Orthopaedic traumatologists have recognized the unique fracture patterns and injury constellations of pediatric pelvic fractures. However, an understanding of the effect of advancing skeletal ...maturation is needed to avoid applying adult classifications and management. The authors determined how pelvic fracture patterns and management change with advancing skeletal maturity. At their pediatric trauma center, they identified 166 consecutive pelvic fractures. Eighty percent of patients had plain radiographs adequate to evaluate the triradiate cartilage. Physes were scored as open, narrowed, or closed. The Risser sign, fracture pattern, survival after injury, and need for open reduction and internal fixation were recorded. Ninety-seven patients (mean age 5.7 years) had an open triradiate or an “immature pelvis.” Thirty-two patients (mean age 14 years) had a closed triradiate cartilage or a “mature pelvis.” The immature group had a higher propensity for isolated pubic rami and iliac wing fractures. The mature group had a higher predilection for acetabular fractures and pubic or sacroiliac diastasis. All patients requiring open reduction and internal fixation had a mature pelvis. The incidences of specific pelvic fracture patterns between the two groups were statistically different. Management of fractures to the immature pelvis should focus on associated injuries. Once the triradiate cartilage has closed, adult pelvic fracture classifications and management principles should be used.
The observable population of double neutron star (DNS) systems in the Milky Way allow us to understand the nature of supernovae and binary stellar evolution. Until now, all DNS systems in wide orbits ...(\( P_{\textrm{orb}}>\) 1~day) have been found to have orbital eccentricities, \(e > 0.1\). In this paper, we report the discovery of pulsar PSR J1325\(-\)6253: a DNS system in a 1.81 day orbit with a surprisingly low eccentricity of just \(e = 0.064\). Through 1.4 yr of dedicated timing with the Parkes radio telescope we have been able to measure its rate of advance of periastron, \(\dot{\omega}=0.138 \pm 0.002\) \(\rm deg\) \(\rm yr^{-1}\). If this induced \(\dot{\omega}\) is solely due to general relativity then the total mass of the system is, \(M_{\rm sys} = 2.57 \pm 0.06\) M\(_{\odot}\). Assuming an edge-on orbit the minimum companion mass is constrained to be \(M_\mathrm{c,min}>0.98\) M\(_{\odot}\) which implies the pulsar mass is \(M_\mathrm{p,max}<1.59 \) M\(_{\odot}\). Its location in the \(P\)-\(\dot{P}\) diagram suggests that, like other DNS systems, PSR J1325\(-\)6253 is a recycled pulsar and if its mass is similar to the known examples (\(>1.3\) M\(_\odot\)), then the companion neutron star is probably less than \(\sim1.25\) M\(_\odot\) and the system is inclined at about \(50^{\circ}\)-\(60^{\circ}\). The low eccentricity along with the wide orbit of the system strongly favours a formation scenario involving an ultra-stripped supernova explosion.
Solar backscattered ultraviolet (SBUV) ozone profiles have been compared with Stratospheric Aerosol and Gas Experiment (SAGE) II profiles over the period October 1984 through June 1990, when data are ...available from both instruments. SBUV measurements were selected to closely match the SAGE II latitude/longitude measurement pattern. There are significant differences between the SAGE II sunrise and the sunset zonal mean ozone profiles in the equatorial zone, particularly in the upper stratosphere, that may be connected with extreme SAGE II solar azimuth angles for tropical sunrise measurements. Calculation of the average sunset bias between SBUV and SAGE II ozone profiles shows that allowing for diurnal variation in Umkehr layer 10, SBUV and SAGE II agree to within +/- 5% for the entire stratosphere in the northern midlatitude zone. The worst agreement is seen at southern midlatitudes near the ozone peak (disagreements of +/- 10%), apparently the result of the SBUV ozone profile peaking at a lower altitude than SAGE. The integrated ozone columns (cumulative above 15 km) agree very well, to within +/- 2.3% in all zones for both sunset and sunrise measurements. A comparison of the time dependence of SBUV and SAGE II shows that there was less than +/- 5% relative drift over the 5.5 years for all altitudes except below 25 km, where the SBUV vertical resolution is poor. The best agreement with SAGE is seen in the integrated column ozone (cumulative above 15 km), where SAGE II has a 1% negative trend relative to SBUV over the comparison period. There is a persistent disagreement of the two instruments in Umkehr layers 9 and 10 of +/- 4% over the 5.5-year comparison period. In the equatorial zone this disagreement may be caused in part by a large positive trend (0.8 K per year) in the National Meteorologica Center temperatures used to convert the SAGE II measurement of ozone density versus altitude to a pressure scale for comparison with SBUV. In the middle stratosphere (30-40 km), SBUV shows a 2-4% negative drift relative to SAGE II. If the actual ozone trends are considered, SBUV and SAGE II agree in showing little ozone change (less than 2%) between 1984 and 1990, except in layer 3 where SAGE II measures a large ozone decrease. But over 11 years, SBUV measured a 7% per decade ozone decrease between 40 and 50 km, decreasing in magnitude at lower altitudes, in good agreement with 11-year trends derived from the average of 5 Umkehr stations.
An empirically based mathematical model is presented which can simulate the major features of the interactions between ammonium and nitrate transport and assimilation in phytoplankton. The model ...(ammonium-nitrate interaction model), which is configured to simulate a generic microalga rather than a specified species, is constructed on simplified biochemical bases. A major requirement for parametrization is that the N:C ratio of the algae must be known and that transport and internal pool sizes need to be expressed per unit of cell C. The model uses the size of an internal pool of an early organic product of N assimilation (glutamine) to regulate rapid responses in ammonium-nitrate interactions. The synthesis of enzymes for the reduction of nitrate through to ammonium is induced by the size of the internal nitrate pool and repressed by the size of the glutamine pool. The assimilation of intracellular ammonium (into glutamine) is considered to be a constitutive process subjected to regulation by the size of the glutamine pool. Longer term responses have been linked to the nutrient history of the cell using the N:C cell quota. N assimilation in darkness is made a function of the amount of surplus C present and thus only occurs at low values of N:C. The model can simulate both qualitative and quantitative temporal shifts in the ammonium-nitrate interaction, while inclusion of a derivation of the standard quota model enables a concurrent simulation of cell growth and changes in nutrient status.
Abstract
The nocturnal conversion of dinitrogen pentoxide (N
2
O
5
) to nitryl chloride (ClNO
2
) on chloride‐containing aerosol can be a regionally important NO
x
(= NO + NO
2
) recycling and ...halogen activation pathway that affects oxidant photochemistry the following day. Here we present a comprehensive measurement data set acquired at Pasadena, California, during the CalNex‐LA campaign 2010 that included measurements of odd nitrogen and its major components (NO
y
= NO
x
+ NO
3
+ 2N
2
O
5
+ ClNO
2
+ HNO
3
+ HONO + peroxyacyl, alkyl, and aerosol nitrates) and aerosol size distribution and composition. Nitryl chloride was present during every night of the study (median mixing ratio at sunrise 800 pptv) and was usually a more significant nocturnal NO
x
and odd oxygen (O
x
= O
3
+ NO
2
+ 3N
2
O
5
+ ClNO
2
) reservoir species than N
2
O
5
(whose concentrations were calculated from its equilibrium with NO
2
and NO
3
). At sunrise, ClNO
2
accounted for 21% of NO
z
(=NO
y
− NO
x
), 4% of NO
y
, and 2.5% of O
x
, respectively (median values). Kinetic parameters for the N
2
O
5
to ClNO
2
conversion were estimated by relating ClNO
2
concentrations to their time‐integrated heterogeneous production from N
2
O
5
and were highly variable between nights. Production of ClNO
2
required conversion of N
2
O
5
on submicron aerosol with average yield (φ) and N
2
O
5
reactive uptake probability (γ) of γφ = 0.008 (maximum 0.04), scaled with submicron aerosol chloride content, and was suppressed by aerosol organic matter and liquid water content. Not all of the observed variability of ClNO
2
production efficiency could be rationalized using current literature parameterizations.
Key Points
We present field measurements of ClNO2 during Calnex‐LA 2010.
ClNO2 was a more significant nocturnal NOx and Ox reservoir than N2O5.
Rates of N2O5 to ClNO2 conversion varied between nights.
The global obesity epidemic demands an improved understanding of the developmental and environmental factors regulating fat storage. Adipocytes serve as major sites of fat storage and as regulators ...of energy balance and inflammation. The optical transparency of developing zebrafish provides new opportunities to investigate mechanisms governing adipocyte biology, however zebrafish adipocytes remain uncharacterized. We have developed methods for visualizing zebrafish adipocytes in vivo by labeling neutral lipid droplets with Nile Red. Our results establish that neutral lipid droplets first accumulate in visceral adipocytes during larval stages and increase in number and distribution as zebrafish grow. We show that the cellular anatomy of zebrafish adipocytes is similar to mammalian white adipocytes and identify peroxisome-proliferator activated receptor γ and fatty acid binding protein 11a as markers of the zebrafish adipocyte lineage. By monitoring adipocyte development prior to neutral lipid deposition, we find that the first visceral preadipocytes appear in association with the pancreas shortly after initiation of exogenous nutrition. Zebrafish reared in the absence of food fail to form visceral preadipocytes, indicating that exogenous nutrition is required for adipocyte development. These results reveal homologies between zebrafish and mammalian adipocytes and establish the zebrafish as a new model for adipocyte research.
Retroperitoneal iliac procedures can enable successful endovascular repair of abdominal aortic aneurysm (AAA) in patients who otherwise would not be anatomically eligible. The purpose of this study ...was to determine perioperative outcome with adjunctive retroperitoneal procedures compared with standard bilateral femoral exposure.
Between August 1997 and November 2002, 164 patients underwent elective endovascular AAA repair at a single university medical center. Anatomic, demographic, and early postoperative outcome data gathered prospectively were analyzed. Thirty-two patients (20%) underwent 38 separate adjunctive retroperitoneal procedures. Indications included small external iliac arteries (16 of 32 patients; 50%) and concomitant iliac aneurysm that precluded fixation of the endograft limbs in the common iliac arteries (16 of 32 patients; 50%). The 38 procedures consisted of 8 iliac conduits only, 14 iliac conduits with iliofemoral bypass grafts, and 16 hypogastric revascularization procedures. Data for the study patients were compared with data for 132 patients who underwent endovascular AAA repair through femoral incisions. Primary end points were hospital length of stay, and early morbidity and mortality.
Retroperitoneal procedures enabled an additional 14% of patients with AAA to undergo endovascular techniques. However, there was a significantly higher proportion of women and patients at high risk for anesthesia (American Society of Anesthesiologists class IV or higher) in the group who underwent retroperitoneal procedures. On average, retroperitoneal procedures were associated with 2.6-fold greater blood loss, 82% longer procedure time, 1.5 days additional hospital stay, and 1.8-fold higher rate of perioperative complications, compared with endovascular AAA repair with femoral exposure alone. In contrast, early mortality was similar in the two groups.
Adjunctive retroperitoneal procedures during endovascular AAA repair are associated with increased risk for complications and longer hospital length of stay, compared with AAA repair with standard femoral exposure only. They do not, however, increase early mortality, even in patients at high risk, and enable a larger subset of patients with AAA to undergo endovascular repair.
The majority of research has focused on the association between trans unsaturated fatty acids (TUFA) from hydrogenated vegetable oils and heart disease even though TUFA are also produced from ...hydrogenated fish oil. We compared the acute effect of three solid fats on postprandial cholesterol, triacylglycerol (TAG) and NEFA concentrations in normocholesterolaemic males. Eight healthy male volunteers consumed each of the three 40g fat meals (partially hydrogenated fish oil (PHFO), palm oil and lard) in random order and blood samples were drawn at 2, 4, 6 and 8h thereafter for lipid analysis. The postprandial response in plasma TAG, TAG-rich lipoprotein-TAG (TRL-TAG), total cholesterol and plasma NEFA, measured as the area under the postprandial curve, was not significantly different between the three meals (p>0·05), which varied in MUFA, PUFA and TUFA content. There was no marked elevation of longer-chain fatty acids (C20–22, cis or trans isomers) into the TRL-TAG fraction following the PHFO meal even though they provided 40% of the total fatty acids in the PHFO meal. The postprandial TRL-TAG response to PHFO was expected to be higher, as it is higher in TUFA, lower in PUFA and similar in saturated fatty acid composition compared with the lard and palm oil test meals. The absence of a higher postprandial response following ingestion of PHFO could be as a result of reduced absorption and increased oxidation of long-chain fatty acids (both cis and trans isomers)
To describe the clinical features, association with von Hippel-Lindau (VHL) disease and visual acuity outcomes of patients with a juxtapapillary capillary hemangioma.
Retrospective observational case ...series.
Seventy-two eyes of 68 patients identified with a juxtapapillary capillary hemangioma. Follow-up data of at least 6 months duration were available for 60 eyes.
A retrospective chart review of patients diagnosed with a juxtapapillary capillary hemangioma examined at four medical centers.
Age at diagnosis, visual acuity (VA) at first examination and at last follow-up, tumor growth pattern and location, associated clinical features, type of treatment, association with VHL, and presence of peripheral hemangiomas were recorded for each patient.
On initial examination, VA was ≥20/40 in 43 of 70 eyes (61%) and was ≥20/200 in 60 eyes (86%). At an average follow-up of 5.4 years (range, 0.5–19 years), VA of ≥20/40 was achieved in 21 eyes (35%) and ≥20/200 in 33 eyes (55%). Patients with VHL had poorer initial VA (48% vs. 70% with VA ≥20/40, and 74% vs. 93% with VA ≥20/200) and final VA (26% vs. 41% with VA ≥20/40, and 39% vs. 65% with VA ≥20/200) compared with patients without VHL. Patients with VHL more commonly were seen at an earlier age (average, 20 vs. 44 years,
P < 0.001), with bilateral (17% vs. 0%), and/or peripheral (39% vs. 0%) (
P < 0.001) tumors that more often had an endophytic growth pattern (63% vs. 22%,
P = 0.001) compared with patients without VHL. Patients selected for laser treatment generally had poorer initial (52% vs. 74% with VA ≥20/40, 79% vs. 96% with VA ≥20/200) and final VAs (18% vs. 56% with VA ≥20/40, 45% vs. 67% with VA ≥20/200) compared with patients not treated with laser.
On long-term follow-up of patients with a juxtapapillary capillary hemangioma, the VA generally worsens. Patients with VHL and a juxtapapillary hemangioma more often present at a younger age, have tumors with an endophytic growth pattern, and have bilateral, multiple tumors. Treatment with laser photocoagulation results in variable VA outcomes.
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