Combined Carbon Dioxide Research Articles

Abstract: The Effectiveness of Early Combined Fractional CO2 and Pulsed Dye LASER Treatment after Scar Revision

INTRODUCTION: Scars are one of the important complications of the wound healing process that cause physical, psychological and cosmetic effect on the patients. Scar revision and laser treatment have been used over the past century for the improvement of many different types of scars. The purpose of this study is to evaluate the effectiveness of early combined carbon dioxide ablative fractional laser (AFL) and the pulsed dye laser (PDL) after scar revision. MATERIALS AND METHODS: 14 patients underwent scar revision were enrolled for this study. All patients were treated with combined a 10,600 nm AFL and 595 nm PDL. The laser treatments were performed 2 weeks after scar revision surgery, which is the early remodeling phase, at 4 weeks intervals. Four treatments were performed. Vancouver Scar Scale (VSS) scores were evaluated before treatment and 5 months after final laser treatment. RESULTS: Each VSS scores presented statistically significant improvements except height (Fig. 1). There were no adverse complications such as wound disruption, hyperpigmentation and hypopigmentation during the follow up periods. CONCLUSION: This study shows that early combined ablative fractional CO2 and pulse dye laser treatments after scar revision are an effective and safe method to minimize scar formation. DISCLOSURE/FINANCIAL SUPPORT:None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this manuscript.

Numerical simulation and optimization of CO2-enhanced water recovery by employing a genetic algorithm

Carbon dioxide geological sequestration simultaneously combined with water production from deep saline aquifer can effectively address the challenge faced by modern energy systems of reducing carbon dioxide emissions and water intensity while providing reliable, affordable, and secure energy. However, little attention has been paid to date in the literature on determining the carbon dioxide injection strategy for achieving both the optimal water production and the optimal carbon dioxide storage capacity while maintaining operational safety. This paper first establishes three injection–extraction scenarios based on the typical geological parameters of the Junggar Basin in China to analyze the effect of carbon dioxide injection on water extraction and the effect of water extraction on the carbon dioxide storage. The three injection scenarios considered are sole carbon dioxide injection, sole water production and combined carbon dioxide enhanced water recovery. The carbon dioxide enhanced water recovery scenario is then optimized using a genetic algorithm to determine the trade-off between the maximum possible water recovery and the safe carbon dioxide storage for both the constant mass injection and the variable time-dependent mass injection (for achieving constant pressure injection). The influence of number of pumping wells is also analyzed. It can be concluded from this work that the carbon dioxide enhanced water recovery technology can effectively manage the pressure perturbation caused by the carbon dioxide injection as well as the water production while significantly enhancing the carbon dioxide storage capacity, security and water production efficiency. Injection strategy is essential to the efficiency of carbon dioxide enhanced water recovery; the genetic algorithm based optimizer combined with the well-known multi-phase flow solver TOUGH2, designated as GA-TOUGH2 is used for the optimization of injection scenarios. It is found that in the allowable range of pressure perturbations, a higher carbon dioxide injection rate is more beneficial for carbon dioxide storage as well as for water production. Constant pressure injection operation is superior to the constant rate injection and leads to higher carbon dioxide storage capacity and stability, and water production efficiency. Adding pumping wells can somewhat enhance the carbon dioxide storage capacity especially for the constant pressure injection operation compared to the constant rate injection operation as well as the water production efficiency; however, the enhancement in water production is very small compared to the single well and cannot be regarded as economical considering the additional capital cost of well drilling. This paper addresses the method of combined numerical simulation and optimization for carbon dioxide enhanced water recovery from saline aquifers that can be employed in the implementation of enhanced water recovery at industrial scale.

Synergistic effect of supercritical carbon dioxide and peracetic acid on microbial inactivation in shredded Mozzarella-type cheese and its storage stability at ambient temperature

Supercritical carbon dioxide (SCCO2) in combination with peracetic acid (PAA) could represent an effective decontamination technique to control microorganisms in shredded cheese. Preservation of shredded Mozzarella-type cheese (SMC) was assessed at 25 °C over 21 d, using SCCO2 (9.9 MPa, 35 °C, 30 min) individually and combined with PAA at concentrations of 50 (SCCO2/PAA50), and 100 (SCCO2/PAA100) ppm with optional 30-min pre-conditioning time (SCCO2/PAA100PC). Process efficacy was assessed based on achievable inactivation and treatment synergism reflected in counts of inoculated Escherichia coli, Listeria innocua, Geobacillus stearothermophilus spores and indigenous micro-flora such as total bacteria (TBC) and total yeasts and molds (TYMC). Complete inactivation of E. coli cells (≥7.0 log10) in SMC was achieved with any of the combined treatments, whereas initial reduction of L. innocua was lower when SCCO2/PAA50 and SCCO2/PAA100 combinations were applied (2.9 and 4.6 log10, respectively). G. stearothermophilus spores exhibited the highest resistance, allowing for a reduction of up to 3.8 log10 (SCCO2/PAA100) and indicating no advantage of pre-conditioning. However, PAA concentration significantly affected microbial inactivation, comparing SCCO2/PAA100 to SCCO2/PAA50 in TBC (minimum of 6.6 vs. 4.2 log10, respectively) (P < 0.05) and TYMC (minimum of 7.7 vs. 1.1 log10, respectively) (P < 0.05). The TBC and TYMC were not significantly decreased by stand-alone decontamination techniques (P ≥ 0.05); however, synergistic treatment effects (P < 0.05) occurred for all microorganisms except for E. coli. Overall, the findings demonstrate great potential for a SCCO2/PAA hurdle technology as an alternative to post-processing decontamination strategies for production of shelf-stable SMC at ambient temperatures.

Combined steam and carbon dioxide reforming of methane and side reactions: Thermodynamic equilibrium analysis and experimental application

Thermodynamic equilibrium analysis of the combined steam and carbon dioxide reforming of methane (CSCRM) and side reactions was performed using total Gibbs free energy minimization. The effects of (CO2+H2O)/CH4 ratio (0.9–2.9), CO2:H2O ratio (3:1–1:3), and temperature (500–1000°C) on the equilibrium conversions, yields, coke yield, and H2/CO ratio were investigated. A (CO2+H2O)/CH4 ratio greater than 1.2, a CO2:H2O ratio of 1:2.1, and a temperature of at least 850°C are preferable reaction conditions for the synthesis gas preparation in the gas to liquid process. Simulated conditions were applied to the CSCRM reaction and the experimental data were compared with the thermodynamic equilibrium results. The thermodynamic equilibrium results were mostly consistent with the experimental data, but the reverse water gas shift reaction rapidly occurred in the real chemical reaction and under excess oxidizing agent conditions. In addition, a long-term stability test (under simulated conditions) showed that the equilibrium conversion was maintained for 500h and that the coke formation on the used catalyst was not observed.

Assessment of ultra high performance supercritical fluid chromatography as a separation technique for the analysis of seized drugs: Applicability to synthetic cannabinoids

The recent development of modern methods for ultra high performance supercritical fluid chromatography (UHPSFC) has great potential for impacting the analysis of seized drugs. In the separation of synthetic cannabinoids the technique has the potential to produce superior resolution of positional isomers and diastereomers.To demonstrate this potential we have examined the capability of UHPSFC for the analysis of two different groups of synthetic cannabinoids. The first group was a mixture of 22 controlled synthetic cannabinoids, and the second group included JWH018 and nine of its non-controlled positional isomers The clear superiority of UHPSFC over other separation techniques was demonstrated, in that it was capable of near baseline separation of all 10 positional isomers using a chiral column. In total we examined four achiral columns, including Acquity UPC2 Torus 2-PIC, Acquity UPC2 Torus Diol, Acquity UPC2 Torus DEA and Acquity UPC2 Torus 1-AA (1.7μm 3.0×100mm), and three chiral columns, including Acquity UPC2 Trefoil AMY1, Acquity UPC2 Trefoil CEL1 and Acquity UPC2 Trefoil CEL2 (2.5μm 3.0×150mm), using mobile phase compositions that combined carbon dioxide with methanol, acetonitrile, ethanol or isopropanol modifier gradients. Detection was performed using simultaneous PDA UV detection and quadrupole mass spectrometry. The orthogonality of UHPSFC, GC and UHPLC for the analysis of these compounds was demonstrated using principal component analysis. Overall we feel that this new technique should prove useful in the analysis and detection of seized drug samples, and will be a useful addition to the compendium of methods for drug analysis.

In situ Raman quantification of the dissolution kinetics of carbon dioxide in liquid solutions during a dense phase and ultrasound treatment for the inactivation of Saccharomyces cerevisiae

In this work, a Raman based optical approach is presented that enables remote, real time and in situ quantification of the amount of carbon dioxide (CO2) dissolved in distilled water and coconut water during a dense phase carbon dioxide (DPCD) and a combined dense phase carbon dioxide and ultrasound (DPCD+US) pasteurization.CO2 dissolution kinetics were measured in an optically accessible high pressure cell at different temperatures (25, 35, 40°C) and pressures (8 and 12MPa). Two different mixing devices (mechanical and magnetic) during DPCD treatment, and different ultrasound powers (10, 20, 30W) during the DPCD+US treatment were applied. The dissolution data were then related with the inactivation ratio of Saccharomyces cerevisiae inoculated into the solutions. The results demonstrated that an increase of pressure or time during DPCD treatment enhances the amount of CO2 dissolved into the liquid, leading to a higher inactivation degree; the same trend was observed when the temperature was increased, although in this latter case, the amount of dissolved CO2 decreased. The increase of pressure during a combined DPCD+US treatment led to a higher amount of dissolved CO2, which positively influenced the microbial inactivation while no effect was obtained increasing the ultrasound power. Concerning the effect of the mixing devices, the mechanical stirrer was the one that enhanced the pasteurization efficiency as it influenced CO2 dissolution kinetics and, consequently, the microbial inactivation ratio. The composition of the liquid solutions also influenced the amount of dissolved CO2 but no correlations were found with S. cerevisiae inactivation.

Combined replacement and depressurization methane hydrate recovery method

A new method for exploiting natural gas from methane hydrates, which combines carbon dioxide replacement and depressurization, was investigated in a 288-ml high-pressure vessel of 288 ml. Experimental results with and without depressurization were compared to reveal the effects of depressurization on the final replacement percentage. Results showed that the CH4–CO2 replacement reaction could be divided into two stages. The first stage lasts for about 4 h and can be described as the surface reaction stage; the reaction in this stage is rapid, and the results fit the Avrami model. In the second stage, the rate of the reaction is slow due to hydrates blocking the diffusion pathways. As the replacement reaction is restricted by the diffusion and transportation of CO2, partial melting of methane hydrates through depressurization enhances the second stage. This is because the melting of methane hydrates provides pathways for CO2 to penetrate into the inner layer of the hydrates. The combined method improves the replacement percentage. However, the effects of depressurization on the stability of the sediments remain to be explored.

Minimizing revision rates with the “Π” technique for bilateral vocal fold immobility: A new technique combining carbon dioxide and diode laser

For more than 25 years, posterior laser transverse cordotomy has been generally considered the ideal endoscopic minimally invasive procedure of choice for bilateral vocal fold immobility. The main drawback of this procedure, when compared to more aggressive "glottic aperture improvement" operations, is the high revision rates, caused by granulations, adhesion, and scar, for example. We describe a technique using a combination of conventional and flexible lasers. Our technique seems to minimize the revision rates. This new technique combining CO2 and diode laser is a safe alternative for treating bilateral vocal fold palsies.

A combined high pressure carbon dioxide and high power ultrasound treatment for the microbial stabilization of cooked ham

The feasibility of a combined treatment based on high pressure carbon dioxide and high power ultrasound (HPCD + HPU) technologies was investigated for the microbial stabilization of cooked ham and compared with the one of HPCD alone. Inactivation kinetics of the natural microbiota (mesophilic microorganisms, lactic acid bacteria, yeasts and molds) were determined at 12 MPa, 40 and 45 °C, 10 and 20 W (delivered continuously or every 2 min during the combined treatment) from 2 up to 15 min. Additionally, a shelf life study of the product treated at the optimal process conditions was performed for 4 weeks at 4 °C to evaluate the effects of the combined process on its quality (pH, acidity, color and texture) and long term stability.At 12 MPa, 45 °C and 10 W delivered every 2 min of treatment, inactivation to undetectable levels of lactic acid bacteria, yeasts and molds was achieved after 15 and 4 min while 4 log reductions of mesophilic microorganisms was obtained after 15 min of the combined treatment. On the contrary, HPCD performed alone induced the same inactivation degree of mesophilic and lactic acid bacteria increasing the treatment time to 60 and 45 min, respectively. The microbial stability of the product was assured up to 3 weeks of storage. The analysis of the quality attributes revealed that the pH, acidity and texture remained stable for the entire storage time while color changes were perceivable after the second week. Overall, the results showed the feasibility and potential of HPCD + HPU as an innovative non-thermal tool for the microbial stabilization of ready-to-eat meat.

Numerical modeling of combined low salinity water and carbon dioxide in carbonate cores

This paper investigates the combined effect of injecting low salinity water (LSWI) and carbon dioxide (CO2) on oil recovery from carbonate cores. The combined effect of LSWI and CO2 injection on oil recovery was predicted by performing several 1D simulations using measured reservoir rock and fluid data. These simulations included the effect of salinity on both miscible and immiscible continuous gas injection (CGI), simultaneous water-alternating-gas (SWAG), constant water-alternating-gas (WAG), and tapered (WAG). For SWAG and constant and tapered WAG, both seawater and its dilutions were simulated. CO2 was injected above its minimum miscibility pressure. Baker's three-phase relative permeability model was modified to account for the effect of salinity on the water/oil relative permeability. The results show that SWAG, whether using seawater or its dilutions, outperformed all other tertiary injection modes in terms of oil recovery. Moreover, the SWAG process has both the highest tertiary recovery factor (TRF) and the lowest utilization factor (UF). This study highlights the advantage of using low salinity water along with miscible CO2. The miscible CO2 displaces the residual oil saturation whereas the low salinity water boosts the production rate by increasing the oil relative permeability through wettability alteration towards more a water-wet state. The latter finding was supported by comparing our simulations with the two corefloods reported by Chandrasekhar and Mohanty (2014). These corefloods were conducted in SWAG tertiary mode using seawater and its dilutions. Fractional flow analysis shows that SWAG with low salinity water requires less injected solvent compared to SWAG with seawater and miscible CGI.

Supercritical carbon dioxide-mediated hydrothermal extraction of bioactive compounds from Garcinia Mangostana pericarp

Supercritical carbon dioxide in combination with hydrothermal process was used in the extraction of bioactive compounds from Garcinia mangostana pericarp. The extraction was carried out following pre-defined ranges of temperature (120–160°C), pressure (5–15MPa), extraction time (30–120min), and particle size (0.3–0.9mm), that served as parameters for determination of optimum yield. The extracts were subsequently analyzed for their total polyphenolic contents, antioxidant activity, and alpha-mangostin recovery.The multi-variable extraction process yielded several possible responses. Using response surface methodology (RSM) with central composite design (CCD), the optimal response obtained a yield of 39.9% w/w, with 22.0gGAE/100gextract of total polyphenolic contents, together with 73.2μg/mL of antioxidant activity and 0.203% w/wextract recovery of alpha-mangostin.

Palladium‐Catalyzed Carboxylation of Benzyl Chlorides with Atmospheric Carbon Dioxide in Combination with Manganese/Magnesium Chloride

AbstractAn efficient direct carboxylation of a series of benzyl chlorides with CO2 catalyzed by Pd(OAc)2/dicyclohexyl (2′,6′‐dimethoxy‐[1,1′‐biphenyl]‐2‐yl)phosphine (SPhos) was developed to afford the corresponding phenylacetic acids in combination with Mn powder as a reducing reagent and MgCl2 as an indispensable additive. The reaction proceeded smoothly under 1 atm CO2. The application of Mn powder instead of a sensitive reducing reagent represents an operationally simple access to phenylacetic acids. Notably, MgCl2 is able to stabilize the (SPhos)2PdII(Bn)(Cl)(η1‐CO2)(MgCl2) adduct and thus facilitates CO2 insertion into the PdII−C bond, which is supported by a DFT study.

Management and prevention of foreign body aspiration in children

Objective To put forward the prevention advice on foreign body suction, and to discuss the efficacy, safety and application experience of flexible bronchoscopy in the diagnosis and treatment of tracheobronchial foreign bodies in children. Methods The treatment experience of 38 cases for airway foreign body removal with flexible bronchoscopy and granulation tissue proliferation in Argon plasma coagulation(APC)(argon knife) combining carbon dioxide(CO2) cryotherapy in Bayi Children's Hospital Affiliated to General Hospital of Beijing Military Command from January 2013 to December 2014 were reviewed, and the clinical data including age, gender, treatment time for inhaled foreign body, clinical and X-ray manifestations, location of the foreign body, treatment with bronchoscopy with APC and cryotherapy, complications and outcomes were analyzed. Results There were 38 cases of patients including 31 male(81.6%) and 7 female(18.4%), aged from 10 months to 14 years old, with mean age 28.5 months; among them there were 30 cases with definite history of foreign body, accounting for 78.9%; the most common clinical symptom was cough among the cases, accounting for 84.3%; X ray showed 15 cases with ipsilateral lung atelectasis, accounting for 39.5%, emphysema in 17 cases, accounting for 44.7%, pneumonia change in 6 cases, accounting for 15.8%, there were 11 cases who had lung computerized tomography examination when coming to the hospital, and only 1 case could be seen to have foreign body shadow; microscopic examination found that inhaled foreign body in the right bronchus accounted for 57.9%, and peanut was the main foreign body inhalation in this group; only 4 cases(10.5%) had definite diagnosis and foreign body removal within 24 h after foreign body aspiration, moreover, 34 cases(89.5%) with foreign body aspiration got the diagnosis and treatment after 24 h; crying was the primary inducement for inhaled foreign body.All the 38 cases of children with inhaled foreign body experienced removal under flexible bronchoscopy.There were 19 cases(50.0%) who had granulation tissue proliferation around the foreign body, among which 5 cases of foreign body was wrapped by the proliferation of granulation tissue, with APC dealing with the granulation tissue of foreign body surface to remove foreign body after exposure, then giving CO2 cryotherapy.Nevertheless, there were 9 cases of foreign body who had granulation tissue but was not wrapped, receiving CO2 cryotherapy directly after the foreign body removal.One case of this group had bradycardia during the surgery, and 2 cases had postoperative bleeding, but there was no death cases with foreign bodies removal. Conclusions Education is the key to prevent foreign body aspiration in infants under 3 years old.Flexible bronchoscopy is safe to remove foreign bodies from the respiratory tract and has fewer complications, so it is one of the alternative methods in diagnosis and treatment of foreign body inhalation. Key words: Flexible bronchoscopy; Tracheobronchial foreign body; Argon plasma coagulation; Freezing techniques; Granulation tissue; Child

Feasibility of simultaneous CO2 storage and CH4 production from natural gas hydrate using mixtures of CO2 and N2

Production of natural gas from hydrate using carbon dioxide allows for a win-win situation in which carbon dioxide can be safely stored in hydrate form while releasing natural gas from in situ hydrate. This concept has been verified experimentally and theoretically in different laboratories worldwide, and lately also in a pilot plant in Alaska. The use of carbon dioxide mixed with nitrogen has the advantage of higher gas permeability. Blocking of flow channels due to formation of new hydrate from injected gas will also be less compared to injection of pure carbon dioxide. The fastest mechanism for conversion involves the formation of a new hydrate from free pore water and the injected gas. As a consequence of the first and second laws of thermodynamics, the most stable hydrate will form first in a dynamic situation, in which carbon dioxide will dominate the first hydrates formed from water and carbon dioxide / nitrogen mixtures. This selective formation process is further enhanced by favorable selective adsorption of carbon dioxide onto mineral surfaces as well as onto liquid water surfaces, which facilitates efficient heterogeneous hydrate nucleation. In this work we examine limitations of hydrate stability as function of gradually decreasing content of carbon dioxide. It is argued that if the flux of gas through the reservoir is high enough to prevent the gas from being depleted for carbon dioxide prior to subsequent supply of new gas, then the combined carbon dioxide storage and natural gas production is still feasible. Otherwise the residual gas dominated by nitrogen will still dissociate the methane hydrate, if the released in situ CH4 from hydrate does not mix in with the gas but escapes through separate flow channels by buoyancy. The ratio of nitrogen to carbon dioxide in such mixtures is therefore a sensitive balance between flow rates and formation rates of new carbon dioxide dominated hydrate. Hydrate instability due to undersaturations of hydrate formers have not been discussed in this work but might add additional instability aspects.

Spontaneously Breathing Preterm Infants Change in Tidal Volume to Improve Lung Aeration Immediately after Birth

To examine the temporal course of lung aeration at birth in preterm infants <33 weeks gestation. The research team attended deliveries of preterm infants <33 weeks gestation at the Royal Alexandra Hospital. Infants who received only continuous positive airway pressure were eligible for inclusion. A combined carbon dioxide (CO2) and flow-sensor was placed between the mask and the ventilation device. To analyze lung aeration patterns during spontaneous breathing, tidal volume (VT), and exhaled CO2 (ECO2) were recorded for the first 100 breaths. Thirty preterm infants were included with a total of 1512 breaths with mask leak <30%. Mean (SD) gestational age and birth weight was 30 (1) weeks and 1478 (430) g. Initial VT and ECO2 for the first 30 breaths was 5-6 mL/kg and 15-22 mm Hg, respectively. VT and ECO2 increased over the next 20 breaths to 7-8 mL/kg and 25-32 mm Hg, respectively. For the remaining observation period VT decreased to 4-6 mL/kg and ECO2 continued to increase to 35-37 mm Hg. Preterm infants begin taking deeper breaths approximately 30 breaths after initiating spontaneous breathing to inflate their lungs. Concurrent CO2 removal rises as alveoli are recruited. Lung aeration occurs in 2 phases: initially, large volume breaths with poor alveolar aeration followed by smaller breaths with elimination of CO2 as a consequence of adequate aeration.

The Influence of Promoter on Ni(15)/La(5)/γ-Al2O3 Catalyst in CO2-Steam Reforming of Methane to Syngas at High Pressure.

Catalysts were investigated with respect to catalytic activity and coke formation in combined steam and carbon dioxide reforming of methane to develop a highly active and stable catalyst for gas to liquid processes. Ni/La-X/Al2O3 (X = Co, Ce, Mo) catalysts were prepared by an impregnation method. The combined steam and carbon dioxide reforming of methane reaction were studied as a function of high pressure (20 bar) in a fixed bed reactor system. X-ray diffraction, BET surface area, and H2-temperature programmed reduction were used to observe the characteristics of the prepared catalysts. Coke formation of used catalysts was examined by scanning electron microscopy, transmission electron microscopy and the coke amount of used catalysts was measured by thermo gravimetric analysis. Catalysts with smaller particle size had a higher temperature of reduction, which had a positive effect on catalytic activity. The improvement in active site rise and dispersion and the lowest metal crystal size had an effect on catalyst activity. As a result, the Ni/La-Co/Al2O3 catalyst showed the highest activity at a reaction temperature of 800 degrees C and a reaction pressure of 20 bar.

High pressure carbon dioxide combined with high power ultrasound pasteurization of fresh cut carrot

Nowadays, combination of innovative technologies aiming to obtain additive or synergistic effects on microbial inactivation of food products compared to the single processes is considered a field of great interest. In this context, the feasibility of a combined high pressure carbon dioxide and high power ultrasound (HPCD+HPU) treatment was tested for the pasteurization of fresh cut carrot.Inactivation kinetics of the natural microbial flora (mesophilic microorganisms, lactic acid bacteria, total coliforms and yeasts and molds) were determined at 12MPa and 10W delivered every 2min of treatment as a function of temperature (22, 35 and 40°C) and time (from 5 up to 30min). Further Escherichia coli was spiked on fresh cut carrot and inactivation kinetics were obtained at 6, 8, 10MPa and 10W delivered every 2min of treatment as a function of temperature (22 and 35°C) and times (from 3 up to 30min). The results of the inactivation kinetics were compared with those obtained with thermal, HPU and HPCD treatments.Additionally color, pH, acidity, texture and sensory analyses of the samples were performed to assess the quality of HPCD+HPU treated carrots in comparison with the fresh product.It was demonstrated that the combined treatment was not able to induce a greater reduction of the natural microbial flora at milder process conditions compared to HPCD. At 40°C, 12MPa, 15min and 10W still a residual load of mesophilic microorganisms was detected. On the contrary, the inactivation kinetics of E. coli showed a faster reduction: 3min at 10MPa, 35°C and 10W were enough to obtain 8log reductions.Texture and sensory analyses revealed significant changes of HPCD+HPU treated samples with great reduction of firmness, friability and crispiness. The results showed the potentials and limits of the combined technology applied to fresh cut vegetables.

Combined Carbon Dioxide Laser with Photodynamic Therapy for Nodular and Superficial Basal Cell Carcinoma

Basal cell carcinomas (BCCs) are often seen by general practitioners, plastic surgeons, and dermatologists in the outpatient setting. Photodynamic therapy (PDT) and CO2 laser when used as monotherapy have been successfully used to treat small BCC, with greatest success in the superficial histological subtype but have limitations compared to surgical excision due to a limited depth of penetration of PDT (2 mm absorption) limiting efficacy. We describe our experience of dual-modality treatment improving efficacy, cosmetic outcomes, and minimizing recurrence. One hundred ten patients with a total of 177 lesions mainly on the head and neck were treated with combined therapy using an UltraPulse CO2 laser and PDT using methyl aminolevulinate (METVIX) at the same sitting, with repeat PDT 1 week later. We evaluated recurrences, cosmetic outcomes, patient satisfaction, and costs. The mean age of patients was 67 years. The mean follow-up period was 32.2 months, with a range of 7.7 to 68.5 months. Eighty six lesions were followed up for more than 3 years. A total of 177 lesions were diagnosed and treated. Only biopsy-proven BCCs were included in this study. Histologically, 34 (19.2%) were superficial subtype, 50 (28.2%) nodular, 9 (5.08%) infiltrative, 7 (3.95%) morpheic, 3 (1.69%) mixed, and in 74 (41.8%) diagnosis was simply BCC. All lesions responded to treatment as assessed by clinical evaluation with regular follow-up. The total recurrence-free rate was 97.1%. In 88.1% lesions, a single cycle of treatment was required; 9.03% had 2 cycles and 0.56% underwent 3 cycles. In 3 of the patients, no data were available. Recurrences were noted in 5 (2.82%) cases. All recurrences were treated successfully, all but one using repeat laser-PDT. One patient underwent surgical excision. No significant complications were encountered, although mild hypopigmentation was occasionally seen and some discomfort is experienced with PDT. Combined CO2 laser and PDT have equivalent cure rates to surgery for BCCs--notably of the nodular subtype--these modalities acting synergistically. This strategy provides cure often with scarless outcomes as illustrated. Laser with PDT is most appropriate for patients who value excellent cosmetic outcomes and where avoidance of an invasive procedure is an important factor. In addition, this modality comes into its own for specific groups of patients, such as those on Warfarin or those with diffuse or multiple lesions.

Partial permeabilisation and depolarization of Salmonella enterica Typhimurium cells after treatment with pulsed electric fields and high pressure carbon dioxide

The aim of the present study is to investigate the efficiency of the combined pulsed electric fields and high pressure carbon dioxide (PEF+HPCD) treatment on the Gram-negative pathogen Salmonella Typhimurium in a liquid medium, by means of both plate count technique and flow cytometry (FCM). PEF was applied at two conditions: (1) 1 single pulse of 1ms length at 30kV/cm and (2) 12 pulses of 4ms length at 30kV/cm, while HPCD at 12MPa, 22°C and 35°C for different treating times (0–45min). At both temperatures, the application of PEF as HPCD pre-treatment was demonstrated to enhance the inactivation kinetics and to decrease the treatment time to inactivate S. Typhimurium if compared to HPCD alone. Further, the approach based on FCM permitted to investigate the functional status of bacterial cells after PEF and HPCD treatments distinguishing among viable bacteria (considered as intact cells), permeabilised cells and depolarised cells simultaneously. It has been demonstrated that the synergistic effect is due to the electroporation effect of PEF which lead to changes in the cell membrane potential but also in a partial structural damage, favoring the subsequent CO2 penetration into the cells and increasing the inactivation kinetics, thus improving the efficiency of the entire process.

High pressure carbon dioxide combined with high power ultrasound processing of dry cured ham spiked with Listeria monocytogenes

Traditionally, thermal treatments for the inactivation of Listeria monocytogenes in meat products involve undesirable changes of the product quality. In recent years, efforts have been carried out to develop alternative methods to inactivate L. monocytogenes without affecting the product quality attributes. In this context, the feasibility of combined high pressure carbon dioxide and high power ultrasound (HPCO2+HPU) treatment to inactivate L. monocytogenes inoculated on the surface of dry cured ham was investigated. Inactivation data were determined at 6, 8 and 12MPa, as a function of temperature (22, 35, 45°C) and treatment time (0.5 to 30min), and compared to those obtained after thermal and HPCO2 treatments.Color, pH and acidity changes of the samples after both thermal and HPCO2+HPU treatments were measured and compared, sensorial profile of the treated samples was evaluated by a sensory panel and shelf-life was determined by a storage study for 4weeks at 4°C.The results clearly revealed that HPU alone was not able to induce any microbial inactivation while HPCO2+HPU treatment always assured a certain level of inactivation, variable with the process temperature used: the inactivation efficiency was demonstrated higher at 35°C rather than 22°C and no enhancement was observed at 45°C compared to 35°C. Process conditions of 12MPa, 35°C, at 10W for 5min assured inactivation to undetectable level of L. monocytogenes spiked on the surface of the product with an initial concentration of about 109CFU/g. No differences were detected between acidity, pH, color and sensory attributes of the untreated and HPCO2+HPU treated dry cured ham surface, while slight differences were measured between the values obtained for the untreated and thermally treated samples. Additionally, the storage study demonstrated that a full microbial and quality shelf-life was assured for 4weeks at 4°C. The results obtained may open the doors to the application of such an innovative process at industrial level, in particular to treat ham-type or meat products.