Comparative study of functional optical zone:small incision lenticule extraction versus femtosecond laser assisted excimer laser keratomileusis

AIM:To investigate the size of functional optical zone(FOZ)after small incision lenticule extraction(SMILE)versus femtosecond laser assisted excimer laser keratomileusis(FS-LASIK)for myopia correction and potential associated factors for FOZ.METHODS:A total of 133 patients who received corneal refractive surgery in our hospital between November 2018 and July 2021 were retrospectively enrolled.There were 63 patients(123 eyes)in SMILE group and 70patients(139 eyes)in FS-LASIK group.The size of FOZ was measured using Pentacam 3-dementional anterior segment analyzer before and 3mo after surgery,so as to analyze postoperative achieved functional optical zone(AFOZ)and its contributing parameters.RESULTS:When planned functional optical zone(PFOZ)was 6.5 mm for both groups,AFOZ was 1.45±0.27 and 1.67±0.25 mm smaller than preoperative FOZ in SMILE group and FS-LASIK group 3mo after surgery.AFOZ in SMILE group was significantly larger than that in FS-LASIK group(P<0.001).Variation of FOZ was negatively correlated with preoperative spherical equivalent(SE)and positively correlated with variation of mean keratometry value(△Km),variation of spherical aberration(△SA),and variation of Q-value(△Q,all P<0.001)in both groups.Multiple variable linear regression equations were△FOZ=1.354-0.1×pre-SE+0.336×△Q+1.462×△SA in SMILE group and△FOZ=1.512+0.137×△Q+0.468×△SA in FS-LASIK group.CONCLUSION:AFOZ is significantly smaller than preoperative FOZ in both SMILE and FS-LASIK groups.With the same PFOZ,larger AFOZ is achieved in SMILE group than in FS-LASIK group.

Successful opening in-stent chronic total occlusion lesion of coronary artery by excimer laser coronary angioplasty

In percutaneous coronary intervention (PCI), chronic total occlusion (CTO) coronary artery disease still remains difficult to treat. One of the reasons for the failure is the hard of the CTO lesions that balloon is difficult to pass through or expand. Previous methods to deal with CTO lesions that cannot be passed by balloon, include selecting reinforced catheter (such as 5 in 6 guiding catheter, Guidzilla catheter, or Tornus microcatheter), guidewire extrusion or rotary grinding technology. In recent years, excimer laser coronary angioplasty (ELCA) has been gradually applied to CTO lesions. Using inert halide as the laser medium, ELCA emits a 308 nm high-intensity unidirectional light wave with absorption depth of only 50 μmL, resulting in less thermal effect and less damage to non-target lesions. In this paper, we will describe a successful PCI case of an in-stent CTO lesion using ELCA with long term coronary angiography follow-up.

Percutaneous recanalization of total saphenous vein graft occlusion with excimer laser treatment

Patients presenting with recurrence of anginal symptoms after saphenous vein bypass surgery pose an increasingly frequent challenge.In general,approximately 40%to 50%of saphenous vein graft(SVG)will become diseased or occluded within the first ten years after surgery.[1]Because adverse clinical outcomes,such as high restenosis rates and distal embolization,have been reported,percutaneous coronary intervention(PCI)for SVG is not recommended as a first-line strategy.[2]Distal embolization occurs in 2%–17%of patients despite advances in therapy,including the utilization of embolic protection device(EPD),which may lead to increased mortality at both short follow-up and midterm follow-up.[3]However,these patients often associated with inappropriate anatomic characteristics of native vessel intervention including calcification,tortuosity,abundant plaque burden,and complex chronic total occlusion(CTO)lesions.Moreover,repeat coronary bypass surgery is an option but is technically more demanding and is associated with a higher mortality.Therefore,it can sometimes result in SVG stenosis being the only intervention option.This is why the recanalization of SVG lesions,especially totally occluded lesions,remains one of the most challenging procedures in interventional cardiology.

Fluorescence spectrum characteristic of ethanol-water excimer and mechanism of resonance energy transfer

The steady-state fluorescence spectrum characteristic of ethanol-water excimer has been studied in this paper. By analysing the features of the sharp emission spectrum with fine structures in a shortwave band and the characteristics of the broad and featureless fluorescence peaks in the longwave band, one can conclude that the excimers are formed between the new ethanol-water cluster molecules in the excited state and the ground state through the interaction among different chromophores. The excitation spectra in the two fluorescence bands have been studied, and their emission mechanisms have been ascertained based on the energy transfer theory. Furthermore, the critical distance of the resonance energy transfer has been calculated.

Nickel-disilicide-assisted excimer laser crystallization of amorphous silicon

Polycrystalline silicon （poly-Si） thin film has been prepared by means of nickel-disilicide （NiSi2） assisted excimer laser crystallization （ELC）. The process to prepare a sample includes two steps. One step consists of the formation of NiSi2 precipitates by heat-treating the dehydrogenated amorphous silicon （a-Si） coated with a thin layer of Ni. And the other step consists of the formation of poly-Si grains by means of ELC. According to the test results of scanning electron microscopy （SEM）, another grain growth model named two-interface grain growth has been proposed to contrast with the conventional Ni-metal-induced lateral crystallization （Ni-MILC） model and the ELC model. That is, an additional grain growth interface other than that in conventional ELC is formed, which consists of NiSi2 precipitates and a-Si. The processes for grain growth according to various excimer laser energy densities delivered to the a-Si film have been discussed. It is discovered that grains with needle shape and most of a uniform orientation are formed which grow up with NiSi2 precipitates as seeds. The reason for the formation of such grains which are different from that of Ni-MILC without migration of Ni atoms is not clear. Our model and analysis point out a method to prepare grains with needle shape and mostly of a uniform orientation. If such grains are utilized to make thin-film transistor, its characteristics may be improved.

Understanding the effects of excimer laser treatment on corrosion behavior of biodegradable Mg-1Ca alloy in simulated body fluid

In this study,a KrF excimer laser was used to modify the biodegradable Mg-1Ca alloy and the time-evolution degradation behavior of the alloy before and after laser treatment was investigated in simulated body fluid(SBF)solution using immersion tests and electrochemical impedance spectroscopy(EIS).A 5μm melted layer with a homogeneous microstructure and an MgO film on the surface were achieved by laser radiation.Corrosion observations(hydrogen evolution,morphology and corrosion products)and EIS results revealed an improvement of corrosion resistance after laser treatment for 48 h.It was found a two-layer structure developed after 2 h immersion on both the untreated and laser-treated alloys,but the sequence of forming the two layers was opposite and greatly influenced by the laser-treated layer.The time-evolution corrosion processes on the untreated and laser-treated alloys were discussed,providing a better understanding of corrosion behavior of biodegradable Mg alloys modified by excimer laser.

Multiple excimer laser phototherapeutic keratectomies for Avellino corneal dystrophy:a case report

Dear Editor,I am Chihiro Koiwa,from the Department of Ophthalmology,Juntendo University Hospital.I am writing this letter to present a case of multiple excimer laser phototherapeutic keratectomies(PTKs)for Avellino corneal dystrophy(ACD).Corneal dystrophy is a common type of hereditary,noninflammatory,and bilateral corneal disorder that involves various pathological,histological,and clinical manifestations[1].Advanced molecular gene sequencing has identified specific mutations that are associated with most dystrophies of this type.ACD,also known as granular corneal dystrophy typeⅡ[2],is autosomal dominant and associated with the R124H mutation of the transforming growth factor beta-induced(TGFBI)gene and characterized by deposits consistent with both discrete granular and lattice corneal opacities[3-4].An analysis of the TGFBI gene is essential to differentiate ACD because heterozygous R124H mutation carriers have minimal corneal abnormalities,whereas homozygotes have severe visual impairment,starting from early childhood,and early postoperative recurrence of corneal opacity.

The Characteristics of Dielectric Barrier Discharge and its Influence on the Excimer XeCl Emission

In this work, the influence of discharge modes on the excimer XeCl emission (308 nm) has been studied by adding helium gas into the xenon and chlorine mixture. It is found that the transition from filament discharge to glow /filament - combined discharge leads to the decrease in excimer emission. We are the first one to use a flowing water film as an outer transparent electrode, and achieve a higher UV intensity, compared with the case by using a metal mesh as the outer electrode. The influence of the gas temperature both in the reactor Tg and in a discharge channel Tc on the excimer emission has been analyzed preliminarily. Finally, it has been expected that the replacement of chlorine gas Cl2 by another chlorine gas may reduce the heat generated in the discharge processes and give rise to the excimer XeCl* radiation.

Simple Detection Method of Biogenic Amines in Decomposed Fish by Intramolecular Excimer Fluorescence

Biogenic amines are known to have various biological functions such as not only neurotransmitter and cell proliferation but also food poisoning. Bacterially-decomposed amines such as histamine, agmatine, putrescine, cadaverine, spermidine and spermine cause allergic symptoms. We developed simple method for measurement of polyamine as indicator of food decomposition with a fluorometer by using 4-(1-Pyrene)butyric acid N-hydroxysuccinimide ester (PSE). PSE reacts with primary and secondary amino moieties of polyamines and produces the intramolecular excimer fluorescence. Excimer fluorescence with broad peak at around 470 nm was clearly detected in linear type biogenic amines such as putrescine, cadaverine, spermidine and spermine at 10 mM. However neither histamine nor trimethylamine altered the fluorescence. Decomposed sardine and mackerel by improper storage showed stronger intensity than fresh ones. Comparing with OPA-method, PSE method was useful for screening biogenic amines present in food, esp. fish since the analysis was simple after one-step purification procedure. An inexpensive system which can rapidly detect biogenic amines from food is necessary in a medium and small-sized food business. The technique using excimer has potential to realize the high through-put screening system for evaluation of food freshness and is expected to bring the public interests such as food security and safety of consumer.

CLINICAL ANALYSIS OF EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY FOR TREATMENT OF MYOPIA AND MYOPIC ASTIGMATISM

To evaluate the efficacy and accuracy of photorefractive keratectomy (PRK) for myopia and myopic astigmatism .SVS APEX excimer laser with a wave length of 193 nm(Sumit Technology Inc. Waltham, Mass, USA) was applied. 316 myopic eyes of 168 patients were treated with PRK between September, 1996 and October, 1997, and 260 eyes (84%) of 150 patients were followed for more than three months, including male 68(116 eyes, 401%) and female 82(144 eyes, 599%). The preoperative spherical equivalent refractive errors ranged from -125D to -1000 (mean -467163D), and astigmatism ranged from 0 to -200D (means -033045D). We divided the patients into two groups according to the referaction: group A (from -125D to -590D) and group B(from -600 to -1000D). The number of eyes in the two groups were 220 and 40 respectively. In group A, on the 10th day, 689% has the uncorrected visual acuity (UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity (BCVA). In 1,3,6 and 12 months, 90 %, 96%, 95% and 94% had the UCVA equal to or one line better or lower than the preoperative BCVA respectively. In group B, on the 10 th day, in 1,3,6 and 12 months, UCVA equal to or one line better or lower than the preoperative BCVA occurred in 359%, 83%, 87%, 86%, and 84% of the cases respectively. Most of the haze showed 051 grades except 3 eyes with the haze of 2 grade in 3 or 6 months and it changed to 1 and 05 grade respectively within one year. In 10 days and 1,3,6,12 months postoperatively, the corneal haze was noted in 329%, 848%, 628%,90% and 28% of the treated eyes respectively. We found that 193 nm excimer laser PRK was a predictable, safe, stable, and effective refractive surgery for correcting myopia up to -1000D in Chinese patients, and the effect was better in myopia lower than -600D.

Excimer紫外灯辐照法钽氧化物膜XPS分析

报道了利用新型紫外光源—Ｅｘｃｉｍｅｒ紫外灯辐照制备钽氧化物薄膜的新方法，并对所制备的薄膜进行了Ｘ光光电子能谱（ＸＰＳ）分析，分析结果表明：所制备的钽氧化物薄膜不含碳而且符合化学计量比。

Phosphorus diffusion and activation in fluorine co-implanted germanium after excimer laser annealing

The diffusion and the activation of phosphorus in phosphorus and fluorine co-implanted Ge after being annealed by excimer laser are investigated.The results prove that the fluorine element plays an important role in suppressing phosphorus diffusion and enhancing phosphorus activation.Moreover,the rapid thermal annealing process is utilized to evaluate and verify the role of fluorine element.During the initial annealing of co-implanted Ge,it is easier to form high bonding energy FnVm clusters which can stabilize the excess vacancies,resulting in the reduced vacancy-assisted diffusion of phosphorus.The maximum activation concentration of about 4.4 ×10^(20) cm^(-3) with a reduced diffusion length and dopant loss is achieved in co-implanted Ge that is annealed at a tailored laser fluence of 175 mJ/cm^(2).The combination of excimer laser annealing and co-implantation technique provides a reference and guideline for high level n-type doping in Ge and is beneficial to its applications in the scaled Ge MOSFET technology and other devices.

Comparison of clinical outcomes of deep anterior lamellar keratoplasty and excimer laser assisted anterior lamellar keratoplasty in keratoconus

AIM: To compare and evaluate the clinical outcomes of deep anterior lamellar keratoplasty(DALK) and excimer laser assisted anterior lamellar keratoplasty(ELLK) in eyes with keratoconus.METHODS: In this study, 57 eyes of 56 patients operated between 2013 to 2017 were included. Thirty-one eyes underwent big-bubble DALK and twenty-six eyes underwent ELLK. Preoperative and at control visits complete ophthalmic examination was performed. RESULTS: The mean patient age at the time of DALK surgery was 27 y and mean follow-up period was 21±5.4 mo. The mean patient age at the time of ELLK surgery was 27 y and mean follow-up period was 40±18 mo. Mean best spectacle corrected visual acuity(BSCVA) at postoperative period was significantly higher for DALK group(0.66±0.11) versus ELLK group(0.4±0.2)(P<0.05). Descemet's membrane microperforation was occurred in 7 patients in DALK group versus in 1 patient in ELLK group. In 4 eyes, interface irregularity was developed in ELLK group. None of the patients in follow-up had graft rejection in both groups.CONCLUSION: In ELLK group, complication rate is lower, the surgical technique is simpler, faster and safer and also ELLK requires less experience with respect to DALK. Further, DALK can be performed unless satisfactory visual acuity is achieved after ELLK.

Formation of High-quality Advanced High-k Oxide Layers at Low Temperature by Excimer UV Lamp-assisted Photo-CVD and Sol-gel Processing

We have successfully demonstrated that high quality and high dielectric constant layers can be fabricated by low temperature photo-induced or -assisted processing. Ta_2O_5 and ZrO_2 have been deposited at t<400 ℃ by means of a UV photo-CVD technique and HfO_2 by photo-assisted sol-gel processing with the aid of excimer lamps. The UV annealing of as-grown layers was found to significantly improve their electrical properties. Low leakage current densities on the order of 10 -8 A/cm 2 at 1 MV/cm for deposited ultrathin Ta_2O_5 films and ca.10 -6 A/cm 2 for the photo-CVD ZrO_2 layers and photo-irradiated sol-gel HfO_2 layers have been readily achieved. The improvement in the leakage properties of these layers is attributed to the UV-generated active oxygen species O( 1D) which strongly oxidize any suboxides to form more stoichiometric oxides on removing certain defects, oxygen vacancies and impurities present in the as-prepared layers. The photo-CVD Ta_2O_5 films deposited across 10.16-cm Si wafers exhibit a high thickness uniformity with a variation of less than \{±2.0%\} being obtained for ultrathin ca.10 nm thick films. The lamp technology can in principle be extended to larger area wafers, providing a promising low temperature route to the fabrication of a range of high quality thin films for future ULSI technology.

Excimer and Micellization of a Merocyanine

Excimers are molecular associates which exist only in excited electronic states so that they are detectable only in eemission spectra,especially in fluorescence spectra,This fluorescent phenomenon has also been observed for some stable aggregates in which molecules are arranged in a special form.Excimer fluorescence component should be affected by associate state in stable or metastable aggregates.It leads us to studying micellization by means of fluorescence spectroscopy.

Effect of open ultraviolet germicidal irradiation lamps on functionality of excimer lasers used in cornea surgery

We report on the impact of direct ultraviolet germicidal irradiation（UVGI）on reflective optics,used in the excimer laser system Allegretto Eye-Q.The aim of our work was to confirm our hypothesis based on long-rate observations of obtained anomalies in post-operative results that are attributed to degradation of reflective optics upon ultraviolet radiation.The presence of direct UVGI coupled with humidity in the operating environment caused merging anomalies and unwanted post-operative correction values.Ultraviolet-A radiation caused a similar effect on the reflective cover of the mirrors.

ON SELF-ABSORPTION CORRECTION IN EXCIMER FLUORESCENCE MEASUREMENTS OF POLYMER SOLUTIONS

The effect of self absorption on the ratio of excimer to monochromophore emission intensities, I-e/I-m, has been explored by experimentally changing the solution layer thickness of the emission light path traversed in the solution in the right-angle geometry. The result shows that data obtained by front-face geometry are better than those obtained by right-angle geometry even after correction to zero solution thickness. The correction formula based on geometric optics given by Tsai and Torkelson is not adequate.

The Characteristics of the Surface Topography of Excimer Laser Processed Al_2O_3 Ceramic

Surface of Al 2O 3 ceramic was processed by an excimer laser and the characteristics of topography were examined based on the application of the microelectromechanical system(MEMS). It is indicated that the statistic parameters of surface topography processed by the excimer laser have an obvious regularity. The arithmetic-mean value R a and the root-mean square value R q change with the changing of processing parameters in the same step and trend, and there is a quantitative relation between them.A simplified model is proposed for the excimer laser processing surface profile, whose results of the analysis and calculation agree basically with the experimental data. Furthermore,the surfaces processed by excimer laser are greatly flat. Skewness root-mean-square value Z· q changed little with the change of the technological parameters. The above characteristics depend on the processing principle of excimer laser, quite different from the cutting processing.

Excimer laser coronary atherectomy for a severe calcified coronary ostium lesion:A case report

BACKGROUND Percutaneous coronary intervention can be challenging for ostial coronary artery lesions due to calcium burden and elastic fiber content.Excimer laser coronary atherectomy(ELCA)is a less common treatment for severe calcified coronary ostium lesions.CASE SUMMARY An 81-year-old male presented to the Cardiology Department of Qingdao Municipal Hospital with a 1-year history of chest pain.Coronary angiography showed severe calcific stenosis(approximately 90%)in the right coronary artery ostium.The right coronary artery ostium was unable to be advanced using a 2.5 mm×12.0 mm balloon(NC Sprinter,Medtronic,United States)or dilated using a 2.0 mm×12.0 mm balloon(Sprinter,Medtronic,United States).The patient underwent successful ELCA and balloon dilation of the calcified coronary ostium lesion.CONCLUSION ELCA appears to be a safe and effective treatment for the management of severe calcified coronary ostium lesions.

Experimental Study on the Early Efficacy of Excimer Laser with Adjunctive Balloon Angioplasty in Dog＇s Femoral Artery

The effect of domestically-manufactured excimer laser with adjunctive balloon angioplasty in achieving revascularization and reduction of residual stenosis was assessed. 20 femoral arteries with thrombosis and occlusion from 12 dogs were subject to angiography. At first excimer laser angioplasty was done followed by balloon angioplasty. The diameter and residual stenosis of revascularized vessel were measured. The result showed that 17 out of 20 vessels (85 %) were revascularized. The diameter of revascularized vessel by excimer laser were 1. 22±0.14 mm,while residual stenoses were 54 %±5%. After adjunctive balloon angioplasty the diameter and residual stenoses were 2. 04±0. 16 mm and 20 %±7 %respectively (P<0. 05 and P<0. 01), Complication in form of vasoperforation occurred in 3/20 vessels (15%). It is concluded that China-manufactured excimerlaser angioplasty is effective when used for revascularization. While the reduction of narrowing and residual stenoses was enhanced after adjunction of balloon angioplasty. This method can be employed in treating peripheral occlusive disease effectively and safely.