Laser-assisted Device Research Articles

The P&P Hairline Laser: A Novel Hands-Free Laser-Assisted Hairline Device for Hair Restoration Surgery

<h3>Background:</h3> There are many methods to try to achieve symmetry in hairline design, for example, by using eyesight to adjust the drawing or by using measurements with a ruler, but it is difficult to do when there is no anatomical landmark to use. Here, we compare our hands-free, laser-assisted device—the P&amp;P Hairline Laser—with the widely used original handheld laser device. Our goal was to achieve better symmetry by providing a fix for the difficulty in stabilizing the handheld device to the forehead while drawing the hairline. <h3>Method:</h3> We invented a new hands-free, laser-assisted hairline device that can be used in several ways such as for placing a hairline (male or female), placing a posterior hairline, placing a symmetrical strip scar for FUT, and measuring scalp laxity. We have been testing this device on our patients (both men and women) at the DHT clinic since 2020. <h3>Results:</h3> After using and testing this hands-free device in almost 100 patients, we are satisfied with the results and have concluded that the hairline that is traced and drawn by our enhanced device is very smooth compared with the one created by the original handheld device. <h3>Discussion:</h3> The P&amp;P Hairline Laser is convenient and lightweight and allows the surgeon to achieve a symmetrical hairline in less than a minute. It also can be used to draw the posterior hairline, eyebrows, beard cheek lines, and mustache; and it can be used to outline a strip incision symmetrically as well as measure scalp laxity. We feel by being hands-free and able to affix to the forehead, our device provides a benefit over the currently used handheld device.

Spectroscopic Characterization of Emulsions Generated with a New Laser-Assisted Device.

This paper presents a spectroscopic study of emulsions generated with a laser-assisted device. Fourier transform infrared (FTIR), Raman and UV–Vis–NIR reflectance spectra of emulsions, recorded before and after exposure to laser radiation were used to characterize the effect of laser irradiation. The paper also presents a comparison between the calculated IR spectra and the experimental FTIR spectra of an emulsion’s components. FTIR measurements allowed the identification of absorption bands specific to each of the emulsions’ components. Moreover, it enabled the observation of destabilization of the emulsion in real-time. Raman spectroscopy allowed the observation of the modifications at a molecular level, by identifying the vibrations of the representative functional groups and the polymerization of sodium tetradecyl sulfate (STS) molecules by analyzing the evolution of the carbonyl band. UV–Vis–NIR reflectance spectra of emulsions before and after exposure to laser radiation showed that the physical characteristics of the emulsions changed during irradiation—the dimensions of the droplets decreased, leading to an emulsion with a better time stability. These results proved that the employed spectroscopy techniques were powerful tools in emulsion analysis.

Laser assisted generation of micro/nanosize emulsions

Emulsification methods are of interest for numerous fields and those that generate nanoemulsions are, particularly, of great interest for medical applications. This paper presents a new laser-assisted device that may generate pharmaceutical emulsions. One of its advantages is that allows the use of small quantities of solutions, as low as a few hundreds of μl. It also allows to set the number of mixing cycles and mixing speeds. Emulsions of Sodium tetradecyl sulfate (STS) solution in water and oily vitamin A were generated without additional stabilizers. Optical microscopy, dynamic light scattering and surface tension analysis of a pendant drop were employed to compare the unirradiated emulsions with the ones exposed to laser radiation at 532 nm. Results showed that laser radiation decreases and homogenizes droplets dimensions. Furthermore, irradiation increases the stability of the emulsions. The wavelength of laser radiation is selected so that it is not absorbed by molecules in the immiscible solutions. In this way the energy of laser radiation leads to droplet break-up and generation of new, smaller droplets.

Cueing Effect of Gait Ability in Parkinson’s Disease

Abnormal gait patterns are commonly found in patients with Parkinson’s disease (PD). These often consist of short shuffling steps, decreased walking speed, increased cadence and freezing of gait. External cues have been tested for improving gait ability in patients with PD. Advanced rehabilitation techniques have been evidenced over the years: these included treadmill walking, direct current stimulation, transcranial magnetic stimulation and ground training with cues. Traditionally, visual cues had been used in the form of a series of strips located on the floor in transverse lines for the patient to walk over and pole striding which has been shown to reduce gait variability. In addition, laser guided-walking cues have been proposed which can be in the form of goggles with a light emitting diode (LED), laser guided-walking cane, or a laser-assisted device (LAD).

Optical and dielectric studies of KH2PO4 crystal influenced by organic ligand of citric acid and l-valine: A single crystal growth and comparative study

In the present study pure, citric acid (CA) and l-valine (LV) doped potassium dihydrogen phosphate (KDP) crystals have been grown with the aim to investigate the nonlinear optical applications facilitated by UV–visible, third order nonlinear optical (TONLO) and dielectric properties. The structural parameters of grown crystals have been confirmed by single crystal X-ray diffraction analysis. The enhancement in optical transparency of KDP crystal due to addition of CA and LV has been examined within 200–900nm by means of UV–visible spectral analysis. In addition, the transmittance data have been used to evaluate the effect of dopants on reflectance, refractive index and extinction coefficient of grown crystals in the visible region. The Z-scan analysis has been performed at 632.8nm to identify the nature of photoinduced nonlinear refraction and nonlinear absorption in doped KDP crystals. The influence of π-bonded ligand of dopant CA and LV on TONLO susceptibility (χ3), refractive index (n2) and absorption coefficient (β) of KDP crystals has been evaluated to discuss laser assisted device applications. The decrease in dielectric constant and dielectric loss of KDP crystal due to addition of CA and LV has been explored using the temperature dependent dielectric studies.

Engineering and experimental testing of two-wavelength laser-assisted device for photocoagulation of eye tissue

Retinal photocoagulation is believed to be one of most efficient methods to treat many retinal abnormalities. By now, a number of lasers operating at different wavelengths, irradiation intensities, and exposure times have been tested in search of optimal parameters for each type of retinal photocoagulation. Taking into consideration a wide range of such parameters, the primary objective of the present study was to develop a device that would combine the potentials of different lasers into a single universal laser-assisted coagulator (ULAC) equally suitable for a wide diversity of retinal disease. Important issue would be the creation of an experimental model allowing an operative evaluation of the coagulating effect induced by the ULAC. The sources of coherent irradiation to be combined were DPSS and diode lasers (532 and 810 nm, respectively). Through two individual fibers, irradiation generated by each of the lasers entered the optical blender to be further directed to the target, now via a single fiber. The target termed the “surrogate of living tissue” was a mixture of donor human blood and chicken egg white, which corresponded, respectively, to the chromophore and thermocoagulating agent, both sensitive to laser beams at 532 and 810 nm. As a result, irradiation of surrogate of living tissue by a laser under the trial caused the formation of a coagulate and its firm adhesion to the coverslip, after that the coagulate was separated from the unaffected surrogate of living tissue followed by its 3D-analysis. In conclusion, the whole procedure, while being relatively non-expensive and easy to perform, has proved to be simple enough for testing of a wide spectrum of coagulation-inducing parameters, whatever laser was used. Moreover, even the initial experiments have shown the high efficiency of the ULAC as a potential candidate for the application in ophthalmological practice.

Application of Advanced Back-Side Optical Techniques in ASICs

Failure analysis is important in determining root cause for appropriate corrective action. In order to perform failure analysis of microelectronic application-specific integrated circuits (ASICs) delidding the device is often required. However, determining root cause from the front side is not always possible due to shadowing effects caused by the ASIC metal interconnects. Therefore, back-side polishing is used to reveal an unobstructed view of the ASIC silicon transistors. This paper details how back-side polishing in conjunction with laser-scanned imaging (LSI), laser voltage imaging (LVI), laser voltage probing (LVP), photon emission microscopy (PEM), and laser-assisted device alterations (LADA) were used to uncover the root cause of failure of two ASICs.

Two-photon absorption laser assisted device alteration using continuous wave 1,340 nm laser

We report several cases of two photon absorption (TPA) laser assisted device alteration (LADA) using continuous wave (CW) 1,340 nm laser in Si Complimentary Metal-Oxide Semiconductor (CMOS) Integrated Circuits (IC). Two photon absorption using CW 1,340 nm laser in Si was confirmed by photon beam induced photocurrent measurements. TPA LADA showed greater than two times better resolution in critical timing circuit defect localization and debug application, when compared with traditional single photon absorption (SPA) LADA with CW 1,064 nm laser. A simplified analysis on the resolution improvements presented here showed in good agreement with our experimental observations. Further enhancements of this technology are outlined, which we believe will enable this technology for critical timing circuit debug capabilities well into the future generations of Si CMOS Debug applications.

Subchondral Fracture Following Arthroscopic Knee Surgery

Osteonecrosis has been reported as a rare complication of arthroscopic knee surgery, with the diagnosis based on radiographic findings associated with recurrent or worsening clinical symptoms. The term osteonecrosis has been applied to this clinical entity despite a lack of pathologic evidence to support the diagnosis. The purpose of this study was to document the pathologic changes involved in this rare process. Patients who had undergone an arthroscopic procedure followed by a total knee replacement within two years were eligible for the study. Inclusion criteria included pre-arthroscopy magnetic resonance imaging findings consistent with a meniscal tear with otherwise normal bone morphology followed by a provisional diagnosis of post-arthroscopy osteonecrosis based on subsequent imaging studies. Patients were excluded if a laser-assisted device had been utilized during the arthroscopy. Seven patients (eight knees) with an average age of sixty-four years met the criteria and were included in the study group. All patients had undergone an arthroscopic medial meniscectomy, and two also had had a chondroplasty, with use of a mechanical shaver. Seven of the post-arthroscopy lesions involved the medial femoral condyle, and one lesion involved the medial tibial plateau. Pathologic analysis revealed a subchondral fracture with callus formation, indicated by the presence of woven bone, in all cases. Four patients had essentially intact articular cartilage overlying the lesion, which was characterized by disruption of the trabecular architecture indicative of subchondral bone fracture. The other four patients had an isolated osteochondral defect with reparative tissue within the base of the defect. Only two knees had localized evidence of osteonecrosis, which appeared to be secondary to the fracture. This study provides pathologic evidence supporting the concept that subchondral fracture, and not osteonecrosis, is the major event in this rare complication following arthroscopy. Further investigation into the etiology of this condition is warranted.

New Advances in Liposuction Technology

Although suction-assisted liposuction under tumescent anesthesia remains the traditional method for body sculpting, newer technologies promise to increase efficiency, decrease surgeon fatigue, and minimize complication. Power-, ultrasound-, and laser-assisted devices are ideal in large volume cases and in areas of fibrous tissues as an adjunct to traditional liposuction. Although skepticism remains chemical lipolysis, more commonly termed mesotherapy or lipodissolve may be an alternative to surgical treatment of localized fat. This article reviews the recent advancements in the field of liposuction and the current literature which support their use.

Laser and novel light source treatments for psoriasis.

There are many treatment modalities for psoriasis including topical therapy, ultraviolet light therapy, systemic agents, and more recently the advent of the biologic agents. In addition, selective treatment using lasers and light sources that target the individual psoriatic plaques have also been employed. This article will highlight and review the employment of laser-assisted devices in the treatment of plaque psoriasis.

Characterization of optoacoustic surgical devices

Describes a measurement technique specially developed to characterize optoacoustic sources. The technique provides a convenient baseline for a comparison of different surgical ultrasonic systems utilizing optoacoustic and ultrasonic transducers. In addition, it provides a well-defined tool to optimize the performance of a variety of designs. Attention is focused on the laser-assisted devices in which appropriately delivered light energy is converted into acoustic shock wave. A meaningful comparison of such devices with other therapeutic equipment designed for a direct interaction with tissue requires knowledge of energy needed for a successful surgical treatment. It is demonstrated that knowledge of the key shock wave parameters allows the total acoustic energy associated with the shock wave to be determined. The procedure developed to calculate this energy is discussed and it is shown that the value of this energy can be conveniently used as an indicator of efficacy of an optoacoustic converter in a clinical environment. The influence of the performance of the polyvinylidene fluoride (PVDF) hydrophone probes on the measurement results was also analyzed. It was determined that when appropriately selected, the wide-band PVDF probes are well suited for characterization of the optoacoustic devices in the frequency range 1-100 MHz. The characterization procedure developed is applicable to surgical ultrasonic systems including conventional and laser-assisted phacoemulsifiers.