% of thyroid malignancies, with papillary carcinoma being the most common. Management is generally surgical; among its complications are injury to the recurrent laryngeal and superior laryngeal nerve, causing hoarseness, postsurgical hypoparathyroidism, hypothyroidism, and pain. Other noninvasive percutaneous interventions of thermal ablation such as microwave, radiofrequency, or laser incur lower costs and could be an option for treatment.

OBJECTIVE

To determine the effectiveness and safety of thermal ablation in lesions suspected of thyroid cancer (Bethesda V and VI/T1aN0M0) compared to surgical treatment.

METHODS

Systematic review/meta-analysis of observational studies and clinical trials. Database search includes MEDLINE/PUBMED, Embase, Scopus, Scielo, and BVS/LILACS. Studies on patients over 18 years of age with lesions suspicious of thyroid cancer were included.

RESULTS

A total of 10 studies were obtained, with 2939 patients: 1468 subjected to thermal ablation and 1471 to surgery. Regarding effectiveness, no differences were found in local recurrence [relative risk (RR) 1.17 (95% CI 0.69-1.99)] and cervical lymph node metastasis [RR 0.76 (95% CI 0.43-1.36)]. Regarding safety, infection [RR 0.29 (95% CI 0.05-1.74)], hematoma [RR 0.57 (95% CI 0.17-1.94)], and transient hoarseness [RR 0.77 (95% CI 0.39-1.51)] were evaluated, without difference. However, permanent hoarseness had significant differences in favor of thermal ablation [RR 0.29 (95% CI 0.11-0.75)].

CONCLUSIONS

Thermal ablation for the treatment of T1aN0M0 papillary thyroid carcinoma is equally effective when compared to surgical techniques and offers a better safety profile, particularly in permanent hoarseness.

Surface Treatments for Enhancing the Bonding Strength of Aluminum Alloy Joints

Aluminum alloy adhesive bonding joint widely appears in many industrial products. Improving the mechanical performances of aluminum alloy bonding joints has been attracting much effort. To acquire more excellent bonding strength, this paper focused on the effects of different surface treatments, including laser ablation and milling superposed by phosphoric acid anodizing (PAA). The treated surfaces were characterized by roughness and contact angle, and the effects of the geometric parameters of microstructures on wettability, failure mode, and shear strength were examined. The results indicate that those surfaces where the spacing is smaller than the diameter present a hydrophilic property and the corresponding specimens are mainly subject to cohesive failure, and vice versa. Additionally, laser ablation with a properly designed dimple pattern can greatly improve the bonding strength, and the maximum average shear strength of specimens with a thickness of 50 μm reaches 32.82 MPa, which is an increase of 28.15% compared with the original milling specimen. Moreover, fabricating groove or grid patterns on the surfaces and applying PAA treatment can also significantly enhance the bonding strength, reaching up to 36.28 MPa.

Laser Light as an Emerging Method for Sustainable Food Processing, Packaging, and Testing

In this review article, we systematically investigated the diverse applications of laser technology within the sphere of food processing, encompassing techniques such as laser ablation, microbial inactivation, state-of-the-art food packaging, and non-destructive testing. With a detailed exploration, we assess the utility of laser ablation for the removal of surface contaminants from foodstuffs, while also noting the potential financial and safety implications of its implementation on an industrial scale. Microbial inactivation by laser shows promise for reducing the microbial load on food surfaces, although concerns have been raised about potential damage to the physio-characteristics of some fruits. Laser-based packaging techniques, such as laser perforation and laser transmission welding, offer eco-friendly alternatives to traditional packaging methods and can extend the shelf life of perishable goods. Despite the limitations, laser technology shows great promise in the food industry and has the potential to revolutionize food processing, packaging, and testing. Future research needs to focus on optimizing laser equipment, addressing limitations, and developing mathematical models to enhance the technology's uses.

Minimally Invasive Treatments of Benign Thyroid Nodules: A Network Meta-Analysis of Short-Term Outcomes

Background: Image-guided thermal ablation interventions are novel thermal-based modalities used for the treatment of benign thyroid nodules. Methods: We conducted a systematic review and a Bayesian network meta-analysis, examining studies using thermal ablation interventions in the treatment of benign nodular thyroid disease (PROSPERO CRD42022367680). The primary endpoints included volume reduction rate (VRR), and symptomatic score and cosmetic score improvement. Secondary endpoints included vocal disturbances, laryngeal nerve palsy, hypothyroidism, and nodular regrowth (defined by increased nodular volume of >50% for thermal ablation or new nodules arising in remaining thyroid tissue conventional surgery [CS]). Results: We included 16 studies (3 randomized controlled trials [RCTs] and 13 comparative case series), describing radiofrequency ablation (RFA), laser ablation (LA), microwave ablation (MWA), high-intensity focus ultrasound (HIFU), and CS, respectively. The review included data from 4112 patients followed for a mean of 11.9 months. Meta-analyses showed no significant differences among RFA, LA, MWA, HIFU, and CS regarding any of the primary endpoints of VRR, symptomatic score, and cosmetic score. In examining the surface under the cumulative ranking area (SUCRA) ranking, CS (SUCRA, 98.49), LA (SUCRA, 51.58), and MWA (SUCRA, 57.0) were identified as the three interventions that were most likely to result in the largest VRR, symptomatic and cosmetic score reduction. RFA, relative risk (RR) 0.19 [95% credibility interval (CI): 0.06 to 0.48], LA RR 0.23 [CI: 0.06 to 0.79], and MWA RR 0.25 [CI: 0.09 to 0.60] were associated with the greatest reduction in risk for postintervention vocal complications compared with CS, with RFA (SUCRA, 61.62) being ranked as the highest in safety. RFA RR 0.05 [CI: 0.00 to 0.40] and MWA RR 0.16 [CI: 0.02 to 0.73] were associated with a reduced risk of transient laryngeal nerve injury compared with CS. RFA RR 0.00 [CI: 0.00 to 0.00] and MWA RR 0.00 [CI: 0.00 to 0.03] were associated with a reduced risk of hypothyroidism occurrence compared with CS, with RFA (SUCRA, 99.86) yielding the highest safety ranking. RFA was associated with a reduced risk for nodular regrowth RR 0.09 [CI: 0.00 to 0.85], compared with CS. Conclusion: We have comprehensively reviewed the published literature on the efficacy and safety of thermal ablation modalities for benign thyroid nodules. Important research gaps remain regarding a paucity of both long-term data and high-quality RCTs.

Learning from the past and present to change the future: Endoscopic management of upper urinary tract urothelial carcinoma

Current guidelines recommend endoscopic management (EM) for patients with low-risk upper urinary tract urothelial carcinoma, as well as those with an imperative indication. However, regardless of the tumor risk, radical nephroureterectomy is still mainly performed worldwide despite the benefits of EM, such as renal function maintenance, no hemodialysis requirement, and treatment cost reduction. This might be explained by the association of EM with a high risk of local recurrence and progression. Furthermore, the need for rigorous patient selection and close surveillance following EM may be relevant. Nevertheless, recent developments in diagnostic modalities, pathological evaluation, surgical devices and techniques, and intracavitary regimens have been reported, which may contribute to improved risk stratification and treatments with superior oncological outcomes. In this review, considering recent advances in endourology and oncology, we propose novel treatment strategies for optimal EM.

Photodetection Properties of CdS/Si Heterojunction Prepared by Pulsed Laser Ablation in DMSO Solution for Optoelectronic Application

The high-quality n-type CdS on a p-type Si (111) photodetector device was prepared for the first time by a one-pot method based on an ns laser ablation method in a liquid medium. Cadmium target was ablated in DMSO solution, containing sulfur precursor, and stirred, assisting in 1D-growth, to create the sulfide structure as CdS nano-ropes form, followed by depositing on the Si-substrate by spin coating. The morphological, structural, and optical characteristics of the CdS structure were examined using X-ray diffraction, transmission, and scanning electron microscopy, photoluminescence, and UV-VIS spectroscopy. From X-ray diffraction analysis, the growing CdS spheres have a good crystal nature, with a high purity and desired c-axis orientation along the (002) plane, and the crystallinity was around 30 nm. According to optical characterization, high transparency was found in the visible-near-infrared areas of the electromagnetic spectrum, and the CdS spheres have a direct optical energy band gap of 3.2 eV. After that, the CdS/Si hetero-structured device was found to be improved remarkably after adding CdS. It showed that the forward current is constantly linear, while the dark current is around 4.5 µA. Up to a bias voltage of 4 V, there was no breakdown, and the reverse current of the heterojunctions somewhat increased with reverse bias voltage, while the photocurrent reached up to 580 and 690 µA for using 15 and 30 W/cm2 light power, respectively. Additionally, the ideal factors for CdS/Si heterojunction were 3.1 and 3.3 for 15 and 30 W/cm2 light power, respectively. These results exhibited high performance compared to the same heterojunction produced by other techniques. In addition, this opens the route for obtaining more enhancements of these values based on the changing use of sulfide structures in the heterojunction formation.

Laser Ablation-Generated Crystalline Selenium Nanoparticles Prevent Damage of DNA and Proteins Induced by Reactive Oxygen Species and Protect Mice against Injuries Caused by Radiation-Induced Oxidative Stress

With the help of laser ablation, a technology for obtaining nanosized crystalline selenium particles (SeNPs) has been created. The SeNPs do not exhibit significant toxic properties, in contrast to molecular selenium compounds. The administration of SeNPs can significantly increase the viabilities of SH-SY5Y and PCMF cells after radiation exposure. The introduction of such nanoparticles into the animal body protects proteins and DNA from radiation-induced damage. The number of chromosomal breaks and oxidized proteins decreases in irradiated mice treated with SeNPs. Using hematological tests, it was found that a decrease in radiation-induced leukopenia and thrombocytopenia is observed when selenium nanoparticles are injected into mice before exposure to ionizing radiation. The administration of SeNPs to animals 5 h before radiation exposure in sublethal and lethal doses significantly increases their survival rate. The modification dose factor for animal survival was 1.2. It has been shown that the introduction of selenium nanoparticles significantly normalizes gene expression in the cells of the red bone marrow of mice after exposure to ionizing radiation. Thus, it has been demonstrated that SeNPs are a new gene-protective and radioprotective agent that can significantly reduce the harmful effects of ionizing radiation.

Anticancer Activity of Au/CNT Nanocomposite Fabricated by Nanosecond Pulsed Laser Ablation Method on Colon and Cervical Cancer

Gold nanoparticles (AuNPs) and carbon nanotubes (CNTs) are increasingly being investigated for cancer management due to their physicochemical properties, low toxicity, and biocompatibility. This study used an eco-friendly technique (laser synthesis) to fabricate AuNP and Au/CNT nanocomposites. AuNPs, Au/CNTs, and CNTs were tested as potential cancer nanotherapeutics on colorectal carcinoma cells (HCT-116) and cervical cancer cells (HeLa) using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. In addition, the non-cancer embryonic kidney cells HEK-293 were taken as a control in the study. The cell viability assay demonstrated a significant reduction in cancer cell population post 48 h treatments of AuNPs, and Au/CNTs. The average cell viabilities of AuNPs, Au/CNTs, and CNTs for HCT-116 cells were 50.62%, 65.88%, 93.55%, and for HeLa cells, the cell viabilities were 50.88%, 66.51%, 91.73%. The cell viabilities for HEK-293 were 50.44%, 65.80%, 93.20%. Both AuNPs and Au/CNTs showed higher cell toxicity and cell death compared with CNT nanomaterials. The treatment of AuNPs and Au/CNTs showed strong inhibitory action on HCT-116 and HeLa cells. However, the treatment of CNTs did not significantly decrease HCT-116 and HeLa cells, and there was only a minor decrease. The treatment of AuNPs, and Au/CNTs, on normal HEK-293 cells also showed a significant decrease in cell viability, but the treatment of CNTs did not produce a significant decrease in the HEK-293 cells. This study shows that a simplified synthesis technique like laser synthesis for the preparation of high-purity nanomaterials has good efficacy for possible future cancer therapy with minimal toxicity.

Laser Micropatterning Promotes Rete Ridge Formation and Enhanced Engineered Skin Strength without Increased Inflammation

Rete ridges play multiple important roles in native skin tissue function, including enhancing skin strength, but they are largely absent from engineered tissue models and skin substitutes. Laser micropatterning of fibroblast-containing dermal templates prior to seeding of keratinocytes was shown to facilitate rete ridge development in engineered skin (ES) both in vitro and in vivo. However, it is unknown whether rete ridge development results exclusively from the microarchitectural features formed by ablative processing or whether laser treatment causes an inflammatory response that contributes to rete ridge formation. In this study, laser-micropatterned and non-laser- treated ES grafts were developed and assessed during culture and for four weeks post grafting onto full-thickness wounds in immunodeficient mice. Decreases in inflammatory cytokine secretion were initially observed in vitro in laser-treated grafts compared to non-treated controls, although cytokine levels were similar in both groups five days after laser treatment. Post grafting, rete ridge-containing ES showed a significant increase in vascularization at week 2, and in collagen deposition and biomechanics at weeks 2 and 4, compared with controls. No differences in inflammatory cytokine expression after grafting were observed between groups. The results suggest that laser micropatterning of ES to create rete ridges improves the mechanical properties of healed skin grafts without increasing inflammation.

BioQuant: Data Processing Software for Simultaneous Imaging Analysis for Elements and Molecules Using Two Mass Spectrometers

Simultaneous imaging analysis for both elements and molecules was conducted by introducing laser-induced sample particles into two separate mass spectrometers (i.e., an inorganic spectrometer and an organic mass spectrometer) through the split-flow protocol. The timing of ion detections for elements and molecules can be different, reflecting the differences in mass scan rates, lengths for transport tubing, and flow rates of carrier gases, and thus, the timing of ion detections must be carefully aligned to discuss abundance correlations between elements and molecules. To achieve this, a new data processing software "BioQuant" was developed to correct the time difference of the signal intensities for components obtained by the two mass spectrometers. With the BioQuant software, signal intensity data obtained from several unit cells were merged into a newly defined unit cell, calculated by the common time intervals from both mass spectrometers. With the newly defined unit cells, correlation analysis between the elements and molecules can be conducted. Combination of the BioQuant software and laser ablation system connected to two separated mass spectrometers can become a benchmark technique for simultaneous imaging analysis for both the elements and molecules from single sample material.

Rubber-like elasticity in laser-driven free surface flow of a Newtonian fluid

The energy needed to deform an elastic solid may be recovered, while in Newtonian fluids, like water and glycerol, deformation energy dissipates on timescales of the intermolecular relaxation time [Formula: see text] . For times considerably longer than [Formula: see text] the existence of shear elasticity requires long-range correlations, which challenge our understanding of the liquid state. We investigated laser-driven free surface bubbles in liquid glycerol by analyzing their expansion and bursting dynamics, in which we found a flow-dominating, rubber-like elasticity unrelated to surface tension forces. In extension to findings of a measurable liquid elasticity at even very low deformation frequencies [L. Noirez, P. Baroni, J. Mol. Struct. 972, 16-21 (2010), A. Zaccone, K. Trachenko, Proc. Natl. Acad. Sci. U.S.A. 117, 19653-19655 (2020)], that is difficult to access under increased strain, we find a robust, strain rate driven elasticity. The recovery of deformation energy allows the bursting bubble to reach Taylor-Culick velocities 20-fold higher than expected. The elasticity is persistent for microseconds, hence four orders of magnitude longer than [Formula: see text] . The dynamic shows that this persistence cannot originate from the far tail of a distribution of relaxation times around [Formula: see text] but must appear by frustrating the short molecular dissipation. The longer time should be interpreted as a relaxation of collective modes of metastable groups of molecules. With strain rates of 10⁶ s^-1, we observe a metastable glycerol shell exhibiting a rubber-like solid behavior with similar elasticity values and characteristic tolerance toward large strains, although the molecular interaction is fundamentally different.