scholarly journals Treatment of seborrheic keratosis with a copper vapour laser

2019 ◽  
Vol 95 (3) ◽  
pp. 25-33
Author(s):  
S. V. Klyuchareva ◽  
I. V. Ponomarev ◽  
S. B. Topchiy ◽  
A. E. Pushkareva ◽  
Yu. N. Andrusenko
Keyword(s):  
Computer Simulation ◽  
Energy Deposition ◽  
Average Power ◽  
Skin Surface ◽  
Copper Vapour Laser ◽  
Seborrheic Keratosis ◽  
Tissue Heating ◽  
Laser Systems ◽  
Deposition Depth

Aim: to assess the efficacy and side-effect risk of the surgical treatment of seborrheic k eratosis (SK) using a copper vapour laser (CVL).Patients and methods. 3980 patients (1214 men and 2766 women aged 20 to 78 years) suffering from SK were treated using a CVL (Yakhroma-Med model, Russian producer) equipped with a laser pen and a scanning nozzle. The laser treatment was performed without anaesthesia in one to four sessions. During the treatment procedure, the following radiation parameters were applied: wavelengths ranging from 511 to 578 nm (in the ratio of 3 to 2), an average power of 0.6–1.2 W and an exposure duration ranging from 0.2 to 0.4 s. The diameter of the light spot on the skin surface was 1 mm. The follow-up observation lasted 24 months.Results. The computer simulation of tissue heating by CVL and other laser systems showed that CVL is an optimal treatment choice for seborrheic keratosis in terms of the energy deposition depth. According to our clinical data and the results of computer simulation, the CVL is established to be the safest and the most effective for seborrheic keratosis treatment.

scholarly journals Study on X-ray Induced Two-Dimensional Thermal Shock Waves in Carbon/Phenolic

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3553
Author(s):  
Dengwang Wang ◽  
Yong Gao ◽  
Sheng Wang ◽  
Jie Wang ◽  
Haipeng Li
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Wave Propagation ◽  
Thermal Shock ◽  
Anisotropic Material ◽  
Energy Deposition ◽  
X Rays ◽  
Two Dimensional ◽  
X Ray ◽  
Deposition Depth

Carbon/Phenolic (C/P), a typical anisotropic material, is an important component of aerospace and often used to protect the thermodynamic effects of strong X-ray radiation. In this paper, we establish the anisotropic elastic-plastic constitutive model, which is embedded in the in-house code “RAMA” to simulate a two-dimensional thermal shock wave induced by X-ray. Then, we compare the numerical simulation results with the thermal shock wave stress generated by the same strong current electron beam via experiment to verify the correctness of the numerical simulation. Subsequently, we discuss and analyze the rules of thermal shock wave propagation in C/P material by further numerical simulation. The results reveal that the thermal shock wave represents different shapes and mechanisms by the radiation of 1 keV and 3 keV X-rays. The vaporization recoil phenomenon appears as a compression wave under 1 keV X-ray irradiation, and X-ray penetration is caused by thermal deformation under 3 keV X-ray irradiation. The thermal shock wave propagation exhibits two-dimensional characteristics, the energy deposition of 1 keV and 3 keV both decays exponentially, the energy deposition of 1 keV-peak soft X-ray is high, and the deposition depth is shallow, while the energy deposition of 3 keV-peak hard X-ray is low, and the deposition depth is deep. RAMA can successfully realize two-dimensional orthotropic elastoplastic constitutive relation, the corresponding program was designed and checked, and the calculation results for inspection are consistent with the theory. This study has great significance in the evaluation of anisotropic material protection under the radiation of intense X-rays.

Computer Simulation of Gamma Irradiation Energy Deposition in MOSFET Dosimeters

2006 ◽  
Vol 34 (5) ◽  
pp. 1715-1718 ◽  
Author(s):  
S.J. Stankovic ◽  
R.D. Ilic ◽  
P. Osmokrovic ◽  
B. Loncar ◽  
A. Vasic
Keyword(s):  
Computer Simulation ◽  
Gamma Irradiation ◽  
Energy Deposition ◽  
Irradiation Energy

High-power ultrafast thin-disk multipass amplifiers for efficient laser-based manufacturing

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Marwan Abdou Ahmed ◽  
Christoph Roecker ◽  
André Loescher ◽  
Florian Bienert ◽  
Daniel Holder ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
State Of The Art ◽  
Second Harmonic ◽  
Average Power ◽  
Polycrystalline Diamond ◽  
Third Harmonic Generation ◽  
Thin Disk ◽  
Ultrafast Laser ◽  
Third Harmonic ◽  
Laser Systems

Abstract Thin-disk multipass amplifiers represent one of the most powerful approaches to scale the average and peak powers of ultrafast laser systems. The present paper presents the amplification of picosecond and femtosecond pulses to average powers exceeding 2 and 1 kW, respectively. Second-harmonic generation in lithium-triborate crystals with powers higher than 1.4 kW and 400 W at a wavelength of 515 nm with picosecond and femtosecond pulse durations, respectively, are also reported. Furthermore, third-harmonic generation was demonstrated with output powers exceeding 250 W at a wavelength of 343 nm. Finally, processing of silicon, metals, and polycrystalline diamond with fs pulses at an average power of 1 kW is presented to demonstrate removal rates that are improved by orders of magnitude as compared to state-of-the-art techniques.

YAG:Yb crystal with non-linear doping ions distribution as promising active element for high average power laser systems

Laser Physics ◽  
2021 ◽  
Vol 31 (3) ◽  
pp. 035003
Author(s):  
V A Petrov ◽  
V V Petrov ◽  
G V Kuptsov ◽  
A V Laptev ◽  
V V Galutskiy ◽  
...  
Keyword(s):  
Active Element ◽  
Average Power ◽  
High Average Power ◽  
Power Laser ◽  
Non Linear ◽  
Laser Systems

Hebb-Type Dynamics is Sufficient to Account for the Inverse Magnification Rule in Cortical Somatotopy

1990 ◽  
Vol 2 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Kamil A. Grajski ◽  
Michael M. Merzenich
Keyword(s):  
Computer Simulation ◽  
Receptive Field ◽  
Cortical Neuron ◽  
Inverse Relationship ◽  
Unit Area ◽  
Skin Surface ◽  
Field Size ◽  
Synaptic Modification ◽  
Somatotopic Map ◽  
Cortical Magnification

The inverse magnification rule in cortical somatotopy is the experimentally derived inverse relationship between cortical magnification (area of somatotopic map representing a unit area of skin surface) and receptive field size (area of restricted skin surface driving a cortical neuron). We show by computer simulation of a simple, multilayer model that Hebb-type synaptic modification subject to competitive constraints is sufficient to account for the inverse magnification rule.

scholarly journals Non-contact radiofrequency-induced reduction of subcutaneous abdominal fat correlates with initial cardiovascular autonomic balance and fat tissue hormones: safety analysis

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 49 ◽  
Author(s):  
Jiri Pumprla ◽  
Kinga Howorka ◽  
Zuzana Kolackova ◽  
Eliska Sovova
Keyword(s):  
Autonomic Function ◽  
Spectral Power ◽  
Low Frequency ◽  
Abdominal Fat ◽  
Autonomic Response ◽  
Abdominal Circumference ◽  
Autonomic Balance ◽  
Fat Tissue ◽  
Tissue Heating

Background and objective: The non-invasive reduction of subcutaneous abdominal fat became popular in the last decade. Radiofrequency (RF), non-contact, selective-field device Vanquish® has been developed to selectively induce deep fat tissue heating to reduce waist circumference. Our analysis evaluates immediate and sustained effects of this treatment on cardiovascular autonomic function and on selected metabolic parameters.Study design/patients and methods: A retrospective proof-of-concept analysis of RF treatment effects was conducted in 20 individuals with metabolic syndrome, to reduce the subcutaneous abdominal fat. Four 30-minutes treatment sessions (manufacturer´s standard protocol) were performed in 1-week intervals. Vital signs, ECG, lab screening, body composition, subcutaneous fat thickness and spectral analysis of heart rate variability (HRV) have been examined before, after the 1st and 4th treatment, and at follow-up visits 1 month and 3 months after the treatment.Results: The RF treatment led to a significant reduction of abdominal circumference after the 4th session (p<0.001), and during follow-up after 1 and 3 months (p<0.001 and p<0.02, resp.). There was a significant correlation (r=-0.58, p=0.007) between reduction of abdominal circumference and initial very-low frequency (VLF) spectral power at 1 month follow-up. A significant increase of cumulative spectral power in low frequency (p=0.02) and reduction in high frequency (p=0.05) band have been observed immediately (20+14 minutes) after the treatment. On the contrary, no sustained impact on autonomic balance has been recorded 39+18 days after the treatment. A significant correlation between the initial adiponectin values and immediate autonomic response to one treatment was observed in VLF and total spectral bands (r>0.59, p<0.04).Conclusions: Our analysis shows that the selective-field RF treatment is safe and efficient for reduction of subcutaneous abdominal fat. While the treatment increases the immediate sympathetic response of the body to deep tissue heating, no sustained change in autonomic function could be recorded at 1 month follow-up. The observed correlation between initial VLF spectral power and waist circumference reduction at follow-up, as well as the association of initial adiponectin values and immediate autonomic response to the treatment might be instrumental for decisions on body contouring strategies.

scholarly journals Comparative Study of Surgical Treatment of Chalazion

2015 ◽  
Vol 9 (2) ◽  
pp. 68-69
Author(s):  
Khandaker Anowar Hossain ◽  
Md Abdur Rashid ◽  
AKM Rafiqul Islam
Keyword(s):  
Inflammatory Lesion ◽  
Skin Surface ◽  
Meibomian Gland ◽  
Medical College ◽  
Large Size ◽  
Intralesional Steroid ◽  
Intralesional Steroid Injection ◽  
Group A ◽  
Group B

A chalazion is chronic lipogranulomatous inflammatory lesion caused by blockage of meibomian gland orifices & stagnation of sebaceous secretion. Common practices in treatment of chalazion are intralesional steroid injection, incision & curettage and excision of chalazion. Recurrence rate is high for incision & curettage in case of large chalazion. The aim of the study is to established that excision large chalazion give better result than incision & curettage. The study was carried out at Diabetic Association Medical College & Hospital, Faridpur and General Hospital, Fadidpur. A total 100 cases were selected for study. Technique of operation were incision & curettage through conjunctival surface and excision of chalazion through skin surface. In 50 % cases we performed incision & curettage both in small (size <5mm) and large (size >5mm) chalazion. In 50 % cases of large chalazion we performed excision of chalazion. The follow up period was 3 months to 6 months. In group -A with incision & curettage through conjunctival surface, in case of small chalazion 27 out of 30 patients were cured (90%). In case of large chalazion 14 out of 20 patients were cured (70%). In group B with excision of chalazion through skin surface, in case of large chalazion 49 out of 50 patients were cured (98%). So higher success rate after excision of large chalazion through skin surface.Faridpur Med. Coll. J. 2014;9(2): 68-69

scholarly journals Dermatoses in parkinsonism: the importance of multidisciplinary follow-up

2019 ◽  
Vol 65 (6) ◽  
pp. 791-795 ◽  
Author(s):  
Isadora Antunes ◽  
Kátia Sheylla Malta Purim ◽  
Luara Leticia Grande ◽  
Nathália Cristina Alberton ◽  
Tatiana Francinne Regis Navarro ◽  
...  
Keyword(s):  
Actinic Keratosis ◽  
Seborrheic Dermatitis ◽  
Skin Lesions ◽  
Disease Diagnosis ◽  
Seborrheic Keratosis ◽  
Cross Sectional ◽  
Inflammatory Dermatoses ◽  
Malignant Skin ◽  
Pigmented Nevus

Summary Parkinsonism is characterized by bradykinesia with rigidity and/or resting tremor, in addition to non-motor symptoms, which include dermatological manifestations. The objective of this study is to evaluate the main dermatoses in patients with parkinsonism found at the Philanthropic Association of Curitiba - PR. A cross-sectional descriptive study was carried out with the application of a questionnaire and dermatological evaluation of the patients. The sample consisted of 386 patients and was composed mainly by men (55.4%), between 60-74 years old (51.6%), with complete primary education (45.3%), disease diagnosis time between 5-10 years (35%) and in use of medication (96.6%). The most prevalent dermatoses were pigmented nevus (36.3%), warts (25.1%), actinic keratosis (22%), seborrheic keratosis (21.5%), seborrheic dermatitis (20.5%), and rosacea (19.2%). Among the 13 cases (3.4%) of malignant cutaneous neoplasms confirmed by biopsy, 2 were melanomas. Regarding patients’ sex, there was a higher prevalence of inflammatory dermatoses (OR 1.64, 95% CI 1.08-2.51, p = 0.025) and benign cutaneous neoplasms (OR 1.77, 95% CI 1.16-2.69, p = 0.01) in men. As to age, patients aged between 60-74 years had more pre-malignant skin lesions (OR 2.60, 95% CI 1.05-6.44, p <0.001) and seborrheic keratosis (OR 2.52, 95% CI 1.02-6.25, p = 0.001) and, in those older than 75 years, actinic keratosis was more frequent (OR 5.43, 95% CI 2.17-13.6, p <0.001). The results of the study show that it is fundamental to dermatologically evaluate and monitor these patients, aiming at diagnosis and early treatment of lesions, especially of skin cancer.

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