4,769 research outputs found
Cefazolin Prophylaxis for Total Joint Arthroplasty: Obese Patients Are Frequently Underdosed and at Increased Risk of Periprosthetic Joint Infection
Background
One of the most effective prophylactic strategies against periprosthetic joint infection (PJI) is administration of perioperative antibiotics. Many orthopedic surgeons are unaware of the weight-based dosing protocol for cefazolin. This study aimed at elucidating what proportion of patients receiving cefazolin prophylaxis are underdosed and whether this increases the risk of PJI.
Methods
A retrospective study of 17,393 primary total joint arthroplasties receiving cefazolin as perioperative prophylaxis from 2005 to 2017 was performed. Patients were stratified into 2 groups (underdosed and adequately dosed) based on patient weight and antibiotic dosage. Patients who developed PJI within 1 year following index procedure were identified. A bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify risk factors for PJI.
Results
The majority of patients weighing greater than 120 kg (95.9%, 944/984) were underdosed. Underdosed patients had a higher rate of PJI at 1 year compared with adequately dosed patients (1.51% vs 0.86%, P = .002). Patients weighing greater than 120 kg had higher 1-year PJI rate than patients weighing less than 120 kg (3.25% vs 0.83%, P < .001). Patients who were underdosed (odds ratio, 1.665; P = .006) with greater comorbidities (odds ratio, 1.259; P < .001) were more likely to develop PJI at 1 year.
Conclusion
Cefazolin underdosing is common, especially for patients weighing more than 120 kg. Our study reports that underdosed patients were more likely to develop PJI. Orthopedic surgeons should pay attention to the weight-based dosing of antibiotics in the perioperative period to avoid increasing risk of PJI
âLoobâ and âLabasâ: Spatial Constructions of Safety and Risk Amid the COVID-19 Pandemic in the Philippines
This article argues that local constructions of risky and safe spaces, as articulated by the notions âloobâ (inside) and âlabasâ (outside), informed popular and political responses to the COVID-19 pandemic in the Philippines, leading to an overemphasis on staying at home and, conversely, a general avoidance or fear of outdoor spaces that was at times reinforced by public health authorities. Practices and policies related to the pandemic response rendered this binary opposition between âloobâ and âlabasâ visible, from regulations concerning the use of personal protective equipment to restrictions of access to outdoor spaces. While this emergent form of bodily proxemics was contested and negotiated over time, its tenacity throughout the pandemic underscores the importance of understanding how people spatialize risk in times of health crises
Effect of impurity trapping on the capacitanceâvoltage characteristics of nâGaAs/NâAlGaAs heterojunctions
We have studied the capacitance-voltage (C- V) characteristics of Schottky barriers on inverted nGaAs/ N-AIGaAs and normal N-AIGaAs/n-GaAs heterojunctions. Impurities introduced during film growth produced a negative sheet charge of 6.0 X 10 II cm -2 at the interface of the inverted n-GaAs/N-AIGaAs heterojunction. The effectiveness of GaAs quantum wells in trapping these impurities was investigated. GaAs quantum wells 20 A wide were placed in intervals of 2500 A for the first 0.75 pm of the AIGaAs layer; in the last 0.25 pm, the periodicity of the quantum wells was progressively decreased by half with the last quantum well placed at about 160 A from the GaAs/ AIGaAs interface. The resulting measured interface charge concentration of 4.4 X 1010 cm -2 is more than a magnitude lower than measured before the use of the quantum wells and is essentially at the limit of the accuracy of the C-V technique for this structure
Splice Strength of Epoxy-Coated High Relative Rib Area Bars
The effect of epoxy coating on the splice strength of high relative rib area bars with and without confining transverse reinforcement is described. Test results for 47 beam splice specimens containing No. 5, No. 8, or No. 11 (16, 25 or 36 mm) bars with relative rib areas ranging from 0.101 to 0.141 and seven deformation patterns are included in the analysis. Twenty seven of the 47 beam splice tests are reported for the first time. Average coating thickness ranged from 7.1 to 16.8 mils (0.18 to 0.43 mm). Fortythree specimens were bottom-cast and four were top-cast. The test results for the high relative rib area bars are combined with 44 previous splice tests using conventional bars. Epoxy coating was found to have a much less detrimental effect on splice strength for high relative rib area bars than for conventional bars. The average splice strength ratio of coated to uncoated bars C/U is 0.89, compared to 0.74 for conventional reinforcement. C!U is approximately the same for splices with and without transverse reinforcement. The test results of the current study indicate that the development length modification factor required by the ACI Building Code (318-95) and the AASHTO Bridge Specifications (1992) can be reduced from 1.5 to 1.2 for epoxy-coated high relative rib bars
The tools of policy formulation: an introduction
What techniques or means do public policymakers use in their attempts to achieve policy goals? The roles of what may be termed policy instruments, tools and methods (Howlett 2011, p. 22) have attracted a great deal of attention. It is generally accepted that policy tools and instruments exist at all stages of the policy process (Howlett 2011, p. 22), ranging from policy formulation through to ex post evaluation (Dunn 2004). But in the public policy literature, much of the debate has focused on instruments for implementing agreed policy objectives, such as regulations, subsidies, taxes and voluntary agreements (Hood 1983; Hood and Margetts 2007; Salamon 2002). Recently, a second category of implementing instruments has been identified: procedural tools (Howlett 2000). These include education, training, provision of information and public hearings. These are procedural in the sense that they seek to affect outcomes indirectly through manipulating policy processes. The manner in which both types of instruments are selected and deployed aims to change the substance, effects and outcomes of policy, by sending signals about what is to be achieved and how government is likely to respond to target groups
The Biermann Battery in Cosmological MHD Simulations of Population III Star Formation
We report the results of the first self-consistent three-dimensional adaptive
mesh refinement magnetohydrodynamical simulations of Population III star
formation including the Biermann Battery effect. We find that the Population
III stars formed including this effect are both qualitatively and
quantitatively similar to those from hydrodynamics-only (non-MHD) cosmological
simulations. We observe peak magnetic fields of ~10^-9 G in the center of our
star-forming halo at z ~ 17.55. The magnetic fields created by the Biermann
Battery effect are predominantly formed early in the evolution of the
primordial halo at low density and large spatial scales, and then grow through
compression and by shear flows. The fields seen in this calculation are never
large enough to be dynamically important (with beta >= 10^{15} at all times),
and should be considered the minimum possible fields in existence during
Population III star formation, and may be seed fields for the stellar dynamo or
the magnetorotational instability at higher densities and smaller spatial
scales.Comment: 4 pages, 3 figures; Submitted to the Astrophysical Journal Letters.
Comments welcome. Typo found (and fixed) in equation
The microwave spectrum, structure, and large amplitude motions of the methylacetyleneâ SO2 complex
Rotational spectra of five isotopomers of the methylacetyleneâ
SO2 (MAâ
SO2) van der Waals complex have been observed with a Fourier transform microwave spectrometer. Each species showed two sets of rotational transitions, one associated with the A (m=0) and the other with the E (m=±1) methyl group internal rotation states. The rotational transitions of the isotopomers with Sâ16O2 and the doubly substituted Sâ18O2 also showed inversion splitting ranging from tens of kHz to a few MHz. This splitting was absent in the Sâ16Oâ18O isotopomers. The spectra of these species have been assigned and fit, yielding rotational constants, which allowed a complete determination of the structure of the complex. The SO2 was found to sit above the carbonâcarbon triple bond, with one of the SâO bonds roughly parallel to the symmetry axis of methylacetylene. The centersâofâmass distance between the two monomers was determined to be 3.382(10) Ă
. The center frequencies of the inversion doublets (or quartets) were used in a fit of both the A and the E transitions; the barrier hindering the internal rotation of the methyl group was determined to be 62.8(5) cmâ1. Based on the dependence of the inversion splitting on the transition dipole direction and isotopic substitution, the inversion motion was identified as an ââin planeââ wagging of the SO2 relative to methylacetylene. A pure inversion splitting of 3.11 MHz (free from rotation) was extracted from the Aâstate spectrum of the normal species, from which an inversion barrier height of about 63 cmâ1 was estimated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69904/2/JCPSA6-101-8-6512-1.pd
Modernizing Frontier Chemical Transformations of Young Peopleâs Minds and Bodies in Puerto Princesa
Palawan is a land of promise, and of paradox.
On maps, it appears on the edge of the Philippines, isolated. Indeed,
it is a kind of last frontier. Its population remained tiny for centuries,
the government offering homestead land in the 1950s practically for
free to attract migrants from outside. The Palawan State University was
established by law in 1965, but did not become operational until 1972.
A commercial airport did not exist until the 1980s, and for many years,
flights were limited.
Yet Palawan is one of the oldest sites of human habitation in the
Philippines with the famous Tabon Cave human fossils. The oldest bone
fragment here has been dated to be about 47,000 years. We know, too,
that trade with China goes back several centuries.
Today, Palawan seems to be making up for lost time with new commercial
investments pouring in at breakneck speed. In particular, outsiders have
rediscovered its potentials around logging, mining, fisheries, and tourism.
This has caused concern among individuals and civil society organizations
who want sustainable development, and see the commercial developments
mainly as extractive, not just of natural resources but of the human.
Thereâs very cheap labor available. And when potential investors marvel
about cheap land, theyâre actually talking about displacing earlier settlers,
including indigenous people, from their lands.
A subtle but still insidious aspect of the exploitation of human resources
is a transformation of the very concept of human development. Using
the rhetoric of modernity, residents in Palawan are reorienting the way
they view themselves as well as their families and friends. The value of a
human being now hinges on how they look, and the desired appearance
is defined from the outside, as we see in this anthology of research reports
coming from the Chemical Youth project of the University of Amsterdam
and the University of the Philippines Diliman.
We read about the importance of fair skin as a projection of cleanliness,
of high social status (meaning someone not engaged in manual labor
and therefore not exposed to the sun). We read of how âfemininityâ is
defined around body contours, and cosmetics, and how hormones are
used by male-to-female transgenders. We go beyond the visual, reading
about the importance of controlling or enhancing body odors among
tour guides, who interestingly are especially concerned about the bad
odor management of their foreign customers, using car perfumes to keep
their work manageable and we learn how difficult it is for security guards
to stay alert during their long shifts. Energy drinks and cigarettes help
them perform their duties.
All these transformations through what the French philosopher and
historian Michel Foucault has called âtechnologies of the selfâ are
as paradoxical as Palawan. On the surface, the productsâwhich are
technologiesâseem to be mainly in the realm of the self but are, in
reality, pushed, through marketing, from the outside, in contexts of
inequality and exploitative labour relations. Personal aspirations are not
personal but are for predefined standards of modernity, related to work-related demands and expectations. The self must be made presentable to
the tourist, to the customers in malls, and to those who may threaten the
properties that young people protect.
It is not surprising that these transformations become problematic for
the âself.â The skin whiteners, the hormones, the body deodorants, and
the energy drinks are expensive and can distort budgetary priorities. The
money for tonic drinks, for example, could well go into more nutritious
food.
The tragedy, too, many of the products used are of doubtful safety and
efficacy. Even the energy drinks have much too high levels of caffeine that
can cause cardiac palpitations. Cosmetics and the skin whiteners imported
from China and unregistered with the Food and Drug Administration
may contain toxic chemicals like mercury. But even registered skin
whiteners can be problematic, their so-called âskin-whitening effectâ
coming about because they take away the upper layers of the skin, leaving
behind a red glow (seen as âwhiteningâ) which is actually inflammation.
The whitened skin fails to protect against the sun, leading to adverse
effects such as black spots.
Ultimately though, the problems come with the very definition of the
self. As the reports show, young people use the chemicals with some
ambivalence, knowing how expensive they are and experiencing some
of the undesirable side effects. There is, too, doubt about whether what
theyâre doing is indeed âgood,â captured by how IP women will put on
cosmetics only when theyâre away from home and about to go to work.
The cosmetics have to be removed before they return home because they
are not socially acceptable.
The research reports are not for Palawan alone. It must make us
more critical and discerning as we revisit concepts of development
and exploitation, modernity and tradition, self and community. The
chemicals, in many ways, are like the products used in precolonial barter
trade. For the Chinese, the beeswax and the sea cucumbers, for the
inhabitants of Palawan the ceramics, represented faraway lands. To have
those products gave prestige.
Today, the skin whiteners and tonic drinks and other chemicals described
in this anthology represent modernity with promises of not just of a more
attractive self, but of better jobs, a better life.
We are proud to have worked with the Palawan State University, and
the people of Palawan, to gather powerful narratives that will now challenge the outside, the purveyors of modernity, to be more critical
and discerning, the chemicals now to be seen not just as stuff applied to
the biological body, but as powerful shapers of social bodies
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