81 research outputs found
Mining Frequent Graph Patterns with Differential Privacy
Discovering frequent graph patterns in a graph database offers valuable
information in a variety of applications. However, if the graph dataset
contains sensitive data of individuals such as mobile phone-call graphs and
web-click graphs, releasing discovered frequent patterns may present a threat
to the privacy of individuals. {\em Differential privacy} has recently emerged
as the {\em de facto} standard for private data analysis due to its provable
privacy guarantee. In this paper we propose the first differentially private
algorithm for mining frequent graph patterns.
We first show that previous techniques on differentially private discovery of
frequent {\em itemsets} cannot apply in mining frequent graph patterns due to
the inherent complexity of handling structural information in graphs. We then
address this challenge by proposing a Markov Chain Monte Carlo (MCMC) sampling
based algorithm. Unlike previous work on frequent itemset mining, our
techniques do not rely on the output of a non-private mining algorithm.
Instead, we observe that both frequent graph pattern mining and the guarantee
of differential privacy can be unified into an MCMC sampling framework. In
addition, we establish the privacy and utility guarantee of our algorithm and
propose an efficient neighboring pattern counting technique as well.
Experimental results show that the proposed algorithm is able to output
frequent patterns with good precision
Sharing Social Network Data: Differentially Private Estimation of Exponential-Family Random Graph Models
Motivated by a real-life problem of sharing social network data that contain
sensitive personal information, we propose a novel approach to release and
analyze synthetic graphs in order to protect privacy of individual
relationships captured by the social network while maintaining the validity of
statistical results. A case study using a version of the Enron e-mail corpus
dataset demonstrates the application and usefulness of the proposed techniques
in solving the challenging problem of maintaining privacy \emph{and} supporting
open access to network data to ensure reproducibility of existing studies and
discovering new scientific insights that can be obtained by analyzing such
data. We use a simple yet effective randomized response mechanism to generate
synthetic networks under -edge differential privacy, and then use
likelihood based inference for missing data and Markov chain Monte Carlo
techniques to fit exponential-family random graph models to the generated
synthetic networks.Comment: Updated, 39 page
A Review on Finasteride: A 5-Alpha Reductase Inhibitors, its Mechanism, Facts and Benefits
This review gives the information about the Finasteride i.e. 5alpha-reductase inhibitor. Primarily finasteride isused to treat BPH i.e benign prostatic hyperplasia and male androgenetic alopecia. Five-alpha reductase inhibitors (5α-RIs) could stimulate male sexual dysfunction due to their effects on testosterone and DHT i.e. dihydrotestosterone. Some studies account insignificant or acceptable adverse effects, which decrease after a changeable period of time so that they do not require terminating finasteride administration. The 5alpha-reductase inhibitor finasteride blocks the conversion of TT to DHT i.e. testosterone to dihydrotestosterone (DHT), the androgen responsible for androgenetic alopecia i.e. male pattern hair loss. This paper presents a possible explanation of the Finasteride drug.
Keywords: Finasteride, 5alpha-reductase inhibitor, BPH, DHT, alopecia
Horizontal Transmission of Candida albicans and Evidence of a Vaccine Response in Mice Colonized with the Fungus
Disseminated candidiasis is the third leading nosocomial blood stream infection in the United States and is often fatal. We previously showed that disseminated candidiasis was preventable in normal mice by immunization with either a glycopeptide or a peptide synthetic vaccine, both of which were Candida albicans cell wall derived. A weakness of these studies is that, unlike humans, mice do not have a C. albicans GI flora and they lack Candida serum antibodies. We examined the influence of C. albicans GI tract colonization and serum antibodies on mouse vaccination responses to the peptide, Fba, derived from fructose bisphosphate aldolase which has cytosolic and cell wall distributions in the fungus. We evaluated the effect of live C. albicans in drinking water and antimicrobial agents on establishment of Candida colonization of the mouse GI tract. Body mass, C. albicans in feces, and fungal-specific serum antibodies were monitored longitudinally. Unexpectedly, C. albicans colonization occurred in mice that received only antibiotics in their drinking water, provided that the mice were housed in the same room as intentionally colonized mice. The fungal strain in unintentionally colonized mice appeared identical to the strain used for intentional GI-tract colonization. This is the first report of horizontal transmission and spontaneous C. albicans colonization in mice. Importantly, many Candida-colonized mice developed serum fungal-specific antibodies. Despite the GI-tract colonization and presence of serum antibodies, the animals made antibodies in response to the Fba immunogen. This mouse model has potential for elucidating C. albicans horizontal transmission and for exploring factors that induce host defense against disseminated candidiasis. Furthermore, a combined protracted GI-tract colonization with Candida and the possibility of serum antibody responses to the presence of the fungus makes this an attractive mouse model for testing the efficacy of vaccines designed to prevent human disseminated candidiasis
Midodrine and octreotide in the treatment of cirrhosis-related hemodynamic complications
fibrotic tissue altersportal blood flow and resistance, lead-ing to portal hypertension and activation of splanchnic arterial vasodilation.1 Vaso-dilation stimulates systemic and renal hemodynamic changes including renal sodium and water retention, upregulation of the renin–angiotensin–aldosterone sys-tem, and increased circulating catechola-mines.2,3 These changes lead to compli-cations of cirrhosis, including ascites and hepatorenal syndrome (HRS).4 Ascites is defined as the accumulation of fluid in the peritoneal cavity, which occurs in about 50 % of patients with compensated cirrhosis (Table 1).4,5 Rec-ommendations for treatment of ascites include dietary sodium restriction, di-uretics, and therapeutic paracentesis. As-cites may be resistant to diuretics or may be intractable due to diuretic-induced complications, which may result in re-fractory ascites. Therapeutic paracentesis is the treatment of choice for tense as-cites.4 Large-volume (>5 L) paracentesis can lead to paracentesis-induced circula-tory dysfunction (PICD), which is char-acterized by increases in renin activity and hyponatremia.5 In patients with cir-rhosis, ascites can be associated with re
FORMULATION AND EVALUATION OF TACROLIMUS LOADED TRANSFERSOMAL SUBLINGUAL FILMS FOR EFFICIENT MANAGEMENT OF ORGAN REJECTION: IN VITRO AND IN VIVO STUDY
Objective: Patients travailing with end-stage organ failure can benefit from life-saving treatment protocol called organ transplantation that also rallies eminence of life. Tacrolimus plays important role in maintaining the healthy status of the organ transplanted, but its widespread clinical application is constrained due to low oral bioavailability which can be the limiting factor for the reduction in life span of transplanted healthy organ.
Methods: To overcome the drawbacks of tacrolimus and to maximize its therapeutic efficiency, tacrolimus was formulated as transfersomes using thin film hydration method using soyalecithin and Tween-80,optimized by Central composite designs and characterized for Particle size, deformability index (DI), entrapment efficiency(EE%) and Zeta potential. The selected transfersome formulation was incorporated into sublingual films using Hydroxy Propyl Methyl Cellulose (HPMC) as film-forming polymer and Polyethylene Glycol (PEG-400) as Plasticizer. The physical characteristics (average weight, pH, uniformity of weight and thickness) of the prepared films were studied, in addition they were evaluated for the in vitro drug release, ex vivo permeation, Differential Scanning Calorimetry (DSC), Attenuated Reflectance Spectroscopy (ATR), Scanning Electronic Microscopy (SEM), stability and in vivo pharmacokinetics in rats to prove the effect of flexibility provided by vesicle formation through sublingual route for enhanced systemic availability of tacrolimus.
Results: Designed and optimized transfersomal vesicles showed the vesicle size of 139±2.1 nm with Deformability Index of 8.53±1.9%, Entrapment Efficiency of 86.66±1.2% and zeta potential of -23.6 mV respectively. Optimized Tacrolimus-loaded transfersomal vesicles (TAC-TFs) showed controlled release with more than 80±3.4% for extended period of time compared to pure drug Tacrolimus. The average weight of all prepared transfersomal sublingual film (TAC_TF_SL films), batches were found in the range of 55.8±1.45 to 94.2±1.42 mg with mean thickness in the range of 0.23+0.1 to 0.52±0.2 mm indicating uniform cast of respective batches. The surface pH was found to be in the range of 6.9 to 7.0 which was close to saliva pH.
Optimized transfersomal sublingual films as well as nanovesicular dispersions found to be followed Zero order, diffusion coupled with polymer relaxation. Ex vivo studies revealed the improved permeation of 6.51±0.04µg drug through sublingual mucosa than pure drug of 1.2±0.01 µg depicting the significant role of soyalecithin and edge activator in the formulations. Transfersomal sublingual films exhibited controlled release with higher plasma concentration of 9.16±2.34 µg/ml at Tmax of 1.29±1.51hr in comparison with 7.99±1.23 µg/ml at Tmax of 0.75±1.78hr (oral marketed dosage form Pengraf capsules) embarking the higher rate of controlled absorption after sublingual delivery of optimized sublingual films with significant increase in AUC of 129.87±2.40 μg/ml*hr when compared to AUC of marketed dosage form of 69.19 ±1.46 μg/ml*hr. In addition the absolute bioavailability of the drug following sublingual administration was found to be 70.77±2.92% in comparison with that after oral administration 40.60±2.34%.
Conclusion: Designed Tacrolimus loaded transfersomal sublingual films can be a promising carrier for delivering tacrolimus through sublingual route by enhancing drug bioavailability efficiently which can be a boon to organ transplanted patients
Receiver shape optimization for maximizing medium temperature CPC collector efficiency
Low optical-concentration solar thermal CPC collectors for process heat at 150-300. °C generally use thermal oil as the collector fluid. Thermal oils have low thermal conductivity and high viscosity, which leads to significant thermal resistance and hence reduced collector thermal efficiency. One way to minimize the thermal resistance is by having turbulent flow of the thermal oil within the receiver. For a given receiver area and mass flow rate of the fluid, this can be achieved by narrowing the flow passage but keeping the receiver area constant by adding external flat fins. In this paper a new receiver design for a compound parabolic concentrator is proposed which is a hybrid of a U-shaped tubular receiver and a bifacially irradiated flat receiver. To keep the receiver area constant, the fins are increased in width as the tube diameter is decreased. Its performance when enclosed in a glass vacuum tube and a CPC has been modelled. The transmission and absorption of solar energy, optical losses due to the receiver-reflector gap, heat transfer within the receiver, and the thermal losses have been modelled. Keeping the receiver area and fluid flow rate constant, the thermal resistance of the thermal oil flow within the receiver reduces when the flow passage is narrowed leading to increased thermal efficiency. On the other hand, the hybrid receiver has lower optical efficiency as compared to a tubular receiver due to its higher gap loss. Overall, the hybrid receiver has similar or better thermal efficiency than the tubular receiver. Thermal efficiency and effective thermal efficiency, which accounts for the pumping power penalty, shows that the performance improvement with thermal oil due to receiver shape optimization depends on the receiver area, concentration ratio, absorptivity and emissivity of the selective surface, the mass flow rate through the receiver and fluid temperature. Highest effective thermal efficiency is generally achieved in t
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