Simple Modifications of Branched PEI Lead to Highly Efficient siRNA Carriers with Low Toxicity

Polymer carriers like PEI which proved their efficiency in DNA delivery were found to be far less effective for the applications with siRNA. In the current study, we generated a number of nontoxic derivates of branched PEI through modification of amines by ethyl acrylate, acetylation of primary amines, or introduction of negatively charged propionic acid or succinic acid groups to the polymer structure. The resulting products showed high efficiency in siRNA-mediated knockdown of target gene. In particular, succinylation of branched PEI resulted in up to 10-fold lower polymer toxicity in comparison to unmodified PEI. Formulations of siRNA with succinylated PEI were able to induce remarkable knockdown (80% relative to untreated cells) of target luciferase gene at the lowest tested siRNA concentration of 50 nM in Neuro2ALuc cells. The polyplex stability assay revealed that the efficiency of formulations which are stable in physiological saline is independent of the affinity of siRNA to the polymer chain. The improved properties of modified PEI as siRNA carrier are largely a consequence of the lower polymer toxicity. In order to achieve significant knockdown of target gene, the PEI-based polymer has to be applied at higher concentrations, required most probably for sufficient accumulation and proton sponge effects in endosomes. Unmodified PEI is highly toxic at such polymer concentrations. In contrast, the far less toxic modified analogues can be applied in concentrations required for the knockdown of target genes without side effects

CP Violation in B → ψX and B → DD: A Small Step for a Penguin

The standard model of particle physics is experimentally confirmed to a very high precision, this requires as well an improvement of theoretical precision. We use an operator product expansion to predict CP asymmetries in the exclusive decays B → ψX and B → DD. These lead to the most precise theoretical determination of the angle β (βs) in the Bd (Bs) unitarity triangle

The Swiss National Bank's monetary policy concept - an example of a 'principles-based' policy framework

The practice of monetary policy has evolved a great deal since the early 1990s. This evolution was significantly influenced by rapid developments in the theory of monetary policy. A new consensus about 'principles-based' monetary policy appears to be emerging. It marries a firm long-term anchor for nominal stability, rooted in the original ideas behind inflation targeting, with short-term flexibility, based on a more discretionary and pragmatic approach to monetary policy. The SNB's monetary policy framework - with a firm nominal anchor but with an emphasis on the need for flexibility - reflects, to a considerable degree, the emerging academic consensus about best-practice monetary policy. With its successful seven-year track record, it may serve as an interesting case study for a policy aiming at an intermediate position between full discretion and rigidly defined short-term inflation targeting.Swiss National Bank, monetary policy, inflation targeting, rules, discretion

Breathing Life into Polycations

The lack of efficient delivery systems is still limiting the full therapeutic potential of siRNA. For the purpose of nucleic acid transfer, among other synthetic carrier systems, polycations have been applied. Favorable characteristics of suitable polymers include nucleic acid binding, compaction, protection, and biocompatibility. However the lack of nucleic acid transfer activity in transfection-based screening often abandons promising candidates. Here we present that functionalization may turn polycations with poor delivery activity into efficient carriers:  for example, polylysine, on its own lacking nucleic acid transfer activity, displayed high efficiency in siRNA delivery after modification with polyethylene glycol and a pH-responsive endosomolytic peptide. Hence these findings have implication for the selection process of polymeric carriers for siRNA

DNA as Tunable Adaptor for siRNA Polyplex Stabilization and Functionalization

siRNA and microRNA are promising therapeutic agents, which are engaged in a natural mechanism called RNA interference that modulates gene expression posttranscriptionally. For intracellular delivery of such nucleic acid triggers, we use sequence-defined cationic polymers manufactured through solid phase chemistry. They consist of an oligoethanamino amide core for siRNA complexation and optional domains for nanoparticle shielding and cell targeting. Due to the small size of siRNA, electrostatic complexes with polycations are less stable, and consequently intracellular delivery is less efficient. Here we use DNA oligomers as adaptors to increase size and charge of cargo siRNA, resulting in increased polyplex stability, which in turn boosts transfection efficiency. Extending a single siRNA with a 181-nucleotide DNA adaptor is sufficient to provide maximum gene silencing aided by cationic polymers. Interestingly, this simple strategy was far more effective than merging defined numbers (4-10) of siRNA units into one DNA scaffolded construct. For DNA attachment, the 3' end of the siRNA passenger strand was beneficial over the 5' end. The impact of the attachment site however was resolved by introducing bioreducible disulfides at the connection point. We also show that DNA adaptors provide the opportunity to readily link additional functional domains to siRNA. Exemplified by the covalent conjugation of the endosomolytic influenza peptide INF-7 to siRNA via a DNA backbone strand and complexing this construct with a targeting polymer, we could form a highly functional polyethylene glycol-shielded polyplex to downregulate a luciferase gene in folate receptor-positive cells

Rightful Resistance in the Colombian conflict. A theoretical reflection based on a Peace Community

Este artículo reflexiona sobre las opciones por parte de civiles de resistir pacíficamente en conflictos armados. Los argumentos desarrollados aquí se basan en una investigación de campo en la Comunidad de Paz de San José de Apartadó, Colombia. El marco analítico y teórico por medio del cual se delimita en este artículo la aplicación del término ‘resistencia’, se basa en las consideraciones conceptuales de Hollander y Einwohner (2004) y en el concepto teórico de ‘resistencia legítima’ de O’Brien (1996). Después de un breve análisis del conflicto, describiremos los procesos socio-históricos de la zona de Apartadó, y las experiencias auto-organizativas de sus habitantes, las cuales favorecieron la conformación de esta iniciativa de paz. El análisis de las dimensiones y de los objetivos de la resistencia de la Comunidad de Paz permite reconceptualizar la idea de ‘resistencia legítima’ de O’Brien.This article considers the opportunities of civilians to peacefully resist violent conflicts or civil wars. The argument developed here is based on a field-based research on the peace community San José de Apartadó in Colombia. The analytical and theoretical framework, which delimits the use of the term ‘resistance’ in this article, builds on the conceptual considerations of Hollander and Einwohner (2004) and on the theoretical concept of ‘rightful resistance’ developed by O’Brien (1996). Beginning with a conflict-analytical classification of the case study, we will describe the long-term socio-historical processes and the organizational experiences of the civilian population, which favoured the emergence of this resistance initiative. The analytical approach to the dimensions and aims of the resistance of this peace community leads to the differentiation of O`Brian’s concept of ‘rightful resistance’

Stereologische Analyse von Mikroglia und afferenten Terminalen im Facialiskerngebiet nach facio-facialer Anastomose bei der Ratte und Korrelation polyinnervierter Endplatten mit der Vibrissenbewegung

Mit der Durchtrennung des Facialisnervs wird eine Vielzahl von Prozessen in Gang gesetzt, die der Nervenregeneration und Reinnervation der Muskulatur dienen. Die eigentliche Funktion der Motoneurone, die Generierung von Aktionspotentialen zur Ausbildung von Muskelkontraktionen, wird herunter reguliert. Solche reaktiven Prozesse sind zum einen die Deafferenzierung des Facialiskerngebiets, um ein schädigendes Übermaß exzitatorischen Inputs an den Motoneuronen zu vermeiden und zum anderen eine damit assoziierte Mikrogliose, welche, neben der initialen Aufrechterhaltung der Vitalität von Motoneuronen, die Fähigkeit besitzt über eine Neosynaptogenese die Reafferenzierung des Facialiskerngebiets zu modulieren. Bisher wurden diese Prozesse bis 2 Monate nach Durchtrennung des Facialisnervs und facio-facialer Anastomose (FFA) nachbeobachtet, wobei sich zusätzlich noch eine Atrophie des Facialiskerngebiets und eine vermehrte Abnahme exzitatorischer Terminale, im Vergleich zu den inhibitorischen Terminalen, zeigte. Um diese Reaktionen im Facialiskerngebiet im weiteren Verlauf zu untersuchen, wurden 16 Ratten in zwei Gruppen (jeweils N = 8) eingeteilt, von denen die eine Gruppe eine facio-faciale Anastomose (FFA) nach Transsektion des Facialisnervs erhielt und die andere Gruppe ohne Facialisläsion nur scheinoperiert wurde. Vier Monate nach dem operativen Eingriff wurde der Hirnstamm entnommen und immunhistochemisch gefärbte Schnitte hergestellt, sodass der Facialiskern anschließend stereologisch ausgewertet werden konnte. Mittels fluoreszierender Antikörper gegen den vesikulären Glutamat-Transporter-2 (VGLUT2) und den vesikulären GABA-Transporter (VGAT) wurden sowohl die exzitatorischen als auch die inhibitorischen afferenten Terminalen im Facialiskern analysiert. Große C-Typ-Terminale, die cholinerge Präsynapsen an Nissl-gefärbten Motoneuronen-Perikarya und proximalen Dendriten darstellen, wurden mittels Antikörper gegen Cholinacetyltransferase (ChAT) gefärbt und analysiert. Mikroglia wurde mittels Antikörper gegen ionisiertes-Calcium-bindendes-Adaptermolekül-1 (Iba1) dargestellt. Die Ergebnisse der Untersuchungen 4 Monate nach FFA zeigten, dass das Facialiskerngebiet in seinem Volumen um -19% atrophiert, aber keine Atrophie oder ein Verlust von Motoneuronen zu Verzeichnen war. Vielmehr waren die exzitatorischen (VGLUT2+) und inhibitorischen (VGAT+) afferenten Terminalen in ihrer Gesamtheit um -8% reduziert. Dies war auf einen starken Verlust VGLUT2+ Terminale zurückzuführen, da die Anzahl der VGAT+ Terminalen im Vergleich zu Kontrolltieren zugenommen hatte. Ebenfalls war eine signifikante Reduktion der ChAT+ axosomatischen Synapsendichte um -42% zu verzeichnen. Daraus resultiert eine verminderte Aktionspotentialbereitschaft und somit die reduzierte Modulation der frequentierten Rhythmik feuernder Motoneurone. Die Analyse der Mikroglia ergab, dass selbst 4 Monate nach FFA im Facialiskerngebiet noch eine Überzahl an Mikroglia im Vergleich zu Kontrolltieren vorlag. Dies kann als Ausdruck eines anhaltenden Prozesses der Reintegration afferenter Signale mit motoneuronalen Postsynapsen im Rahmen der Neosynaptogenese angesehen werden. Während der Aussprossung der sich regenerierenden Axone des Facialisnervs können sich durch Fehlleitungen verschiedene pathologische Veränderungen in den Muskelfasern ergeben, die einen starken negativen Einfluss auf die Muskelfunktion ausüben. Mehrere neuromuskuläre Endplatten können zum einen polyneuronal, also durch Axonterminale verschiedener Motoneurone, oder zum anderen seriell durch eine einzige ausgeprossene Axonterminale gleichzeitig innerviert werden. Um zu überprüfen, ob der Grad der polyinnervierten Muskelfasern mit der Schwere der funktionellen Beeinträchtigung zusammen hängt, wurde die Vibrissenbewegung der Ratten 4 Monate nach FFA gefilmt und anschließend der ipsilaterale M. levator labii superioris, als repräsentativer externer Vibrissenmuskel, entnommen. In seriellen Schnitten wurden die Axonterminalen zwischen den Muskelfasern mit fluoreszierenden Antikörpern gegen ChAT und die neuromuskulären Endplatten mit Fluorophor-konjugiertem α-Bungarotoxin angefärbt. Als Parameter der Vibrissenkinematik, die den Grad der funktionellen Reintegration der Muskulatur wiederspiegelt, wurde die maximale Amplitude der Vibrissenbewegungen verwendet. Vier Monate nach FFA wiesen 32% der neuromuskulären Endplatten eine Polyinnervation auf. Im Hinblick auf einen hypothetischen Zusammenhang zwischen dem Innervationszustand der Muskelfasern beider Gruppen und den funktionellen Parametern aus den Videoanalysen ergab sich eine starke negative Korrelation und somit eine Bestätigung des negativen Einflusses der Fehlinnervation auf das funktionelle Outcome nach Facialisregeneration

A Novel Distal Very Long Roux-en Y Gastric Bypass (DVLRYGB) as a Primary Bariatric Procedure—Complication Rates, Weight Loss, and Nutritional/Metabolic Changes in the First 355 Patients

Proximal Roux-en Y gastric bypass (RYGB) representing the most frequently performed bariatric procedure yields a weight loss failure rate of around 20%. In order to reduce failure rates, we established a novel distal RYGB variant characterized by a very long alimentary (Roux) limb and a short common channel. Up to 5years, follow-up data (complication rates, weight loss, nutritional/metabolic changes) of the first 355 patients (mean ± SD preoperative age, 41.4 ± 10.8years; BMI, 48.5 ± 11.5kg/m2) who underwent the novel Distal Very Long Roux-en Y Gastric Bypass (DVLRYGB) were analysed. Overall follow-up rate was 98.9%, mean follow-up time 1.6 ± 1.4years. Limb lengths were as follows: common channel 76 ± 7cm, biliopancreatic limb 79 ± 14cm, and alimentary (Roux) limb 604 ± 99cm. The operation was performed laparoscopically in 95.2% of the cases. Thirty-day mortality was zero; major and minor complication rate was 4.5% and 10.4%, respectively. Average excess weight loss (EWL) was >74% 3, 4, and 5years after the operation and failure rate defined by an EWL < 50% remained < 6%. Annually blood measurements revealed a relatively low incidence rate of severe nutritional deficiencies, but mild anaemia and hypoproteinemia were frequently observed. Laparoscopic revision with a proximalization of the lower anastomosis was required in 4 (1.1%) patients. Data indicate that our DVLRYGB leads to excellent weight loss results. Furthermore, within the setting of a structured multidisciplinary follow-up program, the incidence of severe malnutrition states was relatively lo

Analisia Pengaruh Campuran Bahan Bakar Solar-minyak Jarak Pagar Pada Kinerja Motor Diesel Dan Emisi Gas Buang

A test of a diesel motor using the fuel mixture of diesel-jatropha oil has been conducted in order to analyze the influence of fuel mixture composition to the motor performance and exhaust gas emission. The motor which had a single cylinder, 4 cycles, with maximum energy output of 4.4 kW at 2600 rpm, moved agenerator as electricity power load. The percentage of jatropha oil in fuel mixture was 0%, 10%, 30%, 50% and 100%. The testing method was, to each fuel mixture composition and at constant 2000 rpm motor rotation with electricity power load of 0 and 2 kW, the data concerning to the fuel consumption, lubricating oiltemperature and exhaust gas emission was measured. The test result indicated that the higher the percentage of jatropha oil in fuel mixture, the higher the fuel consumption and the CO2 and NOx emission in exhaust gas, but the lower the HC and O2 emission and opacity of exhaust gas

Immersed boundary parametrizations for full waveform inversion

Full Waveform Inversion (FWI) is a successful and well-established inverse method for reconstructing material models from measured wave signals. In the field of seismic exploration, FWI has proven particularly successful in the reconstruction of smoothly varying material deviations. In contrast, non-destructive testing (NDT) often requires the detection and specification of sharp defects in a specimen. If the contrast between materials is low, FWI can be successfully applied to these problems as well. However, so far the method is not fully suitable to image defects such as voids, which are characterized by a high contrast in the material parameters. In this paper, we introduce a dimensionless scaling function $\gamma$ to model voids in the forward and inverse scalar wave equation problem. Depending on which material parameters this function $\gamma$ scales, different modeling approaches are presented, leading to three formulations of mono-parameter FWI and one formulation of two-parameter FWI. The resulting problems are solved by first-order optimization, where the gradient is computed by an ajdoint state method. The corresponding Fr\'echet kernels are derived for each approach and the associated minimization is performed using an L-BFGS algorithm. A comparison between the different approaches shows that scaling the density with $\gamma$ is most promising for parameterizing voids in the forward and inverse problem. Finally, in order to consider arbitrary complex geometries known a priori, this approach is combined with an immersed boundary method, the finite cell method (FCM).Comment: 23 pages, 21 figure