Hydrodynamic theory of liquid slippage on a solid substrate near a moving contact line

In this Letter a hydrodynamic theory of liquid slippage on a solid substrate near a moving contact line is proposed. A family of spatially varying slip lengths in the Navier slip law recovers the results of past formulations for slip in continuum theories and molecular dynamics simulations and is consistent with well-established experimental observations of complete wetting. This formulation gives a general approach for continuum hydrodynamic theories. New fluid flow behaviors are also predicted yet to be seen in experiment. © 2013 American Physical Society.

Experiences with control of evaporators using extensive vapour bleeding

FOR SUGAR factories with cogeneration plants major changes to the process stations have been undertaken to reduce the consumption of exhaust steam from the turbines and maximise the generated power. In many cases the process steam consumption has been reduced from greater than 52% on cane to ~40% on cane. The main changes have been to install additional evaporation area at the front of the set, operate the pan stages on vapour from No 1 or No 2 effects and undertake juice heating using vapour bleed from evaporators as far down the set as the penultimate stage. Operationally, one of the main challenges has been to develop a control system for the evaporators that addresses the objectives of juice processing rate (throughput) and steam economy, while producing syrup consistently at the required brix and providing an adequate and consistent vapour pressure for the pan stage operations. The cyclic demand for vapour by batch pans causes process disturbances through the evaporator set and these must be regulated in an effective manner to satisfy the above list of objectives for the evaporator station. The impact of the cyclic pan stage vapour demand has been modelled to define the impact on juice rate, steam economy, syrup brix and head space pressures in the evaporators. Experiences with the control schemes used at Pioneer and Rocky Point Mills are discussed. For each factory the paper provides information on (a) the control system used, the philosophy behind the control system and experiences in reaching the current system for control (b) the performance of the control system to handle the disturbances imposed by the pan stage and operate within other constraints of the factory (c) deficiencies in the current system and plans for further improvements. Other processing changes to boost the performance of the evaporators are also discussed.

Nanostructured copper oxide semiconductors : a perspective on materials, synthesis methods and applications

The oxides of copper (CuxO) are fascinating materials due to their remarkable optical, electrical, thermal and magnetic properties. Nanostructuring of CuxO can further enhance the performance of this important functional material and provide it with unique properties that do not exist in its bulk form. Three distinctly different phases of CuxO, mainly CuO, Cu2O and Cu4O3, can be prepared by numerous synthesis techniques including, vapour deposition and liquid phase chemical methods. In this article, we present a review of nanostructured CuxO focusing on their material properties, methods of synthesis and an overview of various applications that have been associated with nanostructured CuxO.

Control and diagnostics of inductively coupled plasmas for chemical vapour deposition of nanocomposite carbon nitride-based films

Control and diagnostics of low-frequency (∼ 500 kHz) inductively coupled plasmas for chemical vapor deposition (CVD) of nano-composite carbon nitride-based films is reported. Relation between the discharge control parameters, plasma electron energy distribution/probability functions (EEDF/EEPF), and elemental composition in the deposited C-N based thin films is investigated. Langmuir probe technique is employed to monitor the plasma density and potential, effective electron temperature, and EEDFs/EEPFs in Ar + N2 + CH4 discharges. It is revealed that varying RF power and gas composition/pressure one can engineer the EEDFs/EEPFs to enhance the desired plasma-chemical gas-phase reactions thus controlling the film chemical structure. Auxiliary diagnostic tools for study of the RF power deposition, plasma composition, stability, and optical emission are discussed as well.

Biolistic transformation of elite indica rice (Oryza sativa L.) cultivars through semi-solid and liquid medium selection systems

Following microprojectile mediated delivery of a plasmid construct (pAHC-25) encoding bar (bialophos resistance) gene into five-day-old scutellar calli derived from mature embryos, the effectiveness of selection procedure for bar-gene expressing tissue was compared for two indica rice cultivars (IR-64 and Karnal Local). While IR-64 transformants could be selected through the generally used semi-solid selection medium, the same procedure was not effective in the basmati cultivar Karnal Local. In the latter case, while lower concentrations (2–4 mg 1−1) of the selective agent phosphinothricin (PPT) yielded only escapes, higher concentrations (6–8 mg l−1) inhibited proliferation of transformed as well as untransformed sectors. For Karnal Local, a liquid medium based selection system was successfully utilized for recovering transformed sectors and, eventually, regenerants. The study demonstrates the generation of transformants of two elite indica cultivars using the environment-independent system of mature embryos from seeds.

Analysis of the extreme diversity of salivary alpha-amylase isoforms generated by physiological proteolysis using liquid chromatography-tandem mass spectrometry

Saliva is a crucial biofluid for oral health and is also of increasing importance as a non-invasive source of disease biomarkers. Salivary alpha-amylase is an abundant protein in saliva, and changes in amylase expression have been previously associated with a variety of diseases and conditions. Salivary alpha-amylase is subject to a high diversity of post-translational modifications, including physiological proteolysis in the oral cavity. Here we developed methodology for rapid sample preparation and non-targeted LC-ESI-MS/MS analysis of saliva from healthy subjects and observed an extreme diversity of alpha-amylase proteolytic isoforms. Our results emphasize the importance of consideration of post-translational events such as proteolysis in proteomic studies, biomarker discovery and validation, particularly in saliva. (C) 2012 Elsevier B.V. All rights reserved.

Collection and determination of nucleotide metabolites in neonatal and adult saliva by high performance liquid chromatography with tandem mass spectrometry

Saliva contains a number of biochemical components which may be useful for diagnosis/monitoring of metabolic disorders, and as markers of cancer or heart disease. Saliva collection is attractive as a non-invasive sampling method for infants and elderly patients. We present a method suitable for saliva collection from neonates. We have applied this technique for the determination of salivary nucleotide metabolites. Saliva was collected from 10 healthy neonates using washed cotton swabs, and directly from 10 adults. Two methods for saliva extraction from oral swabs were evaluated. The analytes were then separated using high performance liquid chromatography (HPLC) with tandem mass spectrometry (MS/MS). The limits of detection for 14 purine/pyrimidine metabolites were variable, ranging from 0.01 to 1.0 mu M. Recovery of hydrophobic purine/pyrimidine metabolites from cotton tips was consistently high using water/acetonitrile extraction (92.7-111%) compared with water extraction alone. The concentrations of these metabolites were significantly higher in neonatal saliva than in adults. Preliminary ranges for nucleotide metabolites in neonatal and adult saliva are reported. Hypoxanthine and xanthine were grossly raised in neonates (49.3 +/- 25.4; 30.9 +/- 19.5 mu M respectively) compared to adults (4.3 +/- 3.3; 4.6 +/- 4.5 mu M); nucleosides were also markedly raised in neonates. This study focuses on three essential details: contamination of oral swabs during manufacturing and how to overcome this; weighing swabs to accurately measure small saliva volumes; and methods for extracting saliva metabolites of interest from cotton swabs. A method is described for determining nucleotide metabolites using HPLC with photo-diode array or MS/MS. The advantages of utilising saliva are highlighted. Nucleotide metabolites were not simply in equilibrium with plasma, but may be actively secreted into saliva, and this process is more active in neonates than adults. (C) 2013 Elsevier B.V. All rights reserved.

Identification of salivary N-glycoproteins and measurement of glycosylation site occupancy by boronate glycoprotein enrichment and liquid chromatography/electrospray ionization tandem mass spectrometry

RATIONALE Diseases including cancer and congenital disorders of glycosylation have been associated with changes in the site-specific extent of protein glycosylation. Saliva can be non-invasively sampled and is rich in glycoproteins, giving it the potential to be a useful biofluid for the discovery and detection of disease biomarkers associated with changes in glycosylation. METHODS Saliva was collected from healthy individuals and glycoproteins were enriched using phenylboronic acid based glycoprotein enrichment resin. Proteins were deglycosylated with peptide-N-glycosidase F and digested with AspN or trypsin. Desalted peptides and deglycosylated peptides were separated by reversed-phase liquid chromatography and detected with on-line electrospray ionization quadrupole-time-of-flight mass spectrometry using a 5600 TripleTof instrument. Site-specific glycosylation occupancy was semi-quantitatively determined from the abundance of deglycosylated and nonglycosylated versions of each given peptide. RESULTS Glycoprotein enrichment identified 67 independent glycosylation sites from 24 unique proteins, a 3.9-fold increase in the number of glycosylation sites identified. Enrichment of glycoproteins rather than glycopeptides allowed detection of both deglycosylated and nonglycosylated versions of each peptide, and thereby robust measurement of site-specific occupancy at 21 asparagines. Healthy individuals showed limited biological variability in occupancy, with partially modified sites having characteristics consistent with inefficient glycosylation by oligosaccharyltransferase. Inclusion of negative controls without enzymatic deglycosylation controlled for spontaneous chemical deamidation, and identified asparagines previously incorrectly annotated as glycosylated. CONCLUSIONS We developed a sample preparation and mass spectrometry detection strategy for rapid and efficient measurement of site-specific glycosylation occupancy on diverse salivary glycoproteins suitable for biomarker discovery and detection of changes in glycosylation occupancy in human disease.

Influence of semiconducting properties of nanoparticle coating on the electrochemical actuation of liquid metal marble

Semiconducting properties of nanoparticle coating on liquid metal marbles can present opportunities for an additional dimension of control on these soft objects with functional surfaces in aqueous environments. We show the unique differences in the electrochemical actuation mechanisms of liquid metal marbles with n- and p-type semiconducting nanomaterial coating. A systematic study on such liquid metal marbles shows voltage dependent nanoparticle cluster formation and morphological changes of the liquid metal core during electrochemical actuations and these observations are unique to p-type nanomaterial coated liquid metal marbles.

Comparison of nanostructures obtained from galvanic replacement in water and an ionic liquid for applications in electrocatalysis and SERS

We demonstrate potential applications for unusual dendrite like Au–Ag alloy nanoparticles formed via a galvanic replacement reaction in the ionic liquid [BMIM][BF4]. In comparison to Au–Ag alloy nanoshells synthesised via a similar reaction in water, the unusual branched structure of the dendritic materials led to increased electrocatalytic activity for the oxidation of both formaldehyde and hydrazine, and increased sensitivity and spectral resolution for the surface enhanced Raman scattering (SERS) of 4,4-bipyridal.