Oriented-aptamer encoded magnetic nanosensor with laser-induced fluorescence for ultrasensitive test of okadaic acid.

Okadaic acid (OA) biotoxin acts a well-established inhibitor of protein phosphatase even a tumor promoter of human being, arouse great attention in safety monitoring. However, the powerful and convenient nanosensing technologies for addressing the demands such as rapidity, high sensitivity, and stability in the in-field test of OA shellfish toxin is still scarce. Herein, a high-performance magnetic biometric nanosensor (MBNS) integrating oriented aptamers and ultrasensitive laser-induced fluorescence (LIF) was firstly proposed for the in-field detection of trace OA in seafoods. High-density aptamers hybridized with FAM-labeled cDNA were tethered to the surface of AuNPs on magnetic MIL-101@Fe3O4, and then finely regulated by mercaptohexyl alcohol (MCH) to be orderly assembled, as was successfully utilized to engineer an active biological nanosensor for highly specific recognition of OA. Aptamers anchored on magnetic Fe3O4@MOF@AuNPs activate a biometric microreactor of OA, in which the superior LIF properties, conformation regulation of aptamer, and the specific recognition using aptamer genes were adopted. The magnetic nanosensor with an excellent specificity and super sensitivity for OA analysis was achieved within 20 min. Moreover, the content of captured OA could facilely be recorded by measuring the fluorescence intensity, and the limit of detection (LOD) and limit of quantitation of OA (LOQ) reached 0.015 and 0.050 ng/mL respectively, which was far better than most aptamer-based biometric sensing methods. The feasibility for accurate test of trace OA toxin in the fortified shellfish samples was validated with the recovery yields of 88.2-107.5% and RSD of 0.5-7.6%, respectively. The result demonstrated that the oriented-aptamer encoded MNS had significant practical values in rapid and ultrasensitive detection of OA biotoxin and the related safety applications.

Laser-scribing graphene-based electrochemical biosensing devices for simultaneous detection of multiple cancer biomarkers.

In this study, a graphene electrochemical sensor based on laser graphene polymer material was proposed to induce graphene formation on polyimide substrates via fiber laser. The laser produces stable power and results to achieve the benefits of consistency, conductivity, and flexibility. The electrochemical three-electrodes were manufactured on polyimide to replace the traditional three-electrodes by achieving small size and portability. An electrode activation is the modification of laser-scribed graphene electrodes (LSG) to facilitate the binding of liver cancer sites. The evaluation is performed by differential pulse Voltammetry (DPV) to detect cancer proteins in the phosphate buffer saline (PBS) buffer and serum. In a serum environment, the concentrations of alpha-fetoprotein (AFP) and Carcinoembryonic antigen (CEA) were detected from 0.75 ng ml-1 to 100 ng ml-1, AFP and CEA electrodes have a good linear range (R2 = 0.96 and R2 = 0.98), indicating the sensor's sensitivity and specificity for cancer detection. In addition, two types of carcinogenic proteins were monitored in the PBS and successfully detected in this experiment. Based on the results, the appropriate LSG sensor may be used for monitoring with limited resources. Electrode manufacturing is simple, fast, low-cost, small in size, convenient to carry, stable, instant detection, and flexible.

Conceptos actuales en cirugía histeroscópica: superando barreras y ampliando límites / Current concepts in hysteroscopic surgery: Overcoming barriers by extending limits

Dentro de la patología intracavitaria estructural, los miomas submucosos plantean una mayor dificultad de manejo frente a los pólipos. Dentro de los miomas submucosos los miomas tipo0 y1 son más fáciles de tratar, dado que su separación del miometrio subyacente es técnicamente más fácil. Así, las cirugías histeroscópicas más complicadas son actualmente las miomectomías de miomas submucosos tipo2.Se ha empezado a describir también el manejo histeroscópico de miomas tipo3 por histeroscopia.Con este artículo planteamos hacer una revisión de los puntos más relevantes para llevar a cabo un tratamiento adecuado de este tipo de miomas, revisando su diagnóstico, las técnicas quirúrgicas, la preparación de la paciente y la forma de evitar complicaciones quirúrgicas.(AU)

Within structural intracavitary pathology, submucosal myomas are more difficult to manage than polyps. Of the submucosal myomas, type0 and type1 are easier to treat because their separation from the underlying myometrium is technically easier. Therefore, the most complicated hysteroscopic surgeries are currently type2 submucosal myomectomies.We have also begun to describe the hysteroscopic management of type3 myomas.With this article we propose to make a review of the most relevant points for the correct treatment of this type of myoma, reviewing its diagnosis, surgical techniques, patient preparation, and how to avoid surgical complications.(AU)

Dissociation process of polyalanine aggregates by free electron laser irradiation.

Polyalanine (polyA) disease-causative proteins with an expansion of alanine repeats can be aggregated. Although curative treatments for polyA diseases have not been explored, the dissociation of polyA aggregates likely reduces the cytotoxicity of polyA. Mid-infrared free electron laser (FEL) successfully dissociated multiple aggregates. However, whether the FEL dissociates polyA aggregates like other aggregates has not been tested. Here, we show that FEL at 6.1 µm experimentally weakened the extent of aggregation of a peptide with 13 alanine repeats (13A), and the irradiated 13A exerted lesser cytotoxicity to neuron-like cells than non-irradiated 13A. Then, we applied molecular dynamics (MD) simulation to follow the dissociation process by FEL. We successfully observed how the intermolecular ß-sheet of polyA aggregates was dissociated and separated into monomers with helix structures upon FEL irradiation. After the dissociation by FEL, water molecules inhibited the reformation of polyA aggregates. We recently verified the same dissociation process using FEL-treated amyloid-ß aggregates. Thus, a common mechanism underlies the dissociation of different protein aggregates that cause different diseases, polyA disease and Alzheimer's disease. However, MD simulation indicated that polyA aggregates are less easily dissociated than amyloid-ß aggregates and require longer laser irradiation due to hydrophobic alanine repeats.

Projection mapping system for laser speckle contrast image: feasibility study for clinical application.

Significance: Laser speckle contrast images (LSCIs) have been utilized to monitor blood flow perfusion. However, they have conventionally been observed on monitor screens, resulting in potential spatial mismatching between the imaging region of interest (IROI) and monitor screen. Aim: This study proposes a projection mapping (PM) system for LSCIs (PMS_LSCI) that projects LSCIs to directly observe the blood flow perfusion in the IROI. Approach: The PMS_LSCI consists of a camera, imaging optics, a laser projector, and graphic user interface software. The spatial matching in the regions of interest was performed by adjusting the software screen of the LSCI in the IROI and evaluated by conducting in-vitro and in-vivo studies. An additional in-vivo study was performed to investigate the feasibility of real-time PM of the LSCI. Results: The spatial mismatching in the regions of interest was ranged from 2.74% to 6.47% depending on the surface curvature. The PMS_LSCI could enable real-time PM of LSCI at four different blood flow states depending on blood pressure. Conclusions: The PMS_LSCI projects the LSCI in the IROI by interacting with a projector instead of the monitor screen. The PMS_LSCI presented clinical feasibility in the in-vitro and in-vivo studies.

Towards phase-sensitive optical coherence tomography in smart laser osteotomy: temperature feedback.

Thermal effects during bone surgery pose a common challenge, whether using mechanical tools or lasers. An irrigation system is a standard solution to cool the tissue and reduce collateral thermal damage. In bone surgery using Er:YAG laser, insufficient irrigation raises the risk of thermal damage, while excessive water lowers ablation efficiency. This study investigated the potential of optical coherence tomography to provide feedback by relating the temperature rise with the photo-thermal expansion of the tissue. A phase-sensitive optical coherence tomography system (central wavelength of λ=1.288 µm, a bandwidth of 60.9 nm and a sweep rate of 104.17 kHz) was integrated with an Er:YAG laser using a custom-made dichromatic mirror. Phase calibration was performed by monitoring the temperature changes (thermal camera) and corresponding cumulative phase changes using the phase-sensitive optical coherence tomography system during laser ablation. In this experiment, we used an Er:YAG laser with 230 mJ per pulse at 10 Hz for ablation. Calibration coefficients were determined by fitting the temperature values to phase later and used to predict the temperature rise for subsequent laser ablations. Following the phase calibration step, we used the acquired values to predict the temperature rise of three different laser-induced cuts with the same parameters of the ablative laser. The average root-mean-square error for the three experiments was measured to be around 4 °C. In addition to single-point prediction, we evaluated this method's performance to predict the tissue's two-dimensional temperature rise during laser osteotomy. The findings suggest that the proposed principle could be used in the future to provide temperature feedback for minimally invasive laser osteotomy.

RNA structures and dynamics with Å resolution revealed by x-ray free-electron lasers.

RNA macromolecules, like proteins, fold to assume shapes that are intimately connected to their broadly recognized biological functions; however, because of their high charge and dynamic nature, RNA structures are far more challenging to determine. We introduce an approach that exploits the high brilliance of x-ray free-electron laser sources to reveal the formation and ready identification of angstrom-scale features in structured and unstructured RNAs. Previously unrecognized structural signatures of RNA secondary and tertiary structures are identified through wide-angle solution scattering experiments. With millisecond time resolution, we observe an RNA fold from a dynamically varying single strand through a base-paired intermediate to assume a triple-helix conformation. While the backbone orchestrates the folding, the final structure is locked in by base stacking. This method may help to rapidly characterize and identify structural elements in nucleic acids in both equilibrium and time-resolved experiments.

Efficacy of laser in re-osseointegration of dental implants-a systematic review.

Despite their high success rates, peri-implantitis can affect the stability and function of dental implants. Various treatment modalities have been investigated for the treatment of peri-implantitis to achieve re-osseointegration. An electronic literature search was performed supplemented by a manual search to identify studies published until January 2022. Articles that evaluated re-osseointegration in peri-implantitis sites in animal models following laser therapy or antimicrobial photodynamic therapy (aPDT) were included. Case reports, case series, systematic reviews, and letters to the editor were excluded. Risk of bias and GRADE assessment were followed to evaluate the quality of the evidence. Six studies out of 26 articles identified on electronic search were included in this review. The studies included animal studies conducted on canine models. Four out of six studies reported a higher degree of re-osseointegration following treatment of implants with laser therapy. The findings suggest that laser decontamination shows potential in enhancing re-osseointegration, particularly with the Er: YAG laser, which effectively decontaminated implant surfaces. However, conflicting outcomes and limitations in the evidence quality warrant caution in drawing definitive conclusions. Based on the limited available evidence, laser therapy may show a higher degree of re-osseointegration of implants than mechanical debridement.

Improving mass accuracy in matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of pathogenic proteins using 6xHIS-tagged internal calibration.

RATIONALE: Linear mode of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) has been routinely used for bacterial identification in the clinic, depending on the pattern analysis of spectral libraries rather than accurate mass measurement of ribosomal proteins (10-15 kDa). However, a demand for more accurate mass analysis of pathogens (e.g. KPC-2 carbapenemase) has been recently increasing for diagnostic purposes. METHODS: We introduced a 6xHIS-tagged KPC-2 (i.e. hKPC-2) and used it as an internal mass calibrator for the mass calibration of target proteins. After internal mass calibration (In-Cal), we evaluated the observed mass of KPC-2 against the theoretical mass of hKPC-2, which has 823 Da mass difference from the target protein. We further assessed the accuracy and precision of our calibration method regarding the identification of KPC-2 and other pathogens in clinical isolates (n = 42). RESULTS: Among several candidates for internal mass calibrators, the In-Cal using a 6xHIS-tagged protein on the target showed the highest mass accuracy and precision in the detection of target proteins (e.g. KPC-2). The application of hKPC-2 as an internal calibrator showed substantial improvement of mass accuracy, mass precision and also quantification of KPC in linearity and repeatability for KPC detection in the clinical isolates. CONCLUSIONS: Our In-Cal method using 6xHIS-tagged protein in MALDI-TOFMS allows successful mass calibration (<3.5 Da) of pathogenic proteins (>20 kDa) and provides high mass accuracy as much as that of medium- and high-resolution mass spectrometry.

Influence of age on voice quality after transoral CO2 laser microsurgery.

OBJECTIVE: To study the post-operative evolution of voice quality of patients treated by transoral CO2 laser microsurgery (TLM) according to the age. METHODS: Patients treated by type I to VI TLM and post-operative speech therapy were prospectively recruited from our hospital. The voice quality was assessed pre-, 1-, 3- 6- and 12-month posttreatment with voice handicap index (VHI), dysphonia, roughness, breathiness, asthenia, strain (GRBAS), maximal phonation time (MPT), F0, F0 standard deviation (STD), percent jitter, percent shimmer, noise-to-harmonic ratio (NHR), vocal fold vibration assessment and speech fluency. Evolution of voice outcomes was analyzed considering age of patients (< 60 vs. ≥ 60 years). RESULTS: Seventy-five patients completed the evaluations. Thirty-four and forty-one patients were < 60 or ≥ 60 yo, respectively. Subjective and objective voice parameters (VHI, G, R, B), jitter and fluency significantly improved from 1- to 6-month post-TLM in < 60 yo individuals. The voice parameters improved 12-month post-TLM in the ≥ 60 yo group at the exception of VHI that improved 3-month post-TLM. There were positive associations between age and 12-month NHR, G and A parameters. CONCLUSION: The post-operative evolution of voice quality parameters may vary between patients according to the age. Preoperative VHI is predictive of 12-month subjective and objective voice outcomes.

Infrared pulsed fiber laser-produced gold and silver-109 nanoparticles for laser desorption/ionization mass spectrometry of steroid hormones.

RATIONALE: Hormones are compounds that perform many important functions in the human body, but above all their task is to maintain homeostasis by adapting them to the constantly changing environmental conditions. Even minor hormonal disorders have a negative effect on the body, leading to physical or mental changes. Therefore, monitoring these changes and precise quantification of hormones are essential for the early diagnosis of diseases related to hormonal disorders. METHODS: Application of monoisotopic silver-109 and gold nanoparticles obtained by PFL (pulsed fiber laser) 2D GS (galvo-scanner) LGN (laser-generated nanomaterial) for high-resolution laser desorption/ionization mass spectrometry (LDI-MS) and mass spectrometry imaging (MSI) of steroid hormones is presented. Four steroid hormones, estrone, prednisolone, corticosterone and progesterone, were used as test compounds for quantitative analysis with matrix-assisted LDI time-of-flight MS apparatus. Moreover, comparison of manual measurements and semiautomatic MSI with both types of nanoparticles was performed. Methods were also tested on spiked human blood serum for quantification of steroid hormones and for estimation of the matrix effect. RESULTS: Hormones were directly tested in 1 000 000-fold concentration change conditions ranging from 1 mg/mL to 1 ng/mL which equates to 300 ng to 300 fg of hormone per measurement spot. For almost all tested hormones MSI allowed one to obtain equal or lower limit of detection value than manual LDI-MS. The best results judged by lowest limit of detection values are found for silver-109 nanoparticles. CONCLUSION: The results of the quantitative analysis of steroid hormones using silver-109 and gold nanoparticles prepared with PFL 2D GS LGN for LDI-MS and semiautomatic LDI-MSI are presented. It has been proven that nanoparticles obtained by laser synthesis can be successfully used for the analysis of steroid hormones in a wide range of concentrations.

Subthreshold Micropulse Laser Acute Exudative Maculopathy in Central Serous Chorioretinopathy.

Photodynamic acute exudative maculopathy is a transient increase in subretinal fluid (SRF) within the first days after treatment in different chorioretinal diseases and tumors. Recently, this entity has attracted much attention. However, no cases of acute exudative maculopathy have been described after subthreshold laser (STL). This report presents the case of a 35-year-old male with chronic central serous chorioretinopathy with an extrafoveal serous retinal pigment epithelium detachment (PED) who underwent STL. One day after treatment, the patient noted an acute decrease in visual acuity and abundant SRF. One month after treatment, both the SRF and PED were spontaneously resolved. [Ophthalmic Surg Lasers Imaging Retina 2023;54:540-542.].

Proof of concept of intracochlear drug administration by laser-assisted bioprinting in mice.

Transtympanic administration is used clinically for the injection of gentamicin and/or corticosteroids. This atraumatic route is based on passive diffusion through the round window membrane (RWM). The main limitation of this method is related to the clearance through the Eustachian tube, making the concentration of the therapeutic agent at the intracochlear level uncertain and limited. Moreover, this technique remains unsuitable for molecules of high molecular weight or in the case of gene therapies. The purpose was to study a new technique of intracochlear administration in an atraumatic, direct and controlled manner by laser-assisted bioprinting (LAB). LAB was used to deliver dexamethasone phosphate with thermosensitive hydrogel on the mouse RWM. After validation of the regularity and homogeneity of the pattern, the diffusion in vivo of the dexamethasone into the perilymph after LAB has been confirmed by ELISA. Auditory function measurements showed no hearing impairment suggesting that bioprinting does not induce significant cochlear damage. Hence, the present proof of concept study introduces a promising approach for inner ear drug delivery.

Body Boundary Measurement Using Multiple Line Lasers for a Focused Microwave Thermotherapy System: A Proof-of-Concept Study.

A focused microwave thermotherapy system for non-invasively treating cancerous tumors has recently been actively developed. To accurately focus on the target location, the system needs information about the patient's body boundary. However, a water bolus is placed between the human body and the microwave applicators to allow the microwave to penetrate the body more easily and cool the body's skin. The structural configuration makes it difficult to measure the body boundary. In this paper, we present a body boundary measurement method using multiple line lasers and cameras for the application of a focused microwave thermotherapy system. Even with a lack of acquired boundary data, a completely closed boundary line can be reconstructed. In addition, real-time movement tracking is possible as it can be measured quickly, even in situations where the patient is moving, such as breathing and wriggling. The performance is verified with several indicators in a water-filled experimental testbed.

Changes in Corneal Biomechanical Properties after Laser-Assisted in situ Keratomileusis and Photorefractive Keratectomy in Myopia.

OBJECTIVE: To compare changes in corneal biomechanical properties after laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in low and moderate myopia by Ocular Response Analyzer. STUDY DESIGN: Quasi-experimental study. Place and Duration of the Study: Armed Forces Institute of Ophthalmology (AFIO), Rawalpindi, Pakistan, between September 2020 and April 2022. METHODOLOGY: Myopic correction was done in forty-six eyes of twenty-three patients by PRK, and forty-seven eyes of twenty-four patients by LASIK. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using Ocular Response Analyzer (ORA), pre-operatively, and then 1, 3, and 6 months, postoperatively. The relationship between the amount of myopia treated and biomechanical properties was also studied. RESULTS: CRF and CH were decreased significantly after LASIK and PRK. A significantly larger decrease in CRF was observed after LASIK as compared to PRK at 6 months (Mann-Whitney U test: CRF, p = 0.02); however, decrease in CH was not statistically significant between LASIK and PRK at 6 months period (Mann-Whitney U test: CH, p = 0.388). A significant correlation was observed between the changes in biomechanical properties and extent of myopic correction after LASIK and PRK. CONCLUSION: Biomechanical strength of the cornea was significantly reduced by PRK and LASIK, which was also dependent on the spherical equivalent (SEQ) of myopic correction. A significantly larger change in CRF was observed after LASIK as compared to post PRK. KEY WORDS: Myopia, Laser in situ keratomileusis, Photorefractive keratectomy, Cornea, Biomechanics.

Shelf-life, bioburden, water and oxygen permeability studies of laser welded SEBS/PP blended polymer.

The most common material used for blood bags is PVC, which requires the addition of DEHP to increase its flexibility. DEHP is known to cross the polymer barrier and move into the stored blood and, ultimately, the patient's bloodstream. In this work, an alternative prototype composed of SEBS/PP was fabricated through blow-moulding and compared with the commercially available PVC-based blood bag which was designated as the control. The blow-moulded sample layers were welded together using CO2 lasers and optimized to obtain complete sealing of the sides. The samples' performance characteristics were analyzed using water permeability, oxygen permeability, shelf-life, and bioburden tests. The SEBS/PP sample exhibited the highest oxygen permeability rate of 1486.6 cc/m2/24 h after 40 days of ageing, indicating that the sample is conducive for red blood cell (RBC) respiration. On the other hand, the SEBS/PP sample showcased a lower water permeability rate of 0.098 g/h m2 after 40 days of aging, indicating a high-water barrier property and thus preventing water loss during storage. In comparison, the oxygen and water permeability rates of PVC-DEHP were found to be distinctly lower in performance (662.7 cc/m2/24 h and 0.221 g/h m2, respectively). In addition, shelf-life analyses revealed that after 40 days of ageing, polymer samples exhibited no visual damage or degradation. The optimal parameters to obtain adequate welding of the SEBS/PP were determined to be power of 60% (18 W), speed of 70 in/sec and 500 Pulse Per Inch (PPI). Furthermore, the bioburden estimates of SEBS/PP of 115 CFU are markedly lower compared to the bioburden estimate of PVC-DEHP of 213 CFU. The SEBS/PP prototype can potentially be an effective alternative to PVC-based blood bags, particularly for high-risk patients in order to reduce the likelihood of medical issues.