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"Williams, A G"
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Graphene-Based Materials in Dental Applications: Antibacterial, Biocompatible, and Bone Regenerative Properties
Graphene-based materials have been shown to have advantageous properties in biomedical and dental applications due to their high mechanical, physiochemical, antibacterial, and stem cell differentiating properties. Although graphene-based materials have displayed appropriate biocompatible properties when used in implant materials for orthopedic applications, little research has been performed to specifically test the biocompatibility of graphene for dental applications. The oral environment, compared to the body, varies greatly and must be considered when evaluating biocompatibility requirements for dental applications. This review will discuss in vitro and in vivo studies that assess graphene’s cytotoxicity, antibacterial properties, and cell differentiation ability to evaluate the overall biocompatibility of graphene-based materials for dental applications. Particle shape, size, and concentration were found to be major factors that affected overall biocompatibility of graphene.
Journal Article
الوعي التام : دليل عملي للعثور على الطمأنينة في عالم مجنون
یكشف هذا الكتاب مجموعة من الممارسات البسيطة والفعالة التي يمكنك إدراجها في حياتك اليومية لمساعدتك على الخروج من دائرة القلق والتوتر والتعاسة والإرهاق. وهو يساعدك على تعزيز متعة حياة صادقة ذلك : النوع من السعادة الذي يتغلغل في أعماقك ويتيح لك مواجهة أسوأ ما تلقي به الحياة في طريقك بشجاعة. ويستند هذا الكتاب إلى العلاج المعرفي القائم على الوعي التام. إن العلاج المعرفي القائم على الوعي التام الذي شارك في تطويره البروفيسور مارك ويليامز من جامعة أوكسفورد، ينصح به المعهد الوطني للتفوق الصحي والإكلينيكي في المملكة المتحدة، ولا يقل فاعلية عن الأدوية لتجنب الاكتئاب، ولكنه، بالمثل، ينجح أيضا مع بقيتنا الذين لا يعانون الاكتئاب ولكنهم يكافحون لمواكبة المتطلبات المستمرة للعالم الحديث ومن خلال استثمار بضع دقائق فقط كل يوم، يمكنك تعلم تأملات الوعي التام البسيطة التي تعد جوهر العلاج المعرفي القائم على الوعي التام. وسوف تندهش من مدى السرعة التي يمكنك بها استعادة السيطرة والقدرة على الاستمتاع بالحياة مرة أخرى.
Book
On the use of radon for quantifying the effects of atmospheric stability on urban emissions
Radon is increasingly being used as a tool for quantifying stability influences on urban pollutant concentrations. Bulk radon gradients are ideal for this purpose, since the vertical differencing substantially removes contributions from processes on timescales greater than diurnal and (assuming a constant radon source) gradients are directly related to the intensity of nocturnal mixing. More commonly, however, radon measurements are available only at a single height. In this study we argue that single-height radon observations should not be used quantitatively as an indicator of atmospheric stability without prior conditioning of the time series to remove contributions from larger-scale \"non-local\" processes. We outline a simple technique to obtain an approximation of the diurnal radon gradient signal from a single-height measurement time series, and use it to derive a four category classification scheme for atmospheric stability on a \"whole night\" basis. A selection of climatological and pollution observations in the Sydney region are then subdivided according to the radon-based scheme on an annual and seasonal basis. We compare the radon-based scheme against a commonly used Pasquill–Gifford (P–G) type stability classification and reveal that the most stable category in the P–G scheme is less selective of the strongly stable nights than the radon-based scheme; this lead to significant underestimation of pollutant concentrations on the most stable nights by the P–G scheme. Lastly, we applied the radon-based classification scheme to mixing height estimates calculated from the diurnal radon accumulation time series, which provided insight to the range of nocturnal mixing depths expected at the site for each of the stability classes.
Journal Article
Bulk Mixing and Decoupling of the Nocturnal Stable Boundary Layer Characterized Using a Ubiquitous Natural Tracer
Vertical mixing of the nocturnal stable boundary layer (SBL) over a complex land surface is investigated for a range of stabilities, using a decoupling index (
0
<
D
r
b
<
1
) based on the 2–50 m bulk gradient of the ubiquitous natural trace gas radon-222. The relationship between
D
r
b
and the bulk Richardson number (
R
i
b
) exhibits three broad regions: (1) a well-mixed region (
D
r
b
≈
0.05
) in weakly stable conditions (
R
i
b
<
0.03
); (2) a steeply increasing region (
0.05
<
D
r
b
<
0.9
) for “transitional” stabilities (
0.03
<
R
i
b
<
1
); and (3) a decoupled region (
D
r
b
≈
0.9
–1.0) in very stable conditions (
R
i
b
>
1
).
D
r
b
exhibits a large variability within individual
R
i
b
bins, however, due to a range of competing processes influencing bulk mixing under different conditions. To explore these processes in
R
i
b
–
D
r
b
space, we perform a bivariate analysis of the bulk thermodynamic gradients, various indicators of external influences, and key turbulence quantities at 10 and 50 m. Strong and consistent patterns are found, and five distinct regions in
R
i
b
–
D
r
b
space are identified and associated with archetypal stable boundary-layer regimes. Results demonstrate that the introduction of a scalar decoupling index yields valuable information about turbulent mixing in the SBL that cannot be gained directly from a single bulk thermodynamic stability parameter. A significant part of the high variability observed in turbulence statistics during very stable conditions is attributable to changes in the degree of decoupling of the SBL from the residual layer above. When examined in
R
i
b
–
D
r
b
space, it is seen that very different turbulence regimes can occur for the same value of
R
i
b
, depending on the particular combination of values for the bulk temperature gradient and wind shear, together with external factors. Extremely low turbulent variances and fluxes are found at 50 m height when
R
i
b
>
1
and
D
r
b
≈
1
(fully decoupled). These “quiescent” cases tend to occur when geostrophic forcing is very weak and subsidence is present, but are not associated with the largest bulk temperature gradients. Humidity and net radiation data indicate the presence of low cloud, patchy fog or dew, any of which may aid decoupling in these cases by preventing temperature gradients from increasing sufficiently to favour gravity wave activity. The largest temperature gradients in our dataset are actually associated with smaller values of the decoupling index (
D
r
b
<
0.7
), indicating the presence of mixing. Strong evidence is seen from enhanced turbulence levels, fluxes and submeso activity at 50 m, as well as high temperature variances and heat flux intermittencies at 10 m, suggesting this region of the
R
i
b
–
D
r
b
distribution can be identified as a top-down mixing regime. This may indicate an important role for gravity waves and other wave-like phenomena in providing the energy required for sporadic mixing at this complex terrain site.
Journal Article
The rising tide of opioid use and abuse: the role of the anesthesiologist
Opioid use has risen dramatically in the past three decades. In the USA, opioid overdose has become a leading cause of unintentional death, surpassing motor vehicle accidents. A patient’s first exposure to opioids may be during the perioperative period, a time where anesthesiologists have a significant role in pain management. Almost all patients in the USA receive opioids during a surgical encounter. Opioids have many undesirable side effects, including potential for misuse, or opioid use disorder. Anesthesiologists and surgeons employ several methods to decrease unnecessary opioid use, opioid-related adverse events, and side effects in the perioperative period. Multimodal analgesia, enhanced recovery pathways, and regional anesthesia are key tools as we work towards optimal opioid stewardship and the ideal of effective analgesia without undesirable sequelae.
Journal Article
Characterising terrestrial influences on Antarctic air masses using Radon-222 measurements at King George Island
We report on one year of high-precision direct hourly radon observations at King Sejong Station (King George Island) beginning in February 2013. Findings are compared with historic and ongoing radon measurements from other Antarctic sites. Monthly median concentrations reduced from 72 mBq m−3 in late-summer to 44 mBq m−3 in late winter and early spring. Monthly 10th percentiles, ranging from 29 to 49 mBq m−3, were typical of oceanic baseline values. Diurnal cycles were rarely evident and local influences were minor, consistent with regional radon flux estimates one tenth of the global average for ice-free land. The predominant fetch region for terrestrially influenced air masses was South America (47–53° S), with minor influences also attributed to aged Australian air masses and local sources. Plume dilution factors of 2.8–4.0 were estimated for the most terrestrially influenced (South American) air masses, and a seasonal cycle in terrestrial influence on tropospheric air descending at the pole was identified and characterised.
Journal Article
Surface-to-mountaintop transport characterised by radon observations at the Jungfraujoch
Atmospheric composition measurements at Jungfraujoch are affected intermittently by boundary-layer air which is brought to the station by processes including thermally driven (anabatic) mountain winds. Using observations of radon-222, and a new objective analysis method, we quantify the land-surface influence at Jungfraujoch hour by hour and detect the presence of anabatic winds on a daily basis. During 2010–2011, anabatic winds occurred on 40% of days, but only from April to September. Anabatic wind days were associated with warmer air temperatures over a large fraction of Europe and with a shift in air-mass properties, even when comparing days with a similar mean radon concentration. Excluding days with anabatic winds, however, did not lead to a better definition of the unperturbed aerosol background than a definition based on radon alone. This implies that a radon threshold reliably excludes local influences from both anabatic and non-anabatic vertical-transport processes.
Journal Article
Wet deposition in shallow convection over the Southern Ocean
Southern Ocean (SO) air is amongst the most pristine on Earth, particularly during winter. Historically, there has been a focus on biogenic sources as an explanation for the seasonal cycle in cloud condensation nuclei concentrations (
N
CCN
).
N
CCN
is also sensitive to the strength of sink terms, although the magnitude of this term varies considerably. Wet deposition, a process encompassing coalescence scavenging (drizzle formation), is one such process that may be especially relevant over the SO. Using a boundary layer cloud climatology,
N
CCN
and precipitation observations from Kennaook/Cape Grim Observatory (CGO), we find a statistically significant difference in
N
CCN
between when the upwind meteorology is dominated by open mesoscale cellular convection (MCC) and closed MCC. When open MCC is dominant, a lower median
N
CCN
(69 cm
−3
) is found compared to when closed MCC (89 cm
−3
) is dominant. Open MCC is found to precipitate more heavily (1.72 mm day
−1
) and more frequently (16.7% of the time) than closed MCC (0.29 mm day
−1
, 4.5%). These relationships are observed to hold across the seasonal cycle with maximum
N
CCN
and minimum precipitation observed during Austral summer (DJF). Furthermore, the observed MCC morphology strongly depends on meteorological conditions. The relationship between
N
CCN
and precipitation can be further examined across a diurnal cycle during the summer season. Although there was again a negative relationship between precipitation and
N
CCN
, the precipitation cycle was out of phase with the
N
CCN
cycle, leading it by ~3 hours, suggesting other factors, specifically the meteorology play a primary role in influencing precipitation.
Journal Article