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"Koch, Felix"
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A window of opportunity : Europe, Gulf security and the aftermath of the Iraqi war
\"A Window of Opportunity\" is a critical collection of essays that examines the shifting geopolitical landscape of the Middle East in the wake of the 2003 Iraq War. Published as a collaborative effort involving the Gulf Research Center, the volume explores whether the upheaval in Iraq created a \"window\" for the European Union to redefine its strategic role in the Persian Gulf. The contributors analyze the divergence between transatlantic approaches to regional security, contrasting the United States' \"Forward Strategy for Freedom\" with Europe’s emphasis on multilateralism, economic partnership, and institutional reform.
BOOK
A general relationship between disorder, aggregation and charge transport in conjugated polymers
Conjugated polymer chains have many degrees of conformational freedom and interact weakly with each other, resulting in complex microstructures in the solid state. Understanding charge transport in such systems, which have amorphous and ordered phases exhibiting varying degrees of order, has proved difficult owing to the contribution of electronic processes at various length scales. The growing technological appeal of these semiconductors makes such fundamental knowledge extremely important for materials and process design. We propose a unified model of how charge carriers travel in conjugated polymer films. We show that in high-molecular-weight semiconducting polymers the limiting charge transport step is trapping caused by lattice disorder, and that short-range intermolecular aggregation is sufficient for efficient long-range charge transport. This generalization explains the seemingly contradicting high performance of recently reported, poorly ordered polymers and suggests molecular design strategies to further improve the performance of future generations of organic electronic materials.
The recent demonstration that highly disordered polymer films can transport charges as effectively as polycrystalline semiconductors has called into question the relationship between structural order and mobility in organic materials. It is now shown that, in high-molecular-weight polymers, efficient charge transport is allowed due to a network of interconnected aggregates that are characterized by short-range order.
Journal Article
Experience of a serious life event increases the risk for childhood type 1 diabetes: the ABIS population-based prospective cohort study
Aims/hypothesis
The aim of this study was to prospectively investigate whether psychological stress during childhood may be a risk factor for manifest type 1 diabetes.
Methods
The All Babies In Southeast Sweden (ABIS) study invited all families with babies born between 1 October 1997 and 30 September 1999 in southeast Sweden to participate. Our study subsample includes 10,495 participants in at least one of the data collections at 2–3, 5–6, 8 and 10–13 years of age not yet diagnosed with type 1 diabetes at inclusion; 58 children were subsequently diagnosed. Age at diagnosis was obtained from the national register SweDiabKids in 2012. Family psychological stress was measured via questionnaires given to the parents assessing serious life events, parenting stress, parental worries and the parent’s social support.
Results
Childhood experience of a serious life event was associated with a higher risk of future diagnosis of type 1 diabetes (HR 3.0 [95% CI 1.6, 5.6],
p
= 0.001) after adjusting for heredity of type 1 diabetes and age at entry into the study. The result was still valid when controlling for heredity of type 2 diabetes, size for gestational age, the parents’ education level and whether the mother worked at least 50% of full time before the child’s birth (HR 2.8 [95% CI 1.5, 5.4],
p
= 0.002), and also when childhood BMI was added to the model (HR 5.0 [95% CI 2.3, 10.7],
p
< 0.001).
Conclusions/interpretation
This first prospective study concluded that experience of a serious life event in childhood may be a risk factor for manifest type 1 diabetes.
Journal Article
Higher maternal education is associated with favourable growth of young children in different countries
Background Childhood growth affects long-term health and could contribute to health inequalities that persist throughout life. Methods We compared growth data of 4-year-old to 6-year-old children born 1997–2002 in UK (n=15 168), Sweden (n=6749) and rural China (n=10 327). SD scores (SDS) were calculated against the WHO Growth Standard. Obesity and overweight were defined by the International Obesity Taskforce cut-offs, and stunting, underweight and thinness by height, weight or body mass index (BMI)<−2 SDS. Associations with maternal education were standardised by calculating the Slope Index of Inequality (SII). Results Mean SDS height, weight and BMI in the UK (−0.01, 0.42, 0.62, respectively) and Sweden (0.45, 0.59, 0.45) were higher than in China (−0.98, −0.82, −0.29). Higher maternal education was consistently associated with taller offspring height SDS (SII: UK 0.25; Sweden 0.17; China 1.06). Underweight and stunting were less common in the UK (prevalence: 0.6% and 2.2%, respectively) and Sweden (0.3% and 0.6%) than in China (9.5% and 16.4%), where these outcomes were inversely associated with maternal education (SII: −25.8% and −12.7%). Obesity prevalence in the UK, Sweden and China was 4.8%, 3.7% and 0.4%, respectively. Maternal education was inversely associated with offspring obesity in the UK (SII: −3.3%) and Sweden (−2.8%), but not in China (+0.3%). Conclusions Higher maternal education was associated with more favourable growth in young children: lower obesity and overweight in the UK and Sweden, and lower stunting and underweight in rural China. Public health strategies to optimise growth in early childhood need to acknowledge socioeconomic factors, but possibly with a different emphasis in different settings.
Journal Article
The influence of bisphosphonates on viability, migration, and apoptosis of human oral keratinocytes—in vitro study
Bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) is one of the most often seen side effects in patients treated with bisphosphonates, presenting clinically as a non-healing wound. One theory of BP-ONJ etiology describes a negative effect on soft tissues, especially on keratinocytes, which play an important role in oral wound healing and oral soft tissue regeneration. A high cell viability of keratinocytes, which can migrate to the affected location, is essential for wound healing. The aim of this in vitro study was to investigate the effect of differently potent bisphosphonates on human oral keratinocytes (HOK).
Three nitrogen-containing bisphosphonates (ibandronate, pamidronate, and zoledronate) and one non-nitrogen-containing bisphosphonate (clodronate) were compared concerning their potency on cell viability (calcein assay and MTT assay), migration ability (Boyden chamber migration assay and scratch wound proliferation assay), and apoptosis (TUNEL assay) of HOK.
The nitrogen-containing bisphosphonates, particulary highly potent pamidronate and zoledronate preparations, had a strong negative influence on cell viability, migration ability, and apoptosis of HOK. The non-nitrogen-containing clodronate even increased cell viability in higher concentrations.
This study demonstrates that bisphosphonates have a strong influence on HOK on different cellular levels like cell viability, migration ability, and apoptosis rate. The results support the theory that BP-ONJ is a multifactorially caused disease.
Furthermore, this in vitro study confirms the theory that perioperative interruption of bisphosphonate application during dental surgical procedures might be feasible to promote better tissue regeneration and wound healing.
Journal Article
Bone Marrow Concentrate and Bovine Bone Mineral for Sinus Floor Augmentation: A Controlled, Randomized, Single-Blinded Clinical and Histological Trial—Per-Protocol Analysis
Purpose:
The purpose of this work was to evaluate the potential of substituting autogenous bone (AB) by bone marrow aspirate concentrate (BMAC). Both AB and BMAC were tested in combination with a bovine bone mineral (BBM) for their ability of new bone formation (NBF) in a multicentric, randomized, controlled, clinical and histological noninferiority trial.
Materials and Methods:
Forty-five severely atrophied maxillary sinus from 26 patients were evaluated in a partial cross-over design. As test arm, 34 sinus of 25 patients were augmented with BBM and BMAC containing mesenchymal stem cells. Eleven control sinus from 11 patients were augmented with a mixture of 70% BBM and 30% AB. Biopsies were obtained after a 3–4-month healing period at time of implant placement and histomorphometrically analyzed for NBF.
Results:
NBF was 14.3%±1.8% for the control and nonsignificantly lower (12.6%±1.7%) for the test (90% confidence interval: −4.6 to 1.2). Values for BBM (31.3%±2.7%) were significantly higher for the test compared with control (19.3%±2.5%) (p<0.0001). Nonmineralized tissue was lower by 3.3% in the test compared with control (57.6%; p=0.137).
Conclusions:
NBF after 3–4 months is equivalent in sinus, augmented with BMAC and BBM or a mixture of AB and BBM. This technique could be an alternative for using autografts to stimulate bone formation.
Journal Article
Osteonecrosis of the jaw related to sunitinib
Case Report
A 59-year-old male patient was referred to the hospital with exposed bone measuring 10 mm in diameter in the posterior, left-side region of the lower jaw. Two months previous, the first molar had been extracted. The patient had contracted renal cell carcinoma and had been treated by nephrectomy in 2003. Soft tissue metastases occurred. After initial therapy with interferon and vinblastine, a relapse occurred and the therapy was changed to sorafenib, followed by sunitinib. Osteonecrosis of the lower jaw appeared 1 year after initial and exclusive therapy with sunitinib.
Conclusions
Bisphosphonates had never been applied. With increasing application of multi-kinase inhibitors, complications due to osteonecrosis could occur more frequently.
Journal Article
A smart tele-cytology point-of-care platform for oral cancer screening
Early detection of oral cancer necessitates a minimally invasive, tissue-specific diagnostic tool that facilitates screening/surveillance. Brush biopsy, though minimally invasive, demands skilled cyto-pathologist expertise. In this study, we explored the clinical utility/efficacy of a tele-cytology system in combination with Artificial Neural Network (ANN) based risk-stratification model for early detection of oral potentially malignant (OPML)/malignant lesion. A portable, automated tablet-based tele-cytology platform capable of digitization of cytology slides was evaluated for its efficacy in the detection of OPML/malignant lesions (n = 82) in comparison with conventional cytology and histology. Then, an image pre-processing algorithm was established to segregate cells, ANN was trained with images (n = 11,981) and a risk-stratification model developed. The specificity, sensitivity and accuracy of platform/ stratification model were computed, and agreement was examined using Kappa statistics. The tele-cytology platform, Cellscope, showed an overall accuracy of 84-86% with no difference between tele-cytology and conventional cytology in detection of oral lesions (kappa, 0.67-0.72). However, OPML could be detected with low sensitivity (18%) in accordance with the limitations of conventional cytology. The integration of image processing and development of an ANN-based risk stratification model improved the detection sensitivity of malignant lesions (93%) and high grade OPML (73%), thereby increasing the overall accuracy by 30%. Tele-cytology integrated with the risk stratification model, a novel strategy established in this study, can be an invaluable Point-of-Care (PoC) tool for early detection/screening in oral cancer. This study hence establishes the applicability of tele-cytology for accurate, remote diagnosis and use of automated ANN-based analysis in improving its efficacy.
Journal Article
The impact of bisphosphonates on the osteoblast proliferation and Collagen gene expression in vitro
Background
Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are known to be associated with osteonecrosis of the jaw (BONJ).
The objective of this study was to evaluate the effect of bisphosphonates on osteoblast proliferation by cell count and gene expression analysis of cyclin D1
in vitro
. Furthermore, the gene expression of the extracellular matrix protein collagen type I was evaluated. Nitrogen-containing and non-nitrogen-containing bisphosphonates have been compared on gene expression levels.
Methods
Human osteoblast obtained from hip bone were stimulated with zoledronate, ibandronate and clodronate at concentrations of 5 × 10
-5
M over the experimental periods of 1, 2, 5, 10 and 14 days. At each point in time, the cells were dissolved, the mRNA extracted, and the gene expression level of cyclin D1 and collagen type I were quantified by Real-Time RT-PCR. The gene expression was compared to an unstimulated osteoblast cell culture for control.
Results
The proliferation appeared to have been influenced only to a small degree by bisphosphonates. Zolendronate led to a lower cyclin D1 gene expression after 10 days. The collagen gene expression was enhanced by nitrogen containing bisphosphonates, decreased however after day 10. The non-nitrogen-containing bisphosphonate clodronate, however, did not significantly influence cyclin D1 and collagen gene expression.
Conclusions
The above data suggest a limited influence of bisphosphonates on osteoblast proliferation, except for zoledronate. The extracellular matrix production seems to be initially advanced and inhibited after 10 days. Interestingly, clodronate has little influence on osteoblast proliferation and extracellular matrix production in terms of cyclin D1 and collagen gene expression.
Journal Article
Mobile microscopy as a screening tool for oral cancer in India: A pilot study
Oral cancer is the most common type of cancer among men in India and other countries in South Asia. Late diagnosis contributes significantly to this mortality, highlighting the need for effective and specific point-of-care diagnostic tools. The same regions with high prevalence of oral cancer have seen extensive growth in mobile phone infrastructure, which enables widespread access to telemedicine services. In this work, we describe the evaluation of an automated tablet-based mobile microscope as an adjunct for telemedicine-based oral cancer screening in India. Brush biopsy, a minimally invasive sampling technique was combined with a simplified staining protocol and a tablet-based mobile microscope to facilitate local collection of digital images and remote evaluation of the images by clinicians. The tablet-based mobile microscope (CellScope device) combines an iPad Mini with collection optics, LED illumination and Bluetooth-controlled motors to scan a slide specimen and capture high-resolution images of stained brush biopsy samples. Researchers at the Mazumdar Shaw Medical Foundation (MSMF) in Bangalore, India used the instrument to collect and send randomly selected images of each slide for telepathology review. Evaluation of the concordance between gold standard histology, conventional microscopy cytology, and remote pathologist review of the images was performed as part of a pilot study of mobile microscopy as a screening tool for oral cancer. Results indicated that the instrument successfully collected images of sufficient quality to enable remote diagnoses that show concordance with existing techniques. Further studies will evaluate the effectiveness of oral cancer screening with mobile microscopy by minimally trained technicians in low-resource settings.
Journal Article