3,852 research outputs found
Fracture healing following high energy tibial trauma: Ilizarov versus Taylor Spatial Frame
Introduction: The optimal treatment of high energy tibial fractures remains controversial and a challenging orthopaedic problem. The role of external fi xators for all these tibial fractures has been shown to be crucial. Methods: A fi ve-year consecutive series was reviewed retrospectively, identifying two treatment groups: Ilizarov and Taylor Spatial Frame (TSF; Smith & Nephew, Memphis, TN, US). Fracture healing time was the primary outcome measure. Results: A total of 112 patients (85 Ilizarov, 37 TSF) were identifi ed for the review with a mean age of 45 years. This was higher in women (57 years) than in men (41 years). There was no signifi cant difference between frame types (p=0.83). The median healing time was 163 days in both groups. There was no signifi cant difference in healing time between smokers and non-smokers (180 vs 165 days respectively, p=0.07), open or closed fractures (p=0.13) or age and healing time (Spearman's r=0.12, p=0.18). There was no incidence of non-union or re-fracture following frame removal in either group. Conclusions: Despite the assumption of the rigid construct of the TSF, the median time to union was similar to that of the Ilizarov frame and the TSF therefore can play a signifi cant role in complex tibial fractures
Sequential Palladium-Catalyzed Allylic Alkylation/retro-Dieckmann Fragmentation Strategy for the Synthesis of α-Substituted Acrylonitriles.
A straightforward synthesis of α-substituted acrylonitriles is described using 4-cyano-3-oxotetrahydro-thiophene (c-THT) as an acrylonitrile surrogate. This unprecedented two-step sequence featuring a palladium-catalyzed allylic alkylation (Pd-AA) and a retro-Dieckmann fragmentation provides a general entry into diversely substituted 1,4-dienes
Effects of boron fertilization on calcium:boron ratio and boron mobility in cauliflower
Greenhouse studies were conducted on two different alfisols, Bajaura (Loam) and Junga (Sandy loam), that are deficient in boron (B) for cauliflower (Brassica oleracea L. var. botrytis). The calcium:boron (Ca:B) ratio in cauliflower leaves with applied B (1 to 3 mg kg−1 soil) varied from 1276 to 521 in the Bajaura soil with high exchangeable-Ca and no deficiency or toxicity symptoms were evident. In the Junga soil with low exchangeable-Ca, however, the Ca:B ratio varied from 505 to 223 with toxicity symptoms visible when 2 and 3 mg kg−1 B has been applied. This corresponds to a Ca:B ratio of 256 and 223. Farm yard manure application showed an ameliorating effect on Ca:B ratio with a tendency to decrease a high Ca:B ratio in the absence of B application and increase a lower Ca:B ratio when incorporated with higher levels of B. The B mobility from leaves to curd decreased with increasing levels of B application and thus provided a circumstantial evidence for B retranslocation under conditions of low B supply i.e. conditional mobility
Influence of transport and ocean ice extent on biogenic aerosol sulfur in the Arctic atmosphere
The recent decline in sea ice cover in the Arctic Ocean could affect the regional radiative forcing via changes in sea ice-atmosphere exchange of dimethyl sulfide (DMS) and biogenic aerosols formed from its atmospheric oxidation, such as methanesulfonic acid (MSA). This study examines relationships between changes in total sea ice extent north of 70 degrees N and atmospheric MSA measurement at Alert, Nunavut, during 1980-2009; at Barrow, Alaska, during 1997-2008; and at Ny-Alesund, Svalbard, for 1991-2004. During the 1980-1989 and 1990-1997 periods, summer (July-August) and June MSA concentrations at Alert decreased. In general, MSA concentrations increased at all locations since 2000 with respect to 1990 values, specifically during June and summer at Alert and in summer at Barrow and Ny-Alesund. Our results show variability in MSA at all sites is related to changes in the source strengths of DMS, possibly linked to changes in sea ice extent as well as to changes in atmospheric transport patterns. Since 2000, a late spring increase in atmospheric MSA at the three sites coincides with the northward migration of the marginal ice edge zone where high DMS emissions from ocean to atmosphere have previously been reported. Significant negative correlations are found between sea ice extent and MSA concentrations at the three sites during the spring and June. These results suggest that a decrease in seasonal ice cover influencing other mechanisms of DMS production could lead to higher atmospheric MSA concentrations
The structure of superheavy elements newly discovered in the reaction of Kr with Pb
The structure of superheavy elements newly discovered in the
Pb(Kr,n) reaction at Berkeley is systematically studied in the
Relativistic Mean Field (RMF) approach. It is shown that various usually
employed RMF forces, which give fair description of normal stable nuclei, give
quite different predictions for superheavy elements. Among the effective forces
we tested, TM1 is found to be the good candidate to describe superheavy
elements. The binding energies of the 118 nucleus and its
decay daughter nuclei obtained using TM1 agree with those of FRDM
within 2 MeV. Similar conclusion that TM1 is the good interaction is also drawn
from the calculated binding energies for Pb isotopes with the Relativistic
Continuum Hartree Bogoliubov (RCHB) theory. Using the pairing gaps obtained
from RCHB, RMF calculations with pairing and deformation are carried out for
the structure of superheavy elements. The binding energy, shape, single
particle levels, and the Q values of the decay are
discussed, and it is shown that both pairing correlation and deformation are
essential to properly understand the structure of superheavy elements. A good
agreement is obtained with experimental data on . %Especially, the
atomic number %dependence of %seems to match with the experimental
observationComment: 19 pages, 5 figure
Pressure dependent electronic properties of MgO polymorphs: A first-principles study of Compton profiles and autocorrelation functions
The first-principles periodic linear combination of atomic orbitals method
within the framework of density functional theory implemented in the CRYSTAL06
code has been applied to explore effect of pressure on the Compton profiles and
autocorrelation functions of MgO. Calculations are performed for the B1, B2,
B3, B4, B8_1 and h-MgO polymorphs of MgO to compute lattice constants and bulk
moduli. The isothermal enthalpy calculations predict that B4 to B8_1, h-MgO to
B8_1, B3 to B2, B4 to B2 and h-MgO to B2 transitions take place at 2, 9, 37, 42
and 64 GPa respectively. The high pressure transitions B8_1 to B2 and B1 to B2
are found to occur at 340 and 410 GPa respectively. The pressure dependent
changes are observed largely in the valence electrons Compton profiles whereas
core profiles are almost independent of the pressure in all MgO polymorphs.
Increase in pressure results in broadening of the valence Compton profiles. The
principal maxima in the second derivative of Compton profiles shifts towards
high momentum side in all structures. Reorganization of momentum density in the
B1 to B2 structural phase transition is seen in the first and second
derivatives before and after the transition pressure. Features of the
autocorrelation functions shift towards lower r side with increment in
pressure.Comment: 19 pages, 8 figures, accepted for publication in Journal of Materials
Scienc
Reported outcomes in transsphenoidal surgery for pituitary adenomas: a systematic review
PURPOSE: Transsphenoidal surgery is an established treatment for pituitary adenomas. We examined outcomes and time points following transsphenoidal surgery for pituitary adenoma to identify reporting heterogeneity within the literature. METHODS: A systematic review of studies that reported outcomes for transsphenoidal surgery for pituitary adenoma 1990–2021 were examined. The protocol was registered a priori and adhered to the PRISMA statement. Studies in English with > 10 patients (prospective) or > 500 patients (retrospective) were included. RESULTS: 178 studies comprising 427,659 patients were included. 91 studies reported 2 or more adenoma pathologies within the same study; 53 studies reported a single pathology. The most common adenomas reported were growth hormone-secreting (n = 106), non-functioning (n = 101), and ACTH-secreting (n = 95); 27 studies did not state a pathology. Surgical complications were the most reported outcome (n = 116, 65%). Other domains included endocrine (n = 104, 58%), extent of resection (n = 81, 46%), ophthalmic (n = 66, 37%), recurrence (n = 49, 28%), quality of life (n = 25, 19%); and nasal (n = 18, 10%). Defined follow up time points were most reported for endocrine (n = 56, 31%), extent of resection (n = 39, 22%), and recurrence (n = 28, 17%). There was heterogeneity in the follow up reported for all outcomes at different time points: discharge (n = 9),  1 year (n = 69). CONCLUSION: Outcomes and follow up reported for transsphenoidal surgical resection of pituitary adenoma are heterogenous over the last 30 years. This study highlights the necessity to develop a robust, consensus-based, minimum, core outcome set. The next step is to develop a Delphi survey of essential outcomes, followed by a consensus meeting of interdisciplinary experts. Patient representatives should also be included. An agreed core outcome set will enable homogeneous reporting and meaningful research synthesis, ultimately improving patient care
Bisphosphonate-related osteonecrosis of jaw (BRONJ): diagnostic criteria and possible pathogenic mechanisms of an unexpected anti-angiogenic side effect.
Recently, bisphosphonates (BPs) have been widely used in medical practice as anti-resorptive agents owing to their anti-osteoclatic action. In addition, these compounds are also used for their analgesic action and their potential anti-tumour effect. Patients treated with BPs may subsequently develop osteonecrosis of the jaw or maxillary bone after minor local trauma including dental work, recently labelled as bisphosphonate osteonecrosis of jaw (BRONJ). However, the etiopathogenic mechanisms of this pathological condition are poorly understood. Although, several pathways have been proposed for BRONJ occurrence, no single model can explain all morphological changes observed at the macro- and microscopic level. Recent research suggests that BPs may promote an anti-angiogenic effect which contributes directly to the clinical features associated with BRONJ. Remarkably, the anti-angiogenic effect promoting BRONJ might be in keeping with the anti-neoplastic action of BPs. The current review, presents clinical diagnostic criteria. In addition, based on our own experience we describe the histopathological criteria for diagnosis of BRONJ and the possible pathways which may lead to this frustrating pathological condition
Karyotype, Sex Determination, and Meiotic Chromosome Behavior in Two Pholcid (Araneomorphae, Pholcidae) Spiders: Implications for Karyotype Evolution
There are 1,111 species of pholcid spiders, of which less than 2% have published karyotypes. Our aim in this study was to determine the karyotypes and sex determination mechanisms of two species of pholcids: Physocyclus mexicanus (Banks, 1898) and Holocnemus pluchei (Scopoli, 1763), and to observe sex chromosome behavior during meiosis. We constructed karyotypes for P. mexicanus and H. pluchei using information from both living and fixed cells. We found that P. mexicanus has a chromosome number of 2n = 15 in males and 2n = 16 in females with X0-XX sex determination, like other members of the genus Physocyclus. H. pluchei has a chromosome number of 2n = 28 in males and 2n = 28 in females with XY-XX sex determination, which is substantially different from its closest relatives. These data contribute to our knowledge of the evolution of this large and geographically ubiquitous family, and are the first evidence of XY-XX sex determination in pholcids
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