Filamentous Rods Research Articles

Identification of Snowdrop Virus Y Occurred on Narcissus spp. in Korea

Metatranscriptome analysis and reverse transcription polymerase chain reaction diagnostics were conducted to investigate viral disease in 75 Narcissus samples, resulting in the detection of snowdrop virus Y (SVY). The complete genome sequence of the SVY isolate SA66 was 10,560 nt in length, and sequence analysis revealed a typical genome structure for Potyvirus. Electron microscopy revealed filamentous rod particles approximately 800 nm long in the infected samples. In the bioassay involving 19 test plants, no SVY infection was confirmed. The coat protein sequences of 10 SVY isolates from various samples were determined, showing nucleotide identities of 99.3-99.8% and amino acid identities of 98.9-99.6% when compared with three previously reported isolates. The complete genome sequence shared 99.6% nucleotide identity and 99.7% amino acid identity with the reported isolate. SVY was detected in 10 of the collected samples, specifically showing partial detection in all four cultivars from the Sinan region, while it was not detected in the other three regions. This study is the first report of SVY in Korea and is expected to contribute to the quarantine of Narcissus bulbs and to the production of virus-free bulbs.

Serological and morpho-molecular characterization of papaya ringspot virus (PRSV) infecting the papaya (Carica papaya) in Tamil Nadu

Papaya ringspot virus (PRSV) is wreaking havoc on papaya cultivation, leading to significant crop losses. Present study was carried out during 2022 and 2023 at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu aimed to identify and characterize PRSV in four districts of Tamil Nadu. The incidence of the PRSV ranged from 32–100% in the surveyed districts. Samples displaying symptoms such as mosaic patterns, mottling, yellowing, puckering, shoestring appearance, oily stains on stems and petioles, deformed fruits, and concentric rings on fruits were collected for PRSV confirmation. The preliminary diagnosis of samples using DAS-ELISA showed the presence of PRSV in leaf and fruit skin samples but the absence of the virus in flower and seed samples. The existence of flexuous, filamentous rod- shaped particles measuring 809 nm × 15 nm in the tested leaf sample showed the incidence of Potyvirus, as revealed by transmission electron microscopy (TEM). Molecular characterization of PRSV in leaf and fruit skin samples was carried out using PCR with PRSV coat protein-specific primers, resulting in the amplification of an 850 bp product. Sequencing of the amplified products showed that the partial sequences of isolates CBE1-TN and ANR1-TN were 99.99% identical. Early detection of PRSV is imperative for implementing effective management strategies.

Proteomic Analysis of Crimped and Straight Wool in Chinese Tan Sheep.

Crimped wool in Tan sheep gradually transitions to straight wool after 35 days (the er-mao stage), which reduces its commercial value. To investigate the changes in wool proteins during this stage, we performed comparative proteomic analysis of the straight and crimped wool using tandem mass tag (TMT)-based quantification. The mean fur curvature (MFC) of crimped wool was significantly greater than that of straight wool (p < 0.001). We identified 1218 proteins between the two types of wool, including 50 keratins (Ks) and 10 keratin-associated proteins (KAPs). There were 213 differentially expressed proteins, including 13 Ks and 4 KAPs. Crimped wool showed relatively high abundances of KAP24-1, K84, K32, K82, and intermediate filament rod domain-containing protein (IRDC), whereas straight wool had relatively high abundances of K6A, K27, K80, KAP16-1, KAP27-1, and trichohyalin (TCHH). The expression levels of KAP16-1, KAP24-1, and KAP27-1 were related to the ratio of paracortex, which may be associated with wool crimp formation. Additionally, high expressions of TCHH, K27, and K6A in the inner root sheath (IRS) were linked to fiber fineness in straight wool. These findings provide insight into the overall expression and distribution patterns of Ks and KAPs, offering opportunities to improve wool quality and enhance its economic potential in the textile industry.

Erythrasma of the Vulva: An Invisible Dermatosis.

Erythrasma is a prevalent superficial bacterial infection typically caused by Corynebacteria species and preferentially affecting intertriginous sites including axillary, interdigital, and inguinal skin folds. However, erythrasma of the vulva is uncommon, with only 2 cases previously reported. Although erythrasma can be diagnosed clinically using Woods lamp examination, it may not always be considered in the differential diagnosis for patients presenting with persistent vulvar pruritus. We report 12 cases of vulvar erythrasma identified by histopathology, with a review of clinical and histologic features. The mean patient age was 60.1yr and the mean patient BMI was 30.5. Five of 12 patients presented with pruritic rash. The time from symptom onset to diagnosis was 9mo in 1 case, >18mo in 4 cases, and unknown in the remaining cases. The characteristic histologic features were compact orthokeratosis and mild perivascular chronic inflammation. In all 12 cases, Periodic Acid-Schiff-diastase (PAS-D) staining highlighted intracorneal filamentous rods which were not readily appreciable on H&E. After the diagnosis of erythrasma, 4 patients were treated with topical lincomycin, of whom 3 had clinical improvement in symptoms. One patient was treated with topical macrolide antibiotic and also reported improvement in symptoms. Consideration of erythrasma on the differential for patients presenting with vulvar rash and pruritus may shorten the time to diagnosis and treatment, minimize patient discomfort, and reduce the scope and cost of diagnostic testing.

Comparative drawability and recrystallization evaluation of Nb4Ta and Nb4Ta1Hf alloys, and the beneficial influence of Hf on developing finer Nb3Sn grain size

Comparative drawability and recrystallization evaluation of Nb4Ta and Nb4Ta1Hf alloys, and the beneficial influence of Hf on developing finer Nb3Sn grain size

Elastic response of colloidal smectic liquid crystals: Insights from microscopic theory.

Elongated colloidal rods at sufficient packing conditions are known to form stable lamellar or smectic phases. Using a simplified volume-exclusion model, we propose a generic equationof state for hard-rod smectics that is robust against simulation results and is independent of the rod aspect ratio. We then extend our theory by exploring the elastic properties of a hard-rod smectic, including the layer compressibility (B) and bending modulus (K_{1}). By introducing weak backbone flexibility we are able to compare our predictions with experimental results on smectics of filamentous virus rods (fd) and find quantitative agreement between the smectic layer spacing, the out-of-plane fluctuation strength, as well as the smectic penetration length λ=sqrt[K_{1}/B]. We demonstrate that the layer bending modulus is dominated by director splay and depends sensitively on lamellar out-of-plane fluctuations that we account for on the single-rod level. We find that the ratio between the smectic penetration length and the lamellar spacing is about two orders of magnitude smaller than typical values reported for thermotropic smectics. We attribute this to the fact that colloidal smectics are considerably softer in terms of layer compression than their thermotropic counterparts while the cost of layer bending is of comparable magnitude.

A Neglected Swollen Limb: Resurgence or Common Tropical Disease?

Mycetoma is uncommon, chronic granulomatous infection caused either by fungi or by aerobic filamentous actinomycetes which is characterized by a triad of painless subcutaneous mass, multiple sinuses and discharge containing grains. We report a case of 40 years old male, farmer who presented with multiple painless swollen lesions over right foot for 8 years. Swelling had gradually increased in size over a few years followed by multiple episodes of discharge. It had not restricted his daily activities. On examination, there were multiple nodules and sinuses discharging serous fluid from the right foot. Gram staining showed gram positive filamentous rods and KOH was negative. Histopathology showed multiple granulomas. Patient was treated for 5 cycles using modified Welsh regimen with Amikacin 750mg intravenously once a day, oral Cotrimoxazole 960mg twice daily and oral Rifampicin 600mg once daily along with oral iron and folic acid supplementation continuously for 21days which constituted 1 cycle with an interval of 15 days between each cycle. Patient was assessed by measuring girth of foot and number of lesions in each visit and showed significant improvement at the end of fifth cycle. Patient was followed for 1 year after treatment without any recurrence.

Vertebral osteomyelitis caused by Fusobacterium nucleatum with an associated asymptomatic liver abscess in an immunocompetent adult: A case report and literature review

Fusobacterium nucleatum rarely causes vertebral osteomyelitis or liver abscesses, and no reports exist of it concurrently causing vertebral osteomyelitis and pyogenic liver abscess. A 58-year-old woman with a history of periodontitis presented with worsening lumbago, left lower leg pain, numbness, and fever for a week. Physical examination indicated knocking pain at the L2-L3 levels with a psoas sign on the left side. A magnetic resonance image showed L2-S1 vertebral osteomyelitis and intervertebral discitis, with a left psoas major muscle abscess. Vertebral osteomyelitis caused by Staphylococcus aureus was suspected; blood cultures were obtained, and intravenous cefazolin was administered. Computed tomography, which was performed to detect disseminated foci, revealed a multilocular liver abscess. On day 4 of incubation, the anaerobic blood culture bottles were positive for characteristic filamentous gram-negative rods. The empiric antimicrobial therapy was changed to ampicillin/sulbactam. The isolate was identified as F. nucleatum based on 16S rRNA gene sequencing. The liver abscess was drained on day 12. Based on the antimicrobial susceptibility test results, the patient was treated with intravenous ampicillin/sulbactam for 4 weeks followed by oral amoxicillin/clavulanate for an additional 8 weeks and remained disease-free at the 1-year follow-up. Clinicians should consider F. nucleatum as the causative organism for vertebral osteomyelitis presenting with asymptomatic pyogenic liver abscess. The gold standard for identifying and diagnosing F. nucleatum infections is 16S rRNA gene sequencing, and gram staining helps determine appropriate antimicrobials.

Corynebacterium ulcerans as filamentous branching rods

A 33-year-old man presented at the hospital because of a left axillary adenitis which appeared one month before. He had no prior medical history and was up-to-date on his vaccinations. He had two dogs and had been in recent contact with cattle in the course of his work as a rat exterminator. Physical examination revealed a growing and inflammatory axillary lesion associated with a dry cough. Blood analysis revealed hypereosinophilia (eosinophils count: 2.53x109/L). The Gram staining of the lymph node aspiration showed Gram-variable filamentous branching rods (Fig.

Case report and successful management of canine aortic endocarditis caused by Actinomyces neuii subsp. anitratus (Winkia neuii subsp. anitrata)

BackgroundCanine aortic valve endocarditis carries a poor prognosis. In the current literature there are only two reports of infectious endocarditis associated with Actinomyces; Actinomyces turicensis and an Actinomyces-like organism. Endocarditis due to Actinomyces neuii subsp. anitratus (now known as Winkia neuii subsp. anitrata) has rarely been reported in humans, and to the best of our knowledge, has never been reported in dogs.Case presentationA 4 year-3 months old female neutered Great Dane presented with lethargy, hyporexia, ‘praying position’ stance, acute onset of cherry eye and pyrexia. A subtle diastolic heart murmur was detected on thoracic auscultation and echocardiology revealed an irregular lesion adhered to the ventricular aspect of the aortic valve, suggestive of aortic valve endocarditis. Peripheral blood was collected for blood culture. Following 10 days of incubation, blood cultures yielded a growth of aerobic gram-positive filamentous rods which were further biochemically (BioMerieux API Coryne profiling strip) identified as Actinomyces neuii subsp. anitratus. The patient was treated with marbofloxacin and amoxicillin/clavulanic acid for five consecutive months. On repeat echogram, following treatment completion, there was no evidence of aortic valve endocarditis. To the best of our knowledge this is the first case report documenting successful treatment of aortic valve endocarditis caused by Actinomyces neuii subsp. anitratus in a dog.ConclusionsDespite the poor prognosis of canine infectious aortic valve endocarditis, patients with Actinomyces neuii subsp. anitratus infection might have a favourable outcome. It is therefore important identifying the underling infectious cause, as it may have a significant impact on prognosis and treatment outcome when it is caused by Actinomyces neuii subsp. anitratus.

COMPLICATIONS OF HIGH-DOSE STEROIDS IN COVID-19

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: The novel coronavirus disease (COVID-19) has been associated with diffuse lung injury. Corticosteroids have been shown to suppress inflammation-mediated lung injury and as a result, decrease progression to respiratory failure. Based on the RECOVERY trial, the use of dexamethasone in patients hospitalized with COVID-19 resulted in lower 28-day mortality among those who were receiving either invasive mechanical ventilation or supplemental oxygen at randomization [1]. Per IDSA treatment guidelines dexamethasone use in hospitalized patients is strongly recommended, thereby prompting most intuitions in the United States and worldwide to initiate its use. We present a unique case of Nocardia farcinica brain abscess in the setting of prolonged dexamethasone use in a patient with COVID-19 infection. CASE PRESENTATION: 80-year-old female from Pakistan with a past medical history of hypertension, who while in Pakistan was diagnosed with COVID-19 and treated with Xarelto and dexamethasone (dose and duration unknown). Her course was complicated by the development of left elbow and hand Zoster and over the 10 days prior to presentation, she was noted to develop increasing left-sided weakness and aphasia. Patient was transferred to the United States where a CT scan revealed a left frontal mass, prompting transfer to a tertiary care facility. MRI brain revealed a left frontal cystic rim-enhancing lesion that was concerning for a brain abscess. The patient subsequently underwent left frontal stereotactic brain biopsy with recovery of 3 mL of purulent fluid. Gram staining revealed beaded branching gram-positive rods. She was initially placed on vancomycin/cefepime/metronidazole/dexamethasone and was changed to IV Bactrim/ceftriaxone/doxycycline to cover for Nocardia and Actinomyces. Modified acid-fast stain returned positive with beaded, branching, filamentous rods, consistent with Nocardia. Cultures returned with Nocardia farcinica. DISCUSSION: Nocardia infection primarily occurs via inhalation or direct skin inoculation and subsequently disseminates hematogenously to end organs, which include the brain [2]. Nocardia typically presents as a respiratory or skin infection;brain abscesses are rare and primarily found in immunocompromised patients. As outlined in this case, an immunocompromised state was induced by high dose steroid use. Corticosteroids modulate inflammatory mediators and thereby cause immunosuppression. New symptoms should be monitored closely in patients undergoing steroid therapy, as seen in our patient who presented with new onset aphasia and left sided weakness. This is especially true during the COVID-19 pandemic that has prompted widespread use of dexamethasone in order to prevent respiratory failure and death. CONCLUSIONS: Physicians should be vigilant of superimposed infections in patients with COVID-19 receiving high dose steroids. REFERENCE #1: RECOVERY Collaborative Group. Dexamethasone in Hospitalized Patients with Covid-19. N Engl J Med. 2021;384(8):693-704. doi:10.1056/NEJMoa2021436. REFERENCE #2: Lin YJ, Yang KY, Ho JT, Lee TC, Wang HC, Su FW. Nocardial brain abscess. J Clin Neurosci. 2010;17(2):250-253. doi:10.1016/j.jocn.2009.01.032 DISCLOSURES: No relevant relationships by Waqas Bhatti, source=Web Response No relevant relationships by Tanisha Kaur, source=Web Response

Upcycling Postconsumer High-Density Polyethylene (PC-HDPE): Thermal Stability and Kinetics Study of the Filaments Extruded from PC-HDPE

Thermal stability and kinetics of thermolysis of postconsumer milk containers made of high-density polyethylene (PC-HDPE) and filament rods extruded from them (HDPE-F) were examined by thermogravimetric analysis (TGA) with six linear temperature programs under a stream of nitrogen. The total weightloss of each sample took place in a one-step decomposition to volatiles at the heating rates, β = 1, 10, 25, 50, 70, and 100 Kmin-1. The values of initial decomposition temperature, the temperature at the maximum thermal degradation rate, and the maximum rate of decomposition were increased by increasing the heating rate as was the expectation. The isoconversional method was used to evaluate the fundamental kinetic parameters, the activation energy barrier (Ea ), the Arrhenius pre-exponential factor (A), and the mechanism of the reaction, f(α). The values of Ea were independent of the model and heating rate, as was expected. However, the values of A depended on the model and the extent of reaction (α). The values of the Ea of PC-HDPE initiated at 171 kJ/mol at α = 0.05 and it increased to 207 kJ/mole at α = 0.95. The values of Ea of the HDPE-F rod were relatively constant for all α values, being 227 ± 3 kJ/mol. It was justified by the absence of easily volatilized substances in the HDPE-F. Knowledge of the thermal stability and decomposition kinetics of the starting materials (PC-HDPE) and the product (HDPE-F) is important in the context of thermochemical conversion processes aimed at the use of PC-HDPE as raw materials for recycling, upcycling, and down-cycling for objects used under room conditions.

Novel hyperthermophilic crenarchaeon Infirmifilum lucidum gen. nov. sp. nov., reclassification of Thermofilum uzonense as Infirmifilum uzonense comb. nov. and assignment of the family Thermofilaceae to the order Thermofilales ord. nov.

A novel hyperthermophilic crenarchaeon, strain 3507LTT, was isolated from a terrestrial hot spring near Tinguiririca volcano, Chile. Cells were non-motile thin, slightly curved filamentous rods. It grew at 73-93°C and pH range of 5 to 7.5 with an optimum at 85°C and pH 6.0-6.7. The presence of culture broth filtrate of another hyperthemophilic archaeon as well as yeast extract was obligatory for growth of the novel isolate. Strain 3507LTT is an anaerobic chemoorganoheterotroph, fermenting monosaccharides, disaccharides and polysaccharides (lichenan, starch, xanthan gum, xyloglucan, alpha-cellulose and amorphous cellulose). No growth stimulation was detected when nitrate, thiosulfate, selenate or elemental sulfur were added as the electron acceptors. The complete genome of strain 3507LTT consisted of a single circular chromosome with size of 1.63 Mbp. The DNA G+C content was 53.9%. According to the 16S rRNA gene sequence as well as conserved protein sequences phylogenetic analyses, strain 3507LTT together with Thermofilum uzonense formed a separate cluster within a Thermofilaceae family (Thermoproteales/Thermoprotei/Crenarchaeota). Based on phenotypic characteristics, phylogeny as well as AAI comparisons, a novel genus and species Infirmifilum lucidum strain 3507LTT (=VKM B-3376T=KCTC 15797T) gen. nov. sp. nov. was proposed. Its closest relative, Thermofilum uzonense strain 1807-2T should be reclassified as Infirmifilum uzonense strain 1807-2T comb. nov. Finally, based on phylogenomic and comparative genome analyses of representatives of Thermofilaceae family and other representatives of Thermoproteales order, a proposal of transfer of the family Thermofilaceae into a separate order Thermofilales ord. nov. was made.

When Opportunity Strikes: A Case of a 67-year-old with History of Cardiac Transplant Developing New-onset Seizures

Introduction Many known risks are associated with cardiac transplantation. Although dangers surround the transplant itself, immunosuppression increases the vulnerability to infection and malignancy. Without expertise in transplant medicine, diagnosing and managing patients with complications of immunosuppression can become challenging. Case Description : A 67-year-old male 4 months post orthotopic heart transplant (OHT), without induction therapy, tolerating appropriate immunosuppression and antimicrobial prophylaxis presented to an outside hospital (OSH) for new-onset seizures and fevers of up to 104° F. At the OSH he was started on Keppra and underwent a brain MRI showing enhancing masses with edema, suspicious for metastatic disease with primary lung carcinoma, as the patient had a known lung nodule pre-OHT. The OSH called us for transfer, however, the patient refused due to wanting to stay near his home to take care of his cats. However, he continued to deteriorate despite being on steroids and anti-epileptics and on day 3, he agreed to be transferred to our facility. Transthoracic echocardiogram showed normal ejection fraction, no vegetations or abscess or evidence of graft dysfunction. Repeat MRI at our institution revealed 3 ring-enhancing lesions within the supratentorial parenchyma consistent with cerebral abscesses. CT scan showed a 2.5 cm pulmonary nodule in the left lingula. Lumbar puncture indicated white blood cells and predominant neutrophils. He was originally scheduled for a lung biopsy, but pre-procedure CT revealed the lung nodule decreased in size, suggesting an infectious etiology. He began IV Meropenem and Bactrim since all evidence was suggestive of infection and not malignancy. Brain biopsy revealed the lesions were abscesses and culture demonstrated gram-positive filamentous rods, consistent with Nocardia. Linezolid was added to his current antibiotic regiment for better broader coverage. Bacterial speciation detected Nocardia cyriacigeorgica. The patient continued to improve after antibiotic initiation and was discharged to rehab. Conclusion : Immunosuppressed patients are susceptible to opportunistic infections, such as that of N. cyriacigeorgica, especially in the first year following OHT. These infections can lead to clinical manifestations that may be mistaken for malignancy at centers lacking expertise in transplant medicine. Transplant patients should be aware of the risks of chronic immunosuppression therapy and counseled to return to the implanting center for serious conditions.

Tenuifilum thalassicum gen. nov., sp. nov., a novel moderate thermophilic anaerobic bacterium from a Kunashir Island shallow hot spring representing a new family Tenuifilaceae fam. nov. in the class Bacteroidia

A novel anaerobic moderately thermophilic bacterium, designated strain 38H-strT, was isolated from a 12m deep hot spring of the Kunashir Island shore. Gram-negative cells were non-spore-forming, motile, straight or curved filamentous rods, occasionally forming loops and knots. The strain grew at 20-65°C and pH range of 4.0-9.0 with an optimum at 50°C and pH 6.5-7.0. Strain 38H-strT required 0.5-2.5% NaCl (1.5% is an optimum) for growth. It was a chemoorganoheterotroph, growing on carbohydrates (starch, pullulan, alginate, laminarin, beta-glucan) or peptide mixtures and proteins (peptone, tryptone, gelatin, and α- or β- keratins). Major products of glucose fermentation were acetate, hydrogen, and carbon dioxide. Major cellular fatty acids were iso- and anteiso-C15:0. Phosphatidylethanolamine, an unidentified phospholipid, and three unidentified polar lipids were detected in cellular lipids fractions. The quinone was MK-7. The size of complete genome of strain 38H-strT was 3.2 Mb; DNA G+C content was 38.3mol%. According to 16S rRNA gene sequence and conserved protein sequences phylogenies, strain 38H-strT represented a deeply branched lineage near the root of the class Bacteroidia. Based on phylogenetic analysis and phenotypic features the novel isolate was assigned to a novel family within the order Bacteroidales for which the name Tenuifilaceae fam. nov. is proposed. Strain 38H-strT (=DSM 100343T =VKM B-2964T) represents the first genus and species Tenuifilum thalassicum gen. nov., sp. nov.

A rare case of brain abscess caused by Actinomyces meyeri

BackgroundBrain abscesses are the rare and most severe form of actinomycosis, which usually manifests as abscesses of the occipital or parietal lobe due to direct expansion from an adjacent area, the oral cavity. In the medical literature, there are only a few reported cases of brain abscess caused by Actinomyces meyeri. In this report, we present a 35-year-old male patient who experienced an insidious headache and left-sided weakness and was diagnosed with an Actinomyces meyeri brain abscess.Case presentationA 35-year-old Nepalese man came to our institute with the primary complaint of insidious onset of headache and left-sided weakness. His physical examination was remarkable for the left-sided weakness with power 2/5 on both upper and lower limbs, hypertonia, hyperreflexia and positive Babinski sign, with intact sensory function. Cardiac examination revealed systolic murmur with regular S1 and S2, and lung examination was normal. The patient had poor dental hygiene. Biochemistry and haematology panel were normal. Urinalysis, chest X-ray and electrocardiogram revealed no abnormality. A transthoracic echocardiogram revealed mitral regurgitation. However, there was no evidence of valvular vegetation. A magnetic resonance imaging (MRI) of the brain was performed, which showed a bi-lobed rim enhancing lesion with a conglomeration of two adjoining round lesions in the right parietal parasagittal region. Perilesional oedema resulting in mass effect over the right lateral ventricle and mid-right uncal herniation with midline shift was noted. Craniotomy was performed, and the lesion was excised. Gram staining of the extracted sample revealed gram variable filamentous rods. Creamy white, moist, confluent colonies were observed after performing anaerobic culture in chocolate agar. On the gram staining, they showed gram-positive filamentous rods. Actinomyces meyeri was identified based on matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technology. Based on the susceptibilities, he was successfully treated with ampicillin-sulbactam.ConclusionsIn conclusion, Actinomyces should be considered in the differential diagnosis of brain abscess in patients with poor dental hygiene, and early diagnosis and appropriate treatment can lead to better results.

Tailoring polypropylene for extrusion-based additive manufacturing

Abstract This paper reports on the optimization of polypropylene (PP) feedstock material towards extrusion-based additive manufacturing. To achieve this, two commercially available grades of polypropylene/ethylene random copolymers (raco PP) were modified, aiming to reduce warp deformation caused by shrinkage and at the same time reduce the anisotropic property by improving the interlayer bonding quality of 3D printed parts processed by fused filament fabrication (FFF). A β-nucleating agent, several amorphous polypropylenes (aPP) and one linear low-density polyethylene (LLDPE) were selected as additive or blending component with the goal to reduce shrinkage. The polypropylene feedstock material optimization was conducted by a combination of a lab-scale filament rod processing method and utilizing printed square tubes to optimize printing performance. The achieved results demonstrate that the crystallization behavior and E-modulus of polypropylene play significant roles for warp deformation in extrusion-based 3D printed parts. The β-nucleating agent alters the crystallization behavior, even a slightly negative influence on the warp deformation was observed. The investigated polymer blend of raco PP and LLDPE shows no significant contribution to reduce warpage and impairs also the interlayer bonding. The best results were achieved by blending raco PP with selected amorphous PPs. With two aPP grades warp deformation could be drastically reduced. In addition, the interlayer bonding quality is remarkably enhanced in these blends in spite of slight decreases in stiffness and strength. In conclusion, the optimized PP feedstock material features less warp deformation, high stiffness, and most importantly, outstanding interlayer bonding qualities.

Completion of the Vimentin Rod Domain Structure Using Experimental Restraints: A New Tool for Exploring Intermediate Filament Assembly and Mutations

Electron paramagnetic resonance (EPR) spectroscopy of full-length vimentin and X-ray crystallography of vimentin peptides has provided concordant structural data for nearly the entire central rod domain of the protein. In this report, we use a combination of EPR spectroscopy and molecular modeling to determine the structure and dynamics of the missing region and unite the separate elements into a single structure. Validation of the linker 1-2 (L1-2) modeling approach is demonstrated by the close correlation between EPR and X-ray data in the previously solved regions. Importantly, molecular dynamic (MD) simulation of the constructed model agrees with spin label motion as determined by EPR. Furthermore, MD simulation shows L1-2 heterogeneity, with a concerted switching of states among the dimer chains. These data provide the first ever experimentally driven model of a complete intermediate filament rod domain, providing research tools for further modeling and assembly studies.

Imaging Findings of Pulmonary Nocardiosis Mimicking Bronchiectasis.

Nocardia species usually cause opportunistic infections, and the frequency of these infections is increasing owing to the growing population of immunocompromised hosts. However, Nocardia may sometimes causes an infectious disease in immunocompetent hosts. Herein, we report two cases of pulmonary nocardiasis in immunocompetent individuals, whose chest computed tomography (CT) findings mimicked bronchiectasis. Samples of bronchalveolar lavage (BAL) fluid obtained by bronchoscopy showed filamentous, branching, gram-positive rods, acid-fast filamentous branching rods, and a colony of suspected Nocardia was cultured. Based on 16sRNA and hsp65 gene sequence analysis, case 1 was identified as N. cyriacigeorgica, but case 2 was not matched. The patients responded well to treatment with the combination of sulfamethoxazole and linezolid.

Filamentous rods in the cerebrospinal fluid of a child with ventriculoperitoneal shunt: “Separation Anxiety” at the microscopic level!

Certain bacteria and antibiotic combinations can result in unusual morphologic transformations such as the creation of septate filamentous bacterial rods, where division is preserved, but separation is inhibited. This is often seen when subinhibitory concentrations of antibiotics are administered. Herein, we describe this phenomenon in the case of a teenage boy with an infected ventriculoperitoneal shunt, whose culture-proven Pseudomonas aeruginosa took on a filamentous appearance following antibiotic treatment. This transformation is important to recognize, so it is not misconstrued as fungal hyphae, committing the patient to unnecessary treatment.