Development of a directly correlated Raman and uHPLC-MS content uniformity method for dry powder inhalers through statistical design,chemometrics and mathematical modeling

Context: Content uniformity (CU) is a critical quality attribute measured and monitored throughout the development and commercial supply of pharmaceutical products. Traditional high-performance liquid chromatography (HPLC) methods are time-consuming in both sample preparation and analysis. Thus, a rapid, nondestructive and preparation free spectroscopy based method such as Raman is preferred.

Objective: Multiple mathematical algorithms were used to establish robust and directly correlated Raman and ultra-HPLC-mass spectrometry (uHPLC-MS) CU methods for the rapid analysis of blends and agglomerates formulated for dry powder inhalers (DPIs).

Materials and Methods: Model samples included blends of caffeine and lactose; albuterol and lactose; and albuterol and lactose agglomerates. Design of experiments (DoE) was employed to optimize Raman spectra. Multivariate curve resolution (MCR) was leveraged to assess Raman method robustness. Mathematical modeling provided direct method to method correlation by allowing samples to be scanned first for Raman spectra and then dissolved for uHPLC-MS analysis. Several chemometric models were developed and evaluated for the quantitative analysis of CU.

Results: The DoE revealed Raman power and exposure time were negatively correlated when optimizing albuterol and caffeine spectra but positively correlated for lactose. MCR revealed regions in which small changes to power and time resulted in an 8–10% change in concentration predictions. A PCR model worked well for the analysis of caffeine blend samples and a PLS model worked best for both albuterol blends and agglomerates.

Discussion and Conclusion: Utilization of DoE, chemometrics and mathematical modeling provided a robust and directly correlated CU method for DPIs.     

Versatile Janus Architecture for Electrocatalytic Applications

Janus architectures have garnered great research efforts in recent years, leading to outstanding advances in electrocatalysis. Benefiting from the synergistic combination of their anisotropy which endows the manifestation of various co-existing electrochemical properties, and their compartmentalized structure that enables each functional domain to retain its inherent activity, with little to no interference from other domains, Janus architectures show great potential as exceptionally versatile electrocatalysts to complement a plethora of electrocatalytic processes. Thus, coupled with the growing interest in Janus architectures for electrocatalysis, it is imperative to investigate and reconsider their design strategies and future directions.     

Hexavalent chromium removal by reduction with ferrous sulfate, coagulation, and filtration: a pilot-scale study

A flow-through pilot-scale system was tested for removal of Cr(VI) from contaminated groundwater in Glendale, California. The process consisted of the reduction of Cr(VI) to Cr(lll) using ferrous sulfate followed by coagulation and filtration. Results indicated that the technology could reduce influent Cr(VI) concentrations of 100 microg L(-1) to below detectable levels and also remove total Cr (Cr(VI) plus Cr(lll)) to very low concentrations (< 5 microg L(-1)) under optimized conditions. Complete reduction of Cr(VI) to Cr(lll) was accomplished with Fe(ll) doses of 10-50 times the Cr(Vl) concentration even in the presence of significant dissolved oxygen levels. The overall Cr removal efficiency was largely determined by the filterability of Cr(lll) and Fe(lll) precipitates, of which a relatively high filtration pH (7.5-7.6) and high filter loading rate (6 gpm ft(-2)) had negative impacts. The pilot system was able to operate for an extended time period (23-46 h depending on the Fe:Cr mass ratio) before turbidity breakthrough or high head loss. Backwash water was effectively settled with low doses (0.2-1.0 mg L(-1)) of high molecular weight polymer. Backwash solids were found to be nonhazardous bythe toxicity characteristic leaching procedure but hazardous by the California waste extraction test.     

Porewater evidence of metal (Cu, Ni, Co, Zn, Cd) mobilization in an acidic, ombrotrophic bog impacted by a smelter, Harjavalta, Finland and comparison with reference sites

Porewaters were collected from three Finnish peat bogs subjected to varying inputs of atmospheric trace metals: Hietaj?rvi (HIJ), a low-background site, Outokumpu (OUT), near a Cu-Ni mine, and Harjavalta (HAR), near a Cu-Ni smelter. Samples for metal analyses were collected at depths ranging from 10 to 70 cm using a purpose-built syringe-type sampler. Metal concentrations were determined using inductively coupled plasma-sector field-mass spectrometry (ICP-SF-MS). Porewater concentrations at HIJ and OUT (Cd <0.3 nM, Co <1.4 nM, Cu, Ni <8 nM, Zn <250 nM) are independent of metal concentrations in the solid phase (peat). At OUT there is a limited release of Ni to the porewaters, but concentrations in the aqueous phase are generally below 0.3% of the total concentration in any given peat sample. These data are consistent with the immobility of these metals after deposition from the air. In contrast, porewaters at HAR are enriched in trace metals compared to the other sites by a factor of 2 (Zn), 10 (Cd), 20 (Co), and 100 (Cu and Ni) with dissolved fractions of Cu and Ni accounting for ca. 20% of the metal inventories in the cores. The elevated release of metals from solid phases at HAR is consistent with the postdepositional migration of metals at this site and reflects the predominance of oxide phases supplied to the bog surface and the much lower pH values (<3.4). The elevated proton concentrations not only promote mineral dissolution but also compete with cation exchange processes and hinder the formation of metal complexes with organic ligands.     

Interface adjustment between poly(ethylene terephthalate) and graphene oxide in order to enhance mechanical and thermal properties of nanocomposites

There is great interest in the use of graphene and derivatives in the production of polymer nanocomposites as it provides improvements in the properties of the materials to which they are associated. Such improvements depend heavily on filler dispersion and the interaction between the nanomaterials and the matrix. This work aimed to study the compatibility of graphene oxide (GO) with a poly(ethylene terephthalate) matrix. For this, graphite was modified using Hummers method, using reaction times of 3 and 6 h. The obtained GO was functionalized with amine, amide, and magnetite groups (FGO). The effects of the oxidation degree, functionalization and concentration of the nanofillers on the dispersion and consequently on the properties of the polymer nanocomposites were evaluated. The nanocomposites were synthesized by the solid–solid deposition method followed by the melt mixing technique. It was observed that lower concentrations of nanofiller associated with the lower degree of oxidation and functionalization improved the interaction of the nanofillers with the matrix, which resulted in better mechanical properties under tensile stresses for strain at break, maximum stress, Young's modulus and toughness. It was also observed that the glass transition and crystallization of nanocomposites increased due to a nucleating effect of the nanofillers.     

O-GlcNAcylation Affects the Pathway Choice of DNA Double-Strand Break Repair

Exposing cells to DNA damaging agents, such as ionizing radiation (IR) or cytotoxic chemicals, can cause DNA double-strand breaks (DSBs), which are crucial to repair to maintain genetic integrity. O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) is a post-translational modification (PTM), which has been reported to be involved in the DNA damage response (DDR) and chromatin remodeling. Here, we investigated the impact of O-GlcNAcylation on the DDR, DSB repair and chromatin status in more detail. We also applied charged particle irradiation to analyze differences of O-GlcNAcylation and its impact on DSB repair in respect of spatial dose deposition and radiation quality. Various techniques were used, such as the γH2AX foci assay, live cell microscopy and Fluorescence Lifetime Microscopy (FLIM) to detect DSB rejoining, protein accumulation and chromatin states after treating the cells with O-GlcNAc transferase (OGT) or O-GlcNAcase (OGA) inhibitors. We confirmed that O-GlcNAcylation of MDC1 is increased upon irradiation and identified additional repair factors related to Homologous Recombination (HR), CtIP and BRCA1, which were increasingly O-GlcNAcyated upon irradiation. This is consistent with our findings that the function of HR is affected by OGT inhibition. Besides, we found that OGT and OGA activity modulate chromatin compaction states, providing a potential additional level of DNA-repair regulation.     

Blown film extrusion of poly(lactic acid) without melt strength enhancers

Processing strategies were developed to manufacture poly(lactic acid) (PLA) blown films without melt strength enhancers (MSEs). The effects of processing temperature on PLA's melt properties (shear and elongational viscosities), PLA grades, and other processing conditions [ratio of take‐up roller to extruder's rotational screw speeds or processing speed ratio (PSR) and internal air pressures] on film's blow‐up ratio were examined. Experimental results indicate that extrusion‐blown amorphous and semicrystalline PLA films can be successfully manufactured without MSEs by controlling melt rheology through processing temperature and other extrusion processing conditions. PLA processed at lower extrusion temperature had higher melt viscosities, which favored the formation of stable films depending on the PSR and internal air pressure used. Inappropriate control of PSR and internal air pressure led to unstable films with various processing defects such as melt sag, bubble dancing, or draw resonance, irrespective of the lower extrusion processing temperature. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45212.     

Evaluation of the implementation fidelity of an ergonomic training program designed to prevent back pain

The aim of this study was to evaluate the implementation fidelity of a multidimensional ergonomic program designed to prevent back pain injuries among healthcare personnel. The program, provided by peer trainers included training intended to modify patient handling and transfer behaviour, trainee follow-up, prevention activities aimed at work environment improvements and follow-up monitors training. Two hundred twenty-one peer trainers at 139 Quebec healthcare institutions participated in our study. Only 61.5% were involved in training; most of them taught safe patient handling, positioning, transfer, and preparation techniques, which are the cornerstones of the program; 72.7% were involved in prevention activities, 46.1% in follow-up activities, and 10.7% in follow-up monitors training. The study results should help organizations anticipate and prevent potential discrepancies between prescribed and implemented programs.     

Efficient computation of maximal orders in radical (including Kummer) extensions

We describe an algorithm, linear in the degree of the field, for computing a (pseudo) basis for P$P$-maximal orders of radical (which includes Kummer) extensions of global arithmetic fields. We construct our basis in such a way as to further improve maximal order computations in these radical extensions. Using this algorithm for the similar problem of computing maximal orders of class fields is discussed. We give examples of both function fields and number fields comparing the running time of our algorithm to that of the Round 2 or 4 and Fraatz (2005).