Thermal optimization of robotic piezoelectric osteotomy motion in porcine trabecular bone.

Background: Piezoelectric osteotomy represents a potentially viable alternative to conventional techniques for preparing pilot holes for bone screws. However, piezoelectric osteotomes have demonstrated the potential to heat bone beyond 47 °C, which induces necrosis that could contribute to screw loosening, resulting in osteosynthetic material failure and pseudarthrosis. Thus, we sought to determine the working movements of a piezoelectric drill that resulted in the lowest maximum bone temperatures while ensuring that this optimal drilling motion resulted in temperatures below 47 °C.

Quantification metrics for telangiectasia using optical coherence tomography.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder that causes vascular malformations throughout the body. The most prevalent and accessible of these lesions are found throughout the skin and mucosa, and often rupture causing bleeding and anemia. A recent increase in potential HHT treatments have created a demand for quantitative metrics that can objectively measure the efficacy of new and developing treatments.

Real-time Gabor optical coherence tomographic angiography on human skin using CUDA GPU.

We recently proposed an optical coherence tomographic angiography (OCTA) algorithm, Gabor optical coherence tomographic angiography (GOCTA), which can extract microvascular signals from a spectral domain directly with lower computational complexity compared to other algorithms. In this manuscript, we combine a programmable swept source, an OCT complex signal detecting unit, and graphics process units (GPU) to achieve a real-time en-face GOCTA system for human skin microvascular imaging. The programmable swept source can balance the A-scan rate and the spectral tuning range; the polarization-modulation based complex signal detecting unit can double the imaging depth range, and the GPU can accelerate data processing.

Doppler optical coherence tomography for energy seal evaluation and comparison to visual evaluation (Erratum).

The erratum corrects a misspelled author surname.

Doppler optical coherence tomography for energy seal evaluation and comparison to visual evaluation.

Laser energy sealing systems have attracted much attention over the past decade given the general shift in surgical paradigm toward less invasive surgical approaches. Given this, it is paramount to have an objective method with which the quality of energy seals can be evaluated. Current methodologies used for this purpose can be problematic in the evaluation of small vessel seals.

Gabor optical coherence tomographic angiography (GOCTA) (Part II): theoretical basis of sensitivity improvement and optimization for processing speed.

We previously proposed a Gabor optical coherence tomography angiography (GOCTA) algorithm for spectral domain optical coherence tomography (SDOCT) to extract microvascular signals from spectral fringes directly, with speed improvement of 4 to 20 times over existing methods. In this manuscript, we explored the theoretical basis of GOCTA with comparison of experimental data using solid and liquid displacement sample targets, demonstrating that the majority of the GOCTA sensitivity advantage over speckle variance based techniques was in the small displacement range (< 10 ∼ 20 µm) of the moving target (such as red blood cells). We further normalized GOCTA signal by root-mean-square (RMS) of original fringes, achieving a more uniform image quality, especially at edges of blood vessels where slow flow could occur.

Optimization of laser osteotomy at 1064 nm using a graphite topical absorber and a nitrogen assist gas jet.

Laser ablation of bone for the purposes of osteotomy is not as well understood as ablation of homogeneous, non-biological materials such as metals and plastics. Ignition times and etch rate can vary during ablation of cortical bone. In this study, we propose the use of two techniques to optimize bone ablation at 1064nm using a coaxial nitrogen jet as an assist gas and topical application of graphite as a highly absorbing chromophore.

Buffer-averaging super-continuum source based spectral domain optical coherence tomography for high speed imaging.

In super-continuum (SC) source based spectral domain optical coherence tomography (SC-SDOCT), the stability of the power spectral density (PSD) has a significant impact on OCT system sensitivity and image signal to noise ratio (SNR). High speed imaging decreases the camera's exposure time, thus each A-scan contained fewer laser pulse excited SC wideband emissions, resulting in a decrease of SNR. In this manuscript, we present a buffer-averaging SC-SDOCT (BASC-SDOCT) to improve the system's performance without losing imaging speed, taking advantage of the excess output power from typical SC sources.

Smart laser osteotomy: integrating a pulsed 1064nm fiber laser into the sample arm of a fiber optic 1310nm OCT system for ablation monitoring.

Real-time depth metrology during material removal via laser ablation is useful in many forms of laser machining. Until now, coaxial optical coherence tomography (OCT) metrology was achieved by the coupling of an OCT imaging beam and ablating beams using a dichroic filter. We present an alternative design with all fiber delivery that is more suitable for surgical laser ablation applications.

2D MEMS-based high-speed beam-shifting technique for speckle noise reduction and flow rate measurement in optical coherence tomography.

In this manuscript, a two-dimensional (2D) micro-electro-mechanical system (MEMS)-based, high-speed beam-shifting spectral domain optical coherence tomography (MHB-SDOCT) is proposed for speckle noise reduction and absolute flow rate measurement. By combining a zigzag scanning protocol, the frame rates of 45.2 Hz for speckle reduction and 25.

Differential phase standard-deviation-based optical coherence tomographic angiography for human retinal imaging in vivo.

We present a differential phase standard-deviation (DPSD)-based optical coherence tomographic (OCT) angiography (OCTA) technique to calculate the angiography images of the human retina. The standard deviation was calculated along the depth direction on the differential phase image of two B-scans (from the same position, at different times) to contrast dynamic vascular signals. The performance of a DPSD was verified by both phantom and in vivo experiments.

Robotic laser osteotomy through penscriptive structured light visual servoing.

Purpose: Planning osteotomies is a task that surgeons do as part of standard surgical workflow. This task, however, becomes more difficult and less intuitive when a robot is tasked with performing the osteotomy. In this study, we aim to provide a new method for surgeons to allow for highly intuitive trajectory planning, similar to the way an attending surgeon would instruct a junior.

Beam-shifting technique for speckle reduction and flow rate measurement in optical coherence tomography.

In this Letter, we propose a beam-shifting optical coherence tomography scheme for speckle reduction and blood flow rate calculation, where variations of the speckle pattern and Doppler angle were generated by parallel shifting of the sample beam incident on the objective lens. The resultant optical coherent tomography images could then be averaged for speckle noise reduction and simultaneously analyzed for flow rate measurement. The performance of the proposed technique was verified by both phantom and in vivo experiments.

Comprehensive Evaluation of Soil Near Uranium Tailings, Beishan City, China.

To evaluate the impact of uranium tailings on soil composition and soil microbial, six soil samples at different distance from the uranium tailings (Beishan City, China) were collected for further analysis. Concentrations of radionuclides (U and Th), heavy metals (Mn, Cd, Cr, Ni, Zn, and Pb) and organochlorine pesticide were determined by ICP-MS and GC, they were significantly higher than those of the control. And the Average Well Color Development as well as the Shannon, the Evenness, and the Simpson index were calculated to evaluate the soil microbial diversity.

Gabor optical coherence tomographic angiography (GOCTA) (Part I): human retinal imaging .

Recently, parallel high A-line speed and wide field imaging for optical coherence tomography angiography (OCTA) has become more prevalent, resulting in a dramatic increase of data quantity which poses a challenge for real time imaging even for GPU in data processing. In this manuscript, we propose a new OCTA processing technique, Gabor optical coherence tomographic angiography (GOCTA), for label-free human retinal angiography imaging. In spectral domain optical coherence tomography (SDOCT), k-space resampling and Fourier transform (FFT) are required for the entire data set of interference fringes to calculate blood flow information in previous OCTA algorithms, which are computationally intensive.

High speed, wide velocity dynamic range Doppler optical coherence tomography (Part V): Optimal utilization of multi-beam scanning for Doppler and speckle variance microvascular imaging.

In this paper, a multi-beam scanning technique is proposed to optimize the microvascular images of human skin obtained with Doppler effect based methods and speckle variance processing. Flow phantom experiments were performed to investigate the suitability for combining multi-beam data to achieve enhanced microvascular imaging. To our surprise, the highly variable spot sizes (ranging from 13 to 77 μm) encountered in high numerical aperture multi-beam OCT system imaging the same target provided reasonably uniform Doppler variance and speckle variance responses as functions of flow velocity, which formed the basis for combining them to obtain better microvascular imaging without scanning penalty.

Differential standard deviation of log-scale intensity based optical coherence tomography angiography.

In this paper, a differential standard deviation of log-scale intensity (DSDLI) based optical coherence tomography angiography (OCTA) is presented for calculating microvascular images of human skin. The DSDLI algorithm calculates the variance in difference images of two consecutive log-scale intensity based structural images from the same position along depth direction to contrast blood flow. The en face microvascular images were then generated by calculating the standard deviation of the differential log-scale intensities within the specific depth range, resulting in an improvement in spatial resolution and SNR in microvascular images compared to speckle variance OCT and power intensity differential method.

Imaginary part-based correlation mapping optical coherence tomography for imaging of blood vessels in vivo.

We present an imaginary part-based correlation mapping optical coherence tomography (IMcmOCT) technique for in vivo blood vessels imaging. In the conventional correlation mapping optical coherence tomography (cmOCT) method, two adjacent frames of intensity-based structural images are correlated to extract blood flow information and the size of correlation window has to be increased to improve the signal-to-noise ratio of microcirculation maps, which may cause image blur and miss the small blood vessels. In the IMcmOCT method, the imaginary part of a depth-resolved complex analytic signal in two adjacent B-scans is correlated to reconstruct microcirculation maps.

[Culture conditions optimization and high cell density fermentation of recombinant bacteria producing heparinase II from Flavobacterium heparinum].

Heparinase II (Hep II) from Flavobacterium heparinum is an enzyme that could specifically cleave certain sequence of heparin and heparan sulfate. In this work, fermentation conditions of recombinant heparinase II (His-Hep II) producing bacteria were optimized, including initial induction time, inducer (IPTG) concentration, induction temperature and induction time. The optimum conditions were as follows: cultivating recombinant bacteria to exponential prophase under 37 degrees C, then adding IPTG to a final concentration of 0.

Post-infectious opsoclonus and reversible magnetic resonance imaging changes: a case report and review of the literatures.

Purpose: Opsoclonus is a rare neurological disorder in adult. The etiology of opsoclonus includes parainfectious, paraneoplastic, toxic, and metabolic disorders. We reported an old female with post-infectious opsoclonus who had a benign clinical course and reversible brain MRI lesions, and its review of the literature.

Renal vascular injury during percutaneous nephrolithotomy and migration of a double-J catheter fragment into pulmonary artery in the following nephrectomy--a case report.

A 60-year-old male underwent percutaneous nephrolithotomy (PCNL) for left renal stone at a community hospital. The surgery was, in general, unremarkable and a double-J ureteral catheter was placed before completion of surgery. Dyspnea, irritability, hypotension and flank pain developed in the recovery room.

Does a new videolaryngoscope (glidescope) provide better glottic exposure?

Background: The GlideScope (Saturn Biomedical Systems Inc, Burnaby, British Columbia, Canada) is a new videolaryngoscope designed as an alternative to the conventional laryngoscope. It was designed to facilitate glottic exposure during tracheal intubation. This study assessed the effectiveness of the GlideScope in providing glottic exposure.

Pneumothorax after central venous cannulation via the infraclavicular axillary vein--a case report.

It has ever been reported that central venous cannulation via the infraclavicular axillary vein (IAV) could cause pneumothorax. However, recently at our hospital, a 66-year-old female patient undergoing craniectomy for brain tumor sustained pneumothorax after cannulation of the IAV for intraoperate monitoring. The complication was not recognized until a postoperative chest X-ray had been taken.