Test Tube Method Research Articles

Isolation and Antibacterial Activity of Sembung (Blumea balsamifera) Leaf Essential Oil L., DC

Sembung leaf essential oil is a complex mixture in the form of oily yellow liquid with a unique aroma. It contains various volatile components that have antibacterial, antifungal, antioxidant and cytotoxic activities. This study aims to determine the antibacterial activity of essential oil Blumea balsamifera L., DC against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Isolation of essential oil using steam distillation method with 0.21% rendement. Inhibition activity was performed by test tube method with variation concentrations of essential oil were 10%, 20%, 40%, 80%, and 100% for each bacteria. Results of this study showed that the highest antibacterial activity on Escherichia coli at 80% concentration with an inhibition zone diameter of 27.53 mm, 100% concentration for Pseudomonas aeruginosa with an inhibition zone diameter 25.72 mm and 100% concentration for Staphylococcus aureus with inhibition zone diameter 27.31 mm. Essential oil from (Blumea balsamifera) L., DC leaves have a strong activity inhibition category against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.

Analysis of RhC Antigen Weak Expression Combined with Mimicking Autoanti-Ce and Homologous Anti-Jkb Causing Mismatch

To investigate the reasons for the weak expression of RHCE gene in a patient whose mimicking anti-Ce combined with anti-Jkb caused cross-matching non-combination. ABO, Rh, and Kidd blood group antigens were identified by test tube method and capillary centrifugation. Antibody screening and antibody specificity identification were performed using saline, polybrene and antiglobulin in tri-media association with multispectral cells. RHCE gene sequencing and haploid analysis were performed by multiplex PCR technique and RHCE protein modeling was performed using Swiss-Model. The serum of the patient contained anti-Ce mimicking autoantibodies along with anti-Jkb antibodies. c.48G>C, c.150C>T, c.178C>A, c.201A>G, c.203A>G, and c.307C>T mutations were detected in the RHCE triple-molecule sequencing. A 109 bp insertion sequence was found in intron 2, with fragment loss from intron 5-8. The Rh-group genotype was DCe/DCe , and phenotype was CCDee. Genotyping techniques can assist in deducing the molecular mechanisms of some weakly expressed RhC, c, E, and e in patients' sera to aid in the identification of difficult antibodies and thus ensure the safety of patients' blood transfusion.

Increased expression of ABO blood group antigens secretion phenotype with O blood group and age advances.

To ascertain the prevalence of ABH antigen secretors and non-secretors among Yemenis. In addition to explore the factors that may affect the expression of the secretion phenotype. This cross-sectional study was carried out between May and September 2022 on 215 healthy Yemeni individuals at the International Malaysian University, Ibb, Yemen. The participants were tested for blood group antigen on their blood samples using standard test tube method using the suitable ABH antisera. Saliva was collected and tested for secretion using hemagglutination inhibition test with suitable A, B, and H antisera. Before collecting the blood samples, informed consent was obtained from each participant and complete data and history questionnaire were collected by the research team. In general, 78.1% of Yemini participants were found to be secretor (80% men and 73.3% females). This percentage increased within O blood group (95%) and decreased within AB blood group (54%) individuals. Both O and AB blood groups showed statistically significant association with secretor trait. Also, it was noticed that age advance increases the expression of Se gene. In addition, the secretor state increased among Rh-negative people. The frequency of ABH secretors was 78.1% among Ibb province population in Yemen. Blood group O revealed the greatest frequency (95%), whereas blood group AB showed the lowest secretor frequency (54%). The secretor phenotype was highly expressed gradually with advance age then decline.

Comparison of Actual Blood Type with Blood Type in Indonesian Identity Card of Pekayon Village- East Jakarta Residents in 2022

Among the public, the knowledge of ABO blood type is not well understood. Many people in Indonesia do not know their blood type but they have to state their blood type for the Indonesian Identity Card at the civil registration services. To compare the actual blood type of Pekayon village-East Jakarta residents with the blood type in Indonesian Identity Card in 2022. The research is a cross-sectional study of 100 residents at Pekayon Village-East Jakarta in 2022. We did ABO blood grouping with tube test method then compared the results as actual blood type with the resident’s blood type in their Indonesian Identity Card. The blood type of the residents at Pekayon Village-East Jakarta are 39% blood type O, 33% blood type A, 20% blood type B and 8% blood type AB. The actual blood type matched with the blood type in Indonesian Identity Card were 43% and 57% did not match because previously when the residents stated the blood type for Indonesian Identity Card not based on actual blood type. The actual blood type were mostly different with the actual blood type of residents at Pekayon Village-East Jakarta in 2022. The Indonesian citizen should state the correct blood type for Indonesian Identity Card based on blood grouping result.

Molecular biological identification of a case with A223B subtype

To study the molecular basis for a proband with A subtype B of the ABO blood group and explore the influence of amino acid variant on the activity of glycosyltransferase (GT). A proband who had presented at the First Affiliated Hospital of Zhengzhou University on July 2, 2020 was selected as the study subject. Serological identification of the ABO blood groups of the proband and her family members were performed by gel card and test tube methods. The ABO gene of the proband was identified by PCR-sequence specific primers (PCR-SSP) and DNA sequencing. A 3D molecular homologous model was constructed to predict the impact of the variant on the stability of α-(1→3)-D-N-acetylgalactosamine transferase (GTA). The red blood cells of the proband, her mother and two younger brothers showed weak agglutination with anti-A and strong agglutination with anti-B. The sera showed 1~2+ agglutination with Ac and no agglutination with Bc. Based on the serological characteristics, the proband was identified as AwB subtype. Pedigree analysis suggested that the variant was inherited from her mother. The blood group of the proband was identified as A223B type by PCR-SSP. ABO gene sequencing analysis showed that the proband has harbored heterozygous variants of c.297A>G, c.467C>T, c.526C>G, c.657C>T, c.703G>A, c.796C>A, c.803G>C, c.930G>A and c.1055insA. Based on the results of clone sequencing, it was speculated that the genotype was ABO*A223/ABO*B.01. There were c.467C>T and c.1055insA variants compared with ABO*A1.01, and c.1055insA variant compared with ABO*A1.02. Homologous modeling showed that the C-terminal of A223 GT was significantly prolonged, and the local amino acids and hydrogen bond network have changed. Above results revealed the molecular genetics mechanism of A223B subtype. The c.1055insA variant carried by the proband may affect the enzymatic activity of GTA and ultimately lead to weakening of A antigen.

Evaluation of the antibacterial effect of (R)-(+)-Limonene against Enterococcus faecalis and Enterobacter cloacae strains isolated from food

The aim of this study was to evaluate the potential antibacterial and anti-adherent activities of the monoterpene (R)-(+)-limonene, as well as its synergistic potential with synthetic antimicrobials against strains of Enterococcus faecalis and Enterobacter cloacae. The antibacterial properties of (R)-(+)-limonene were assessed using the broth microdilution technique to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Additionally, the infusion disc method was employed to explore the association of the compound with antimicrobials, and the test tube method was used to determine the minimum inhibitory concentration of adherence (MICA). It was observed that the MIC for (R)-(+)-limonene was 1000 μg mL-1 for five of the six E. faecalis strains tested, while for E. cloacae, the MIC exceeded 1000 μg mL-1 for all strains tested. Identical values were recorded for the MBC in E. faecalis. In terms of its combination with synthetic antimicrobials, (R)-(+)-limonene demonstrated a synergistic effect with gentamicin and ciprofloxacin for most strains. Regarding the MICA, both (R)-(+)-limonene and 0.12% chlorhexidine digluconate failed to inhibit biofilm formation at the tested concentrations. Given the need for new therapeutic alternatives for treating bacterial infections, this study revealed that the tested monoterpene exhibited moderate bactericidal effects against E. faecalis strains and no antibacterial effect against E. cloacae strains. However, when combined with various classes of antimicrobials, (R)-(+)-limonene showed synergistic effects with gentamicin and ciprofloxacin for most strains. This suggests that (R)-(+)-limonene holds promise for enhancing the treatment of bacterial infections and could support conventional therapies. Nonetheless, further in vitro, ex vivo, and in vivo studies are necessary to confirm and elucidate its efficacy and mechanisms.

Comparative Analysis of a Secondary Metabolite Profile from Leaves, Peel and Bulbs of Allium sativum L. by GC-MS

Garlic is a herbal plant that is widely used as a medicinal ingredient, because it contains secondary metabolite compounds such as alkaloids, flavonoids, tannins, phenols, terpenoids and saponins. The secondary metabolite content of plants is influenced by genetic, ontogenic, morphogenetic and environmental factors that can influence the biosynthesis and accumulation of secondary metabolites. Garlic is generally only used for the bulbs, while other parts such as the leaves and skin are still not widely used. This study aims to identify the secondary metabolite profile of ethanol extract of garlic leaves, bulbs and peels using the gas chromatography mass spectrometry (GC-MS) method. Identification of secondary metabolite compounds contained in each 70% ethanol extract was analyzed using the tube test, thin layer chromatography (TLC) and GC-MS methods. The results of analysis of secondary metabolite content using the tube test and TLC method showed that the ethanol extract of garlic leaves, skin and bulbs positively contained flavonoids, tannins, phenols and saponins. The results of secondary metabolite profile analysis using the GC-MS method from the ethanol extract of garlic skin and bulbs showed that 5 compounds were obtained with the main compound being 3,4-Dihydroxyphenylacetic acid and 23 compounds with the main compound being 1,2-Benzenedicaboxylic acid and palmitic acid, while the leek extract white only detected 1 compound. The conclusion is that the ethanol extract of garlic leaves, skin and bulbs has secondary metabolites in the form of flavonoids, tannins, phenols and saponins. There are differences in the profile of secondary metabolite compounds in the ethanol extract of garlic leaves, skin and bulbs in terms of the results of GC-MS analysis.

'Old is gold' does conventional test tube method still reign supreme? An immuno-haematological survey of anti-D detection and titration in ante-natal cases among major hospitals across India.

Anti-D detection and titration plays a major role in RhD negative antenatal cases both, for monitoring maternal as well as fetal status as well as initiation of early therapeutic interventions, such as intra-uterine transfusions (IUT) to improve maternal as well as fetal morbidity and mortality and reduce the adverse effects of haemolytic disease of fetus and newborn (HDFN). We conducted a survey focusing on the policies and procedures of anti-D detection and titration among major tertiary care centres across India. The survey was drafted by a working group of transfusion medicine and immunohematology specialists from six different centres in India. Data were obtained via the use of an online questionnaire. Results were categorised into four categories, Hospital information, immuno-haematological testing methodology, clinical significance of anti-D testing and the role of transfusion medicine specialists. The survey highlighted the modalities as well as the methodologies of anti-D detection and titration in antenatal women across different major tertiary care centres in India. This survey provided a unique snapshot of the prevalent methodologies being employed by major tertiary care centres across the country for detection and titration of anti-D levels as well as the important role it plays in the therapy of affected antenatal women to minimise adverse effects on the fetus.

Warm reactive autoantibodies detected by solid phase technology: Patient characteristics, laboratory features, and clinical significance.

This study focused on the serology, clinical characteristics, and hemolytic potential of warm reactive autoantibodies detected by solid phase red cell adherence. Ninety-seven patients with warm autoantibodies were evaluated. Serologic characteristics included the strength of solid phase reactivity, the results of tube-based ancillary testing, direct antiglobulin test and eluate results, and an assessment for contemporaneous alloantibodies. Clinical characteristics of the patients included age, sex, and primary diagnosis. Each patient was also assessed for evidence of hemolysis. Most of the 97 study patients were female (63.9%), and the average age was 66 years. Hematologic disorders were the most common diagnosis. A majority (70.1%) of the warm autoantibodies had 3 to 4+ reaction strengths, and approximately 90% had negative testing with at least 1 test tube method. There was an even distribution of direct antiglobulin test reaction strengths, with 74% reactive with anti-immunoglobulin G only. Alloantibodies were identified in 20% of patients. Evidence of hemolysis was identified in only 13 patients (13.4%). Warm reactive autoantibodies are more likely to be hemolytic, have strongly reactive indirect and direct antiglobulin tests, remain reactive in tube-based ancillary testing methods, and are seen primarily in patients with hematologic disorders.

Colloidal interaction of fly ash and soil clay

The combustion of coal worldwide creates a large quantity of fly ash (FA), and the application of FA to agricultural soils is being encouraged as a resource utilization strategy. While most of our attention has focused on positive aspects such as nutrient supplementation and pollution mitigation, the negative impacts of FA have likely been overlooked. In this study, we examined the colloidal properties of FA and soil clay, aiming to demonstrate the ability of FA to increase the dispersibility and transportability of soil clay. Dynamic light scattering technique was coupled with the test tube method to track the kinetics and pH-dependent changes in the zeta potential, hydrodynamic size and colloidal stability of FA, soil clay and their mixtures. We found that FA occurred in solution as “negatively charged balls”, and its negative surface charges increased with increasing pH. FA itself showed a low dispersibility; however, FA became more dispersive when it was introduced to clay suspensions. The mechanism is that the introduction of FA supplied more negative charges to the clay suspension, inducing electrostatic repulsion with soil clay, from which both FA and soil clay were favoured to disperse. Therefore, it can be inferred that off-site transport of FA is possible. More importantly, excessive application of FA can inadvertently intensify clay dispersibility, eventually resulting in soil clays together with FA being more vulnerable to leaching and/or surface run-off erosion. This suggests that the application of FA needs more careful consideration, and the development of more suitable techniques for the sustainable application of FA is still needed.

A Study of A1 and A2 Subtypes Among Whole-Blood Donors With Blood Groups A and AB at the Blood Center of a Tertiary Care Institute in Chhattisgarh.

The ABO blood group shows various subtypes due to the heterogeneity of A and B alleles. The frequency of these subtypes varies in different populations. Studies related to the frequency of subtypes of blood groups A and AB are lacking in this region. So, we planned this study to estimate the prevalence of A1and A2 subtypes among the healthy blood donor population. This was a prospective study performed in the blood center of a teaching hospital in the Chhattisgarh state. Healthy whole-blood donors were included in the study after written informed consent. The conventional test tube method was used for performing forward and reverse blood grouping. Testing with anti-A1 and anti-H lectin was performed in blood groups A and AB. Additional tests such as saliva testing for secretor status and adsorption-elution were performed if needed. Four thousand one hundred twelve donor samples were studied, out of which 1170 showed A antigen. Among 1170 samples, 74.6% were blood group A, and 25.4% were AB. Among blood group A, 92.3% were A1and 3.3% A2,and the rest were other subtypes, while in AB, it was 85.2% A1B and 14.8% A2B. Two cases of anti-A1 antibodies were also noted, which were clinically insignificant. We observed a significantly higher proportion of A2B than A2 in our study population. We also found a large proportion of Aint in the study participants. Testing with anti-A1 andanti-H lectin is recommended in blood groups A and AB to determine various subtypes and prevent any incompatibility.

Design and construction of the Texas Christian University impedance tube

The two-microphone impedance tube test method is a well-established and widely used technique for determining the acoustic absorption coefficient and impedance ratio of materials. This method uses two closely spaced microphones to simultaneously measure the incident and reflected sound waves. A two-microphone impedance tube measurement system made of 6061-T6 Aluminum with a diameter of 3 inches, a 0.5 inch wall thickness, and microphones spaced 2.7 inches apart has been constructed for undergraduate research at Texas Christian University (TCU). These geometrical values suggest a usable frequency range of 50 Hz to 2637.77 Hz as referenced in ASTM Standard E1050-19. Validation of the system was achieved by taking measurements on Owen Corning Type 705 pressed fiberglass board with a 1-inch thickness and comparing them to absorption data provided by the manufacturer. Additional validation measurements were taken without a test sample in place. All validation tests suggest that the TCU impedance tube is an accurate measurement system.

Study of biofilm formation among uropathogens isolated from catheter-associated UTI patient from a tertiary care hospital

Background: Catheter-associated urinary tract infection (CAUTI) is a serious health threat and challenging infection. CAUTI accounts for up to 40% of all nosocomial infections. Biofilm provides a survival strategy to microorganisms and ultimately leads to re-infections and recurrence of urinary tract infections (UTI) despite a full course of antibiotics. Aims and Objectives: The present study was conducted to determine the prevalence of CAUTI in suspected UTI patients and prevalence of biofilm-forming uropathogens among CAUTI patients. Materials and Methods: The cross-sectional study was done over a period of 6 months among 95 catheterized CAUTI patients. Biofilm production among isolated uropathogens was tested by tissue culture plate, tube test, and congo red agar method. Isolates were identified as biofilm producer if they were tested positive by any one of the all four methods, and isolates were considered biofilm non-producer in consensus with all four methods. Results: In this study, the prevalence of CAUTI was 68.42%. Among 65 isolates most common uropathogen was 28 (43.07%) Escherichia coli. In this present study, the prevalence of biofilm-forming uropathogens was 58.46% (38). Tissue culture plate was the most sensitive (97.36%) method in detecting biofilm formation followed by modified congo red agar (82.21%), congo red agar (71.05%), and tube test (65.78%). Biofilm productions were significantly associated with female gender, diabetes, and prolonged catheterization. Conclusion: Indwelling urinary catheter acts as a nidus for biofilm formation among microorganisms. Duration of catheterization is inversely associated with UTI. Hence, the need for catheter removal should be assessed daily to prevent infection. Periodic surveillance should be done to detect biofilm formation where prolonged catheterization is inevitable.

Emerging antibiotic resistance in Plesiomonasshigelloides: insights from surface waters in Southwest Nigeria

Abstract This study aimed to investigate the antibiotic resistance pattern, extended-spectrum β-lactamase (ESBL) production, and biofilm formation potential of Plesiomonas shigelloides in selected surface waters in southwestern Nigeria. Isolates were identified using the spread plate technique on inositol brilliant green bile agar and confirmed molecularly by polymerase chain reaction. Antibiotic susceptibility was determined using the Kirby–Bauer disc diffusion method, ESBL production by the double disc synergistic test, and biofilm formation by the test tube method. A total of 111 P. shigelloides isolates were identified and confirmed. Significant resistance rates were observed against cefuroxime (71%), cefotaxime (92%), and ceftazidime (92%), while high susceptibility was noted for ciprofloxacin (94%), gentamicin (96%), and chloramphenicol (100%). A higher prevalence of multiple drug resistant phenotypes was observed during the dry season, reaching 79% and 60% along sampled rivers. Biofilm-producing phenotypes exhibited robust homogeneous biofilm formation. In this study, P. shigelloides exhibited high resistance to critical antibiotics such as third-generation cephalosporins. However, isolates displayed susceptibility to ciprofloxacin, gentamicin, and chloramphenicol. The presence of ESBL phenotypes and strong biofilm formation emphasizes the potential threat of P. shigelloides as an emerging environmental pathogen, highlighting the importance of monitoring and understanding antibiotic resistance patterns for effective public health management strategies.

Association Between Biofilm Formation by U.P.E.C. and Serum Level of Several Cytokines

One hundred and eighty-nine subjects from Baghdad enrolled in this study (110 female and 79 male) and gathered into two investigated groups; the first group consisted of 149 patients, and the second group consisted of 40 healthy individuals. Results revealed after clinical laboratory diagnosis of urine samples 12 (8.1%) gave a negative bacterial culture, 137 (91.9%) were positive culture, while all urine samples of healthy control were negative. Gram staining and microscopic examination of bacterial colonies showed that 11(8.03%) out of 137 isolates were identified as Gram-positive and 126 (91.97%) as Gram-negative. After biochemical analysis and diagnosis by the Vitik system, the data demonstrated that a single infectious agent caused all U.T.I. cases. U.P.E.C. represented the most common bacterial agent because of several virulence factors responsible for its pathogenicity. The test tube method and Congo red agar medium have been used to detect biofilm formation. Results demonstrate that 129 (94.16 %) of bacterial isolates were producers, while just 8 (5.84 %) were non-producers. The results of the microtiter plate method revealed that the isolates were categorized into four groups: Strong, moderate, weak, and harmful. 22 (63.5%) were strong biofilm producers, 28 (20.449%) were moderate producers, 14 (10.22%) were weak producers, and 8 (5.84%) were unable to form biofilm. Serum levels of IL-1β, IL-6 and IL-8 were estimated by Sandwich ELISA, which were significantly higher in patients with different types of U.T.I.s than the healthy group. This study concluded that the U.P.E.C. represented the most common prevalent agent of U.T.I.s and more efficient biofilm-producer bacteria. The test tube method is the best qualitative, quick, and easy detection method of biofilm formation, while the microtiter plate is the best quantitative and sensitive method. A positive correlation was found between biofilm formation and elevated serum levels of proinflammatory cytokines, proportionally increased with advanced and severe, especially in old persons. Keywords: UTIs; ELISA; IL-1β; IL-6; IL-8; Iraq

Aktivitas antioksidan dan uji sitotoksik infusa daun jarak pagar (Jatropha curcas)

Antioxidants are crucial in preventing cell damage caused by oxidation from oxidants. The use of antioxidants from natural products such as Jatropha curcas leaves can counteract free radicals due to the presence of secondary metabolites. The main aims of the study were to determine the antioxidant and cytotoxic activity of the infusion of J. curcas leaves. The sample was extracted using the infusion method. A qualitative phytochemical screening was carried out using the test tube method, antioxidant assay using the DPPH method and cytotoxic using the BSLT method. The results showed that the infuse of J. curcas leaves contained secondary metabolites such as polyphenols and tannins, alkaloids, flavonoids, and saponins. In the antioxidant activity test, infuse of J. curcas leaves and vitamin C (control) the IC50 was 58.90±2.34 ppm and 8.78±0.21 ppm respectively. The infused cytotoxic test contained an active toxic compound in shrimp larvae with an LC50 of 200.28 ppm (LC50 ≤ 1000 ppm). Based on the results of the study, infuse of J. curcas leaves showed potential as an antioxidant and anticancer agent with a strong classification.

Thickening capacity of Cordia lutea Lam mucilage gum in a liquid soap formulation

The study refers to the use of Cordia lutea Lam gum as a natural thickener in a liquid soap formulation. The aim was to determine the phytochemical components and the thickening capacity of mucilage gum in a liquid soap formula. The color of the fruit and the mucilage gum were determined by CIELab methodology, the phytochemical screening of the mucilage gum extracted by manual pressure, by rapid chemical reactions. The hydrocarbons were determined by gas chromatography and the viscosity using a rotational viscometer. Liquid soap was made according to a commercial formula using a DCA design along with the factors amount of mucilage and Texapon at two levels (low and high) and viscosity and foam formation that were used as response variables. The thickening effect of the mucilage gum in the soap was evidenced through the viscosity (mPa.s) and foaming capacity by the test tube method; those variables were tabulated using the statistical software statgraphics plus. Phytochemical results showed the presence of saponins, quinones, carotenoids and coumarins; and hydrocarbon compounds: tetratriacontane (34,28%), n-hexadecanoic acid (28,74%) and 9-12-15-Octadecatrienoic acid (18,19%). The viscosity of the mucilage gum was greater than 14000 mPa.s and that of the liquid soap that ranged from 1931 to 2822 mPa.s. The pH was 6,5 to 6,8 and the foaming was comparatively higher than commercial products. The mucilage gum obtained constitutes a natural thickener with an important projection of immediate application in the pharmaceutical and cosmetic industries.

Iron Oxide Nanoparticles as Anti-Virulence Factors of Gram-positive and Gram-negative Bacteria

Background: Due to their extensive use in medical therapy, iron oxide nanoparticles have recently attracted the attention of researchers in the field of increasing multi-resistance properties in bacterial pathogens. Because iron oxide nanoparticles have a high specific surface area, they can interact with bacterial surface structures and exhibit significant antibacterial activity. Objective: The current work, determined the effect of a novel anti-virulence factor agent which was created from iron oxide nanoparticles against selected gram-positive and gram-negative variant bacterial strains that were isolated and identified from elderly Iraqi patients with urinary tract infections. Methods: Seven bacterial strains (three gram-positive and four gram-negative) were tested for their (biofilm, adhesion, and hemolysis) activity using the quantitative test-tube method, glass-slide method, and by determining the hemolysis ability of bacterial isolates against previously prepared RBC, respectively. The highest virulence factors formation bacterial isolates were chosen to determine the effect of Iron-oxide nanoparticles. Previously prepared and characterized Iron- oxide nanoparticles were used as anti- (biofilm, adhesion, and hemolysis) by using specific Bacterial-Fe3O4 NPs complex with different concentrations. The Results: All these bacteria expressed their virulence factors, the highest-level biofilm formation abilities were detected in Proteus mirabilis and Staphylococcus aureus, and the highest-level adhesion activity was observed in Enterococcus faecalis and Pseudomonas aeruginosa while the highest-level hemolysis activities on human RBC were determined in Micrococcus luteus and E. coli. The effects of (Fe3O4) nanoparticles against the highest virulence factors bacterial isolates shows an increases in the biofilm formation abilities of S. aureus and P. mirabilis as well as for standard bacterial strains the anti-biofilm formation ability of (Fe3 O4) NPs against gram-positive S. aureus, Proteus mirabilis, and standard gram-negative bacteria demonstrated an in-decrease biofilm formation ability of these bacteria effective at (5000 and 10000 µg/ml). The anti-adhesion ability of (Fe3 O4) NPs against gram-positive Enterococcus faecalis, and gram-negative Pseudomonas aeruginosa determined no effect on the adhesion abilities of gram-positive and negative bacteria atall concentrations (250, 400, 500, 750 and 1000µg/ml) Finally, the effect of different concentrations of iron oxide nanoparticles on the hemolysis ability of Micrococcus luteus and Escherichia coli on RBC was determined, the highest hemolysis inhibition level was estimated in 1000 µg/ml and the less inhibition in 500 µg/ml as compared with control.

Thiourea-based low molecular-mass organogelators from (+)-dehydroabietylamine

Three new thiourea-based thermo-reversible, low molecular weight organogelators (LMOGs) 3-5 have been synthesized using (+)-Dehydroabietylamine (DAA, a tricyclic diterpene) employing DLS (Diterpene-Linker-spacer) strategy. (+) DAA was converted into isothiocynates through a cascade of reactions and cross-coupled with primary amines to furnish thiourea 3-5 with respective spacers. The structures of gelators 3-5 were confirmed through 1H-NMR and 13C-NMR spectroscopy, high-resolution electron spray ionization mass spectrometry (HRESI–MS, positive mode) and FTIR spectroscopy. Gelation potential of gelators 3-5 was investigated through inverted test tube method and sol–gel transition measured by ball-dropping method. The results revealed that unbranched alkyl groups furnish gelation and their gelation ability increases with increasing spacer length. Gelator 5 with dodecyl chain found to be excellent gelator that can gelate hexane (spontaneously), toluene, methanol, ethanol, petrol, and diesel. Morphology of gels was studied though scanning electron microscopy exhibiting fibrillar to lamellar structure with a thickness in the range of 9.5 nm to 5.0 μm with increasing length of spacer.

Additively manufactured spinodoid sound absorbers

Spinodoid structures, also called spinodoid metamaterials, are non-periodic cellular structures that mimic spinodal topologies that are observed during diffusion-driven phase separation processes. Computationally efficient to model, spinodoid structures can be fabricated using additive techniques and offer an attractive route to the design of multifunctional structures. In this paper, we investigate the normal incidence sound absorption behavior of four distinct spinodoid topologies: isotropic, cubic, columnar, and lamellar. We fabricate the test samples using the fused filament fabrication process and systematically study the effect of the Gaussian Random Field (GRF) parameters on their underlying open pore network and sound absorption behavior. We employ a watershed segmentation-based image processing approach to correlate their pore and throat radii distributions to the GRF parameters. The normal incidence sound absorption properties are experimentally measured using the two-microphone impedance tube test method. Finally, we use a particle-swarm-based inverse characterization approach to extract the bulk properties necessary to model their acoustical behavior by using the Johnson-Champoux-Allard formulation. Our results show that the open pore network and acoustical properties of spinodoid structures are primarily a function of their relative density and wavenumber. Further, while the absorption behavior of the isotropic, cubic, and columnar spinodoids is similar, the lamellar spinodoids display unique low-frequency sound absorption behavior. Overall, all four spinodoid topologies provide favorable sound absorption characteristics, which may be tuned by varying the GRF parameters. The presented work advances the state-of-the art by establishing the feasibility of using additive manufacturing to enable non-periodic porous structures for that can be tuned to simultaneously provide mechanical stiffness and noise dampening capabilities.