The carbon net negative conversion of bio-char, the low value byproduct of pyrolysis bio-oil production from biomass, to high value, very high purity, highly crystalline flake graphite agglomerates ...with rationally designed shape and size tailored for lithium-ion battery energy storage material is reported. The process is highly efficient, 0.41 g/Wh; the energy content of its co-product of the process, bio-oil, exceeds that needed to power the process. It is shown that the shape of the starting material is retained during the transformation, allowing the ultimate morphology of the graphite agglomerates to be engineered from relatively malleable biomass. In contrast to commercial graphite production, the process can be performed at small scale with low equipment costs, enabling individual research laboratories to produce Li-ion grade graphite with customizable shape, size and porosity for Si/graphite composite and other graphite involved anodes. The mechanism of the graphitization of bio-char, a "non-graphitizable" carbon, is explored, suggesting the molten metal catalyst is absorbed into the pore structure, transported through and transforming the largely immobile biochar. Finally, the transformation of biomass to rationally designed graphite morphologies with Li-ion anode performance that closely mimic commercial shaped graphite is demonstrated.
Understanding the transformation of graphitic carbon nitride (g-C3N4) is essential to assess nanomaterial robustness and environmental risks. Using an integrated experimental and simulation approach, ...our work has demonstrated that the photoinduced hole (h+) on g-C3N4 nanosheets significantly enhances nanomaterial decomposition under •OH attack. Two g-C3N4 nanosheet samples D and M2 were synthesized, among which M2 had more pores, defects, and edges, and they were subjected to treatments with •OH alone and both •OH and h+. Both D and M2 were oxidized and released nitrate and soluble organic fragments, and M2 was more susceptible to oxidation. Particularly, h+ increased the nitrate release rate by 3.37–6.33 times even though the steady-state concentration of •OH was similar. Molecular simulations highlighted that •OH only attacked a limited number of edge-site heptazines on g-C3N4 nanosheets and resulted in peripheral etching and slow degradation, whereas h+ decreased the activation energy barrier of C–N bond breaking between heptazines, shifted the degradation pathway to bulk fragmentation, and thus led to much faster degradation. This discovery not only sheds light on the unique environmental transformation of emerging photoreactive nanomaterials but also provides guidelines for designing robust nanomaterials for engineering applications.
The carbon net negative conversion of biochar, the byproduct of pyrolysis bio-oil production from biomass, to very high-purity (99.95%), highly crystalline flake graphite that is essentially ...indistinguishable from high-grade commercial Li-ion grade graphite, is reported. The flake size of the graphite is determined by the physical dimensions of the metal particles imbedded in the biochar, demonstrated in the range of micrometers to millimeters. “Potato”-shaped agglomerates of graphite flakes result when the flake diameter is in the 1–5 μm range. The process is shown to work with a variety of biomass, including raw lignocellulose (sawdust, wood flour, and corn cob) and biomass components (cellulose and lignin), as well as lignite. The synthesis is extremely rapid and energy efficient (0.25 kg/kWh); the graphite is produced with a very high yield (95.7%), and the energy content of its coproduct, bio-oil, exceeds that needed to power the process. The demonstrated process is a tremendous advance in the sustainability of graphite production, currently commercially mined or synthesized with very high environmental impacts, and results in a value-added product that could economically advantage carbon-neutral bio-oil production.
A rigorous comparison of cervical cancer screening methods utilizing data on immune status, antiretroviral therapy (ART) and colposcopy-directed biopsy has not been performed among HIV-positive ...women.
Between June and November 2009, 500 HIV-positive women were enrolled at an HIV treatment clinic in Nairobi, Kenya, and underwent Papanicolau (Pap) smear, visual inspection with acetic acid (VIA), human papillomavirus (HPV) and colposcopy-directed biopsy (gold standard). Positive Pap smear (ASCUS+, LSIL+, HSIL+), VIA, HPV and their combinations were compared with CIN2/3+. Sensitivity, specificity and AUC (sensitivity and 1-specificity) were compared using pairwise tests and multivariate logistic regression models that included age, CD4⁺ cell count and ART duration.
Of 500 enrolled, 498 samples were collected. On histology, there were 172 (35%) normal, 186 (37%) CIN1, 66 (13%) CIN2, 47 (9%) CIN3 and 27 (5%) indeterminate. Pap (ASCUS+) was the most sensitive screening method (92.7%), combination of both Pap (HSIL+) and VIA positive was the most specific (99.1%) and Pap (HSIL+) had the highest AUC (0.85). In multivariate analyses, CD4⁺ cell count of 350 cells/μl or less was associated with decreased HPV specificity (P = 0.002); ART duration of less than 2 years was associated with decreased HPV (P = 0.01) and VIA (P = 0.03) specificity; and age less than 40 years was associated with increased VIA sensitivity (P < 0.001) and decreased HPV specificity (P = 0.005).
Pap smear is a robust test among HIV-positive women regardless of immune status or ART duration. Results should be cautiously interpreted when using HPV among those younger, immunosuppressed or on ART less than 2 years, and when using VIA among those aged 40 years or more.
Vicissitudes of laughter McKenzie, Kevin
Pragmatics : quarterly publication of the International Pragmatics Association,
7/2022
Journal Article
Recenzirano
Abstract This paper is concerned with the way that laughter is employed to manage threats to interlocutor affiliation in talk among humanitarian aid workers as they describe their professional ...activities in settings of armed conflict. I first set out to situate my analysis within the tradition of work in ethnomethodology and conversation analysis (EM), exploring how that approach differs in significant ways from work in pragmatics and related traditions of discourse analytic research. Unlike the latter approaches, EM examines laughter for the intelligibility it is deployed by speakers to furnish, so that the presumption of laughter’s revelatory nature which characterizes a pragmatically-oriented analysis is seen as a participant resource for rendering the situated significance of actions visible by and for the involved parties of a given episode of interaction. Following this, I examine talk from open-ended interviews with aid agency operatives who work in Israel and the Palestinian Territories, exploring how laughter is employed to manage threats to interlocutor affiliation where the potential accusation of opportunism arises in accounts of personal job satisfaction as against the legitimacy otherwise afforded with an appeal to altruism and self-sacrifice. Where speakers attend to the criticism of humanitarian activity for its significance in affecting outcomes of warfare, the management of these different demands is accomplished in reflexive work to ironize their own and others’ formulations of motivation for pursuing humanitarian work.
To assess residual cervical intraepithelial neoplasia (CIN) 2/3 disease and clearance of high-risk (hr) human papillomavirus (HPV) infections at 6 months after cryotherapy among HIV-positive women.
...Follow-up study.
79 HIV-positive women received cryotherapy for CIN2/3 in Nairobi, Kenya, and underwent conventional cytology 6 months later. Biopsies were performed on high grade cytological lesions and hrHPV was assessed before (cervical cells and biopsy) and after cryotherapy (cells).
At 6 months after cryotherapy CIN2/3 had been eliminated in 61 women (77.2%; 95% Confidence Interval, (CI): 66.4-85.9). 18 women (22.8%) had residual CIN2/3, and all these women had hrHPV at baseline. CD4 count and duration of combination antiretroviral therapy (cART) were not associated with residual CIN2/3. CIN3 instead of CIN2 was the only significant risk factor for residual disease (odds ratio, OR vs CIN2 = 4.3; 95% CI: 1.2-15.0) among hrHPV-positive women after adjustment for age and HPV16 infection. Persistence of hrHPV types previously detected in biopsies was found in 77.5% of women and was associated with residual CIN2/3 (OR = 8.1, 95% CI: 0.9-70). The sensitivity, specificity, and negative predictive value of hrHPV test in detecting residual CIN2/3 were 0.94, 0.36, and 0.96 respectively.
Nearly one quarter of HIV-positive women had residual CIN2/3 disease at 6 months after cryotherapy, and the majority had persistent hrHPV. CD4 count and cART use were not associated with residual disease or hrHPV persistence. The value of hrHPV testing in the detection of residual CIN2/3 was hampered by a low specificity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The prevalence of cervical squamous intraepithelial lesions (SIL) among HIV-infected women on antiretroviral therapy in sub-Saharan Africa has not been well described.
HIV-infected women enrolled in ...an HIV treatment clinic in Nairobi, Kenya were offered free cervical screening with Papanicolaou (Pap) smear testing if they were 30 to 39 years of age and on antiretroviral therapy. Women with SIL were compared to those without SIL with univariate analyses and logistic regression.
Of 595 eligible women, 267 accepted Pap testing and had available cytology results, of whom 258 (97%) were on a non-nucleoside reverse transcriptase inhibitor (NNRTI) based regimen. Median duration of antiretroviral therapy was 13 months interquartile range (IQR), 8-19. Abnormal cytology was found in 123 women (46%) with 70 women (26%) having low grade squamous intraepithelial lesions (LSIL), 22 (8%) high grade squamous intraepithelial lesions (HSIL), 30(11%) atypical squamous cells of unknown significance (ASCUS) and 1 (0.4%) atypical glandular cells (AGC). Women with SIL had lower median CD4 cell count (239 vs 287 cells/mm3; P=0.02), lower income (<70 USD per month: 57% vs 38%; P=0.01), and less regular condom use (24% vs 40%; P=0.02) compared to those with no SIL. Duration and type of antiretroviral regimen were not significantly associated with SIL.
SIL is prevalent among women on antiretroviral therapy and is associated with immunosuppression, low income, and less frequent condom use. Cervical cancer screening and counseling on condom use should be routinely offered to HIV-infected women in antiretroviral treatment clinics in Africa.
To determine the effect of cryotherapy on HIV-1 cervical shedding.
Prospective cohort study.
Five hundred HIV-positive women enrolled at an HIV treatment clinic in Nairobi, Kenya were screened for ...cervical cancer. Women diagnosed with cervical intraepithelial neoplasia stage 2 or 3 (CIN 2/3) by histology were offered cryotherapy treatment. The first 50 women had cervical swabs taken at baseline and at 2 and 4 weeks following treatment. Swabs were analyzed for HIV-1 RNA and compared using General Estimating Equation (GEE) with binomial or Gaussian links.
Of the 50 women enrolled, 40 were receiving antiretroviral therapy (ART) and 10 were not receiving ART at the time of cryotherapy and during study follow-up. Among all women, the odds of detectable cervical HIV-1 RNA did not increase at 2 weeks odds ratio (OR) 1.18; 95% confidence interval (CI) 0.65-2.13 or 4 weeks (OR 1.29; 95% CI 0.71-2.33) following cryotherapy. Among 10 women not receiving ART, the OR of detectable shedding at 2 weeks was higher, but not statistically significant (OR 4.02; 95% CI 0.53-30.79; P = 0.2), and at 4 weeks remained unchanged (OR 1.00; 95% CI 0.27-3.74).
There was no increase in detectable cervical HIV-1 RNA among HIV-positive women after cryotherapy. The risk of HIV-1 transmission after cryotherapy may not be significant, particularly among women already on ART at the time of cervical treatment. However, further investigation is needed among women not receiving ART.
Steroidogenic acute regulatory protein facilitates the translocation of cholesterol to the inner mitochondrial membrane, thereby initiating steroidogenesis. At the inner mitochondrial membrane, ...cytochrome P450 side-chain cleavage enzyme converts cholesterol to pregnenolone, an oxidative process requiring electrons from NADPH. Pregnenolone then serves as the substrate for the formation of progesterone or dehydroepiandrosterone by downstream enzymes. Studies have shown that cigarette smoke (CS) influences steroid hormone levels. To better understand the underlying mechanisms, we used a mouse model to study the effects of chronic CS exposure on steroidogenesis. Through radioimmunoassay and metabolic conversion assays, we found that CS reduced progesterone and dehydroepiandrosterone without affecting cytochrome P450 side-chain cleavage enzyme or 3β-hydroxysteroid dehydrogenase 2 expression. However, CS did reduce expression of cytochrome c oxidase IV (COX IV), a component of the mitochondrial complex that serves as the last enzyme in the electron transport chain. Small interfering RNA-mediated COX IV knockdown indeed decreased progesterone synthesis in steroidogenic cells. In summary, COX IV likely plays a role in steroidogenesis, and passive smoking may negatively affect steroidogenesis by disrupting the electron transport chain.
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