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1.
Nanoscale ; 12(25): 13407-13413, 2020 Jul 02.
Article in English | MEDLINE | ID: mdl-32614013

ABSTRACT

Recently, several theoretical predictions have been made about 2D planar FeC, CoC, NiC, and CuC, while their bulk phases still remain unknown. Here, we present a generalization of the 2D family of 3d transition metal monocarbides (TMC) by searching for their stable configurations with DFT methods and an evolutionary algorithm. It is found that in the TMC row (TM = Sc-Cu) the tendency of 3D rocksalt phase formation is monotonously interchanged with 2D phase appearance, namely, planar orthorhombic TMC characterized by carbon dimers inside metal hexagons. Among them, orthorhombic CoC and FeC monocarbides would likely be formed rather than any other 2D metal carbide phase or metal/graphene interface.

2.
Chirurg ; 90(4): 293-298, 2019 Apr.
Article in German | MEDLINE | ID: mdl-30182266

ABSTRACT

BACKGROUND: The surgical treatment of obesity in Germany is a rapidly developing field which is strictly controlled by national guidelines. OBJECTIVE: Depiction of the burden on obesity centers by the exponential increase in numbers of patients following bariatric treatment. METHODS: In a retrospective study the numbers of outpatients at this university obesity center (founded 2007) were descriptively analyzed. Outpatient visits were documented annually and divided into two groups: primary visit and follow-up visit. The frequency of bariatric operations as well as their acceptance/cost coverage by health insurances were evaluated. RESULTS: Overall 318 patients were seen in 2007: 156 primary and 162 follow-up visits. The health insurance rejection rate for cost coverage was 16.8%. There were 1691 outpatient visits in 2016 (2016 vs. 2007: +532%), of which 487 (+312%) were primary and 1204 (+743%) follow-up visits. The health insurance rejection rate dropped to 1.8%, while the frequency of operations increased nearly tenfold. CONCLUSION: With the increasing acceptance of bariatric surgery, a relatively low number of specialized centers have to deal with an exponentially rising follow-up frequency. In consideration of the extent of the obesity epidemic an adequate follow-up constitutes a socioeconomic problem, which can only be solved in an interdisciplinary setting under structural integration.


Subject(s)
Aftercare , Bariatric Surgery , Obesity, Morbid , Germany , Humans , Obesity, Morbid/surgery , Retrospective Studies
3.
Br J Surg ; 105(6): 677-685, 2018 05.
Article in English | MEDLINE | ID: mdl-29579336

ABSTRACT

BACKGROUND: Surgical approaches to autoimmune thyroid disease are currently hampered by concerns over postoperative complications. Risk profiles and incidences of postoperative complications have not been investigated systematically, and studies with sufficient power to show valid data have not been performed. METHODS: A prospective multicentre European study was conducted between July 2010 and December 2012. Questionnaires were used to collect data prospectively on patients who had surgery for autoimmune thyroid disease and the findings were compared with those of patients undergoing surgery for multinodular goitre. Logistic regression analysis was used to evaluate risk factors for thyroid surgery-specific complications, transient and permanent recurrent laryngeal nerve (RLN) palsy and hypoparathyroidism. RESULTS: Data were available for 22 011 patients, of whom 18 955 were eligible for analysis (2488 who had surgery for autoimmune thyroid disease and 16 467 for multinodular goitre). Surgery for multinodular goitre and that for autoimmune thyroid disease did not differ significantly with regard to general complications. With regard to thyroid surgery-specific complications, the rate of temporary and permanent vocal cord palsy ranged from 2·7 to 6·7 per cent (P = 0·623) and from 0·0 to 1·4 per cent (P = 0·600) respectively, whereas the range for temporary and permanent hypoparathyroidism was 12·9 to 20·0 per cent (P < 0·001) and 0·0 to 7·0 per cent (P < 0·001) respectively. In logistic regression analysis of transient and permanent vocal cord palsy, autoimmune thyroid disease was not an independent risk factor. Autoimmune thyroid disease, extent of thyroid resection, number of identified parathyroid glands and no autotransplantation were identified as independent risk factors for both transient and permanent hypoparathyroidism. CONCLUSION: Surgery for autoimmune thyroid disease is safe in comparison with surgery for multinodular goitre in terms of general complications and RLN palsy. To avoid the increased risk of postoperative hypoparathyroidism, special attention needs to be paid to the parathyroid glands.


Subject(s)
Graves Disease/surgery , Hashimoto Disease/surgery , Postoperative Complications/etiology , Thyroidectomy/adverse effects , Thyroiditis, Subacute/surgery , Adult , Age Factors , Female , Goiter, Nodular/surgery , Humans , Logistic Models , Male , Middle Aged , Prospective Studies , Risk Factors , Thyroidectomy/methods
4.
BMC Complement Altern Med ; 17(1): 237, 2017 Apr 28.
Article in English | MEDLINE | ID: mdl-28454538

ABSTRACT

BACKGROUND: The hydrophobic triterpenes, oleanolic and betulinic acid as well as the hydrophilic mistletoe lectins and viscotoxins possess anticancer properties. They do all occur in combination in European mistletoe (Viscum album L.). Commercial Viscum album L. extracts are aqueous, excluding the insoluble triterpenes. We have previously shown that mistletoe lectins and triterpene acids are effective against Ewing sarcoma in vitro, ex vivo and in vivo. METHODS: We recreated a total mistletoe effect (viscumTT) by combining an aqueous extract (viscum) and a triterpene extract (TT) solubilised with cyclodextrins and analysed the effects of viscumTT and the single extracts on TC-71 Ewing sarcoma cells in vitro by transcriptomic and proteomic profiling. RESULTS: Treatment with the extracts strongly impacted Ewing sarcoma cell gene and protein expression. Apoptosis-associated and stress-activated genes were upregulated, proteasomal protein abundance enhanced and ribosomal and spliceosomal proteins downregulated. The mechanism of action of viscum, TT and viscumTT in TC-71 and MHH-ES-1 cells suggests the involvement of the unfolded protein response. While viscum and viscumTT extract treatment indicate response to oxidative stress and activation of stress-mediated MAPK signalling, TT extract treatment suggests the involvement of TLR signalling and autophagy. CONCLUSIONS: Since the combinatory extract viscumTT exerts highly effective pro-apoptotic effects on Ewing sarcoma cells in vitro, this phytopolychemotherapy could be a promising adjuvant therapeutic option for paediatric patients with Ewing sarcoma.


Subject(s)
Oxidative Stress/drug effects , Plant Extracts/pharmacology , Plant Lectins/pharmacology , Plant Proteins/pharmacology , Sarcoma, Ewing/metabolism , Triterpenes/pharmacology , Viscum album/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Antineoplastic Agents, Phytogenic/therapeutic use , Apoptosis , Autophagy , Cell Proliferation , Humans , Mitogen-Activated Protein Kinases/metabolism , Neoplasm Proteins/metabolism , Oleanolic Acid/pharmacology , Oleanolic Acid/therapeutic use , Pentacyclic Triterpenes , Phytotherapy , Plant Extracts/therapeutic use , Plant Lectins/therapeutic use , Plant Proteins/therapeutic use , Proteasome Endopeptidase Complex/metabolism , Proteome , Proteomics , Sarcoma, Ewing/drug therapy , Signal Transduction , Transcriptome , Triterpenes/therapeutic use , Tumor Cells, Cultured , Betulinic Acid
5.
Zentralbl Chir ; 142(1): 20-22, 2017 Feb.
Article in German | MEDLINE | ID: mdl-27300588

ABSTRACT

The frequency of bariatric operations has increased in Germany. Primary operations are usually performed at specialised centres. However, late complications may develop months or even years after the operation, and every general and visceral surgeon may be confronted with them, regardless of the size and specialisation of their clinics. The laparoscopic Roux-Y gastric bypass is the most frequently performed bariatric operation worldwide. During this procedure, the alimentary loop is lifted up in front of the colon to form a pouch, which creates a mesenteric space, also called the Petersen space, dorsal to the alimentary loop and below the transverse colon. Both here and around the mesenteric space of the Roux anastomosis, an internal hernia may develop, i.e. the small intestine can twist on its own axis. Abdominal discomfort due to intestinal obstruction is unspecific, but very pronounced. Clinically, patients either present with an acute abdomen or with intermittent unspecific abdominal pain with nausea, and rarely also with vomiting. Clinical examinations and lab chemistry tests usually do not reveal any indicative findings. In cases of doubt, therefore, contrast-enhanced computed tomography of the abdomen is the diagnostic imaging procedure of choice. A diagnostic laparoscopy should be performed in every patient with a clinical suspicion of an internal hernia, even if the CT scan is unremarkable. This should be done by a surgeon who is well-versed in laparoscopy and experienced in bariatric surgery, since classification of the intestinal loops is very difficult without knowledge of the hernial orifices. First, an inframesocolic view is obtained with the transverse colon being lifted. From here, the open Petersen space offers a direct view of the ligament of Treitz from the right side. If small intestine is found to the right of the ligament, there is a Petersen hernia. After the inframesocolic view, the gastroenterostomy should be located and the alimentary loop should be followed in distal direction towards the jejunojejunostomy, where the second possible space may be found. Once both spaces have been located and a hernia has been reduced as appropriate, the spaces should be closed with non-absorbable suture.


Subject(s)
Gastric Bypass/adverse effects , Herniorrhaphy/methods , Incisional Hernia/surgery , Laparoscopy/adverse effects , Diagnosis, Differential , Humans , Incisional Hernia/diagnosis , Incisional Hernia/etiology , Interdisciplinary Communication , Intersectoral Collaboration , Intestinal Obstruction/diagnosis , Intestinal Obstruction/etiology , Intestinal Obstruction/surgery , Referral and Consultation , Tomography, X-Ray Computed
6.
Phys Chem Chem Phys ; 17(43): 28770-3, 2015 Nov 21.
Article in English | MEDLINE | ID: mdl-26446929

ABSTRACT

Here we propose a completely new covalent heterostructure based on graphene and self-decorated MoS2 monolayers. Detailed investigation of the decoration process of the MoS2 surface by Mo adatoms was performed using first principles DFT methods. Comparison between valence-only and semicore pseudopotentials was performed to correctly describe the interaction between Mo adatoms and the MoS2 surface. It was found that self-decoration by Mo atoms is favorable from an energetic point of view. We studied in detail various decoration paths of Mo atoms on the MoS2 surface. The strong variation of electronic properties after the decoration of MoS2 was found. The impact of the presence of Mo adatoms on the electronic properties of the graphene/MoS2 heterostructure was shown.


Subject(s)
Disulfides/chemistry , Graphite/chemistry , Models, Theoretical , Molybdenum/chemistry , Surface Properties
7.
Cell Prolif ; 48(5): 600-10, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26300346

ABSTRACT

OBJECTIVES: Osteosarcoma is the most common type of malignant bone tumour in children and adolescents; it has poor prognosis, is highly metastatic and is resistant to current therapeutic approaches. In this study, different herbal extracts used in phytotherapy have been screened after searching innovative natural anti-cancer components. MATERIALS AND METHODS: Twenty steroid glycosides were examined for accordance to their potential of inhibiting cell proliferation and inducing apoptosis in the osteosarcoma cell line 143B. Cell proliferation was examined using a CASY counter. Effects of cardiac glycosides on induction of apoptosis were evaluated by Annexin V-APC and flow cytometry, caspase activity assay and measurement of mitochondrial membrane potential. RESULTS: The study revealed that various steroid glycosides suppress cell proliferation in a concentration-dependent manner. Further investigations indicated apoptotic induction by 17 of the 20 tested cardenolides and bufadienolides. Bufadienolide proscillaridin A, arenobufagin, and cardenolides evomonoside, convallatoxol and ouabain waged strongest apoptotic induction, associated with breakdown of mitochondrial membrane potential and activation of caspases -8 and -9. In contrast, the bufadienolide resibufogenin and cardenolide uzarin had no effect on proliferation inhibition, apoptotic induction or change in mitochondrial membrane potential. CONCLUSION: These results indicate that bufadienolides proscillaridin A and arenobufagin and cardenolide evomonoside, or related natural compounds might be promising new starting points for development of novel anti-cancer agents for treatment of osteosarcoma.


Subject(s)
Apoptosis/drug effects , Cell Proliferation/drug effects , Glycosides/pharmacology , Bone Neoplasms/metabolism , Bone Neoplasms/pathology , Caspase 8/metabolism , Caspase 9/metabolism , Cell Line, Tumor , Glycosides/chemistry , Humans , Membrane Potential, Mitochondrial/drug effects , Osteosarcoma/metabolism , Osteosarcoma/pathology , Steroids/chemistry
8.
Article in English | MEDLINE | ID: mdl-25861369

ABSTRACT

Background. Stress and health-related quality of life are important constructs used in treatment evaluation today. This study is based on a randomised controlled trial examining the stress-reducing effect of eurythmy therapy in comparison with step aerobics in 106 healthy but stressed subjects. The aim of the analysis was to characterise changes in the subjective perceptions of the participants. Methods. Interviews were conducted with 76 healthy adults, 36 (f = 31/m = 5) from the eurythmy group and 40 (f = 28/m = 12) from the step aerobics group both analysed by content analysis and phenomenologically. Results. The following categories were identified for the eurythmy therapy group: enabling a productive therapeutic response, emergence of a new perceptual space, reevaluation of the accustomed perception, and emergence of new options for action. Step aerobics places increased physical and intellectual demands. These are perceived differently as pleasant and relaxing, insufficiently challenging and/or boring, and too challenging and thus experienced as stress-enhancing. Conclusion. The qualitative results provided revealing insights into the profound effects of and subjective assignments of meaning to external and internal stress factors. Processes of mental reinterpretation leading to stress reduction can be stimulated by physical procedures such as eurythmy therapy.

9.
Mol Plant Microbe Interact ; 27(9): 901-12, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24905398

ABSTRACT

Pectin in the primary plant cell wall is thought to be responsible for its porosity, charge density, and microfibril spacing and is the main component of the middle lamella. Plant-parasitic nematodes secrete cell wall-degrading enzymes that macerate the plant tissue, facilitating the penetration and migration within the roots. In sedentary endoparasitic nematodes, these enzymes are released only during the migration of infective juveniles through the root. Later, nematodes manipulate the expression of host plant genes, including various cell wall enzymes, in order to induce specific feeding sites. In this study, we investigated expression of two Arabidopsis pectate lyase-like genes (PLL), PLL18 (At3g27400) and PLL19 (At4g24780), together with pectic epitopes with different degrees of methylesterification in both syncytia induced by the cyst nematode Heterodera schachtii and giant cells induced by the root-knot nematode Meloidogyne incognita. We confirmed upregulation of PLL18 and PLL19 in both types of feeding sites with quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and in situ RT-PCR. Furthermore, the functional analysis of mutants demonstrated the important role of both PLL genes in the development and maintenance of syncytia but not giant cells. Our results show that both enzymes play distinct roles in different infected root tissues as well as during parasitism of different nematodes.


Subject(s)
Arabidopsis/enzymology , Host-Parasite Interactions , Plant Diseases/parasitology , Polysaccharide-Lyases/metabolism , Tylenchida/physiology , Tylenchoidea/physiology , Animals , Arabidopsis/cytology , Arabidopsis/genetics , Arabidopsis/parasitology , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Cell Wall/metabolism , Female , Gene Expression Regulation, Plant , Genes, Reporter , Giant Cells/cytology , Male , Mutagenesis, Insertional , Phenotype , Plant Roots/cytology , Plant Roots/enzymology , Plant Roots/genetics , Plant Roots/parasitology , Plant Shoots/cytology , Plant Shoots/enzymology , Plant Shoots/genetics , Plant Shoots/parasitology , Polysaccharide-Lyases/genetics , Seedlings/cytology , Seedlings/enzymology , Seedlings/genetics , Seedlings/parasitology , Species Specificity , Tylenchida/cytology , Tylenchoidea/cytology , Up-Regulation
10.
Adv Mater ; 24(24): 3239-45, 2012 Jun 26.
Article in English | MEDLINE | ID: mdl-22589176

ABSTRACT

Using atomistic simulations, this work indicates that cement nanotubes can exist. The chemically compatible nanotubes are constructed from the two main minerals in ordinary Portland cement pastes, namely calcium hydroxide and a calcium silicate hydrate called tobermorite. These results show that such nanotubes are stable and have outstanding mechanical properties, unique characteristics that make them ideally suitable for nanoscale reinforcements of cements.


Subject(s)
Construction Materials , Nanotubes/chemistry , Elasticity , Tensile Strength
11.
Cell Prolif ; 45(2): 176-87, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22221251

ABSTRACT

OBJECTIVES: Aqueous Viscum album L. extracts are widely used for anti-cancer therapies. Due to their low solubility, triterpenes (which are known to act on cancers), do not occur in aqueous extracts in significant amounts. Using cyclodextrins, we have found it possible to solubilize mistletoe triterpene acids and to determine their effects on acute lymphoblastic leukaemia (ALL) in vitro and in vivo. MATERIALS AND METHODS: A C.B-17/SCID model of pre-B ALL (NALM-6) was used to test efficacy and mechanisms of treatment with lectin- and triterpene acid containing preparations in vivo. Cytotoxicity of increasing concentrations of V. album L. preparations was assessed in vitro. Apoptosis was determined using mitochondrial membrane potential measurements, annexin V/PI, western blot analyses and caspase inhibitor assays. RESULTS: Solubilized triterpene acid- or lectin-containing V. album L. extracts inhibited cell proliferation and demonstrated cytotoxic properties in vitro. Annexin V/PI and mitochondrial membrane potential assays indicated that dose-dependent induction of apoptosis was the main mechanism. Combination (viscumTT) of lectin- (viscum) and triterpene-containing (TT) extracts resulted in greatest induction of apoptosis. Furthermore, caspase activity demonstrated that these extracts were able to induce apoptosis through both caspase-8 and -9 dependent pathways. In vivo experimentation showed that treatment of mice with viscumTT combination prolonged mean survival to 50.5 days compared to 39.3 days in the phosphate-buffered saline group. CONCLUSION: Here for the first time, we have demonstrated that either solubilized triterpene acids or lectins and combinations thereof, induce dose-dependent apoptosis in the ALL cell line NALM-6 via caspase-8 and -9 dependent pathways.


Subject(s)
Antineoplastic Agents, Phytogenic/administration & dosage , Phytotherapy , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Triterpenes/administration & dosage , Viscum album/chemistry , Animals , Antineoplastic Agents, Phytogenic/isolation & purification , Apoptosis/drug effects , Caspase 3/metabolism , Caspase 8/metabolism , Caspase 9/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Cytochromes c/metabolism , Drug Synergism , Female , Humans , Membrane Potential, Mitochondrial/drug effects , Mice , Mice, SCID , Oleanolic Acid/administration & dosage , Plant Extracts/administration & dosage , Plant Extracts/isolation & purification , Plant Lectins/administration & dosage , Plant Lectins/isolation & purification , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology , Solubility , Triterpenes/isolation & purification , Xenograft Model Antitumor Assays
12.
J Chem Phys ; 135(21): 214701, 2011 Dec 07.
Article in English | MEDLINE | ID: mdl-22149805

ABSTRACT

The physisorption of molecular hydrogen in model carbon foams has been investigated from 50 K to room temperature. The study is carried out within the framework of the density functional theory for quantum liquids at finite temperatures. Calculations are performed in the grand canonical ensemble, i.e., the adsorbed fluid is assumed to be in equilibrium with an external gas of hydrogen molecules with concentrations ranging from 8×10(-4) kg m(-3) to n=71 kg m(-3). It is shown that, while strong zero-point energy effects are present even at room temperature, the adsorption isotherms exhibit only a weak dependence on the explicit incorporation of the bosonic exchange symmetry of hydrogen molecules. The increase of the average particle density prevents the deviations from the Maxwell-Boltzmann statistics to become noticeable if the system is cooled down. The volumetric storage capacity of these materials at low temperatures is about one half of the U. S. Department of Energy goal, while the gravimetric capacity is still far from the standards required by mobile applications. The relation between the microscopic structure of the hydrogen fluid and the calculated adsorption properties is also addressed.

13.
Klin Padiatr ; 223(6): 364-7, 2011 Nov.
Article in English | MEDLINE | ID: mdl-22052633

ABSTRACT

A 12-year old girl presented with general weakness and weight loss, a localised cervical lymph node enlargement and cutaneous lesions compatible with lymphomatoid papulosis (LyP). Biopsies from lymph node and skin revealed a histological diagnosis of nodal large cell ALK-1- anaplastic lymphoma (ALCL) with a synchronous CD30+ cutaneous lymphoproliferation consistent with lymphomatoid papulosis (LyP). The girl was treated with mistletoe (MT) as monotherapy. Within 1 week after initiation of MT-treatment the skin lesions and lymph node enlargement improved. Under continuing MT-therapy 30 months after diagnosis the patient is still in complete remission. It is not possible to know whether this was a rare case of spontaneous remission of the nodal and skin-manifestations of this CD30+ T-cell lymphoproliferation or whether the observed effect was a specific therapeutic response to MT-treatment.


Subject(s)
Activin Receptors, Type II/analysis , Lymphoma, Large-Cell, Anaplastic/drug therapy , Lymphomatoid Papulosis/drug therapy , Mistletoe , Phytotherapy , Plant Extracts/therapeutic use , Remission Induction , Skin Neoplasms/drug therapy , Child , Female , Follow-Up Studies , Humans , Lymph Nodes/pathology , Lymphoma, Large-Cell, Anaplastic/diagnosis , Skin Neoplasms/diagnosis
14.
Surg Endosc ; 25(7): 2363, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21416187

ABSTRACT

BACKGROUND: A 23-year-old woman who 2 weeks before visiting our institution swallowed a plastic fork while attempting to induce vomiting during a party presented with progressive abdominal pain. Various techniques for removing foreign bodies from the intestinal tract have been described. We present the laparoscopic retrieval of a 15-cm fork from the duodenal bulb. METHODS: The patient presented with leukocytosis and epigastric tenderness. An upper endoscopy revealed a plastic fork, tines up, perforating the duodenal bulb. The handle was irremovably lodged in the opposite part of the duodenum. Perforating objects and objects larger than 7 cm ought to be removed surgically to prevent esophageal perforation. The patient was placed in supine position with the surgeon standing between her legs. Four trocars, two 10-mm and two 5-mm, were used. We saw a slight swelling of the duodenum with few fibrin stripes and roughly 250 ml of white exudate. The fork tines were visible; there were no injuries to the liver. The tines were held with a clamp while the perforated intestinal wall was carefully dissected with a monopolar hug and later with an ACE harmonic scalpel due to bleeding. The fork was extracted in the proximal direction through the perforation injury. There was no severe necrosis and debridement was not necessary. The bowel was irrigated and continuously sutured with 3-0 PDS. Finally, the fork was retrieved through the 10-mm trocar incision. RESULTS: Operating time was 60 min and blood loss was roughly 100 ml. The patient's postoperative course was uneventful. One year after intervention, the patient is doing well. CONCLUSION: A fork may be swallowed, but usually does not spontaneously pass through the gastrointestinal tract. Early removal should be advised to avoid perforation and to minimize morbidity. Laparoscopic removal is a safe and feasible method of managing foreign bodies that are not removable endoscopically.


Subject(s)
Duodenum/surgery , Foreign Bodies/surgery , Intestinal Perforation/surgery , Laparoscopy/methods , Cooking and Eating Utensils , Duodenum/injuries , Female , Humans , Young Adult
15.
Neuroscience ; 178: 21-32, 2011 Mar 31.
Article in English | MEDLINE | ID: mdl-21256195

ABSTRACT

Mice deficient in the water channel aquaporin-4 (AQP4) demonstrate increased seizure duration in response to hippocampal stimulation as well as impaired extracellular K+ clearance. However, the expression of AQP4 in the hippocampus is not well described. In this study, we investigated (i) the developmental, laminar and cell-type specificity of AQP4 expression in the hippocampus; (ii) the effect of Kir4.1 deletion on AQP4 expression; and (iii) performed Western blot and RT-PCR analyses. AQP4 immunohistochemistry on coronal sections from wild-type (WT) or Kir4.1-/- mice revealed a developmentally-regulated and laminar-specific pattern, with highest expression in the CA1 stratum lacunosum-moleculare (SLM) and the molecular layer (ML) of the dentate gyrus (DG). AQP4 was colocalized with the glial markers glial fibrillary acidic protein (GFAP) and S100ß in the hippocampus, and was also ubiquitously expressed on astrocytic endfeet around blood vessels. No difference in AQP4 immunoreactivity was observed in Kir4.1-/- mice. Electrophysiological and postrecording RT-PCR analyses of individual cells revealed that AQP4 and Kir4.1 were co-expressed in nearly all CA1 astrocytes. In NG2 cells, AQP4 was also expressed at the transcript level. This study is the first to examine subregional AQP4 expression during development of the hippocampus. The strikingly high expression of AQP4 in the CA1 SLM and DG ML identifies these regions as potential sites of astrocytic K+ and H2O regulation. These results begin to delineate the functional capabilities of hippocampal subregions and cell types for K+ and H2O homeostasis, which is critical to excitability and serves as a potential target for modulation in diverse diseases.


Subject(s)
Aquaporin 4/biosynthesis , Gene Expression Regulation, Developmental/genetics , Hippocampus/growth & development , Animals , Aquaporin 4/genetics , Astrocytes/metabolism , Astrocytes/physiology , Gene Expression Regulation, Developmental/physiology , Glial Fibrillary Acidic Protein/genetics , Glial Fibrillary Acidic Protein/metabolism , Hippocampus/metabolism , Hippocampus/physiology , Male , Membrane Potentials/physiology , Mice , Mice, Knockout , Mice, Transgenic , Nerve Growth Factors/metabolism , Neurons/metabolism , Neurons/physiology , Patch-Clamp Techniques , Potassium Channels, Inwardly Rectifying/genetics , Reverse Transcriptase Polymerase Chain Reaction/methods , S100 Calcium Binding Protein beta Subunit , S100 Proteins/metabolism
17.
Opt Lett ; 35(10): 1671-3, 2010 May 15.
Article in English | MEDLINE | ID: mdl-20479845

ABSTRACT

By irradiating spherical metal nanoparticles embedded in glass with several hundred ultrashort laser pulses at peak intensities of 0.2-1.5 TWcm(2), dichroic microstructures can be written in these nanocomposite materials. The underlying mechanism is transformation of the nanoparticles to prolate shapes. Using a single wavelength, the maximum aspect ratio achievable with this process is limited by partial destruction of particles. Here we show that this limitation can be overcome by simultaneous irradiation with different wavelengths. In particular, adding a relatively weak intensity at 800 nm to the main irradiation at 532 nm increases the maximum aspect ratio of Ag nanoparticles and the resulting separation between polarized surface plasmon bands dramatically. These effects are explained by the efficiency of electric field enhancement in the vicinity of nanoparticles, which influences the directed photoionization needed for particle shape transformation.

18.
Opt Express ; 18(4): 3700-7, 2010 Feb 15.
Article in English | MEDLINE | ID: mdl-20389380

ABSTRACT

We have investigated the nonlinear refractive index of ex-vivo pig cornea by a combined approach using the standard z-scan technique on extracted corneas or corneal slices, as well as studying the deviations caused by self-focusing during femtosecond laser processing of the pig eyes. The experiments yield consistently an upper limit of 1.2 MW for the critical power of self-focusing in porcine cornea, and a value of 2 x 10(-19) m(2)/W for its nonlinear refractive index. We also demonstrate that due to this nonlinear refraction the cutting depth of typical fs-laser surgery processing in cornea may depend considerably, albeit in a well controllable way, on the laser parameters.


Subject(s)
Cornea/physiology , Cornea/surgery , Laser Therapy/methods , Models, Biological , Refractometry/methods , Animals , Computer Simulation , Nonlinear Dynamics , Swine
19.
Phys Rev Lett ; 104(6): 065502, 2010 Feb 12.
Article in English | MEDLINE | ID: mdl-20366829

ABSTRACT

Objective molecular dynamics combined with density-functional-based tight binding makes it possible to compute chiral nanotubes as axial-screw dislocations. This enables the surprising revelation of a large catalog of MoS2 nanotubes that lack the prescribed translational symmetry and exhibit chirality-dependent electronic band gaps and elastic constants. Helical symmetry is the natural property to rely on when studying quasi-one-dimensional nanomaterials formally derived or grown via screw dislocations.

20.
Ultramicroscopy ; 110(1): 26-32, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19818559

ABSTRACT

This article analyzes electron energy-loss near-edge fine structures of the SrO(SrTiO(3))(n=1) Ruddlesden-Popper system and of the parent compounds SrTiO(3) and SrO by comparison with first principles calculations. For that, the fine structures of chemical solution deposited Ruddlesden-Popper films have been experimentally recorded by means of transmission electron microscopy. Moreover, density of states computations using an all-electron density-functional code have been performed. It is shown that the appearance and shape of the experimental O-K and Ti-L(2,3) fine structure features result from the crystallography-dependent electronic structure of the investigated oxides, which display technologically interesting dielectric as well as lattice-structural properties.

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