73 research outputs found
Thermoresponsive Nanogels Based on Different Polymeric Moieties for Biomedical Applications
Nanogels, or nanostructured hydrogels, are one of the most interesting materials in biomedical engineering. Nanogels are widely used in medical applications, such as in cancer therapy, targeted delivery of proteins, genes and DNAs, and scaffolds in tissue regeneration. One salient feature of nanogels is their tunable responsiveness to external stimuli. In this review, thermosensitive nanogels are discussed, with a focus on moieties in their chemical structure which are responsible for thermosensitivity. These thermosensitive moieties can be classified into four groups, namely, polymers bearing amide groups, ether groups, vinyl ether groups and hydrophilic polymers bearing hydrophobic groups. These novel thermoresponsive nanogels provide effective drug delivery systems and tissue regeneration constructs for treating patients in many clinical applications, such as targeted, sustained and controlled release
Wave energy and hot spots in Anzali port
Providing energy without unfavorable impacts on the environment is an important issue for many countries. Wave energy is one of the renewable resources with high potential and low impact on the environment, especially in coastal regions. The estimation of the wave characteristics is essential for selection of the appropriate location for wave energy exploitation. In this study, SWAN (Simulating WAves Nearshore) was used for modeling of the wave characteristics and to describe the existence and variability of wave energy in the southern part of the Caspian Sea. The model results were calibrated and verified using in-situ buoy measurements. Wave parameters were simulated and the annual wave energy was estimated in the study area. Then, high-energy spots were determined and the monthly average wave energy and seasonal variations of wave energy in the selected site were investigated. Furthermore, wave energy resource was characterized in terms of sea state parameters i.e. significant wave heights, wave periods and mean directions for selecting the most appropriate wave energy converters in the selected site. It was found that January and February, i.e. winter months, are the most energetic months and the main wave directions with the highest frequencies are northeast and northern-northeast in this site
Semi-classical Probe Strings on Giant Gravitons Backgrounds
In the first part of this paper we study two symmetries of the LLM
metric, both of which exchange black and white regions. One of them which can
be interpreted as the particle-hole symmetry is the symmetry of the whole
supergravity solution while the second one is just the symmetry of the metric
and changes the sign of the fivefrom flux. In the second part of the paper we
use closed string probes and their semi-classical analysis to compare the two
1/2 BPS deformations of , the smooth LLM geometry which
contains localized giant gravitons and the superstar case which is a solution
with naked singularity corresponding to smeared giants. We discuss the
realization of the symmetry in the semi-classical closed string probes
point of view.Comment: 29 pages, 6 .eps figures; v2: References adde
Thermoresponsive Nanogels Based on Different Polymeric Moieties for Biomedical Applications
Nanogels, or nanostructured hydrogels, are one of the most interesting materials in biomedical engineering. Nanogels are widely used in medical applications, such as in cancer therapy, targeted delivery of proteins, genes and DNAs, and scaffolds in tissue regeneration. One salient feature of nanogels is their tunable responsiveness to external stimuli. In this review, thermosensitive nanogels are discussed, with a focus on moieties in their chemical structure which are responsible for thermosensitivity. These thermosensitive moieties can be classified into four groups, namely, polymers bearing amide groups, ether groups, vinyl ether groups and hydrophilic polymers bearing hydrophobic groups. These novel thermoresponsive nanogels provide effective drug delivery systems and tissue regeneration constructs for treating patients in many clinical applications, such as targeted, sustained and controlled release
Complex Matrix Model and Fermion Phase Space for Bubbling AdS Geometries
We study a relation between droplet configurations in the bubbling AdS
geometries and a complex matrix model that describes the dynamics of a class of
chiral primary operators in dual N=4 super Yang Mills (SYM). We show rigorously
that a singlet holomorphic sector of the complex matrix model is equivalent to
a holomorphic part of two-dimensional free fermions, and establish an exact
correspondence between the singlet holomorphic sector of the complex matrix
model and one-dimensional free fermions. Based on this correspondence, we find
a relation of the singlet holomorphic operators of the complex matrix model to
the Wigner phase space distribution. By using this relation and the AdS/CFT
duality, we give a further evidence that the droplets in the bubbling AdS
geometries are identified with those in the phase space of the one-dimensional
fermions. We also show that the above correspondence actually maps the
operators of N=4 SYM corresponding to the (dual) giant gravitons to the droplet
configurations proposed in the literature.Comment: 27 pages, 6 figures, some clarification, typos corrected, published
versio
Fermions from Half-BPS Supergravity
We discuss collective coordinate quantization of the half-BPS geometries of
Lin, Lunin and Maldacena (hep-th/0409174). The LLM geometries are parameterized
by a single function on a plane. We treat this function as a collective
coordinate. We arrive at the collective coordinate action as well as path
integral measure by considering D3 branes in an arbitrary LLM geometry. The
resulting functional integral is shown, using known methods (hep-th/9309028),
to be the classical limit of a functional integral for free fermions in a
harmonic oscillator. The function gets identified with the classical limit
of the Wigner phase space distribution of the fermion theory which satisfies u
* u = u. The calculation shows how configuration space of supergravity becomes
a phase space (hence noncommutative) in the half-BPS sector. Our method sheds
new light on counting supersymmetric configurations in supergravity.Comment: 28 pages, 2 figures, epsf;(v3) eq. (3.3) clarified and notationally
simplified; version to appear in JHE
The efficacy of addition of dexmedetomidine to intrathecal bupivacaine in lower abdominal surgery under spinal anesthesia
Background: Spinal anesthesia is the common choice for anesthesia in lower abdomen surgery and intrathecal adjutants have gained popularity with the aim of prolonging the duration of block, quality of block and post operation pain control. The purpose of this study was to evaluate the effects of adding dexmedetomidine to hyperbaric bupivacaine in lower abdominal surgery under spinal anesthesia. The main outcomes were considered pain score, duration of analgesia, hemodynamic changes and adverse side effects like nausea and vomiting. Methods: This double-blind randomized clinical trial was conducted on one hundred patients between 18 to 65 years old scheduled for lower abdominal surgery. Fifty patients were randomly allocated to receive either 12.5mg hyperbaric bupivacaine (2.5cc) plus 5µgr dexmedetomidine (0.5cc) intrathecally while fifty patients received either 12.5mg hyperbaric bupivacaine (2.5cc) and 0.5cc Saline 0.9 intrathecally. Results: Vital sign parameters like heart rate, blood pressure and oxygen saturation levels were registered in the normal range in both groups. The average duration of the onset of pain (230±86 min) in bupivacaine group was significantly (p≤0.000) less than dexmedetomidine group (495±138 minutes). The severity of pain at all times in dexmedetomidine group was significantly (p<0.05) less than bupivacaine group. The severity of shivering and the number of patients who needed treatment for nausea and vomiting in dexmedetomedine group has been less in comparison to bupivacaine. Conclusion: We concluded that intrathecal dexmedetomidine increases the duration of analgesia and reduces postoperative pain without changes in the hemodynamic parameters and adverse side effects. It can be considered as an appropriate adjuvant to intrathecal local anesthetics for lower limb surgeries
Singularities and closed time-like curves in type IIB 1/2 BPS geometries
We study in detail the moduli space of solutions discovered in LLM relaxing
the constraint that guarantees the absence of singularities. The solutions fall
into three classes, non-singular, null-singular and time machines with a
time-like naked singularity. We study the general features of these metrics and
prove that there are actually just two generic classes of space-times - those
with null singularities are in the same class as the non-singular metrics.
AdS/CFT seems to provide a dual description only for the first of these two
types of space-time in terms of a unitary CFT indicating the possible existence
of a chronology protection mechanism for this class of geometries.Comment: 34 pages, 7 figures, LaTeX. References adde
Measuring universal health coverage based on an index of effective coverage of health services in 204 countries and territories, 1990–2019 : A systematic analysis for the Global Burden of Disease Study 2019
Background
Achieving universal health coverage (UHC) involves all people receiving the health services they need, of high quality, without experiencing financial hardship. Making progress towards UHC is a policy priority for both countries and global institutions, as highlighted by the agenda of the UN Sustainable Development Goals (SDGs) and WHO's Thirteenth General Programme of Work (GPW13). Measuring effective coverage at the health-system level is important for understanding whether health services are aligned with countries' health profiles and are of sufficient quality to produce health gains for populations of all ages.
Methods
Based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we assessed UHC effective coverage for 204 countries and territories from 1990 to 2019. Drawing from a measurement framework developed through WHO's GPW13 consultation, we mapped 23 effective coverage indicators to a matrix representing health service types (eg, promotion, prevention, and treatment) and five population-age groups spanning from reproductive and newborn to older adults (≥65 years). Effective coverage indicators were based on intervention coverage or outcome-based measures such as mortality-to-incidence ratios to approximate access to quality care; outcome-based measures were transformed to values on a scale of 0–100 based on the 2·5th and 97·5th percentile of location-year values. We constructed the UHC effective coverage index by weighting each effective coverage indicator relative to its associated potential health gains, as measured by disability-adjusted life-years for each location-year and population-age group. For three tests of validity (content, known-groups, and convergent), UHC effective coverage index performance was generally better than that of other UHC service coverage indices from WHO (ie, the current metric for SDG indicator 3.8.1 on UHC service coverage), the World Bank, and GBD 2017. We quantified frontiers of UHC effective coverage performance on the basis of pooled health spending per capita, representing UHC effective coverage index levels achieved in 2019 relative to country-level government health spending, prepaid private expenditures, and development assistance for health. To assess current trajectories towards the GPW13 UHC billion target—1 billion more people benefiting from UHC by 2023—we estimated additional population equivalents with UHC effective coverage from 2018 to 2023.
Findings
Globally, performance on the UHC effective coverage index improved from 45·8 (95% uncertainty interval 44·2–47·5) in 1990 to 60·3 (58·7–61·9) in 2019, yet country-level UHC effective coverage in 2019 still spanned from 95 or higher in Japan and Iceland to lower than 25 in Somalia and the Central African Republic. Since 2010, sub-Saharan Africa showed accelerated gains on the UHC effective coverage index (at an average increase of 2·6% [1·9–3·3] per year up to 2019); by contrast, most other GBD super-regions had slowed rates of progress in 2010–2019 relative to 1990–2010. Many countries showed lagging performance on effective coverage indicators for non-communicable diseases relative to those for communicable diseases and maternal and child health, despite non-communicable diseases accounting for a greater proportion of potential health gains in 2019, suggesting that many health systems are not keeping pace with the rising non-communicable disease burden and associated population health needs. In 2019, the UHC effective coverage index was associated with pooled health spending per capita (r=0·79), although countries across the development spectrum had much lower UHC effective coverage than is potentially achievable relative to their health spending. Under maximum efficiency of translating health spending into UHC effective coverage performance, countries would need to reach adjusted for purchasing power parity) in order to achieve 80 on the UHC effective coverage index. From 2018 to 2023, an estimated 388·9 million (358·6–421·3) more population equivalents would have UHC effective coverage, falling well short of the GPW13 target of 1 billion more people benefiting from UHC during this time. Current projections point to an estimated 3·1 billion (3·0–3·2) population equivalents still lacking UHC effective coverage in 2023, with nearly a third (968·1 million [903·5–1040·3]) residing in south Asia.
Interpretation
The present study demonstrates the utility of measuring effective coverage and its role in supporting improved health outcomes for all people—the ultimate goal of UHC and its achievement. Global ambitions to accelerate progress on UHC service coverage are increasingly unlikely unless concerted action on non-communicable diseases occurs and countries can better translate health spending into improved performance. Focusing on effective coverage and accounting for the world's evolving health needs lays the groundwork for better understanding how close—or how far—all populations are in benefiting from UHC
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