Direct Ionic Liquid Extractant Injection for Volatile Chemical Analysis - A Gas Chromatography Sampling Technique

A green sampling approach by direct injection of ionic liquid (IL) solvent containing a variety of analytes using programmable temperature vaporisation (PTV) injection with gas chromatography (GC) is presented. The method was developed using test mixtures of n-alkanes, n-alcohols and polyaromatic compounds, whilst back extraction of isolated compounds from the IL with organic solvent is not required. In the final method, 2 μL of IL, 1-butyl-3 methylimidazolium bis(trifluoromethylsulfonyl)amide containing analytes, was diluted to different volumes (ranging from 10 to 70%) with solvent then injected into the system. Several PTV injector parameters were investigated to ensure analyte volatilisation and transfer into the GC column. Concentration calibration curves (10–150 μg mL−1 and 10–100 μg mL−1 for n-alkanes and n-alcohols, respectively) were constructed, and showed addition of IL increased the peak area of each analyte, with good precision, and acceptable linearity with correlation coefficient, r2 > 0.93. This method was successfully applied in analysis of a polynuclear aromatic hydrocarbons (PAHs) mixture, with addition of IL in the mixture and suitable operation of the PTV injector. The method was also applied to eucalyptus leaf essential oil compounds as a test sample in a single drop microextraction experiment

Alcohol and marijuana use while driving-an unexpected crash risk in Pakistani commercial drivers: a cross-sectional survey

Background:A significant proportion of road traffic crashes are attributable to alcohol and marijuana use while driving globally. Sale and use of both substances is illegal in Pakistan and is not considered a threat for road traffic injuries. However literature hints that this may not be the case. We did this study to assess usage of alcohol and marijuana in Pakistani commercial drivers.Methods:A sample of 857 commercial bus and truck drivers was interviewed in October 2008 at the largest commercial vehicle station in Rawalpindi and Islamabad, Pakistan. Time location cluster sampling was used to select the subjects and a structured questionnaire was used to assess the basic demographic profile, substance abuse habits of the drivers while on the road, and reasons for usage of illicit substances while driving were recorded. Self reported information was collected after obtaining informed consent. Chi square and fisher exact tests were used to assess differences between groups and logistic regression was used to identify significant associations between driver characteristics and alcohol and marijuana use.Results:Almost 10% of truck drivers use alcohol while driving on Pakistani roads. Marijuana use is almost 30% in some groups. Statistically different patterns of usage are seen between population subgroups based on age, ethnicity, education, and marital status. Regression analysis shows association of alcohol and marijuana use with road rage and error behaviours, and also with an increased risk of being involved in road crashes. The reported reasons for using alcohol or marijuana show a general lack of awareness of the hazardous nature of this practice among the commercial driver population.Conclusion:Alcohol and marijuana use is highly prevalent in Pakistani commercial drivers. The issue needs to be recognized by concerned authorities and methods such as random breath tests and sobriety check points need to be employed for proper law enforcement

Influence of Temperature Fields on the Processing of Polymer Powders by Means of Laser and Mask Sintering Technology

Besides their high potential for individual series-production, powder and beam based additive manufacturing technologies, like laser and mask sintering, are in general still restricted to prototyping applications. This is a result of multiple limitations concerning part properties (e.g. mechanical and geometrical), their insufficient reproducibility due to transient thermal conditions and the limited range of available materials. The main focal point of this paper is to show the influencing parameters (e.g. temperature fields in the building chamber) of powder-based thermoplastic processing technologies on part properties, like porosity and surface quality, and on the processability of further new polymers (e.g. polypropylene and polyoxymethylene).Mechanical Engineerin

Identification of Equid herpesvirus 2 in tissue-engineered equine tendon

Background: Incidental findings of virus-like particles were identified following electron microscopy of tissue-engineered tendon constructs (TETC) derived from equine tenocytes. We set out to determine the nature of these particles, as there are few studies which identify virus in tendons per se, and their presence could have implications for tissue-engineering using allogenic grafts. Methods: Virus particles were identified in electron microscopy of TETCs. Virion morphology was used to initially hypothesise the virus identity.  Next generation sequencing was implemented to identify the virus. A pan herpesvirus PCR was used to validate the RNASeq findings using an independent platform. Histological analysis and biochemical analysis was undertaken on the TETCs. Results: Morphological features suggested the virus to be either a retrovirus or herpesvirus. Subsequent next generation sequencing mapped reads to Equid herpesvirus 2 (EHV2). Histological examination and biochemical testing for collagen content revealed no significant differences between virally affected TETCs and non-affected TETCs. An independent set of equine superficial digital flexor tendon tissue (n=10) examined using designed primers for specific EHV2 contigs identified at sequencing were negative. These data suggest that EHV is resident in some equine tendon. Conclusions: EHV2 was demonstrated in equine tenocytes for the first time; likely from in vivo infection. The presence of EHV2 could have implications to both tissue-engineering and tendinopathy

The inaugural australian centre for hepatitis virology public panel discussion on viral hepatitis research—lessons in scientific community outreach

Viral hepatitis remains one of the most significant health issues globally, directly responsible for over 1 million deaths each year and affecting almost 300 million people around the world. Scientific research in recent decades has brought about improvements in the lives of people living with chronic viral hepatitis. On the 29 July 2021, the Australian Centre for Hepatitis Virology (ACHV) for the first time held a public educational forum for the general public. The main aim of this event was to inform the affected community about the importance of scientific research and give an overview of upcoming developments in the field. Here, we provide a detailed report of the panel discussion (including its organisation, execution, and lessons learned to incorporate into future events) and provide strategies that can be used by other scientific societies to hold similar events in their own communities

Enhancing the Thermal Stability of Polyamide 6 in Powder Bed Fusion via Primary and Secondary Antioxidant Incorporation

Polyamide 6 (PA6) is a thermoplastic material widely used in manufacturing for its excellent mechanical properties, such as high strength, stiffness, and toughness. However, its suitability for powder bed fusion (PBF) is limited due to its susceptibility to thermo-oxidative aging, resulting in material degradation and mechanical property deterioration over time. To address this issue, the efficacy of antioxidants in increasing the aging resistance of PA6 in PBF was investigated. Process-adapted analysis was employed using a coupled rheometer FTIR instrument to elucidate physical and chemical changes in the material. In addition, the viscosity number of the virgin and processed powder, the yellow index, and the part performance were evaluated. Results revealed that the addition of primary and secondary antioxidants significantly enhanced the aging resistance of PA6 in PBF, thereby increasing its potential as a suitable material for additive manufacturing applications.Mechanical Engineerin

Analysis of Flow Additives in Laser-Based Powder Bed Fusion of Polymers: Implications for Flow Behavior, Processing, Temperature Profile, and Part Characteristics

Powder bed fusion of polymers requires the use of flow additives to ensure adequate flowability of the feedstock material. However, information regarding flow additives and their load is limited, as is an understanding of their impact on processing conditions. This study investigates the flow behavior using static and dynamic measurements under process conditions, focusing on the influence of flow additives. Subsequently, processing studies are conducted using thermography to analyze the laser-material interaction. The characteristics of parts produced from Polypropylene and Polyamide 12 systems are also examined. The findings of this research enhance the understanding of the impact of flow additives on the processing conditions of laser-based powder bed fusion of polymers, potentially leading to optimized process parameters and improved part quality and mechanical properties.Mechanical Engineerin

Vibrational Microfeeding of Polymer and Metal Powders for Locally Graded Properties in Powder-Based Additive Manufacturing

Subject of this work is the contact mechanical properties and flowability of polymer and metal powders when they are dispensed on the surface of a powder bed for use in laser-based powder bed fusion in additive manufacturing. Generating local part properties in metal as well as polymer-based powder bed fusion processes is of high interest, so an approach is made to locally add additives by a vibrational microfeeding system for metal and polymer powders. To realize a controlled powder discharge, the behavior of additives, which are dropped on a surface and on a powder bed is analyzed. Influencing factors for mass flow of the powders will be excitation frequency, excitation amplitude and capillary diameter on the side of experimental setup as well as particle size distribution and physical properties on the material side

Process‐Dependent Variations in the Proliferation of Myoblasts, Fibroblasts and Chondrocytes on Laser‐Sintered Polypropylene

ABSTRACT Additively manufactured polyolefins find broad applications in medical engineering, enabling the manufacturing of patient‐specific geometries. For investigating the influence of processing conditions of laser sintered locally macroporous polypropylene substrates, the response of myoblasts, chondrocytes, and fibroblasts has been characterized in this study. An influence of the applied manufacturing parameters on the attachment and viability of the investigated cells is observed, showing the effect of the superficial pore topology on the attachment and the spreading of cells. The viability and attachment of fibroblasts and chondrocytes could be improved by reducing the thermal exposure during the processing step of the dense base part, associated with increased superficial porosity and the corresponding increase of the surface area. The applied additive manufacturing process of macroporous structures influences emerging cell morphologies, leading to an extended morphological expression of chondrocytes and the overgrowth of small pores by fibroblasts. This indicates an improvement in superficial cell adhesion due to larger pores. These findings indicate the significance of the processing conditions in laser sintering of polypropylene on the cell response through the optimization of processing parameters and the attachment of an open‐cell pore structure.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) http://dx.doi.org/10.13039/50110000165

Določanje benzodiazepinov v urinu preko benzofenonskih derivatov z uporabo tekočinske kromatografije sklopljene s tandemsko masno spektrometrijo

The aim of this study was to validate a new method for determining benzodiazepines in urine via their benzophenone derivatives, based on liquid chromatography-tandem mass spectrometry (LC-MS/MS). Selected benzodiazepines were analysed after acid hydrolysis of urine and extraction by ethyl acetate in the presence of an internal standard. Samples were analysed using electrospray ionization LC-MS/MS in a multiple reaction monitoring mode. The chromatographic run time on a reversed phase C18 analytical column was set for 9 min. This method was validated in 21 patients receiving methadone. Benzodiazepines intake was established in two out of three patients. LC-MS/MS results were also compared with the rapid immunoassay and the methods showed good agreement. However, in three cases benzodiazepines were detected by LC-MS/MS, but not by the immunoassay. The sensitivity of the developed LC-MS/MS method is comparable to or even higher than of previously reported methods, which makes it suitable as a confi rmatory method.Razvili smo selektivno in občutljivo metodo za določanje nekaterih benzodiazepinov v urinu preko določanja njihovih benzofenonov. Metoda temelji na tekočinski kromatografi ji, sklopljeni s tandemsko masno spektrometrijo (LC-MS/MS). Izbrane benzodiazepine smo analizirali po kisli hidrolizi urinskih vzorcev in ekstrakciji z etilacetatom v prisotnosti internega standarda. Vzorce smo analizirali z elektrorazprševalno ionizacijo z MRM načinom detekcije. Čas kromatografske ločbe na reverznofazni (C18) analitski koloni je bil 9 min. Metoda je bila validirana in preizkušena na 21 pacientih, ki so prejemali metadonsko terapijo. Pri dveh tretjinah primerov je bil vnos benzodiazepinov tudi potrjen. Vzorce smo testirali tudi s hitro imunokemijsko metodo in rezultate primerjali z rezultati pridobljenimi z LC-MS/MS metodo. Ugotovili smo dobro ujemanje med rezultati pridobljenimi z obe a metodama. Kljub temu smo v treh primerih določili prisotnost benzodiazepinov z LC-MS/MS metodo, ki je z imunokemijsko metodo nismo. Občutljivost razvite metode je primerljiva ali celo boljša od predhodno opisanih metod, zato jo lahko uporabimo kot potrditveno metodo