Reproducibility Of Application Research Articles

Synthesis, functionalization and assembly of monodisperse gold nanoparticles with potassium sodium tartrate as reducing agent

AbstractMonodisperse gold nanoparticles (AuNPs) are an important guarantee of their scientific value and technical reproducibility in applications. The tartrate has a similar molecule structure and physicochemical properties to citrate, bur is much less reducibility and is usually not favorable for the formation of monodisperse AuNPs. We have prepared monodisperse AuNPs with tartrate (potassium sodium tartrate) as reducing and capping agent. Various parameters affecting the monodisperse properties during the preparation of tartrate‐capped AuNPs were analyzed, such as reversing the order of reactant addition and ripening of seeds, while adjusting the synthesis parameters such as time, temperature, and pH value. The final results show that the addition of a trace amount of silver (Ag) ion into chloroauric acid, the monodispersed tartrate‐capped AuNPs can be obtained with the size range of 9–40 nm. The fabricated gold seeds and grown tartrate‐capped AuNPs have narrow size dispersions (or polydispersity, σ<10 %). The minimum size dispersion of AuNPs with twice growth steps was as low as 5.73 %. So, the weak reducing agent of tartrate is one of good candidates to synthesize the monodispersity of AuNPs. Additionally, tartrate‐capped AuNPs have good stability and can be easily modified and form a large two‐dimensional (2D) monolayer nanostructure film.

Improving the electrochemical properties of Ti3C2Tx MXene for H2S electrochemical sensor by calcination

The existence level and metabolic mechanism of hydrogen sulfide (H2S) have been proved to have an important impact on organisms, even affecting the generation and development of many neurological diseases. Therefore, it is essential to develop sensitive and accurate H2S sensors to detect H2S concentration at trace level and provide effective research tools for studying the mechanism of action of H2S on organisms. MXene is a class of two-dimensional transition metal carbonitrides with a graphene-like structure, which indicating great application prospects as a biosensor due to its large specific surface area and good conductivity. In this work, the properties of multilayer Ti3C2Tx MXene materials are optimized concerning their physical structure and functional groups. Based on the Li + intercalation method, SL-Ti3C2Tx MXene is prepared by a mild route, and its electrochemical performance is optimized by high temperature calcination under high purity argon conditions. The change in material properties at high temperature is discussed through structural and chemical analysis, and the optimal calcination temperature is determined to be 700 °C. The constructed H2S electrochemical sensor exhibits high stability and reproducibility in applications, with a detection range of 0.1–500 μM, and the detection limit is reduced to 5.77 nM.

Multicolor emitting luminescent MgO nanocubes for implication in ratiometric optical thermometry

Optical thermometry employing dual emission from two distinct wavelengths for sensing performances has advantages over conventional thermometers due to the self-reference and noninvasive mode of operation. Here, we have demonstrated the synthesis of the multiple colors emitting luminescent MgO nanocubes and explored their temperature-dependent tunable emissions for application in intensity ratio-based optical thermometry. MgO nanocubes are prepared by heating Mg metal ribbons at different temperatures in air ambient. The as-prepared nanocubes exhibit two distinguished photoluminescence emission bands under UV (355 nm) and visible (532 nm) excitations. An excitation and synthesis condition-dependent multicolor emissions are observed in the visible to NIR regions due to the presence of various intermediate defect levels within the band gap of the materials. A temperature-dependent tunable dual emission is realized for different nanocubes, where the two peaks respond to the applied temperature differently, forming an isosbestic point. The difference in the temperature dependency of the two peaks is essential for the fluorescence intensity ratio-based optical thermometry application. The reason for the different responses of the two peaks is explained depending on the presence of the defect levels. From the temperature-dependent intensity ratio variation of MgO nanocubes, the highest sensitivity value of 6.79% K − 1 is achieved, which is very high compared to the various reported ratiometric sensors. The MgO nanocubes demonstrate better stability and reproducibility for application in the 83–513 K wide temperature range.

Challenges in Pathologic Staging of Bladder Cancer: Proposals for Fresh Approaches of Assessing Pathologic Stage in Light of Recent Studies and Observations Pertaining to Bladder Histoanatomic Variances.

The paradigm of pathologic stage (pT) categorization in bladder cancer remains the depth of invasion into the different histologic layers of the bladder wall. However, the approaches to assigning pT stage category toward an enhanced outcome stratification have been marked by challenges and innovations, due in part to our growing appreciation of the surprisingly perplexing bladder histoanatomy. Upstaging of pT1 tumors after radical cystectomy is substantial and underscores the potential value of pT1 substaging in transurethral resection (TUR) specimens. The 2017 American Joint Committee on Cancer tumor-node-metastasis system recommends pT1 substaging but recognizes the need to optimize the approach. Over the years, the cut-off for microinvasion has been significantly lowered to 0.5 mm and is now a promising scheme for pT1 (micrometric) substaging. Unlike the micrometric approach, histoanatomic substaging using muscularis mucosae (MM) and vascular plexus as landmarks is less feasible in TUR specimens and inconsistent in stratifying the outcome of pT1 tumors. The lamina propria possesses inherent variations in depth, MM, and vascular plexus dispositions that should be factored in future pT1 substaging proposals. Histoanatomic variations among the bladder regions also occur, and studies suggest that trigone and bladder neck cancers may have more adverse outcomes. The muscularis propria (MP), besides being the essential histologic landmark for assigning pT2 stage category, is also considered a surrogate for the adequacy of TUR, furthering the importance of identifying its presence in TUR specimens. MP, however, may be mimicked by hyperplastic or isolated MP-like MM muscle bundles in the lamina propria with overstaging implications, and caution should be exercised in distinguishing these 2 muscle types morphologically and immunohistochemically. Presence of additional superficial MP unique from the detrusor muscle proper may also complicate staging at the trigone and ureter insertion sites. With regard to the depth of MP invasion, large and multicenter studies have reaffirmed the prognostic significance of pT2a/b subcategories. It is revealed that there are at least 3 ways used to demarcate the irregular MP to perivesical soft tissue junction, and use of a common criterion indicates improvement in pT2b/pT3a staging reproducibility. Although studies have shown significantly poorer outcome in pT3b compared with pT3a tumors, this designation has a substantial reliance on the prosector's gross assessment of perivesical soft tissue invasion which if performed incorrectly may lead to staging inaccuracy of pT3 tumors. The 8th edition of the American Joint Committee on Cancer has updated the staging schema for bladder cancers with concomitant prostatic stromal invasion and cancers within bladder diverticula. Because of 2 possible pT designations, prostatic stromal invasion in TUR specimens should not be automatically staged as either pT4a or pT2 (urethral). Recent data support that bladder cancer invading into the seminal vesicle has comparable outcome to pT4b tumors. Interestingly, several studies in pT4a tumors, which are staged based on sex-specific organs, have shown poorer outcome in females than males after radical cystectomy, and while there are possibly several reasons, they may also include anatomic factors. Despite the progress has been made, work remains to be done to inform future bladder cancer pT category definitions and their reproducibility in application and prognostication.

Multi-ion and pH sensitivity of AgGeSe ion selective electrodes

Many chalcogenide glasses have been found to combine benefits such as good chemical durability, selectivity, and reproducibility for applications as solid-state sensitive membranes of ion selective electrodes (ISEs). In previous works, we have shown that ISEs with ionic conductive AgGeSe membranes have good sensitivity to Ag+ ions. In the present work, we explore the Agx(Ge0.25Se0.75)100−x, 10≤x≤30 (at%) system as candidate for ISEs applications detecting several other ions (K+, Mg2+, Cr3+, Fe3+, Ni2+, Cd2+, Hg2+, and Pb2+). We evaluated ISEs fabricated with bulk as well as with thin film membranes. We found no dependence of the sensing properties on the Ag content of the ionic conductive membranes. Thin films exhibited the same properties than bulk membranes, indicating that these chalcogenide glasses have great potential for miniaturization. The ISEs showed a high response (Nernstian or super-Nernstian) to the presence of Hg2+, Pb2+, and Fe3+, a low response (sub-Nernstian) to the presence of Cr3+, and a total lack of response to the presence of Cd2+, Ni2+, Mg2+, and K+. We also tested how the pH of the solution affected the response of the ISEs. The potentials of the ISEs were practically constant in neutral or acidic solutions, while decreased drastically in basic solutions when the primary ion was not present. The latter phenomenon was caused by the slow dissolution of the membrane into the solution, meaning that long-term basic environments should be avoided for these ISEs. We concluded that ISEs with ionic conductive AgGeSe membranes are good candidates to integrate multi-electrode systems.

Assessment of palatal rugae pattern and their reproducibility for application in forensic analysis

Background:Rugae are the anatomical folds that are located on the anterior third of palate behind the incisive papillae. They are also known as “Plica palatine,” and the study of these patterns is called palatoscopy. It can be used in various fields such as sex determination, orthodontics and forensic odontology.Objective:To investigate palatal rugae patterns in females and males and to evaluate the stability of these patterns in pre- and post-operative orthodontic cases.Materials and Methods:Fifty patients were selected for this study (25 males and 25 females). From the above sample, 10 males and 10 females had undergone orthodontic treatment and their casts were retrieved for sex determination analysis and stability of rugae patterns pre- and post-treatment.Results:Changes occur in bony structures during fixed orthodontic treatment but rugae patterns remain stable. Kappa stats and Chi square test were used to analyze agreement between the two evaluators, and 95% correct matches were achieved.Conclusion:Palatal rugae are unique to every individual and can be used as an indicator in forensic odontology.

The Preparation of Magnetic Iron Oxide Nanoparticles in Microreactors

Abstract The preparation of magnetic iron oxide nanoparticles within microreactors is reported. The proportion of γ-Fe2O3 and Fe3O4 in the sample was determined, an important parameter for reproducibility in applications.

Optoelectronic surface-related properties in boron-doped and irradiated diamond thin films

Elucidation of microscopic properties of synthetic diamond films, such as formation and evolution of bulk and surface defects, chemistry of dopants, is necessary for a reliable quality control and reproducibility in applications. Surface photovoltage (SPV) spectroscopy and photoluminescence (PL) spectroscopy were employed to study diamond thin films grown on silicon by microwave plasma-assisted chemical vapor deposition and hot-filament chemical vapor deposition with different levels of boron doping in conjunction with gamma irradiation. SPV experiments showed that while the increase of boron concentration leads to a semiconductor-metal transition, subsequent gamma irradiation reverts quasi-metallic samples back to a semiconducting state by compensating electrical activity of boron possibly via hydrogen. One of the most pronounced common transitions observed at ∼3.1–3.2 eV in the SPV spectra was also present in all of the PL spectra. It is likely that this is a signature of the sp2-hybridized carbon clusters in or in the vicinity of grain boundaries.

Microwave-assisted solvent extraction of solid matrices and subsequent detection of pharmaceuticals and personal care products (PPCPs) using gas chromatography–mass spectrometry

Concentrations of pharmaceuticals and personal care products (PPCPs) in natural solids remain largely unknown. Contributing to this, is a lack of methods permitting the simultaneous detection of the diverse, low-level contaminants present in these complex matrices. We have developed a microwave-assisted solvent extraction (MASE)-based method targeting seven diverse PPCPs (caffeine, 17β-estradiol, ibuprofen, ketoprofen, musk ketone, naproxen, and triclosan) and a molecular marker for fecal waste (epicoprostanol). The method consisted of optimizing the following variables: derivatization of the polar target analytes, silica gel open column clean-up, and gas chromatographic–mass spectrometric (GC–MS) analysis of sample extracts for analysis and detection of the compounds noted above. Testing of the method on spiked soil allowed for 89.6 ± 2.89% recovery of three target compounds and 25.0 ± 1.93% recovery of five of the compounds. Although the latter recoveries were low, the precision across all recoveries was high, suggesting good reproducibility in application of the method. Furthermore, we suspect that matrix effects are likely responsible for the lower recoveries. Techniques with the exclusive incorporation of organic solvents were found inapplicable in the study of a pharmaceutical salt, diphenhydramine HCl. Application of the developed method to sediment collected directly downstream of the effluent pipe of a wastewater treatment plant allowed detection of ibuprofen, naproxen, ketoprofen, and epicoprostanol at ng–μg per gram dry weight concentrations. The observation of acidic pharmaceuticals, previously believed to exhibit insignificant sorption to solid matrices, in the tested sediment samples, coupled with application of biosolids for agricultural purposes, demonstrates the need for expanded investigation of PPCP contamination of natural solid matrices.

Computational model for nonlinear plasma formation in high NA micromachining of transparent materials and biological cells

Cell surgery based on ultrashort laser pulses is a fast evolving field in biophotonics. Noninvasive intra cellular dissection at sub-diffraction resolution can be performed within vital cells with very little hazardous effects to adjacent cell organelles. Microscope objectives of high numerical aperture (NA) are used to focus ultrashort pulses to a small spot. Due to the high order of nonlinearity, plasma formation and thus material manipulation is limited to the very focus. Nonetheless nonlinear plasma formation is generally accompanied by a number of additional nonlinear effects like self-focusing and filamentation. These parasitic effects limit the achievable precision and reproducibility of applications. Experimentally it is known that the intensity of these effects decreases with increasing NA of the focusing optics, but the process of nonlinear plasma formation at high NA has not been studied numerically in detail yet. To simulate the interaction of ultrashort laser pulses with transparent materials at high NA a novel nonlinear Schr odinger equation is derived; the multiple rate equation (MRE) model is used to simultaneously calculate the generation of free electrons. Nonparaxial and vectorial effects are taken into account to accurately include tight focusing conditions. Parasitic effects are shown to get stronger and increasingly distortive for NA < 0.9, using water as a model substance for biological soft tissue and cellular constituents.

Rapid application of samples to thin-layer chromatographic plates

An inexpensive device for 16–21-s application of samples to thin-layer chromatographic plates is described. The reproducibility of application is comparable to that of standard methods and is adequate for quantification. Samples may be dissolved in a variety of solvents; those tested were chloroform, diisopropyl ether, ethyl acetate, butan-1-ol and plasma-water (1 + 1).