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1.
Environ Sci Pollut Res Int ; 31(17): 25356-25372, 2024 Apr.
Article En | MEDLINE | ID: mdl-38472576

Currently, the majority of the country has moved to renewable energy sources for electricity generation, and power companies are concentrating their efforts on renewable resources. Solar, wind, hydropower, and biomass are examples of renewable resources; of these, due to a lack of non-renewable resources, the solar industry is expanding. All year long, solar electricity is available, and it creates a calm, quiet atmosphere. The majority of large and small companies, as well as individual consumers, have shifted to PV solar cells for electricity generation. A trustworthy and precise simulation design of a photovoltaic system prior to installation is required to predict a photovoltaic system's performance. The current research aims to build models for solar PV systems with one, two, and three diodes and determine which model is most appropriate for each environmental circumstance to forecast performance accurately. By contrasting the experimental data of solar panel with simulated results of single-, double-, and triple-diode models, this study examines the accuracy of each model. These models' comparative performance study has been done using the MATLAB/Simulink, taking into account the influence of changing model parameters and the performance of the models under varying climatic circumstances. These models, despite their simplicity, are quite sensitive and react to even a little change in temperature and irradiance. Under conditions of low solar irradiance or shading conditions, three-diode photovoltaic models are shown to be more accurate. We can forecast the power output of solar photovoltaic systems under changeable input circumstances by understanding the I-V curves with the help of the performance assessment of the models used in this work.


Solar Energy , Sunlight , Computer Simulation , Wind , Temperature , Electricity
2.
Med Eng Phys ; 125: 104133, 2024 03.
Article En | MEDLINE | ID: mdl-38508806

This work reports a novel POC diagnostic technique to identify the cancerous liver cell lines by designing a Source-Extended (SE) Tunnel Field Effect Transistor (TFET) having a Single-Gate (SG) with Single-Metal (SM) and Dual-Metal (DM) structure. The proposed structures have been equipped with nanocavities by trenching the gate oxide layer where the needle biopsy obtained liver sample has been immobilized. The detection is based on the difference in drain current and the ratio of the proposed device's ON and OFF state currents, which has been evaluated by obtaining the sensitivities. The cancerous and non-cancerous liver cell lines possess different dielectric properties in high frequencies ranging from 100 MHz to 5 GHz, affecting the cavity region's effective capacitances. The change in the dielectric constant of the specimen at 900 MHz has been considered which results in the change in device drain current and device performance. Various parameters of the device, like the adhesive layer in the cavity region, the material of the gate, the length of the cavities, and the orientation of the cavities, have been modified to observe the performance. The total work has been done in the simulation environment, which includes the study considering the different proportions of cancerous and non-cancerous cells in a particular specimen. A comparative analysis has been made between the performance of the proposed SM and DM gate structure. The proposed detection method has been compared with the existing methods reported in the literature. The proposed method can be considered a novel technique and can be implemented as a point of care (POC) diagnostic to detect whether the specimen liver cell line is cancerous.


Liver Neoplasms , Point-of-Care Systems , Humans , Torso , Liver Neoplasms/diagnosis , Biopsy, Needle
3.
Clin J Sport Med ; 34(2): 91-96, 2024 Mar 01.
Article En | MEDLINE | ID: mdl-37389465

OBJECTIVE: To establish whether time to exercise cessation using the Buffalo Concussion Treadmill Test (BCTT) protocol can be used as a prognostic indicator of recovery after sport-related mild traumatic brain injury (SR-mTBI). DESIGN: Retrospective analysis of prospectively collected data. SETTING: Specialist Concussion Clinic. PARTICIPANTS: Three hundred and twenty one patients presenting between 2017 and 2019 who underwent BCTT for SR-mTBI. INTERVENTIONS: Participants who remained symptomatic at a 2-week follow-up appointment after SR-mTBI underwent BCTT to develop a progressive subsymptom threshold exercise program with fortnightly follow-up until clinical recovery. MAIN OUTCOME MEASURES: Clinical recovery was the primary outcome measure. RESULTS: A total of 321 participants were eligible to participate in this study (mean age 22.94% and 46% female). The BCTT test duration was divided into 4-minute intervals and those who completed full 20 minutes. There was higher probability of clinical recovery in those who finished the entire 20-minute BCTT protocol compared with those who managed 17-<20 minutes (Hazard Ratio, HR 0.57), 13 to 16 minutes (HR 0.53), 9 to 12 minutes (HR 0.6), 5 to 8 minutes (HR 0.4), and 1 to 4 minutes (HR 0.7), respectively. Those seen earlier after injury ( P = 0.009), male patients ( P = 0.116), younger patients ( P = 0.0003), and those with physiological or cervical dominant ( P = 0.416) symptom clusters were more likely to achieve clinical recovery. Fifty percent of those who completed the full BCTT protocol achieved clinical recovery at day 19 post-injury. CONCLUSIONS: The group completing full 20 minutes of BCTT achieved clinical recovery more quickly than those who did not complete full BCTT.


Athletic Injuries , Brain Concussion , Humans , Male , Female , Young Adult , Adult , Brain Concussion/diagnosis , Athletic Injuries/diagnosis , Prognosis , Retrospective Studies , Exercise Test/methods
4.
Appl Opt ; 62(36): 9523-9535, 2023 Dec 20.
Article En | MEDLINE | ID: mdl-38108777

In this paper, a FMCW-based cooperative 2×2 MIMO photonic radar system using heterodyne detection is presented. The proposed system consists of two separate sensor nodes that use a linear frequency modulated continuous wave signal, which allows simultaneous monostatic and bistatic radar measurement, where the target range and angle of arrival information are extracted. The additional bistatic information enhances the target detection and estimation capabilities with improved accuracy. This accuracy in practicality is affected by the laser phase noise, which degrades the overall system performance. Here, the analytical laser phase noise model for the MIMO system is derived and implemented to analyze its impact on the ranging accuracy of the proposed system. Under the impact of standard white Gaussian laser phase noise assumption, the monostatic and bistatic response of the detected signal is measured and compared using statistics of measurement error. Further, the signal-to-noise ratio and SSB laser phase noise of the monostatic and bistatic response are measured and compared at different target ranges. At last, the phase-noise-limited ranging accuracy of the system is evaluated and analyzed. The concept shown in this work paves the way for advanced photonic radar system applications such as modern radar systems, electronic warfare systems, metrology, and automotive vehicle radar with multiperspective coherent detection.

5.
J Biomed Opt ; 28(8): 087001, 2023 08.
Article En | MEDLINE | ID: mdl-37533956

Significance: Diabetes is a prevalent disease worldwide that can cause severe health problems. Accurate blood glucose detection is crucial for diabetes management, and noninvasive methods can be more convenient and less painful than traditional finger-prick methods. Aim: We aim to report a noncontact speckle-based blood glucose measurement system that utilizes artificial intelligence (AI) data processing to improve glucose detection accuracy. The study also explores the influence of an alternating current (AC) induced magnetic field on the sensitivity and selectivity of blood glucose detection. Approach: The proposed blood glucose sensor consists of a digital camera, an AC-generated magnetic field source, a laser illuminating the subject's finger, and a computer. A magnetic field is applied to the finger, and a camera records the speckle patterns generated by the laser light reflected from the finger. The acquired video data are preprocessed for machine learning (ML) and deep neural networks (DNNs) to classify blood plasma glucose levels. The standard finger-prick method is used as a reference for blood glucose level classification. Results: The study found that the noncontact speckle-based blood glucose measurement system with AI data processing allows for the detection of blood plasma glucose levels with high accuracy. The ML approach gives better results than the tested DNNs as the proposed data preprocessing is highly selective and efficient. Conclusions: The proposed noncontact blood glucose sensing mechanism utilizing AI data processing and a magnetic field can potentially improve glucose detection accuracy, making it more convenient and less painful for patients. The system also allows for inexpensive blood glucose sensing mechanisms and fast blood glucose screening. The results suggest that noninvasive methods can improve blood glucose detection accuracy, which can have significant implications for diabetes management. Investigations involving representative sampling data, including subjects of different ages, gender, race, and health status, could allow for further improvement.


Artificial Intelligence , Diabetes Mellitus , Humans , Blood Glucose , Neural Networks, Computer , Machine Learning , Diabetes Mellitus/diagnostic imaging
6.
J Biomed Opt ; 27(9)2022 09.
Article En | MEDLINE | ID: mdl-36059076

SIGNIFICANCE: The ability to perform frequent non-invasive monitoring of glucose in the bloodstream is very applicable for diabetic patients. AIM: We experimentally verified a non-invasive multimode fiber-based technique for sensing glucose concentration in the bloodstream by extracting and analyzing the collected speckle patterns. APPROACH: The proposed sensor consists of a laser source, digital camera, computer, multimode fiber, and alternating current (AC) generated magnetic field source. The experiments were performed using a covered (with cladding and jacket) and uncovered (without cladding and jacket) multimode fiber touching the skin under a magnetic field and without it. The subject's finger was placed on a fiber to detect the glucose concentration. The method tracks variations in the speckle patterns due to light interaction with the bloodstream affected by blood glucose. RESULTS: The uncovered fiber placed above the finger under the AC magnetic field (150 G) at 140 Hz was found to have a lock-in amplification role, improving the glucose detection precision. The application of the machine learning algorithms in preprocessed speckle pattern data increase glucose measurement accuracy. Classification of the speckle patterns for uncovered fiber under the AC magnetic field allowed for detection of the blood glucose with high accuracy for all tested subjects compared with other tested configurations. CONCLUSIONS: The proposed technique was theoretically analyzed and experimentally validated in this work. The results were verified by the traditional finger-prick method, which was also used for classification as a conventional reference marker of blood glucose levels. The main goal of the proposed technique was to develop a non-invasive, low-cost blood glucose sensor for easy use by humans.


Blood Glucose , Fiber Optic Technology , Algorithms , Humans , Lasers , Machine Learning
7.
Cryobiology ; 106: 148-156, 2022 06.
Article En | MEDLINE | ID: mdl-35305994

The present study proposes a novel approach to treat skin cancer. It is an amalgamation of two techniques; (i) Cryospray in which necrosis is achieved through local application of liquid nitrogen spray on lesions (occurring on superficial skin) and (ii) Transdermal Drug Delivery systems (TDDS) in which drugs are administered through the superficial skin. It focuses on increasing the cryoablation through the administration of nanoparticles in the skin. Biodegradable Magnesium Oxide (MgO) nanoparticles are selected to make nano-phantom. TEM and XRD results reveal the crystalline nature of MgO nanoparticle with particle diameter 10-40 nm. A comparative study of cryoablation is carried out between the nano-phantom and the normal-phantom while spraying liquid nitrogen through a commercial 0.8 mm diameter single hole nozzle. Quantitative and qualitative improvements in cryoablation are observed due to the presence of nanoparticle. Necrotic zone in nano-phantom is twice larger than in the normal-phantom up to an axial depth of 2 mm from the centre of spray for the same spraying distance. Minimum spraying distance for nano-phantom is estimated to be 13 mm. Among the three spraying distances selected for the study, it has been observed that cryoablation decreases as the spraying distance increases. The proposed approach can be used to enhance the scope of cryospray in the treatment of larger lesions like Squamous cell carcinoma, keloids etc. without incorporating the device modifications.


Cryosurgery , Nanoparticles , Cryopreservation/methods , Cryosurgery/methods , Magnesium Oxide , Nitrogen , Skin Temperature
8.
Middle East J Dig Dis ; 14(1): 77-84, 2022 Jan.
Article En | MEDLINE | ID: mdl-36619726

BACKGROUND: The increasing prevalence of antibiotic-resistant strains of Helicobacter pylori (H. pylori) led to reduced success with traditional H. pylori treatments. This warrants further evaluation of other treatment options. One such treatment regimen of interest is nitazoxanide containing regimen. In this study, we evaluated the efficacy of the addition of nitazoxanide to clarithromycin-based triple therapy in patients with H. pylori infection. METHODS: In this single-center prospective observational trial, patients with H. pylori infection were treated with a regimen comprising of nitazoxanide 1000 mg, amoxicillin 2000 mg, clarithromycin 1000 mg, and esomeprazole 80 mg per day (NACE regimen) for14 days. Eradication of H. pylori infection was assessed 4 weeks after completion of therapy by using stool antigen assay. Treatment compliance and adverse effects were also evaluated. RESULTS: Out of 111 patients who entered into the study for final analysis, H. pylori eradication was achieved in 93.7% (104 out of 111) patients in per-protocol analysis and 90.4% (104 out of 115) patients in intention to treat analysis. The treatment regimen was well tolerated. CONCLUSION: The addition of nitazoxanide to standard clarithromycin-based triple therapy effectively eradicates H. pylori infection. This regimen is safe and well tolerated.

9.
Cryobiology ; 98: 201-209, 2021 02.
Article En | MEDLINE | ID: mdl-33171196

Smaller spray zone of single-hole nozzle (SHN) constrains cryospray as a treatment method suitable for lesions having diameter larger than 15 mm on the skin surface. The present study is an attempt to resolve this issue, through the improvement in conventional technique of spraying liquid nitrogen on cancerous lesion. A multi-hole nozzle (MHN) with 5 holes is fabricated to demarcate the variation in outcome when cryogen is sprayed through customised MHN instead of conventional SHN. Special emphasis is placed on reducing the number of sitting required for completion of treatment and increasing the feasibility of cryospray process for larger lesions. Commercial SHN having a hole diameter of 0.8 mm is selected to compare results with the customised MHN having 5 holes of 0.8 mm diameter (4 holes are arranged in a circle of radius 2 mm around the central hole). Single freeze-thaw cycle is carried out to spray liquid nitrogen on tissue mimicking gel. Temperature profile accessed through infrared images advocates that lethal area formed through application of MHN is twice larger than the lethal area formed through the application of SHN on the surface of gel for same spraying distance (z). Thermocouples placed at various locations strengthen the fact that higher cooling rate (CR) corresponding to MHN ensures 15 mm spread of necrotic zone from the centre of spray (CS) and up to a depth of 2 mm from the gel surface while in case of SHN, it is limited to the vicinity of CS. On the basis of observations made through thermal images and digital images, it can be said that the ratio of lateral spread to penetration depth of ice ball remains almost same for SHN and MHN. However, the lateral spread of ice ball formed through the application of MHN is twice larger than SHN while the axial depth of ice ball does not record such increment. This reflects that MHN provides more destruction to superficial skin than SHN. Among the three spraying distances selected (i.e. z = 13 mm, 18 mm and 23 mm), the most optimised spraying distance (z) for MHN is also explored in this study. It has been found that cryoablation is not inversely proportional to the spraying distance. Spraying distance of z = 18 mm provided the most optimised result in terms of cryoablation.


Cryopreservation , Cryosurgery , Cryopreservation/methods , Freezing , Skin Temperature , Temperature
10.
Cryobiology ; 96: 197-206, 2020 10.
Article En | MEDLINE | ID: mdl-32712073

Present study deals with improvement in conventional technique of spraying liquid nitrogen on cancerous lesions to improve its efficacy. It is an attempt to demarcate the variation in outcome when cryogen is sprayed through customised multi-hole nozzle (MHN). Influence of mass flow rate on cryoablation while varying the number of holes in MHNs is analysed experimentally. Another section of study focuses on the impact of the rate of evaporation of cryogen when margin among the holes is changed. Total 6 MHNs are fabricated while changing their geometrical parameters. Single freeze-thaw cycle is carried out to spray liquid nitrogen on tissue mimicking gel with a spraying distance of 18 mm. Temperature profile captured through infrared images advocates that lethal area formed through the application of MHNs with 5 holes is larger than MHNs with 4 holes on the surface of gel. It reflects the influence of central hole on necrosis. In order to necrotize lesion through freezing, the most desired cooling rate (CR) varies from 50∘C/min to 200∘C/min. It is achieved up to a depth of 2 mm below the gel surface and in a radius of 10 mm from the centre of spray (CS) for all MHNs, except 4C. Most optimised margin in terms of cryoablation is also estimated in the study. MHN with 1.5 mm margin provides the most optimised results in terms of cryoablation when MHNs with the central hole are considered while MHN with 1 mm margin provides most optimised result when MHNs without central hole are considered. On the basis of observations made through thermal images it can be said that multiple freezing fronts are not observed on the gel surface which aids in the formation of lone giant ice ball. This provides an extra edge to the treatment methodology because alteration in the dimensions of necrotic zone can be made by changing the duration of spray. Larger lateral spread of necrotic zone will also reduce the number of sittings required for the treatment of larger lesions.


Cryopreservation , Cryosurgery , Cryopreservation/methods , Freezing , Skin Temperature , Temperature
11.
Chempluschem ; 85(5): 910-920, 2020 May.
Article En | MEDLINE | ID: mdl-32401425

In this work, two symmetrical donor-acceptor-donor (D-A-D) type benzoselenadiazole (BSeD)-based π-conjugated molecules were synthesized and employed as an active switching layer for non-volatile data storage applications. BSeD-based derivatives with different donor units attached through common vinylene linkers showed different electrical and optical properties. 4,7-Di((E)-styryl)benzo[c][2,1,3]selenadiazole (DSBSeD) and 4,7-bis((E)-4-methoxystyryl)benzo[c][2,1,3]selenadiazole (DMBSeD) are sandwiched between gallium-doped ZnO (GZO) and metal aluminum electrodes respectively through solution-processed spin-coating method. The solution-processed nanofibrous switching layer containing the DMBSeD-based memory device showed reliable memory characteristics in terms of write and erase operations with low SET voltage than the random-aggregated DSBSeD-based device. The nanofibrous molecular morphology of switching layer overcomes the interfacial hole transport energy barrier at the interface of the DMBSeD thin-film and the bottom GZO electrode. The memory device GZO/DMBSeD/Al based on nanofibrous switching layers shows switching characteristics at compliance current of 10 mA with Vset =0.79 V and Vreset =-0.55 V. This work will be beneficial for the rational design of advanced next-generation organic memory devices by controlling the nanostructured morphology of active organic switching layer for enhanced charge-transfer phenomenon.

12.
Australas Phys Eng Sci Med ; 42(2): 453-464, 2019 Jun.
Article En | MEDLINE | ID: mdl-30838526

The main purpose of the study is to establish correlations for the ablation volume and the ice front as a function of the spray parameters. The ablation volume and the ice front depend upon the nozzle diameter, spraying distance and the freeze duration (spray parameters). The estimation of the ablation volume using the spray parameters shall be useful in surgical practice to ablate the different sizes of tumours. Liquid nitrogen spray cooling is carried out with 0.8 mm, 0.6 mm and 0.4 mm nozzle diameters. The spraying distance is maintained at 9 mm, 18 mm and 27 mm. The spray cooling is carried out for a single freeze-thaw cycle where freezing and thawing consist of 120 s and 130 s duration respectively. A two-dimensional heat flow equation with phase change is considered for the numerical study. The numerically calculated transient temperature (2 mm and 5 mm from the gel surface) and ice front values show confirmatory results with the experimentally measured data. Correlations are obtained to determine the ablation volume (- 50 °C and - 25 °C isothermal surfaces) and ice front (axial and lateral) with a goodness of fit [Formula: see text] 95%. The nozzle diameter has a greater impact on the ablation volume as compared to the spraying distance during 120 s of freezing. The nozzle diameter of 0.8 mm, 0.6 mm and 0.4 mm can be effectively used for cryotherapy with spraying distance up to 27 mm, 18 mm and 9 mm respectively.


Cryotherapy , Skin Neoplasms/therapy , Tumor Burden , Phantoms, Imaging , Temperature
13.
ACS Appl Mater Interfaces ; 10(6): 5464-5474, 2018 Feb 14.
Article En | MEDLINE | ID: mdl-29356500

The use of the high free-electron concentration in heavily doped semiconductor enables the realization of plasmons. We report a novel approach to generate plasmons in Ga:ZnO (GZO) thin films in the wide spectral range of ∼1.87-10.04 eV. In the grown GZO thin films, dual-ion beam sputtering (DIBS) instigated plasmon is observed because of the formation of different metallic nanoclusters are reported. Moreover, formation of the nanoclusters and generation of plasmons are verified by field emission scanning electron microscope, electron energy loss spectra obtained by ultraviolet photoelectron spectroscopy, and spectroscopic ellipsometry analysis. Moreover, the calculation of valence bulk, valence surface, and particle plasmon resonance energies are performed, and indexing of each plasmon peaks with corresponding plasmon energy peak of the different nanoclusters is carried out. Further, the use of DIBS-instigated plasmon-enhanced GZO can be a novel mean to improve the performance of photovoltaic, photodetector, and sensing devices.

14.
Nanotechnology ; 29(5): 055203, 2018 Feb 02.
Article En | MEDLINE | ID: mdl-29231180

Single synaptic device with inherent learning and memory functions is demonstrated based on a forming-free amorphous Y2O3 (yttria) memristor fabricated by dual ion beam sputtering system. Synaptic functions such as nonlinear transmission characteristics, long-term plasticity, short-term plasticity and 'learning behavior (LB)' are achieved using a single synaptic device based on cost-effective metal-insulator-semiconductor (MIS) structure. An 'LB' function is demonstrated, for the first time in the literature, for a yttria based memristor, which bears a resemblance to certain memory functions of biological systems. The realization of key synaptic functions in a cost-effective MIS structure would promote much cheaper synapse for artificial neural network.

15.
Appl Opt ; 55(22): 5830-9, 2016 Aug 01.
Article En | MEDLINE | ID: mdl-27505360

A novel technique of photonic generation of millimeter-waves beyond the presently reported 120 GHz and with a wider tunability (∼240 GHz) is proposed and demonstrated through a simulation experiment. The scheme consists of generating 24 times the frequency of a conventional low frequency microwave source using a combination of a LiNbO3 Mach-Zehnder modulator and four-wave mixing in a semiconductor optical amplifier. The filtering of a high frequency sideband and the suppression of a carrier are achieved by incorporating an optical band pass and fiber Bragg grating filters, respectively. Next, the spectral purity of the generated millimeter-wave parameters is evaluated after propagation through a conventional fiber of different lengths by digitally modulating it at 2.5 Gbps and generating an eye diagram. The constraints on the selection of the frequency of the millimeter-wave and length of fiber are discussed. The present method of millimeter-wave generation and distribution will find applications in photonic up/down conversion, phase-array antennas, photonic sensors, radars, and terahertz applications.

16.
Math Biosci ; 266: 85-92, 2015 Aug.
Article En | MEDLINE | ID: mdl-26092609

Ample evidence has shown that morphine influences learning and memory and thereby causing addiction. Various studies have shown that it decreases the inhibitory GABAergic synaptic transmission (LTPGABA) via the soluble guanylate cyclase (sGC) and nitric oxide (NO) pathway. But still it is unclear on how does morphine inhibit the sGC-NO pathway. In this study, we show the mechanism of LTPGABA inhibition by morphine with the help of a mathematical model. A two step model of sGC activation is used, where morphine inhibits NO during the first step and consequently blocks sGC activation. Here, morphine binding on µ-opioid receptors blocks the binding of retrogradely travelling NO to sGC and hence its activation. As a result, LTPGABA is not produced which increases the chances of addiction manifold. Alongwith the mechanism, the dependence of morphine inhibition on major parameters such as morphine dissociation, morphine concentration, NO removal & rate of inhibition and its effect on addiction is also shown.


Models, Theoretical , Morphine Dependence/metabolism , Morphine/pharmacology , Narcotics/pharmacology , Nitric Oxide/metabolism , Soluble Guanylyl Cyclase/metabolism , Synaptic Transmission/drug effects , Ventral Tegmental Area/metabolism , Animals , Humans
17.
Cryobiology ; 70(1): 53-9, 2015 Feb.
Article En | MEDLINE | ID: mdl-25526964

The effect of initial Me2SO concentration (cgi) inside the cell lines on the optimal cooling rate is studied using a well established water transport model. A correlation formula is proposed for the determination of optimal cooling rate of freezing biological systems which depends on the cell activation energy, reference membrane permeability, initial Me2SO concentration, and the cell geometrical parameters. Here, the optimal cooling rate is defined as the highest cooling rate for which amount of trapped water inside the cell is equal to 5% of the initial cell water content at an end temperature of -40 °C. It is found that the optimal cooling rate varies linearly with the reference membrane permeability and the ratio of surface area for water transport to the initial volume of intracellular water. The developed correlation is valid for cell activation energy between 20 and 80 kcal/mole and initial Me2SO concentration between 0.1 and 1.3M. It has been observed that the optimal cooling rate does not follow a single trend for the studied initial concentration of Me2SO. However, three regions are identified within which, the variation is almost similar; the three regions are: 0.1 M ≤ cgi ≤ 0.7, 0.7 M ≤ cgi ≤ 0.9, and 0.9 M ≤ cgi ≤ 1.3M. It has been shown that the predicted optimal cooling rate is in a very good agreement with the published experimental/numerical prediction.


Cell Membrane Permeability/drug effects , Cryopreservation/methods , Cryoprotective Agents/pharmacology , Dimethyl Sulfoxide/pharmacology , Semen Preservation/methods , Algorithms , Animals , Biological Transport , Cell Membrane/physiology , Freezing , Humans , Male , Mice , Models, Theoretical , Ostreidae , Spermatozoa/drug effects , Temperature , Water/metabolism
18.
Cryobiology ; 67(2): 201-13, 2013 Oct.
Article En | MEDLINE | ID: mdl-23867079

Freezing tumours and ablating it using cryosurgery is becoming a popular surgical procedure for treatment of carcinomas. In order to improve the efficiency of the cryosurgical procedure different approaches have been implemented till now, e.g., injecting high thermal conductivity fluid inside the tumour, low latent heat fluids inside the tumour prior to cryosurgery etc. These techniques improve the cryosurgical process to some extent but lack in minimising the damage to the surrounding healthy tissues. In this study, a novel concept is proposed which advocates the use of solutions with specific thermophysical properties around the interface of tumour. Numerical modelling has been done to determine the location of the ice fronts in the presence of this solution around the boundary of the tumour. It is noticed that in the presence of solution layer, owing to its distinct thermophysical properties like low thermal conductivity, not only the cellular destruction is enhanced but also the damage to the surrounding healthy tissue is minimised. Further, results indicate that this strategy leads to a faster ablation rate reducing the surgical time immensely. Also, an optimal offset, the minimum distance between the tip of cryoprobe and the boundary of the tumour, is identified for a given tumour radius with a given active length which gives maximum tumour necrosis in less time. This optimal offset which has been identified for each case will help the surgeons in proper planning of cryosurgery and improving the effectiveness of this technique greatly, making it a better treatment modality than its counterparts in many ways. It is also observed that for a 2 mm increase in activelength of the cryoprobe, the decrease in optimal offset is approximately 1 mm, i.e. optimal offset decreases linearly with an increase in the activelength for a given radius of the tumour. Also, for tumour with different radii, ranging between 10 mm to 15 mm, with same active length, the time taken for complete ablation by the larger tumour is nearly 2.7 times the time taken by the smaller one for every 2.5 mm increase in the tumour radius.


Cryosurgery/methods , Neoplasms/surgery , Algorithms , Computer Simulation , Cryosurgery/instrumentation , Equipment Design , Humans , Models, Biological
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