A novel multi-stage distributed authentication scheme for smart meter communication.

Smart meters have ensured effective end-user energy consumption data management and helping the power companies towards network operation efficiency. However, recent studies highlighted that cyber adversaries may launch attacks on smart meters that can cause data availability, integrity, and confidentiality issues both at the consumer side or at a network operator's end. Therefore, research on smart meter data security has been attributed as one of the top priorities to ensure the safety and reliability of the critical energy system infrastructure. Authentication is one of the basic building blocks of any secure system. Numerous authentication schemes have been proposed for the smart grid, but most of these methods are applicable for two party communication. In this article, we propose a distributed, dynamic multistage authenticated key agreement scheme for smart meter communication. The proposed scheme provides secure authentication between smart meter, NAN gateway, and SCADA energy center in a distributed manner. Through rigorous cryptanalysis we have proved that the proposed scheme resist replay attack, insider attack, impersonation attack and man-in-the-middle attack. Also, it provides perfect forward secrecy, device anonymity and data confidentiality. The proposed scheme security is formally proved in the CK-model and, using BAN logic, it is proved that the scheme creates a secure session between the communication participants. The proposed scheme is simulated using the AVISPA tool and verified the safety against all active attacks. Further, efficiency analysis of the scheme has been made by considering its computation, communication, and functional costs. The computed results are compared with other related schemes. From these analysis results, it is proved that the proposed scheme is robust and secure when compared to other schemes.

Association of Wnt9B rs1530364 and Wnt5A rs566926 Gene Polymorphisms with Nonsyndromic Cleft lip and Palate in South Indian Population using Deoxyribonucleic Acid Sequencing.

CONTEXT: Nonsyndromic cleft lip with or without cleft palate (CL/CP) is a common congenital facial malformation without any other structural or developmental abnormalities. AIMS AND OBJECTIVES: To test the association of Wnt9B rs1530364 and Wnt5A rs566926 gene variants with the nonsyndromic CL/CP patients in South Indian population. METHODS: Deoxyribonucleic acid (DNA) samples of 25 subjects with nonsyndromic cleft lip and palate (NSCLP) and 25 unrelated controls collected from the department were used for the study. Group A: DNA samples of 25 subjects NSCLP (P1-P25). Group B: DNA samples of 25 unrelated controls (C1-C25). The extracted DNA samples were subjected to polymerase chain reaction, and later, these amplified products were subjected to DNA sequencing. Results were documented in the form of electropherograms. RESULTS: The results indicated that there is a strong association between the presence of Wnt9B rs1530364 gene with the incidence of NSCLP. This study also suggests that the likelihood of NSCLP is higher in subjects having CC (P = 0.02) genotype for Wnt9B gene variant rs1530364. CONCLUSION: We can conclude that Wnt9B gene variant rs1530364 can be considered as genetic marker for NSCLP for our population.

Asymmetric confinement for defining outgrowth directionality.

Directional connectivity is required to develop accurate in vitro models of the nervous system. This research investigated the interaction of murine neuronal outgrowths with asymmetric microstructured geometries to provide insights into the mechanisms governing unidirectional outgrowth bias. The structures were designed using edge-guidance and critical turning angle principles to study different prohibitive to permissive edge-guidance ratios. The different structures enable outgrowth in the permissive direction, while reducing outgrowth in the prohibitive direction. Outgrowth bias was probabilistic in nature, requiring multiple structures for effective unidirectional bias in primary hippocampal cultures at 14 days in vitro. Arrowhead structures with acute posterior corners were optimal, enabling 100% unidirectional outgrowth bias by virtue of re-routing and delay effects.

Serial integration of Dean-structured sample cores with linear inertial focussing for enhanced particle and cell sorting.

In this contribution, a channel aspect ratio of >2 was used to access high velocity regimes to provide confined sample cores by Dean focussing in advance of linear inertial focussing. This produces a singular separation origin with a mirrored transport path for efficient particle and blood cell sorting, while also increasing the spatial resolution for multiscale sorting.

Long-term maintenance of a microfluidic 3D human liver sinusoid.

The development of long-term human organotypic liver-on-a-chip models for successful prediction of toxic response is one of the most important and urgent goals of the NIH/DARPA's initiative to replicate and replace chronic and acute drug testing in animals. For this purpose, we developed a microfluidic chip that consists of two microfluidic chambers separated by a porous membrane. The aim of this communication is to demonstrate the recapitulation of a liver sinusoid-on-a-chip, using human cells only for a period of 28 days. Using a step-by-step method for building a 3D microtissue on-a-chip, we demonstrate that an organotypic in vitro model that reassembles the liver sinusoid microarchitecture can be maintained successfully for a period of 28 days. In addition, higher albumin synthesis (synthetic) and urea excretion (detoxification) were observed under flow compared to static cultures. This human liver-on-a-chip should be further evaluated in drug-related studies.

Long-term coculture strategies for primary hepatocytes and liver sinusoidal endothelial cells.

Hepatocytes and their in vitro models are essential tools for preclinical screening studies for drugs that affect the liver. Most of the current models primarily focus on hepatocytes alone and lack the contribution of non-parenchymal cells (NPCs), which are significant through both molecular and the response of the NPCs themselves. Models that incorporate NPCs alongside hepatocytes hold the power to enable more realistic recapitulation and elucidation of cell interactions and cumulative drug response. Hepatocytes and liver sinusoidal endothelial cells (LSECs) account for ∼ 80% of the liver mass where the LSECs line the walls of blood vessels, and act as a barrier between hepatocytes and blood. Culturing LSECs with hepatocytes to generate multicellular physiologically relevant in vitro liver models has been a major hurdle since LSECs lose their phenotype rapidly after isolation. To this end, we describe the application of collagen gel (1) in a sandwich and (2) as an intervening extracellular matrix layer to coculture hepatocytes with LSECs for extended periods. These coculture configurations provide environments wherein hepatocyte and LSECs, through cell-cell contacts and/or secretion factors, lead to enhanced function and stability of the cocultures. Our results show that in these configurations, hepatocytes and LSECs maintained their phenotypes when cultured together as a mixture, and showed stable secretion and metabolic activity for up to 4 weeks. Immunostaining for sinusoidal endothelial 1 (SE-1) antibody demonstrated retention of LSEC phenotype during the culture period. In addition, LSECs cultured alone maintained high viability and SE-1 expression when cultured within a collagen sandwich configuration up to 4 weeks. Albumin production of the cocultures was 10-15 times higher when LSECs were cultured as a bottom layer (with an intervening collagen layer) and as a mixture in a sandwich configuration, and native CYP 1A1/2 activity was at least 20 times higher than monoculture controls. Together, these data suggest that collagen gel-based hepatocyte-LSEC cocultures are highly suitable models for stabilization and long-term culture of both cell types. In summary, these results indicate that collagen gel-based hepatocyte-LSEC coculture models are promising for in vitro toxicity testing, and liver model development studies.

Integration of the Herbst and Begg appliance in the management of severe Class II malocclusion.

The efficacy of the Herbst appliance in a normalizing sagittal relationship in patients with a Class II malocclusion is well-documented. This case report describes the treatment of a 14-year-old male patient with severe Class II Division 1 malocclusion due to retrognathic mandible and mildly prognathic maxilla, convex profile, and lip trap. He had severely proclined maxillary incisors and retroclined mandibular incisors, overjet of 13 mm and overbite of 7 mm. Since the patient was in the peak pubertal growth phase, growth modulation was carried out with the Herbst appliance for 8 months, followed by fixed appliance therapy with the Begg appliance for 11 months. Combination of Herbst and Begg appliance led to a very favorable treatment outcome and greatly improved the patient's appearance.

Mandibular incisor extractions in orthodontics: pitfalls and triumphs: a report of three cases.

Mandibular incisor extraction therapy has been used as a treatment option since the early 1900s to relieve tooth size-arch length discrepancies in the anterior segment of the mandible. The advantages of this therapy include potential reduction in treatment time, possibility of achieving better long-term stability in the mandibular anterior segment since inter canine width is not increased and maintenance of the soft-tissue profile because retraction of the mandibular incisors is less compared with mandibular premolar extractions These advantages are counterbalanced, however, by some potential disadvantages. The most significant of these is the possibility of the space reopening in the long term, an occlusal result less than ideal because of a significant tooth-mass reduction in the anterior mandibular region, development of an open gingival embrasure and the need for permanent or long term retention. We present three cases with three different indications for mandibular incisor extraction where the patient was benefited despite this atypical extraction pattern.

A novel ultrathin collagen nanolayer assembly for 3-D microtissue engineering: Layer-by-layer collagen deposition for long-term stable microfluidic hepatocyte culture.

The creation of stable hepatocyte cultures using cell-matrix interactions has proven difficult in microdevices due to dimensional constraints limiting the utility of classic tissue culture techniques that involve the use of hydrogels such as the collagen "double gel" or "overlay". To translate the collagen overlay technique into microdevices, we modified collagen using succinylation and methylation reactions to create polyanionic and polycationic collagen solutions, and deposited them layer-by-layer to create ultrathin collagen nanolayers on hepatocytes. These ultrathin collagen layers covered hepatocytes in microdevices and 1) maintained cell morphology, viability, and polarity, 2) induced bile canalicular formation and actin reorganization, and 3) maintained albumin and urea secretions and CYP activity similar to those observed in hepatocytes in collagen double gel hepatocytes in plate cultures. Beyond the immediate applications of this technique to create stable, in vitro microfluidic hepatocyte cultures for drug toxicity testing, this technique is generally applicable as a thin biomaterial for other 3D microtissues.

Dynamic interplay of flow and collagen stabilizes primary hepatocytes culture in a microfluidic platform.

The creation of stable flow cultures of hepatocytes is highly desirable for the development of platforms for drug toxicity screening, bio-artificial liver support devices, and models for investigating liver physiology and pathophysiology. Given that hepatocytes cultured using the collagen overlay or in 'sandwich' configuration maintain a wide range of differentiated functions, we describe a simple method for adapting this culture configuration within a microfluidic device. The device design consists of a porous membrane sandwiched between two layers of PDMS resulting in a two-chambered device. In the bottom chamber, hepatocytes are cultured in the collagen sandwich configuration, while the top chamber is accessible for flow. We demonstrate that hepatocytes cultured under flow exhibit higher albumin and urea secretions and induce cytochrome P450 1A1 activity in comparison to static cultures. Furthermore, over two weeks, hepatocytes cultured under flow show a well-connected cellular network with bile canaliculi formation, whereas static cultures show formation of gaps in the cellular network that progressively increase over time. Although enhanced functional response of hepatocytes cultured under flow has been observed in multiple prior studies, the exact mechanism for this flow induced effect remains unknown. In our work, we identified that hepatocytes secrete a higher level of collagen in the flow cultures; inhibiting collagen secretion within the flow cultures reduced albumin secretion and restored the appearance of gaps in the cellular network similar to the static cultures. These results demonstrate the importance of the increased collagen secretion by hepatocytes cultured under flow as a mechanism to maintain a well-connected cellular network and a differentiated function.

In vitro platforms for evaluating liver toxicity.

The liver is a heterogeneous organ with many vital functions, including metabolism of pharmaceutical drugs and is highly susceptible to injury from these substances. The etiology of drug-induced liver disease is still debated although generally regarded as a continuum between an activated immune response and hepatocyte metabolic dysfunction, most often resulting from an intermediate reactive metabolite. This debate stems from the fact that current animal and in vitro models provide limited physiologically relevant information, and their shortcomings have resulted in "silent" hepatotoxic drugs being introduced into clinical trials, garnering huge financial losses for drug companies through withdrawals and late stage clinical failures. As we advance our understanding into the molecular processes leading to liver injury, it is increasingly clear that (a) the pathologic lesion is not only due to liver parenchyma but is also due to the interactions between the hepatocytes and the resident liver immune cells, stellate cells, and endothelial cells; and (b) animal models do not reflect the human cell interactions. Therefore, a predictive human, in vitro model must address the interactions between the major human liver cell types and measure key determinants of injury such as the dosage and metabolism of the drug, the stress response, cholestatic effect, and the immune and fibrotic response. In this mini-review, we first discuss the current state of macro-scale in vitro liver culture systems with examples that have been commercialized. We then introduce the paradigm of microfluidic culture systems that aim to mimic the liver with physiologically relevant dimensions, cellular structure, perfusion, and mass transport by taking advantage of micro and nanofabrication technologies. We review the most prominent liver-on-a-chip platforms in terms of their physiological relevance and drug response. We conclude with a commentary on other critical advances such as the deployment of fluorescence-based biosensors to identify relevant toxicity pathways, as well as computational models to create a predictive tool.

Establishment of soft tissue norms for the north Indian population based on laymen perception.

In this study we aimed to determine the soft tissue norms for the North Indian population based on the laymen perception of facial esthetics and to test the hypothesis that there are racial differences in cephalometric measurement between North Indians and White Americans norms. Two sets (Facial frontal and profile photographs) of 170 standardized facial photographs (76 males and 94 females in the age group of 18-28 years) were taken. A panel of judges which consisted of 20 laymen evaluated the photographs on the visual analogue scale to select a sample of 120 subjects (60 males and 60 females), which included individuals with esthetically pleasing appearance. Digital lateral cephalograms were made and anatomic landmarks were identified directly on the digital images. Seventeen soft tissue variables taken from Subtenley's, Holdaway's, Ricketts and Legan's analysis were calculated electronically using the Dolphin (version 9) software package. Most measurements were similar to the white American norms, some differences were noticed in nasal prominence, basic upper lip thickness, and 'H' angle measurements. The independent-sample t test was used to compare the measurement differences of the North Indian men and women. North Indian males have relatively prominent and thicker upper lip, and increased basic upper lip thickness than the females. Lower lip was found to be more protrusive in females than in males.

Towards a three-dimensional microfluidic liver platform for predicting drug efficacy and toxicity in humans.

Although the process of drug development requires efficacy and toxicity testing in animals prior to human testing, animal models have limited ability to accurately predict human responses to xenobiotics and other insults. Societal pressures are also focusing on reduction of and, ultimately, replacement of animal testing. However, a variety of in vitro models, explored over the last decade, have not been powerful enough to replace animal models. New initiatives sponsored by several US federal agencies seek to address this problem by funding the development of physiologically relevant human organ models on microscopic chips. The eventual goal is to simulate a human-on-a-chip, by interconnecting the organ models, thereby replacing animal testing in drug discovery and development. As part of this initiative, we aim to build a three-dimensional human liver chip that mimics the acinus, the smallest functional unit of the liver, including its oxygen gradient. Our liver-on-a-chip platform will deliver a microfluidic three-dimensional co-culture environment with stable synthetic and enzymatic function for at least 4 weeks. Sentinel cells that contain fluorescent biosensors will be integrated into the chip to provide multiplexed, real-time readouts of key liver functions and pathology. We are also developing a database to manage experimental data and harness external information to interpret the multimodal data and create a predictive platform.

Gingival enlargement and mesiodens associated with generalized aggressive periodontitis: a case report.

UNLABELLED: This case report describes the management of an 18-year-old female who presented with generalized aggressive periodontitis, gingival enlargement and a mesiodens. Diagnosis for aggressive periodontitis was determined based on history, clinical findings and radiographic examination. Treatment included oral prophylaxis, extraction of the mesiodens and elimination of infectious microorganisms, using a combination of surgical intervention and antimicrobial therapy with long-term maintenance. CLINICAL RELEVANCE: Presence of gingival enlargement in cases of aggressive periodontitis may be clinically confusing; hence, the diagnosis should always be based on the patient's history as well as the clinical and radiographic findings.

Multiple supernumerary teeth associated with an impacted maxillary central incisor: Surgical and orthodontic management.

Various anomalies in the size, shape, number, structure and eruption of the teeth are often observed clinical conditions. Supernumerary teeth can be found in almost any region of the dental arch, and most of the times they are asymptomatic, and are routinely found during radiographic evaluation. The most common cause of impacted maxillary incisors is the presence of the supernumerary teeth. This paper describes a case of multiple supernumerary teeth associated with an impacted permanent maxillary central incisor in an 11-year old child along with its surgical and orthodontic management.

Interkingdom adenosine signal reduces Pseudomonas aeruginosa pathogenicity.

Pseudomonas aeruginosa is becoming recognized as an important pathogen in the gastrointestinal (GI) tract. Here we demonstrate that adenosine, derived from hydrolysis of ATP from the eucaryotic host, is a potent interkingdom signal in the GI tract for this pathogen. The addition of adenosine nearly abolished P. aeruginosa biofilm formation and abolished swarming by preventing production of rhamnolipids. Since the adenosine metabolite inosine did not affect biofilm formation and since a mutant unable to metabolize adenosine behaved like the wild-type strain, adenosine metabolism is not required to reduce pathogenicity. Adenosine also reduces production of the virulence factors pyocyanin, elastase, extracellular polysaccharide, siderophores and the Pseudomonas quinolone signal which led to reduced virulence with Caenorhabditis elegans. To provide insights into how adenosine reduces the virulence of P. aeruginosa, a whole-transcriptome analysis was conducted which revealed that adenosine addition represses genes similar to an iron-replete condition; however, adenosine did not directly bind Fur. Therefore, adenosine decreases P. aeruginosa pathogenicity as an interkingdom signal by causing genes related to iron acquisition to be repressed.

A microfluidic device for high throughput bacterial biofilm studies.

Bacteria are almost always found in ecological niches as matrix-encased, surface-associated, multi-species communities known as biofilms. It is well established that soluble chemical signals produced by the bacteria influence the organization and structure of the biofilm; therefore, there is significant interest in understanding how different chemical signals are coordinately utilized for community development. Conventional methods for investigating biofilm formation such as macro-scale flow cells are low-throughput, require large volumes, and do not allow spatial and temporal control of biofilm community formation. Here, we describe the development of a PDMS-based two-layer microfluidic flow cell (µFC) device for investigating bacterial biofilm formation and organization in response to different concentrations of soluble signals. The µFC device contains eight separate microchambers for cultivating biofilms exposed to eight different concentrations of signals through a single diffusive mixing-based concentration gradient generator. The presence of pneumatic valves and a separate cell seeding port that is independent from gradient-mixing channels offers complete isolation of the biofilm microchamber from the gradient mixer, and also performs well under continuous, batch or semi-batch conditions. We demonstrate the utility of the µFC by studying the effect of different concentrations of indole-like biofilm signals (7-hydroxyindole and isatin), either individually or in combination, on biofilm development of pathogenic E. coli. This model can be used for developing a fundamental understanding of events leading to bacterial attachment to surfaces that are important in infections and chemicals that influence the biofilm formation or inhibition.

Synthetic quorum-sensing circuit to control consortial biofilm formation and dispersal in a microfluidic device.

To utilize biofilms for chemical transformations in biorefineries they need to be controlled and replaced. Previously, we engineered the global regulator Hha and cyclic diguanylate-binding BdcA to create proteins that enable biofilm dispersal. Here we report a biofilm circuit that utilizes these two dispersal proteins along with a population-driven quorum-sensing switch. With this synthetic circuit, in a novel microfluidic device, we form an initial colonizer biofilm, introduce a second cell type (dispersers) into this existing biofilm, form a robust dual-species biofilm and displace the initial colonizer cells in the biofilm with an extracellular signal from the disperser cells. We also remove the disperser biofilm with a chemically induced switch, and the consortial population could tune. Therefore, for the first time, cells have been engineered that are able to displace an existing biofilm and then be removed on command allowing one to control consortial biofilm formation for various applications.

Chemotaxis to the quorum-sensing signal AI-2 requires the Tsr chemoreceptor and the periplasmic LsrB AI-2-binding protein.

AI-2 is an autoinducer made by many bacteria. LsrB binds AI-2 in the periplasm, and Tsr is the l-serine chemoreceptor. We show that AI-2 strongly attracts Escherichia coli. Both LsrB and Tsr are necessary for sensing AI-2, but AI-2 uptake is not, suggesting that LsrB and Tsr interact directly in the periplasm.

Microfluidic co-culture of epithelial cells and bacteria for investigating soluble signal-mediated interactions.

The human gastrointestinal (GI) tract is a unique environment in which intestinal epithelial cells and non-pathogenic (commensal) bacteria coexist. It has been proposed that the microenvironment that the pathogen encounters in the commensal layer is important in determining the extent of colonization. Current culture methods for investigating pathogen colonization are not well suited for investigating this hypothesis as they do not enable co-culture of bacteria and epithelial cells in a manner that mimics the GI tract microenvironment. Here we describe a microfluidic co-culture model that enables independent culture of eukaryotic cells and bacteria, and testing the effect of the commensal microenvironment on pathogen colonization. The co-culture model is demonstrated by developing a commensal Escherichia coli biofilm among HeLa cells, followed by introduction of enterohemorrhagic E. coli (EHEC) into the commensal island, in a sequence that mimics the sequence of events in GI tract infection.