Low-frequency Ultrasound Treatment Research Articles

Effects and improvement mechanisms of ultrasonic pretreatment on the quality of fermented skim milk

Fermented skim milk is an ideal food for consumers such as diabetic and obese patients, but its low-fat content affects its texture and viscosity. In this study, we developed an effective pretreatment method for fermented skim milk using low-frequency ultrasound (US), and investigated the molecular mechanism of the corresponding quality improvement. The skim milk samples were treated by optimal ultrasonication conditions (336 W power for 7 min at 3 °C), which improved the viscosity, water-holding capacity, sensory attributes, texture, and microstructure of fermented skim milk (P < 0.05). Further mechanistic analyses revealed that the US treatment enhanced the exposure of fluorescent amino acids within proteins, facilitating the cross-linking between casein and whey. The increased surface hydrophobicity of fermented milk indicates that the US treatment led to the exposure of hydrophobic amino acid residues inside proteins, contributing to the formation of a denser gel network; the average particle size of milk protein was reduced from 24.85 to 18.06 µm, which also contributed to the development of a softer curd texture. This work is the first attempt to explain the effect of a low-frequency ultrasound treatment on the quality of fermented skim milk and discuss the molecular mechanism of its improvement.

Effects of low-frequency ultrasound combined with anti-MRSA agents on the mouse model of pulmonary infection.

The treatment of methicillin-resistant Staphylococcus aureus (MRSA)-induced pneumonia with antibiotics alone poses considerable challenges. To address these challenges, low-frequency ultrasound (LFU) emerges as a promising approach. In this study, a mouse pneumonia model was established through intratracheal injection of MRSA to investigate the therapeutic efficacy of LFU in combination with antibiotics. Minimal inhibitory concentration was assessed, and the distribution of antibiotics in the lung and plasma was determined using liquid chromatography coupled with mass spectrometry. Various parameters, including the survival rate, histopathology, lung bacterial clearance, and the expressions of cytokines and inflammation-related genes, were evaluated before and after treatment. Compared with the infection group, both the antibiotic-alone groups [vancomycin (VCM), linezolid, and contezolid (CZD)] and the groups in combination with LFU demonstrated an improvement in the survival status of mice. The average colony-forming units of lung tissue in the LFU combination groups were lower compared with the antibiotic-alone groups. While no significant changes in C-reactive protein and procalcitonin in plasma and bronchoalveolar lavage fluid were observed, histopathological results revealed reduced inflammatory damage in LFU combination groups. The secretion of interleukin-6 and tumor necrosis factor-alpha was decreased by the combination treatment, particularly in the VCM + LFU group. Furthermore, the expressions of MRSA virulence factors (hla and agrA) and inflammation-related genes (Saa3, Cxcl9, and Orm1) were further reduced by the combinations of LFU and antibiotics. Additionally, LFU treatment facilitated the distribution of VCM and CZD in mouse lung tissue at 30 and 45 min, respectively, after dosage.IMPORTANCETreating pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) with antibiotics alone poses significant challenges. In this in vivo study, we present compelling evidence supporting the efficacy of low-frequency ultrasound (LFU) as a promising approach to overcome these obstacles. Our findings demonstrated that LFU enhanced the effectiveness of vancomycin, linezolid, and contezolid in an MRSA pneumonia model. The combination of LFU with anti-MRSA agents markedly improved the survival rate of mice, accelerated the clearance of pulmonary bacteria, reduced inflammatory injury, inhibited the production of MRSA endotoxin, and enhanced the distribution of antibiotics in lung tissue. The application of LFU in the treatment of pulmonary infections held substantial significance. We believe that readers of your journal will find this topic of considerable interest.

Low-Frequency Ultrasound Effects on Cellulose Nanocrystals for Potential Application in Stabilizing Pickering Emulsions.

Cellulose, in the form of cellulose nanocrystals (CNCs), is a promising biomaterial for stabilizing Pickering emulsions (PEs). PEs are commonly formed using low-frequency ultrasound (LFU) treatment and impact CNC properties. The present study investigated the specific effects of LFU treatment on CNCs' chemical and physical properties. CNCs were characterized using dynamic light scattering, ζ;-potential determination, Fourier transform infrared spectroscopy, X-ray diffraction, and contact angle measurement. CNC suspensions were studied using rheological analysis and static multiple light scattering. LFU treatment broke CNC aggregates and modified the rheological behavior of CNC suspensions but did not affect the CNCs' chemical or crystallographic structures, surface charge, or hydrophilic properties. During the storage of CNC suspensions and PEs, liquid crystal formation was observed with cross-polarized light. Hypotheses related to the impact of liquid crystal CNCs on PE stability were proposed.

Liquid crystalline nanogel targets skin cancer via low-frequency ultrasound treatment

The potential of low-frequency ultrasound (LFU) combined with nanotechnology-based formulations in improving skin tumors topical treatment was investigated. The impact of solid lipid nanoparticles (SLN) and hydrophilic nanogels as coupling media on LFU-induced skin localized transport regions (LTR) and the penetration of doxorubicin (DOX) in LFU-pretreated skin was evaluated. SLN were prepared by the microemulsion technique and liquid crystalline nanogels using Poloxamer. In vitro, the skin was pretreated with LFU until skin resistivity of ∼1 KΩ.cm2 using the various coupling media followed by evaluation of DOX penetration from DOX-nanogel and SLN-DOX in skin layers. Squamous cell carcinoma (SCC) induced in mice was LFU-treated using the nanogel with the LFU tip placed 5 mm or 10 mm from the tumor surface, followed by DOX-nanogel application. LFU with nanogel coupling achieved larger LTR areas than LFU with SLN coupling. In LFU-pretreated skin, DOX-nanogel significantly improved drug penetration to the viable epidermis, while SLN-DOX hindered drug transport through LTR. In vivo, LFU-nanogel pretreatment with the 10 mm tip distance induced significant tumor inhibition and reduced tumor cell numbers and necrosis. These findings suggest the importance of optimizing nanoparticle-based formulations and LFU parameters for the clinical application of LFU technology in skin tumor treatment.

High-intensity, Low-frequency Ultrasound Treatment as Sustainable Strategy to Develop Innovative Biomaterials from Agri-food Byproducts and Wastes

Bioconversion is an important avenue for finding value from biomass waste produced by the agricultural industry. One avenue of conversion is the development of upcycling byproducts and waste from food processing to value-added products. This includes degradable biomaterials which have real potential to reduce waste, improving economic, social and environmental impacts. As such, this research paper was focused on exploring two avenues of bioconversion from waste products of tomato skin, hemp meal and hops vines: identification of phytochemicals and the development of bioplastic. Combined to these researches, the effect of Ultrasound as a green technology was studied in both contexts. It was found that Ultrasound treatment reduced extraction time for saponin and phenolic acid from tomato skin, hemp meal and/or hops vines from 24h to 30 min. However, Ultrasound Assisted Extraction (UAE) was shown to affect the phenolic acid and saponin profiles of certain extracts. &#x0D; &#x0D; Ultrasound treatment was shown to positively impact the overall microscopic structure and qualities of bioplastic such as water activity, percentage moisture, hardness, cohesiveness, resilience, and springiness index. This study suggests that Ultrasound can be used as sustainable non-thermal method for extraction of active saponins and phenolics but also in bioplastic formulation to enhance physico-chemical characteristic.

Enhancement of γ-aminobutyric acid and relevant metabolites in brown glutinous rice (Oryza sativa L.) through salt stress and low-frequency ultrasound treatments at pre-germination stage

In order to fortify γ-aminobutyric acid (GABA) of brown glutinous rice (BGR), pre-germination strategy was employed, and effects of low-frequency (28 kHz) ultrasound treatment combined with CaCl2 stress on the sprout length, germination rate, morphology, color, water, total polyphenol content (TPC), starch, protein, GABA contents and relevant metabolites were investigated. The germination rate would be inhibited under CaCl2 concentration ≥ 2.0 % during 24 h soaking without ultrasound treatment, and no significant difference was also observed combined with 9 h ultrasound treatment. Ultrasound treatment was beneficial to water absorption, TPC enrichment, energy metabolism, lipid metabolism and protein hydrolysis. Higher contents of GABA (3.29 folds), pyruvic acid (7.63 folds), glycerol (4.88 folds), glutamate (2.02 folds) and glucose (1.32 folds) were obtained due to the antagonistic effect between the 30 w ultrasound treatment and 2.0 % CaCl2 stress at the 9 h pre-germination, and energy, lipid and protein metabolomic pathways were all involved in the GABA accumulation.

Low-frequency ultrasound irradiation increases paclitaxel-induced sarcoma cells apoptosis and facilitates the transmembrane delivery of drugs.

Sarcoma is a malignant tumor derived from interstitial tissues and requires comprehensive treatment including chemotherapy. Paclitaxel (PTX) is an active agent against sarcoma, but its effect is not sufficiently acceptable and needs to be improved. Low-frequency ultrasound (LFU) has been documented to improve the efficacy of drugs by inducing reversible changes in membrane permeability; however, the effects of the combined use of LFU and PTX for sarcoma tumors remain unclear and warrant further investigation. We investigated the effects of 30kHz LFU treatment combined with PTX on sarcoma cells A-204 and HT-1080 by analyzing in vitro apoptosis and cell growth inhibition rates, and determined their antitumor effects by examining tumor weights with or without LFU in the S180 sarcoma xenograft model. Drug concentrations in the subcutaneous tumors were measured using high performance liquid chromatography (HPLC). LFU combined with PTX significantly induced cell apoptosis, and blocked the cell cycle of sarcoma cells in G2/M phase, and furthermore, inhibited the activation of JAK2/STAT3 signaling pathway. Meanwhile, LFU combined with PTX inhibited the expression of PD-L1 in vitro, suggesting the potential of enhanced antitumor immunity by this treatment. LFU combined with PTX significantly inhibited the growth of S180 tumors transplanted subcutaneously in Institute of Cancer Research (ICR) mice, and its enhanced effect may be associated with increased local concentrations of PTX in tumor tissues in vivo, with no significant adverse subsequences on body weight observed. We conclude that the combination of LFU and PTX has synergistic antitumor effects and is a candidate for subcutaneous treatment of sarcoma by further increasing the intracellular concentration of PTX.

Synergistic effect of low-frequency ultrasound and antibiotics on the treatment of Klebsiella pneumoniae pneumonia in mice.

The antibiotic-resistant Klebsiella pneumoniae (Kp) has become a significant crisis in treating pneumonia. Low-frequency ultrasound (LFU) is promising to overcome the obstacles. Mice were infected with bioluminescent Kp Xen39 by intratracheal injection to study the therapeutic effect of LFU in combination with antibiotics. The counts per second (CPS) were assessed with an animal biophoton imaging system. Bacterial clearance, histopathology, and the concentrations of cytokines were determined to evaluate the therapeutic effect. LC-MS/MS was used to detect the distribution of antibiotics in the lung and plasma. LFU in combination with meropenem (MEM) or amikacin (AMK) significantly improved the behavioural state of mice. The CPS of the LFU combination group were more significantly decreased compared with those of the antibiotic alone groups. The average colony-forming units of lung tissue in the LFU combination groups were also lower than those of the antibiotic groups. Although no significant changes of cytokines (IL-6 and TNF-α) in plasma and bronchoalveolar lavage fluid were observed, LFU in combination with antibiotics showed less inflammatory damage from histopathological results compared with the antibiotic-alone groups. Moreover, 10min of LFU treatment promoted the distribution of MEM and AMK in mouse lung tissue at 60 and 30 min, respectively, after dosage. LFU could enhance the effectiveness of MEM and AMK in the treatment of Kp-induced pneumonia, which might be attributed to the fact that LFU could promote the distribution of antibiotics in lung tissue and reduce inflammatory injury.

Enhanced thrombolysis by endovascular low-frequency ultrasound with bifunctional microbubbles in venous thrombosis: in vitro and in vivo study.

There is a need to improve the efficacy and safety of endovascular techniques in venous thrombotic diseases, and microbubble enhanced sonothrombolysis is a promising approach. However, whether endovascular low-frequency ultrasound (LFUS) can be utilized in microbubble enhanced sonothrombolysis is unclear. Here, we present a catheter-based thrombolytic system that combines unfocused low-frequency low-intensity ultrasound with novel fibrin-targeted drug-loaded bifunctional microbubbles. We develop an in vitro flow model and an in vivo rabbit inferior vena cava (IVC) thrombosis model to evaluate the safety and efficacy of the thrombolytic system. The results indicate that microbubble enhanced sonothrombolysis with endovascular LFUS treatment for 30 min is equally effective compared to pure pharmacologic treatment. Furthermore, the thrombolytic efficacy of this system is safely and substantially improved by the introduction of a fibrin-targeted drug-loaded bifunctional microbubble with a reduction of the fibrinolytic agent dosage by 60%. The microbubble enhanced endovascular LFUS sonothrombolysis system with excellent thrombolytic efficacy may serve as a new therapeutic approach for venous thrombotic diseases.

Miniature sono-electrochemical platform enabling effective and gentle electrode biofouling removal for continuous sweat measurements

• Sono-electrochemical lab-on-a-chip device with gigahertz bulk acoustic resonator. • Acoustic actuation in-situ releasing fouled electrode′s electrochemical activity. • Non-invasiveness to intrinsic film electrode and the decorated nanoparticles. • Continuous and repeatedly electrochemical measurements to human sweat. Developing miniature smart electrochemical sweat sensors to perform continuous and noninvasive health diagnosis at molecule level is in the spotlight. Sensor's biofoulings hinder the targets' approaching, decreasing the detection sensitivity over time and further limiting the accurate analysis. Effective cleaning to remove biofoulings on electrochemical sensors is a main challenge and needs to overcome urgently for such purpose. We propose a miniature sono-electrochemical platform utilizing submillimeter gigahertz acoustic resonator to effectively clean away the biofoulings and release sensors inherent electrochemical activities. Resonator induced super strong fluid streaming can completely and repeatedly remove sweat biofoulings from gold electrode surface, leading to 100% recovery of sensor’s activities for continuous reliable measurements. Compared with common sensor renewal strategies, such as acidic or basic solution cleaning, mechanical polishing, traditional low frequency ultrasound treatment, this electrode surface renewal technique is stable, mathematically predictable, effective and gentle so that it does not cause any destructions to inherent electrode surface, and therefore the sensed electrochemical signals on raw and cleaned electrodes are comparable and improvable with no unexpectable deviation. Together with submillimeter size of the resonator, it shows potential to be integrated within wearable electroanalytical microfluidics for developing smart device to carry out continuous health diagnosis.

Low frequency ultrasound treatment enhances antibrowning effect of ascorbic acid in fresh-cut potato slices

Ascorbic acid (AsA) is generally used as an antibrowning agent for fresh-cut potato (FCP). However, its browning inhibitory effect is temporary because of its rapid consumption during redox processes. In this study, the effect of browning inhibition in FCP slices was evaluated using low frequency ultrasound (LFU; 40 kHz, 200 W, 3 min) and AsA (0.2%, w/v) treatments alone or in combination. The results showed that LFU combined with AsA (LFU-AsA) treatment could achieve a better antibrowning effect than either treatment alone (higher L*, lower a* and ΔE*), and there was no adverse effect on texture properties. LFU-AsA treatment not only inhibited the activity of PPO more effectively than AsA treatment, but also enhanced the antibrowning effect by retaining higher AsA content. Moreover, it also maintained membrane integrity by limiting lipid peroxidation and solute migration during storage. Overall, LFU-AsA treatment would be a promising method in food preservation industries.

Influence of combined salt concentration and low-frequency ultrasound on physicochemical and antioxidant properties of silver carp myofibrillar protein

The present work aimed to evaluate the combined influences of salt sodium chloride (NaCl) concentration and low-frequency ultrasound on the functionality of silver carp myofibrillar protein (MP). Silver carp MP was set using different salt concentrations (0.2, 0.4, 0.6, and 0.8 M NaCl) and low-frequency ultrasound treatment (12 min, 350 W). The samples showed a high solubility (85.30 - 93.80%) across various treatments. The turbidity was lowered significantly by increasing the salt concentration with no sonication, while the turbidity changes were insignificant with the combination treatment (NaCl + U12). Ultrasonic treatment of combined 0.4 M salt (NaCl 0.4 M + U12) achieved the highest water holding capacity (WHC) making up 6.46 g water/g MP. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) inhibition ranged from 16.33 to 43% and 13.27 to 25.69%, respectively, and the highest values were shown in the sample containing 0.4 M salt with sonication (NaCl 0.4 M + U12). It could be concluded that the best treatment was ultrasonic with 0.4 M salt (NaCl 0.4 M + U12). The treatment provided the optimal antioxidant activity with good protein solubility and WHC. The integrated results indicate that employing NaCl with ultrasonic treatments (NaCl + U12) could improve the functionality of silver carp MP. These results are very promising for increasing the potential advantage of this fish species as the sources of proteins for several applications.

Bifunctional Therapeutic Application of Low-Frequency Ultrasound Associated with Zinc Phthalocyanine-Loaded Micelles.

PurposeSonodynamic therapy (SDT) is a new therapeutic modality for the noninvasive cancer treatment based on the association of ultrasound and sonosensitizer drugs. Topical SDT requires the development of delivery systems to properly transport the sonosensitizer, such as zinc phthalocyanine (ZnPc), to the skin. In addition, the delivery system itself can participate in sonodynamic events and influence the therapeutic response. This study aimed to develop ZnPc-loaded micelle to evaluate its potential as a topical delivery system and as a cavitational agent for low-frequency ultrasound (LFU) application with the dual purpose of promoting ZnPc skin penetration and generating reactive oxygen species (ROS) for SDT.MethodsZnPc-loaded micelles were developed by the thin-film hydration method and optimized using the Quality by Design approach. Micelles’ influence on LFU-induced cavitation activity was measured by potassium iodide dosimeter and aluminum foil pits experiments. In vitro skin penetration of ZnPc was assessed after pretreatment of the skin with LFU and simultaneous LFU treatment using ZnPc-loaded micelles as coupling media followed by 6 h of passive permeation of ZnPc-loaded micelles. The singlet oxygen generation by LFU irradiation of the micelles was evaluated using two different hydrophilic probes. The lipid peroxidation of the skin was estimated using the malondialdehyde assay after skin treatment with simultaneous LFU using ZnPc-loaded micelles. The viability of the B16F10 melanoma cell line was evaluated using resazurin after treatment with different concentrations of ZnPc-loaded micelles irradiated or not with LFU.ResultsThe micelles increased the solubility of ZnPc and augmented the LFU-induced cavitation activity in two times compared to water. After 6 h ZnPc-loaded micelles skin permeation, simultaneous LFU treatment increased the amount of ZnPc in the dermis by more than 40 times, when compared to non-LFU-mediated treatment, and by almost 5 times, when compared to LFU pretreatment protocol. The LFU irradiation of micelles induced the generation of singlet oxygen, and the lipoperoxidation of the skin treated with the simultaneous LFU was enhanced in three times in comparison to the non-LFU-treated skin. A significant reduction in cell viability following treatment with ZnPc-loaded micelles and LFU was observed compared to blank micelles and non-LFU-treated control groups.ConclusionLFU-irradiated mice can be a potential approach to skin cancer treatment by combining the functions of increasing drug penetration and ROS generation required for SDT.

Low-frequency ultrasound enhances vascular endothelial growth factor expression, thereby promoting the wound healing in diabetic rats.

Diabetes is a chronic metabolic disease with a high prevalence worldwide, which typically delays or impairs wound healing, potentially causing death. Low-frequency ultrasound treatment promotes the repair of various injuries and may promote wound healing. The aim of the present study was to determine whether low-frequency ultrasound can accelerate wound healing, as well as investigate its effects on the expression of vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β1, interleukin (IL)-6 and tumor necrosis factor (TNF)-α in diabetic rats. A total of 45 Wistar rats were intraperitoneally injected with 1% streptozocin following intraperitoneal injection of pentobarbital sodium anesthesia. Subsequently an incision wound was created in the skin of back. The area of the wound was recorded to calculate the rate of wound healing. The expression of VEGF and TGF-β1 was determined via immunohistochemical analysis and their mRNA and protein levels were measured via reverse transcription-quantitative PCR analysis. The results revealed that when compared with the control group, low-frequency ultrasound treatment significantly increased wound healing rate in diabetic rats and markedly increased the mRNA and protein levels of VEGF and TGF-β1. US treatment also reduced the mRNA and protein levels of TNF-α and IL-6. In conclusion, the results of the present study indicated that low-frequency ultrasound promotes the expression of VEGF and TGF-β1, and inhibits the expression of IL-6 and TNF-α, thereby promoting wound healing in diabetic rats.

Modifying the structure, emulsifying and rheological properties of water-soluble protein from chicken liver by low-frequency ultrasound treatment

The influence of low-frequency ultrasound on the structure, emulsifying and rheological properties of water-soluble protein from chicken liver (CLWP) was investigated. CLWP solutions (10%, w/v) were treated by ultrasound for 4 min at a frequency of 20 kHz (UCLWP, amplitude 50% at an output 100 W, 11.5 W/cm2). The secondary and tertiary structure and thermal denaturation properties were changed in UCLWP. However, SDS-PAGE showed no changes in the subunit compositions between UCLWP and CLWP. Surface hydrophobicity and sulfhydryl groups of UCLWP increased demonstrating partial unfolding of water-soluble proteins and reduced its intermolecular interactions by ultrasound effect. UCLWP showed the smaller and more uniform particles with high-density holes. Furthermore, emulsifying activity index and emulsion stability index of UCLWP had a significant improvement over that of CLWP. UCLWP had lower shear stress and motion resistance during the rheological evaluation. These modifications of the structure, emulsifying and rheological properties for UCLWP could expand the application of chicken liver protein and increase the added value of chicken liver by-products.

КОМПЛЕКСНЫЙ ПОДХОД К ПРОФИЛАКТИКЕ СПАЙКООБРАЗОВАНИЯ БРЮШНОЙ ПОЛОСТИ ПРИ РАСПРОСТРАНЕННОМ ПЕРИТОНИТЕ (ретроспективное исследование)

The aim of the study was to evaluate the effectiveness of complex treatment of peritonitis, including laparoscopic interventions and physiotherapeutic methods, in the prevention of adhesive disease of the abdominal cavity.Methods: The treatment of 120 patients with peritonitis was analyzed. The main group consisted of 50 patients who underwent laparoscopic (closed) abdominal sanitation with the irrigation and aspiration apparatus, followed by low-frequency ultrasound treatment of the abdominal cavity with Mesogel. The control group (n = 70) included patients who used an open method for treating diffuse peritonitis-programmed relaparotomy. Patients were monitored blood levels, endogenous intoxication, microflora composition.results: application of the proposed combined method of treatment of patients with peritonitis leads to normalize the parameters of cardiac activity (pulse), respira- tory organs - the rate of respiration and temperature earlier in comparison with the another group. Evaluation of the dynamics of the main indicators of the generala e-mail: eriken@yandex.rub e-mail: vap.61@yandex.ruc e-mail: nicolai.okunev@yandex.rublood test showed, that the number of leukocytes in the main group quickly comes to normal values. The results of microbiological analysis showed that in the main group the growth of microflora was not detected after the complex therapy, in the remaining patients the number of colony-forming units decreased several times, the sensitivity to antibiotics expanded. The dynamics of the indicators is a marker of therapy effectiveness, that leads to decrease severity of the patients of the main group after the treatment.Conclusion: Using the developed technique in the early postoperative period is noted a significantly better clinical and laboratory effect (more rapid correction of homeostasis disorders). Significant decrease in the formation of adhesions of the abdominal cavity was established. The results obtained make it possible to recom- mend a new method in the treatment of patients with peritonitis.

Microbial effects of part-stream low-frequency ultrasonic pretreatment on sludge anaerobic digestion as revealed by high-throughput sequencing-based metagenomics and metatranscriptomics

BackgroundPart-stream low-frequency ultrasound (LFUS) was one of the common practices for sludge disintegration in full-scale anaerobic digestion (AD) facilities. However, the effectiveness of part-stream LFUS treatment and its effect on AD microbiome have not been fully elucidated.MethodsHere we testified the effectiveness of part-stream LFUS pretreatment by treating only a fraction of feed sludge (23% and 33% total solid of the feed sludge) with 20 Hz LFUS for 70 s. State-of-the-art metagenomic and metatranscriptomic analysis was used to investigate the microbial process underpinning the enhanced AD performance by part-stream LFUS pretreatment.ResultsBy pretreating 33% total solid of the feed sludge, methane yield was increased by 36.5%, while the volatile solid reduction ratio remained unchanged. RNA-seq of the microbiome at stable stage showed that the continuous dosage of easy-degradable LFUS-pretreated feed sludge had gradually altered the microbial community by selecting Bacteroidales hydrolyzer with greater metabolic capability to hydrolyze cellulosic biomass without substrate attachment. Meanwhile, Thermotogales with excellent cell mobility for nutrient capturing was highly active within the community. Foremost proportion of the methanogenesis was contributed by the dominant Methanomicrobiales via carbon dioxide reduction. More interestingly, a perceivable proportion of the reverse electron flow of the community was input from Methanoculleus species other than syntrophic acetate-oxidizing bacteria. In addition, metagenomic binning retrieved several interesting novel metagenomic-assembled genomes (MAGs): MAG-bin6 of Alistipes shahii showed exceptional transcriptional activities towards protein degradation and MAG-bin11 of Candidatus Cloacimonetes with active cellulolytic GH74 gene detected.ConclusionsIn summary, despite the unchanged sludge digestibility, the applied part-stream LFUS pretreatment strategy was robust in adjusting the microbial pathways towards more effective substrate conversion enabled by free-living hydrolyser and beta-oxidation-capable methanogens.

Low frequency ultrasound treatment of palm oil mill effluent for solubilization of organic matter

Low frequency ultrasound treatment of palm oil mill effluent for solubilization of organic matter

Hydrogel increases localized transport regions and skin permeability during low frequency ultrasound treatment

Low frequency ultrasound (LFU) enhances skin permeability via the formation of heterogeneous localized transport regions (LTRs). In this work, hydrogels with different zeta potentials were used as the coupling medium for LFU to investigate their contribution to LTR patterns and to the skin penetration of two model drugs, calcein and doxorubicin (DOX). When hydrogels were used, LTRs covering at least a 3-fold greater skin area were observed compared to those resulting from traditional LFU treatment and sodium lauryl sulfate. More LTRs resulted in an enhancement of calcein skin permeation. The zeta potential of the hydrogels affected the skin penetration of the positively charged DOX; the cationic coupling medium decreased the DOX recovered from the viable epidermis by 2.8-fold, whereas the anionic coupling medium increased the DOX accumulation in the stratum corneum by 4.4-fold. Therefore, LFU/hydrogel treatment increases LTRs areas and can target ionized drugs to specific skin layers depending on the zeta potential of the coupling medium.

Photoactivity under visible light of metal loaded TiO2 catalysts prepared by low frequency ultrasound treatment

Visible-light responsive bare and metal loaded (Pt, Ag, Rh, Pd) TiO2 photocatalysts were prepared by using a simple ultrasound treatment. This method induced bulk oxygen deficiency resulting in a narrowing bandgap (from 3.18 to 3.04eV) and in visible light absorption. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), BET specific surface area (SSA) and pore size distribution (PSD), UV–vis diffuse reflectance spectroscopy (DRS), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the samples was evaluated by using the 4-nitrophenol oxidation reaction and the photocatalytic oxidation of glucose with H2 production. In the presence of the sonicated samples the 4-nitrophenol degradation and the glucose conversion increased of ca. 40% and 11%, respectively. A good H2 evolution was, moreover, observed in the latter case. The Pt-loaded samples showed the highest photoactivity for H2 production and it can be explained by taking into account the highest value of its working function. The obtained results open new perspectives for the synthesis of novel nano-TiO2-based photocatalysts capable to degrade water or airborne pollutants under visible light irradiation.