Modelling and Development of a Mechanical Eye for the Evaluation of Robotic Systems for Surgery.

Ophthalmic surgery, which addresses critical eye diseases such as retinal disorders, remains a formidable and arduous surgical pursuit. Nevertheless, with the advent of cutting-edge robotics and automation technology, significant advancement has been made in recent years to enhance the safety and efficacy of these procedures through meticulous research and development efforts. Ensuring the safe and effective execution of micro-surgical procedures requires stringent quality control measures, notably concerning evaluating and testing the devices utilized. During the development phase, these instruments must undergo extensive and continual evaluation by clinical practitioners to guarantee their safety and efficacy. Ideally, the test conditions should be identical to those of an actual operation. When testing robotic systems for ophthalmology, essential variables of the human eye, such as tissue properties and movement mechanisms, should be addressed. To minimize the discrepancy of tests and actual eye surgery conditions, in this paper, we propose a developed mechanical eye model to enable the realistic evaluation of ophthalmic surgical systems. After developing a virtual and physical model, the model was tested by an eye surgeon. The eye surgeon rated the model with four out of five possible points.Clinical relevance- This method ensures minimal discrepancy in verification of ophthalmic surgical devices by allowing the mechanical eye model to behave similar to the human eye, thus providing a realistic surgical procedure.

RCIT: A Robust Catadioptric-based Instrument 3D Tracking Method For Microsurgical Instruments In a Single-Camera System.

The field of robotic microsurgery and micro-manipulation has undergone a profound evolution in recent years, particularly with regard to the accuracy, precision, versatility, and dexterity. These advancements have the potential to revolutionize high-precision biomedical procedures, such as neurosurgery, vitreoretinal surgery, and cell micro-manipulation. However, a critical challenge in developing micron-precision robotic systems is accurately verifying the end-effector motion in 3D. Such verification is complicated due to environmental vibrations, inaccuracy of mechanical assembly, and other physical uncertainties. To overcome these challenges, this paper proposes a novel single-camera framework that utilizes mirrors with known geometric parameters to estimate the 3D position of the microsurgical instrument. Euclidean distance between reconstructed points by the algorithm and the robot movement recorded by the highly accurate encoders is considered an error. Our method exhibits an accurate estimation with the mean absolute error of 0.044 mm when tested on a 23G surgical cannula with a diameter of 0.640 mm and operates at a resolution of 4024 × 3036 at 30 frames per second.

Bioelectronics of The Cellular Cytoskeleton: Monitoring Cytoskeletal Conductance Variation for Sensing Drug Resistance.

Actin and microtubules form cellular cytoskeletal network, which mediates cell shape, motility and proliferation and are key targets for cancer therapy. Changes in cytoskeletal organization dramatically affect mechanical properties of the cells and correlate with proliferative capacity and invasiveness of cancer cells. Changes in the cytoskeletal network expectedly lead to altered nonmechanical material properties including electrical conductivity as well. Here we applied, for the first time, microtubule and actin based electrical measurement to monitor changes in the electrical properties of breast cancer cells upon administration of anti-tubulin and anti-actin drugs, respectively. Semiconductive behavior of microtubules and conductive behavior of actins presented different bioelectrical responses (in similar frequencies) of the cells treated by anti-tubulin with respect to anti-actin drugs. Doped silicon nanowires were applied as the electrodes due to their enhanced interactive surface and compatibility with electronic fabrication process. We found that treatment with Mebendazole (MBZ), a microtubule destabilizing agent, decreases electrical resistance while treatment with Paclitaxel (PTX), a microtubule stabilizing agent, leads to an increase in electrical resistance. In contrast, actin destabilizing agents, Cytochalasin D (CytD), and actin stabilizing agent, Phalloidin, lead to an increased and decreased electrical resistance, respectively. Our study thus provides proof-of-principle of the usage of determining the electrical function of cytoskeletal compartments in grading of cancer as well as drug resistance assays.

An electrochemical biosensor to distinguish between normal and cancer cells based on monitoring their acidosis using gold-coated silicon Nano-roughened electrode.

One of the most interesting fields of research in cancer diagnosis is tracing the relation between extracellular media and cancer progression. Detecting the secreting contents of the cells and translating these molecular identifications into label-free recognizable patterns would open new opportunities in cancer research. Electrochemical responses are in the range of most attractive sensing mechanisms especially in biochemical approaches. Perturbed ionic exchanges as a known biochemical function of cancer cells presented a strong correlation with the pH of the tumor microenvironment. Different ionic activities detected by an electrochemical bio-sensing system in the malignant and normal cells in the presence of acidic ambient were our main results presented in this research. Herein, silicon Nano-roughened substrate as a well-known electrochemical interface was applied in the construction of the biosensor. Viability rate as well as apoptotic factors involving in cancer progression were assessed by biochemical assays in normal (MCF10A) and cancer (MCF7 and MDA-MB468) breast cells. Our findings demonstrated that pH-based electrochemical responses were matched with the results obtained from the biological analyses of both normal and malignant cells. Induction of acidosis in the cells followed by monitoring their electrochemical responses would be a new trend in microenvironment based cancer investigation.

Tracing the pH dependent activation of autophagy in cancer cells by silicon nanowire-based impedance biosensor.

Monitoring the pH dependent behavior of normal and cancer cells by impedimetric biosensor based on Silicon Nanowires (SiNWs) was introduced to diagnose the invasive cancer cells. Autophagy as a biologically activated process in invasive cancer cells during acidosis, protect them from apoptosis in lower pH which presented in our work. As the autophagy is the only activated pathways which can maintain cellular proliferation in acidic media, responses of SiNW-ECIS in acidified cells could be correlated to the probability of autophagy activation in normal or cancer cells. In contrast, cell survival pathway wasn't activated in low-grade cancer cells which resulted in their acidosis. The measured electrical resistance of MCF10, MCF7, and MDA-MB468 cell lines, by SiNW sensor, in normal and acidic media were matched by the biological analyses of their vital functions. Invasive cancer cells exhibited increased electrical resistance in pH 6.5 meanwhile the two other types of the breast cells exhibited sharp (MCF10) and moderate (MCF7) decrease in their resistance. This procedure would be a new trend in microenvironment based cancer investigation.

Prevalence of Risky Behaviors and Related Factors among Students of Dezful.

Objective: There is a likelihood of risky behaviors such as drug abuse, risky sexual behavior, and adaptability issues in young ages. The present study aimed at investigating the prevalence of risky behaviors among students of Dezful University of Medical Sciences in 2014. Method: This was a descriptive-analytical cross sectional study, with a random sampling approach. Scale of measuring risky behaviors was used to measure the risky behaviors (high speed driving, maim, drug use, and sexual behaviors) and related factors. The mean, standard deviation, Chi-square tests, t tests, and ANOVA were used for data analysis. Results: The study was conducted on 150 (50%) female and 150 (50%) male students. Most of the participants aged 20 to 24 years. A statistically significant difference was obtained between the average scores of risky behaviors among female and male students (p˂0.05). The results of the present study revealed that the prevalence of risky behaviors, high speed driving, and drug consumption was different among the students of various study fields (p˂0.05). Conclusion: The prevalence of risky behaviors among students of Dezful University was relatively low, and the prevalence of these behaviors in female students was far less than in male students. Risky behaviors were associated with background variables, except for mother's occupation.

Silicon nanowire based biosensing platform for electrochemical sensing of Mebendazole drug activity on breast cancer cells.

Electrochemical approaches have played crucial roles in bio sensing because of their Potential in achieving sensitive, specific and low-cost detection of biomolecules and other bio evidences. Engineering the electrochemical sensing interface with nanomaterials tends to new generations of label-free biosensors with improved performances in terms of sensitive area and response signals. Here we applied Silicon Nanowire (SiNW) array electrodes (in an integrated architecture of working, counter and reference electrodes) grown by low pressure chemical vapor deposition (LPCVD) system with VLS procedure to electrochemically diagnose the presence of breast cancer cells as well as their response to anticancer drugs. Mebendazole (MBZ), has been used as antitubulin drug. It perturbs the anodic/cathodic response of the cell covered biosensor by releasing Cytochrome C in cytoplasm. Reduction of cytochrome C would change the ionic state of the cells monitored by SiNW biosensor. By applying well direct bioelectrical contacts with cancer cells, SiNWs can detect minor signal transduction and bio recognition events, resulting in precise biosensing. Our device detected the trace of MBZ drugs (with the concentration of 2nM) on electrochemical activity MCF-7 cells. Also, experimented biological analysis such as confocal and Flowcytometry assays confirmed the electrochemical results.

Nanoelectromechanical Chip (NELMEC) Combination of Nanoelectronics and Microfluidics to Diagnose Epithelial and Mesenchymal Circulating Tumor Cells from Leukocytes.

An integrated nano-electromechanical chip (NELMEC) has been developed for the label-free distinguishing of both epithelial and mesenchymal circulating tumor cells (ECTCs and MCTCs, respectively) from white blood cells (WBCs). This nanoelectronic microfluidic chip fabricated by silicon micromachining can trap large single cells (>12 µm) at the opening of the analysis microchannel arrays. The nature of the captured cells is detected using silicon nanograss (SiNG) electrodes patterned at the entrance of the channels. There is an observable difference between the membrane capacitance of the ECTCs and MCTCs and that of WBCs (measured using SiNG electrodes), which is the key indication for our diagnosis. The NELMEC chip not only solves the problem of the size overlap between CTCs and WBCs but also detects MCTCs without the need for any markers or tagging processes, which has been an important problem in previously reported CTC detection systems. The great conductivity of the gold-coated SiNG nanocontacts as well as their safe penetration into the membrane of captured cells, facilitate a precise and direct signal extraction to distinguish the type of captured cell. The results achieved from epithelial (MCF-7) and mesenchymal (MDA-MB231) breast cancer cells circulated in unprocessed blood suggest the significant applications for these diagnostic abilities of NELMEC.

Novel cryptosporidium genotypes in sporadic cryptosporidiosis cases: first report of human infections with a cervine genotype.

In this study, we genotyped parasites from the fecal specimens of sporadic cryptosporidiosis cases in British Columbia from 1995 to 1999. Genotyping was conducted by polymerase chain amplification of the internal transcribed spacer region, a hypervariable region in the 18S rRNA gene and the Cryptosporidium oocyst wall protein gene. Subsequent analysis was by restriction fragment length polymorphism and DNA sequencing. We identified two new Cryptosporidium genotypes in humans. One of these genotypes has been found recently in deer in New York state. The other genotype has not been identified in humans or animals. These results have important implications for drinking water quality strategies, especially for communities that obtain drinking water supplies from surface sources located in forested regions with deer populations.