Mild Ultrasonication Research Articles

Mild Sonication Accelerates Ethanol Production by Yeast Fermentation

Ethanol is a renewable and environmentally benign substitute for the current fossil-fuel-based transportation fuels. Fermentation of sugars, which is, in general, a slow process, is an essential step in the production of ethanol from renewable sources. This paper reports a successful attempt to accelerate the well-known sugar fermentation process by applying soft sonication. Fermentation of glucose was carried out using Saccharomyces cerevisiae under continuous mild ultrasonication conditions. The kinetics of the fermentation reaction was monitored by 13C nuclear magnetic resonance spectroscopic analysis and weight loss measurements of the fermentation broth. The reaction rate constant was enhanced by 2.3 ± 0.2 and 2.5 ± 0.2 times as a result of sonication at 30 and 20 °C, respectively, as compared to a stirred reaction, and was about 10 times faster than non-stirred fermentation. The acceleration in the fermentation of glucose was observed for both 20 and 40 wt % concentrations of the glucose solution.

Preparation of aqueous dispersions of coenzyme Q10 nanoparticles with amylomaize starch and its dextrin

An aqueous dispersion of CoQ10 nanoparticles could be prepared by using amylomaize starch or its dextrin (average DP 311). CoQ10 (100 mg dry solids) was dispersed in aqueous starch or dextrin solution (500 mg/5 mL) at 60–80 °C for 3 days, and then the solids were isolated by centrifuging in the dispersion (25,000×g, 30 min). The isolated particles consisted of CoQ10 and starch at an approximate weight ratio of 2:1. The presence of V-amylose complex with CoQ10 was confirmed under differential scanning calorimetery (DSC), but most of the CoQ10 in the particles existed as crystalline aggregates. The isolated particles, initially ranged in micrometer, could be re-dispersed in water at nano-sizes by treating with a mild ultrasonication. The aqueous dispersions of CoQ10 nanoparticles (100 mg/100 g) exhibited zeta potentials of −33.9 and −51.1 mV, respectively for starch and dextrin dispersions, and remained homogeneous for more than 3 weeks without forming precipitates during an ambient storage.

Functionalization and Dispersion of Hexagonal Boron Nitride (h‐BN) Nanosheets Treated with Inorganic Reagents

A mixture of bulk hexagonal boron nitride (h-BN) with hydrazine, 30% H(2)O(2), HNO(3)/H(2)SO(4), or oleum was heated in an autoclave at 100 °C to produce functionalized h-BN. The product formed stable colloid solutions in water (0.26-0.32 g L(-1)) and N,N-dimethylformamide (0.34-0.52 g L(-1)) upon mild ultrasonication. The yield of "soluble" h-BN reached about 70 wt%. The dispersions contained few-layered h-BN nanosheets with lateral dimensions in the order of several hundred nanometers. The functionalized dispersible h-BN was characterized by IR spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV/Vis spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). It is shown that h-BN preserves its hexagonal structure throughout the functionalization procedure. Its exfoliation into thin platelets upon contact with solvents is probably owing to the attachment of hydrophilic functionalities.

Supergrowth of Aligned Carbon Nanotubes Directly on Carbon Papers and Their Properties as Supercapacitors

We demonstrate that vertically aligned carbon nanotubes can be synthesized directly on conductive carbon papers and used as excellent electrochemical capacitors. The carbon nanotubes were synthesized with use of an Al/Fe catalyst via water-assisted chemical vapor deposition. They grew as fast as ∼100 μm/min and approximately 70% of them had double walls with an average diameter of ∼6 nm. Interestingly, the carbon nanotube forest showed microscale patterns defined by the structure of underlying carbon papers. The nanotubes were attached well to the carbon papers and maintained their adhesion under mild ultrasonication in solution. Owing to the direct integration, naturally patterned structure, and good alignment, the carbon nanotubes showed excellent performance as supercapacitors. In aqueous 1 M H2SO4 solution, specific capacitance, energy, and power measured at the current density of 20 A/g were ca. 200 F/g, 20 Wh/kg, and 40 kW/kg, respectively. A specific energy of >100 Wh/kg was achieved when organic e...

Cationic surfactant mediated exfoliation of graphite into graphene flakes

A simple and effective method for the preparation of a few layered graphene nanoflakes directly from graphite has been successfully demonstrated. Mild ultrasonication of highly ordered pyrolytic graphite, in presence of a cationic surfactant cetyltrimethylammonium bromide and acetic acid yielded graphene nanoflakes, which formed a stable colloidal suspension in organic solvent such as N,N-dimethyl formamide. Scanning and transmission electron microscopic analyses showed that the dispersed phase consist of mainly few layered graphene nanoflakes. Average thickness of the flakes was found to be ∼1.18 nm. Energy dispersive X-ray analysis indicated the absence of graphene oxide. Field emission measurements for the nanoflakes showed a turn on voltage of 7.5 V/μm and emission current densities of 0.15 mA/cm 2.

Formation of various TiO2 nanostructures from electrochemically anodized titanium

TiO2nanostructures, including nanowires, highly ordered nanotube arrays, and single crystalline nanoplates, were obtained from electrochemically anodized Ti foil in a fluorine-containing ethylene glycol electrolyte. The TiO2nanowires, formed by the electric field induced chemical splitting of TiO2nanotubes by fluoride ions during a lengthy anodization can be isolated from the nanotube arrays by mild ultrasonication. The highly ordered TiO2nanotubes buried underneath are thus exposed. The transformation of as-prepared amorphous TiO2nanotubes into the anatase or rutile phase as a function of annealing temperature was systematically scrutinized by Raman spectroscopic measurements in conjunction with TEM imaging. In the latter study, the ultramicrotomed sections of the samples clearly exhibited the formation of highly crystalline TiO2. More importantly, crystalline TiO2nanotubes were mechanically broken into intriguing single crystalline TiO2 nanoplates as a result of ultramicrotoming. The present study not only demonstrates a facile approach to produce high quality TiO2nanowires, nanotubes, and nanoplates in a simple manner, but also provides valuable insights into temperature dependent crystalline transformation in the anodic TiO2nanotube arrays.

Pollen‐mediated transformation of Sorghum bicolor plants

Pollen from sorghum (Sorghum bicolor L. Moench) were transformed by a novel genetic transformation approach using mild ultrasonication. The plasmid pBI121 contained the NPT II gene encoding NPT II (neomycin phosphotransferase II) and a GUS (beta-glucuronidase) reporter gene. Plasmid DNA and pollen from sorghum A(2)V4B were submerged in a 0.3 mol/l sucrose solution and then subjected to ultrasonication. The treated pollen was then used for pollination of stigmas from the male sterile line A(2)V4A. Detection of transient and stable GUS activity confirmed that the GUS gene was expressed in transgenic plants. PCR amplification and Southern-blot analysis of transgenic plants confirmed that the NPT II gene had been integrated into the sorghum genome. These results indicate that direct gene transfer to pollen can be mediated by mild ultrasonication.

Recovery of transgenic plants by pollen-mediated transformation in Brassica juncea

The aroA-M1 encoding the mutant of 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) was introduced into the Brassica juncea genome by sonication-assisted, pollen-mediated transformation. The plasmid DNA and collected pollen grains were mixed in 0.3 mol/L sucrose solution and treated with mild ultrasonication. The treated pollen was then pollinated onto the oilseed stigmas after the stamens were removed artificially. Putative transgenic plants were obtained by screening germinating seeds on a medium containing glyphosate. Southern blot analysis of glyphosate-resistant plants indicated that the aroA-M1 gene had been integrated into the oilseed genome. Western blot analysis further confirmed that the EPSPS coded by aroA-M1 gene was expressed in transgenic plants. The transgenic plants exhibited increased resistance to glyphosate compared to untransformed plants. Some of those transgenic plants had considerably high resistance to glyphosate. The genetic analysis of T1 progeny further confirmed that the inheritance of the introduced genes followed the Mendelian rules. The results indicated that foreign genes can be transferred by pollen-mediated transformation combined with mild ultrasonication.

Identification of bacteria on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties by 16S rRNA gene sequencing and by microbiological culture

It has been postulated that bacteria attached to the surface of prosthetic hip joints can cause localised inflammation, resulting in failure of the replacement joint. However, diagnosis of infection is difficult with traditional microbiological culture methods, and evidence exists that highly fastidious or non-cultivable organisms have a role in implant infections. The purpose of this study was to use culture and culture-independent methods to detect the bacteria present on the surface of prosthetic hip joints removed during revision arthroplasties. Ten consecutive revisions were performed by two surgeons, which were all clinically and radiologically loose. Five of the hip replacement revision surgeries were performed because of clinical infections and five because of aseptic loosening. Preoperative and perioperative specimens were obtained from each patient and subjected to routine microbiological culture. The prostheses removed from each patient were subjected to mild ultrasonication to dislodge adherent bacteria, followed by aerobic and anaerobic microbiological culture. Bacterial DNA was extracted from each sonicate and the 16S rRNA gene was amplified with the universal primer pair 27f/1387r. All 10 specimens were positive for the presence of bacteria by both culture and PCR. PCR products were then cloned, organised into groups by RFLP analysis and one clone from each group was sequenced. Bacteria were identified by comparison of the 16S rRNA gene sequences obtained with those deposited in public access sequence databases. A total of 512 clones were analysed by RFLP analysis, of which 118 were sequenced. Culture methods identified species from the genera Leifsonia (54.3%), Staphylococcus (21.7%), Proteus (8.7%), Brevundimonas (6.5%), Salibacillus (4.3%), Methylobacterium (2.2%) and Zimmermannella (2.2%). Molecular detection methods identified a more diverse microflora. The predominant genus detected was Lysobacter, representing 312 (60.9%) of 512 clones analysed. In all, 28 phylotypes were identified: Lysobacter enzymogenes was the most abundant phylotype (31.4%), followed by Lysobacter sp. C3 (28.3%), gamma proteobacterium N4-7 (6.6%), Methylobacterium SM4 (4.7%) and Staphylococcus epidermidis (4.7%); 36 clones (7.0%) represented uncultivable phylotypes. We conclude that a diverse range of bacterial species are found within biofilms on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties.

Evaluation of Nonculture Methods for the Detection of Prosthetic Hip Biofilms

Authors of previous studies have found that culture-based detection of prosthetic hip infections can be improved by adherence to strict anaerobic protocols and mild ultrasonication of retrieved prostheses to remove bacteria growing as an adherent biofilm. Furthermore, direct analyses of sonicate samples by immunofluorescence microscopy (with genus-specific and species-specific monoclonal antibodies or polyclonal antisera) produces significantly greater and more rapid detection rates for infection compared with culture alone. Despite its diagnostic value within a research setting, the practical advantages and limitations of immunofluorescence microscopy for a busy diagnostic laboratory needs consideration. In addition, the method must be evaluated against other nonculture-based techniques that may prove more appropriate. In this review, we describe how immunofluorescence microscopy presents an attractive and reliable method for routine detection of prosthetic hip biofilms compared, primarily, to polymerase chain reaction, although other nonculture methods of diagnosis based on fluorescent in situ hybridization and serologic analysis are considered. We describe how the immunofluorescence microscopy technique is robust, relatively simple and, in contrast to broad-range 16S recombinant-deoxyribonucleic-acid-based polymerase chain reaction, does not require a separate clean-room facility or strict adherence to aseptic techniques. More importantly we highlight how dislodged biofilm, which appears as large aggregates of bacteria, easily can be identified from skin contaminants that occur as single cells or small aggregates of only a few cells.

Hydrophilic and Water-Soluble Poly(ferrocenylsilanes)

The synthesis of a series of novel hydrophilic and water-soluble neutral and cationic high molecular weight poly(ferrocenylsilanes) is reported. The dichlorosilyl-bridged [1]ferrocenophane Fe(η-C5H4)2SiCl2 (3) was reacted with various polyether alcohols in the presence of Et3N as an HCl acceptor to afford the monomers Fe(η-C5H4)2Si(OR)2 (4: R = CH2CH2OCH3; 5: R = CH2CH2OCH2CH2OCH3). Using ambient temperature transition-metal catalyzed ring-opening polymerization of these monomers, hydrophilic poly(ferrocenylsilanes) were obtained. Transition-metal catalyzed ring-opening polymerization of the silicon-bridged [1]ferrocenophane Fe(η-C5H4)2SiMeCl (8) afforded the corresponding polymer [Fe(η-C5H4)2SiMeCl]n (9). Replacement of the chlorine substituents of 9 was achieved using (a) poly(ethylene glycol) methyl ether, Mn = 350, in the presence of Et3N to afford the poly(ferrocenylsilane) [Fe(η-C5H4)2SiMe(OCH2CH2)xOCH3]n (x ∼ 8: 10a: Mn ∼ 56 000; 10b: Mn ∼ 189 000) and (b) N,N-dimethylethanolamine to afford [Fe(η-C5H4)2SiMe(OCH2CH2NMe2)]n (11). Quaternization of polymer 11 with MeI or HCl afforded the polyelectrolytes [Fe(η-C5H4)2SiMe(OCH2CH2NMe3I)]n (12) and [Fe(η-C5H4)2SiMe(OCH2CH2NMe2HCl)]n (13). Poly(ferrocene) 10b dissolved in water to give a clear solution whereas 10a, 12, and 13 afford slightly cloudy solutions. Lower critical solution temperatures (LCST) for 10a and 10b were determined to be 38 and 46 °C, respectively. Investigations by dynamic light scattering and centrifugation experiments indicated the presence of aggregates. In the case of 12 the larger aggregates could be partially broken up using mild ultrasonication but re-form over time. Clear solutions of the polymers 10a, 12, and 13 in water can be easily prepared by microfiltration techniques.

42] Detection of prosthetic joint biofilm infection using immunological and molecular techniques

Publisher Summary This chapter describes how the detection of bacteria by culture from revision hip prostheses can be improved by employing strict anaerobic techniques and by using mild ultrasonication to dislodge bacteria adhering to the surface of the retrieved implants. Nonculture techniques that can be used to further improve the detection of infection, including examination of the inflammatory response in implant-associated tissue and the detection of bacteria using immunological and polymerase chain reaction (PCR)-based molecular approaches, are also described. The use of strict anaerobic techniques and mild ultrasonication has resulted in bacteria being cultured from 26 of 120 (22%) retrieved implants examined. The use of nonculture techniques to improve the detection of prosthetic joint biofilm infection coupled with appropriate postoperative antibiotic therapy should improve the clinical outcome for patients undergoing revision hip surgery.

Improved detection of infection in hip replacements. A currently underestimated problem.

Our aim was to determine if the detection rate of infection of total hip replacements could be improved by examining the removed prostheses. Immediate transfer of prostheses to an anaerobic atmosphere, followed by mild ultrasonication to dislodge adherent bacteria, resulted in the culture of quantifiable numbers of bacteria, from 26 of the 120 implants examined. The same bacterial species were cultured by routine microbiological techniques from only five corresponding tissue samples. Tissue removed from 18 of the culture-positive implants was suitable for quantitative tissue pathology and inflammatory cells were present in all samples. Furthermore, inflammatory cells were present in 87% of tissue samples taken from patients whose implants were culture-negative. This suggests that these implants may have been infected by bacteria which were not isolated by the techniques of culture used. The increased detection of bacteria from prostheses by culture has improved postoperative antibiotic therapy and should reduce the need for further revision.

Improved detection of infection in hip replacements

Our aim was to determine if the detection rate of infection of total hip replacements could be improved by examining the removed prostheses. Immediate transfer of prostheses to an anaerobic atmosphere, followed by mild ultrasonication to dislodge adherent bacteria, resulted in the culture of quantifiable numbers of bacteria, from 26 of the 120 implants examined. The same bacterial species were cultured by routine microbiological techniques from only five corresponding tissue samples. Tissue removed from 18 of the culture-positive implants was suitable for quantitative tissue pathology and inflammatory cells were present in all samples. Furthermore, inflammatory cells were present in 87% of tissue samples taken from patients whose implants were culture-negative. This suggests that these implants may have been infected by bacteria which were not isolated by the techniques of culture used. The increased detection of bacteria from prostheses by culture has improved postoperative antibiotic therapy and should reduce the need for further revision.

A morphology index for characterization of cell shape in Candida albicans.

The morphology of Candida albicans cells was determined from their maximum length, maximum diameter and septal diameter in a mathematical ratio, the morphology index (Mi), which usually ranged from approximately 1 for spherical yeast cells to approximately 4 for true hyphae, with elongated yeast cells and pseudohyphae giving intermediate values. Mi could be determined with high reproducibility for C. albicans grown in a variety of environments. The highest mean Mi was seen with cells grown in serum and Eagle's medium at 37 degrees C, the lowest with cells grown in Sabouraud glucose broth at 26 degrees C. Variant strains of C. albicans gave Mi values that remained constant in a variety of growth environments. The Mi facilitated detection of two variants that grew exclusively in the yeast form, one that grew as elongated yeasts but could be induced to form pseudohyphae in serum, and one consistently pseudohyphal variant. Cells with a mean Mi up to 2.5 could be easily separated at septal junctions by mild ultrasonication, whereas cells with a mean Mi greater than 3.5 tended not to separate under these conditions. The chitin content of C. albicans cells was almost twice as great in cells with a Mi approaching 4 as in cells with a Mi close to 1. The wide range of Mi distributions for a single C. albicans isolate in different environments demonstrates that the fungus does not undergo abrupt changes of morphological phase: rather there are continual changes in morphology between spherical yeasts and true hyphae at the extremes. The study shows that Mi can be used reliably in place of subjective descriptions of morphology to indicate the shape of a C. albicans cell. It should facilitate the detection of molecular and cellular markers specific for morphogenesis in the fungus.

Preparative isolation of Apo(Ca2+-ATPase) from sarcoplasmic reticulum and the reactivation by lysophosphatidylcholine of Ca2+-dependent ATP hydrolysis and partial-reaction steps of the enzyme.

1. A preparative method for the isolation of the lipid free apoprotein, the Ca2+-ATPase of sarcoplasmic reticulum, from the partially purified lipoprotein, Ca2+-ATPase vesicles, is presented. 2. By enzymatic hydrolysis of the phospholipids and removal of the splitting products and endogenous neutral lipids, the apoprotein was consistently delipidated to 0.02 mumol Pi/mg protein. 3. Reactivation of the splitting of ATP and the pseudo substrate, dinitrophenyl phosphate, was demonstrated with a variety of lipids and detergents. 4. A total reactivation of ATP splitting was achieved after a mild ultrasonication of the apoprotein with myristoylglycerophosphocholine which resulted in solubilization of the enzyme as an optically clear solution. 5. The stable resolubilized enzyme could be stored for several weeks maintaining full enzymatic activity. Gel chromatography suggested that under the assay conditions, the monomeric form of the enzyme predominated. 6. In comparison with the native enzyme, the resolubilized enzyme showed differences in the temperature dependence of the activation of ATP hydrolysis and a reduced apparent affinity for MgATP. 7. The phosphate-transferring activities of the resolubilized enzyme were only partially reactivated in the forward direction, and none of the reverse partial-reaction steps of the enzyme could be demonstrated.