Combining amperometry and mass spectrometry as a dual detection approach for capillary electrophoresis.

Dual detection concepts (DDCs) are becoming more and more popular in analytical chemistry. In this work, we describe a novel DDC for capillary electrophoresis (CE) consisting of an amperometric detector (AD) and a mass spectrometer (MS). This detector combination has a good complementarity as the AD exhibits high sensitivity, whereas the MS provides excellent selectivity. Both detectors are based on a destructive detection principle, making a serial detector arrangement impossible. Thus, for the realization of the DDC, the CE flow was divided into two parts with a flow splitter. The DDC was characterized in a proof-of-concept study with ferrocene derivates and a nonaqueous background electrolyte. We could show that splitting the CE flow was a suitable method for the instrumental realization of the DDC consisting of two destructive detectors. By lowering the height of the AD compared to the MS, it was possible to synchronize the detector responses. Additionally, for the chosen model system, we confirmed that the AD was much more reproducible and had lower limits of detection (LODs) than the MS. The LODs were identical for the DDC and the single-detection arrangements, indicating no sensitivity decrease due to the CE flow splitting. The DDC was successfully applied to determine the drug and doping agent trimetazidine.

Dead volume-free flow splitting in capillary electrophoresis.

In recent years, several dual detection concepts (DDCs) for CE were developed, which consisted of at least one nondestructive detector. For these DDCs, a linear detector arrangement could be used, which is not possible when both detectors are destructive. To overcome this problem, we developed a concept for the splitting of the CE stream utilizing commercially available flow splitters (FSs) that allow the parallel positioning of two destructive detectors. In this proof-of-concept study, T- and Y-shaped FSs were characterized regarding their suitability for DDCs. To keep it simple, a UV detector (UV) and a C4 D were used for the characterization. The model system consisted of an acetonitrile-based background electrolyte and the two model substances, (ferrocenylmethyl)trimethylammonium iodide and caffeine. CE hyphenated to a UV detector (CE-UV) measurements revealed that the split ratio was about 50% for both FSs. CE-C4 D was used to evaluate the peak shape in front of and behind the FSs. These measurements showed that there was no significant peak broadening introduced by the FSs. Additionally, there were no changes in the LODs in front of and behind the FSs. Furthermore, the flexibility of the new FS approach allowed the usage of capillaries with different ids (25-75 µm) for injection and detection.

Carbonaceous Oxygen Evolution Reaction Catalysts: From Defect and Doping-Induced Activity over Hybrid Compounds to Ordered Framework Structures.

Oxygen evolution reaction (OER) is expected to be of great importance for the future energy conversion and storage in form of hydrogen by water electrolysis. Besides the traditional noble-metal or transition metal oxide-based catalysts, carbonaceous electrocatalysts are of great interest due to their huge structural and compositional variety and unrestricted abundance. This review provides a summary of recent advances in the field of carbon-based OER catalysts ranging from "pure" or unintentionally doped carbon allotropes over heteroatom-doped carbonaceous materials and carbon/transition metal compounds to metal oxide composites where the role of carbon is mainly assigned to be a conductive support. Furthermore, the review discusses the recent developments in the field of ordered carbon framework structures (metal organic framework and covalent organic framework structures) that potentially allow a rational design of heteroatom-doped 3D porous structures with defined composition and spatial arrangement of doping atoms to deepen the understanding on the OER mechanism on carbonaceous structures in the future. Besides introducing the structural and compositional origin of electrochemical activity, the review discusses the mechanism of the catalytic activity of carbonaceous materials, their stability under OER conditions, and potential synergistic effects in combination with metal (or metal oxide) co-catalysts.

Tin Oxide Based Nanomaterials and Their Application as Anodes in Lithium-Ion Batteries and Beyond.

Herein, recent progress in the field of tin oxide (SnO2 )-based nanosized and nanostructured materials as conversion and alloying/dealloying-type anodes in lithium-ion batteries and beyond (sodium- and potassium-ion batteries) is briefly discussed. The first section addresses the importance of the initial SnO2 micro- and nanostructure on the conversion and alloying/dealloying reaction upon lithiation and its impact on the microstructure and cyclability of the anodes. A further section is dedicated to recent advances in the fabrication of diverse 0D to 3D nanostructures to overcome stability issues induced by large volume changes during cycling. Additionally, the role of doping on conductivity and synergistic effects of redox-active and -inactive dopants on the reversible lithium-storage capacity and rate capability are discussed. Furthermore, the synthesis and electrochemical properties of nanostructured SnO2 /C composites are reviewed. The broad research spectrum of SnO2 anode materials is finally reflected in a brief overview of recent work published on Na- and K-ion batteries.

Oriented Films of Conjugated 2D Covalent Organic Frameworks as Photocathodes for Water Splitting.

Light-driven water electrolysis at a semiconductor surface is a promising way to generate hydrogen from sustainable energy sources, but its efficiency is limited by the performance of available photoabsorbers. Here we report the first time investigation of covalent organic frameworks (COFs) as a new class of photoelectrodes. The presented 2D-COF structure is assembled from aromatic amine-functionalized tetraphenylethylene and thiophene-based dialdehyde building blocks to form conjugated polyimine sheets, which π-stack in the third dimension to create photoactive porous frameworks. Highly oriented COF films absorb light in the visible range to generate photoexcited electrons that diffuse to the surface and are transferred to the electrolyte, resulting in proton reduction and hydrogen evolution. The observed photoelectrochemical activity of the 2D-COF films and their photocorrosion stability in water pave the way for a novel class of photoabsorber materials with versatile optical and electronic properties that are tunable through the selection of appropriate building blocks and their three-dimensional stacking.

Hormonal receptor status, Ki-67 and HER2 expression: Prognostic value in the recurrence of ductal carcinoma in situ of the breast?

PURPOSE: Local recurrence is considered a major concern in patients diagnosed with ductal carcinoma in situ (DCIS), as its invasive occurrence is associated with high rates of distant disease and mortality. This study aims to assess the possible correlation of hormonal receptor status, Ki-67 and HER2 expression with recurrence rates in women with DCIS, taking also into account the potential prognostic effects of grade and age at diagnosis. METHODS: 230 consecutive patients with DCIS were included in this study. Invasive and non-invasive recurrence events were recorded, as a total. Clinicopathological information, as well as PR positivity, ER positivity, HER2 positivity and ki-67 expression were analyzed. Multivariable Cox regression analysis was performed, examining the risk factors for recurrence. RESULTS: Recurrence was noted in 17.8% of cases; the median follow-up was 44 months. Higher grade (adjusted HR = 1.72, 95%CI: 1.06-2.78), age at diagnosis (adjusted HR = 0.60, 95%CI: 0.43-0.83), Ki-67 expression (adjusted HR = 1.78, 95%CI: 1.11-2.88), and type of administered treatment were independently associated with increased recurrence rates. Recurrence rates were not significantly associated with ER, PR status or HER2 expression. CONCLUSION: In addition to high grade, administered treatment and younger age at diagnosis, high Ki-67 expression seems to be independently associated with increased likelihood of recurrence in patients with DCIS. Future studies with additional molecular markers seem necessary to further improve the identification of high-risk patients for DCIS recurrence.

Prognostic influence of cyclooxygenase-2 protein and mRNA expression in node-negative breast cancer patients.

BACKGROUND: Cyclooxygenases (COX) play a key role in prostaglandin metabolism and are important for tumor development and progression. The aim of this study was to analyze the prognostic impact of COX-2 expression in a cohort of lymph node-negative breast cancer patients not treated in the adjuvant setting. METHODS: COX-2 expression was determined by immunohistochemistry (IHC) in tumor tissue of 193 node-negative breast cancer patients. Additionally, mRNA expression was determined in corresponding tumor samples using microarray based gene-expression data. Univariate and multivariate Cox regression analyses adjusted for age at diagnosis, tumor size, histological grade, human epithelial growth factor receptor 2 (HER2), estrogen receptor (ER) and progesterone receptor (PR) were performed to evaluate the association of both COX-2 protein and mRNA expression with survival. Survival rates were determined by the Kaplan-Meier method. Correlations between COX-2 expression and established prognostic factors were analyzed using the Chi-square test. A potential correlation between COX-2 protein expression and COX-2 mRNA expression was assessed utilizing the Kruscal-Wallis-H-test. RESULTS: COX-2 protein expression was positive in 24.9% of the breast cancer samples. Univariate analysis showed that COX-2 protein expression was associated with shorter disease-free survival (DFS) (P = 0.0001), metastasis-free survival (MFS) (P = 0.002) as well as breast cancer specific overall survival (OS) (P = 0.043). In multivariate analysis COX-2 expression retained its significance independent of established prognostic factors for shorter DFS (P < 0.001, HR = 2.767, 95% CI = 1.563-4.901) and for inferior MFS (P = 0.002, HR = 2.7, 95% CI = 1.469-5.263) but not for OS (P = 0.096, HR = 1.929, 95% CI = 0.889-4.187). In contrast, COX-2 mRNA expression was not related to survival and failed to show a correlation with protein expression (P = 0.410). CONCLUSIONS: The present findings support the hypothesis that COX-2 protein but not mRNA expression is associated with an unfavorable outcome in node-negative breast cancer.

Nationwide analysis on surgical staging procedures and systemic treatment for patients with endometrial cancer in Germany.

OBJECTIVE: In 2009 and 2006, the Arbeitsgemeinschaft Gynäkologische Onkologie evaluated therapeutic approaches for endometrial carcinoma (EC) in Germany. METHODS AND MATERIALS: A questionnaire was developed and sent to 775 German gynecologic departments in 2009 (500 in 2006). The results of the questionnaires were compared with each other and with the recommendations of the Arbeitsgemeinschaft Gynäkologische Onkologie's guideline. Subgroup analyses were performed, dividing the participating centers into small and large centers and into centers with less and more experience with EC. RESULTS: Responses were available in 33.3% in 2009 and 35.8% in 2006. Comparing 2009 with 2006, it became apparent that peritoneal washing cytology was performed in 94.6% versus 86.9% (P = 0.008), pelvic lymphadenectomy (LAN) in 98.3% versus 95.3%, and paraaortic LAN in 90.2% versus 73.8% (P < 0.001) for endometrioid EC, and LAN for histologic high-risk subtypes of EC in 99.6% versus 94.2% (P = 0.001), respectively. In 2009, all these criteria met the recommendation of the guidelines. Reoperation for LAN after postoperative upstaging was performed in 66.1% versus 50.6% (P = 0.002), and adjuvant systemic treatment with chemotherapy and endocrine therapy was performed in 63.7% versus 48.8% (P = 0.003) and 25.7% versus 15.4% (P = 0.014), respectively. This showed nonadherence to the guidelines. Laparoscopic approach was performed in 30.4% versus 19.7% (P = 0.014) of the participating centers, respectively. In subgroup analysis, laparoscopic approach showed a significant difference between small centers (11.5%) and large centers (27.3%) in 2006 (P = 0.012). CONCLUSIONS: German hospitals increasingly follow the guidelines concerning LAN and peritoneal washing cytology. However, recommendations concerning reoperating in upstaged patients and adjuvant treatment decisions do not meet the guidelines, thus underlining great uncertainties in this field of gynecologic oncology.

Comparison of tear protein levels in breast cancer patients and healthy controls using a de novo proteomic approach.

Noninvasive biomarkers are urgently needed for early detection of breast cancer since the risk of recurrence, morbidity and mortality are closely related to disease stage at the time of primary surgery. In the past decade, many proteomics-based approaches were developed that utilize the protein profiling of human body fluids or identification of putative biomarkers to obtain more knowledge on the effects of cancer emergence and progression. Herein, we report on an analysis of proteins in the tear fluid from breast carcinoma patients and healthy women using a de novo proteomic approach and 25 mixed samples from each group. This study included 25 patients with primary invasive breast carcinoma and 25 age-matched healthy controls. We performed a MALDI-TOF-TOF-driven semi-quantitative comparison of tear protein levels in cancer (CA) and control (CTRL) using a de novo approach in pooled samples. Over 150 proteins in the tear fluid of CTRL and CA were identified. Using an in-house-developed algorithm we found more than 20 proteins distinctly upregulated or downregulated in the CTRL and CA groups. We identified several proteins that had modified expression in breast cancer patients. These proteins are involved in host immune system pathways (e.g., C1Q1 or S100A8) and different metabolic cascades (ALDH3A or TPI). Further validation of the results in an independent population combined with individual protein profiling of participants is needed to confirm the specificity of our findings and may lead to a better understanding of the pathological mechanism of breast cancer.

Antibody microarray analysis of the serum proteome in primary breast cancer patients.

Noninvasive biomarkers are urgently needed for detecting breast cancer as early as possible since the risk of recurrence, morbidity, and mortality is closely related to disease stage at the time of primary surgery. There are currently no such biomarkers in clinical use as a diagnostic tool. Proteomic analysis of protein expression patterns in body fluids has potential for use in identifying biomarkers of breast cancer. The aim of this study was to compare protein expression levels in the sera of primary breast cancer patients and healthy controls. An antibody microarray tool with 23 antibodies immobilized on nitrocellulose slides was used to determine the levels of acute phase proteins, interleukins, and complement factors in the sera of 101 study participants (49 women with primary breast cancer and 52 healthy age-matched controls). Statistical analysis of reaction intensities identified 6 proteins that showed significantly (p < 0.05) different levels in breast cancer patients vs. healthy subjects. The neural network distinguished cancer patients from controls with a sensitivity of 69% and a specificity of 76%. Thus, antibody microarray analysis could be used as a tool for the development of improved diagnostics and biomarker discovery for breast cancer patients. Further validation of the results and de novo screening of new biomarkers could facilitate the early diagnosis of breast cancer.

Serum proteome profiling of primary breast cancer indicates a specific biomarker profile.

Non-invasive biomarkers for early breast cancer detection are urgently needed, as the risk of recurrent morbidity and mortality is closely related to the stage of the disease at the time of primary surgery. Currently, there are no established clinical biomarkers for breast cancer. Evaluation of protein expression patterns in body fluids using proteomic technologies can be used to discover new biomarkers for the detection of breast cancer. The aim of this study was to identify a biomarker signature identifying primary non-metastatic breast cancer and healthy controls. We screened 91 serum samples including 45 breast cancer patients and 46 healthy women using a proteomic approach. We found 14 biomarkers whose combination detects breast cancer patients from non-cancer controls with a sensitivity of 89% and specificity of 67%. Five biomarkers were comparable with previously identified proteins from published data using similar approaches. This biomarker panel allows accurate discrimination between breast cancer and healthy individuals. In addition, it could distinguish subgroups of breast cancer based on patterns of several specific biomarkers. Further validation of biomarkers could potentially facilitate the early diagnosis of breast cancer as an aid to imaging diagnostics.

Ep-CAM RNA expression predicts metastasis-free survival in three cohorts of untreated node-negative breast cancer.

Epithelial cell adhesion molecule (Ep-CAM) recently received increased attention as a prognostic factor in breast cancer. We aimed to validate the influence of Ep-CAM RNA expression in untreated node-negative breast cancer. Ep-CAM RNA expression was evaluated utilizing microarray-based gene-expression profiling in 194 consecutive node-negative breast cancer patients with long-term follow-up not treated in the adjuvant setting. The prognostic significance of Ep-CAM RNA expression for disease-free survival (DFS), metastasis-free survival (MFS), and breast cancer-specific overall survival (OS) was evaluated in univariate and multivariate analysis adjusted for age, grading, pTstage, ER as well as PR receptor and HER-2 status. Additionally, Ep-CAM RNA expression was compared with immunohistochemistry (IHC) for Ep-CAM in 194 patients. The prognostic impact of Ep-CAM gene expression was validated in further 588 node-negative breast cancer patients. Levels of Ep-CAM RNA expression showed a significant correlation with IHC (P = 0.001) and predicted in univariate analysis DFS (P = 0.001, HR = 2.4), MFS (P = 0.003, HR = 2.5), and OS (P = 0.002, HR = 3.1) accurately. The prognostic influence of Ep-CAM RNA was significant also in multivariate analysis for DFS (P = 0.017, HR = 2.0), MFS (P = 0.049, HR = 1.9), and OS (P = 0.042, HR = 2.3), respectively. The association with MFS was confirmed in an independent validation cohort in univariate (P = 0.006, HR = 1.9) and multivariate (P = 0.035, HR = 1.7) analysis. Ep-CAM RNA correlated with the proliferation metagene (P < 0.001, R=0.425) Nevertheless, in multivariate analysis, Ep-CAM was associated with MFS independent from the proliferation metagene (P = 0.030, HR = 1.8). In conclusion, Ep-CAM RNA expression is associated with poor MFS in three cohorts of untreated node-negative breast cancer.

The humoral immune system has a key prognostic impact in node-negative breast cancer.

Estrogen receptor (ER) expression and proliferative activity are established prognostic factors in breast cancer. In a search for additional prognostic motifs, we analyzed the gene expression patterns of 200 tumors of patients who were not treated by systemic therapy after surgery using a discovery approach. After performing hierarchical cluster analysis, we identified coregulated genes related to the biological process of proliferation, steroid hormone receptor expression, as well as B-cell and T-cell infiltration. We calculated metagenes as a surrogate for all genes contained within a particular cluster and visualized the relative expression in relation to time to metastasis with principal component analysis. Distinct patterns led to the hypothesis of a prognostic role of the immune system in tumors with high expression of proliferation-associated genes. In multivariate Cox regression analysis, the proliferation metagene showed a significant association with metastasis-free survival of the whole discovery cohort [hazard ratio (HR), 2.20; 95% confidence interval (95% CI), 1.40-3.46]. The B-cell metagene showed additional independent prognostic information in carcinomas with high proliferative activity (HR, 0.66; 95% CI, 0.46-0.97). A prognostic influence of the B-cell metagene was independently confirmed by multivariate analysis in a first validation cohort enriched for high-grade tumors (n = 286; HR, 0.78; 95% CI, 0.62-0.98) and a second validation cohort enriched for younger patients (n = 302; HR, 0.83; 95% CI, 0.7-0.97). Thus, we could show in three cohorts of untreated, node-negative breast cancer patients that the humoral immune system plays a pivotal role in metastasis-free survival of carcinomas of the breast.