The mechanical behavior and microstructure of highly densified, spherically shaped, polycrystalline Al2O3–YSZ composites, processed from pseudoboehmite powders by sol–gel is reported here. Processing ...was carried out by combining nanometric sized α-Al2O3 (120nm) seeds and YSZ particles of tetragonal structure. The YSZ particles were homogeneously distributed in a coarse-grained matrix of alumina, both inside grains and along grain boundaries. Fracture surfaces, achieved by impact tests showed toughening effects of the zirconia particles. The tetragonality of the YSZ phase stability even after fracture events and fracture toughness measurements by Vickers indentation, where the crack tip interacts with YSZ particles, are all provided and discussed. The local mechanical properties, such as elastic modulus, indentation hardness and the onset of plastic deformation or fracture contact pressure of both YSZ particles and the Al2O3 matrix were quantified by nanoindentation. Evidence of coercive contact pressure was observed in YSZ from indentation stress–strain curves.
Worldwide, lentigo maligna melanoma (LMM) comprises 4%–15% of cutaneous melanoma and occurs less commonly than superficial spreading or nodular subtypes. We assessed the incidence of melanoma ...subtypes in regional and national Surveillance, Epidemiology, and End Results (SEER) cancer registry data from 1990 to 2000. Because 30%–50% of SEER data were not classified by histogenetic type, we compared the observed SEER trends with an age-matched population of 1024 cases from Stanford University Medical Center (SUMC) (1995–2000). SEER data revealed lentigo maligna (LM) as the most prevalent in situ subtype (79%–83%), and that LMM has been increasing at a higher rate compared with other subtypes and to all invasive melanoma combined for patients aged 45–64 and ≥65 y. The SUMC data demonstrated LM and LMM as the only subtypes increasing in incidence over the study period. In both groups, LM comprised ≥75% of in situ melanoma and LMM ≥27% of invasive melanoma in men 65 y and older. Regional and national SEER data suggest an increasing incidence of LM and LMM, particularly in men ≥age 65. An increased incidence of LM subtypes should direct melanoma screening to heavily sun-exposed sites, where these subtypes predominate.
Structural evolution during the synthesis of B2–NiAl intermetallic compound by mechanical alloying of equiatomic elemental mixtures was studied by Rietveld analysis, DSC and HTXRD. The lattice ...parameter, crystallite size, microstrain, amount of phase and ordering of the B2 phase were monitored as a function of milling time. Formation of the B2–NiAl phase shows a sigmoidal behavior, which suggests that Johnson–Mehl–Avrami nucleation and interface-controlled growth are the responsible mechanisms in the transformation. Almost complete transformation (~ 97 mol%) was obtained after 25 h of milling. A specific phase transformation sequence during milling was not absolutely determined, however, the sequence Ni + Al → NiAl
3
→ Ni
2
Al
3
→ B2–NiAl was identified by HTXRD. This sequence was confirmed by DSC. The transformation temperature of the B2–NiAl phase and the presence of additional intermetallic compounds show a direct dependence on the Ni–Al layer spacing. Using a production-scale Simoloyer horizontal Attritor Mill, the presence of Ni
2
Al
3
phase was observed prior to the full synthesis of B2-NiAl.
The θ-Al
2
O
3
→ α-Al
2
O
3
phase transformation was investigated in thermally grown oxide formed on β-(Ni,Pt)Al bond coats during isothermal exposures at 900–1,200 °C in an argon atmosphere stream ...with the O
2
partial pressure of 1 × 10
−5
atm. Local curve fitting was used to evaluate the evolution of the parabolic rate constant,
k
p
, using a general kinetic model (
t
=
A
+
B
Δ
m
+
C
Δ
m
2
), during the first 5 h of oxidation. All net mass–gain curves exhibited deviations from the classic parabolic model, Δ
m
=
k
p
t
½
; a steady state regime was established only after 4 h of exposures, except for the sample oxidized at 1,100 °C.
An oxidation study of
β
-(Ni,Pt)Al commercial bond coat systems was carried by means of TGA analysis during isothermal treatments at temperatures from 1273 K to 1423 K (1000 °C to 1150 °C). The ...effect of oxygen partial pressure on their oxidation kinetics was studied and complemented by photo-stimulated luminescence spectroscopy and SEM. Pre-oxidation treatments performed on as-aluminized samples at 10
−5
atm O
2
did not accelerate the
θ
-Al
2
O
3
→
α
-Al
2
O
3
transformation, even after 5 hours of oxidation relative to samples oxidized in 0.21 atm O
2
, with the exception of the sample treated at 1273 K (1000 °C), where apparently
α
-Al
2
O
3
nucleation started earlier for the sample treated at a low
p
O
2
.
Background: Wound healing following a partial biopsy of basal cell (BCC) and squamous cell carcinomas (SCC) may induce tumor regression.
Methods: Nonmelanoma skin cancer (NMSC) biopsy and re‐excision ...specimens from 1994 to 2001 were reviewed for histologic evidence of scar vs. presence of residual tumor in excision specimens. Regressed and non‐regressed tumors were analyzed to assess the influence of anatomic location, biopsy technique (punch vs. shave), histologic subtype of BCC or SCC, time interval between biopsy and excision, and patient age.
Results: Nine hundred and ten excisions were performed for transected BCC or SCC, 217 (24%) of which showed scar with no residual tumor. Logistic regression analysis revealed significant differences in the regressed vs. non‐regressed subsets. SCCs were more likely to regress than BCCs (40% vs. 20%, respectively, p < 0.00001). Independent of the NMSC type, tumors regressed more often following shave rather than punch biopsy (34% vs. 15%, respectively, p < 0.00001), as did tumors on the trunk and extremities compared with head and neck cases (31% vs. 21%, respectively, p < 0.01).
Conclusions: In our series, 24% of NMSCs transected on the initial biopsy showed no residual tumor in the excision specimens, implying that some event in the interval between biopsy and excision may lead to the eradication of residual tumor. The exact mechanism is unclear, but wound healing likely plays an important role.
An oxidation study of beta -(Ni,Pt)Al commercial bond coat systems was carried by means of TGA analysis during isothermal treatments at temperatures from 1273 K to 1423 K (1000 degree C to 1150 ...degree C). The effect of oxygen partial pressure on their oxidation kinetics was studied and complemented by photo-stimulated luminescence spectroscopy and SEM. Pre-oxidation treatments performed on as-aluminized samples at 10 super(-5) atm O sub(2) did not accelerate the theta -Al sub(2)O sub(3) arrow right alpha -Al sub(2)O sub(3) transformation, even after 5 hours of oxidation relative to samples oxidized in 0.21 atm O sub(2), with the exception of the sample treated at 1273 K (1000 degree C), where apparently alpha -Al sub(2)O sub(3) nucleation started earlier for the sample treated at a low pO sub(2).
An oxidation study of beta-(Ni,Pt)Al commercial bond coat systems was carried by means of TGA analysis during isothermal treatments at temperatures from 1273 K to 1423 K (1000 °C to 1150 °C). The ...effect of oxygen partial pressure on their oxidation kinetics was studied and complemented by photo-stimulated luminescence spectroscopy and SEM. Pre-oxidation treatments performed on as-aluminized samples at 10^sup -5^ atm O2 did not accelerate the theta-Al^sub 2^O3 arrow right alpha-Al^sub 2^O3 transformation, even after 5 hours of oxidation relative to samples oxidized in 0.21 atm O2, with the exception of the sample treated at 1273 K (1000 °C), where apparently alpha-Al^sub 2^O3 nucleation started earlier for the sample treated at a low pO2.PUBLICATION ABSTRACT
The innate immune response is crucial for defense against microbial pathogens. To investigate the molecular choreography of this response, we carried out a systematic examination of the gene ...expression program in human peripheral blood mononuclear cells responding to bacteria and bacterial products. We found a remarkably stereotyped program of gene expression induced by bacterial lipopolysaccharide and diverse killed bacteria. An intricately choreographed expression program devoted to communication between cells was a prominent feature of the response. Other features suggested a molecular program for commitment of antigen-presenting cells to antigens captured in the context of bacterial infection. Despite the striking similarities, there were qualitative and quantitative differences in the responses to different bacteria. Modulation of this host-response program by bacterial virulence mechanisms was an important source of variation in the response to different bacteria.
Myocardial failure has a central role in the complex pathophysiology of septic shock and contributes to organ failure and death. During the sepsis-induced inflammatory process, specific factors are ...released that depress myocardial contractile function. We aimed to identify these mediators of myocardial depression in meningococcal septic shock.
We combined gene-expression profiling with protein and cellular methods to identify a serum factor causing cardiac dysfunction in meningococcal septic shock. We identified genes that were significantly upregulated in blood after exposure to meningococci. We then selected for further analysis those genes whose protein products had properties of a myocardial depressant factor—specifically a 12–25 kDa heat-stable protein that is released into serum shortly after onset of meningococcal infection.
We identified 174 significantly upregulated genes in meningococcus-infected blood: six encoded proteins that were of the predicted size and had characteristics of a myocardial depressant factor. Of these, interleukin 6 caused significant myocardial depression in vitro. Removal of interleukin 6 from serum samples of patients with meningococcaemia and from supernatants of inflammatory cells stimulated by meningococci in vitro abolished the negative inotropic activity. Furthermore, concentrations in serum of interleukin 6 strongly predicted degree of myocardial dysfunction and severity of disease in children with meningococcal septic shock.
Interleukin 6 is a mediator of myocardial depression in meningococcal disease. This cytokine and its downstream mediators could be a target for future treatment strategies.
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