Energy Dose Research Articles

The Effect of Power-Control and Irrigation Settings on Lesion Size during Radio-Frequency Ablation of Gastric Tissue.

Gastric ablation has recently emerged as a promising potential therapy for correcting bioelectrical dysrhythmias that underpin many gastrointestinal motility disorders. Despite similarities to well-developed cardiac radiofrequency (RF) ablation, gastric RF ablation is in its infancy and has thus far been limited to temperature-controlled, non-irrigated settings. The potential benefits of power-controlled and irrigated RF ablation have not been investigated in gastric tissue. In this study, RF ablation was performed in vivo in pigs ( n=5) using a range of power-control (10-30 W, 10s per point) and irrigation (2-5 ml/min) settings and compared to known temperature-controlled (65°C), non-irrigated settings. Excised tissue was stained with H&E. Lesion surface area was calculated and tissue damage was quantitatively ranked by visual assessment. The results demonstrated that irrigation allowed greater energy delivery to tissue with reduced interface temperatures compared to non-irrigated settings. Power settings above 10 W created lesions that extended through the full-thickness of the muscle layer, which suggests the parameter range that can now be used to correct gastric dysrhythmias. Clinical Relevance- This work presents the results of power-controlled, irrigated RF ablation settings applied to the in vivo porcine stomach. The relationships of both lesion area and depth to ablation dose provides an improved insight into which energy doses could provide a safe and effective therapeutic response.

Static and fatigue strength of laser-textured adhesive-bonded polyamide 66 (PA 66) joints

Nanosecond pulsed laser texturing has been performed as surface preparation for adhesive-bonded polyamide 66 (PA 66) joints. A Design-of-Experiments approach was firstly applied for optimization of laser parameters in terms of static joint strength, after which the fatigue strength of the best performing joints was determined. Quasi static and fatigue lap shear tests were performed on joints bonded with Teroson PU 9225. Laser texturing of PA 66 was found to be far less sensitive to heat accumulation in the hatch direction than in the laser scanning direction. Static average shear strength was generally found to increase with laser energy dose up to approximately 8–20 J/cm 2 , while no correlation was observed between the microscale surface roughness and static strength for low values of the former (S a < 2 μm). A shear strength of 11.60 MPa was achieved with a parallel-line scanning strategy and an average laser power of 3 W, hatch spacing of 50 μm and scanning velocity of 700 mm/s, representing a three-fold increase over standard primed joints. Laser-textured joints prepared with the same parameters exceeded the fatigue performance of atmospheric pressure plasma, mechanical abrasion and primer pre-treatments at both high and low maximum average cyclic shear stress, implying that laser texturing is an appropriate solution for improving bonding at high cyclic shear stress and prolonging the crack propagation phase at low cyclic shear stress.

Microdosimetric and radiobiological effects of gold nanoparticles at therapeutic radiation energies

Purpose The purpose of this study was to quantify the microscopic dose distribution surrounding gold nanoparticles (GNPs) irradiated at therapeutic energies and to measure the changes in cell survival in vitro caused by this dose enhancement. Methods The dose distributions from secondary electrons surrounding a single gold nanosphere and single gold nanocube of equal volume were both simulated using MCNP6. Dose enhancement factors (DEFs) in the 1 μm3 volume surrounding a GNP were calculated and compared between a nanosphere and nanocube and between 6 and 18 MV energies. This microscopic effect was explored further by experimentally measuring the cell survival of C-33a cervical cancer cells irradiated at 18 MV with varying doses of energy and concentrations of GNPs. Survival of cells receiving no irradiation, a 3 Gy dose, and a 6 Gy dose of 18 MV energy were determined for each concentration of GNPs. Results It was observed that the dose from electrons surrounding the gold nanocube surpasses that of a gold nanosphere up to a distance of 1.1 μm by 18.5% for the 18 MV energy spectrum and by 23.1% for the 6 MV spectrum. DEFs ranging from ∼2 to 8 were found, with the maximum DEF resulting from the case of the gold nanocube irradiated at 6 MV energy. Experimentally, for irradiation at 18 MV, incubating cells with 6 nM (0.10% gold by mass) GNPs produces an average 6.7% decrease in cell survival, and incubating cells with 9 nM (0.15% gold by mass) GNPs produces an average 14.6% decrease in cell survival, as compared to cells incubated and irradiated without GNPs. Conclusion We have successfully demonstrated the potential radiation dose enhancing effects in vitro and microdosimetrically from gold nanoparticles.

In vitro photodynamic treatment of Fusarium oxysporum conidia through the action of thiopyridinium and methoxypyridinium chlorins

Antimicrobial photodynamic inactivation (PDI) has been explored as an innovative therapeutic and phytosanitary approach because it can be used to inactivate microbial vegetative forms and spores, without significant development of resistance to photosensitization and collateral damage to host tissues. The objective of this study was to assess the photodynamic antifungal/sporicidal activity of quaternized chlorins (Chls) with thiopyridinium or methoxypyridinium substituents. Free-base and zinc(II) thiopyridinium or methoxypyridinium Chls (1a, 1b, 2a, and 2b, respectively) were prepared and tested on Fusarium oxysporum conidia. The PDI tests were conducted with photosensitizer (PS) concentrations of 100, 25, 15 and 5 µM, under white light exposure at an irradiance of 50 mW.cm−2, applied during 60 min (light dose of 180 J.cm−2). A high PDI efficiency, corresponding to inactivation to the detection limit, was observed with all the molecules. The free-base thiopyridinium chlorin 1a was the most effective PS, requiring the lowest concentration and the shortest irradiation time, for the complete inactivation of conidia (15 µM, 15 min, 45 J.cm−2). Complete inactivation was also achieved with the other chlorins but a higher concentration (100 µM) of PS and, in the case of chlorin 1b, a longer irradiation period (30 min, 90 J.cm−2), were required. Because of the low concentrations and small energy doses required to inactivate resistant biological forms such as fungal conidia, these chlorins can be regarded as potent antifungal photodynamic drugs.

Joining Photovoltaic Cell Connection Strips Using Ultra-Acoustic Wave - Resistive Hybrid Heating System

The manufacture of photovoltaic panels for the production of sustainable energy also involves the stage of electrical connection of the cells in the panel structure. This electrical connection is made by soldering of copper strips on the negative electrode of the cell. During the bonding process, due to the temperature of approximately 220-240°C at which the connecting strip is continuously heated, cracking processes of the upper layer of glass from the cell surface were identified. For this reason, it is necessary either to heat to lower temperatures, a solution that is not viable due to the melting temperature of the solder alloy which usually exceeds 210°C, or a different dosing of the heat flux. The solution proposed in the paper is to create a variable heat flux that allows the melting of the solder alloy, but at the same time to reduce the thermal load of the glass support layer. Through the proposed variant, the energy dosing is done with the help of a heating system consisting of two sources, an ultra-acoustic energy source and a classical resistive source. The resistive source provides an amount of energy to ensure a temperature in the range of 60-140°C, the difference to the melting point of the solder alloy being transferred locally by ultrasonic pulses. Research has highlighted the need to limit the range of values of the pressure of the circular sonotrode, which positively influences the mechanical stress of the photovoltaic cell, but also leads to a reduction in the joining speed. The dosing of the two components of the total energy, the one coming from the resistive source and the one coming from the ultra-acoustic vibration source is decisive for the efficiency of the joining process and for the quality of the soldered joint. Microscopic analyses revealed micro-cracks of the glass surface layer at forces higher than 100 N. Areas with lack of soldering for resistive heating at temperatures lower than 130oC were highlighted, the difference of 90-110°C being achieved by the contribution of ultra-acoustic energy.

ID:15988 Characterization of Different Energy Profiles of Differential Target Multiplexed™ Spinal Cord Stimulation

Differential Target Multiplexed (DTM™) spinal cord stimulation (SCS) has shown superior back pain relief to traditional SCS1 and has expanded the understanding of mechanism of action through preclinical studies demonstrating glial cell modulation.2,3 Along with the development of advanced stimulation patterns, energy dosing and waveform optimization for different environments are being explored. This study characterizes the efficacy and energy use of a stimulation pattern designed using the principles of DTM SCS with modifications to better understand energy requirements.

Optical properties of polymerization N-(3-methoxypropyl) acrylamide polymer gel dosimeters for radiotherapy

PurposeThe purpose of this paper is to evaluate the dosimetric properties of N-(3-methoxypropyl) acrylamide (NMPA) polymer gel dosimeter using UV-vis spectrophotometry as a simple and low-cost method.Design/methodology/approachThe gel samples have been irradiated to various doses using a medical linear accelerator with 6 MV beam energy. The optical density of un-irradiated and irradiated NMPA polymer gel dosimeters in terms of absorbance at 500 nm was investigated by UV-vis spectrophotometry.FindingsThe absorbance values of the gel samples were increased linearly with increasing dose in the dose range between 2 and 20 Gy. A remarkable improvement in the dose response was noticed after the addition of various concentrations of glycerol. The impact of dose rate, beam energy and the post-stability of the exposed gels was studied and found consistent with the previous study using nuclear magnetic resonance results (energy independent and dose rate independent, stable up to one week).Practical implicationsThe results of the independent experimental spectrophotometry and nuclear magnetic resonance analyses indicate that the NMPA polymer gel dosimeter has good and consistent dosimetric features for radiotherapy dosimetry.Originality/valueThe ionizing radiation-induced polymerization of gel samples leads to a change in the absorbance of the irradiated gel samples. This study introduces the first characterization of NMPA gel dosimeter by means of UV-vis spectrophotometer.

MR elastography is a good response parameter for microwave ablation liver tumors

ObjectivesTo determine the response of hepatic tissue to percutaneous microwave ablation (MWA) of liver tumors via MR elastography in a clinical setting using MRI and MR elastography. Methods51 Patients (28 m, 23f) underwent MWA of liver tumors (HCC: 20, metastasis: 31) and received MRI and MR elastography immediately before and 24 h after MWA.Retrospective analysis included pre- and post-ablative tumor extent, T1/T2 mapping and stiffness values as well as the duration and energy dose of the MWA session. ResultsTotal liver stiffness increased by 4.3% from 3.31 kPa to 3.45 kPa (p = 0.036). Total liver stiffness post-MWA significantly correlated with the duration of the MWA session (r = 0.369, p = 0.008).The higher the baseline tumor stiffness was, the more energy had to be applied in MWA (r = 0.391, p < 0.001) and the longer the duration of the session (r = 0.391, p = 0.007).Healthy parenchyma stiffness increased by 3.5% from 3.55 kPa to 3.68 kPa (p = 0.142) and was strongly influenced by the cumulative energy (r = 0.436, p < 0.001), the duration (r = 0.458, p < 0.001) and the energy intensity (r = 0.458, p < 0.001) of MWA.43 patients had a technically successful ablation result (margin ≥ 5 mm). Those with successful ablation had increased ablation margin stiffness (5.3 kPa vs. 4.6 kPa, p = 0.26) and had received higher ablation intensity than those with unsuccessful ablation (5.73 kJ/min vs. 5.03 kJ/min, p = 0.002). ConclusionAdditional MRE may be used before and after MWA to assess treatment response and collateral tissue damage after MWA. Baseline tumor stiffness helps finding the appropriate MWA parameters.

Monte Carlo computation of photon energy spectra in central axis of flattened and unflattened beams and doses in critical organs in a water phantom model of prostate radiotherapy

A thorough understanding of the energy spectra for clinical linear accelerators is essential in modern cancer treatment planning. We aimed to determine the radiation spectra and out-of-field doses in a water phantom under the conditions of prostate radiotherapy in beams with a flattening filter (FF) and without (FFF). Monte Carlo simulations were performed to determine the energy spectra and doses outside the irradiated volume. Doses were registered in locations corresponding to critical organs (kidneys, lungs, and thyroid) and the spectra was determined in the central axis (prostate gland). Simulations were conducted for 6 MV and 10 MV for FF and FFF beams. The out-of-field doses were calculated at selected points from the field edge for 6 MV photon beams (FF and FFF), and for 10 and 15 MV beams (FFF only). Compared to FF beams, we found that the mean energy for the photon spectra of FFF beams was lower. For 6 MV FF beams, the relative doses for the critical organs (kidneys, lungs and thyroid) were 0.7%, 1.2%, 0.6% versus 1.6%, 1.2%, 1.3% for the unflattened beams. For 10 MV FF beams, the out-of-field doses to the organs were 0.1%, 0.4% and 0.4% versus 0.4%, 0.2% and 0.3% with the FFF beam. FFF beams had a higher photon fluence, indicating less scattered radiation. Removal of the filter leads to lower doses in the areas surrounding the irradiated volumes, especially at large distances from the treatment field. These findings are consistent with previous reports, indicating that flattening filter free beams are likely to improve clinical outcomes. The reduction in scattered radiation lowers the probability of inducing second cancers.

Combined accelerated collagen crosslinking and sub-Bowman’s keratomileusis in high myopic eyes: a comparison between total ultraviolet energy dose

ABSTRACT Aim To compare the safety, efficacy, and predictability outcomes of combined sub-Bowman’s keratomileusis (thin flap laser in situ keratomileusis [LASIK]) and accelerated crosslinking (CXL) using two different irradiation durations. Methods A retrospective comparative study of patients with percent tissue altered ≥35%, undergoing simultaneous CXL during sub-Bowman’s keratomileusis were recruited. Following riboflavin application, they underwent ultraviolet-A (UVA) irradiation (18 mW/cm2) for either 2 min (total energy 2.16 J/cm2) or 3 min (total energy 3.24 J/cm2). Visual and refractive outcomes were compared between follow-up visits during the first year postoperatively. Demarcation line and endothelial cell count were evaluated, respectively, at 1 and 3 months postoperatively. Results The baseline characteristics were similar between the 40 eyes/patients treated using the 2-min protocol and the 33 eyes/patients treated with the 3-min protocol (p ≥ .114). Uncorrected distance visual acuity and corrected distance visual acuity were significantly better for eyes treated with the shorter irradiation protocol on Day 1 (p ≤ .030) and Month 1 (p ≤ .040) postoperatively; these differences diminished by Month 3 (p ≥ .070). Likewise, the efficacy index was higher during the first postoperative week for the 2-min protocol (p ≤ .043). At 1 year, the proportion of eye attaining within 0.5 D of target refraction was 80.0% and 84.8% for the 2-min and 3-min protocols, respectively (p = .590). The corresponding corneal stromal demarcation line depth and endothelial cell density changes were comparable between the two groups (p = .311 and 0.899, respectively). Conclusions A comparable volume of crosslinked corneal tissue can be achieved by using a shorter UVA irradiation duration. Additional duration of UVA irradiation could lead to delay in visual rehabilitation after simultaneous sub-Bowman’s keratomileusis and CXL.

He-Ne Laser Enhances Seed Germination and Salt Acclimation in Salvia officinalis Seedlings in a Manner Dependent on Phytochrome and H2O2.

In the current study the role of H2O2 in He-Ne laser-induced effects on seed germination and post-germinative performance of Salvia officinalis seedlings was assessed under both non-stress and saline conditions. Salinity had adverse impacts on seed germination and root length and decreased seed germination tolerance index. Seed priming with H2O2 and He-Ne laser impacted the seed germination and vigoration in a dose-dependent manner. The optimal effects were gathered by energy dose of 6J/cm2 laser and concentration of 5mM H2O2. These pre-treatments enhanced seed germination due to increasing contents of total soluble and reducing sugars and the amylase activity in seeds and improved seedling performance under saline and non-saline conditions. Furthermore, Phy B transcripts were upregulated, salt-accrued oxidative stress was mitigated, and the activities of POD and CAT increased in seedlings primed with H2O2 and laser. Interestingly, applying diphenyleneiodonium (DPI as an inhibitor of NADPH oxidase activity) and N, N-dimethyl thiourea (DMTU as a H2O2 scavenger) arrested the upregulation of phy B gene and abolished stimulatory impact of laser priming on the aforementioned attributes under both non-stress and saline conditions. These novel findings suggest that H2O2 as a downstream signal modulates the impacts of He-Ne laser on seed germination, seedling performance and salt acclimation in sage seedlings, and likely phy B also is involved in these responses.

Exploring the Role and Mechanism of Adipose Derived Mesenchymal Stem Cells on Reversal of Pigmentation Model Effects.

Interventions for extrinsic aging can be implemented, but these must address photoaging, which is the primary cause of extrinsic aging. Pigmentation due to photoaging depends on the duration and intensity of sun exposure. This study investigated the relationship between adipose-derived mesenchymal stem cells (ASCs) and photoaging pigmentation, and the underlying mechanism of action by establishing a photoaging pigmentation model using various treatments and exposure options in a guinea pigs. The energy dose of each UVB irradiation was 120 mJ/cm2 and the total dose of irradiation was 360 mJ/cm2. After successfully establishing the photoaging model, ASCs (1×106) in an balanced salt solution (0.9 ml), balanced salt solution (0.9 ml), and bFGF (9 μg) mixed with an balanced salt solution (0.9 ml) were injected intradermally in ten guinea pigs. ELISA, macroscopic skin and histological observations, and Masson-Fontana staining were done. At 2 and 4 weeks post-injection, noticeable changes were observed. Guinea pigs receiving ASCs injections displayed significantly lower visible skin scores while the melanin content continued to decrease. Somewhat improved histopathological morphology, including epidermal thinning, dermal thickening, and little inflammatory cell infiltration was observedimmediately after and up to 4 weeks of ASCs injection. Melanocortin 1 receptor (MC1R) and alpha-melanocyte test hormone (alpha-MSH) levels reduced significantly, and basic fibroblast growth factor (bFGF) levels increased significantly immediately after and up to 4 weeks of ASCs injection. The MC1R and alpha-MSH levels reduced significantly immediately after and up to 4 weeks of bFGF injection. Briefly, intradermal ASCs injection can notably eliminate pigmentation in a guinea pig photoaging pigmentation model. This may be related to the fact that bFGF secreted by ASCs lowers MC1R and alpha-MSH levels, blocks the cAMP signalling pathway, and inhibits melanin synthesis. This finding may present new options for treating photoaging pigmentation.Level of Evidence: N/A.

Development of a dosimetry system for therapeutic X-rays using a flexible amorphous silicon thin-film solar cell with a scintillator screen.

To evaluate the dosimetric characteristics and applications of a dosimetry system composed of a flexible amorphous silicon thin-film solar cell and scintillator screen (STFSC-SS) for therapeutic X-rays. The real-time dosimetry system was composed of a flexible a-Si thin-film solar cell (0.2-mm thick), a scintillator screen to increase its efficiency, and an electrometer to measure the generated charge. The dosimetric characteristics of the developed system were evaluated including its energy dependence, dose linearity, and angular dependence. Calibration factors for the signal measured by the system and absorbed dose-to-water were obtained by setting reference conditions. The application and correction accuracy of the developed system were evaluated by comparing the absorbed dose-to-water measured using a patient treatment beam with that measured using the ion chamber. The responses of STFSC-SS to energy, field size, depth, and source-to-surface distance (SSD) were more dependent on measurement conditions than were the responses of the ion chamber, although the former dependence was due to the scintillator screen, not the solar cell. The signals of STFSC-SS were also dependent on dose rate, while the responses of solar cell alone and scintillator screen were not dependent on dose rate. The scintillator screen reduced the output of solar cell at 6 and 15 MV by 0.60 and 0.55%, respectively. The different absorbed dose-to-water measured using STFSC-SS for patient treatment beam differed by 0.4% compared to those measured using the ionization chamber. The uncertainties of the developed system for 6 and 15 MV photon beams were 1.8 and 1.7%, respectively, confirming the accuracy and applicability of this system. The thin-film solar cell-based detector developed in this study can accurately measure absorbed dose-to-water. The increased signal resulting from the use of the scintillator screen is advantageous for measuring low doses and stable signal output. In addition, this system is flexible, making it applicable to curved surfaces, such as a patient's body, and is cost-effective.

Features of skin cancer that has developed in the area of scarring: literature review

For many decades, in the literature there has been a discussion about the role of skin scars in the development of tumors. Despite this, the distinctive features of their formation and pathogenetic mechanisms remain not fully revealed. The princ-i ples of malignant tumors’ development of healthy and pathologically altered skin remain unresolved. There are conflicting data on the influence of climatogeographic and social factors on the development of skin cancer. It has been established that ultraviolet irradiation plays an important role in the development of malignant skin neoplasms. Intensive insolation is the cause of the development of pathological changes in the skin and vascular tissue. Perhaps one of the probable patho-genic factors is the influence of damaging doses of solar energy. On the skin structure in Central Asian countries, where skin cancer occupies the leading rank among all malignant tumors. The results of treatment in skin cancer that has developed in the area of scarring of various origins – mechanical, traumatic injuries, or chemical, thermal burns – remain disappointing. The development of relapses and metastases in the nearby anatomic structures after treatment worsen the quality of life in the patients; dictate the selection of adequate methodological approaches to this group of patients.

Experimental verification of real-time gamma-ray energy spectrum and dose monitor

The purpose of this study is to develop a portable monitor that can measure the energy spectrum and dose of gamma-rays simultaneously in real time for the benefit of medical staff who must work in clinical radiation environments. For this purpose, we have developed a prototype monitor using a CsI (Tl) scintillator combined with a multi-pixel photon counter (MPPC). For real-time measurement, we employed an improved sequential Bayesian estimation (k-α method) to convert the measured pulse height spectrum into an energy spectrum. Then we confirmed that reconstruction of the energy spectrum and dose estimation could simultaneously be carried out in real time by the k-α method in a radiation field composed of mixed standard gamma-ray sources. In this study, we carried out measurements in a background gamma-ray field to confirm applicability of the prototype monitor to the weakest type of radiation field. In addition, we conducted measurements in front of a nuclear fuel storage room (∼2 μSv/h) in the authors’ laboratory to evaluate practicality of the monitor for measuring fields with a complex energy spectrum. As a result, it was found that the dose could be estimated in about 20 s after start of measurements even in the background field. For the energy spectrum, it was instantly reconstructed within 60 s in front of the fuel storage room. On the other hand, it could successfully be estimated within 10 min in the background gamma-ray field. Currently, the convergence of the energy spectrum is determined visually from time dependent change of the spectrum and dose. As a next step, we will attempt to develop a more quantitative procedure for determining the convergence.

Application of pulsed light technology for fruits and vegetables disinfection: A review.

Non-thermal technologies can maintain fruit and vegetable products quality better than traditional thermal processing. Pulsed light (PL) is a non-thermal method for microbial inactivation (vegetative cells and spores) in fruits and vegetables. The PL treatment involves the application of intense and short-duration pulses of broad spectrum wavelengths ranging from UV to near-infrared (100-1100nm). This review summarized application of PL technology to control microbial contamination and increasing shelf-life of some fruits and vegetables including apple, blueberries, grape, orange, strawberries, carrot, lettuce, spinach, and tomato. The microbial inactivation in very short treatment times, low energy used by this system, flexibility for solid or liquid samples, few residual compounds and no synthetic chemicals that cause environmental pollution or harm humans, is benefits of PL technique. The efficiency of PL disinfection is closely associated with the input voltage, fluence (energy dose), composition of the emitted light spectrum, number of lamps, the distance between samples and light source, and frequency and number of applied pulses. The PL treatments control pathogenic and spoilage microorganisms, so it facilitates the growth and development of the starter microorganisms affecting product quality.

Bactericidal Efficacy of High Irradiance Ultraviolet A Photoactivation of Riboflavin Versus Standard Corneal Cross-Linking Protocol In Vitro.

The purpose of this study was to compare the efficacy of high ultraviolet A (UVA) irradiance photoactivation of riboflavin (vitamin B2) versus the standard corneal cross-linking protocol on bacterial viability. Methicillin-sensitive Staphylococcus aureus (MSSA) Newman strain and methicillin-resistant multidrug-resistant S. aureus (MDR-MRSA) USA300, CA409, CA127, GA656, and NY315 strains were exposed to a UVA energy dose of 5.4 to 6 J/cm 2 by 2 high irradiance regimens: A) 30 mW/cm 2 for 3 minutes and B) 10 mW/cm 2 for 10 minutes with B2 0.1%. Control groups included B2/UVA alone, CA409 exposed to standard B2 0.1% + UVA (3 mW/cm 2 for 30 minutes), and an untreated sample. Cell viability was assessed. Triplicate values were obtained. The Mann-Whitney test and Student t test were used for statistical analysis. There was no difference comparing the median bacterial load (log CFU/mL) of the untreated samples versus regimen A: Newman P = 0.7, CA409 P = 0.3, USA300 P = 0.5, CA127 P = 0.6, GA656 P = 0.1, and NY315 P = 0.2 ( P ≥ 0.1); and B: Newman P = 0.1, CA409 P = 0.3, USA300 P = 0.4, CA127 P = 0.6, GA656 P = 0.1, and NY315 P = 0.3 ( P ≥ 0.1). Standard regimen killed 100% of CA409. Photoactivation of B2 by high UVA irradiance does not seem to be effective for bacterial eradication in this study.

Hygienic and environmental problems of oil and gas production on the offshore shelf

The article discusses the results of research carried out within the framework of the industry program of Rospotrebnadzor “Hygienic scientific justification for minimizing risks to the health of the population of Russia” for 2016–2020 (p. 2. 16). During the development of oil and gas fields of the shelf in the waters of the Northern, etc. In addition to climatic conditions, dangerous and harmful factors of the production environment have a significant impact on working conditions: intense industrial noise, general and local vibration, insufficient lighting, contamination of the working area with dangerous chemicals and gases. Often, oil and gas in wells are under high pressure, which creates a threat of explosive emissions and fires. Among the unfavorable factors, the leading place is also occupied by noise, which affects workers during the entire shift from 7 to 30 or more days continuously. The noise sources are power plants and working mechanisms. Sound pressure levels in workplaces reach 72–107 dBA, in cabins 52–67 dBA. The equivalent daily sound levels are 71–102 dBA, and the total doses of acoustic energy affecting personnel exceed the permissible requirements by tens of times. In order to ensure the implementation of industrial and environmental control during the development of oil and gas fields on the offshore shelf, the main parameters, sources and mechanisms of marine water pollution have been determined. The sanitary and hygienic characteristics of the quality of sea water, ways and mechanisms of monitoring the state of sea waters are given. The analysis and updating of a number of existing regulatory and methodological documents in the field of ensuring the sanitary and epidemiological well-being of the population and the safety of environmental objects, including the draft SanPiN 2.2.3... “Sanitary rules and regulations for drilling rigs and structures used in the development of offshore hydrocarbon deposits” has been prepared.

Characterization of Miniature Probes for Cryosurgery, Thermal Ablation, and Irreversible Electroporation on Small Animals

AbstractFocal therapies, including cryosurgery, thermal ablation, and irreversible electroporation (IRE) are widely used in the treatment of cancer and other diseases, aimed at exposing cancer cells to extreme physical conditions leading to cell death. Focal ablation outcomes are extensively studied in small animal preclinical models, such as mice; however, robust engineering characterization of these treatments is largely lacking, due in a large part to the lack of control in applying clinical devices (cm scale) to mouse tumors (mm scale). To address this issue, miniaturized probes are designed and built for controlled application of cryosurgery, thermal ablation, and IRE and their performance is evaluated using ex vivo porcine liver tissue and an in vivo MC‐38 tumor model. These experimental results are compared to simulated conditions in heat transfer (cryosurgery and thermal ablation) and electrical (IRE) models. Agreements of physical quantities between measurement and modeling are shown for all the focal therapy cases. The in vivo outcome is further correlated with tumor growth delay. The characterization improves the understanding of the energy dose to create tissue damage, therefore enables to better understand outcomes in preclinical studies and predict and optimize the outcome of future clinical procedures.

Parenteral Nutrition Total Energy Dosing and Risk for Central Line–Associated Bloodstream Infection: A Case-Control Study

Background: Central line–associated bloodstream infection (CLABSI) is a complication of central venous access devices used for parenteral nutrition (PN). PN overfeeding is associated with increased adverse effects; however, whether risk for CLABSI is influenced by PN dosing is uncertain. Objective: The purpose of the study was to assess differences in CLABSI risk associated with recommended total energy dosing in hospitalized adult patients receiving PN. Methods: A case-control study was conducted in a single United States Veterans Health Administration health system to assess the potential CLABSI risk factor of weight-based PN kilocalorie dosing. Hospitalized adult patients who developed CLABSI while receiving PN were identified and compared to a control group of patients who did not develop CLABSI. The exposures evaluated were overfeeding, defined as greater than 30 kcal/kg/day, and underfeeding, defined as less than 20 kcal/kg/day. Results: Twenty-nine cases of CLABSI were identified and compared with 274 controls. Odds of CLABSI were significantly higher in patients receiving greater than 30 kcal/kg/day (OR, 3.63; 95% CI, 1.55-8.48; P < .01). No significant difference in odds was found for patients receiving less than 20 kcal/kg/day (OR, .74; 95% CI, 0.21-2.57; P = .63). Conclusion: Increased risk for CLABSI in hospitalized adult patients receiving PN was found to be associated with overfeeding, but not underfeeding. These results may aid clinicians in the management of patients requiring PN and in the generation of hypothesis for future investigations.