Gold(III) carboxylate species, stabilized by a κ3‐(N^C^C) ligand template, are presented herein. A η1‐AuIII‐C(O)‐OH species has been characterized under cryogenic conditions as a result of the ...nucleophilic attack of an ammonium hydroxide onto a dinuclear μ‐CO2‐κ3‐(N^C^C)AuIII precursor. Thermal decomposition for these species proceeds by an unusual decarbonylation process, in contrast to typical decarboxylation pathways observed in related metallocarboxylic acids.
Go for gold: Gold(III) carboxylates, stabilized by a κ3‐(N^C^C) ligand template, are presented. η1‐AuIII‐C(O)‐OH was obtained under cryogenic conditions as a result of the nucleophilic attack of an ammonium hydroxide onto a dinuclear μ‐CO2‐κ3‐(N^C^C)AuIII precursor. The thermal decomposition of these species proceeds by an unusual decarbonylation process.
Variations in rock strength act as a first‐order control on mountain landscapes. However, the transient topographic signal of basement exhumation has not been explored. We use model outputs to ...demonstrate the mobility of drainage divides in mountain ranges in response to the exhumation of basement rocks and the implications for the morphology of river catchments. The exhumation of harder rocks within a catchment reduces upstream channel steepness and erosion rates in contrast to neighboring catchments. The results are a shift in the orogen‐scale drainage divide toward the harder rocks, and the formation of range parallel longitudinal valleys as neighboring river networks capture the headwaters of catchments impacted by the harder lithology. Our model outputs provide a process explanation for the initiation of many longitudinal valleys in mountain ranges, and for the pinning of drainage divides on rocks of higher strength as seen the Central Pyrenees, Western Alps, or High Atlas.
Plain Language Summary
River networks that drain mountain ranges tend to have a fairly regular spacing along the range, and develop similar plan view shapes with a drainage divide at the crest of the range. However, when rocks of different hardness are exhumed to the surface, this simple pattern can be heavily modified. Large exposures of crystalline basement rocks often form the highest mountains and hence define the main drainage divide in many mountain chains such as the European Alps and the Pyrenees. Additionally, these massifs are often associated with river valleys that run parallel (longitudinal) to the mountain range. Our experiments use a numerical model that simulates the growth of mountain topography to demonstrate the processes responsible for the pinning of drainage divides and the formation of longitudinal valleys.
Key Points
We investigate the impact of exhuming high strength rocks in a mountainous landscape using numerical modeling and topographic analyses
Exhumation of harder rocks causes a reduction in upstream channel steepness and erosion rate and contrast with neighboring catchments
Landscape is rebalanced by drainage divide migration toward harder lithologies and formation of longitudinal trends in river valleys
Background Restricted motion during touch screen device use may contribute to wrist overuse injuries. Wrist radioulnar deviation and extension while using touch screen devices and digital or manual ...counterparts in male and female medical professional dominant and non-dominant hands were quantified to test the hypothesis that mobile touch screen device use reduces wrist motion. Methods An active motion detection system was used to record wrist motion of 12 participants while: tablet swiping and turning book pages; raising a cell and traditional phone to the ear; texting and typing; and entering numbers on a cell phone and manual calculator. Medial and lateral wrist surface range of motion (ROM) and minimum and maximum wrist radial-ulnar deviation and flexion-extension were quantified. Results Device, sex and handedness effects were determined (P<0.05). Maximum medial radial deviation and ROM were greater using a cell versus traditional phone. Maximum medial radial deviation was higher in the nondominant wrist during backward tablet swiping and while backward page turning versus tablet swiping. Maximum and minimum medial extension angles and ROM were greater while typing versus texting. Female nondominant hand maximum lateral extension and ROM were greater for typing versus texting and maximum medial extension and lateral extension ROM greater during manual versus cell phone calculator use with handedness combined. Maximum lateral extension and ROM were greater in females versus males using manual calculators. Conclusions Sex and handedness should instruct touch screen, digital and manual device design and use for optimal performance and injury prevention.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In view of reported associations between high adiposity, particularly in midlife and late-life dementia risk, we aimed to determine associations between body mass index (BMI), and BMI changes across ...adulthood and brain structure and pathology at age 69-71 years.
Four hundred sixty-five dementia-free participants from Insight 46, a sub-study of the British 1946 birth cohort, who had cross-sectional T1/FLAIR volumetric MRI, and florbetapir amyloid-PET imaging at age 69-71 years, were included in analyses. We quantified white matter hyperintensity volume (WMHV) using T1 and FLAIR 3D-MRI; β-amyloid (Aβ) positivity/negativity using a SUVR approach; and whole brain (WBV) and hippocampal volumes (HV) using 3D T1-MRI. We investigated the influence of BMI, and BMI changes at and between 36, 43, 53, 60-64, 69 and 71 years, on late-life WMHV, Aβ-status, WBV and mean HV. Analyses were repeated using overweight and obese status.
At no time-point was BMI, change in BMI or overweight/obese status associated with WMHV or WBV at age 69-71 years. Decreasing BMI in the 1-2 years before imaging was associated with an increased odds of being β-amyloid positive (OR 1.45, 95% confidence interval 1.09, 1.92). There were associations between being overweight and larger mean HV at ages 60-64 (β = 0.073 ml, 95% CI 0.009, 0.137), 69 (β = 0.076 ml, 95% CI 0.012, 0.140) and 71 years (β = 0.101 ml, 95% CI 0.037, 0.165). A similar, albeit weaker, trend was seen with obese status.
Using WMHV, β-amyloid status and brain volumes as indicators of brain health, we do not find evidence to explain reported associations between midlife obesity and late-life dementia risk. Declining BMI in later life may reflect preclinical Alzheimer's disease.
This review presents evidence of lead exposure and toxicity to wildlife and humans from spent shotgun and rifle ammunition and fishing weights, and the barriers and bridges to completing the ...transition to non-lead products. Despite the international availability of effective non-lead substitutes, and that more jurisdictions are adopting suitable policies and regulations, a broader transition to non-lead alternatives is prevented because resolution remains divided among disparate human user constituencies. Progress has occurred only where evidence is most compelling or where a responsible public authority with statutory powers has managed to change mindsets in the wider public interest. Arguments opposing lead bans are shown to lack validity. Differing national regulations impede progress, requiring analysis to achieve better regulation. Evidence that lead bans have reduced wildlife exposure should be used more to promote sustainable hunting and fishing. Evidence of the lead contribution from hunted game to human exposure should shape policy and regulation to end lead ammunition use. The Special Issue presents evidence that a transition to non-lead products is both warranted and feasible.
Because of the rapid increase in the world’s population, demand for forest products is increasing while large amounts of forest land are being lost or degraded. In addition, timber harvest is being ...restricted in many of the world’s natural forests. The use of plantations managed for timber production must increase to meet the world’s increasing demand for wood and fiber from this reduced land base. Concentrating timber production on the best-adapted sites will allow the world’s demands to be met on fewer acres. Intensive management of plantation forests is perhaps the only way to meet the increasing demand for forest products and still reserve large areas of native forests for conservation and preservation purposes. Maintaining long-term soil productivity in these intensively managed plantations is critical. The impacts of intensive management on soil quality and subsequent tree growth can be positive, neutral or negative; the direction and magnitude of the impact depends on the specific management practice soil physical, chemical and biological properties. In order to understand and predict the impacts of intensive management, the factors limiting productivity on each specific site must be understood.
Forest harvesting by itself tends to have minor impacts on soil quality and long-term site productivity. Compaction during timber harvesting can degrade the soil quality. However, tillage during site preparation can in most cases restore soil physical properties to pre-disturbance levels. Site preparation practices that remove large quantities of organic matter and surface soil can detrimentally impact soil quality, most notably on sandy soils. Intensive management practices such as fertilization can improve soil quality and increase site productivity by ameliorating factors limiting growth. The increased growth rates in intensively managed stands can indirectly improve soil quality by increasing organic matter. The increased production of coarse roots in intensively managed plantations is particularly important in this regard. These changes can lead to long-term improvement in soil quality and site productivity, especially on the degraded soils on which many forest plantations are established.
Based on the available data, intensive management can be practiced sustainably on many soils. Land classification systems are needed to identify soils that are suitable for intensive management. Site-specific management regimes must then be developed to insure that intensive management is practiced sustainably on these soils.
Species’ distributions are likely to be affected by a combination of environmental drivers. We used a data set of 11 million species occurrence records over the period 1970–2010 to assess changes in ...the frequency of occurrence of 673 macro‐moth species in Great Britain. Groups of species with different predicted sensitivities showed divergent trends, which we interpret in the context of land‐use and climatic changes. A diversity of responses was revealed: 260 moth species declined significantly, whereas 160 increased significantly. Overall, frequencies of occurrence declined, mirroring trends in less species‐rich, yet more intensively studied taxa. Geographically widespread species, which were predicted to be more sensitive to land use than to climate change, declined significantly in southern Britain, where the cover of urban and arable land has increased. Moths associated with low nitrogen and open environments (based on their larval host plant characteristics) declined most strongly, which is also consistent with a land‐use change explanation. Some moths that reach their northern (leading edge) range limit in southern Britain increased, whereas species restricted to northern Britain (trailing edge) declined significantly, consistent with a climate change explanation. Not all species of a given type behaved similarly, suggesting that complex interactions between species’ attributes and different combinations of environmental drivers determine frequency of occurrence changes. Synthesis and applications. Our findings are consistent with large‐scale responses to climatic and land‐use changes, with some species increasing and others decreasing. We suggest that land‐use change (e.g. habitat loss, nitrogen deposition) and climate change are both major drivers of moth biodiversity change, acting independently and in combination. Importantly, the diverse responses revealed in this species‐rich taxon show that multifaceted conservation strategies are needed to minimize negative biodiversity impacts of multiple environmental changes. We suggest that habitat protection, management and ecological restoration can mitigate combined impacts of land‐use change and climate change by providing environments that are suitable for existing populations and also enable species to shift their ranges.
Obstructive sleep apnoea (OSA) involves repeated breathing pauses during sleep due to upper airway obstruction. It causes excessive daytime sleepiness and has other health impacts. Continuous ...positive airway pressure (CPAP) therapy is effective first line treatment for moderate to severe OSA. Unfortunately, many patients have difficulty tolerating CPAP and pressure intolerance is probably an important contributing factor. Mandibular advancement devices (MAD) are an alternative to CPAP. They are worn in the mouth during sleep to reduce airway obstruction. There is some evidence that, when used in combination with CPAP, MADs improve airway anatomy enough to reduce the CPAP pressure required to treat OSA and that this combination therapy could improve CPAP adherence.
Consecutive patients starting on CPAP for moderate to severe OSA will be recruited at a regional NHS sleep service. Patients with high CPAP pressure requirements after initial titration, who satisfy all entry criteria and consent to participate, will undertake a 2-arm randomised crossover trial. The arms will be (i) standalone CPAP and (ii) CPAP + MAD therapy. Each arm will last 12 weeks, including 2 weeks acclimatisation. CPAP machines will be auto-titrating and with facility for data download, so the impact of MAD on CPAP pressure requirements and CPAP adherence can be easily measured. The primary outcome will be CPAP adherence. Secondary outcomes will include measures of OSA severity, patient-reported outcome measures including subjective daytime sleepiness, quality of life, and treatment preference at the trial exit and health service use. Cost-effectiveness analyses will be undertaken.
If the intervention is shown to be effective and cost-effective in improving adherence in this standard CPAP-eligible OSA patient population it would be relatively straightforward to introduce into existing OSA treatment pathways, within the wider NHS and more widely. Both MAD and CPAP are already used by sleep services so their combination would require only minor adjustments to existing clinical pathways. It would be straightforward to disseminate the results of the study through regional, national, and international respiratory meetings. The health economics analysis would provide cost-effectiveness data to inform service planning and clinical guidelines through policy briefing papers, including those by NICE and SIGN.
PAPMAT was registered with ISRCTN prior to recruitment beginning (ISRCTN Registry 2021): https://www.isrctn.com/ISRCTN33966032 . Registered on 17th November 2021.
Macrocyclic host molecules bound to electrode surfaces enable the complexation of catalytically active guests for molecular heterogeneous catalysis. We present a surface-anchored host–guest complex ...with the ability to electrochemically oxidize ammonia in both organic and aqueous solutions. With an adamantyl motif as the binding group on the backbone of the molecular catalyst Ru(bpy-NMe2)(tpada)(Cl)(PF6) (1) (where bpy-NMe2 is 4,4′-bis(dimethylamino)-2,2′-bipyridyl and tpada is 4′-(adamantan-1-yl)-2,2’:6′,2″-terpyridine), high binding constants with β-cyclodextrin were observed in solution (in DMSO-d 6:D2O (7:3), K 11 = 492 ± 21 M–1). The strong binding affinities were also transferred to a mesoporous ITO (mITO) surface functionalized with a phosphonated derivative of β-cyclodextrin. The newly designed catalyst (1) was compared to the previously reported naphthyl-substituted catalyst Ru(bpy-NMe2)(tpnp)(Cl)(PF6) (2) (where tpnp is 4′-(naphthalene-2-yl)-2,2’:6′,2″-terpyridine) for its stability during catalysis. Despite the insulating nature of the adamantyl substituent serving as the binding group, the stronger binding of this unit to the host-functionalized electrode and the resulting shorter distance between the catalytic active center and the surface led to better performance and higher stability. Both guests are able to oxidize ammonia in both organic and aqueous solutions, and the host-anchored electrode can be refunctionalized multiple times (>3) following the loss of the catalytic activity, without a reduction in performance. Guest 1 exhibits significantly higher stability in comparison to guest 2 toward basic conditions, which often constitutes a challenge for anchored molecular systems. Ammonia oxidation in water led to the selective formation of NO3 – with Faradaic efficiencies of up to 100%.
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