A Hybrid Approach for Energy Consumption and Improvement in Sensor Network Lifespan in Wireless Sensor Networks.

In this paper, we propose an improved clustering algorithm for wireless sensor networks (WSNs) that aims to increase network lifetime and efficiency. We introduce an enhanced fuzzy spider monkey optimization technique and a hidden Markov model-based clustering algorithm for selecting cluster heads. Our approach considers factors such as network cluster head energy, cluster head density, and cluster head position. We also enhance the energy-efficient routing strategy for connecting cluster heads to the base station. Additionally, we introduce a polling control method to improve network performance while maintaining energy efficiency during steady transmission periods. Simulation results demonstrate a 1.2% improvement in network performance using our proposed model.

Immunoinformatic based designing of potential immunogenic novel mRNA and peptide-based prophylactic vaccines against H5N1 and H7N9 avian influenza viruses.

Influenza viruses are the most common cause of serious respiratory illnesses worldwide and are responsible for a significant number of annual fatalities. Therefore, it is crucial to look for new immunogenic sites that might trigger an effective immune response. In the present study, bioinformatics tools were used to design mRNA and multiepitope-based vaccines against H5N1 and H7N9 subtypes of avian influenza viruses. Several Immunoinformatic tools were employed to extrapolate T and B lymphocyte epitopes of HA and NA proteins of both subtypes. The molecular docking approach was used to dock the selected HTL and CTL epitopes with the corresponding MHC molecules. Eight (8) CTL, four (4) HTL, and Six (6) linear B cell epitopes were chosen for the structural arrangement of mRNA and of peptide-based prophylactic vaccine designs. Different physicochemical characteristics of the selected epitopes fitted with suitable linkers were analyzed. High antigenic, non-toxic, and non-allergenic features of the designed vaccines were noted at a neutral physiological pH. Codon optimization tool was used to check the GC content and CAI value of constructed MEVC-Flu vaccine, which were recorded to be 50.42% and 0.97 respectively. the GC content and CAI value verify the stable expression of vaccine in pET28a + vector. In-silico immunological simulation the MEVC-Flu vaccine construct revealed a high level of immune responses. The molecular dynamics simulation and docking results confirmed the stable interaction of TLR-8 and MEVC-Flu vaccine. Based on these parameters, vaccine constructs can be regarded as an optimistic choice against H5N1 and H7N9 strains of the influenza virus. Further experimental testing of these prophylactic vaccine designs against pathogenic avian influenza strains may clarify their safety and efficacy.Communicated by Ramaswamy H. Sarma.

Preparation and Performance Analysis of 3D Thermoformed Fluidic Polymer Temperature Sensors for Aquatic and Terrestrial Applications.

Employing a combination of Polyethylene terephthalate (PET) thermoforming and 3D-printed cylindrical patterns, we carefully engineer a linear resistive temperature sensor. This intricate process involves initial PET thermoforming, yielding a hollow cylindrical chamber. This chamber is then precisely infused with a composite fluid of graphite and water glue. Ensuring electrical connectivity, both ends are affixed with metal wires and securely sealed using a hot gun. This cost-effective, versatile sensor adeptly gauges temperature shifts by assessing composite fluid resistance alterations. Its PET outer surface grants immunity to water and solubility concerns, enabling application in aquatic and aerial settings without extra encapsulation. Rigorous testing reveals the sensor's linearity and stability within a 10 °C to 60 °C range, whether submerged or airborne. Beyond 65 °C, plastic deformation arises. To mitigate hysteresis, a 58 °C operational limit is recommended. Examining fluidic composite width and length effects, we ascertain a 12 Ω/°C sensitivity for these linear sensors, a hallmark of their precision. Impressive response and recovery times of 4 and 8 s, respectively, highlight their efficiency. These findings endorse thermoforming's potential for fabricating advanced temperature sensors. This cost-effective approach's adaptability underscores its viability for diverse applications.

Tuning the optoelectronic properties of hematite with rhodium doping for photoelectrochemical water splitting using density functional theory approach.

Hematite (Fe2O3) is one of the best candidates for photoelectrochemical water splitting due to its abundance and suitable bandgap. However, its efficiency is mostly impeded due to the intrinsically low conductivity and poor light absorption. In this study, we targeted this intrinsic behavior to investigate the thermodynamic stability, photoconductivity and optical properties of rhodium doped hematite using density functional theory. The calculated formation energy of pristine and rhodium doped hematite was - 4.47 eV and - 5.34 eV respectively, suggesting that the doped material is thermodynamically more stable. The DFT results established that the bandgap of doped hematite narrowed down to the lower edge (1.61 eV) in the visible region which enhanced the optical absorption and photoconductivity of the material. Moreover, doped hematite has the ability to absorb a broad spectrum (250-800) nm. The enhanced optical absorption boosted the photocurrent and incident photon to current efficiency. The calculated results also showed that the incorporation of rhodium in hematite induced a redshift in optical properties.

Antiproliferative activity of the dibenzylideneacetone derivate (E)-3-ethyl-4-(4-nitrophenyl)but­3-en-2-one in Trypanosoma cruzi.

Chagas disease is one of the most prevalent neglected diseases in the world. The illness is caused by Trypanosoma cruzi, a protozoan parasite with a complex life cycle and three morphologically distinct developmental stages. Nowadays, the only treatment is based on two nitro-derivative drugs, benznidazole and nifurtimox, which cause serious side effects. Since the treatment is limited, the search for new treatment options for patients with Chagas disease is highly necessary. In this study we analyzed the substance A11K3, a dibenzylideneacetone (DBA). DBAs have an acyclic dienone attached to aryl groups in both ß-positions and studies have shown that they have biological activity against tumors cells, bacteria, and protozoa such as T. cruzi and Leishmania spp. Here we show that A11K3 is active against all three T. cruzi evolutionary forms: the epimastigote (IC50 = 3.3 ± 0.8), the trypomastigote (EC50 = 24 ± 4.3) and the intracellular amastigote (IC50 = 9.3 ± 0.5 µM). A cytotoxicity assay in LLCMK2 cells showed a CC50 of 239.2 ± 15.7 µM giving a selectivity index (CC50/IC50) of 72.7 for epimastigotes, 9.9 for trypomastigotes and 25.9 for intracellular amastigotes. Morphological and ultrastructural analysis of the parasites treated with A11K3 by TEM and SEM revealed alterations in the Golgi complex, mitochondria, plasma membrane and cell body, with an increase of autophagic vacuoles and lipid bodies. Biochemical assays of A11K3-treated T. cruzi showed an increase of ROS, plasma membrane ruptures, lipid peroxidation, mitochondrial membrane depolarization with a decrease in ATP and accumulation of autophagic vacuoles. The results lead to the hypothesis that A11K3 causes death of the protozoan through events such as plasma membrane and mitochondrial alterations and autophagy, characteristic of cell collapse.

Dose-dependent production of linoleic acid analogues in food derived Lactobacillus plantarum K25 and in silico characterization of relevant reactions.

The objective of this study was to assess and scrutinize the competency of probiotic L. plantarum K25 to produce linoleic acid analogues in the medium supplemented with different concentrations of linoleic acid, ranging from 1% to 10%, in a dose dependent manner. The analogues produced were identified and quantitated by GC-MS and in silico studies were done to confirm enzymatic reactions involved in its conversion. The results showed that L. plantarum K25 could convert linoleic acid at different concentrations to 9 different fatty acid analogues at concentrations ranging from 0.01 to 17.24 mg/L. Among these metabolites, formation of an essential fatty acid, the linolenic acid, in media supplemented with 9% linoleic acid, is being reported for the first time. Putative candidate enzymes involved in biotransformation of linoleic acid into linoleic acid analogues were identified in the whole genome of L. plantarum K25, which was sequenced previously. In silico studies confirmed that many enzymes, including linoleate isomerase and dehydrogenase, may be involved in biotransformation of linoleic acid into linoleic acid analogues. Both enzymes could effectively bind the linoleic acid molecule, mainly by forming hydrogen bonding between the acidic groups of linoleic acid and the proline residues at the active sites of the enzymes, validating putative reaction partners.

In silico characterization of linoleic acid biotransformation to rumenic acid in food derived Lactobacillus plantarum YW11.

Lactobacillus plantarum YW11 capability to convert linoleic acid into conjugated linoleic acid and other metabolites was studied in a dose-dependent manner by supplementing LA at different concentrations. L. plantarum YW11 displayed a uniform distinctive growth curve of CLA and other metabolites at concentrations of LA ranging from 1% (w/v) to 10% (w/v), with slightly increased growth at higher LA concentrations. The biotransformation capability of L. plantarum YW11 evaluated by GC-MS revealed a total of one CLA isomer, i.e. 9-cis,11-trans-octadecadienoic acid, also known as the rumenic acid (RA), one linoleic acid isomer (linoelaidic acid), and LA metabolites: (E)-9-octadecenoic acid ethyl ester, trans, trans-9,12-octadecadienoic acid, propyl ester and stearic acid. All the metabolites of linoleic acid were produced from 1 to 10% LA supplemented MRS media, while surprisingly the only conjugated linoleic acid compound was produced at 10% LA. To assess the presence of putative enzymes, responsible for conversion of LA into CLA, in silico characterization was carried out. The in silico characterization revealed presence of four enzymes (10-linoleic acid hydratase, linoleate isomerase, acetoacetate decarboxylase and dehydrogenase) that may be involved in the production of CLA (rumenic acid) and LA isomers. The biotransformation ability of L. plantarum YW11 to convert LA into RA has great prospects for biotechnological and industrial implications that could be exploited in the future scale-up experiments.

Synthesis, characterization, molecular docking, analgesic, antiplatelet and anticoagulant effects of dibenzylidene ketone derivatives.

In this study dibenzylidene ketone derivatives (2E,5E)-2-(4-methoxybenzylidene)-5-(4-nitrobenzylidene) cyclopentanone (AK-1a) and (1E,4E)-4-(4-nitrobenzylidene)-1-(4-nitrophenyl) oct-1-en-3-one (AK-2a) were newly synthesized, inspired from curcuminoids natural origin. Novel scheme was used for synthesis of AK-1a and AK-2a. The synthesized compounds were characterized by spectroscopic techniques. AK-1a and AK-2a showed high computational affinities (E-value > - 9.0 kcal/mol) against cyclooxygenase-1, cyclooxygenase-2, proteinase-activated receptor 1 and vitamin K epoxide reductase. AK-1a and AK-2a showed moderate docking affinities (E-value > - 8.0 kcal/mol) against mu receptor, kappa receptor, delta receptor, human capsaicin receptor, glycoprotein IIb/IIIa, prostacyclin receptor I2, antithrombin-III, factor-II and factor-X. AK-1a and AK-2a showed lower affinities (E-value > - 7.0 kcal/mol) against purinoceptor-3, glycoprotein-VI and purinergic receptor P2Y12. In analgesic activity, AK-1a and AK-2a decreased numbers of acetic acid-induced writhes (P < 0.001 vs. saline group) in mice. AK-1a and AK-2a significantly prolonged the latency time of mice (P < 0.05, P < 0.01 and P < 0.001 vs. saline group) in hotplate assay. AK-1a and AK-2a inhibited arachidonic acid and adenosine diphosphate induced platelet aggregation with IC50 values of 65.2, 37.7, 750.4 and 422 µM respectively. At 30, 100, 300 and 1000 µM concentrations, AK-1a and AK-2a increased plasma recalcification time (P < 0.001 and P < 0.001 vs. saline group) respectively. At 100, 300 and 1000 µg/kg doses, AK-1a and AK-2a effectively prolonged bleeding time (P < 0.001 and P < 0.01 vs. saline group) respectively. Thus in-silico, in-vitro and in-vivo investigation of AK-1a and AK-2a reports their analgesic, antiplatelet and anticoagulant actions.

Fortification of durum wheat semolina with detoxified matri (Lathyrus sativus) flour to improve the nutritional properties of pasta.

Durum wheat semolina (DWS) can be enriched with legume flours to produce more nutritious but high-quality pasta. DWS was substituted with detoxified matri (Lathyrus sativus) flour (DMF) at 5-25%, which in spaghetti increased the levels of protein, lipid, fibre and ash but decreased nitrogen-free extract. Water absorption, arrival time and dough development time increased from 63.1 to 69.2%, 1.7 to 2.4 and 2.3 to 3.3 min, respectively, while dough stability, consistency and tolerance index decreased. DMF addition increased cooking loss (4.8-5.8%) and hardness (13.2-16.5 N) but decreased percent rehydration. Based on farinographic (departure time), cooking quality (adhesiveness) and cooking loss thresholds for DMF at 15%, the effects of xanthan gum (XG) addition on the cooking qualities of the corresponding spaghetti were determined. XG up to 3% limited cooking loss (4.97 vs 5.4%) and improved hardness, compared to samples lacking XG. Considering functional, cooking and nutritional properties of spaghetti, incorporation of 15% DMF and 3% XG appeared optimal.

Differential metabolism of diastereoisomeric diterpenes by Preussia minima, found as endophytic fungus in Cupressus lusitanica.

The plant diastereoisomeric diterpenes ent-pimara-8(14)-15-dien-19-oic acid, obtained from Viguiera arenaria, and isopimara-8(14)-15-dien-18-oic acid, isolated from Cupressus lusitanica, were distinctly functionalized by the enzymes produced in whole cell cultures of the fungus Preussia minima, isolated from surface sterilized stems of C. lusitanica. The ent-pimaradienoic acid was transformed into the known 7ß-hydroxy-ent-pimara-8(14)-15-dien-19-oic acid, and into the novel diterpenes 7-oxo-8 ß-hydroxy-ent-pimara-8(14)-15-dien-19-oic and 7-oxo-9ß-hydroxy-ent-pimara-8(14)-15-dien-19-oic acids. Isopimara-8(14)-15-dien-18-oic acid was converted into novel diterpenes 11α-hydroxyisopimara-8(14)-15-dien-18-oic acid, 7ß,11α-dihydroxyisopimara-8(14)-15-dien-18-oic acid, and 1ß,11α-dihydroxyisopimara-8(14)-15-dien-18-oic acid, along with the known 7ß-hydroxyisopimara-8(14)-15-dien-18-oic acid. All compounds were isolated and fully characterized by 1D and 2D NMR, especially 13C NMR. The diterpene bioproduct 7-oxo-9ß-hydroxy-ent-pimara-8(14)-15-dien-19-oic acid is an isomer of sphaeropsidin C, a phytotoxin that affects cypress trees produced by Shaeropsis sapinea, one of the main phytopathogen of Cupressus. The differential metabolism of the diterpene isomers used as substrates for biotransformation was interpreted with the help of computational molecular docking calculations, considering as target enzymes those of cytochrome P450 group.

Effects of (1E,4E)-2-Methyl-1,5-bis(4-nitrophenyl)penta-1,4-dien-3-one on Trypanosoma cruzi and Its Combinational Effect with Benznidazole, Ketoconazole, or Fluconazole.

This study reports the activity induced by (1E,4E)-2-methyl-1,5-bis(4-nitrophenyl)penta-1,4-dien-3-one (A3K2A3) against Trypanosoma cruzi. This compound showed trypanocidal activity against the multiplicative epimastigote and amastigote forms of this protozoan, with IC50 values of 1.99 ± 0.17 and 1.20 ± 0.16 µM, respectively, and EC50 value of 15.57 ± 0.34 µM against trypomastigotes. The combination of A3K2A3 with benznidazole or ketoconazole demonstrated strong synergism, increasing effectiveness against trypomastigotes or epimastigotes of T. cruzi. In addition, the drug combination of A3K2A3 with benznidazole or ketoconazole on LLCMK2 cells demonstrated an antagonist effect, which resulted in greater protection of the cells from drug damage. The combination of the compound with fluconazole was not effective. Transmission and scanning electron micrographs showed changes on parasites, mainly in the cytoplasmatic membrane, nucleus, mitochondrion, and Golgi complex, and a large increase in the number of autophagosome-like structures and lipid-storage bodies, accompanied by volume reduction and rounding of the parasite. A3K2A3 might be a promising compound against T. cruzi.

Allelopathy of Bracken Fern (Pteridium arachnoideum): New Evidence from Green Fronds, Litter, and Soil.

The neotropical bracken fern Pteridium arachnoideum (Kaulf.) Maxon. (Dennstaedtiaceae) is described as an aggressive pioneer plant species. It invades abandoned or newly burned areas and represents a management challenge at these invaded sites. Native to the Atlantic Forest and Cerrado (Tropical Savanna) Brazilian biomes, P. arachnoideum has nevertheless become very problematic in these conservation hotspots. Despite some reports suggesting a possible role of allelopathy in this plant's dominance, until now there has been little evidence of isolated and individually identified compounds with phytotoxic activities present in its tissues or in the surrounding environment. Thus, the aim of this study was to investigate the allelopathic potential of P. arachnoideum by isolating and identifying any secondary metabolites with phytotoxic activity in its tissues, litter, and soil. Bioguided phytochemical investigation led to the isolation and identification of the proanthocyanidin selligueain A as the major secondary compound in the green fronds and litter of this fern. It is produced by P. arachnoideum in its green fronds, remains unaltered during the senescence process, and is the major secondary compound present in litter. Selligueain A showed phytotoxic activity against the selected target species sesame (Sesamum indicum) early development. In particular, the compound inhibited root and stem growth, and root metaxylem cell size but did not affect chlorophyll content. This compound can be considered as an allelochemical because it is present in the soil under P. arachnoideum patches as one of the major compounds in the soil solution. This is the first report of the presence of selligueain A in any member of the Dennstaedtiaceae family and the first time an isolated and identified allelochemical produced by members of the Pteridium species complex has been described. This evidence of selligueain A as a putative allelochemical of P. arachnoideum reinforces the role of allelopathy in the dominance processes of this plant in the areas where it occurs.

Cloning, Purification and Characterization of a Highly Thermostable Amylase Gene of Thermotoga petrophila into Escherichia coli.

A putative α-amylase gene of Thermotoga petrophila was cloned and expressed in Escherichia coli BL21 (DE3) using pET-21a (+), as an expression vector. The growth conditions were optimized for maximal expression of the α-amylase using various parameters, such as pH, temperature, time of induction and addition of an inducer. The optimum temperature and pH for the maximum expression of α-amylase were 22 °C and 7.0 pH units, respectively. Purification of the recombinant enzyme was carried out by heat treatment method, followed by ion exchange chromatography with 34.6-fold purification having specific activity of 126.31 U mg(-1) and a recovery of 56.25%. Molecular weight of the purified α-amylase, 70 kDa, was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable at 100 °C temperature and at pH of 7.0. The enzyme activity was increased in the presence of metal ions especially Ca(+2) and decreased in the presence of EDTA indicating that the α-amylase was a metalloenzyme. However, addition of 1% Tween 20, Tween 80 and ß-mercaptoethanol constrained the enzyme activity to 87, 96 and 89%, respectively. No considerable effect of organic solvents (ethanol, methanol, isopropanol, acetone and n-butanol) was observed on enzyme activity. With soluble starch as a substrate, the enzyme activity under optimized conditions was 73.8 U mg(-1). The α-amylase enzyme was active to hydrolyse starch forming maltose.

Dibenzylideneacetones Are Potent Trypanocidal Compounds That Affect the Trypanosoma cruzi Redox System.

Despite ongoing efforts, the available treatments for Chagas' disease are still unsatisfactory, especially in the chronic phase of the disease. Our previous study reported the strong trypanocidal activity of the dibenzylideneacetones A3K2A1 and A3K2A3 against Trypanosoma cruzi (Z. Ud Din, T. P. Fill, F. F. de Assis, D. Lazarin-Bidóia, V. Kaplum, F. P. Garcia, C. V. Nakamura, K. T. de Oliveira, and E. Rodrigues-Filho, Bioorg Med Chem 22:1121-1127, 2014, http://dx.doi.org/10.1016/j.bmc.2013.12.020). In the present study, we investigated the mechanisms of action of these compounds that are involved in parasite death. We showed that A3K2A1 and A3K2A3 induced oxidative stress in the three parasitic forms, especially trypomastigotes, reflected by an increase in oxidant species production and depletion of the endogenous antioxidant system. This oxidative imbalance culminated in damage in essential cell structures of T. cruzi, reflected by lipid peroxidation and DNA fragmentation. Consequently, A3K2A1 and A3K2A3 induced vital alterations in T. cruzi, leading to parasite death through the three pathways, apoptosis, autophagy, and necrosis.

Purification and characterization of cloned alkaline protease gene of Geobacillus stearothermophilus.

Thermostable alkaline serine protease gene of Geobacillus stearothermophilus B-1172 was cloned and expressed in Escherichia coli BL21 (DE3) using pET-22b(+), as an expression vector. The growth conditions were optimized for maximal production of the protease using variable fermentation parameters, i.e., pH, temperature, and addition of an inducer. Protease, thus produced, was purified by ammonium sulfate precipitation followed by ion exchange chromatography with 13.7-fold purification, with specific activity of 97.5 U mg(-1) , and a recovery of 23.6%. Molecular weight of the purified protease, 39 kDa, was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable at 90 °C at pH 9. The enzyme activity was steady in the presence of EDTA indicating that the protease was not a metalloprotease. No significant change in the activity of protease after addition of various metal ions further strengthened this fact. However, an addition of 1% Triton X-100 or SDS surfactants constrained the enzyme specific activity to 34 and 19%, respectively. Among organic solvents, an addition of 1-butanol (20%) augmented the enzyme activity by 29% of the original activity. With casein as a substrate, the enzyme activity under optimized conditions was found to be 73.8 U mg(-1) . The effect of protease expression on the host cells growth was also studied and found to negatively affect E. coli cells to certain extent. Catalytic domains of serine proteases from eight important thermostable organisms were analyzed through WebLogo and found to be conserved in all serine protease sequences suggesting that protease of G. stearothermophilus could be beneficially used as a biocontrol agent and in many industries including detergent industry.

Unsymmetrical 1,5-diaryl-3-oxo-1,4-pentadienyls and their evaluation as antiparasitic agents.

In this work the synthesis and antiparasitical activity of new 1,5-diaryl-3-oxo-1,4-pentadienyl derivatives are described. First, compounds 1a, 1b, 1c and 1d were prepared by acid-catalyzed aldol reaction between 2-butanone and benzaldehyde, anisaldehyde, p-N,N-dimethylaminobenzaldehyde and p-nitrobenzaldehyde. Reacting each of the methyl ketones 1a, 1b, 1c and 1d with the p-substituted benzaldehydes under basic-catalyzed aldol reaction, we further prepared compounds 2a-2p. All twenty compounds were evaluated for antiproliferative activity, particularly for promastigote of Leishmania amazonensis and epimastigote of Trypanosoma cruzi. All compounds showed good activity while nitro compounds 2i and 2k showed inhibition activity at a few µM.

Growth outcomes of weight faltering in infancy in ALSPAC.

OBJECTIVE: The goal of this study was to investigate growth outcomes in term infants with weight faltering. METHODS: Conditional weight gain was calculated on term infants from the Avon Longitudinal Study of Parents and Children. Cases of weight faltering were infants with a conditional weight gain below the fifth centile. Outcome growth measurements included weight and length/height (from 9 months to 13 years), BMI, mid-arm circumference, and waist circumference (at 7, 10, and 13 years). RESULTS: Weight data were available on 11 499 infants; 507 had "early" weight faltering (before 8 weeks), and 480 had "late" weight faltering (between 8 weeks and 9 months). The early group showed enhanced weight gain from 8 weeks until 2 years, then gained weight at the same rate as the controls. Gain in height was proportionally slower than gain in weight through childhood. By 13 years, they had BMI, mid-arm circumference, and waist circumference similar to the controls. The late group showed steady weight gain throughout childhood; enhanced weight gain compared with the controls only occurred between 7 and 10 years. Gain in height was proportional to gain in weight. This group remained considerably lighter and shorter than the controls up to the age of 13 years. CONCLUSIONS: Children with weight faltering before 8 weeks showed a different pattern of "catch-up" to those with weight faltering later in infancy. By 13 years, the anthropometric profile of the 2 groups was within population norms.

Small intestinal model for electrically propelled capsule endoscopy.

The aim of this research is to propose a small intestine model for electrically propelled capsule endoscopy. The electrical stimulus can cause contraction of the small intestine and propel the capsule along the lumen. The proposed model considered the drag and friction from the small intestine using a thin walled model and Stokes' drag equation. Further, contraction force from the small intestine was modeled by using regression analysis. From the proposed model, the acceleration and velocity of various exterior shapes of capsule were calculated, and two exterior shapes of capsules were proposed based on the internal volume of the capsules. The proposed capsules were fabricated and animal experiments were conducted. One of the proposed capsules showed an average (SD) velocity in forward direction of 2.91 ± 0.99 mm/s and 2.23 ± 0.78 mm/s in the backward direction, which was 5.2 times faster than that obtained in previous research. The proposed model can predict locomotion of the capsule based on various exterior shapes of the capsule.

Duodenum identification mechanism for capsule endoscopy.

The aim of this study is to implement a duodenum identification mechanism for capsule endoscopes because commercially available capsule endoscopes sometimes present a false negative diagnosis of the duodenum. One reason for the false negative diagnosis is that the duodenum is the fastest moving part within the gastrointestinal tract and the current frame rate of the capsule is not fast enough. When the capsule can automatically identify that it is in the duodenum, the frame rate of the capsule can be temporarily increased to reduce the possibility of a false negative diagnosis. This study proposes a mechanism to identify the duodenum using capacitive proximity sensors that can distinguish the surrounding tissue and transmit data using RF communication. The implemented capsule (D11 mm × L22 mm) was smaller than the commercially available capsule endoscopes, and power consumption was as low as 0.642 mW. Preexperiments were conducted to select an appropriate electrode width in order to increase the signal-to-noise ratio (SNR), and in vitro experiments were conducted to verify whether the implemented capsule could identify the duodenum within 3 s. The experiment showed that the identification rate of duodenum was 93% when the velocity of the capsule was less than 1 cm/s.

Optoelectronic stimulation of the brain using carbon nanotubes.

This paper presents the simulation results of a novel technique to stimulate the brain using a carbon nanotubes (CNT) based optically activated stimulator. This technique could be a promising alternative solution to overcome the limitations occurring in the conventional electrical stimulation of the brain and the newly developed opto-genetic stimulation. In this technique, the CNT stimulator, which generated an electrical current when exposed to light, was implanted in the brain. This current stimulated the nearby neurons to generate an action potential. The simulation results illustrated that a single-wall carbon nanotube of 50 nm² size could stimulate a 40 µm² area of the brain, whereas a multiwall carbon nanotube could cover a 12 µm² area of the brain. Additionally, simulations were also performed to determine the optimal shape and appropriate coating material for commercial optical stimulators to maximize the stimulation efficacy in the brain.