Long-term perspective on wildfires in the western USA Marlon, Jennifer R; Bartlein, Patrick J; Gavin, Daniel G ...
Proceedings of the National Academy of Sciences,
02/2012, Letnik:
109, Številka:
9
Journal Article
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Odprti dostop
Understanding the causes and consequences of wildfires in forests of the western United States requires integrated information about fire, climate changes, and human activity on multiple temporal ...scales. We use sedimentary charcoal accumulation rates to construct long-term variations in fire during the past 3,000 y in the American West and compare this record to independent fire-history data from historical records and fire scars. There has been a slight decline in burning over the past 3,000 y, with the lowest levels attained during the 20th century and during the Little Ice Age (LIA, ca. 1400–1700 CE Common Era). Prominent peaks in forest fires occurred during the Medieval Climate Anomaly (ca. 950–1250 CE) and during the 1800s. Analysis of climate reconstructions beginning from 500 CE and population data show that temperature and drought predict changes in biomass burning up to the late 1800s CE. Since the late 1800s , human activities and the ecological effects of recent high fire activity caused a large, abrupt decline in burning similar to the LIA fire decline. Consequently, there is now a forest "fire deficit" in the western United States attributable to the combined effects of human activities, ecological, and climate changes. Large fires in the late 20th and 21st century fires have begun to address the fire deficit, but it is continuing to grow.
The compounds and complexes 1,4‐C6H4(C≡C‐cyclo‐3‐C4H3S)2 (2), trans‐Pt(C≡C‐cyclo‐3‐C4H3S)2(PEt3)2 (3), trans‐Ru(C≡C‐cyclo‐3‐C4H3S)2(dppe)2 (4; dppe=1,2‐bis(diphenylphosphino)ethane) and ...trans‐Ru(C≡C‐cyclo‐3‐C4H3S)2{P(OEt)3}4 (5) featuring the 3‐thienyl moiety as a surface contacting group for gold electrodes have been prepared, crystallographically characterised in the case of 3–5 and studied in metal|molecule|metal junctions by using both scanning tunnelling microscope break‐junction (STM‐BJ) and STM‐I(s) methods (measuring the tunnelling current (I) as a function of distance (s)). The compounds exhibit similar conductance profiles, with a low conductance feature being more readily identified by STM‐I(s) methods, and a higher feature by the STM‐BJ method. The lower conductance feature was further characterised by analysis using an unsupervised, automated multi‐parameter vector classification (MPVC) of the conductance traces. The combination of similarly structured HOMOs and non‐resonant tunnelling mechanism accounts for the remarkably similar conductance values across the chemically distinct members of the family 2–5.
Conducting alone: The single‐molecule conductance of 3‐thienyl contacted organic and organometallic complexes displays remarkable invariance, as determined by both scanning tunnelling microscope break‐junction (STM‐BJ) analysis and I(s) measurements.
Evolution of minimal DNA tumor virus' genomes has selected for small viral oncoproteins that hijack critical cellular protein interaction networks. The structural basis for the multiple and dominant ...functions of adenovirus oncoproteins has remained elusive. E4-ORF3 forms a nuclear polymer and simultaneously inactivates p53, PML, TRIM24, and MRE11/RAD50/NBS1 (MRN) tumor suppressors. We identify oligomerization mutants and solve the crystal structure of E4-ORF3. E4-ORF3 forms a dimer with a central β core, and its structure is unrelated to known polymers or oncogenes. E4-ORF3 dimer units coassemble through reciprocal and nonreciprocal exchanges of their C-terminal tails. This results in linear and branched oligomer chains that further assemble in variable arrangements to form a polymer network that partitions the nuclear volume. E4-ORF3 assembly creates avidity-driven interactions with PML and an emergent MRN binding interface. This reveals an elegant structural solution whereby a small protein forms a multivalent matrix that traps disparate tumor suppressors.
Background
Few studies describe acute kidney injury (AKI) burden during paediatric cisplatin therapy and post-cisplatin kidney outcomes. We determined risk factors for and rate of (1) AKI during ...cisplatin therapy, (2) chronic kidney disease (CKD) and hypertension 2–6 months post-cisplatin, and (3) whether AKI is associated with 2–6-month outcomes.
Methods
This prospective cohort study enrolled children (aged < 18 years at cancer diagnosis) treated with cisplatin from twelve Canadian hospitals. AKI during cisplatin therapy (primary exposure) was defined based on Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria (≥ stage one). Severe electrolyte abnormalities (secondary exposure) included ≥ grade three hypophosphatemia, hypokalemia, or hypomagnesemia (National Cancer Institute Common Terminology Criteria for Adverse Events v4.0). CKD was albuminuria
or
decreased kidney function for age (KDIGO guidelines). Hypertension was defined based on the 2017 American Academy of Pediatrics guidelines.
Results
Of 159 children (median interquartile range IQR age: 6 2–12 years), 73/159 (46%) participants developed AKI and 55/159 (35%) experienced severe electrolyte abnormalities during cisplatin therapy. At median IQR 90 76–110 days post-cisplatin, 53/119 (45%) had CKD and 18/128 (14%) developed hypertension. In multivariable analyses, AKI was not associated with 2–6-month CKD or hypertension. Severe electrolyte abnormalities during cisplatin were associated with having 2–6-month CKD
or
hypertension (adjusted odds ratio (AdjOR) 95% CI: 2.65 1.04–6.74). Having both AKI
and
severe electrolyte abnormalities was associated with 2–6-month hypertension (AdjOR 95% CI: 3.64 1.05–12.62).
Conclusions
Severe electrolyte abnormalities were associated with kidney outcomes. Cisplatin dose optimization to reduce toxicity and clear post-cisplatin kidney follow-up guidelines are needed.
Graphical abstract
A higher resolution version of the Graphical abstract is available as
Supplementary information
Background
Cisplatin is associated with acute kidney injury (AKI) and electrolyte abnormalities. Urine tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor-binding protein ...7 (IGFBP-7) may be early cisplatin-AKI biomarkers.
Methods
We conducted a 12-site prospective cohort study with pediatric patients treated with cisplatin (May 2013–December 2017). Blood and urine (measured for TIMP-2, IGFBP-7) were collected pre-cisplatin, 24-h post-cisplatin, and near hospital discharge during the first or second cisplatin cycle (early visit (EV)) and during second-to-last or last cisplatin cycle (late visit (LV)). Primary outcome: serum creatinine (SCr)-defined AKI (≥ stage 1).
Results
At EV (median (interquartile (IQR)) age: 6 (2–12) years; 78 (50%) female), 46/156 (29%) developed AKI; at LV, 22/127 (17%) experienced AKI. At EV, TIMP-2, IGFBP-7, and TIMP-2*IGFBP-7 pre-cisplatin infusion concentrations were significantly higher in participants with vs. those without AKI. At EV and LV, biomarker concentrations were significantly lower in participants with vs. those without AKI at post-infusion and near-hospital discharge. Biomarker values normalized to urine creatinine were higher in patients with AKI compared to without (LV post-infusion, median (IQR): TIMP-2*IGFBP-7: 0.28 (0.08–0.56) vs
.
0.04 (0.02–0.12) (ng/mg creatinine)
2
/1000;
P
< .001). At EV, pre-infusion biomarker concentrations had the highest area under the curves (AUC) (range: 0.61–0.62) for AKI diagnosis; at LV, biomarkers measured post-infusion and near discharge yielded the highest AUCs (range: 0.64–0.70).
Conclusions
TIMP-2*IGFBP-7 were poor to modest at detecting AKI post-cisplatin. Additional studies are needed to determine whether raw biomarker values or biomarker values normalized to urinary creatinine are more strongly associated with patient outcomes.
Graphical abstract
A higher resolution version of the Graphical abstract is available as
Supplementary information
Enabling control over macromolecular ordering and the spatial distribution of structures formed via the mechanisms of molecular self-assembly is a challenge that could yield a range of new functional ...materials. In particular, using the self-assembly of minimalist peptides, to drive the incorporation of large complex molecules will allow a functionalization strategy for the next generation of biomaterial engineering. Here, for the first time, we show that co-assembly with increasing concentrations of a highly charged polysaccharide, fucoidan, the microscale ordering of Fmoc-FRGDF peptide fibrils and subsequent mechanical properties of the resultant hydrogel can be easily and effectively manipulated without disruption to the nanofibrillar structure of the assembly.
The thermoelectric properties of parallel arrays of organic molecules on a surface offer the potential for large-area, flexible, solution processed, energy harvesting thin-films, whose ...room-temperature transport properties are controlled by quantum interference (QI). Recently, it has been demonstrated that constructive QI (CQI) can be translated from single molecules to self-assembled monolayers (SAMs), boosting both electrical conductivities and Seebeck coefficients. However, these CQI-enhanced systems are limited by rigid coupling of the component molecules to metallic electrodes, preventing the introduction of additional layers which would be advantageous for their further development. These rigid couplings also limit our ability to suppress the transport of phonons through these systems, which could act to boost their thermoelectric output, without comprising on their impressive electronic features. Here, through a combined experimental and theoretical study, we show that cross-plane thermoelectricity in SAMs can be enhanced by incorporating extra molecular layers. We utilize a bottom-up approach to assemble multi-component thin-films that combine a rigid, highly conductive 'sticky'-linker, formed from alkynyl-functionalised anthracenes, and a 'slippery'-linker consisting of a functionalized metalloporphyrin. Starting from an anthracene-based SAM, we demonstrate that subsequent addition of either a porphyrin layer or a graphene layer increases the Seebeck coefficient, and addition of both porphyrin and graphene leads to a further boost in their Seebeck coefficients. This demonstration of Seebeck-enhanced multi-component SAMs is the first of its kind and presents a new strategy towards the design of thin-film thermoelectric materials.
Through an experimental and theoretical study, cross-plane thermoelectricity in Self-Assembled Monolayers (SAMs) was enhanced by adding extra molecular layers, presenting a new strategy towards the design of high thermoelectric materials.
It is known that the electrical conductance of single molecules can be controlled in a deterministic manner by chemically varying their anchor groups to external electrodes. Here, by employing ...synthetic methodologies to vary the terminal anchor groups around aromatic anthracene cores, and by forming self-assembled monolayers (SAMs) of the resulting molecules, we demonstrate that this method of control can be translated into cross-plane SAM-on-gold molecular films. The cross-plane conductance of SAMs formed from anthracene-based molecules with four different combinations of anchors are measured to differ by a factor of approximately 3 in agreement with theoretical predictions. We also demonstrate that the Seebeck coefficient of such films can be boosted by more than an order of magnitude by an appropriate choice of anchor groups and that both positive and negative Seebeck coefficients can be realised. This demonstration that the thermoelectric properties of SAMs are controlled by their anchor groups represents a critical step towards functional ultra-thin-film devices for future molecular-scale electronics.
It is known that the electrical conductance of single molecules can be controlled in a deterministic manner by chemically varying their anchor groups to external electrodes.
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