Variable Resistance Research Articles

Evidence of the Transmission of Resistance of Enterobacteria to Betalactamines Between Mothers and Children in Brazzaville

Beta-lactams have always been used in many cases as first-line antibiotics in human medicine. The emergence of beta-lactamase-producing strains of Enterobacteriaceae is nowadays a public health problem. In order to demonstrate the transplacental transmission of enterobacteria resistance to beta-lactams between mothers and their children. Seventy-two (72) stool samples were collected from mothers and two-day-old newborns at the Talangaï referral hospital. Isolation of enterobacteria was done on selective media. Identification of beta-lactamase producing strains was performed by biochemical characteristics using API 20E strips. The resistance profile to carbapenems, monobactam and cephalosporins was performed by antibiogram. A total of 50 strains were purified and identified, of which 30 (60%) were isolated from the mother-newborn couple and 20 (40%) from the newborns. Among these strains, we identified in the mother-newborn group: 10 (33%) <i>Enterobacter </i>sp, 10 (33%) <i>Escherichia coli</i>, 6 (20%) <i>Klebsiella</i> oxytoca; 2 (7%) <i>Shigella </i>sp and 2 (7%) <i>Salmonella</i> sp. High resistance to carbapenems and cephalosporins was observed with <i>Shigella</i> sp. The other strains of enterobacteria isolated from newborns only, among which were identified: 7 (35%) <i>Escherichia coli</i>; 5 (25%) Klebsiella oxytoca; 5 (25%) <i>Enterobacter </i>sp, 3 (15%) <i>Shigella</i> sp. newborns without their mothers showed a variable resistance profile to the antibiotics tested. Three resistance phenotypes were observed in the mother-newborn group including: FEP PRL CL, FEP AMP MA CR ATM IMP ETP and FEP AMP CAZ MA CL ETP. The resistance phenotypes observed in the mothers were identical to those found in their respective offspring. These results show that each newborn is born with a rate of resistance acquired at birth, which testifies to a transplacental transmission between mother and child, consequence of the emergence of the resistance of enterobacteria to betalactamines in the Congolese population.

Molecularly Imprinted Polymers: Promising Tool for the Human Virus Detection

Molecular imprinting is an attractive research area for synthesizing unique functional polymers with high selectivity due to template oriented active sites. Molecularly imprinted polymers (MIPs) have a wide range of applications in chemical and biological sensing, drug delivery, and solidphase extraction owing to mechanical stability, reversibility, reproducibility, and cross-validity. MIPs are compatible with natural antibodies and are being used as antibody mimics/receptors in the biomedical field. Today, viral detection is the most popular research area due to emerging viral diseases with genetic variability and drug resistance. Therefore, there is a need to control viral infections by discriminative recognition of the viral pathogens. This review summarizes the literature on the detection of human viruses by using MIPs.

Comparison of Methods for Determining the Antibiotic Susceptibility of Aerococcus Species in a Clinical Setting.

Aerococcus spp are Gram-positive cocci increasingly recognized as uropathogens. The Clinical and Laboratory Standards Institute recently published specific breakpoints for Aerococcus spp (M45, third edition); however, the standardized method used for antimicrobial susceptibility testing (AST) requires media not often maintained in clinical laboratories. The purpose of this study was to evaluate and compare alternative methods of AST for Aerococcus isolates. AST was performed on 134 clinical isolates using the Etest on three different types of agar, Vitek 2, and BD Phoenix. These results were compared with broth microdilution using the Sensititre STP6F. Aerococcus exhibited low minimum inhibitory concentrations to benzylpenicillin, meropenem, linezolid, and vancomycin. Variable resistance was seen to levofloxacin, ceftriaxone, and tetracycline. Meropenem and vancomycin met all acceptance criteria with every alternative method tested. Benzylpenicillin and linezolid did not meet essential agreement on any AST method. Tetracycline met the majority of acceptance criteria with the exception of more than 3% very major error when using the Etest on chocolate agar, the Vitek 2, and BD Phoenix. Overall, the alternate AST method with the highest agreement with broth microdilution was the Etest on Mueller-Hinton agar with 5% sheep blood and may be an optimal alternative to broth microdilution.

Resistive Memory Devices Based on Reticular Materials for Electrical Information Storage.

Recently, reticular materials, such as metal-organic frameworks and covalent organic frameworks, have been proposed as an active insulating layer in resistive switching memory systems through their chemically tunable porous structure. A resistive random access memory (RRAM) cell, a digital memristor, is one of the most outstanding emergent memory devices that achieves high-density electrical information storage with variable electrical resistance states between two terminals. The overall design of the RRAM devices comprises an insulating layer sandwiched between two metal electrodes (metal/insulator/metal). RRAM devices with fast switching speeds and enhanced storage density have the potential to be manufactured with excellent scalability owing to their relatively simple device architecture. In this review, recent progress on the development of reticular material-based RRAM devices and the study of their operational mechanisms are reviewed, and new challenges and future perspectives related to reticular material-based RRAM are discussed.

New Applications of Photodynamic Therapy in the Management of Candidiasis.

The most important aetiological agent of opportunistic mycoses worldwide is Candida spp. These yeasts can cause severe infections in the host, which may be fatal. Isolates of Candida albicans occur with greater frequency and variable resistance patterns. Photodynamic therapy (PDT) has been recognised as an alternative treatment to kill pathogenic microorganisms. PDT utilises a photosensitizer, which is activated at a specific wavelength and oxygen concentration. Their reaction yields reactive oxygen species that kill the infectious microorganism. A systematic review of new applications of PDT in the management of candidiasis was performed. Of the 222 studies selected for in-depth screening, 84 were included in this study. All the studies reported the antifungal effectiveness, toxicity and dosimetry of treatment with antimicrobial PDT (aPDT) with different photosensitizers against Candida spp. The manuscripts that are discussed reveal the breadth of the new applications of aPDT against Candida spp., which are resistant to common antifungals. aPDT has superior performance compared to conventional antifungal therapies. With further studies, aPDT should prove valuable in daily clinical practice.

Protein kinase RNA-activated controls mitotic progression and determines paclitaxel chemosensitivity through B-cell lymphoma 2 in ovarian cancer.

Anti-tubulin agents, such as paclitaxel, have been used extensively for treatment of several types of cancer, including ovarian, lung, breast, and pancreatic cancers. Despite their wide use in cancer treatment, however, patient response is highly variable and drug resistance remains a major clinical issue. Protein kinase RNA-activated (PKR) plays a critical role in immune response to viral infection. We identified PKR as a phospho-protein in response to anti-tubulin agents and this phosphorylation occurs independent of its own kinase activity. PKR is phosphorylated by cyclin-dependent kinase 1 (CDK1) during anti-tubulin treatment and unperturbed mitosis and that PKR regulates mitotic progression in a phosphorylation-dependent manner. Furthermore, inactivation of PKR confers resistance to paclitaxel in ovarian and breast cancer cells in vitro and in vivo. PKR expression levels and activity are decreased in chemotherapeutic recurrent ovarian cancer patients. Mechanistically, our findings suggest that PKR controls paclitaxel chemosensitivity through repressing Bcl2 expression. Pharmacological inhibition of Bcl2 with FDA-approved agent venetoclax overcomes paclitaxel resistance in preclinical animal models of ovarian cancer. Our results suggest that PKR is a critical determinant of paclitaxel cytotoxicity and that PKR-Bcl2 axis as a potential therapeutic target for the treatment of recurrent drug-resistant ovarian tumors.

Characterization of probiotic lactobacilli and development of fermented soymilk with improved technological properties

Two human-originated bacterial strains Limosilactobacillus reuteri NCDC958 and Lacticaseibacillus rhamnosus NCDC953, previously characterized as extracellular B12-producers, were tested in the current study for the in vitro probiotic potential, and for the development and technological characterization of probiotic fermented soymilk. During in vitro probiotic testing, both strains showed 1.6 to 2.2 log reduction at pH 3, tolerate 0.3% bile salt, exhibited auto- (36–47%) and co-aggregation features (28–32%), along with moderate hydrophobicity (26–63% for xylene, ethyl acetate, and chloroform) and noticeable (≥13 mm inhibition zone) antimicrobial activity against food-related pathogenic indicators (Escherichia coli, Bacillus cereus, Salmonella typhimurium, Enterococcus faecalis, Staphylococcus aureus). Both cultures lacked hemolytic activity and showed variable susceptibility and resistance towards clinical antibiotics. The addition of 0.1% modified starch and 1% vanilla flavor improved sensory, rheological and textural properties of both the fermented soymilks with final acceptability above 7 on a 9-point hedonic scale. No significant differences (P > 0.05) were observed in acidity, pH, and microbiological counts. According to obtained results, fermented soymilks developed using probiotic strain NCDC958 or NCDC953 were found satisfactory on all technological and sensorial attributes under evaluation and may be forwarded for scale-up fermentation.

MORPHO-AGRONOMIC, CYTOGENETIC AND MOLECULAR CHARACTERIZATION OF SYNTHETIC WHEAT ACCESSIONS AS A POTENTIAL GERMPLASM FOR PLANT BREEDING

Synthetic hexaploid wheat (AABBDD) is produced by using the tetraploid Triticum turgidum var. durum (AABB) and the diploid Aegilops tauschii (DD) as parents. This cross has allowed genetic variability to be transferred from parental to other wheat hexaploid accessions, lines or cultivars. This transference may occur not only of variable disease resistance genes but also traits involving quality and tolerance to abiotic stresses. We evaluated and characterized the genetic diversity and stability of synthetic wheat accessions that can be used in breeding programs due to the presence of desirable characteristics. Fifty synthetic accessions were investigated regarding their morphological and agronomic characteristics, presence of micronuclei in tetrads and genetic similarity based on molecular markers. Four commercial cultivars were used as controls. Depending on their proposed use, some genotypes were characterised as suitable for breeding programs based on their morphological traits, genetic stability or genetic diversity, or because of a combination of these factors.

Rotor Position Synchronization in Central-Converter Multi-Motor Electric Actuation Systems

The aerospace industry is increasingly transitioning from hydraulic and pneumatic drives to power-electronic based drive systems for reduced weight and maintenance. Electromechanical thrust reverse actuation systems (EM-TRAS) are currently being considered as a replacement for mechanical based TRAS for future aircraft. An EM-TRAS consists of one or more power-electronic drives, electrical motors, and gear-trains that extend/retract mechanical members to produce a drag force that decelerates the aircraft upon landing. The use of a single (“central”) power electronic converter to simultaneously control a set of parallel induction machines is a potentially inexpensive and robust method for implementing EM-TRAS. However, because the electrical motors may experience different shaft torques—arising from differences in wind forces and a flexible nacelle—a method to implement rotor position synchronization in central-converter multi-motor (CCMM) architectures is needed. This paper introduces a novel method for achieving position synchronization within CCMM architecture by using closed-loop feedback of variable stator resistances in parallel induction machines. The feasibility of the method is demonstrated in several case studies using electromagnetic transient simulation on a set of parallel induction machines experiencing different load torque conditions, with the central converter implementing both voltage-based and current-based primary control strategies. The key result of the paper is that the CCMM architecture with proposed feedback control strategy is shown in these case studies to dynamically drive the position synchronization error to zero. The initial findings indicate that the CCMM architecture with induction motors may be a viable option for implementing EM-TRAS in future aircraft.

Changing microbiological profile and antimicrobial susceptibility of the isolates obtained from patients with infective endocarditis – The time to relook into the therapeutic guidelines

The microbiological profile, associated risk factors and demographic characteristics of patients with IE has changed in the recent times. In the present study, the antibiotic susceptibility profile of 66 isolates (40 from IDU and 26 from non IDU) recovered over a period of three years from the patients with definitive diagnosis of IE along with their absolute minimum inhibitory concentrations (MIC-μg/ml) was determined as per CLSI, 2017 guidelines. Staphylococcus aureus was found to be the predominant pathogen associated with IE out of which 90.2% isolates were MRSA, although none of the isolates were found resistant to vancomycin, teicoplanin, daptomycin and linezolid. Pseudomonas aeruginosa isolates were 100% susceptible to carbapenams, however variable resistance was observed against other antimicrobials. All Enterococci were found to be 100% susceptible to linezolid and daptomycin, whereas vancomycin resistant enterococci phenotype was observed in 25% of the Enterococcal isolates. A noticeable difference in the antimicrobial susceptibility profile and their MICs were observed in the present study, as compared to published literature across the globe and within the country. However, no statistically significant difference (λ 2 test, p > 0.01)in the AST pattern of isolates from IDU vs. Non IDU was observed. After reviewing the local antibiogram it seems that we need to have our own regional guidelines, which may partially replace the currently prevailing AHA/ESC guidelines.

Characterization of ABH-subtype donor-specific antibodies in ABO-A-incompatible kidney transplantation

ABO‐incompatible (ABOi) transplantation requires preemptive antibody reduction; however, the relationship between antibody‐mediated rejection (AMR) and ABO‐antibodies, quantified by hemagglutination (HA), is inconsistent, possibly reflecting variable graft resistance to AMR or HA assay limitations. Using an ABH‐glycan microarray, we quantified ABO‐A antigen‐subtype (A‐subtype)‐specific IgM and IgG in 53 ABO‐O recipients of ABO‐A kidneys, before and after antibody removal (therapeutic plasma exchange [TPE] or ABO‐A‐trisaccharide immunoadsorption [IA]) and 1‐year posttransplant. IgM binding to all A‐subtypes correlated highly (R 2 ≥ .90) and A‐subtype antibody specificities was reduced equally by IA versus TPE. IgG binding to the A‐subtypes (II–IV) expressed in kidney correlated poorly (.27 ≤ R 2 ≤ .69). Reduction of IgG specific to A‐subtype‐II was equivalent for IA and TPE, whereas IgG specific to A‐subtypes‐III/IV was not as greatly reduced by IA (p < .005). One‐year posttransplant, IgG specific to A‐II remained the most reduced antibody. Immunostaining revealed only A‐II on vascular endothelium but A‐subtypes II‐III/IV on tubular epithelium. These results show that ABO‐A‐trisaccharide is sufficient for IgM binding to all A‐subtypes; this is true for IgG binding to A‐II, but not subtypes‐III/IV, which exhibits varying degrees of specificity. We identify A‐II as the major, but importantly not the sole, antigen relevant to treatment and immune modulation in adult ABO‐A‐incompatible kidney transplantation.

Multidrug resistance, biofilm formation, and virulence genes of Escherichia coli from backyard poultry farms.

Background and Aim:Backyard chicken flocks have traditionally been regarded as an essential food source in developed countries; however, they may act as reservoirs and spread various zoonotic bacterial pathogens. This study was designed to investigate the prevalence, phenotypic resistance, biofilm formation (BF), and pathotypes of Escherichia coli isolates from backyard poultry farms.Materials and Methods:Cloacal swabs (n=150) and internal organs (n=150) were collected from 30 backyard chicken flocks; 20 of them were experiencing systemic infection, and the other ten were apparently healthy. Samples were bacteriologically examined for E. coli isolation. Isolates were identified biochemically by the VITEK® 2 COMPACT system (BioMérieux, France). For molecular identification, 16S rRNA was amplified and sequenced. Ten antimicrobials were selected for E. coli antimicrobial susceptibility testing. The minimum inhibitory concentration for each antimicrobial was determined. The extended-spectrum β-lactamase activity in isolates was investigated using cephalosporin/clavulanate combination disks. The ability of isolates for BF was determined by the microtiter plate method. Thirteen virulence genes linked to different E. coli pathotypes and two serotype-related genes were investigated by real-time polymerase chain reaction.Results:Eighty-six E. coli strains were isolated from 30 backyard chicken flocks. The isolates were biochemically identified to the species level. Genetically, sequences of the 16S rRNA gene showed >98% identity with E. coli in the National Center for Biological Information database. The frequency of isolation from diseased flocks was significantly higher (p<0.05) than apparently healthy flocks; 63.9% of the isolates were recovered from cloacal swabs and 36.04% were recovered from internal organs. E. coli isolates showed high resistance to ampicillin (AMP; 75.6%), gentamicin (39.5%), and tetracycline (29.1%). However, none of the isolates were resistant to imipenem. A variable drug resistance profile for E. coli isolates was reported. Twenty-one (24.4%) isolates were sensitive to all ten antimicrobials. Seven (8.1%) isolates were resistant only to AMP, and 28 (32.6%) were resistant to two antimicrobials, whereas the remaining 30 (34.9%) isolates showed multidrug resistance (MDR). Of the 86 isolates, 8 (9.3%) were confirmed as extended-spectrum β-lactamase (ESBL)-producing E. coli by the combination disk diffusion method. All ESBL isolates were MDR with an MDR index of 0.5-0.6. Fifty-seven (66.3%) isolates were capable of forming biofilms; 22 (25.6%) of them were strong biofilm producers, 24 (27.9%) moderate producers, and 11 (12.8%) weak producers. A statistically significant pairwise correlation was obtained for MDR versus BF (r=0.512) and MDR index versus BF (r=0.556). Based on virulence gene profiles, five pathotypes were identified, including enteropathogenic E. coli (39.5%), avian pathogenic E. coli (32.53%), enterohemorrhagic E. coli (EHEC; 9.3%), enterotoxigenic E. coli (ETEC; 5.8%), and enteroaggregative E. coli (EAEC; 1.2%). The lower frequency of EAEC and ETEC was statistically significant than other pathotypes. Three isolates were identified as O157 based on the detection of the rbfO157 gene.Conclusion:This study reported a high prevalence of MDR, suggesting the misuse of antimicrobials in backyard chicken farms. The emergence of ESBL and EHEC isolates in backyard chickens is a public health concern. Furthermore, the backyard flocks environment may harbor different pathogenic bacteria that may enhance the persistence of infection and the transmission to in-contact humans. Regular monitoring for the occurrence of MDR and the zoonotic pathotypes among E. coli in backyard chicken flocks is recommended, as these bacteria can transmit to humans through food products or contaminated environments.

A Magnetic Reconfigurable Ternary NOR/NAND Logic for Logic-in-Memory Applications

Logic-in memory has emerged as a promising solution to reduce the significant time gap between processor and memory. Simple logics such as NOR and NAND can be embedded in the memory for the purpose of data processing. Besides, ternary logic has been suggested to reduce the interconnects and the complexity of operations. In this paper, a reconfigurable ternary NOR/NAND logic compatible with ternary memories has been proposed. This scheme exploits magnetic tunnel junction as a nonvolatile memory element and a variable resistance, and carbon nanotube field-effect transistor for designing the peripheral circuits to achieve performance and efficiency. The proposed circuit is simulated using HSPICE and the results have validated the correct operation and high performance of the proposed design. Furthermore, the proposed designs are exploited in image processing applications to evaluate their performance in real applications, which gain averagely 52% improvement in the case of data loss.

Estimation of the initial material of spring barley for adaptability to arid conditions of the Stavropol territory

Grain production stabilization is one of the main criteria for the development of agriculture in Russia. In this regard, in modern breeding, when developing varieties, considerable attention must be paid to their adaptability, i.e. parameters that ensure stable productivity in various growing conditions. The purpose of the current study was to estimate the spring barley samples according to the trait ‘yield’ for adaptability to the arid conditions of the Stavropol Territory and their further use in breeding work. The material for the study were 86 spring barley samples. In order to determine the stability, there was used a variance coefficient (V%) according to the method of B.A. Dospekhov (2014). The ecological adaptability (bi) and the environment index (Ij) were determined according to the method of S.A. Eberhart and W.A. Russell (1966) as presented by V.Z. Pakudin (1984). Homeostaticity (Hom) was assessed according to the method of V.V. Hangildin (1981). Stress resistance was determined according to the equations of A.A. Rosielle and J. Hamblin as presented by A.A. Goncharenko (2005). There were identified the highly productive samples ‘Mamlyuk’ (389 g/m2) and ‘Stirling’ (378 g/m2), possessing high responsiveness to improving environmental conditions (bi = 1.44–1.21), variability (V = 58.9–51,2%) and low stress resistance (Ymin – Ymax = -538–488). Such genotypes are capable of forming high yields in favorable conditions and may be of interest for breeding high-intensity varieties. The samples weakly responsive to changes in growing conditions were distinguished by high stability and homeostaticity according to the trait ‘yield’, namely ‘Nutans 74840’ (Hom = 2.88; V = 38.4%) and ‘Veles’ (Hom = 2.56; V = 38.5%), as well as the adaptable variety ‘Getman’ (Hom = 2.89; V = 40.6%). These samples are the most adaptive to the arid conditions of the Stavropol Territory and regions with similar cultivation conditions. They are recommended for use in breeding work.

Differential transcriptome analysis and identification of genes related to resistance to blight in three varieties of Bambusa pervariabilis × Dendrocalamopsis grandis

BackgroundBambusa pervariabilis × Dendrocalamopsis grandis is a fast-growing bamboo that is widely introduced in southern China and has great economic and ecological benefits. In recent years, a blight of B. pervariabilis × D. grandis caused by Arthrinium phaeospermum has led to much branch damage and even death of entire bamboo forests.MethodsTo screen for resistance genes in B. pervariabilis × D. grandis, transcriptome sequencing technology was used to compare the gene expression profiles of different varieties of B. pervariabilis × D. grandis with variable resistance and the same varieties under different treatments. The Clusters of Orthologous Groups of Proteins (COG) database; the Gene Ontology (GO) database; and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database were used to annotate and analyse the differentially expressed genes.ResultsA total of 26,157 and 11,648 differentially expressed genes were obtained in the different varieties after inoculation with A. phaeospermum and the same varieties after inoculation A. phaeospermum or sterile water, respectively. There were 23 co-upregulated DGEs and 143 co-downregulated DEGs in #3 and #8, #6 and #8, #6 and #3. There were 50 co-upregulated DGEs and 24 co-downregulated DEGs in the same varieties after inoculation A. phaeospermum or sterile water. The results showed that many genes involved in cell wall composition synthesis, redox reactions and signal transduction were significantly different after pathogen infection. Twenty-one candidate genes for blight resistance, such as pme53, cad5, pod, gdsl-ll and Myb4l, were found. The qRT-PCR results were consistent with the sequencing results, verifying their authenticity. These results provide a foundation for the further exploration of resistance genes and their functions.

Microscale heterogeneous pore occupancy with variable background resistance

Fluid flow through porous media often involves the spontaneous displacement of one immiscible fluid by another. On the level of adjacent channels, a pore doublet model can estimate the relative flow rates in the two channels and the final fluid occupancy of the pair. Pore doublet models nominally capture the dominant roles of capillarity and viscosity, by describing the flow using hydraulic circuit theory. However, this approach neglects the more complex fluid flow in the region where the immiscible fluids meet, and therefore the applicability of this model for low aspect-ratio pores commonly seen in natural media is questionable. We show that for large channel aspect ratios, the numerical results replicate the traditional pore doublet models; however, as the aspect ratio approaches unity, the accuracy of these models break down. We quantify the effect of complex flow on the final fluid occupancy, which we link to the excess energy dissipation rate from the flow near the immiscible interface. Our results indicate that a minimal 1D pore doublet model may be sufficient to model global dynamics, including the fraction of residual oil that remains trapped in a reservoir, where the pore diameter and length are comparable.

Evaluation of Training with Elastic Bands on Strength and Fatigue Indicators in Paralympic Powerlifting.

Background: Variable resistance training has recently become a component of strength and conditioning programs. Objective: This randomized counterbalanced cross-over study aimed to investigate the use of elastic bands (EB) and the traditional method (TRAD) and force indicators in a training session. Methods: 12 Paralympic athletes (age: 28.60 ± 7.60 years) participated in this three-week study. In the first week, the participants were familiarized with EB and TRAD and were tested for maximal repetition (1-RM). The research occurred in weeks 2 and 3, which included the pre-post training, during which the following measures were extracted: maximum isometric force (MIF), the peak torque (PT), rate of force development (RFD), fatigue index (FI), and time to MIF (Time). The athletes performed two tests, EB and TRAD, separated by a one-week interval. Results: Significant differences were found between the pre- and post-test for 1RM (p = 0.018, η2p = 0.412), MIF (p = 0.011, η2p = 0.415), PT (p = 0.012, η2p = 0.413), and RFD (p = 0.0002, η2p = 0.761). With the use of EB, there was a difference in RFD between TRAD before and EB after (p = 0.016, η2p = 0.761). There were significant differences in the before and after for FI between TRAD and EB (p < 0.001) and for Time (p < 0.001), indicating that training with the use of elastic bands promotes overload, characterized by increased fatigue and decreased strength. Conclusions: Training with EB did not decrease 1RM, PT, MIF or RFD, however, there was an increase in fatigue and time to reach MIF when compared to the method with fixed resistance.

Optimal determination of resistance coefficient of heating pipe network based on genetic algorithm

The variable resistance of pipe network is a key problem in the heating field. In order to get the variable resistance coefficient of pipe network more accurately in the heating process, this paper proposed an optimization identification method of variable resistance coefficient of heating pipe network based on genetic algorithm. Firstly, considering that the pressure data in the heating network is difficult to measure, this paper established a mathematical model for optimizing the identification of variable resistance coefficient at each end of the heating network under the condition of only flow observation data; Secondly, genetic algorithm was used to solve it. Finally, the model and algorithm were applied to practical engineering for verification. The relative error of identification results was less than 5%, and the algorithm had good stability and convergence. The results showed that this method could obtain the variable resistance coefficient of heating network with high accuracy when only the flow observation data was available, which could provide guidance for the operation adjustment of heating system.

Corynebacterium macginleyi in the era of MALDI-TOF MS: epidemiology, susceptibility patterns and prevalence of co-infection

Corynebacterium macginleyi has long been associated with ocular infections and has more recently been rarely implicated in systemic infections. There is a paucity of literature regarding the rate of C.macginleyi co-infection with other bacterial and viral pathogens and regarding the incidence of C.macginleyi infection in the paediatric population. In this study, we report 30 isolates of C.macginleyi of ocular origin from 26 patients, identified using matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS). The rates of co-isolation with bacterial and viral pathogens were 62% (n=16/26) and 39% (n=5/13), respectively, in this study. Of these, 13 patients had molecular testing performed as requested by treating clinicians for either the Chlamydia trachomatis/Neisseria gonorrhoeae PCR or herpes/enterovirus/adenovirus multiplex PCR. All isolates tested susceptible to linezolid, vancomycin and ciprofloxacin, with variable resistance to tetracycline, clindamycin and penicillin using EUCAST breakpoints.

Review and analysis of methods for applying vibration in ploughing

The vibration of the working bodies of the plows is forced and spontaneous. Forced vibration requires a drive from an energy source, and spontaneous vibration occurs without a drive if the working bodies are fixed to the frame by means of spring elements. In this case, the oscillation is caused by the variable soil resistance. The vibration mode should be such that the impulse and shock action of the working body allows the tool to be torn off from the treated medium, in which the soil relaxes and decomposes into components capable of mutual displacement. The effectiveness of vibration is to reduce the traction resistance of the plow. When choosing the direction of vibrations, preference should be given to transverse or vertical vibrations, since in the longitudinal direction of vibrations, the vibration speed should be greater than the speed of the plow. Such a mode of oscillation can be provided only with forced oscillations and, therefore, with additional energy consumption. Forced vibrations with a vertical direction may be less intense, but still effective. They can be realized by replacing the support wheel of the plow with a roller in the form of a regular octahedron with an inscribed circle diameter of 0.75 m. Since these vibrations do not coincide with the direction of movement of the plow, the speed of vibration may be less than the speed of movement of the plowing unit; anyway, a positive effect will be achieved.