Non-thermal Method Research Articles

Effect of ozonation parameters on nutritional and microbiological quality of sugarcane juice

AbstractSugarcane juice is susceptible to rapid spoilage and quality deterioration owing to browning of the juice and fermentation. To address this issue, ozonation of the juice has been attempted in this work. For optimization of ozonation process, response surface methodology based on full factorial design with control variables of gas flow rates (3, 6.5, and 10 L/min); ozone concentration (10, 20, and 30% wt/wt); and exposure time (5, 12.5, and 20 min) were employed. Physicochemical and microbiological indices were affected significantly by the gas flow rate irrespective of other two independent variables. Regression analysis showed that the predicted quadratic model fitted well with the experimental data and was significant (p < .05) with coefficient of determination (R2) for all responses >.9. Significant reductions in nutritional parameters, such as polyphenol content (13.5%), flavonoid content (22.5%), ascorbic acid content (81.46%), and antioxidant capacity (30%) were observed after ozonation. However, the treatment resulted in 67.8% inactivation of polyphenol oxidase enzyme and 3.72 log reduction in total plate count. Sensory analysis revealed that the treated juice was acceptable in terms of sensory properties. Thus, the ozone treatment was proved effective in enzyme inactivation and microbial destruction that offered enhanced anti‐browning and antimicrobial properties to the sugarcane juice.Practical applicationsSugarcane juice is susceptible to rapid spoilage and quality deterioration owing to the browning and fermentation resulting in its short shelf life. It is an extremely perishable product that loses its marketability because of processing problems. Considering the nutritional importance of this juice, it can be emerged as an energy drink if adequately treated. Consumer demands for minimally processed health foods have further encouraged the research related to techniques for processing of fruit juices. Ozone processing is one such potential nonthermal method which can enable extension of shelf life of sugarcane juice, yet retaining its freshness and organoleptic properties that in turn aid in the growth of juice processing industry.

Extraction of 11-Keto-β -Boswellic Acid from Indian Olibanum by Contemporary Extraction Modes: Optimization and Validation of HPTLC.

Boswellic acids are the main constituents of Boswellia serrata gum. These comprise of four pentacyclic triterpenes, 11-keto-β-boswellic acid (KBA) being one of them. Comparing the extraction efficiency of KBA through microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) followed by optimizing the extraction process using response surface methodology (RSM) and validation of HPTLC. UAE and MAE of KBA were carried out employing methanol as an extracting solvent. To figure out the better mode of extraction, single factorial experiments were conducted for further optimization. Design expert software was used for optimization purposes where solvent to drug ratio, extraction temperature and extraction time were taken as input variables. Quantification of KBA in each extract was done through High-Performance Thin Layer Chromatography (HPTLC), and the method was validated as per International Council for Harmonization (ICH) guidelines. UAE stood out to be a better mode of extraction for KBA. Solvent to drug ratio of 20.42 mL/gram, extraction temperature of 44.01°C and extraction time of 11.54 minutes were established as optimum conditions, which yielded 8.44%w/w of KBA. Regarding HPTLC, the Rf value of KBA was measured, and the correlation coefficient was calculated from the standard curve. Accuracy, precision and recovery were found within limits. From this study, it was concluded that a non-thermal method is a better choice of extraction for KBA. All the input variables significantly affected KBA content, which was confirmed by model fitting. Moreover, the HPTLC method was developed for the quantification of KBA, which was found to be accurate, reliable and highly sensitive.

Effects of ultrasound treatment on the starch properties and oil absorption of potato chips

As a non-thermal processing method, the ultrasound treatment prior to the frying process has been demonstrated with great potential in reducing the oil absorption of fried food. This research aimed to evaluate the effect of ultrasound pretreatment on starch properties, water status, pore characteristics, and the oil absorption of potato slices. Ultrasound probe set with two power (360 W and 600 W) at the frequency of 20 kHz for 60 min was applied to perform the pretreatments. The results showed that ultrasound pretreatment led to the surface erosion of starch granules and higher power made the structure of starch disorganized. Moreover, the fraction of bound water and immobilized water were changed after ultrasonic pretreatment. Pores with the minor diameters (0.4–3 μm and 7–12 μm) were formed after ultrasound pretreatment. The penetrated surface oil (PSO) content, and structure oil (STO) content were reduced by 27.31% and 22.25% respectively with lower power ultrasound pretreatment. As the ultrasound power increased, the surface oil (SO) content and PSO content increased by 25.34% and 12.89% respectively, while STO content decreased by 38.05%. By using ultrasonic prior to frying, the quality of potato chips has been greatly improved.

Abstract 2221: Combining irreversible electroporation with TLR7 and CD40 agonists confers systemic anti-tumor immunity in a murine pancreatic cancer model

Abstract Introduction: Pancreatic Cancer (PC) has a highly immunosuppressive microenvironment with a low mutational burden and has so far been resistant to immunotherapy. Irreversible electroporation (IRE) is a non-thermal method of inducing tumor cell death, without damage to adjacent blood vessels, that is being used clinically for selected patients with locally advanced PC. Despite local control rates greater than 90%, most IRE patients develop distant recurrence, emphasizing the need for better methods to treat micrometastatic disease. Using an immunocompetent mouse model of PC, we have previously shown that IRE induces complete regression in 25-33% of subcutaneous tumors, and complete responders are protected from a tumor rechallenge. However, IRE alone did not produce significant therapeutic immunity (abscopal effects) against concomitant distant tumors. We hypothesized that combination of IRE with innate immune stimulators would also enhance the adaptive immune response. Methods: We used a cell line generated from a genetically engineered (KPC) mouse establish bilateral flank tumors. The “primary” tumor was treated with IRE alone or in combination with local delivery of a toll-like receptor 7 (TLR7) agonist (1V270) and CD40 agonistic antibody (CD40Ab). 15 parameter procartaplex (Thermo) was used for cytokine analysis and RNA-Seq was performed using an Illumina MiSeq 1000 platform with total RNA from excised tumor all on day 7 post procedure. Results: We observed complete regression in 8/10 tumors treated with the combination (Combo) of IRE, 1V270 and CD40Ab compared to 3/10 in IRE alone. However, the combo was much more effective than IRE alone at inducing regression of the untreated secondary flank tumor, including complete regression of 7/10 untreated tumors. CD40Ab alone had minimal effect on local or secondary tumor growth. Analysis of systemic cytokines using multiplex analysis showed 112 fold increase in IFNy levels in plasma with the Combo compared to untreated mice (P<0.001) and a 39 fold increase compared to IRE alone (P<0.001). Other factors of Th1 response such as IP-10 and IL12-P70 were also significantly (P<0.001) higher in the Combo group compared to IRE alone along with TNFa (elevated 3.2 fold vs IRE). RNA-Seq of the whole tumor followed by gene set enrichment analysis showed significant elevation in Type II interferon, (P<0.0001), IL2 (P<0.0001), and apoptosis (P=0.0001) pathways in the Combo group. Both IRE alone and the Combo group complete responders were protected from tumor growth after immediate rechallenge (14 days) and delayed rechallenge (180 days). However, flow cytometric analysis of the splenocytes revealed that the combo group had more CD44+CD62L+CD8+ central memory T-cells (16%) in contrast to IRE alone (11%). Conclusion: These data suggest that local delivery of CD40Ab and TLR7 agonists augment the systemic immune effects of IRE and have the potential to improve the overall survival of patients undergoing IRE for locally advanced PC by reducing distant recurrence. Citation Format: Jayanth Surya Narayanan Shankara Narayanan, Diego Vicente, Partha Ray, Thomas Whisenant, Rebekah White. Combining irreversible electroporation with TLR7 and CD40 agonists confers systemic anti-tumor immunity in a murine pancreatic cancer model [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2221.

Three-year results of a randomized controlled trial comparing mechanochemical and thermal ablation in the treatment of insufficient great saphenous veins

ObjectiveMechanochemical ablation (MOCA) is a nonthermal nontumescent method of treating saphenous vein insufficiency. The feasibility and short-term results of MOCA are good, but its long-term results are unknown. A randomized study was performed to compare MOCA with endovenous laser ablation (EVLA) and radiofrequency ablation (RFA) in the setting of unilateral great saphenous vein (GSV) insufficiency. MethodsVenous outpatient clinic patients with varicose veins (CEAP class C2-C4) caused by GSV insufficiency were invited to participate in the study; in total, 132 patients met the inclusion criteria and were willing to participate. Patients were randomized to treatment (2:1:1 for MOCA, EVLA, and RFA, respectively). The state of the GSV with duplex Doppler ultrasound examination and the disease-specific quality of life were assessed at 1 month, 1 year, and 3 years after the treatment. ResultsSome patients declined to continue in the study after randomization; in total, 117 patients underwent treatment. At 3 years, the occlusion rate was significantly lower with MOCA than with either EVLA or RFA (82% vs 100%; P = .005). Quality of life was similar between the groups. In the MOCA group, GSVs that were larger than 7 mm in diameter preoperatively were more likely to recanalize during the follow-up period. The partial recanalizations of proximal GSV observed at 1 year progressed during the follow-up. ConclusionsMOCA is a feasible treatment option in an outpatient setting, but its technical success rates are inferior compared with endovenous thermal ablation. Its use in large-caliber veins should be considered carefully.

Degradation of Deoxynivalenol by Atmospheric-Pressure Cold Plasma and Sequential Treatments with Heat and UV Light

Atmospheric-pressure cold plasma (ACP) technology is a novel non-thermal method with the potential to be used as a post-harvest treatment for mycotoxin mitigation. Deoxynivalenol (DON), a mycotoxin that occurs predominantly in grains, is a threat to human health and to the agricultural economy worldwide. In this study, the effects of the treatment time, and the presence of ACN/water on the DON degradation efficacy during ACP treatment were evaluated. ACP treatment for 5 min resulted in 100% degradation in DON in solution (20 μg/ml ACN/water (20/80, v/v)), while the DON degradation was only 75.9% after 60 min of treatment, in dry condition (2 μg DON). Thin-layer chromatography (TLC) and Fourier transform infrared spectroscopy (FTIR) were used to determine structural changes in DON after ACP treatment. FTIR analysis revealed major changes in DON functional groups after ACP treatment in solution form. Sequential treatments involving ACP and heat treatment at 80 °C and ACP and light-emitting diode (LED) treatments were tested to reduce DON concentrations in dry form. Heat treatment alone was not effective in reducing DON, while sequential treatment of 30-min ACP with 25-min heat reduced DON by 64.6%, which was not significantly different from the DON reduction (63%) by 30-min ACP alone. LED treatments for 30 and 60 min reduced DON concentrations by 10.7% and 36.7%, respectively; while sequential treatment of 30-min ACP with 30-min LED reduced DON by 68.8%. This study shows that the ACP technology has the potential to degrade DON.

Electroporation-Based Treatments in Urology.

The observation that an application of a pulsed electric field (PEF) resulted in an increased permeability of the cell membrane has led to the discovery of the phenomenon called electroporation (EP). Depending on the parameters of the electric current and cell features, electroporation can be either reversible or irreversible. The irreversible electroporation (IRE) found its use in urology as a non-thermal ablative method of prostate and renal cancer. As its mechanism is based on the permeabilization of cell membrane phospholipids, IRE (as well as other treatments based on EP) provides selectivity sparing extracellular proteins and matrix. Reversible EP enables the transfer of genes, drugs, and small exogenous proteins. In clinical practice, reversible EP can locally increase the uptake of cytotoxic drugs such as cisplatin and bleomycin. This approach is known as electrochemotherapy (ECT). Few in vivo and in vitro trials of ECT have been performed on urological cancers. EP provides the possibility of transmission of genes across the cell membrane. As the protocols of gene electrotransfer (GET) over the last few years have improved, EP has become a well-known technique for non-viral cell transfection. GET involves DNA transfection directly to the cancer or the host skin and muscle tissue. Among urological cancers, the GET of several plasmids encoding prostate cancer antigens has been investigated in clinical trials. This review brings into discussion the underlying mechanism of EP and an overview of the latest progress and development perspectives of EP-based treatments in urology.

Effect of rotating peanuts on aflatoxin detoxification by ultraviolet C light and irradiation uniformity evaluated by AgCl-based dosimeter

Ultraviolet irradiation (UV) has been used as a non-thermal processing method for food disinfection. In disinfecting solid foods such as peanuts, UV irradiation could be shaded or attenuated with increased distance, resulting in non-uniform dosage distribution. An affordable, rapid, and feasible method for measuring and improving irradiance distribution, however, is unavailable for detoxifying peanuts. In this study, a method was developed for rapidly quantifying UV dosage distribution on peanuts in a UV disinfection process. The darkening of the UV indicator, AgCl, was linearly proportional to the UV dosage from 0 to 120 mJ/cm2 delivered on peanuts. The uniformity of UV dosage distribution was described by measuring the color change of UV indicator at four points on two orthogonal axes of each peanut kernel. The UV indicator coated peanuts were then rotated in a customized cylindrical chamber at different speeds. A rotation speed with more uniform UV dosage distribution was determined and applied to an aflatoxin detoxification process. The results demonstrate that the UV uniformity was significantly improved when peanuts were rotated at 11 rpm in the cylindrical chamber. Furthermore, after irradiating with 2.3 mW/cm2 UV-C for 2 h, the aflatoxin B1 degradation rate increased from 60.8 ± 15.3 pmol g−1h−1 to 75.0 ± 10.9 pmol g−1h−1 in the peanuts rotated at 11 rpm, compared to those that were not rotated.

Terahertz Wave Accelerates DNA Unwinding: A Molecular Dynamics Simulation Study.

Unwinding the double helix of the DNA molecule is the basis of gene duplication and gene editing, and the acceleration of this unwinding process is crucial to the rapid detection of genetic information. Based on the unwinding of six-base-pair DNA duplexes, we demonstrate that a terahertz stimulus at a characteristic frequency (44.0 THz) can serve as an efficient, nonthermal, and long-range method to accelerate the unwinding process of DNA duplexes. The average speed of the unwinding process increased by 20 times at least, and its temperature was significantly reduced. The mechanism was revealed to be the resonance between the terahertz stimulus and the vibration of purine connected by the weak hydrogen bond and the consequent break in hydrogen bond connections between these base pairs. Our findings potentially provide a promising application of terahertz technology for the rapid detection of nucleic acids, biomedicine, and therapy.

Effect of gamma irradiation on physico‐mechanical and structural properties of basil seed mucilage‐chitosan films containingZiziphora clinopodioidesessential oil and MgO nanoparticles for rainbow trout packaging

In the present study, it was aimed to evaluate the effect of gamma irradiation (0, 2.5, and 5 kGy) on physico-mechanical and structural properties of basil seed mucilage-chitosan-based films containing Ziziphora clinopodioides essential oil (ZEO: 0%, 1%, and 2%) and magnesium oxide nanoparticles (MgO: 0%, 0.1%, and 0.2%), and their application on trout fillet´s shelf-life during refrigerated storage for 18 days. The irradiated films under the cobalt-60 source at 5 kGy dose had better tensile strength as well as lower swelling index and water vapor transmission rate compared with other prepared films. Therefore, all films selected to package trout fillets were irradiated at 5 kGy dose. Fillets packaged with films containing ZEO 2% + MgO 0.2% and ZEO 2% + MgO 0.1% had the lowest microbial population (total viable count, psychrotrophic count, Pseudomonas spp., P. fluorescens, H2S producing bacteria, and Enterobacteriaceae) and chemical changes (total volatile base nitrogen content and peroxide value) (p < .05). Practical applications Active packaging has been introduced to increase the shelf-life of fresh fishery products during refrigerated storage. Gamma irradiation is a nonthermal method of food preservation and has recently received great interest in betterment of the physico-mechanical properties of packaging biopolymers. Our findings indicated that irradiation at 2.5 and 5 kGy doses can be used as a tool for improvement of the property of basil seed mucilage-chitosan-based films. The designated films containing Ziziphora clinopodioides essential oil (1% and 2%) and MgO nanoparticles (0.1% and 0.2%) could improve the shelf-life of trout fillets up to 18 days during refrigerated storage condition.

The effect of high voltage electric shock on the quality attribute of carp fish (Cyprinus carpio) meat

Carp is one of the commercial freshwater fish and requires good preservation to maintain the quality of the meat. The non-thermal food preservation method that is still being developed is by using a high voltage electric shock or often called Pulse Electric Field (PEF). The research on the treatment of electric shock using PEF on carp meat has been done. This study aimed to measure the effect of high voltage electric shock on the quality of the carp fish meat. Fresh carp meat fillets were given exposure to electric shock (30 kV, 60 kV, and 90 kV; frequency 50 Hz; pulse width 0.4 s; 600 pulses) when compared with untreated as a control. The data of log total plate count (TPC) and other quality attributes were analyzed by ANOVA and advanced test with Honesly Significance Different (HSD), while non-parametric data were analyzed using Kruskal-Wallis and Mann-Whitney test. The result showed that in untreated meat fish, the log of TPC is higher than threated meat and significantly different (P < 0.05) at untreated with the treated samples. The electric shock treatment caused temperature increment from 3.3+0.7°C until 5.6+1.3°C but not significantly different between samples. Moisture content decreased significantly due to high voltage electric shock treatment. pH values ranged from 6.46+0.20 to 6.62+0.23 and were not significantly different between treatment. Meat with electric shock treated showed significantly different (P<0.05) on weight loss but not in cooking loss. There are no significant differences in hedonic value except tenderness with 60kV. On the microstructure, the treated meat looks more porous than untreated meat. It is indicating that high voltage electric shock processing was effective in the maintenance of carp meat qualities.

Surface modifications caused by cold atmospheric plasma sterilization treatment

Inactivation of microorganisms on sensitive surfaces by cold atmospheric plasma is one major application in the field of plasma medicine because it provides a simple and effective way to sterilize heat-sensitive materials. Therefore, one has to know whether plasma treatment affects the treated surfaces, and thus causes long-term surface modifications. In this contribution, the effect of cold atmospheric Surface micro-discharge (SMD) plasma on different materials and its sporicidal behavior was investigated.Hence, different material samples (stainless steel, different polymers and glass) were plasma-treated for 16 hours, simulating multiple plasma treatments using an SMD plasma device. Afterwards, the material samples were analyzed using surface analysis methods such as laser microscopy, contact angle measurements and x-ray photo-electron spectroscopy. Furthermore, the device was used to investigate the behavior of Bacillus atrophaeus endospores inoculated on material samples at different treatment times.The interaction results for plasma-treated endospores show, that a log reduction of the spore count between 4.3 and 6.2 can be achieved within 15 min of plasma treatment. Besides, the surface analysis revealed, that there were three different types of reactions the probed materials showed to plasma treatment, ranging from no changes to shifts of the materials’ free surface energies and oxidation.As a consequence, it should be taken into account that even though cold atmospheric plasma treatment is a non-thermal method to inactivate microorganisms on heat-sensitive materials, it still affects surface properties of the treated materials. Therefore, the focus of future work must be a further classification of plasma-caused material modifications.

Applications of Pulsed Light Decontamination Technology in Food Processing: An Overview

Consumers of the 21st century tend to be more aware and demand safe as well as nutritionally balanced food. Unfortunately, conventional thermal processing makes food safe at the cost of hampering nutritional value. The food industry is trying to develop non-thermal processes for food preservation. Pulsed light (PL) is one such emerging non-thermal food processing method that can decontaminate food products or food contact surfaces using white light. Exposure to intense light pulses (in infrared, visible, and ultraviolet (UV) regions) causes the death of microbial cells, rendering the food safe at room temperature. PL technology is an excellent and rapid method of disinfection of product surfaces and is increasingly being used for food surfaces and packaging decontamination, enabling the minimal processing of food. This paper aims to give an overview of the latest trends in pulsed light research, discuss principles of pulse generation, and review applications of various PL systems for the inactivation of microorganisms in vitro, in various food products, and on food contact surfaces. Effects of PL on food quality, challenges of the process, and its prospects are presented.

Intraoperative electrochemotherapy in locally advanced pancreatic cancer: Results and impact on quality of life. a single center experience.

e16731 Background: Locally advanced pancreatic cancer (LAPC) is usually treated with chemoradiotherapy with poor results, thus additional therapies have been proposed. Of the latter, electrochemotherapy (ECT) represents a non-thermal ablation method, which combines the administration of chemotherapeutic drugs with permeabilizing electric pulses for cell membrane electroporation. The present study is the first to assess the short and long-term results, and the quality of life of the patients who underwent ECT for LAPC. Methods: Observational study of patients affected by LAPC who underwent intraoperative ECT after chemoradiotherapy. The inclusion criteria were: 1- patients with LAPC (defined according to the National Comprehensive Cancer Network 2019), 2- previous chemoradiotherapy and 3- absence of disease progression at restaging. Data at diagnosis and at restaging were collected for each patient. The Quality of life was evaluated using the Euro Quality of Life Group Association Questionnaire (EQ-5D-5L). The questionnaire was administered to all patients before and after ECT. Results: From May 25, 2018 to November 26, 2019 five patients underwent ECT: in 4 cases, the tumors were located in the head and, in one, in the body of the pancreas. Preoperative chemotherapy consisted mainly of 6 cycles of modified folfirinox, while the radiotherapy consisted of 54 Gy (27 fractions). At restaging, the serum value of CA 19-9 and tumor size were reduced; however, the vascular involvement did not change. No downstaging was recorded. Intravenous bleomycin 15,000IU/m2 was given as a bolus, the ECT procedure was performed using at least 4 needles with a mean duration time of 27 minutes, (range 15-40). No postoperative mortality or major complications were reported. The mean length of stay was 8 days (range 5-14). Four patients were alive and well at the end of the study while one patient died from disease progression. The mean follow-up was 20.8 months (range 9-34) from diagnosis and 9.4 months (range 2-19) from ECT. The quality of life was good (EQ-5D-5L scale &gt; 50 in all cases) and there was improvement in pain/discomfort with respect to the pre-treatment period in 3 out of 5 patients. Conclusions: Electrochemotherapy can be considered a simple, feasible and safe palliative additional treatment in LAPC without progression after chemoradiotherapy, and it seems to allow a good quality of life and pain improvement.

Difficulties with Use of Cocoa Bean Shell in Food Production and High Voltage Electrical Discharge as a Possible Solution

The cocoa and chocolate industries have huge problems with the utilization of waste generated during the production process. Waste material generated during production include cocoa pod husk, pulp, and cocoa bean shell. Cocoa shell is a by-product that has great potential because of its composition. It consists of dietary fibers, proteins, polyphenols, methylxanthines, etc. However, despite its favorable composition, cocoa shell often cannot be used directly in food production because it may contain components that are harmful for human health. Cocoa shell can carry mycotoxins, different microorganisms, polycyclic aromatic hydrocarbons, and heavy metals. High voltage electrical discharge presents a novel non-thermal method that has great potential for the decontamination of waste materials and can also be used for extraction of valuable compounds from cocoa shell.

Highly Conductive Sb-SnO2 Nanocrystals Synthesized by Dual Nonthermal Plasmas.

Nonthermal plasma synthesis of transparent conducting oxide nanocrystals can offer advantages, for example, ligand-free surfaces, over traditionally used colloidal synthesis methods. When it comes to multicomponent (doped) metal oxide nanocrystal synthesis, uniform distribution of different metal elements and suppressing surface segregation of secondary resistive phases have been concerns. Specifically, surface segregation of resistive secondary phases reduces the electrical conductivity of nanocrystal assemblies. In this work, we demonstrate a nonthermal dual-plasma synthesis method capable of forming Sb-SnO2 (ATO) nanocrystals with a uniform composition distribution and apparently insignificant surface segregation of the dopant. A drastic increase in conductivity was observed in ATO thin films comprised of nanocrystals formed using a dual-plasma configuration compared to nanocrystals formed using a single-plasma configuration. The conductivity values of as-deposited porous films comprised of ATO nanocrystals, prepared using the dual-plasma approach, were on the order of 0.1 S cm-1, which to our knowledge is the highest conductivity reported to-date for that type of high surface area material. Annealing the films comprised of ATO nanocrystals at 500 °C for 2 h in air increased the conductivity and improved ambient stability, without significantly affecting the crystallite size.

Novel Experimental Methods for the Investigation of Hermetia illucens (Diptera: Stratiomyidae) Larvae.

Large-scale insect rearing for food and feed production can be improved by understanding diet digestion and host–microbe interactions. To examine these processes in black soldier fly (Hermetia illucens L.; Diptera: Stratiomyidae) larvae, two protocols were developed. Protocol 1 describes a method to produce viable, sterile black soldier fly larvae and a gentle method for diet sterilization. Sterile black soldier fly larvae can be used to study the diverse role of microbes in larval development. Nutrient requirements of sterile black soldier fly larvae are met only through diet. Viable sterile black soldier fly larvae were consistently generated using a four-step treatment with alternating immersions of eggs for 2 min each in ethanol (70%) and sodium hypochlorite (0.6%), over two cycles. A nonthermal method of diet sterilization, namely high-energy electron beam (HEEB) treatment, was introduced. Subsequently, growth of sterile black soldier fly larvae was observed on the HEEB-treated diets (40, 60, and 40% of replicates with poultry feed, liver pie, and an artificial diet, respectively) but not on autoclaved diets. In Protocol 2, we propose a novel method to collect frass from individual larvae. We then measured the metabolites in frass, using high-pressure liquid chromatography. Results on metabolites confirmed the influence of digestion. For instance, succinate increased from 1 to 2 and 7 μmol/g sample from diet to gut homogenate and frass, respectively. The collection method is a promising tool to estimate the diet and nutrient requirements of black soldier fly larvae, thus increasing the performance and reliability of black soldier fly larvae rearing. We discuss in detail the possible applications and limitations of our methods in black soldier fly larvae research.

Abstract A14: Irreversible electroporation is an “in situ vaccine” and induces antitumor immune responses in pancreatic cancer

Abstract The pancreatic cancer (PC) microenvironment is notoriously immunosuppressive and responds poorly to conventional checkpoint blockade immunotherapy, necessitating a need to overcome this challenge. Irreversible electroporation (IRE) is a nonthermal method of inducing cell death that is currently being used clinically for selected patients with locally advanced PC. Using a robust syngeneic mouse model of PC using cells established from a tumor arising in an LSL-KrasG12D/+; LSL-Trp53R172H/+; PDX1Cre/+; LSL-ROSA26 Luc/+ mouse (KPC), we have demonstrated that IRE alone can serve as an “in situ vaccine” and induce systemic immune responses that prevent secondary tumor growth (prophylactic immunity). We have furthermore demonstrated that these effects are augmented by combination with innate immune activators and PD-1 checkpoint blockade. We observed a significant decrease in immunosuppressive myeloid-derived suppressor cells (MDSCs) (CD11b+, CD11c-, GR1+) at one week in the IRE and drug alone groups with an additive effect in the combination groups. We also saw a profound shift in the ratio of immunostimulatory M1 (MHC II+, CD206 lo): immunosuppressive M2 (MHC II -, CD206 hi) macrophages in the combination groups and a modest increase in CD8+ T cells with IRE alone that was almost doubled in the combination groups with a concomitant decrease in T regulatory cells. Using exome and RNA sequencing of the KPC tumors expressed, nonsynonymous mutations in these tumors were identified and 101 long peptides (20 mer) were generated harboring these mutations at positions 9 and 15. When the CD8+ T-cells post-IRE were incubated along with these mutant peptides and bone marrow-derived dendritic cells, we were able to observe that these T cells were reactive (Interferon gamma secretion) to these neoantigenic peptide pools. Further, we were able to identify specific mutant peptides against which T-cell response was stimulated post IRE that were similar or even better than vaccinating the mice with irradiated KPC cells, suggesting that IRE induced tumor neoantigen-specific prophylactic immune response. Specifically, local delivery of toll-like receptor 7 (TLR7) agonist (1V270) and agonistic CD40 antibody resulted in complete regression of treated primary tumors in 7/10 mice in the experimental group. Increased presence of CD8+ dendritic cells (CD45+ CD11C+) in the draining lymph node suggested that the agonistic CD40 antibody could have triggered increased dendritic cell maturation and cross-presentation. Moreover, it resulted in the complete elimination of the untreated secondary tumors in the group, which IRE as a monotherapy failed to achieve, showing that with appropriate combination strategies, successful therapeutic systemic antitumor immunity can also be achieved with IRE to be used for the management of metastatic PC in the near future. Citation Format: Jayanth S. Shankara Narayanan, Aaron Miller, Tomoko Hayashi, Partha Ray, Stephen Schoenberger, Dennis Carson, Rebekah White. Irreversible electroporation is an “in situ vaccine” and induces antitumor immune responses in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A14.

A novel and simple non-thermal procedure for preparing low-pH-induced surimi gel from Alaska pollock (Theragra chalcogramma) using glucose oxidase

The aim of this study was to develop a novel and simple non-thermal method for preparing a low-pH-induced surimi gel from Alaska pollock (Theragra chalcogramma). To this end, effect of glucose oxidase (GOD) on gelation properties of the surimi with added 5% glucose was investigated. The surimi containing glucose was blended with 0%–3.0% GOD and incubated for 15 h at 4 °C. The pH of the surimi gel with 1.0% GOD decreased to 4.6 after the incubation. The addition of 1.0% GOD was the optimum to elevate breaking force and breaking deformation of the surimi gel. Surface hydrophobicity and disulfide bond contents that are involved in the formation of protein gel network in the surimi increased with an increase in GOD concentration. These results indicate that the addition of 1.0% GOD significantly enhances low-pH-induced gelation of surimi because GOD catalyzes the oxidative reaction of glucose resulting in lowering of the pH.

An Italian experience with mechanochemical ablation of the saphenous vein since 2012

ObjectiveMechanochemical endovenous ablation is a nonthermal method to ablate superficial incompetent veins. The aim of this paper was to assess short-term complications and 5-year follow-up outcomes. MethodsThis is a retrospective single-center study of data collected prospectively. We treated, in an outpatient setting, 395 primary, symptomatic, unilateral, incompetent varicose saphenous veins. No patients were treated bilaterally in the same session. The majority were great saphenous veins (92.3%), and the others were small saphenous veins. Procedures were performed with a mechanochemical endovenous occlusion catheter (ClariVein endovenous occlusion catheter; Merit Medical, South Jordan, Utah) and polidocanol 2% in liquid form. ResultsFollow-up was available for 329 patients treated between September 2012 and September 2017 with a mean follow-up time of 20 ± 18 months (range, 6-60 months). Technical success was achieved in 99.5%; in two patients, we were unable to complete the procedures because of vein spasm leading to catheter damage and inability to infuse the sclerosant. Follow-up was performed with clinical evaluation and duplex ultrasound scan at 1 week, 1 month, 6 months, and 1 year and then once every year. The overall survival rate free from recanalization was 92.4%. Anatomic success is 94% at 1 year, 91% at 2 years, 88% at 3 years, 88% at 4 years, and 84% at 5 years. The follow-up at 5 years includes 23 patients, 5 of whom presented with recanalization; moreover, in this series, in 36% of cases, the veins completely disappeared on duplex ultrasound scan. ConclusionsThe ClariVein catheter is associated with a good occlusion rate, comparable with other techniques including thermal techniques, without major complications.