80,658 research outputs found
On-chip inverted emulsion method for fast giant vesicle production, handling, and analysis
Liposomes and giant unilamellar vesicles (GUVs) in particular are excellent compartments for constructing artificial cells. Traditionally, their use requires bench-top vesicle growth, followed by experimentation under a microscope. Such steps are time-consuming and can lead to loss of vesicles when they are transferred to an observation chamber. To overcome these issues, we present an integrated microfluidic chip which combines GUV formation, trapping, and multiple separate experiments in the same device. First, we optimized the buffer conditions to maximize both the yield and the subsequent trapping of the vesicles in micro-posts. Captured GUVs were monodisperse with specific size of 18 ± 4 µm in diameter. Next, we introduce a two-layer design with integrated valves which allows fast solution exchange in less than 20 s and on separate sub-populations of the trapped vesicles. We demonstrate that multiple experiments can be performed in a single chip with both membrane transport and permeabilization assays. In conclusion, we have developed a versatile all-in-one microfluidic chip with capabilities to produce and perform multiple experiments on a single batch of vesicles using low sample volumes. We expect this device will be highly advantageous for bottom-up synthetic biology where rapid encapsulation and visualization is required for enzymatic reactions
The Capital Structure Decisions of New Firms
Based on data from the Kauffman Firm Survey, examines the funding sources of firms in their first year of operations. Highlights start-ups' reliance on external debt financing such as bank loans and credit cards, regardless of their credit scores
Degeneracies when T=0 Two Body Interacting Matrix Elements are Set Equal to Zero : Talmi's method of calculating coefficients of fractional parentage to states forbidden by the Pauli principle
In a previous work we studied the effects of setting all two body T=0 matrix
elements to zero in shell model calculations for Ti (Sc) and
Ti. The results for Ti were surprisingly good despite the
severity of this approximation. In this approximation degeneracies arose in the
T=1/2 I= and states in Sc and the T=1/2
, , and in Sc. The T=0
, , , and states in Ti were degenerate as
well. The degeneracies can be explained by certain 6j symbols and 9j symbols
either vanishing or being equal as indeed they are. Previously we used Regge
symmetries of 6j symbols to explain these degeneracies. In this work a simpler
more physical method is used. This is Talmi's method of calculating
coefficients of fractional parentage for identical particles to states which
are forbidden by the Pauli principle. This is done for both one particle cfp to
handle 6j symbols and two particle cfp to handle 9j symbols. The states can be
classified by the dual quantum numbers ()
Aerodynamic Characteristics at a Mach Number of 6.8 of Two Hypersonic Missile Configurations, One with Low-Aspect-Ratio Cruciform Fins and Trailing-Edge Flaps and One with a Flared Afterbody and All-Movable Controls
An investigation has been made to determine the aerodynamic characteristics in pitch at a Mach number of 6.8 of hypersonic missile configurations with cruciform trailing-edge flaps and with all-movable control surfaces. The flaps were tested on a configuration having low-aspect-ratio cruciform fins with an apex angle of 5 degrees; the all-movable controls were mounted at the 46.7-percent body station on a configuration having a 10 degrees flared afterbody. The tests were made through an angle-of-attack range of -2 degrees to 20 degrees at zero sideslip in the Langley 11-inch hypersonic tunnel. The results indicated that the all-movable controls on the flared-afterbody model should be capable of producing much larger values of trim lift and of normal acceleration than the trailing-edge-flap configuration. The flared-afterbody configuration had considerably higher drag than the cruciform-fin model but only slightly lower values of lift-drag ratio
The milliped genus Euryurus Koch, 1847 (Polydesmida: Euryuridae) west of the Mississippi River; occurrence of E. leachii (Gray, 1832) on Crowley’s Ridge, Arkansas
The milliped genus Euryurus Koch, 1847, and the species, E. leachii (Gray, 1832) (Polydesmida: Euryuridae), are recorded from three sites on the northern part of Crowley’s Ridge (Cross, Lee, and Poinsett counties), Arkansas, where the only prior familial records are of Auturus evides (Bollman, 1887). Coupled with the published locality of E. leachii in Phillips Co., at the southern extremity of the Ridge, the only known occurrences of both the genus and species in Arkansas and west of the Mississippi River are in this physiographic feature. The Arkansas population is geographically peripheral but anatomically intermediate between the two recognized subspecies, E. l. leachii and E. l. fraternus Hoffman, 1978, and we do not assign it to a race. Molecular investigations seem necessary to resolve relationships in the “E. leachii complex.
Tackling disinvestment in health care services
Rising levels of demand due to ageing populations and increases in long term conditions (White 2007), increased levels of expectation amongst patients and inflationary pressure caused by the rising cost of new technologies are amongst the explanations for the funding shortfalls in government funded health systems across the world (Newhouse 1992). The challenge facing these health systems has also been intensified by the worldwide economic downturn. Within health systems, efforts have been made to increase productivity and efficiency and to control costs without reducing quality (Garner and Littlejohns 2011) but the scale of the task necessitates further action (Donaldson et al. 2010). Beyond productivity and efficiency gains the next logical step for decision makers is disinvestment in cost-ineffective services, prioritisation of funding for one service over another or what Prasad (2012) refers to as ‘medical reversal’. The aims of this study were to explore the experiences of budget holders within the English National Health Service (NHS) in their attempts to implement programmes of disinvestment, and to consider factors which influence the success (or otherwise) of this activity. This paper begins with clarification of terminology and a summary of the current state of knowledge with regard to health service disinvestment, before presenting and discussing findings. The research suggests that disinvestment activity is varied across organisations and ranges from ‘invest to save’ schemes through to ‘true disinvestment.’ Although the majority of interviewees accept that disinvestment is necessary most had made little progress at the time of interview beyond ‘picking the low hanging fruit’. Interviewees identify a number of determinants of disinvestment such as: local/national relationships, co-ordination/ collaboration and; professional understanding and support
Kinematics of the Broad Line Region in M81
A new model is presented which explains the origin of the broad emission
lines observed in the LINER/Seyfert nucleus of M81 in terms of a steady state
spherically symmetric inflow, amounting to 1 x 10^-5 Msun/yr, which is
sufficient to explain the luminosity of the AGN. The emitting volume has an
outer radius of ~1 pc, making it the largest broad line region yet to be
measured, and it contains a total mass of ~ 5 x 10^-2 Msun of dense, ~ 10^8
cm^-3, ionized gas, leading to a very low filling factor of ~ 5 x 10^-9. The
fact that the BLR in M81 is so large may explain why the AGN is unable to
sustain the ionization seen there. Thus, the AGN in M81 is not simply a scaled
down quasar.Comment: Accepted for Publication in ApJ 7/21/0
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