Spiral Rod Research Articles

Effects of Varying Spiral-Ring Pitches on CO2 Absorption by Amine Solution in Concentric Circular Membrane Contactors.

The CO2 absorption flux while using monoethanolamide (MEA) solution in a spiral-wired channel was significantly enhanced by optimizing both the descending and ascending spiral ring pitch configurations within the filled channel. In this study, two distinct spiral ring pitch configurations were integrated into concentric circular membrane contactors to augment CO2 absorption flux. Spiral rods were strategically inserted to mitigate concentration polarization effects, thereby reducing mass transfer boundary layers and increasing turbulence intensity. A theoretical one-dimensional model was developed to predict absorption flux and concentration distributions across varying MEA absorbent flow rates, CO2 feed flow rates, and inlet CO2 concentrations in the gas feed. Theoretical predictions of absorption flux improvement were validated against experimental results, demonstrating favorable agreement for both ascending and descending spiral ring pitch operations. Interestingly, the results indicated that descending spiral ring pitch operations achieved higher turbulent intensity compared to ascending configurations, thereby alleviating concentration polarization resistance and enhancing CO2 absorption flux with reduced polarization effects. Specifically, under conditions of a 40% inlet CO2 concentration and 5 cm3/s MEA feed flow rate, a notable 83.69% enhancement in absorption flux was achieved compared to using an empty channel configuration. Moreover, a generalized expression for the Sherwood number was derived to predict the mass transfer coefficient for CO2 absorption in concentric circular membrane contactors, providing a practical tool for performance estimation. The economic feasibility of the spiral-wired module was also assessed by evaluating both absorption flux improvement and incremental power consumption. Overall, these findings underscore the effectiveness of optimizing spiral ring pitch configurations in enhancing CO2 absorption flux, offering insights into improving the efficiency and economic viability of CO2 capture technologies.

Numerical Investigation of Heat Exchanger Enhancement for a Staggered Arrangement with Corrugated Rods in Front

The heat exchanger is used in many industrial and engineering activities.Where, numerous applications confirms on a large heat transfer rate. However, the twisted tube is one of heat transfer rate enhancement methods. Also, the turbulent flows are often used instead of laminar for enhancement heat transfer rate. Therefore, the tube arrangement can be used in a suitable way for utilized this purpose. The shape features of tubes in the heat exchangers are very important for enhancing their performance. As well, the pressure drop and heat transfer rate have a remarkable effect on the thermal efficiency of the heat exchanger. In this research, a numerical investigation with a new way for heat exchanger tube staggered arrangement is presented. Where new solid spiral rods with oval sections are inserted in front of main tubes to induce high turbulent flow intensity as well as redistribution airflow over exchanger tubes. However, the new air distribution will help the airflow pressure over all the tubes to push the thermal boundary symmetrically behind the tubes. Therefore, two different sectional tubes were presented (circular and elliptical). These cross-sectional areas for both types have the same values. The main tubes have no twisted to prevent decreases in pressure. The numerical analysis used the K- ε model at a low Reynolds number to the simulation of this situation. Where, the eddy will generate in the vicinity region to pipe walls due to twisted pipe as well as the obstruction the cross flow. However, there are a good improvement of heat transfer rate without spend any energy depending on the control the shape and arrangement of pipes. The results show that the corrugated rod will increase the Nusselt number at different values of Reynolds. However, the elliptic tube gives the best results for heat transfer rate and maximum Nusselt number. The results compared with others works and give a good agreement.

Campylobacter Species: New Insight, Clinical Diagnosis and Laboratory Approach

Campylobacter, a prevalent cause of global gastroenteritis, has exhibited an escalating impact worldwide, affecting both industrialized and developing nations. Even though Campylobacter jejuni and C. coli are the main causes of infection, new pathogens make it imperative to comprehend the disease mechanisms, dynamics of transmission, and evolution of less-studied species. Accessible whole-genome sequences obtained through high-throughput sequencing have made it easier to conduct in-depth pathogenomic studies, particularly on species such as C. fetus and C. concisus. These studies have shown novel applications in clinical microbiology by revealing genomic traits associated with pathogenicity and offering insights into the evolutionary mechanisms shaping their genomes. Effective pathogen management urgently requires deeper understanding of the evolution of pathogenicity in emerging Campylobacter species are urgently required for effective pathogen management. This comprehensive review synthesizes existing knowledge and outlines future research directions in this crucial field. The Gram-negative, non-spore-forming, curved or spiral rods known as campylobacters include a "thermophilic group" that is important to the water industry and includes C. jejuni, C. coli, and C. upsaliensis. Acute diarrhea is the usual symptom of a human Campylobacter infection, and key virulence factors have been identified as antibiotic resistance genes and flagellar DNA. Many campylobacters are frequently found in sewage and treated sewage effluents, whereas surface waters are less contaminated. Testing for Campylobacter prevalence through epidemiological methods requires a careful balance between phenotypic and genotypic data. Campylobacters are sensitive to oxygen, but they have strong survival strategies that may involve the formation of biofilms. Methods of inactivation that work well for coliforms are thought to be appropriate for Campylobacter. In addition to providing a synthesis of current knowledge and identifying future research directions to advance strategies for the effective management and mitigation of Campylobacter-related infections, this thorough review highlights the urgent need for additional research to deepen our understanding of these pathogens. The investigation of genetic features linked to pathogenicity, dynamics of transmission, and survival strategies highlights the complex character of Campylobacter infections. The dynamic nature of Campylobacter as a primary cause of gastroenteritis necessitates continued research endeavors to guide focused interventions and lessen the worldwide impact of this grave public health issue.

Application of a new-type of defecator in the treatment of rectal fecal impaction

Objective: This study aimed to investigate the viability and safety of a novel defecator in managing rectal fecal impaction. Methods: In a descriptive case series, this new defecator was administered to constipated individuals among the ages of 18 and 80 years who met the diagnostic criteria for rectal fecal impaction and were identified with acute rectal fecal impaction through CT scans. The contraindications for this defecator included: (1) Anal stenosis, acute intestinal obstruction, and intestinal perforation; (2) Concomitant rectal malignant tumors; (3) Coagulation dysfunction, low platelet counts, gastrointestinal bleeding, or other bleeding risks; (4) Patients with severe underlying conditions affecting the heart, brain, lungs, or other systems; (5) Individuals with mental health disorders. Based on these criteria, clinical data from 42 patients with rectal fecal impaction who underwent treatment with the new defecator at Deyang People's Hospital between July 2020 and April 2023 were retrospectively analyzed.The defecator comprises three components: a head, a spiral rod, and a handle, constructed from disposable stainless steel wire. The treatment procedure involves the following steps: The patient assumes a flexed, supine position on their left side with their buttocks slightly protruding from the bed's edge. A transparent sealing bag is affixed to the buttocks, centered around the anus. With gloved hands inserted through the bag's entrance, a cotton ball soaked in liquid paraffin lubricates the anal canal and the head of the defecator's spiral rod. The defecator is then slowly rotated and inserted into the anus, with careful attention to any changes in resistance. Once the spiral rod is fully inserted, the patient is instructed to inhale and defecate while the defecator is slowly withdrawn, carrying the dislodged fecal matter, and depositing it into the sealed bag. This operation is repeated 2 to 3 times, followed by the injection of either 100 ml of 36°C normal saline or 60 ml of liquid paraffin into the rectum. After a 5 to 8-minute wait, the patient assumes a squatting position to expel any remaining feces from the rectum. The study assessed the operation time, single treatment success rate, pain levels during treatment, and the occurrence of complications. Results: All 42 patients successfully underwent treatment with the new defecator device, achieving a single treatment success rate of 100%. The average operation time was 11.0 minutes (range: 9.0 to 13.3 minutes). During treatment, 20 cases (47.6%) reported moderate to severe anal pain, with 1 case (2.4%) experiencing anal fissure bleeding, and 6 cases (14.3%) reporting discomfort such as palpitations and sweating. No serious complications, including rectal perforation, were observed in any case. Conclusion: The new defecator device demonstrates ease of use and safety, making it a feasible option for treating acute rectal fecal impaction.

Comparative study on flow and heat transfer characteristics of swirling impingement jet issuing from different nozzles

The flow and heat transfer characteristics of spiral rod (SR), twisted tape (TT), guide vane (GV) and thread grooves (TG) nozzles are compared by numerically and experimentally for swirl angle (θ) = 15°-60° and Reynolds number (Re) = 6000–12000. An experimental system is built to investigate the heat transfer characteristics of the impingement target. The experimental results show that the TG nozzle has the highest Nusselt number (Nu) in the stagnation region, 19.19%−55.98% higher than that of the other three nozzles for Re = 6000, and SR nozzle has the highest Nu except in the central area. In addition, it is shown that the gas chamber pressure of TG nozzle is much smaller than that of the other three nozzles. The numerical method studies the streamlines, turbulent kinetic energy and vortex distribution in the jet space, and the Nu under different θ and Re of the four types of nozzles, which is verified with the experimental results. The numerical results show that SR nozzle has the largest impingement velocity, the best heat transfer effect, and uniformity, and is obviously influenced by θ. With the increase of the impingement spacing of the four types of nozzles, the impingement area enlarges and cooling effect weakens simultaneously. By studying the flow and heat transfer characteristics, a new swirl nozzle design method based on heat transfer, heat uniformity and pressure loss is established.

Design of and Experiment with Secondary Cutting Equipment for Broccoli

To solve the problem of large-sized blocks in single-process broccoli cutting, this paper proposes the design of broccoli secondary cutting equipment, in which the screening device with differential round belts, spiral attitude-adjusting mechanism, double-baffle conveyor belt, block-centering chute and disc-type cutter are analyzed and designed. According to the simulation of the motion of the blocks on the differential belts, the speeds of the two belts were 300 mm/s and 600 mm/s, respectively. The kinematic analysis of the spiral attitude-adjusting mechanism was performed, and the speed of the spiral rod was calculated to be greater than 64.5 rpm. The speed of the double-baffle conveyor belt was greater than 10.61 rpm to not obstruct the blocks and achieve diversion. A force analysis of the inclined centering chute was performed to reduce the damage during block conveying, and the inclination angle of the inclined centering chute was calculated to be greater than 27.02°. The parameters of the blade and its driving motor were calculated. Effective secondary cutting equipment for broccoli was thus developed. After secondary cutting, the size difference of two small florets obtained was between 0–8 mm, the success rate of cutting was 94.8%, and the efficiency was 47 pieces/min, which verified the reasonableness and feasibility of the second cutting equipment scheme.

Evaluation of Discharging Surplus Soils for Relative Stirred Deep Mixing Methods by MPS-CAE Analysis

Most of the ground in Japan is soft, leading to great damage in the event of liquefaction. Various ground-improvement measures are being taken to suppress such damage. However, it is difficult to carry out ground-improvement work while checking the internal conditions of the ground during the construction. Therefore, a visible and measurable evaluation of the performance of the ground-improvement work was conducted in this study. The authors performed a simulation analysis of the relative stirred deep mixing method (RS-DMM), a kind of ground-improvement method, using a computer-aided engineering (CAE) analysis based on particle-based methods (PBMs). In the RS-DMM, the “displacement reduction type (DRT)” suppresses displacement during construction. Both the DRT and the normal type (NT) were simulated, and a visible and measurable evaluation was performed on the internal conditions during each construction, the quality of the improved body, and the displacement reduction performance. As an example of these results, it was possible to visually evaluate the discharge of surplus soil by the spiral rod attached to the stirring wing of the DRT. In addition, the authors succeeded in quantitatively showing that more surplus soil was discharged when the stirring wing of the DRT was used than when the stirring wing of the NT was used.

Helicobacter cinaedi bacteraemia secondary to enterocolitis in an immunocompetent patient

BackgroundHelicobacter cinaedi are motile, gram-negative spiral rods with a natural reservoir in the intestinal tract of hamsters and rhesus monkeys. In humans, H. cinaedi has been reported in different human infections like fever, abdominal pain, gastroenteritis, proctitis, diarrhoea, erysipelas, cellulitis, arthritis, and neonatal meningitis typically diagnosed by positive blood cultures. Even though H. cinaedi has been detected from human blood and stool the entry of H. cinaedi into the blood stream was undocumented until quite recently. The use of pulse-field gel electrophoresis (PFGE) demonstrated that stool- and blood-derived H. cinaedi strains were consistent.Case presentationHere, we describe a rare Danish case of H. cinaedi bacteraemia in an immunocompetent 44-year-old male with diarrhoea. We isolated H. cinaedi from a blood culture taken at admission, and from a FecalSwab taken at day six despite ongoing antibiotic therapy. Next, we made a genetic comparison of both isolates by use of Multi-locus sequence typing (MLST)- and Single nucleotide polymorphism (SNP)-analysis. The two isolates were identical with zero SNPs and by use of MLST the isolate was identified as a novel ST20, confirming previous data of the intestinal tract as a route of H. cinaedi bacteraemia. The results of our AST showed a resistance pattern with higher MICs for ciprofloxacin and clarithromycin than for ampicillin, amoxicillin, gentamicin, and imipenem. The patient was cured with targeted therapy with pivampicillin; however, the primary source of transmission was unknown.ConclusionsIn conclusion, this case of H. cinaedi bacteraemia secondary to enterocolitis in an immunocompetent patient provide clear evidence that one route of infection occurs through translocation from the intestinal tract to the bloodstream. Helicobacter cinaedi from blood and faeces were identical with a novel ST20, resistant to ciprofloxacin and clarithromycin however, the patient was cured with oral pivampicillin.

An Optimized Design Research Based on Variable-lead Spiral Pair of Contact Stress and Elasto-hydrodynamic Lubrication State

Abstract: Variable-lead spiral pair mainly includes spiral wire and spiral roller. Design of variable-lead helix firstly conforms to the motion characteristics of variable-lead screw drive and nut-connected mechanism, then comes to lead function of the variable lead helix. At the same time, according to the range of screw lead angle and pressure angle, the angular velocity of spiral wire rod and the radius of spiral wire are concluded. Finally come to the parameter equation of helix. Then, the contact analysis and lubrication characteristics of the variable-lead helical pair are analyzed to design the helical roller with the minimum contact stress and the condition of the elasto-hydrodynamic lubrication. The radius of the variable-lead helical roller and the selectable range of the bus length are obtained. Finally, an example is given to illustrate the application of the variable-lead spiral pair in the subway door system, and the optimization design of the variable-lead spiral pair is realized.

Solution for free vibration of spatial curved beams

PurposeThe purpose of this paper is to propose and analyze the free vibration response of the spatial curved beams with variable curvature, torsion and cross section, in which all the effects of rotary inertia, shear and axial deformations can be considered.Design/methodology/approachThe governing equations for free vibration response of the spatial curved beams are derived in matrix formats, considering the variable curvature, torsion and cross section. Frobenius’ scheme and the dynamic stiffness method are applied to solve these equations. A computer program is coded in Mathematica according to the proposed method.FindingsTo assess the validity of the proposed solution, a convergence study is carried out on a cylindrical helical spring with a variable circular cross section, and a comparison is made with the finite element method (FEM) results in ABAQUS. Further, the present model is used for reciprocal spiral rods with variable circular cross section in different boundary conditions, and the comparison with FEM results shows that only a limited number of terms in the results provide a relatively accurate solution.Originality/valueThe numerical results show that only a limited number of terms are needed in series solutions and in the Taylor expansion series to ensure an accurate solution. In addition, with a simple modification, the present formulation is easy to extend to analyze a more complicated model by combining with finite element solutions or analyze the transient responses and stochastic responses of spatial curved beams by Laplace transformation or Fourier transformation.

Arcobacter butzleri strains isolated from different sources display adhesive capacity to epithelial cells in vitro

Background: The genus Arcobacter, belonging to the family Campylobacteraceae, includes polar flagellated, curved or spiral rod shaped bacteria firstly described as Vibrio/Spirillum organisms and later as aerotolerant Campylobacter-like microorganisms. Currently, this genus comprises nine validated species and a candidatus. Among Arcobacter species, Arcobacter butzleri is recognized as a zoonotic agent and the most common species of the genus isolated from environmental water, food and clinical samples. Recently, this species was considered a serious hazard to human health. However, their pathological properties, potential virulence factors as well as their clinical significance remain uncertain or not completely defined. The aim of this study was to establish the ability of 78 A. butzleri strains isolated from different sources to adhere to HEp-2 cells in vitro. Materials, Methods & Results: All the strains were isolated using first an enrichment medium incubated aerobically at 26oC for 48h. After that, 100 µL of the broth were streaked onto Arcobacter selective agar plates and incubated at 26°C for 72h. All the strains were identified phenotypically using standard assays. Definitive identification was achieved using a multiplex polymerase chain reaction. Adhesive capacity was determined infecting HEp-2 cells with the strains under study following Skaletsky et al. protocol, with slight modifications. An adherent Escherichia coli isolate was included as a positive control, whereas uninoculated cell lines were used as negative controls. Adhesion results were expressed as the percentage of HEp-2 cells showing adhering bacteria and the number of bacteria (± SD) adhered to cells was determined. Strains were considered as adherent, if at least 20% of HEp-2 cells showed one ore more adhered bacteria. Adherence was also demonstrated by scanning electronic microscopy. All the strains showed adhesive capacity to HEp-2 cells in vitro. The lowest adhesion percentage (27%) was observed in a strain isolated from dog feces. In at least one strain per source it was possible to observe 100% adhesion. The lowest number of adhered bacteria (1.03 ± 1.53) was observed in a strain isolated from river water and the highest number (76.6 ± 5.59), in a strain isolated from duck feces. Discussion: Regardless of their isolation source, the 78 Arcobacter butzleri strains tested in the present study were able to adhere to HEp-2 cells in vitro. This property was demonstrated in different proportions by other authors in strains isolated from environmental, meat and human fecal samples. Electronic scanning microscopy shows curved bacilli adhering to HEp-2 cells forming a microcolony-like arrangement. This may occur in a stepwise mechanism. First, A. butzleri adhere to HEp-2 cells and then, due to their capacity to form biofilms, interbacterial adherence can be expressed. The capacity of A. butzleri to form biofilms attaching to stainless steel, copper and glass has been demonstrated in previous studies. Further studies are necessary to elucidate the molecular and cellular mechanisms accounting for this biological property; and hence, its actual role in the colonization of human and animal intestinal epithelium by A. butzleri.

Desulfovibrio desulfuricans bacteremia: A case report and literature review

Desulfovibrio spp. are sulfate-reducing, anaerobic bacteria that are ubiquitously found in the environment. These organisms infrequently cause human infections, and the clinical characteristics of infection with Desulfovibrio spp. remain unclear. Here, we describe a case of Desulfovibrio desulfuricans bacteremia in an 88-year-old Japanese man with a past medical history of thoracic endovascular aortic repair (TEVAR). His chief complaint was hemoptysis for 2 weeks. A chest contrast-enhanced computed tomography demonstrated an enlarged thoracic aortic aneurysm surrounded by a ring-enhanced lesion, recognized as mediastinal abscess. Gram-negative spiral bacilli were detected in anaerobic blood culture. These bacteria could not be identified using conventional methods, but by analyzing a full base sequence of 16S rDNA, they were identified as D. desulfuricans subsp. desulfuricans. The patient underwent an emergent re-TEVAR, and the infection subsided after being treated with tazobactam/piperacillin and clindamycin, followed by metronidazole. A literature review of previous cases of D. desulfuricans bacteremia suggested that the pathogen was derived from bacterial translocation from the intestine in most cases. Desulfovibrio infection is presumably underestimated due to its infrequency, indolent growth, and difficulty in identification. Desulfovibrio spp. should be suspected when spiral rods are observed in anaerobic culture, and molecular analysis is required for accurate species-level differentiation of the pathogens. To better understand the pathogenicity of these fastidious organisms, further cases based on the exact bacterial identification should be investigated.

Effects of indigo carmine concentration on the morphology and microwave absorbing behavior of PPy prepared by template synthesis

In the study, a series of polypyrrole (PPy) samples were prepared by a method of template synthesis at different indigo carmine (IC) concentrations while keeping the amount of pyrrole and FeCl3 as well as the reaction conditions unchanged. Effects of IC concentration (MIC) on the morphology, conductivity and microwave absorbing behavior of the obtained PPy products were investigated. The results showed that the morphology of PPy transformed from granular flocking to rods and then to spiral rods as MIC increased from 0.05 to 7.50 mM, and the morphology transformation mechanism of PPy was attributed to the structural transformation of IC micelles caused by the change of MIC. The conductivity of PPy was also found to be influenced by MIC. Further investigation indicated that the spiral rod-shaped PPy (S-5) showed obviously superior microwave absorbing behavior compared with that of the granular flocking shaped PPy or that of the rod-shaped PPy, which was attributed to the benefits of its spiral structure and the comparably higher dielectric loss resulted from its lower conductivity.

Campylobacter jejuni ssp. jejuni bacteraemia in a patient with BCR-ABL-positive chronic myelogenous leukaemia in remission on dasatinib therapy

Introduction: We report an unusual case of Campylobacter jejuni bacteraemia in a patient with Philadelphia chromosome-positive, BCR-ABL-positive chronic myelogenous leukaemia in complete cytogenetic and major molecular remission after dasatinib/IFN therapy. Case presentation: On admission, the patient presented with fever and acute haemorrhagic diarrhoea. Initial empiric antibiotics consisted of ceftriaxone and metronidazole. Stool and blood culture samples were collected and submitted for evaluation; these specimens were processed as per laboratory protocol. Several Gram-negative, spiral rods could be identified microscopically in Gram-stained slides from bottled blood and stool cultures. Isolate identification was performed on the Vitek 2 system using a GN identification card and API Campy strips and by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Discrepant identification was obtained between the Vitek versus the API Campy test and MALDI-TOF. Erythromycin susceptibility testing was done using an Etest, whereas all other susceptibility testing and breakpoint analysis was done following the EUCAST procedure. Initial empiric antibiotic treatment was switched from ceftriaxone to ciprofloxacin according to antibiotic susceptibility testing (AST) and Etest (ciprofloxacin MIC of 0.094 μg ml− 1) results. C. jejuni bacteraemia was successfully eradicated after 1 week of ciprofloxacin therapy. Conclusion: This case describes the rare event of a Campylobacter bacteraemia, which could have been falsely interpreted because of non-specific colony morphology and the initial Vitek result. Only the combination of microscopy, MALDI-TOF and an API Campy test was able to rapidly identify this bacterium as C. jejuni. This case also shows the importance of immediate AST- and MIC-adapted antibiotic treatment in immunocompromised febrile patients suffering from Campylobacter-induced bloody diarrhoea.

Control of morphology and electromagnetic properties of polypyrrole synthesized by the template method

This article presents a contribution to a better understanding of the effects of pH value on the morphology, conductivity, and reflection loss of polypyrrole (PPy) prepared at different pH values using indigo carmine (IC) as the synthesis template. The results indicate that the morphology of PPy changes from spiral rods to nonspiral rods, then to particles, which is attributed to the gradual morphological change of IC micelle templates from prismatic structure to rugby-like structure, and finally to spherical structure. Further study demonstrates that the conductivity of PPy decreases with the gradual decrease of the pH value, as a result of gradually increased contact resistance and the degree of electron delocalization. With the decrease of the pH value, the maximum reflection loss of PPy gradually increases and the corresponding loss peak moves to higher frequency points simultaneously.

Non-selective regulation of peroxide and superoxide resistance genes by PerR in Campylobacter jejuni.

Campylobacter jejuni is an important foodborne pathogen. The molecular mechanisms for the regulation of oxidative stress resistance have not yet been understood fully in this bacterium. In this study, we investigated how PerR (peroxide stress regulator) modulates the transcriptional regulation of both peroxide and superoxide resistance genes in C. jejuni, particularly under oxidative stress conditions. The transcriptional levels of ahpC, katA, and sodB were substantially increased by aeration and oxidant exposure. Interestingly, a perR mutation completely abrogated the transcriptional response of ahpC, katA and sodB to oxidants. Furthermore, we demonstrated that perR transcription was reduced by aeration and oxidant exposure. In contrast to the unique role of PerR homologs in peroxide stress regulation in other bacteria, C. jejuni PerR directly regulates the transcription of sodB, the most important gene in superoxide defense, as evidenced by the alteration of sodB transcription by the perR mutation and direct binding of rPerR to the sodB promoter. In addition, we also observed notable morphological changes in C. jejuni from spiral rods to cocoid morphology under aerobic conditions. Based on the intracellular ATP levels, C. jejuni entered a viable-but-non-culturable (VBNC) state under aerobic conditions. These findings clearly demonstrate that C. jejuni possesses a unique regulatory mechanism of oxidative stress defense that does not specifically distinguish between peroxide and superoxide defense, and PerR plays a pivotal role in this non-selective regulation of oxidative stress resistance in C. jejuni.

Reactions of chicken sera to recombinant Campylobacter jejuni flagellar proteins.

Campylobacter jejuni is a Gram-negative spiral rod bacterium and is the leading but underreported bacterial food-borne pathogen that causes human campylobacteriosis worldwide. Raw or undercooked poultry products are regarded as a major source for human infection. C. jejuni flagella have been implicated in colonization and adhesion to the mucosal surface of chicken gastrointestinal tracts. Therefore, flagellar proteins would be the excellent targets for further investigation. In this report, we used the recombinant technology to generate a battery of C. jejuni flagellar proteins, which were purified by His tag affinity chromatography and determined antigenic profiles of these recombinant flagellar proteins using sera from chickens older than 6 weeks of age. The immunoblot results demonstrate that each chicken serum reacted to various numbers of recombinant flagellar proteins. Among these recombinant proteins, chicken sera reacted predominantly to the FlgE1, FlgK, FlhF, FliG and FliY proteins. These antibody screening results provide a rationale for further evaluation of these recombinant flagellar proteins as potential vaccines for chickens to improve food safety as well as investigation of host immune response to C. jejuni.

Exact solution for free vibration of curved beams with variable curvature and torsion

For the purpose of investigating the free vibration response of the spatial curved beams, the governing equations are derived in matrix formats, considering the variable curvature and torsion. The theory includes all the effects of rotary inertia, shear and axial deformations. Frobenius' scheme and the dynamic stiffness method are then applied to solve these equations. A computer program is coded in Mathematica according to the proposed method. As a special case, the dynamic stiffness and further the natural frequencies of a cylindrical helical spring under fixed-fixed boundary condition are carried out. Comparison of the present results with the FEM results using body elements in I-DEAS shows good accuracy in computation and validity of the model. Further, the present model is used for reciprocal spiral rods with different boundary conditions, and the comparison with FEM results shows that only a limited number of terms in the resultant provide a relatively accurate solution.

Development of Air Hammer with Self-Propelled Round Bit and the Contact Analysis of the Key Components

Within the vertical section, ROP of the conventional air hammer in gas drilling is several times or even several dozen times than that of underbalanced drilling. Gas screw with conventional air hammer has not been successful in direction gas well, which greatly limits field of application of air hammer, so this paper carries out development of the air hammer with self-propelled round and analyzes the principle of work of air hammer with self-propelled round bit, the contact analysis and design of spiral rod, and spiral nut which are the key components.

Endoscopic and histologic appearance of rectal syphilis

View Large Image Figure Viewer Download Hi-res image A 28-year-old man with HIV (348 CD4+ T cells/mm3 [normal 600-1500 cells/μL]) who was not on antiretroviral therapy was referred for evaluation of constant rectal pain radiating to the right upper quadrant of the abdomen. The pain had persisted for 3 weeks and was exacerbated by both bowel movements and sitting upright. He noted scant hematochezia and normal, formed stools. A rapid plasma reagent (RPR, 1:32) and specific treponemal test (FTA-abs) were reactive. Endoscopic evaluation of the rectum revealed severe ulcerative proctitis with marked mucosal friability, extending 5 cm proximal from the anal canal (A). Histologic examination of rectal biopsy specimens revealed chronic active colitis with cryptitis and ulceration (B, Steiner silver stain, orig. mag. ×400), and multiple spiral rods, consistent with spirochetes, present throughout the inflamed mucosa. The patient was treated with 3 doses of intramuscular penicillin G benzathine 2.4 million units and had rapid resolution of symptoms.