Calorimetric Studies on Chemically Delithiated LiNi0.4_{0.4}Mn0.4_{0.4}Co0.2_{0.2}O2_{2}: Investigation of Phase Transition, Gas Evolution and Enthalpy of Formation

Li1.11(Ni0.4Mn0.4Co0.2)O2 powders were chemically delithiated by (NH4)2S2O8 oxidizer to obtain Lix(Ni0.4Mn0.4Co0.2)O2 powders. The thermal behavior of two delithiated specimens, Li0.76Ni0.41Mn0.42Co0.17O2.10 and Li0.48Ni0.38Mn0.46Co0.16O2.07, was studied compared to the pristine specimen. Phase transitions at elevated temperatures were investigated by simultaneous thermal analysis (STA) and the gas evolution accompanying the phase transitions was analyzed by mass spectroscopy and an oxygen detector. The enthalpy of two delithiated samples and a pristine specimen were measured by a high temperature drop solution calorimeter. Based on these results, the enthalpies of formation were calculated

Laser-induced breakdown spectroscopy for the quantitative measurement of lithium concentration profiles in structured and unstructured electrodes

Quantitative chemical mapping of battery electrodes is a rather new post-mortem analytics method for identifying and describing chemical degradation processes in lithium-based battery systems. In consideration of future applications, the development of lithium-ion batteries is quite essential in order to meet requirements such as improved cell lifetime (>5000 cycles), high energy density at the cell level (>250 W h kg), reduced charging times (2500 W kg), and reduced manufacturing costs (<150 $ per kW h). One novel approach that can handle a contemporaneous enhancement of energy and power density is the development of a novel cell design, mandated in a threedimensional (3D) arrangement. This so-called “3D battery concept” enables electrode configurations with improved lithium-ion diffusion kinetics and provides reduced mechanical stresses which could arise during battery cycling. Within this study, laser-induced breakdown spectroscopy (LIBS) was applied quantitatively as a powerful analytical tool in order to study chemical degradation mechanisms and the impact of 3D electrode architectures on lithium distribution. It could be shown so far that free-standing electrode architectures can provide new lithium-insertion pathways which enhance the capability of the electrode material to operate under abuse conditions. Elemental mapping and elemental depth-profiling were applied for characterizing the electrode as a function of cell lifetime and architecture. For the first time, it was demonstrated that LIBS can be used to quantitatively describe lithium distribution in a 3D battery with specific design parameters. Finally, new scientific findings regarding electrochemically driven degradation and aging mechanisms of laser-structured, embossed, and unstructured NMC electrodes were explored

Impurities in commercial titanium dental implants – A mass and optical emission spectrometry elemental analysis

Objective: Titanium (Ti) is considered bioinert and is still regarded as the “gold standard” material for dental implants. However, even ‘commercial pure’ Ti will contain minor fractions of elemental impurities. Evidence demonstrating the release of Ti ions and particles from ‘passive’ implant surfaces is increasing and has been attributed to biocorrosion processes which may provoke immunological reactions. However, Ti observed in peri-implant tissues has been shown to be co-located with elements considered impurities in biomedical alloys. Accordingly, this study aimed to quantify the composition of impurities in commercial Ti dental implants. Methods: Fifteen commercial titanium dental implant systems were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES). Results: The elemental composition of implants manufactured from commercially pure grades of Ti, Ti-6Al-4V, and the TiZr alloy (Roxolid) conformed to the respective ISO/ASTM standards or manufacturers´ data (TiZr/Roxolid). However, all implants investigated included exogenous metal contaminants including Ni, Cr, Sb, and Nb to a variable extent. Other contaminants detected in a fraction of implants included As and the radionuclides U-238 and Th-232. Significance: Although all Ti implant studies conformed with their standard compositions, potentially allergenic, noxious metals and even radionuclides were detected. Since there are differences in the degree of contamination between the implant systems, a certain impurity fraction seems technically avoidable. The clinical relevance of these findings must be further investigated, and an adaptation of industry standards should be discussed

Systematic Study of the Multiple Variables Involved in V₂AlC Acid-Based Etching Processes, a Key Step in MXene Synthesis

The realization of the broad range of application of MXenes relies on the successful and reproducible synthesis of quality materials of tailored properties. To date, most MXenes have been produced making use of acid-based etching methods, yet an in-depth understanding of etching processes is lacking. Herein, we have engaged in a comprehensive study of the multiple variables involved in the synthesis of V2CTx with focus on the properties of etched materials. Two main sets of experiments were considered, each using a different V2AlC precursor and a range of synthesis variables including reaction time and temperature, mixing rate, and type of acid. Correlations of synthesis conditions–materials properties were investigated using a broad range of characterization techniques including analytical methods, scanning and transmission electron microscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Findings indicated the crucial relevance of properties of the MAX precursor such as elemental composition, particle size, and crystal structure on etching processes and properties of etched materials. Particularly, depending on the MAX precursor, two etching patterns were identified, core–shell and plate-by-plate, the latter describing a more efficient etching. Combined studies of elemental composition, crystal structure, and yield quantification allowed us to evaluate the effectiveness of etching processes. XRD studies revealed key crystal-structure-type of acid correlations showing advantages of using a HF/HCl mix over only HF. Analytical methods XRD and XPS delivered insights into undergoing chemical processes and their influence on bulk and surface chemistry of etched materials. The relevance for reaction kinetics of highly correlated variables such as reaction vessel dimensions, mixing efficiency, and reaction temperature was recognized. For the first time, a MXene synthesis has been investigated comprehensively highlighting its multivariable nature and the high variable intercorrelation, opening up venues for further investigation on MAX and MXene synthesis

Hopp om förbättring av överlevnad i ovarialcancer

Ovarian cancer is the most common cause of death from a gynecologic cancer. Every year around 700 women contracts ovarian cancer in Sweden. The overall survival is among the highest in Europe, but still long term relative survival is only 46%. It is a long-held myth that ovarian cancer is a disease without symptoms. Almost 90% of women have symptoms, even in the early stages. Symptoms that should arise suspicion of ovarian cancer and initiate diagnostic work-up are continuous abdominal extension, early feeling of satiety, pelvic or abdominal pain, urinary urge and postmenopausal bleeding. Women's awareness of symptoms and willingness to seek medical advice and the organization of the health care system are important factors determining cancer survival. Ovarian cancer is a heterogeneous group of diseases with different tumor traits and prognosis. Personalized medicine and preventive measures recognizing recent knowledge about tumor biology will positively affect survival