Low Transmission Rate Research Articles

Fingerprinting of Mycobacterium tuberculosis isolates by MIRU-VNTR genotyping and detection of isoniazid resistance by real-time PCR.

Introduction. Tuberculosis (TB) is a great public health problem in developing countries such as Egypt. Genotyping of Mycobacterium tuberculosis isolates has a prominent role in the field of TB prevention.Aim. This study aimed to evaluate real-time PCR using Minor Groove Binder (MGB) probes and to identify circulating lineages/sub-lineages of M. tuberculosis and their transmission patterns.Hypothesis. We hypothesize that MIRU-VNTR technique is efficient in identifying circulating M. tuberculosis lineages in Egypt.Methodology. Fifty sputum specimens positive for acid-fast bacilli were included. Isoniazid (INH) resistance was detected using the 1 % proportion method. Real-time PCR using MGB-probes was used for simultaneous detection of TB infection and INH resistance. Partial sequencing of the katG gene was used to confirm INH resistance results. A standard 15 Mycobacterial Interspersed Repetitive Unit Variable Number Tandem Repeat (15-MIRU-VNTR) approach was used for genotyping through the MIRU-VNTRplus online platform.Results. Only seven specimens showed phenotypic resistance to INH. M. tuberculosis was detected in all samples, while a mutation in the katG gene codon 315 was detected only in five samples, which were also phenotypically INH-resistant. Sequencing of the katG gene showed codon 315 mutation genotypically and phenotypically in the five INH-resistant isolates. Molecular genotyping of M. tuberculosis isolates revealed that the majority of isolates (26/50, 52 %) belonged to the S family of lineage_4. A low clustering rate (2 %) was observed among our isolates. According to the Hunter-Gaston Discriminatory Index (HGDI), 11 MIRU-VNTR loci were highly or moderately discriminative, while four loci were less polymorphic.Conclusion. MIRU-VNTR genotyping revealed a low clustering rate with a low recent transmission rate of M. tuberculosis strains in Alexandria, Egypt.

Water and oil-resistant paper materials based on sodium alginate/hydroxypropyl methylcellulose/polyvinyl butyral/nano-silica with biodegradable and high barrier properties

Despite many technical challenges in the development of safe and environmentally friendly food packaging paper materials with excellent water and oil resistance using simple methods, producing paper-based functional materials using bio-based polymers is currently an important topic in the food packaging industry. In this study, novel water and oil-resistant coatings for the paper were developed through the combination of sodium alginate (SA), hydroxypropyl methylcellulose (HPMC), polyvinyl butyral (PVB), and hydrophobic silica nanoparticles (HSNPs). To impart oil-repellency to paper, SA and HPMC were first mixed uniformly and coated on the base paper, which was pre-treated with calcium chloride solution. A compact and tough coating layer was formed on paper due to the hydrogen bonding between SA and HPMC molecules, and the crosslinking between SA and Ca2+ ions in the base paper. High water resistance of the paper was achieved through the coating of PVB and HSNPs on top of the coating of SA/HPMC. The final coated paper demonstrated outstanding oil resistance (kit rating: 12/12), water resistance (Cobb value: 4.23 g/m2), low water vapor transmission rate (100 g/m2·24 h), and improved mechanical properties. This fluorine-free, and biodegradable barrier paper will find excellent applications in the food packaging industry.

Morphea overlapping borderline leprosy: An unusual association

Leprosy, or Hansen’s disease, is a chronic infectious disease with a low transmission rate, affecting the skin, peripheral nerves, eyes, and mucous membranes of the upper respiratory tract, yet it may also be systemic. Cases of borderline leprosy are the acute or subacute stages of the disease. They are immunologically unstable and reflect the gradual variation in resistance against the etiological agent. Localized scleroderma or morphea is a fibrosing disease of the skin and underlying tissues that results from the disrupted function of growth factors (platelet-derived growth factor, i.e., PDGF) and receptor expression (as in the case of transforming growth factor b, i.e., TGF-b). Herein, we report a female patient with borderline tuberculoid leprosy (BT) who, during multidrug treatment (MDT), developed an indurated lesion of morphea exactly on the surface of an infiltrated patch.

A novel hybrid seed production technology based on a unilateral cross-incompatibility gene in maize.

Hybrid seed production technology (SPT) using genic recessive male sterility is of great importance in maize breeding. Here, we report a novel SPT based on a maize unilateral cross-incompatibility gene ZmGa1F with an extremely low transgene transmission rate (TTR). Proper pollen-specific ZmGa1F expression severely inhibits pollen tube growth leading to no fertilization. The maintainer line harbors a transgene cassette in an ipe1 male sterile background containing IPE1 to restore ipe1 male fertility, ZmGa1F to prevent transgenic pollen escape, the red fluorescence protein encoding gene DsRed2 for the separation of male sterile and fertile seeds, and the herbicide-resistant gene Bar for transgenic plant selection. When the maintainer line is selfed, gametes of ipe1/transgene and ipe1/- genotypes are produced, and pollen of the ipe1/transgene genotype is not able to fertilize female gametes due to pollen tube growth inhibition by ZmGa1F. Subsequently, seeds of ipe1/ipe1 and ipe1/transgene genotypes are produced at a 1:1 ratio and could be separated easily by fluorescence-based seed sorting. Not a single seed emitting fluorescence is detected in more than 200,000 seeds examined demonstrating that the pollen-tube-inhibition (PTI)-based TTR is lower than what has been reported for similar technologies to date. This PTI-based SPT shows promising potential for future maize hybrid seed production.

PSXIII-7 Field Testing of Lora-wan Sensors for Real-Time Tracking and Biosensing of Brangus and Raramuri Criollo Cattle Grazing a Small Pasture

Abstract The study’s objective was to investigate the use of Internet of Things (IoT) biosensors using Long Range Wide Area Network (LoRa-WAN) communication to compare the foraging behavior of two desert adapted cattle breeds. Two groups of mature Brangus (BA) and Raramuri Criollo (RC) cows were introduced into a small irrigated pasture (38ha) at the New Mexico State University’s Clayton Livestock Research Center during Dec-Jan, 2021 (41-days). The real-time position and activity count data (15- and 1-minute interval, respectively) were retrieved continuously from 4 BA and 5 RC cows collared with commercially available trackers (Abeeway Industrial-trackers). Response variables derived from GPS records included daily distance traveled (Dist) and daily area explored (Area). Response variables derived from accelerometers included daily percentage motion (%Act) and cumulative activity data (CumAct). All variables were grouped into six consecutive weekly periods and analyzed by a repeated measures mixed model that included the fixed effects of BREED, WEEK, and the BREED*WEEK interaction in a completely randomized design. A significant (P< 0.01) BREED*WEEK interaction was detected on all GPS-derived variables, with RC exhibiting a trend to explore larger areas than BA (P=0.06). For the accelerometer-derived variables, the BREED*WEEK interaction was only significant (P=0.01) for CumAct. Overall, BA spent a larger percentage of the day active (%Act; BA= 76.74 vs. RC= 73.16; P=0.02), while investing a significantly greater overall activity (CumAct; BA= 8816.63 vs. RC= 6311.31; P=0.03) compared to RC cows. The insensitivity of GPS-derived variables is hypothesized to be the result of aggregating errors associated with less frequent GPS location measurements coupled with position errors (~5m) and a low success rate of data packet transmission (~40%). The spatial scale of the study is hypothesized to have influenced the foraging behavior differences that were observed between the breeds, and the better performance of the accelerometer vs. GPS-derived variables.

Factors associated with antiretroviral therapy use among pregnant women in rural and urban settings in Southern Province, Zambia: 2016-2019.

To assess antiretroviral therapy (ART) coverage among pregnant women living with HIV and compare the characteristics of women who received and did not receive ART during pregnancy in Zambia. A cross-sectional study was conducted at urban and rural health facilities in Southern Province, Zambia, from 2016 to 2019. Pregnant women living with HIV delivering at study sites were enrolled and administered a questionnaire, and the results of infant diagnostic testing for HIV at birth was documented. About 1184 mother/infant pairs were enrolled. ART coverage was 93.7%. Most women who did not receive ART during pregnancy reported HIV diagnosis at delivery (18.0%) or during pregnancy (57.7%). The primary reported reason for not receiving ART was not wanting to take the drugs. Women who did not receive ART during pregnancy were significantly younger, less likely to have disclosed their HIV-infection status to others, and less likely to have received antenatal care than women who received ART. ART use correlated with higher levels of education in urban but not rural sites. Overall, 1.0% of infants were infected with HIV at birth, including 0.8% of infants born to women who received ART and 4.1% of infants born to women who did not. Most women received ART according to guidelines, resulting in low perinatal transmission rates of HIV to infants. Efforts to increase ART coverage and prevent vertical transmission should focus on identifying incident HIV infections during pregnancy and strengthening counselling for newly diagnosed pregnant women.

Synthesis and characterization of nanofibrilated cellulose films modified with blocked isocyanates in aqueous media and their barrier properties to water vapor and oxygen

Hydrophobic nanofibrilated cellulose (NFC) films were prepared by the casting of a mixture of NFC suspension in an aqueous emulsion of two blocked isocyanates - one prepared by the reaction of 4,4′- methylenebis (phenyl isocyanate) and phenol (MDI-2Ph) and a commercial one from trimethylol propane and toluene diisocyanate (Desmodur AP Stabil®) (TMP-TDI-3Ph),). The drying procedure was performed in two steps, i.e., first at 60 °C for 24 h and then at 170 °C for 10 min. Infrared spectroscopy (FT-IR), elemental analysis, and 13 CNMR confirmed the chemical modification of cellulose. The NFC modified films showed an approximately 40 g m−2.day−1 water vapor transmission rate, which is almost 75% lower than that of non-modified NFC films (153 g m−2.day−1). The film modified with TMP-TDI-3Ph showed a very low oxygen transmission rate and lower than that with MDI-2Ph When exposed to a wet environment, the modified films maintained their stiffness with Young's modulus around 5 GPa, whereas that of non- modified films decreased from approximately 6.5 GPa to below 0.1 GPa.

Hierarchically porous composite fabrics with ultrahigh metal–organic framework loading for zero-energy-consumption heat dissipation

The long-term safe operation of high-power equipment and integrated electronic devices requires efficient thermal management, which in turn increases the energy consumption further. Hence, the sustainable development of our society needs advanced thermal management with low, even zero, energy consumption. Harvesting water from the atmosphere, followed by moisture desorption to dissipate heat, is an efficient and feasible approach for zero-energy-consumption thermal management. However, current methods are limited by the low absorbance of water, low water vapor transmission rate (WVTR) and low stability, thus resulting in low thermal management capability. In this study, we report an innovative electrospinning method to process hierarchically porous metal–organic framework (MOF) composite fabrics with high-efficiency and zero-energy-consumption thermal management. The composite fabrics are highly loaded with MOF (75 wt%) and their WVTR value can be up to 3138 g m−2 d–1. The composite fabrics also exhibit stable microstructure and performance. Under a conventional environment (30 ℃, 60% relative humidity), the composite fabrics adsorb water vapor for regeneration within 1.5 h to a saturated value Wsat of 0.614 g g−1, and a corresponding equivalent enthalpy of 1705.6 J g−1. In the thermal management tests, the composite fabrics show a strong cooling capability and significantly improve the performance of thermoelectric devices, portable storage devices and wireless chargers. These results suggest that hierarchically porous MOF composite fabrics are highly promising for thermal management of intermittent-operation electronic devices.

Sensor-integrated biocomposite membrane for food quality assessment

The use of biopolymers is gaining momentum owing to their compatibility with various food commodities and acceptability by the industry and consumers. Biopolymers integrated with natural pigments can be used for assessing the quality of perishable packaged food products. Here, a biodegradable composite membrane of starch and chitosan, integrated with anthocyanin has been developed. The chromogenic response of the developed biocomposite membrane was used to assess spoilage in milk. The surface roughness recorded using atomic force microscopy and scanning electron microscopy showed smooth membrane surface, and a pore size 4.21 nm was determined by Brunauer-Emmett-Teller analysis. The water vapour transmissibility of the membrane was 4.616E-09 and 1.147E-08 g/h Pa.mm and water solubility was 5.6 and 5.8 % at 25 and 37 ℃, respectively, indicating high water resistance and low vapour transmission rate. The developed biocomposite membrane offers an environment friendly substrate for biosensing with a promising potential in smart food-packaging applications.

310.9: Ultra-Short Duration Pangenotypic Direct Acting Anti-viral Prophylaxis to Prevent Virus Transmission From Hepatitis C Viremic (HCV) Donors to Hepatitis C Negative Kidney Transplant Recipients

Purpose: Previous studies have shown that HCV D+/R- kidney transplantation is feasible using 8-12 weeks of DAAs. Utilization of abbreviated regimens may obviate the need for insurance approval and delay in therapy. We have previously shown very low transmission rates with a prophylactic peri-operative 7-day DAA (Sofusbuvir/Velpatasvir; SOF/VEL) regimen for ‘kidney-only’ transplants. Ezetimibe, a cholesterol lowering drug, has been shown to restrict HCV entry in hepatocytes in a humanized mouse model. Two published studies suggest that ezetimibe may be synergistic in reduction of HCV transmission from donors to recipients. Here we report our extended experience on 115 D+/R- kidney transplants with or without the addition of ezetimibe to the prophylactic regimen to investigate this effect. Methods: Data were collected via an Ethics Board approved prospective registry (REFORMHEPC). Inclusion criteria included: a) De-novo transplant; b) cPRA ≤50%; c) absence of synthetic liver dysfunction; and c) absence of active viral hepatitis. The primary outcome was donor HCV transmission at 90 days post-transplant. Patients were screened with HCV NAT at Day 7, 14, 28 and 90 post-transplant. All subjects received an initial dose of sofosbuvir/velpatasvir (SOF/VEL) +/- ezetimibe on day 0 ≤6 hours prior to transplant and then daily for a total of 7 days. Immunosuppression included induction with rabbit anti-thymocyte globulin followed by maintenance tacrolimus, mycophenolate and steroids. The protocol mandated initiation of full-course DAA therapy in case of 2 consecutive positive NAT tests. Results: A total of 115 D+/R- transplants (mean age=56 yrs) were included from May 2019-August 2021. The distribution of patients across the two groups was Group 1 (7 days prophylaxis with SOF/VEL alone; N=32) and Group 2 (7d prophylaxis with SOF/VEL plus ezetimibe; N=83). Patients enrolled in the two groups were demographically similar. Five patients (5/115; 4.3%; 95%CI:2%-10%) developed HCV viremia [1/32 (3%) in group 1, and 4/83 (4.8%) in group 2]. The donor genotypes (GT) are as follows: 3/5 (60%) GT3; 1/5 (20%) GT1b; 1/5 (20%) GT2b. All 5 patients with HCV transmission achieved SVR with 12 weeks of Glecapravir/Pibrentasvir therapy. Conclusions: In this ‘largest-in-world’ series, the data suggests that 7-days ultra-short duration pan-genotypic SOF/VEL prophylaxis is safe and largely effective in preventing donor-derived HCV transmission and has the potential of resulting in significant cost-savings by avoiding longer DAA therapy in a large majority of D+/R- KT. The addition of ezetimibe did not appear to provide any additional benefit in preventing HCV viral transmission.

GAN for Load Estimation and Traffic-Aware Network Selection for 5G Terminals

In the face of the user-centric access network architecture adopted by the fifth-generation (5G) mobile communication network terminals, the communication capability of terminals faces significant challenges. In this case, the combination of 5G and artificial intelligence (AI) has become a significant trend to meet the various communication needs of terminal devices. Toward the problem that the data analysis and decision making for cell load estimation are primarily accomplished on the access side of the network, terminals can only passively access the network, but cannot predict the load estimation on the access side of the network in advance and cannot make network selection decisions in real time. In this article, we propose a cell load estimation algorithm based on a generative adversarial network (GAN) for 5G mobile communication networks, which considers estimating the cell load according to the wireless information measured by the terminals. The algorithm effectively estimates the cell load at the terminal side, which reflects the intelligence of the terminals and solves the problems of low data transmission rate, high signaling cost, and time delay in the existing techniques for load estimation schemes at the network side, assisting users in making a real-time decision. The performance is evaluated through the system-level simulation, and the results indicate that the proposed model improves load estimation accuracy, simultaneously improving the network throughput and reducing the packet queuing delay, suitable for different heterogeneous network scenarios.

Optimal Allocation Method of 5G Communication System Resources Assisted by Artificial Intelligence Technology

5G technology has been rapidly developed under the trend of utilization in various countries. It is an information dissemination technology with faster and more stable transmission speed. Compared with 4G technology, 5G technology has a low delay rate and higher transmission speed, and it can be applied in tasks such as the Internet of Vehicles and the transmission of 3D images. For 5G technology, the communication system is a huge challenge. It not only needs to deal with the transmission speed between users and users but also needs to deal with the efficiency between users and channels. 5G researchers will spend a lot of material and financial resources to solve these problems. This study uses artificial intelligence technology to analyze its application in resource allocation of 5G communication systems. It also uses the collaborative filtering algorithm to realize the automatic recommendation and matching problem of 5G communication system resources. The research results show that artificial intelligence technology has good feasibility in the resource allocation problem of 5G communication system. It can achieve the resource allocation task of 5G technology communication system with high efficiency and accuracy, and all prediction errors are within 3% for the characteristics of the three 5G communication systems in this study.

Non-Reconciled Physical-Layer Keys-Assisted Secure Communication Scheme Based on Channel Correlation.

Physical-layer key generation technology requires information reconciliation to correct channel estimation errors between two legitimate users. However, sending the reconciliation signals over the public channel increases the communication overhead and the risk of information leakage. Aiming at the problem, integrated secure communication schemes using non-reconciled keys have attracted extensive attention. These schemes exploit channel coding to correct both inconsistent keys and transmission error bits. Meanwhile, more redundant code bits must be added to correct errors, which results in a lower secure transmission rate. To address the problem, we analyze the merit of channel correlation between non-reconciled key generation and secure transmission. Inspired by this, we propose a non-reconciled physical-layer keys-assisted secure communication scheme based on channel correlation. First of all, the signal frame is designed to make use of channel correlation between non-reconciled key generation and secure transmission. Based on the channel correlation, non-reconciled keys are then generated from the wireless channel to encrypt transmitted data. Moreover, an adaptive coding algorithm based on the equivalent channel is presented to encode the data bits before encryption, to guarantee reliable transmission. Finally, theoretical analysis and simulations demonstrate the significant performance of the proposed scheme in terms of low bit error ratio and high secure transmission rate.

Stretchable and Fast Composting Polyester Films with High-Performance Oxygen Barrier

This work presents one of the fastest composting aliphatic–aromatic polyesters with a good balance of mechanical and barrier properties, making it a sustainable alternative for low-density polyethylene in packaging. The polyesters (PBxBDMyS) are prepared by melt polycondensation of 1,4-butanediol (B), 1,4-benzenedimethanol (BDM), and succinic acid (S). One composition exhibited a tensile strength of 20 ± 2 MPa, a modulus of 150 ± 8 MPa, and a very high elongation at break of 581 ± 46%. The low oxygen transmission rate (152 cm3·m–2·day–1·bar–1) measured at 65% relative humidity and 23 °C confirms excellent barrier performance. A 3 μm water-borne nanocomposite coating of glycol chitosan and sodium fluorohectorite further reduced the gas permeability to a value of 0.75 cm3·m–2·day–1·atm–1, which is competitive with materials suitable for demanding packaging applications such as poly(vinylidene chloride) while maintaining good mechanical properties and high stretchability. After studying the enzyme-catalyzed hydrolysis under controlled conditions, the full fragmentation, assimilation, and mineralization in thermophilic, aerobic composting could be confirmed in less than 5 weeks using a combination of different analytical methods. The mechanism of degradation was proven to be bulk degradation.

24 loci MIRU-VNTR analysis and pattern of drug resistance in pre-extensively drug resistant pulmonary tuberculosis in Bangladesh.

Phylogenetic diversity and distinct phylogeographic distribution of Mycobacterium tuberculosis (MTB) contribute to regional differences in drug resistance. The emergence of pre-extensively drug resistant tuberculosis (Pre-XDR-TB) becomes obstacles to achieve End TB strategy in Bangladesh. This cross-sectional study was conducted to identify the strains of different lineages of MTB, their variations of distribution among Pre-XDR-TB cases and to observe the linkage of particular strains of MTB with drug resistance. A total of 33 Pre-XDR-TB isolates were enrolled in this study. All isolates were confirmed as MTB by MPT 64 antigen detection and genotyped by 24 loci Mycobacterial Interspersed Repetitive Unit-Variable Number of Tandem Repeats (MIRU-VNTR) analysis. Drug resistance was detected by second line Line probe assay (LPA). Beijing was the predominant strain 16 (48.48%), followed by Delhi/CAS 5(15.15%), LAM 4 (12.12%) and Harlem 3(9.10%), EAI 2(6.06%), Cameroon 2(6.06%) and NEW-1 1(3.03%). There were 31 different genotypes consisting of 2 clusters and 29 singletons. All the clustered strains were belonged to Beijing lineage. Recent transmission occurred manly by Beijing strains, showed low transmission rate (12.1%). Of 33 isolates 30(90.90%) were Fluoroquinolones resistant, the mutations involved was Asp94Gly in gyr A MUT 3C gene 13(39.39%) in quinolone resistance determining region (QRDR) followed by 11 (33.33%) in gyr A MUT 1. Three (9.10%) isolates showed resistant to injectable 2nd line drugs and all mutation occurs in G1484T of rrs MUT 2. Beijing lineage was predominant in treatment failure and relapse cases. Levofloxacin was resistant to all Pre-XDR-TB cases, but moxifloxacin showed low level resistance. QUB 26 was the most discriminatory locus (0.85) among 24 loci whereas MIRU 2 was the least (0.03). 24 loci MIRU-VNTR analysis shows high discriminatory index (0.71), found to be powerful tool for genotyping of Pre-XDR-TB, which is the first study in Bangladesh that enhanced the current TB control policy.

Low transmission rates of Equine infectious anemia virus (EIAV) in foals born to seropositive feral mares inhabiting the Amazon delta region despite climatic conditions supporting high insect vector populations

BackgroundMarajó Island, within in the Amazon River Delta, supports numerous bands of feral equids including the genetically distinct Marajoara horses. Approximately 40% of the equids on the island are infected with Equine infectious anemia virus (EIAV). This high seropositivity rate coupled with the need to preserve rare breeds such as the Marajoara horse precludes euthanasia as the primary means for controlling EIAV in this region. In the absence of iatrogenic transmission, spread of this lentivirus is mediated primarily by hematophagous insects, whose year-round prevalence on the island is supported by favorable climatic conditions. In addition, cases of vertical EIAV transmission have been observed suggesting inclusion of seropositive mares in restorative breeding programs could result in their progeny becoming infected with this virus either pre-parturition or post-partum via hematophagous insects. Therefore, the aim of this study was to evaluate EIAV vertical and post-partum insect-mediated transmission rates among foals born to seropositive feral mares until natural weaning. Serum samples from foals born to seropositive feral mares within the Soure municipality, of Marajó Island, were collected to investigate their serological status, using an indirect ELISApgp45, with positive samples confirmed using the classical agar gel immunodiffusion (AGID) assay.ResultsThe serological status of 28 foals were monitored over a 2-year period with some subjects, depending on their date of birth, being sampled up to six times. All foals remained with their respective mares until fully weaned at approximately 10 months of age. Only 2 foals (7.14%) in the study group became seropositive against EIAV.ConclusionThe results demonstrate that in most cases it is possible to obtain seronegative foals born to and eventually weaned by EIA positive mares, even in equatorial regions where substantial rainfall and high temperatures favor the proliferation of insect vectors.

Quantization Framework for Fast Spiking Neural Networks.

Compared with artificial neural networks (ANNs), spiking neural networks (SNNs) offer additional temporal dynamics with the compromise of lower information transmission rates through the use of spikes. When using an ANN-to-SNN conversion technique there is a direct link between the activation bit precision of the artificial neurons and the time required by the spiking neurons to represent the same bit precision. This implicit link suggests that techniques used to reduce the activation bit precision of ANNs, such as quantization, can help shorten the inference latency of SNNs. However, carrying ANN quantization knowledge over to SNNs is not straightforward, as there are many fundamental differences between them. Here we propose a quantization framework for fast SNNs (QFFS) to overcome these difficulties, providing a method to build SNNs with enhanced latency and reduced loss of accuracy relative to the baseline ANN model. In this framework, we promote the compatibility of ANN information quantization techniques with SNNs, and suppress “occasional noise” to minimize accuracy loss. The resulting SNNs overcome the accuracy degeneration observed previously in SNNs with a limited number of time steps and achieve an accuracy of 70.18% on ImageNet within 8 time steps. This is the first demonstration that SNNs built by ANN-to-SNN conversion can achieve a similar latency to SNNs built by direct training.

Hybrid error correction in fragmented IoT media streams

AbstractWireless personal area networks (WPANs), as most IoT networking technologies, rely on constrained low power devices that support a trade‐off between signal coverage and transmission rates. WPANs are characterized for medium to low transmission rates over low distances. The transmission rates, however, are high enough to support maximum transmission unit (MTU) sizes that are large enough to enable the transmission of IPv6 datagrams. One such WPAN technologies is associated with the IEEE 802.15.4 physical layer. Because IEEE 802.15.4 does not natively support IP encapsulation, an adaptation mechanism known as IPv6 over low‐power wireless personal area networks (6LoWPAN) is used to this end. For large datagrams like those generated when transmitting speech frames, 6LoWPAN fragments them in order to comply with the 127‐byte IEEE 802.15.4 MTU size. Fragmentation, however, aggravates the effects of network packet loss. This article explores this problem and attempts to find a mechanism that overcomes these limitations. Specifically, it introduces a hybrid error correction algorithm that dynamically adjusts the number of fragments that are transmitted in order to balance application layer loss and transmission rate.

Double-Stream Differential Chaos Shift Keying Communications Exploiting Chaotic Shape Forming Filter and Sequence Mapping

A new Differential Chaos Shift Keying modulation scheme exploiting Chaotic Shape-forming Filter and Sequence Mapping (CSF-SM-DCSK) is being proposed. The new CSF-SM-DCSK system employs a novel sequence mapping rule and includes a data correction module to achieve a good trade-off between the low Bit Error Rate (BER) performance and high transmission rate. It transmits two data streams simultaneously and preserves the simplicity and robustness of DCSK method. Channel one, transmitting a Low Priority Stream (LPS), generates the chaotic carrier by a Chaotic Shape-forming Filter (CSF) at the transmitter and applies a coherent Matched Filter (MF) at the receiver to recover the information. Channel two, transmitting a High Priority Stream (HPS), relies on conventional DCSK modulation, while the reference and information-bearing parts are transmitted simultaneously with orthogonal sine and cosine carriers. This double-stream solution eliminates the need for analog RF delay lines and doubles the data transmission rate. Before feeding the LPS data stream into the modulator, each LPS bit is encoded into a symbol sequence using sequence mapping. This approach, together with the coherent MF reception, equips the LPS channel with an extremely high robustness against channel noise and multipath propagation. To handle every possible redundancy in the received signal and to minimize the possibility of making wrong decisions, a data correction block is also introduced. Initially, a rough estimation of the received HPS DCSK bit is done at the receiver, then this estimation is used to remove the DCSK modulation from the received information-bearing signal. The three inputs of data correction blocks are: (i) the reference and (ii) the information-bearing parts of the received signal in their original form, and (iii) the received information-bearing signal where the DCSK modulation is removed. The data correction block improves the BER performance while the increased channel capacity, enabled by the double-stream approach, improves the spectral efficiency. Analytical expressions are derived to predict the BER performances in additive white Gaussian noise channel for both the LPS and HPS channels. Computer simulations are used to show that the system performance of the CSF-SM-DCSK modulation scheme proposed in this work is superior to that of the already published solutions. In addition to the computer simulations, the new chaos-based wireless communications system has been implemented on a wireless open-access research platform to experimentally demonstrate the feasibility and the superiority of CSF-SM-DCSK.

Transmission of Grapevine Ampelo- and Vitiviruses by the Bohemian Mealybug Heliococcus bohemicus Šulc (Hemiptera: Pseudococcidae).

Grapevine-infecting ampelo- and vitiviruses are transmitted by several scale insect species, including the Bohemian mealybug, Heliococcus bohemicus Šulc. Virus infectivity experiments were performed with this species to study the transmission ability of natural populations living in infected vineyards in Alsace, France. Mealybugs were sampled on vines infected by grapevine leafroll-associated viruses (GLRaV-1, -2, and -3) and by grapevine virus A (GVA), either alone or in combinations. Out of six natural populations tested, only one, located at Bennwihr, was able to transmit GLRaV-1 and -3 to healthy vines, though with low transmission rates (1.6 and 11.8%, respectively). Mealybugs from Bennwihr were also able to transmit GLRaV-3 from grapevines of another location where H. bohemicus was not a vector. Conversely, mealybugs from two other locations did not transmit any virus acquired from infected grapevines at Bennwihr. These results suggest differences in vector ability between H. bohemicus populations. Moreover, laboratory experiments were developed to estimate the minimal acquisition and inoculation access periods (AAP and IAP, respectively) for virus transmission of GLRaV-1 and -3, and GVA. First instar nymphs transmitted GLRaV-1 after 6 h AAP, GLRaV-3 and GVA together after 1 h AAP, and the three viruses after only 1 h IAP, supporting a semi-persistent mode of transmission. Second instar nymphs fed on multi-infected grapevine for 72 h then starved or fed on potatoes tested positive by RT-PCR for GLRaV-1 and -3 after up to 35 and 40 days, respectively, contrasting with the short retention times generally observed for mealybugs. These findings provide new knowledge of the vector ability of H. bohemicus.