Spodosols of the S.E. USA occur mainly on poorly-drained “flatwoods” landscapes. Their Bh horizons constitute a globally significant pool of subsurface carbon (C) but mechanisms of the hydrologic ...linkage are uncertain.
This study was to determine relations between iron (Fe), aluminum (Al) and C along transitions between poorly-drained Aquods and better drained Udults and to evaluate mechanistic implications.
Twenty three soil profiles were described and sampled along four 80–120m transects corresponding to drainage gradients documented by wells over a 2.5-year period. Soils showed a typical transitional trend of upward fading Bh horizon as the drier end of the gradient was approached. Iron and Al concentrations in extracting solutions of pyrophosphate (Fep and Alp), ammonium oxalate (Feaao and Alaao), and citrate–dithionite–bicarbonate (Fecdb and Alcdb) were determined by ICP. Pyrophosphate-extractable (Cp) and total C (Ct) were determined by flash combustion.
Declining strength of Bh expression with increasing mean water table depth suggests that regional podzolization is largely affected by the frequency at which near-surface saturation occurs at a sufficient duration to reach certain moisture-driven biogeochemical thresholds. Results confirmed declining Fe from weak Bh horizons of drier soil to well expressed Bh horizons of Aquods. Pyrophosphate-extractable Al, but not Fep, related positively with Cp and Ct. Thus depletion of Fe and retention of C and Al in Bh horizons accompany increasing wetness and degree of podzolic expression, implicating Fe as a possible inhibitor of the process. Alternatively, preemptive redox depletion of Fe could occur prior to onset of podzolic thresholds associated with wetness (e.g., DOC activity). Persistence of Fe and its correlation with Al in weak Bh horizons indicate spatial overlap in its redox and podzolic redistribution. The pH decreased with increasing C for all horizons suggesting that acidity is controlled more by organic acids than by metal hydrolysis. Ratios of Cp/Ct and Alp/Ct as well as slope between Cp and Ct could be used to distinguish Bh- from A-horizon materials. Eluvial–illuvial relations between E and Bh were confirmed for clay as well as metals.
The morphological transition from Udults to Aquods parallels hydrological, chemical, and compositional changes. Implications of these changes are that Al and C distributions are mainly controlled by podzolization whereas Fe concentrations diminish with progressive wetness and podzolization. These results implicate Fe as a possible inhibitor of the process for southern Spodosols. However, its higher concentration and correlation with Al in weak Bh horizons indicate limited podzolic redistribution of Fe in marginally wet zones. The results are pertinent to the effects of hydrologic change on C and metal distributions in soils of S.E. USA coastal plain landscapes.
•Spodosols of S.E. USA are mostly poorly drained & a huge subsurface carbon (C) pool.•Hydrologic gradient is a factor in transition of Udults to Aquods.•Iron (Fe) depletion thresholds precede podzolic thresholds in Aquod formation.•Fluctuating water table promotes C & aluminum (Al) association to form Bh.•Ap & weak Bh horizons can be distinguished using Al/C ratio.
BACKGROUND: Avian influenza viruses (AIVs) are found worldwide in numerous bird species, causing significant disease in gallinaceous poultry and occasionally other species. Surveillance of wild bird ...reservoirs provides an opportunity to add to the understanding of the epidemiology of AIVs. METHODS: This study examined key findings from the National Avian Influenza Wild Bird Surveillance Program over a 5‐year period (July 2007–June 2012), the main source of information on AIVs circulating in Australia. RESULTS: The overall proportion of birds that tested positive for influenza A via PCR was 1.9 ± 0.1%, with evidence of widespread exposure of Australian wild birds to most low pathogenic avian influenza (LPAI) subtypes (H1–13, H16). LPAI H5 subtypes were found to be dominant and widespread during this 5‐year period. CONCLUSION: Given Australia's isolation, both geographically and ecologically, it is important for Australia not to assume that the epidemiology of AIV from other geographic regions applies here. Despite all previous highly pathogenic avian influenza outbreaks in Australian poultry being attributed to H7 subtypes, widespread detection of H5 subtypes in wild birds may represent an ongoing risk to the Australian poultry industry.
We have examined the relationships between dementia, loss of synaptic proteins, changes in the cytoskeleton, and deposition of β-amyloid plaques in the neocortex in a clinicopathologically staged ...epidemiological cohort using a combination of biochemical and morphometric techniques. We report that loss of synaptic proteins is a late-stage phenomenon, occurring only at Braak stages 5 and 6, or at moderate to severe clinical grades of dementia. Loss of synaptic proteins was seen only after the emergence of the full spectrum of tau and β-amyloid pathology in the neocortex at stage 4, but not in the presence of β-amyloid plaques alone. Contrary to previous studies, we report increases in the levels of synaptophysin, syntaxin, and SNAP-25 at stage 3 and of α-synuclein and MAP2 at stage 4. Minimal and mild clinical grades of dementia were associated with either unchanged or elevated levels of synaptic proteins in the neocortex. Progressive aggregation of paired helical filament (PHF)-tau protein could be detected biochemically from stage 2 onwards, and this was earliest change relative to the normal aging background defined by Braak stage 1 that we were able to detect in the neocortex. These results are consistent with the possibility that failure of axonal transport associated with early aggregation of tau protein elicits a transient adaptive synaptic response to partial de-afferentation that may be mediated by trophic factors. This early abnormality in cytoskeletal function may contribute directly to the earliest clinically detectable stages of dementia.
Two uranium–thorium–zirconium hydrides, (UTh
4Zr
10)H
1.9 and (U
4Th
2Zr
9)H
1.5, have been fabricated and characterized. Fabrication involved arc melting of the constituent pure metals to form ...homogenous alloys, followed by hydriding at elevated temperatures in a hydrogen gas environment. The compounds were characterized by X-ray powder diffractometry as well as scanning and transmission electron microscopy. These methods revealed a multi-phase mixture of δ-zirconium hydride (ZrH
1.6+
x
), thorium–zirconium hydride (ThZr
2H
7−
x
), and uranium metal. The elastic modulus was mapped across the microstructure using nanoscale dynamic stiffness mapping. The elastic modulus of ThZr
2H
7−
x
phase is found to be 172
GPa.
We used gene expression profiling to establish a molecular diagnosis of mantle cell lymphoma (MCL), to elucidate its pathogenesis, and to predict the length of survival of these patients. An MCL gene ...expression signature defined a large subset of MCLs that expressed cyclin D1 and a novel subset that lacked cyclin D1 expression. A precise measurement of tumor cell proliferation, provided by the expression of proliferation signature genes, identified patient subsets that differed by more than 5 years in median survival. Differences in cyclin D1 mRNA abundance synergized with INK4a/ARF locus deletions to dictate tumor proliferation rate and survival. We propose a quantitative model of the aberrant cell cycle regulation in MCL that provides a rationale for the design of cell cycle inhibitor therapy in this malignancy.
Pelvic organ prolapse is usually caused by weakness of the pelvic diaphragm. Descent of the pelvic diaphragm places stress on the endopelvic connective tissue support system. Subsequent increases in ...intra-abdominal pressure result in prolapse. In the majority of cases, labor and childbirth are thought to be the primary factors responsible for pelvic neuropathies and tissue damage that predispose to the development of POP. Certain connective tissue defects, congenital defects, and operative procedures also contribute to pelvic support defects.
Forty-seven women had urethral pressure profile determinations performed at rest and during a Kegel pelvic muscle contraction, after brief standardized verbal instruction. Twenty-three (49%) had an ...ideal Kegel effort--a significant increase in the force of urethral closure without an appreciable Valsalva effort. Twelve subjects (25%) displayed a Kegel technique that could potentially promote incontinence. Age, parity, weight, estrogen deprivation, prior continence surgery or hysterectomy, and passive urethral function did not predict a successful effort. We concluded that simple verbal or written instruction does not represent adequate preparation for a patient who is about to start a Kegel exercise program.
α-Synuclein has assumed particular neuropathological interest in the light both of its identification as a non-β-amyloid plaque constituent in Alzheimer disease (AD), and the recent association ...between dominant inheritance of Parkinson disease (PD) and 2 missense mutations at positions 30 and 53 of the synuclein protein. We report a systematic study of α-synuclein, tau, and ubiquitin immunoreactivity in representative neurodegenerative disorders of late life. The α-synuclein association with Lewy bodies is variable, peripheral, and is not stable with respect to proteases or acid treatment, whereas there is no association with Pick bodies. Stable patterns of immunoreactivity included neurites and a novel inclusion body. Although there is an overlap between the presence of Lewy bodies and stable α-synuclein immunoreactivity, this is seen only in the presence of concomitant neuropathological features of AD. The novel α-synuclein inclusion body identified in pyramidal cells of the medial temporal lobe in particular was found in AD and in the Lewy body variant of AD, and was associated neither with ubiquitin nor tau protein. The inclusion is therefore neither a Lewy body nor a PHF-core body, but may be confused with the Lewy body, particularly in the Lewy body variant of AD. Abnormal processing of α-synuclein leading to its deposition in the form of proteolytically stable deposits is a particular feature of the intermediate stages of AD.
OBJECTIVE: Severe prolapse may mask potential genuine stress urinary incontinence in women. Some have suggested that a suspending urethropexy be performed in women who have potential genuine stress ...incontinence demonstrated by barrier reduction of the prolapse preoperatively. Our aim was to compare outcomes after prolapse surgery that included a formal bladder neck suspension with those operations that did not.
STUDY DESIGN: This prospective randomized clinical trial assigned 32 women with bladder neck hypermobility and stage III or IV pelvic organ prolapse to receive either a needle colposuspension or bladder neck endopelvic fascia plication as part of the vaginal reconstructive surgery. Twenty-nine subjects underwent detailed clinical, anatomic, urodynamic, and quality-of-life evaluations before and 6 weeks and 6 months after surgery; 23 completed urinary diary and quality-of-life evaluations after a mean of 2.9 years.
RESULTS: Needle colposuspension increased short-term complications without providing additional protection from de novo stress incontinence. Barrier testing before surgery predicted urethral sphincteric resistance after surgery; however, such testing neither predicted a patient's function after surgery nor indicated the need for a suspending urethropexy. The combination of a needle colposuspension with a sacrospinous ligament suspension predisposed to the early development of support defects of the upper anterior vaginal segment and to failure of bladder neck support.
CONCLUSIONS: Preoperative barrier testing in women with severe prolapse is not useful in identifying individuals who require a suspending urethropexy. Needle colposuspension increases short-term complications, lacks durability, and may predispose to early and severe recurrent anterior prolapse when performed with a sacrospinous ligament vault suspension. (Am J Obstet Gynecol 1996;175:326-35.)
To assess the relationship between either bacterial vaginosis or trichomoniasis vaginitis and posthysterectomy infection, preoperative evaluation of the vaginal secretions was performed in 161 women ...undergoing abdominal hysterectomy. Thirty-two patients (19.9%) and 27 patients (16.8%), respectively, met the diagnostic criteria for bacterial vaginosis and trichomoniasis vaginitis. Patients with either bacterial vaginosis or trichomoniasis vaginitis were more likely than control subjects to have cuff cellulitis, cuff abscess, or both (relative risk 3.2, 95% confidence interval 1.5 to 6.7 for bacterial vaginosis; relative risk 3.4, 95% confidence interval 1.6 to 7.1 for trichomoniasis vaginitis). Preoperative vaginitis had no effect with respect to the incidence of postoperative wound infection, urinary tract infection, or intravenous line phlebitis. Bacteroides sp., Peptostreptococcus sp., and/or Gardnerella vaginalis ("bacterial vaginosis organisms") were isolated from the vaginal cuff in the majority of patients with postoperative cuff cellulitis. Bacterial vaginosis and trichomoniasis vaginitis are risk factors for the development of posthysterectomy cuff cellulitis.
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