Successful Laser Research Articles

Lincomycin–embedded PANI–based coatings for biomedical applications

We report on the successful laser transfer of biocompatible composite coatings based on polyaniline (PANI) embedded with magnetite (PANI-Fe3O4) and Lincomycin hydrochloride (PANI-Lincomycin) or Lincomycin-functionalized magnetite (PANI-Fe3O4@Lincomycin) by matrix assisted pulsed laser evaporation (MAPLE) technique.The physico-chemical investigations revealed relevant data regarding the stoichiometric deposition, morphology and topography of the as-deposited coatings. Regarding the MAPLE coatings, the FTIR studies evidenced the vibrational bands characteristic to pristine PANI material, while the SEM investigations unveiled a preferential particulate morphology (with aggregates shape and size depending on the deposited material). Additionally, the AFM measurements indicated variations of RMS value, following the Lincomycin and magnetite incorporation. The wettability measurements displayed a hydrophilic behavior of the synthesized coatings, while the electrochemical studies emphasized an enhanced resistance against corrosion in simulated body fluid when compared with bare Ti.Cellular viability, immunofluorescence and SEM results proved that the MAPLE coatings were suitable materials for beneficial adhesion, spreading and proliferation of osteoblast-like cells (MG-63). Moreover, an increased efficiency was evidenced against Staphylococcus aureus biofilm development.The multifunctional properties of the laser processed composite coatings – confirmed by cumulative biocompatible, antimicrobial and anticorrosive behaviors – recommend them as promising solutions for biomedical applications.

MALDI Matrix Application Utilizing a Modified 3D Printer for Accessible High Resolution Mass Spectrometry Imaging.

Successful matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) relies on the selection of the most appropriate matrix and optimization of the matrix application parameters. In order to achieve reproducible high spatial-resolution imaging data, several commercially available automated matrix application platforms have become available. However, the high cost of these commercial matrix sprayers is restricting access into this emerging research field. Here, we report an automated platform for matrix deposition, employing a converted commercially available 3D printer ($300) and other parts commonly found in an analytical chemistry lab as a low-cost alternative to commercial sprayers. Using printed fluorescent rhodamine B microarrays and employing experimental design, the matrix deposition parameters were optimized to minimize surface analyte diffusion. Finally, the optimized matrix application method was applied to image three-dimensional MCF-7 cell culture spheroid sections (ca. 500 μm diameter tissue samples) and sections of mouse brain. Using this system, we demonstrate robust and reproducible observations of endogenous metabolite and steroid distributions with a high spatial resolution.

Laryngotracheal stenosis in burn patients requiring mechanical ventilation

ObjectiveTo identify the incidence of laryngotracheal stenosis (LTS) in burn patients requiring mechanical ventilation at a regional academic burn center.MethodsA retrospective review of all burn patients requiring endotracheal intubation or tracheostomy for airway management between 2003 and 2009 was performed. A group of trauma patients requiring similar airway instrumentation during the same period of time was used as a control.ResultsNone of the trauma patients and 2 of the burn patients developed LTS. Both presented with stridor and were diagnosed within 2–5 weeks after extubation. One patient underwent successful carbon dioxide laser radial incision and dilation and continues to do well. The other patient failed endoscopic treatment and required T-tube placement. The incidence of LTS in burn patients requiring mechanical ventilation was 2.98% overall and 4.76% among those with inhalational injury.ConclusionsPatients become symptomatic within weeks of the initial injury. Treatment is challenging and multiple surgical procedures are often required. A larger study is necessary to determine if the incidence is higher among burn patients.

Laser Retinotomy with “Ultra Q Reflex” System for the Prevention of Rhegmatogenous Retinal Detachment due to the Peripheral Horseshoe Tears

Purpose. To evaluate laser retinotomy efficacy in the retinal detachment (RD) due horseshoe tear prevention. Patients and methods. 57 eyes of 54 patients with subclinical retinal detachment due to the peripheral horseshoe retinal tear were enrolled. 26 eyes of 25 patients of main group undergone combined laser technology included a barrier retinal photocoagulation of the local detachment zone, accompanied with deffered Nd:YAG laser retinotomy. The barrier retinal photocoagulation alone was performed on 31 eyes of 29 patients in control group to compare postoperation results. The assessment of the peripheral vitreoretinal interface was carried out by fundus ultrasound scanning, multispectral scanning laser imaging and spectral optical coherence tomography. The efficacy of the laser treatment was estimated by local retinal detachment height and area changes, while the safety was estimated by intra- and post-op complications rate. All patients were examined at the baseline, 1 week, 1, 3, 6 and 12 month follow-up. Results. Both main and control groups undergone barrier laser photocoagulation with complete round demarcation of subclinical local retinal detachment. All twenty five patients of main group achieved successful laser resection of retinal horseshore flap without any evidence of clinically significant complications. YAG-laser retinotomy in patients with retinal horseshoe tear resulted in decreased values of local retinal detachment height and area (in 40 and 38% respectively, p < 0.05). At the 12-month follow-up full retinal adhesion has been achieved in 15 eyes (58%), while partial adhesion has been observed in 7 eyes (27%). Obtained data were significantly lower compared with control group where some sings of retinal detachment progression were appeared (in 11 and 4% respectively, p > 0.05). No evidence of clinically significant complications after laser treatment has been revealed. Conclusions. The obtained data have demonstrated the efficacy and the safety of laser retinotomy in traction component reducing and consequent risk of retinal detachment minimising.

Management of twin–twin transfusion syndrome with an extremely short cervix

The objective of this study was to describe the management and perinatal outcomes of patients with twin–twin transfusion syndrome (TTTS) and an extremely short cervical length (CL). This retrospective study examined 17 patients with TTTS and a preoperative CL ≤1.0 cm who had undergone laser surgery and perioperative cervical cerclage placement successfully. In this subset of patients, the median interval between surgery and delivery was 9.6 (range 2.1–13.9) weeks and only one patient had PPROM within 3 weeks of surgery. The median gestational age at delivery was 30.9 (range 23.1–37.6) weeks, 30-day survival of at-least-one twin was 88.2% and dual survivorship was 82.4%. Overall, patients with TTTS and a preoperative CL ≤1.0 cm who were able to undergo successful laser surgery and emergent cerclage placement had favourable outcomes.Impact statementThe management of patients with twin–twin transfusion syndrome (TTTS) and extremely short cervical length (CL) varies between foetal surgery centres.This study demonstrates that laser surgery and cerclage placement in such patients are not only technically feasible, but also can result in favourable perinatal outcomes.Patients with an extremely short CL should not be uniformly excluded from laser surgery for TTTS.

Successful Laser Sintering of Aluminum Oxide

Successful Laser Sintering of Aluminum Oxide

Application value of diode laser in situ fenestration in the thoracic endovascular aortic repair for the treatment of aortic arch disease

Objective To evaluate the application value of diode laser in situ fenestration in the thoracic endovascular aortic repair (TEVAR) for the treatment of aortic arch disease. Methods The retrospective cross-sectional study was conducted. The clinical data of 110 patients with aortic arch disease who underwent TEVAR using diode laser in situ fenestration in the Ninth People′s Hospital of Shanghai Jiaotong University School of Medicine from January 2014 to June 2017 were collected. TEVAR using diode laser in situ fenestration was performed according to the lesion involving the three branches of aortic arch. Observation indicators: (1) surgical and intraoperative situations; (2) follow-up. All patients were followed up by outpatient examination, inpatient examination and telephone interview up to May 2017. CT angiography was performed to evaluate the patency of the stents and presence of endoleak at 3, 6, and 12 months postoperatively. Measurement data with normal distribution were represented as ±s. Results (1) Surgical and intraoperative situations: 106 of 110 patients underwent successful TEVAR using diode laser in situ fenestration. Intraoperative digital subtraction angiography (DSA) showed that primary aortic dissection incisions were completely closed, with a patency of all stents and no fenestration-related endoleaks. The surgical success rate was 96.36% (106/110). Two patients died of intraoperative pericardial tamponade and 2 received chimney stent implantation after complex anatomic configuration of the aortic arch inducing to failure of the innominate artery fenestration. Of 106 patients, 70 received left subclavian arterial fenestration, 30 received 3 aortic branches fenestration and 6 received both left subclavian arterial and left common carotid arterial fenestrations. The operation time and dose of contrast agent in 110 patients were respectively (140±9)minutes and (185±5)mL. Four patients had postoperative complications, 1 died of severe pulmonary infection and 3 with cerebral infarction were improved by anti-platelet, brain nerve nutrition and other symptomatic treatment. Other patients had no transient ischemic attack, stroke, brain infarction, myocardial infarction or other neurological complications. Duration of hospital stay of the 110 patients was (15 ± 7)days. (2) Follow-up: 99 of 107 patients were followed up for 2-17 months, with a median time of 10 months. During the follow-up, there were patencies of all stents, and endoleaks of 4 patients occurred and were closely followed up and observed. Conclusion The diode laser in situ fenestration is safe and feasible in the TEVAR for the treatment of aortic arch disease, with satisfactory short-term outcomes. Key words: Aortic dissection; Aortic aneurysm; Aortic arch; Thoracic endovascular aortic repair; In situ fenestration, diode laser

Renal function in neonates with twin-twin transfusion syndrome treated with or without fetoscopic laser surgery

The aim of this study is to investigate the short-term renal function in neonates with twin-twin transfusion syndrome (TTTS), treated with fetoscopic laser surgery (laser group) or conservatively (non-laser group). Creatinine and urea levels and urine output were recorded in the first week after birth. Primary outcome was short-term renal dysfunction, defined as a creatinine level of >100 μmol/L during the first week postpartum. We evaluated 312 twins (laser group, n = 274; non-laser group, n = 38). Median creatinine and urea levels were lower in the laser group than in the non-laser group (71 versus 82 μmol/L, p = 0.002). Short-term renal dysfunction was lower in the laser group compared to the non-laser group (7.2 versus 34.4%, p < 0.001). Within the laser group, creatinine levels were significantly higher in the subgroup with incomplete laser surgery compared to twins with successful laser surgery (76 versus 69 μmol/L, p = 0.018). No differences were found between donors and recipients except for a higher incidence of oliguria in donors in the non-laser group on day 1.Conclusion: Short-term renal dysfunction occurs less frequently in TTTS twins treated with fetoscopic laser coagulation, particularly after complete surgery, suggesting that laser surgery may have a protective effect on renal function.What is Known:• Antenatally, donor twins in TTTS have severe oliguria due to chronic hypovolemia and impaired renal perfusion• Postnatally, donor twins may suffer from severe renal complications, particularly in TTTS twins treated conservatively.What is New:• The incidence of short-term renal failure in TTTS twins treated with complete laser surgery is low.• After incomplete laser surgery, the incidence of short-term renal dysfunction is increased.

Simulation of longitudinal dynamics of laser-cooled and RF-bunched C3+ ion beams at heavy ion storage ring CSRe**Supported by National Natural Science Foundation of China (11405237, 11504388)

Laser cooling of Li-like C3+ and O4+ relativistic heavy ion beams is planned at the experimental Cooler Storage Ring (CSRe). Recently, a preparatory experiment to test important prerequisites for laser cooling of relativistic 12C3+ ion beams using a pulsed laser system has been performed at the CSRe. Unfortunately, the interaction between the ions and the pulsed laser cannot be detected. In order to study the laser cooling process and find the optimized parameters for future laser cooling experiments, a multi-particle tracking method has been developed to simulate the detailed longitudinal dynamics of laser-cooled ion beams at the CSRe. Simulations of laser cooling of the 12C3+ion beams by scanning the frequency of the RF-buncher or continuous wave (CW) laser wavelength have been performed. The simulation results indicate that ion beams with a large momentum spread could be laser-cooled by the combination of only one CW laser and the RF-buncher, and show the requirements of a successful laser cooling experiment. The optimized parameters for scanning the RF-buncher frequency or laser frequency have been obtained. Furthermore, the heating effects have been estimated for laser cooling at the CSRe. The Schottky noise spectra of longitudinally modulated and laser-cooled ion beams have been simulated to fully explain and anticipate the experimental results. The combination of Schottky spectra from the highly sensitive resonant Schottky pick-up and the simulation methods developed in this paper will be helpful to investigate the longitudinal dynamics of RF-bunched and ultra-cold ion beams in the upcoming laser cooling experiments at the CSRe.

Safety and efficacy of laryngeal mask airway ventilation in obese patients with airway stenosis.

To assess the efficacy of laryngeal mask airway (LMA) ventilation in obese patients with airway stenosis. A retrospective chart review was conducted in an academic practice in a tertiary care center. We retrospectively reviewed our experience using LMA ventilation in obese patients with airway stenosis. Lowest intraoperative O2 saturation and maximum-end tidal carbon dioxide (CO2 ) levels were recorded. Complications including intubation, unplanned admission, re-admission, postoperative pain, dysphonia, oral trauma, pneumothorax, pneumomediastinum, and tracheostomy were recorded. Fourteen bronchoscopies with laser incisions and dilation were performed in patients with airway stenosis exclusively using LMA ventilation. Thirteen of 14 procedures were performed on patients who had body mass index (BMI) > 30 kg/m2 . Mean BMI was noted to be 38 kg/m2 (range 25-54). All patients underwent successful laser incisions and dilation via LMA anesthesia without major or minor adverse events. The mean lowest O2 saturation level was noted to be 92%; the mean highest CO2 level was noted to be 56 mm Hg; and no patients required endotracheal intubation. In this small series of obese patients with airway stenosis, LMA anesthesia was effectively used without major or minor complications. 4. Laryngoscope, 127:2582-2584, 2017.

Microstructural control during laser additive manufacturing of single-crystal nickel-base superalloys: New processing–microstructure maps involving powder feeding

The control of solidification microstructure is critical to successful laser processing of single-crystal (SX) nickel-base superalloys and a practical tool for the microstructural control is processing–microstructure maps. However, the maps presented in literature do not consider the effects of powder feeding during laser additive manufacturing (LAM) of SX superalloys. This paper therefore presents a simple and feasible strategy to deal with the effects of powder feeding and to extend the combined numerical model used to calculate processing–microstructure maps. A characteristic ratio of epitaxial SX growth was defined to quantitatively compare the final solidification microstructure. Resulting processing–microstructure maps can estimate the influence of most processing variables, especially powder feeding rate, on the extent of epitaxial SX growth and the position of columnar-to-equiaxed transition. Using the processing parameters selected according to these processing–microstructure maps, a multi-layer SX deposit with fine dendrites was successfully fabricated by LAM. This successful SX LAM indicates that these new processing–microstructure maps involving powder feeding are reliable and useful because they can determine proper processing windows for LAM of SX superalloys and further advance the understanding of the processing–microstructure relationship in powder-feeding LAM process.

A Diatomic Molecule is One Atom too Few

The successful laser cooling of a triatomic molecule paves the way towards the study of ultracold polyatomic molecules.

Modern flexible ureteroscopy in Cohen cross-trigonal ureteral reimplantations

We describe a feasible flexible ureteroscopy (fURS) technique with the latest instruments to and to discuss their advantages. Three patients underwent a fURS for stone treatment. A 7F angled orifice catheter and a hydrophilic angled tip stiff wire is used to guide the wire in the proper ureteral direction sighting the ureter allowing the use of a 10/12 ureteral access sheath. A single use ureteroscope was used. All of them had successful ureteral access and laser lithotripsy being stone free endoscopically. No complications reported. The modern fURS technique was found feasible and safe in patients with cross-trigonal ureteroneocystostomy.

Enhanced Photoluminescence of Solution-Exfoliated Transition Metal Dichalcogenides by Laser Etching.

Using a conventional Raman experimental apparatus, we demonstrate that the photoluminescent (PL) yield from ultrasonication-exfoliated transition metal dichalcogenides (TMDs) (MoS2 and WS2) can be increased by up to 8-fold by means of a laser etching procedure. This laser etching process allows us to controllably pattern and reduce the number of layers of the solution-exfoliated material, overcoming the key drawback to solvent-based exfoliation of two-dimensional (2D) semiconducting materials for applications in optoelectronics. The successful laser thinning of the exfoliated 2D crystals was investigated systematically by changes in both Raman and PL spectra. A simple proof-of-principle of the scalability of this laser etching technique for solution-exfoliated TMD crystals was also demonstrated. As well as being applicable for individual materials, it is also possible to use this simple laser etching technique to investigate the structure of solution-generated van der Waals heterostructures, consisting of layers of both MoS2 and WS2.

Telangiectasia of the face: risk factors for reappearance in patients treated with dye laser.

Lasers can be successfully used in the treatment of facial telangiectasias. Nevertheless, reappearance of telangiectasias after successful laser treatment is a significant problem. Risk factors involved in the reappearance have not been previously investigated. To evaluate whether personal, clinical and behavioural factors can influence the recurrence or new appearance of telangiectasias after treatment. Four hundred and fifteen women and 69 men obtaining complete clearance after laser treatment were included in the study and the role of different risk factors in the reappearance of telangiectasias was analysed. Immunocompromised patients were excluded. A statistical analysis was then performed. Twenty four percent of women and 14.5% of men enrolled showed a persistent clearance after treatment. In women in whom telangiectasias reappeared, logistic regression highlighted the importance of tanning addiction, aesthetic medicine and surgery procedures as risk factors, while therapy for menopause was found to be a protective factor. Hypertension was found to be a risk factor in men. The efficacy of laser for treatment of telangiectasias of the face has been previously proven. Nevertheless, this is the first study presenting an analysis of risk factors involved in the new appearance of telangiectasias after the clearance induced by therapy.

Predictors of Successful Laser Capsulotomy for Significant Posterior Capsule Opacification after Phacoemulsification.

Purpose:This study aimed to determine the reasons behind the failure of laser capsulotomy (LC) performed for significant posterior capsular opacification (PCO).Methods:Eighty-eight eyes of 88 patients referred for LC at a tertiary care center were retrospectively analyzed. The data recorded included the cause of cataract, visual acuity, duration of PCO, location of PCO, intraocular lens (IOL) position, IOL type, and lens capsule status. These data were later analyzed for determining the requirement of high pulse energy during LC and the success rate of primary LC.Results:The mean age of the participants was 55.77 ± 18.60 years with 58 (65.9%) male patients. The mean duration between cataract and LC surgeries was 45.58 ± 37.33 months. Senile (n=58), uveitic (n=12), post-pars plana vitrectomy (PPV) (n=12), and traumatic (n=6) cataracts were the common causes. Late-presenting PCO, trauma, uveitis, sulcus placement of IOLs, irregular capsulorhexis shape, and polymethyl methacrylate (PMMA) IOLs were significantly associated with unsuccessful LC and/or higher pulse energy settings during LC.Conclusion:Significant PCO is often associated with cataract caused by uveitis or trauma, and after PPV. PCO associated with trauma, sulcus placement of IOLs, and PMMA IOLs may need multiple LCs.

Targeted Ablation Using Laser Nanosurgery.

Laser-mediated dissection methods have been used for many years to micro-irradiate biological samples, but recent technological progress has rendered this technique more precise, powerful, and easy to use. Today pulsed lasers can be operated with diffraction limited, sub-micrometer precision to ablate intracellular structures. Here, we discuss laser nanosurgery setups and the instrumentation in our laboratory. We describe how to use this technique to ablate cytoskeletal elements in living cells. We also show how this technique can be used in multicellular organisms, to micropuncture and/or ablate cells of interest and finally how to monitor a successful laser nanosurgery.

Laser Power Measurement in Confined Spaces

AbstractA frequent measurement of the laser beam power ensures successful laser processing. Usually, laser systems have a display for laser power. But this display shows the laser power on the laser output and not the laser power at the processing zone. For material processing, it is important to know the effects of the beam guiding system and the processing head on the transmitted laser power. So a laser power measurement as close as possible to the processing zone is preferable. But in many cases, the accessibility of the processing zone is not given for conventional power sensors due to limited space. To enable a greater degree of flexibility, Primes has developed the laser measurement device Cube which will be described below.

The Novel Use of Flexible Ureteroscopy and Holmium: YAG Laser in the Management of Parapelvic Renal Cysts

Kidneys are very common sites of cysts in the human body, prevalence of renal cysts was estimated to be about 10% in the general population and the incidence increases with age. Parapelvic and peripelvic cysts grow near renal collecting system; these types of cysts are most likely to be symptomatic. There are a number of reports describing successful laser incision drainage of parapelvic cysts into the renal pelvis using flexible ureteroscopy transurethrally. This review focuses on specific aspects of clinical usage and novelty of flexible ureteroscopy and holmium laser in the management of parapelvic cysts. A systematic review of articles written in the English language on the subject appearing in the medical journals was conducted using Medline database. Cysts that grow near and inside renal pelvis almost always present with symptoms and require treatment intervention. The intervention is guided by the size of the cyst and severity of the symptoms. Flexible ureteroscopic holmium laser marsupialization of parapelvic cysts is less morbid and complications when compared to laparoscopic decortication approach which is technically very challenging due to the locations of these types of cysts. Retrograde marsupialization of parapelvic cysts is a novel technique which does not need any skin incision at all, thus improving cosmesis after surgery. This approach is a pure and of classical natural orifice transluminal endoscopic surgery (NOTES), it reduces morbidity, mortality, and surgical complications.

First successful satellite laser ranging with a fibre-based transmitter

Satellite laser ranging (SLR) is an established technology used for geodesy, fundamental science and precise orbit determination. This paper reports on the first successful SLR measurement from the German Aerospace Center research observatory in Stuttgart. While many SLR stations are in operation, the experiment described here is unique in several ways: The modular system has been assembled completely from commercial off-the-shelf components, which increases flexibility and significantly reduces hardware costs. To our knowledge it has been the first time that an SLR measurement has been conducted using an optical fibre rather than a coudé path to direct the light from the laser source onto the telescope. The transmitter operates at an output power of about 75mW and a repetition rate of 3kHz, and at a wavelength of 1064nm. Due to its rather small diameter of only 80μm, the receiver detector features a low noise rate of less than 2kHz and can be operated without gating in many cases. With this set-up, clear return signals have been received from several orbital objects equipped with retroreflectors. In its current configuration, the system does not yet achieve the same performance as other SLR systems in terms of precision, maximum distance and the capability of daylight ranging; however, plans to overcome these limitations are outlined.