558 research outputs found
Prosthetic strap system for simplified ventral hernia repair. Its results in a porcine experimental model.
Abstract: Introduction
Aiming to achieve a simplified ventral hernia repair, a proprietary shaped mesh was experimentally
tested in the porcine model. The mesh is structured with a large central body and radiating straps. The
friction of the straps passing through the tissues are hypothesized to be adequate to maintain the mesh
in place during tissue ingrowth, avoiding classic point fixation while ensuring a wide coverage of the
abdomen.
Methods
The mesh, having 6 radial straps, was placed using a sublay preperitoneal technique in 4 pigs. All
straps were passed laterally through the abdominal wall and exteriorized from the skin. The straps
were trimmed at the level of the skin, allowing the stumps to recoil into the subcutaneous space. The
animal were euthanized at 1 and 4 months to determine the integration of the straps.
Results
Macroscopically all 24 straps were firmly incorporated within the abdominal wall. The tension free
placement of the mesh by using the straps was effective. The friction of the straps passing through the
tissues was adequate to keep the mesh well orientated. No dislocation of the implants was observed.
The strap system also allowed a broader coverage of the abdominal wall, far beyond the wound
opening.
Conclusions
The described arm system of the described implant seems to be effective in eliminating point fixation
of the mesh. The fixation arms seemed to have ensured the mesh stayed orientated in all animals. A
very wide lateral mesh placement was accomplished, assuring sufficient defect overlap when
shrinkage occurs
AGN feedback at z~2 and the mutual evolution of active and inactive galaxies
The relationships between galaxies of intermediate stellar mass and moderate
luminosity active galactic nuclei (AGNs) at 1<z<3 are investigated with the
Galaxy Mass Assembly ultra-deep Spectroscopic Survey (GMASS) sample
complemented with public data in the GOODS-South field. Using X-ray data,
hidden AGNs are identified in unsuspected star-forming galaxies with no
apparent signs of non-stellar activity. In the color-mass plane, two parallel
trends emerge during the ~2 Gyr between the average redshifts z~2.2 and z~1.3:
while the red sequence becomes significantly more populated by ellipticals, the
majority of AGNs with L(2-10 keV)>10^42.3 erg s^-1 disappear from the blue
cloud/green valley where they were hosted predominantly by star-forming systems
with disk and irregular morphologies. These results are even clearer when the
rest-frame colors are corrected for dust reddening. At z~2.2, the ultraviolet
spectra of active galaxies (including two Type 1 AGNs) show possible gas
outflows with velocities up to about -500 km s^-1 that are not observed neither
in inactive systems at the same redshift, nor at lower redshifts. Such outflows
indicate the presence of gas that can move faster than the escape velocities of
active galaxies. These results suggest that feedback from moderately luminous
AGNs (logL_X~2 by contributing to
outflows capable of ejecting part of the interstellar medium and leading to a
rapid decrease in the star formation in host galaxies with stellar masses
10<logM<11 M_Sun.Comment: Astrophysical Journal Letters, in press (6 pages, 4 figures
Pancreatic islets from non-heart beating donor pig: Two-layer preservation method in an in vitro porcine model
Purpose: Pancreata from non-heart beating donors could represent an unlimited source of islets if their cell viability can be efficiently preserved during the time necessary to process the organs by the use of a better solution of preservation compared to the classic University of Wisconsin solution. The aim of this study was to determine whether it is possible to obtain functioning "alive islets" from non-heart-beating donors by comparing, on a porcine model, the classic "UW ice-store" method with a two-layer cold storage method (TLM) using oxygenated Perfluorocarbons (PFC) and UW.Methods: Whole pancreata were harvested from 20 NHBDs female pigs with similar characteristics and preserved for 4 h in UW solution (n=10) or TLM (UW/PFC) solution (n=10). The isolated islets were then evaluated for number, viability, purity, and insulin secretion, also estimated after 8 weeks of cryopreservation.Results: The total number of islets obtained from isolation, and their function assayed by the insulin stimulation index, before and after cryopreservation, showed a higher value in the TLM group. No significative differences in terms of purity and viability before and after cryopreservation were found when comparing the two groups.Conclusions: TLM solution for NHBDs porcine pancreata with cold ischemia time lower than 4 h offers significant advantages over UW solution storage, thereby increasing the isolation yield and isolation success rate of the pancreatic porcine islet
The extended epoch of galaxy formation: age dating of ~3600 galaxies with 2<z<6.5 in the VIMOS Ultra-Deep Survey
We aim at improving constraints on the epoch of galaxy formation by measuring
the ages of 3597 galaxies with spectroscopic redshifts 2<z<6.5 in the VIMOS
Ultra Deep Survey (VUDS). We derive ages and other physical parameters from the
simultaneous fitting with the GOSSIP+ software of observed UV rest-frame
spectra and photometric data from the u-band up to 4.5 microns using composite
stellar population models. We conclude from extensive simulations that at z>2
the joint analysis of spectroscopy and photometry combined with restricted age
possibilities when taking into account the age of the Universe substantially
reduces systematic uncertainties and degeneracies in the age derivation. We
find galaxy ages ranging from very young with a few tens of million years to
substantially evolved with ages up to ~1.5-2 Gyr. The formation redshifts z_f
derived from the measured ages indicate that galaxies may have started forming
stars as early as z_f~15. We produce the formation redshift function (FzF), the
number of galaxies per unit volume formed at a redshift z_f, and compare the
FzF in increasing redshift bins finding a remarkably constant 'universal' FzF.
The FzF is parametrized with (1+z)^\zeta, with \zeta~0.58+/-0.06, indicating a
smooth 2 dex increase from z~15 to z~2. Remarkably this observed increase is of
the same order as the observed rise in the star formation rate density (SFRD).
The ratio of the SFRD with the FzF gives an average SFR per galaxy of
~7-17Msun/yr at z~4-6, in agreement with the measured SFR for galaxies at these
redshifts. From the smooth rise in the FzF we infer that the period of galaxy
formation extends from the highest possible redshifts that we can probe at z~15
down to redshifts z~2. This indicates that galaxy formation is a continuous
process over cosmic time, with a higher number of galaxies forming at the peak
in SFRD at z~2 than at earlier epochs. (Abridged)Comment: Submitted to A&A, 24 page
Laparotomic vs laparoscopic ovariectomy: comparing the two methods. The ovariectomy in the bitch in laparoscopic era
BACKGROUND: The aim of the present work is to evaluate the effectiveness of the use of ultrasound scalpel during laparoscopic ovariectomy in the bitch.
METHODS: Two groups of 10 subjects each, of different races and ages, were compared. In the first group, ovariectomy was performed laparoscopically, using harmonic scalpel to remove ovary. In the second group surgery was performed by means of classical laparotomy.
RESULTS: Pre-operative time was similar in both groups. Total operative time, from incision to skin suture, showed significant difference between the two groups, being laparoscopy faster than laparotomy. Partial operative time for bilateral oophorectomy resulted lower using open technique, but, considering each ovary, there was no significant difference in both groups.
CONCLUSIONS: The use of harmonic scalpel to perform ovariectomy during laparoscopy is an effective time-sparing surgical approach compared to the already great practicality of laparotomy
The Cosmic Evolution Survey (COSMOS): a large-scale structure at z=0.73 and the relation of galaxy morphologies to local environment
We have identified a large-scale structure at z~0.73 in the COSMOS field,
coherently described by the distribution of galaxy photometric redshifts, an
ACS weak-lensing convergence map and the distribution of extended X-ray sources
in a mosaic of XMM observations. The main peak seen in these maps corresponds
to a rich cluster with Tx= 3.51+0.60/-0.46 keV and Lx=(1.56+/-0.04) x 10^{44}
erg/s ([0.1-2.4] keV band). We estimate an X-ray mass within
corresponding to M500~1.6 x 10^{14} Msun and a total lensing mass (extrapolated
by fitting a NFW profile) M(NFW)=(6+/-3) x 10^15 Msun. We use an automated
morphological classification of all galaxies brighter than I_AB=24 over the
structure area to measure the fraction of early-type objects as a function of
local projected density Sigma_10, based on photometric redshifts derived from
ground-based deep multi-band photometry. We recover a robust morphology-density
relation at this redshift, indicating, for comparable local densities, a
smaller fraction of early-type galaxies than today. Interestingly, this
difference is less strong at the highest densities and becomes more severe in
intermediate environments. We also find, however, local "inversions'' of the
observed global relation, possibly driven by the large-scale environment. In
particular, we find direct correspondence of a large concentration of disk
galaxies to (the colder side of) a possible shock region detected in the X-ray
temperature map and surface brightness distribution of the dominant cluster. We
interpret this as potential evidence of shock-induced star formation in
existing galaxy disks, during the ongoing merger between two sub-clusters.Comment: 15 pages (emulateapj style), 16 figs (low res.); to appear in the ApJ
Supplement COSMOS Special Issue. Low-resolution figures; full resolution
version available at:
http://www.astro.caltech.edu/~cosmos/publications/files/guzzo_0701482.pd
Histologic effects of university of wisconsin two-layer method preservation of rat pancreas.
Marginal donors represent a poorly utilized source of organs for transplantation despite their availability. The key is to reduce the ischemic damage in the effort to improve organ quality. This study investigated the histologic effects after in situ perfusion of preservation with a two-layer method compared with the classic University of Wisconsin preservation in term of tissue integrity and number of viable exocrine cells in the rat pancreas both after exsanguination and at 8 weeks of cryopreservation. Pancreata harvested from 60 rats were collected using 3 methods: two-layer method following University of Wisconsin perfusion; exsanguination; and classic University of Wisconsin perfusion/storage. In addition to histologic analysis of collected pancreata, we analyzed the number of CK19(+) cells and their viability using chi-square tests with values P < .05 considered to be significant. Rat pancreas histology showed as University of Wisconsin in situ perfusion and preservation by the two-layer method to be more effective to maintain the morphologic integrity of both exocrine and endocrine tissues. There were a larger number of CK19(+) cells with good viability. Moreover, the effects of oxygenation were visible in pancreas biopsies preserved after exsanguination. In situ University of Wisconsin perfusion and preservation for 240 minutes with the two-layer method yielded greater numbers and viability of CK19(+) cells even after 8 weeks of cryopreservation
Tracking the transfer of antimicrobial resistance genes from raw materials to sourdough breads
The present study hypothesizes that raw materials used in bread making can transfer antibiotic resistance genes (ARGs) to processed breads. Four types of flour and four types of semolina were purchased from supermarkets and inoculated with a commercial dried sourdough starter to make breads. The microbiological characteristics of all raw materials and fermented doughs were investigated. The levels of yeasts and lactic acid bacteria (LAB) increased up to 107 CFU/g. The values of pH decreased to 4.54â4.86 while total titratable acidity increased inversely. All unprocessed and processed samples, including breads, were analyzed by a molecular approach to detect bacterial and fungal DNAs and 17 antibiotic resistance genes for penicillins, macrolides, tetracyclines, and chloramphenicol. Illumina technology showed that the operational taxonomy units (OTUs) identified from unprocessed wheat milling products, fermented doughs, and baked products mainly belonged to Acetobacteraceae. Enterococci were present in all doughs. After baking, the relative abundance (RA)% of Enterococcus and Acetobacteraceae decreased. The DNA analyzed for fungal composition showed that Kazachstania humilis dominated dried sourdough starter and doughs, and its OTUs were also detected at high RA% in baked products. The search for ARGs revealed that all samples analyzed did not show resistance to penicillins, chloramphenicol, and macrolides. However, three of the semolinas included in this study (S1, S3 and S4) and the corresponding doughs (SD1, SD3 and SD4) were positive for tet(A) and tet(B) resistance genes. This work indicated that breads have a limited role in the dissemination of ARG
Vacuum inversion and securing of distal colonic pseudodiverticula with novel spiked O-rings
Diverticular disease is increasingly prevalent in Western societies and is associated with significant morbidity.
OBJECTIVE:
Two-stage endoscopic device development for inversion and secured ligation of colonic diverticula; first, human cadaver studies were performed to measure forces required for diverticular inversion; second, a novel set of devices (elastic spiked O-ring with delivery system) was tested in animals.
DESIGN:
Prospective, observational study of human cadavers and prospective, interventional study of a porcine model.
SETTING:
University hospital pathology laboratory and animal facility.
INTERVENTION:
Full-thickness inversion of the colonic wall with a pipelike delivery instrument to produce an inverted pseudodiverticulum that was secured with a spiked O-ring.
MAIN OUTCOME MEASUREMENTS:
The forces required for diverticular inversion, the secured closure of inverted pseudodiverticula, and the time until necrotic tissue falls off.
RESULTS:
A total of 248 of 248 of cadaveric sigmoid diverticula could be inverted by means of vacuum or forceps. The forces required for inversion ranged from 0.28 to 0.47 N (median, 0.37 N). Twenty-four spiked O-rings were delivered in 6 living pigs to produce 24 inverted pseudodiverticula. One animal died the day after the procedure of a pulmonary thromboembolism. In the remaining 5 pigs, all delivered spiked O-rings remained in place for 7 to 22 days. At necropsy, none of the inverted sites showed signs of perforation but rather full-thickness reparative scarring with ingrowth of connective tissue.
LIMITATIONS:
Animal model, stiff pipelike delivery instrument, variations in diverticular location, diameter, and size.
CONCLUSIONS:
Endoluminal inversion and securing of colonic diverticula induces tissue necrosis, diverticular sloughing, and full-thickness scarring
- âŠ