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In this processing study we systematically investigate the impact of lithium excess and dwell time on Ga-substituted LLZO:Ga and show that Li-excess during synthesis and processing is a critical parameter to obtain peak performance.

Garnet-based Li7La3Zr2O12 (LLZO) is considered one of the most promising oxide-ceramic solid electrolyte materials for inorganic all-solid-state batteries. Dopants and substituents like Al, Ta, Nb, Ga, and W were shown to have a high impact on the total ionic conductivity, increasing it from 10−6 S/cm up to 10−3 S/cm. However, natural zirconium sources always contain a small amount of hafnium which could also act as dopant, but the separation of these two elements is complicated and expensive. In this work, we investigate the influence of various Hf-impurity concentrations on the performance of tantalum-doped LLZO. We synthesised Li6.45Al0.05La3Zr1.6−xHfxTa0.4O12 (LLZHO with x = 0 – 1.6) via conventional solid-state synthesis and have demonstrated that up to x = 0.1, hafnium impurities do not have a significant impact on the performance of the material. Above this concentration, the Li-ion conductivity is steadily reduced to around 70% when zirconium is fully substituted by hafnium resulting in Li6.45Al0.05La3Hf1.6Ta0.4O12. As the purity of Zr precursors has a great impact on their price, these findings can help to reduce the price of LLZO in general, as lower grade zirconium can be used in industrial scale applications.

Journal of materials chemistry / A 9(8), 4831-4840 (2021). doi:10.1039/D0TA11096E, Published by Royal Soceity of Chemistry, London [u.a.]

Garnet-based all-solid-state batteries (ASBs) with high energy density require composite cathodes with high areal loading and high-capacity cathode active materials. While all ceramic cathodes can typically be manufactured via cosintering, the elevated temperatures necessary for this process pose challenges with respect to material compatibility. High-capacity cathode active materials like Ni-rich LiNixCoyMn1–x–yO2 (NCM) show insufficient material compatibility toward the solid electrolyte Li6.45Al0.05La3Zr1.6Ta0.4O12 (LLZO:Ta) during cosintering, leading to the formation of highly resistive interphases. We investigated this secondary phase formation both experimentally and via density functional theory calculation to get a mechanistic understanding of the cosintering behavior of LLZO:Ta with NCM111 and Ni-rich NCM811. Furthermore, we employed B doping of both NCM materials in order to assess its impact on the cation interchange and subsequent secondary phase formation. While secondary phases were formed for all four NCM materials, their onset temperature, nature, and amount strongly depend on the NCM composition and doping. Surprisingly, Ni-rich NCM811 turned out to be the most promising cathode active material for the combination with garnet-type LLZO:Ta. As proof of concept, fully inorganic, ceramic all-solid-state lithium batteries featuring only a Li-metal anode, an LLZO:Ta separator, and a composite cathode, consisting of LLZO:Ta, Li3BO3, and NCM811, were prepared by conventional sintering. The purely inorganic full cells delivered a high specific areal discharge capacity of 0.7 mA h cm–2 in the initial cycle.

Solid electrolyte is the key component in all-solid-state batteries (ASBs). It is required in electrodes to enhance Li-conductivity and can be directly used as a separator. With its high Li-conductivity and chemical stability towards metallic lithium, lithium-stuffed garnet material Li7La3Zr2O12 (LLZO) is considered one of the most promising solid electrolyte materials for high-energy ceramic ASBs. However, in order to obtain high conductivities, rare-earth elements such as tantalum or niobium are used to stabilize the highly conductive cubic phase. This stabilization can also be obtained via high levels of aluminum, reducing the cost of LLZO but also reducing processability and the Li-conductivity. To find the sweet spot for a potential market introduction of garnet-based solid-state batteries, scalable and industrially usable syntheses of LLZO with high processability and good conductivity are indispensable. In this study, four different synthesis methods (solid-state reaction (SSR), solution-assisted solid-state reaction (SASSR), co-precipitation (CP), and spray-drying (SD)) were used and compared for the synthesis of aluminum-substituted LLZO (Al:LLZO, Li6.4Al0.2La3Zr2O12), focusing on electrochemical performance on the one hand and scalability and environmental footprint on the other hand. The synthesis was successful via all four methods, resulting in a Li-ion conductivity of 2.0–3.3 × 10−4 S/cm. By using wet-chemical synthesis methods, the calcination time could be reduced from two calcination steps for 20 h at 850 °C and 1000 °C to only 1 h at 1000 °C for the spray-drying method. We were able to scale the synthesis up to a kg-scale and show the potential of the different synthesis methods for mass production.

Crystals of M(NH3)2[N(CN)2]2 with M = Ni and Co were obtained from the reaction of stoichiometric amounts of Na[N(CN)2] with NiCl2·6H2O or CoCl2·6H2O in aqueous, ammoniacal solutions. X-ray single-crystal structure analyses show that M(NH3)2[N(CN)2]2 with M = Ni and Co crystallize isotypically to each other and adopt the monoclinic space group P21/ c (no. 14). The lattice parameters of Ni(NH3)2[N(CN)2]2 are a = 5.8498(9) A, b = 10.6739(12) A, and c = 6.8089(17) A, β = 98.037(3)° and Z = 2, while those of Co(NH3)2[N(CN)2]2 are a = 5.8303(11) A, b = 10.746(2) A, c = 6.7773(13) A, and β = 96.422(3)°. In addition, the crystal structure of the nickel compound was refined from neutron powder diffraction, augmented by DFT calculations as regards atomic displacement parameters. The IR spectra of the title compounds exhibit modes typical for the dicyanamide anion and ammonia. The UV/vis spectrum of Ni(NH3)2[N(CN)2]2 shows that the dicyanamide moiety is a medium-field ligand. Additional superconducting quantum interference device (SQUID) magnetic susceptibility measurements of Ni(NH3)2[N(CN)2]2 and Co(NH3)2[N(CN)2]2 confirm not only significant high-spin moments of χm T = 1.24 cm3·K·mol-1 (μeff = 3.15 μB) and 2.89 cm3·K·mol-1 (μeff = 4.81 μB), respectively, at 290 K and 0.1 T but also an absence of magnetic ordering.

In our work we demonstrate a facile, water-free synthesis of amorphous lithium niobate (LiNbO3) layers. Our developed method also enables the coating of substrates in inert atmosphere with simple, industrial scalable methods. As verification, a 120 nm thin LiNbO3 layer was deposited on the garnet type lithium ion conductor Li6.45Al0.05La3Zr1.6Ta0.4O12 (LLZTO) to improve its interface to lithium metal and reduce dendrite formation. The application of the thin film reduced the interface resistance between LLZTO and lithium metal to 1.02(13) Ω∙cm2 and was able to suppress dendrite formation for current densities of up to 0.5 mA/cm2. The chemical stability of the LiNbO3 thin film in contact with Li-metal was verified by SEM, XPS and ToF-SIMS.

PbNCN, Ag2NCN, and ZnNCN were tested as negative\ud electrode materials for Li-ion batteries. A thorough analysis of the\ud electrochemical mechanism by X-ray diffraction and X-ray absorption\ud spectroscopy showed that, unlike transition metal carbodiimides, these\ud compounds react with lithium via a two-step reaction, starting with\ud conversion followed by alloying. The conversion reaction is highly\ud irreversible for the three compounds, whereas the reversibility of the alloying\ud reaction depends on the metal, that is, highly irreversible for PbNCN and\ud Ag2NCN which contain the cyanamide group (NC−N2−) and more\ud reversible for ZnNCN containing carbodiimide (−NCN−). In the case\ud of the more covalent, cyanamide-type PbNCN and Ag2NCN, the conversion\ud reaction occurs at a higher voltage compared to the more ionic,\ud carbodiimide-type ZnNCN, correlated with the nature of bonding in the\ud NCN group and in the phases themselves. Compared to transition metal carbodiimides, these materials show rather low\ud performance, with no improvement in capacity as it would have been expected from the combination of conversion and\ud alloying.

CuWO4 is a photoanode candidate in neutral pH, and manganese-based oxygen evolution reaction electrocatalysts are of high interest due to their low price and low toxicity. Considering the unexplored chemistry of transition-metal carbodiimides/cyanamides for the PEC water oxidation, we investigated MnNCN as an electrocatalyst for CuWO4 under AM 1.5G illumination in potassium phosphate electrolyte (pH 7). Surface functionalization of CuWO4 photoanodes with MnNCN increased the photocurrent from 22 to 30 μA cm-2 at 1.23 V vs RHE. Complementary structural analysis by means of XRD and XPS revealed that MnNCN forms a core-shell structure MnNCN@MnPO x in phosphate electrolyte and mimics a manganese phosphate electrocatalyst. As such, the surface chemistry of MnNCN significantly differs from previous studies on the cobalt analogue (CoNCN). A separately prepared MnNCN electrode developed a small but detectable photocurrent due to photogenerated holes inside the semiconducting carbodiimide core of the MnNCN@MnPO x structure.

We investigated CuWO4 as a promising photoanode and its surface functionalization with Ag2NCN. The composite photoanode displays a synergetic effect between its constituents during photoelectrochemical (PEC) water oxidation. After placing Ag2NCN particles on the CuWO4 thin film, the photocurrent density increases from 15 to 45 μA cm–2 at 1.23 V vs reversible hydrogen electrode (RHE) in phosphate buffer electrolyte at pH 7 under simulated AM1.5 G illumination. The different positions of the band edges of CuWO4 and Ag2NCN favor charge carrier separation at their interface. Upon illumination, photogenerated electrons of both semiconductors are transferred to the conduction band and can migrate to the counterelectrode. The higher position of the conduction band edge of Ag2NCN allows its electrons to be injected into the conduction band of CuWO4. Simultaneously, holes from the cyanamide are blocked, because the valence band edge position of CuWO4 is positioned lower than for Ag2NCN. This results in more effici...

A matched-pair comparison between the modified Merendino resection (MER) and Ivor Lewis resection (ILR) for early Barrett’s carcinoma. Early adenocarcinoma of the esophagus (eACE) with positive risk factors for lymph node metastasis (LNM) needs surgery for cure. MER appeared to be an alternative to ILR. Between July 2000 and July 2012, 156 patients with high-grade dysplasia or eACE received ILR, whereas in 30 cases MER was performed in a tertiary care center for GI Surgery. A matched-pair analysis was performed on the basis of sex, age, BMI, ASA classification and tumor stage. Thirty patients were assigned to each group. The data were analyzed regarding perioperative aspects (e.g., operating time, hospital stay, complications, number of lymph nodes) and survival analysis. The mean operating time was 301.7 min for ILR, compared to 255.4 min for MER (p = 0.044). The hospital stay following ILR was significantly longer than for MER (22.4 days ILR vs. 16.4 days MER, p = 0.023). There was no statistically significant difference regarding complications between the two groups (p = 0.463). The number of resected lymph nodes was significantly lower in the MER group (median 21) compared to the ILR group, where a median of 31 lymph nodes could be removed (p

Research in early esophageal adenocarcinoma focused on prediction of lymph node metastases in order to stratify patients for endoscopic treatment instead of esophagectomy. Although distant metastases were described in rates of up to 13% of patients within a follow-up of 3 years, their prediction has been neglected so far. In a secondary analysis, a cohort of 217 patients (53 T1a and 164 T1b) treated by esophagectomy was analyzed for histopathological risk factors. Their ability to predict the combination of lymph node metastases at surgery as well as metachronous locoregional and distant metastases (overall metastatic rate) was assessed by uni- and multivariate logistic regression analysis. Tumor invasion depth was correlated with both lymph node metastases at surgery (τ = 0.141; P = .012), tumor recurrences (τ = 0.152; P = .014), and distant metastases (τ = 0.122; P = 0.04). Multivariate analysis showed an odds ratio of 1.31 (95% CI 1.02–1.67; P = .033) per increasing tumor invasion depth and of 3.5 (95% CI 1.70–6.56; P

International audience; Cobalt carbodiimide, CoNCN, shows outstanding performance as negative electrode material for Li‐ion batteries, maintaining a reversible capacity of 530 mAh g−1 over 140 cycles at a current density of 540 mA g−1. The electrochemical lithiation/delithiation mechanism of cobalt carbodiimide was investigated using complementary in situ X‐ray diffraction and X‐ray absorption spectroscopy. Upon lithiation, CoNCN undergoes a reversible conversion reaction, forming Li2NCN and fcc Co metal nanoparticles, which are transformed back into CoNCN upon delithiation. However, the CoNCN obtained electrochemically after delithiation do not recover the local structure of the pristine phase, and might contain the NCN2− ligand in the cyanamide isomer form (N−C≡N2−). It would be the first time that a transition metal cyanamide isomer is obtained at ambient conditions.

Crystals of M(NH

This paper reports on experimental investigations of turbulent flame-wall interaction (FWI) during transient head-on quenching (HOQ) of premixed flames. The entire process, including flame-wall approach and flame quenching, was analyzed using high repetition rate particle image velocimetry (PIV) and simultaneous flame front tracking based on laser-induced fluorescence (LIF) of the OH molecule. The influence of convection upon flame structures and flow fields was analyzed qualitatively and quantitatively for the fuels methane (CH4) and ethylene (C2H4) at ϕ = 1. For this transient FWI, flames were initialized by laser spark ignition 5 mm above the burner nozzle. Subsequently, flames propagated against a steel wall, located 32 mm above the burner nozzle, where they were eventually quenched in the HOQ regime due to enthalpy losses. Twenty ignition events were recorded and analyzed for each fuel. Quenching distances were 179 μm for CH4 and 159 μm for C2H4, which lead by nondimensionalization with flame thickness to Peclet numbers of 3.1 and 5.5, respectively. Flame wrinkling and fresh gas velocity fluctuations proved flame and flow laminarization during wall approach. Velocity fluctuations cause flame wrinkling, which is higher for CH4 than C2H4 despite lower velocity fluctuations. Lewis number effects explained this phenomenon. Results from flame propagation showed that convection dominates propagation far from the wall and differences in flame propagation are related to the different laminar flame speeds of the fuels. Close to the wall flames of both fuels propagate similarly, but experimental results clearly indicate a decrease in intrinsic flame speed. In general, the experimental results are in good agreement with other experimental studies and several numerical studies, which are mainly based on direct numerical simulations.

SUMMARYThe overall metastatic potential of surgically treated early esophageal adenocarcinoma has not been studied in detail. This paper therefore assessed lymph node metastases at surgery, loco regional and distant metastases, in order to assess the metastatic potential of early esophageal adenocarcinoma. Two hundred and seventeen patients (53 T1a, 164 T1b; median follow-ups 87 and 75 months, 187 males) diagnosed with early esophageal adenocarcinoma and treated with esophagectomy in our tertiary center's database between July 2000 and December 2015 were included. All metastatic events were retrospectively analyzed, their topographic distribution was assessed, and the overall metastatic rate was calculated. Lymph node metastases occurred in 39 patients (18%) and 29 (13.4%) developed recurrences. Lymph node metastases were absent in m1 and m2 tumors and rare in m3 (1/18), m4 (5/21), and sm1 (4/42), but more frequent in sm2 (11/44) and sm3 tumors (18/78). Locoregional recurrences were exceedingly rare in m3 (2/18), m4 (1/21), sm1 (1/42), and sm2 (2/44), but frequent in sm3 (12/78). In contrast, distant metastases were more frequent with 2/18 in m3, 1/21 in m4, 4/42 in sm1, 4/44 in sm2, and 13/78 in sm3. Overall metastatic rates of 11.9% in sm1 (submucosal layer divided into equal thirds), 27.3% in sm2, and 32.1% in sm3 tumors were calculated. This first report of the metastatic potential of early esophageal adenocarcinoma provides a meticulous assessment of the overall metastatic risk. Metastatic events pose a relevant risk in surgically treated patients with esophageal adenocarcinoma with distant metastases being more frequent than locoregional recurrences.

CuWO

International audience; A little less than a decade after their quantum-chemical prediction and eventual synthesis, solid-state transition-metal carbodiimides and closely related compounds have somewhat unexpectedly emerged as energy materials. In these carbodiimides, the O2− oxide dianion has been replaced by the complex NCN2− dianion, and the outstanding properties of such materials are likely related to their metastability and their higher amount of covalency compared to related oxides. When used as anode materials in rechargeable Li- and Na-ion batteries, one finds a conversion reaction, and further improving their performance will likely involve studying the redox behavior of NCN2−, the synthesis of novel ternary carbodiimides, in particular those with redox-active transition metals, and controlling their morphology. At present, such materials serve as catalysts in photochemical water oxidation, where they outperform their oxide cousins.

Hybrid femtosecond/picosecond rotational coherent anti-Stokes Raman spectroscopy (CARS) is developed utilizing a two-beam phase-matching approach for one-dimensional (1D) measurements demonstrated in an impinging jet burner to probe time-resolved head on quenching (HOQ) of a methane/air premixed flame at Φ = 1.0 and Reynolds number = 5000. Single-laser-shot 1D temperature profiles are obtained over a distance of at least 4 mm by fitting the pure-rotational N 2 CARS spectra to a spectral library calculated from a time-domain CARS code. An imaging resolution of ∼61 μm is obtained in the 1D-CARS measurements. The acquisition of single-shot 1D CARS measurements, as opposed to traditional point-wise CARS techniques, enables new spatially correlated conditional statistics to be determined, such as the position, magnitude, and fluctuations of the instantaneous temperature gradient. The temperature gradient increases as the flame approaches the metal surface, and decreases during quenching. The standard deviation of the temperature gradient follows the same trend as the temperature gradient, increasing as the flame front approaches the surface, and decreasing after quenching.

Energy technology 8(3), 1901260 (2020). doi:10.1002/ente.201901260, Published by Wiley-VCH, Weinheim [u.a.]

This paper reports on simultaneous measurement of temperature and CO concentration in atmospheric methane/air jet flames impinging vertically against a water-cooled stainless-steel wall. Flame–wall interactions are investigated for statistically stationary flames and propagating flames, representing the recognized case of head-on quenching. Instantaneous temperatures are determined using nanosecond coherent anti-Stokes Raman spectroscopy of nitrogen (CARS); CO concentrations are measured using two-photon laser-induced fluorescence (LIF). Statistically stationary flames are investigated in a parametric study for equivalence ratios (0.83 ϕ ϕ 2 . The normalized quenching heat flux is found to be 0.29 for lean and 0.52 for stoichiometric methane/air flames. These values are in agreement with experimental studies that used very different measurement techniques and with results from direct numerical simulations (DNS) reported in the literature.

In this paper LES of flame wall interaction using a non-adiabatic FGM approach is reported for a premixed methane fuel jet impinging on a spherical disk. Nitrogen is used as co-flow in order to avoid the interaction with the surrounding air and combustion. The flow field is described by means of the Smagorinsky model with Germano procedure for SGS stresses. The SGS scalar flux in scalar transport equations is modeled by the linear eddy diffusivity model. Two aspects are especially addressed in this paper. First focus is on the grid resolution required near the wall without including a special wall-adapted SGS modeling in reacting configurations. The second aspect is devoted to the integration of the near wall kinetic effects into the FGM framework. The results for the flow field, mixing and combustion properties are presented and analyzed in terms of grid resolution, Reynolds number (in reacting and non-reacting case) and adiabaticity. Comparisons with available experimental data show satisfactory agreement. An outline of the thermal and flow boundary layer analysis is subsequently provided.

An impinging jet burner was developed to investigate flame-wall interactions (FWI) using laser based diagnostics. CO concentrations were measured with two-photon laser-induced fluorescence (LIF) in combination with coherent anti-Stokes Raman spectroscopy (CARS) gas phase temperature measurements. Besides being the principal factor in chemical kinetics, temperature data is required to correct the CO LIF data for various factors like density variation, quenching and variation in the Boltzmann population. Phosphor thermometry was used to determine surface temperatures of the wall and to estimate the heat flux. In an parameter study Reynolds numbers and fuel equivalence ratio were varied.

Diese Arbeit beschreibt die Basis fur grundlegende Qualitatsanforderungen an chirurgische Abteilungen, welche an der interdisziplinaren Versorgung von Kolon- und Rektumkarzinompatienten beteiligt sind

Background: The modern therapy of early esophageal carcinomas (pT1) requires an excellent cooperation between experienced gastroenterologists, pathologists, and esophageal surgeons. While endoscopic resection (ER) is accepted as the standard curative treatment for mucosal esophageal carcinomas, submucosal tumors are regarded as a strict indication for surgery. There is an ongoing discussion about the operative approach and the extent of lymph node dissection in these cases. Methods: A literature review was performed to evaluate the operative treatment of early esophageal cancer. In view of oncological risk factors, treatment strategies, and operative procedures, current studies are summarized and compared to the results of our own center. Results and Conclusion: In early esophageal cancer, lymph node involvement is the only independent risk factor for survival and recurrence rates. There is evidence that infiltrated lymph nodes (N+) are significantly correlated with tumor infiltration depth, lymphovascular (L1) and microvascular invasion (V1), and poor tumor differentiation (G3). Several studies suggest that early squamous cell carcinomas (eSCCs) and early adenocarcinomas (eACs) have a different tumor biology and therefore need a different treatment strategy. While eSCCs in stage m1 and m2 can be cured by ER, tumors infiltrating the submucosal layer (sm1-3) show a high rate of lymph node metastasis (LNM); thus, surgical resection (SR) is clearly indicated. In tumors with invasion into the deep mucosa (m3) the risk of LNM is up to 11%; however, reliable data are rare and the type of therapy should be discussed with the patients individually. In eACs, ER is the standard curative treatment for all mucosal tumors (m1-m4) and sm1 tumors with low-risk constellation (G1, L0, VO, R0). All high-risk sm1 tumors and those with deeper submucosal infiltration (sm2, sm3) show a high rate of LNM and require SR. The standard operative proce- dure for early esophageal carcinomas is an Ivor-Lewis esophagectomy with radical, at least two-field lymphadenectomy.

Background Newly diagnosed insulin-dependent diabetes mellitus is characterised by a temporary recovery of endogeneous insulin ("remission") after the beginning of medical treatment with subcutaneous insulin injections. Although most diabetologists think, that insulin reserve is related to reduced occurrence of diabetic long-term complications, such as eye, nerve and kidney disease, there is only one prospective controlled clinical study (the DCCT) addressing this question, however as secondary hypothesis. Methods/Design Therefore, we composed a trial consisting of two cohorts with two therapeutic options within each cohort (conventional versus intensive therapy) and a three-year follow-up. In one group the patients are randomly assigned to the treatment regimes to test the statistical alternative hypothesis if variable insulin dosage is superior to fixed insulin injection in preserving insulin reserve measured by C-peptide in serum. Another group includes patients who prefer one of the two therapies, decline randomisation, but consent to follow-up. Apart from the determination of insulin reserve as a biological parameter a second primary endpoint was defined as 'therapeutic failure' according to the criteria of the European Association for the Study of Diabetes. Patients pass a training program to help them self-manage diabetes. A standardised protocol is being set up to minimize centre effects and bias of health care providers. Potential patient dependent bias will be investigated by questionnaires measuring psychic coping processes of people with diabetes. Management of visit dates is directly navigated by the database. Automated visit-reminders are mailed to patients and caregivers to optimise the number of visits on schedule. Data quality is regularly monitored and centres are informed on the results of continuous data management.