Susceptibility Data Research Articles

Assessing antimicrobial stewardship governance in Northeast Brazilian hospitals: a survey-based analysis.

Effective governance of antimicrobial stewardship (AMS) and infection prevention control (IPC) in healthcare facilities is crucial for safeguarding patients against healthcare-associated infections and enhancing patient outcomes by optimizing antibiotic use and curbing the spread of antimicrobial-resistant (AMR) pathogens. To assess the current AMS governance in two public hospitals in Northeast of Brazil, specifically focusing on identifying institutional antibiotic policies and operational practices. A survey was conducted by team leaders of both hospitals from 2020 to 2022 using a questionnaire adapted from the Pan American Health Organization (PAHO) recommendations for implementing AMS programmes (ASP) in Latin America and the Caribbean, alongside criteria from the National Health Surveillance Agency (ANVISA) and CDC. Fifty leaders, from senior management to coordinators, answered the questionnaire. Results indicate a lack of AMS process measures, specialist support, systematic antimicrobial utilization analysis and structured IPC programmes, especially in one hospital where patient records remain in paper format. The empirical use of antimicrobials without local epidemiological or susceptibility data underscores the absence of logistical support for microbiological cultures in the region. These findings emphasize the urgent need for systematic AMS processes and multiprofessional teams to drive AMS and IPC practices, essential for patient care and safety.

Patient characteristics and antimicrobial susceptibility profiles of Escherichia coli and Klebsiella pneumoniae infections in international travellers: a GeoSentinel analysis.

Antimicrobial resistance (AMR) is a global health crisis, with Enterobacterales including Escherichia coli and Klebsiella pneumoniae playing significant roles. While international travel to low- and middle-income countries is linked to colonisation with AMR Enterobacterales, the clinical implications, particularly the risk of subsequent infection, remain unclear due to limited data. We aimed to characterise E. coli and K. pneumoniae infections in travellers and the antimicrobial susceptibility profiles of their isolates. We analysed data on E. coli and K. pneumoniae infections in travellers collected at GeoSentinel sites between 2015 and 2022, focusing on epidemiological, clinical and microbiological characteristics. We defined multi-drug resistance (MDR) as non-susceptibility to agents from at least three drug classes. Over the 8-year period, we included 655 patients (median age 41years; 74% female) from 57 sites in 27 countries, with 584 E. coli and 72K. pneumoniae infections. Common travel regions included Sub-Saharan Africa, Southeast Asia, and South-Central Asia. Urinary tract infections predominated. Almost half (45%) were hospitalised. Among infections with antimicrobial susceptibility data across three or more drug classes, 203/544 (37%) E. coli and 19/67 (28%) K. pneumoniae demonstrated MDR. Over one-third of E. coli and K. pneumoniae isolates were non-susceptible to third-generation cephalosporins and cotrimoxazole, with 38% and 28% non-susceptible to fluoroquinolones, respectively. Travellers to South-Central Asia most frequently had isolates non-susceptible to third-generation cephalosporins, fluoroquinolones and carbapenems. We observed increasing frequencies of phenotypic extended spectrum beta-lactamase and carbapenem resistance over time. E. coli and K. pneumoniae infections in travellers, particularly those to Asia, may be challenging to empirically treat. Our analysis highlights the significant health risks these infections pose to travellers and emphasises the escalating global threat of AMR. Enhanced, systematic AMR surveillance in travellers is needed, along with prospective data on infection risk post travel-related AMR organism acquisition.

Molecular and Epidemiological Characterization of Pediatric and Adult C. difficile Infection in Canadian Hospitals, 2015-2022

Background: The molecular and epidemiological landscape of C. difficile infection (CDI) has evolved markedly in the last decade; however, limited information is available contrasting differences between adult and pediatric populations. We describe a multicenter study evaluating healthcare-associated (HA) and community-associated (CA) adult and pediatric-CDI identified in the Canadian Nosocomial Infection Surveillance Program (CNISP) network from 2015 to 2022. Methods: Hospitalized patients with CDI were identified from up to 84 hospitals between 2015–2022 using standardized case definitions. Cases were confirmed by PCR, cultured, and further characterized using ribotyping and E-test. We used two-tailed tests for significance (p≤0.05). Results: Of 30,817 cases reported, 29,245 were adult cases [HA-CDI (73.2%), CA-CDI (26.8%)] and 1,572 were pediatric cases [HA-CDI (77.7%), CA-CDI (22.3%)]. From 2015 to 2022, HA-CDI rates decreased 19.7% (p=0.007) and 29.4% (p=0.004) in adult and pediatric populations, respectively (Figure 1). CA-CDI rates remained relatively stable in the adult population (p=0.797), while decreasing 60.7% in the pediatric population (p=0.013). Median ages of adult and pediatric patients were 70 (interquartile range (IQR), 58–80) and seven (IQR, 3–13) years, respectively. Thirty-day all-cause mortality was significantly higher among adult vs. Pediatric CDI patients (11.0% vs 1.4%, p < 0.0001). No significant differences in other severe outcomes were found. Ribotyping and susceptibility data were available for 4,620 samples: 3,558 adult (77.0%) and 1,062 pediatric (23.0%). The predominant adult and pediatric ribotypes (RT) were 106 (12.2/16.2%), 027 (11.4/3.2%), and 014 (8.8/8.2%). Overall, RT027 prevalence significantly decreased from 17.9% in 2015 to 3.2% in 2022 (p=0.003), while RT106 increased from 8.5% to 14.4%. Resistance rates among adult and pediatric isolates were similar for all antimicrobials tested except moxifloxacin (16.2% vs. 6.2%, p < 0.0001, respectively). Adult moxifloxacin resistance decreased from 30% to 6.3% from 2015 to 2022 (p=0.006). Adults with moxifloxacin-resistant CDI were older (median: 74 vs. 69 years, p < 0.001) and had higher thirty-day all-cause mortality (13% vs. 9.8%, p=0.041) and recurrence (10% vs. 5.7%, p < 0.001) compared to those with moxifloxacin non-resistant CDI, while these trends were not observed in pediatric patients. Among RT027 strains, moxifloxacin resistance decreased from 91.0% in 2015 to 7.1% in 2022. There was one metronidazole-resistant pediatric sample in 2018 and no resistance to vancomycin or tigecycline in either population. Conclusion: We have found differences in the epidemiological and molecular characteristics of adult and pediatric CDI, with higher thirty-day all-cause mortality among adults. Overall, RT106 has replaced RT027 as the predominant ribotype with a concomitant decrease in fluoroquinolone resistance.

Antibiotic Resistance Pattern of Bacteria Isolated from Clinical Specimens: A Hospital-Based Cross-sectional Study in Kathmandu, Nepal

Antibiotics are vital in combating infectious diseases, yet their increasing use fosters resistance. Antimicrobial resistance (AMR) is rising in Nepal due to factors such as indiscriminate, inappropriate, and inadequate antibiotic usage. This study aims to explore the association between demographic factors and the prevalence of specific bacterial strains within the surveyed population. Additionally, it seeks to determine the antibiotic resistance patterns of these bacteria. Antibiotic susceptibility or resistance data were retrieved from the Medical Records Department (MRD) of the Manmohan Memorial Medical College and Teaching Hospital (MMMCTH) in Kathmandu. Samples from patients with certain types of bacterial infections were included, with 56 from sputum reports, 46 from urine, and 8 from blood samples out of 110 retrieved. Analysis revealed that sputum samples were mostly from older males, while urine samples were mostly from females. Yet, gender did not significantly influence bacterial presence across sample types. Overall, Escherichia coli was the most prevalent bacterium (74%), followed by Salmonella typhi (25%), Staphylococcus aureus (25%), and Klebsiella pneumoniae (23%) isolated from different type of clinical samples. Altogether, 6-15 antibiotics were assessed for sensitivity, with 2–6 antibiotics showing sensitivity to blood bacteria, 1-6 antibiotics demonstrating sensitivity to sputum bacteria, and 3–8 antibiotics exhibiting sensitivity to urine bacteria. Many investigated antibiotics were resistant, only gentamicin exhibited sensitivity for all types of bacteria found in blood, sputum and urine. These findings underscore the importance of discerning bacterial resistance patterns for effective antimicrobial treatment selection.

A combined tectono-climatic control on Holocene sedimentation in Ladakh Himalaya, India: Clues from Anisotropy of Magnetic Susceptibility (AMS) of lake sediments

Anisotropy of Magnetic Susceptibility (AMS) data from a ∼27.8 m thick soft sedimentary mud sequence (∼10.5–3.25 k yrs) from the Spituk Palaeolake Sequence (SPSS) of Holocene age, located in the northern bank of the Indus River in the Leh-Ladakh Himalaya, show effects of tectonic versus climate dynamics responsible for the Himalayan sedimentation. The sedimentary sequence, consisting of alternating of aeolian sand and glacio-fluvial mud flow deposits, has been subdivided into an older Last Glacier Phase I (LGP 1) and a younger Last Glacier Phase II (LGP 2), where the termination of each phase is marked by the occurrence of gravel beds of thickness ≤1 m, which were deposited due to glacial melting. The present AMS data along with previously published information on sedimentology confirm that the mudflow deposits of the LGP 1 and LGP 2 phases were deposited in a lacustrine environment under glacio-fluvial conditions. However, a weak fluvial flow towards NW and NE could have existed for the LGP 1 and LGP 2, respectively. The glacial beds terminating LGP 1 and LGP 2 appear to have formed by climatic warming and tectonic activity, respectively. Hence, the Holocene Himalayan sedimentation was influenced by both climatic and tectonic activities. However, the thickness of the gravel bed (∼0.8 m) terminating LGP 2 occupies only ∼ 2.8 vol % of the total studied thickness ∼28 m, of the SPSS in the present study, which indicated a lesser control of tectonism in the growth of the Himalaya in and around the study area.

Turbidite correlation for paleoseismology

Marine turbidite paleoseismology relies on the assumption of synchronous triggering of turbidity currents by earthquake shaking to infer rupture extent and recurrence. Such inference commonly depends on age dating and correlation of the physical stratigraphy of deposits carried by turbidity currents (i.e., turbidites) across great distances. Along the Cascadia subduction zone, which lies offshore the Pacific Northwest, USA, turbidite facies in core photographs, X-ray computed tomography images, and magnetic susceptibility (MS) data exhibit differences in character over relatively short distances, which implies that not all deposits can be correlated with confidence. Thus, subjective correlation based on expected similarity over great distances and weak age constraints does not independently support paleoseismic models. We present a new method for correlating turbidites along the Cascadia margin that can yield a more objective and repeatable stratigraphic framework to underpin earthquake recurrence. We use dynamic time warping to correlate MS logs and measure correlation coefficients of core pairs to evaluate correlation strength. We then compare these measures to a distribution of correlation coefficients of randomly generated turbidite sequences and find that only a small number of core pairs can be correlated more confidently than randomly stacked turbidites. This methodology promises a more robust correlation strategy for future stratigraphic studies.

Cefiderocol susceptibility of Achromobacter spp.: study of an accurately identified collection of 230 strains

BackgroundAchromobacter spp. are opportunistic pathogens, mostly infecting immunocompromised patients and patients with cystic fibrosis (CF) and considered as difficult-to-treat pathogens due to both intrinsic resistance and the possibility of acquired antimicrobial resistance. Species identification remains challenging leading to imprecise descriptions of resistance in each taxon. Cefiderocol is a broad-spectrum siderophore cephalosporin increasingly used in the management of Achromobacter infections for which susceptibility data remain scarce. We aimed to describe the susceptibility to cefiderocol of a collection of Achromobacter strains encompassing different species and isolation sources from CF or non-CF (NCF) patients.MethodsWe studied 230 Achromobacter strains (67 from CF, 163 from NCF patients) identified by nrdA gene-based analysis, with available susceptibility data for piperacillin–tazobactam, meropenem and trimethoprim–sulfamethoxazole. Minimal inhibitory concentrations (MICs) of cefiderocol were determined using the broth microdilution reference method according to EUCAST guidelines.ResultsStrains belonged to 15 species. A. xylosoxidans represented the main species (71.3%). MICs ranged from ≤ 0.015 to 16 mg/L with MIC50/90 of ≤ 0.015/0.5 mg/L overall and 0.125/2 mg/L against 27 (11.7%) meropenem-non-susceptible strains. Cefiderocol MICs were not related to CF/NCF origin or species although A. xylosoxidans MICs were statistically lower than those of other species considered as a whole. Considering the EUCAST non-species related breakpoint (2 mg/L), 228 strains (99.1%) were susceptible to cefiderocol. The two cefiderocol-resistant strains (A. xylosoxidans from CF patients) represented 3.7% of meropenem-non-susceptible strains and 12.5% of MDR strains.ConclusionsCefiderocol exhibited excellent in vitro activity against a large collection of accurately identified Achromobacter strains, irrespective of species and origin.

Investigation of optical and magnetic properties of 3d-4d transition metal ion based double Perovskite: Sr2MnRuO6

Investigation of physical properties in double perovskites, A2B′B″O6, containing 3d/4d transition metal ions at the B sites is an interesting avenue of research. In this study, we focus on Sr2MnRuO6, exploring its structural, morphological, optical and magnetic properties. Sr2MnRuO6 was synthesized in single phase using solid-state reaction route. It crystallizes in a tetragonal structure (space group I4/mcm, #140) with lattice parameters a = 5.4633 (2) Å, c = 7.9419 (1) Å. X-ray diffraction analysis revealed no super lattice reflections, indicating disorder in the B-site cations.The Jahn-Teller distortion in Mn-O6 octahedra,as revealed by XRD results, indicates a high spin state for the Mn3+ ion. The stoichiometric ratio of Sr: Mn: Ru (∼2:1:1), as determined by bond valence sum calculations and confirmed by energy dispersive x-ray spectroscopy agree well with the nominal composition of Sr2MnRuO6. Diffuse reflectance spectroscopy showed strong absorption throughout the visible region with a direct band gap of ∼3 eV, indicating Sr2MnRuO6 is a potential candidate for optical applications. Huge photoluminescence emission observed in the visible region is attributed to Mn3+ ions. The temperature dependence of molar susceptibility data indicates a paramagnetic to antiferromagnetic transition around 195 K. The possible super exchange paths for antiferromagnetic interaction are Ru5+- 4d3 (t2g3eg0) − O1 − Ru5+- 4d3 (t2g3eg0) along the z axis, or Ru5+- 4d3 (t2g3eg0) − O2 − Ru5+- 4d3 (t2g3eg0) in the xy-plane, with the angles between these orbitals being nearly 180°. At low temperatures under a 10,000 Oe field, spin glass type magnetic behaviour is observed. The effective magnetic moment (6.17 μB) obtained from the Curie-Weiss fit from 260 K to 290 K nearly matched with the theoretical resultant effective moment (6.24 μB) by considering Mn3+ ions in HS state and Ru5+ ions.Specific heat measurements revealed no long-range magnetic ordering down to 2 K, further suggesting the role of cationic disorder in the magnetic behaviour of Sr2MnRuO6.

Magnetic order induced by magnetic impurities in the Haldane chain compound SrNi2V2O8

Understanding the topological properties of Haldane spin systems offers promising avenues for exploring exotic quantum phases. We investigate the impact of S = 5/2 Mn2+ impurities on the magnetic properties of SrNi2V2O8, a well-known Haldane spin gapped system. Structural characterizations of SrNi2-xMnxV2O8 (x = 0.05, 0.15, 0.30 and 0.60) through Rietveld analyses of X-ray diffraction data confirm the preservation of the I41cd space group for all studied x , along with a preferential insertion of Mn2+ ions into Ni2+ sites. Magnetic susceptibility and magnetization data unveil a magnetic transition occurring in the temperature range of T = 93–99.3 K for x = 0.05–0.60. Dielectric data evince the absence of coupling between magnetic and ferroelectric phases. Notably, the magnetic ordering temperature varies little over a wide range of Mn concentrations, while notable anomalies are observed at x = 0.15. This peculiar behavior suggests that, across low-to-high concentrations, disorder-induced magnetic moments compete with the formation of spin singlets between the nearest Mn2+ impurities, which cancel out the magnetic moments.

Assessment of wound cultures in an oncology hospital

Purpose: The aim of this study is to evaluate the patient's demographic, clinical and laboratory data to determine whether the bacteria isolated from wound cultures are causative agents or colonization, and to determine their antimicrobial susceptibilities. Materials and methods: This research was conducted in XXXX between January 1, 2021 and December 31, 2022. Two hundred thirty six isolates from 186 patients wound cultures were included in the study. Demographic data, clinical data and laboratory results of the patients were evaluated. The isolated bacteria and their antimicrobial susceptibilities were determined. The Q score system was used to evaluate the microbiological quality of wound samples. Results: One hundred fifty nine cases (85%) were inpatients. Totally 119 (63.9%) patients were diagnosed with infection. The Q score for 136 samples (85.5%) was assessed as Q3. The most common isolated microorganisms were coagulase negative-staphylococci (CoNS) (19%), E.coli (14.8%), and S.aureus (13.1%), respectively in wound bacterial cultures. The methicillin resistance rate was 55.5% in CoNS and 54.1% in S.aureus. Gram-negative bacteria were isolated in 81 (59.9%) infected patients. Among the infected patients, 39 (32.7%) patients had surgical site infections, 25 (21%) prosthesis infections, and diabetic foot infections 3 (2.5%). Infection rates were statistically significantly higher in patients with surgery, prosthesis, and diabetic foot (p=0.054). Conclusion: In conclusion, Q score is a strong marker in diagnosing wound infection and excluding colonization and helps prevent unnecessary antibiotic use. Local antibiotic susceptibility data should be examined up-to-date in the empirical treatment of special patient groups such as oncological patients.

Anticipated Effects of Higher-valency Pneumococcal Conjugate Vaccines on Colonization and Acute Otitis Media.

Bacterial etiologies of acute otitis media (AOM) have shifted from the introduction of pneumococcal conjugate vaccines (PCVs), antibiotic selection and competition among species. We characterized Streptococcus pneumoniae ( Spn ), Haemophilus influenzae ( Hflu ) and Moraxella catarrhalis ( Mcat ) in the nasopharynx during well-child healthy visits and at the onset of AOM, and in middle ear fluid (MEF) of children with AOM to assess anticipated effects of higher-valency PCVs (PCV15 and PCV20). From September 2021 to September 2023, we conducted a prospective longitudinal cohort study of PCV13 immunized children 6-36 months old. MEF was collected via tympanocentesis. Serotyping and antibiotic susceptibility testing were performed on Spn , Hflu and Mcat isolates. We obtained 825 nasopharyngeal and 216 MEF samples from 301 children. The order of frequency of nasopharyngeal colonization was Mcat , Spn and Hflu ; Hflu was the predominant otopathogen in MEF. Among Spn isolates, non-PCV15, non-PCV20 serotypes predominated in the nasopharynx and in MEF; the most frequent serotype was 35B. Among MEF samples, 30% of Spn isolates were amoxicillin nonsusceptible; 23% of Hflu isolates and 100% of Mcat isolates were β-lactamase-producing. The majority of Spn isolates among young children were non-PCV15, non-PCV20 serotypes, especially serotype 35B; therefore, the impact of higher-valency PCVs in reducing pneumococcal colonization or AOM is expected to be limited. Hflu continues to be the most frequent AOM pathogen. Antibiotic susceptibility data suggest a high dose of amoxicillin/clavulanate or alternative drugs that are effective against contemporary mix of otopathogens could be considered for optimal empiric selection to provide the best efficacy.

Random singlet-like state in the dimer-based triangular antiferromagnet Ba6Y2Rh2Ti2O17−δ

We present the magnetic, thermodynamic, and muon spin relaxation (μSR) results of the dimer-based triangular antiferromagnet Ba6Y2Rh2Ti2O17−δ. The magnetic susceptibility data show the sub-Curie-Weiss behavior χ(T)∝T−αχ below 100 K, suggesting random magnetism. The isothermal magnetization results reveal the presence of weakly interacting structural orphan spins about 6.1% at 2 K, arising from the oxygen deficiency. The comprehensive μSR experiments exhibit the coexisting relaxing and nonrelaxing components along with the thermally activated behavior in the muon spin relaxation rate, reflecting the fluctuating orphan spins in the dimer singlet background. In addition, we observe the scaling behavior of M(H,T) in H/T and Pz(t) in t/HLF with the scaling exponents αχ=αM=0.75 and αμ=0.72, respectively, but not for the magnetic specific heat data. The failure of the scaling relation in Cm(H,T)/T implies low-energy excitations dressed by the conventional orphan spins. Based on these observations, we find that the magnetic ground state resembles random singlets and discuss the possible configurations of the spin dimer unit Rh2O9. Our results shed light on the role of quenched disorder in the dimer-based frustrated magnets. Published by the American Physical Society 2024

Patterns of Antibiotic Resistance in Urinary Tract Infections: A Retrospective Observational Study.

Urinary tract infections (UTIs) are among the most common bacterial infections, and antibiotic resistance complicates empiric treatment. This study aimed to describe recent resistance patterns among uropathogens in a tertiary-care teaching hospital to optimize empiric UTI management. This retrospective observational study included 280 patients diagnosed with UTIs at the Dr. Patnam Mahender Reddy Institute of Medical Sciences, Hyderabad, over a six-month period from June 2023 to November 2023. Urine culture and antibiotic susceptibility data were collected from electronic medical records. Patient demographics, including age, sex, and comorbid diabetes, were recorded. Causative uropathogens and their resistance rates to commonly prescribed UTI antibiotics were analyzed. Empiric antibiotic treatment patterns and outcomes were talked about. These included clinical cure, recurrence, susceptibility match, and microbiologic eradication. The mean age of patients was 43.5 years, with 196 (70%) being female and 70 (25%) having diabetes. Escherichia coli caused 210 (75%) of UTIs, Klebsiella pneumoniae 42 (15%), Proteus mirabilis 14 (5%), Enterococcus faecalis 8 (3%), and Staphylococcus saprophyticus 6 (2%). E. coli resistance rates were 48% for ampicillin, 25% for ciprofloxacin, 18% for trimethoprim/sulfamethoxazole (TMP/SMX), and 5% for nitrofurantoin. K. pneumoniae resistance rates were 89% for ampicillin, 67% for ciprofloxacin, 44% for TMP/SMX, and 22% for nitrofurantoin. The most frequently prescribed antibiotic was nitrofurantoin (45%), then ciprofloxacin (35%). Clinical cure was achieved in 75% of cases. Recurrent UTIs within four weeks occurred in 25% of cases. Treatment matched urine culture susceptibility in 82% of patients. The rising fluoroquinolone resistance highlights the need for current local data to guide empiric UTI treatment. Nitrofurantoin had low resistance rates and was an effective first-line therapy. Ongoing monitoring of resistance patterns in UTIs is essential to optimize antibiotic selection.

The antimicrobial susceptibility patterns of diabetic foot ulcers in the South African public healthcare sector.

Diabetic foot syndrome is defined as the presence of a diabetic foot ulcer (DFU) associated with neuropathy, peripheral artery disease and infection. While the use of antimicrobials in the treatment of DFU infection remains a mainstay, the choice of antimicrobial remains problematic owing to the presence of multidrug-resistant polymicrobial infections. In the South African public healthcare sector, the treatment of DFUs is based on the Standard Treatment Guidelines (STGs) and the Essential Drug List. These guidelines are developed using evidence-based medicine and are based on global susceptibility patterns rather than local susceptibility data, and may not provide the most appropriate treatment options. To determine the antimicrobial susceptibility patterns of DFUs isolated from patients visiting selected Gauteng provincial public hospitals in order to determine a clinically effective treatment protocol for the management of these infections. Sample swabs were taken from 51 DFUs using the Levine method. Each sample swab was spread onto blood agar plates, and thereafter individual pathogens were isolated. The antimicrobial susceptibility patterns of all isolated pathogens were determined using zone of inhibition measurements. Pathogens were grouped according to macromorphological characteristics as well as susceptibility patterns, and a representative isolate from each group was then identified. A total of 51 DFU ulcer swabs from 45 patients were included in the study. From the sample swabs, a total of 445 pathogens were isolated. The most effective antimicrobial was found to be gentamicin, followed by ciprofloxacin. Amoxicillin/clavulanic acid, the first-line treatment according to the STGs, was found to be ineffective for many of the isolated pathogens. The most commonly isolated pathogens were Proteus mirabilis, Enterococcus faecalis and Pseudomonas aeruginosa. These findings demonstrate the urgent need to reassess the STGs and base treatment plans on local epidemiological data. This study provides valuable data on common causative pathogens in DFU infections, as well as the resistance patterns of these pathogens, forming a baseline on which to base future DFU treatment plans.

Copper(II) salts and complexes of 2-amino-5-nitropyridine*

Four new copper compounds of 2-amino-5-nitropyridine/pyridinium (5NAP/5NAPH) have been prepared and characterized: (5NAPH)2[CuBr4], 2; (d2-5NAPD)2[CuBr4], 2a; (5NAP)2CuCl2, 3; (5NAP)2CuBr2, 4. Compounds 2 and 2a are isomorphous and crystallize in the triclinic space group P-1. Packing is stabilized by hydrogen/deuterium bonds. Short Br…Br contacts provide potential magnetic superexchange pathways, but only very weak antiferromagnetic exchange is observed (J/kB∼-2 K). Compounds 3 and 4 are also isomorphous and crystallize in the monoclinic space group P21/c. The molecules are linked into chains by bihalide bridges, and the chains linked into rectangular/square layers by short X…X. contacts. Variable temperature magnetic data were best fit by the S = ½ antiferromagnetic rectangular model for 3 (C = 0.429(1) emu-K/mol-Oe, J/kB = −9.38(6) K, J’/kB = −5.91(4) K). Variable temperature magnetic susceptibility data for 4 were best fit by the two-dimensional antiferromagnetic square lattice model (C = 0.43(1) emu-K/mol-Oe, J/kB = −36.5(2) K).

Holocene vegetation and wildfire disturbance in boreal central Yukon, Canada

Sediment cores were collected from Wrong (WL) and Lenore (LL) lakes in boreal central Yukon Territory, Canada, spanning circa 6000 years. Analyses of pollen, charcoal, magnetic susceptibility, levoglucosan, and down-scaled paleoclimatic data reveal the vegetation history and character/drivers of Holocene fire disturbance. Boreal forest has persisted in the region for millennia, with a regional mid-Holocene expansion of Picea mariana followed by expansion of Pinus contorta in the latest Holocene. The shortest reconstructed fire return intervals (FRI; ca. 110-125 years) occurred in the mid-Holocene, coincident with the development of highly flammable Picea-dominated forest and warm, dry summers that were characterized by elevated JJA Z500 anomalies and associated with an eastward/intense Aleutian Low. In the late-Holocene, FRI increased to ca. 240 years at WL and 280 years LL. Drivers of this change include regional cooling and increased precipitation, with a westward/weaker Aleutian Low position delivering more moisture to interior Yukon. Longer FRIs allowed for greater fuel accumulation between fires, enhancing fire size/severity. While higher fire frequency is noted in the mid-Holocene and increased fire size/severity in the late-Holocene, recent changes in Yukon fire disturbance suggest that the fire regime may soon lie outside the natural range of mid- and late-Holocene variability.

Monitoring the susceptibility of Bemisia tabaci Middle East-Asia Minor 1 (Hemiptera: Aleyrodidae) to afidopyropen, cyantraniliprole, dinotefuran, and flupyradifurone in south Florida vegetable fields.

Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) is a significant pest that damages a wide range of high-value vegetable crops in south Florida. This pest has demonstrated the ability to develop resistance to various insecticide groups worldwide. Monitoring the resistance levels of MEAM1 populations and maintaining baseline susceptibility data are crucial for the long-term effectiveness of insecticide management strategies. We conducted serial dilution bioassays on 15 field populations of MEAM1 collected in south Florida to assess their resistance to 4 key insecticides: afidopyropen, cyantraniliprole, dinotefuran, and flupyradifurone. To quantify resistance levels, resistance ratios (RR) were generated by comparing the LC50 values of field populations to those of a known susceptible MEAM1 colony reared in the laboratory. Our findings reveal that all field-collected populations were susceptible to dinotefuran (RR 1-8) and flupyradifurone (RR 2-8). While over 80% of the populations tested were susceptible to afidopyropen (RR 1-9), 2 populations exhibited low (RR 38) and moderate resistance (RR 51), respectively. In contrast, most of the populations (57%) showed low to moderate resistance to cyantraniliprole (RR 21-78), and the remaining populations were susceptible (RR 3-10). The 2 populations with resistance to afidopyropen also exhibited moderate resistance to cyantraniliprole. Further research in this direction can aid in refining insecticide resistance management programs in Florida and other regions where B. tabaci MEAM1 is a major pest. Exploring the implications of these findings will be essential for insecticide use and integrated pest management strategies in south Florida.

Electric Susceptibility at Partial Coverage of a Circular One-Side Access Capacitive Sensor with Rigid Polyurethane Foams.

The capability of dielectric measurements was significantly increased with the development of capacitive one-side access physical sensors. Complete samples give no opportunity to study electric susceptibility at a partial coverage of the one-side access sensor's active area; therefore, partial samples are proposed. The electric susceptibility at the partial coverage of a circular one-side access sensor with cylinders and shells is investigated for polyurethane materials. The implementation of the relative partial susceptibility permitted us to transform the calculated susceptibility data to a common scale of 0.0-1.0 and to outline the main trends for PU materials. The partial susceptibility, relative partial susceptibility, and change rate of relative partial susceptibility exhibited dependence on the coverage coefficient of the sensor's active area. The overall character of the curves for the change rate of the relative partial susceptibility, characterised by slopes of lines and the ratio of the change rate in the centre and near the gap, corresponds with the character of the surface charge density distribution curves, calculated from mathematical models. The elaborated methods may be useful in the design and optimization of capacitive OSA sensors of other configurations of electrodes, independent of the particular technical solution.

Chiral Heterometallic Cu8Ln4 Complexes with Enantiopure Schiff Base Ligands: Synthesis, Structural, Spectroscopic and Magnetic Studies.

The enantiomerically pure Schiff base ligands H2L-S and H2L-R yield chiral heterometallic dodecanuclear complexes of the form [Cu8Ln4(OH)8(OMe)4(O2CBut)8(L-S or L-R)4(H2O)4] where LnIII=Gd (1S), Tb (2S), Dy (3S, 3R), Ho (4S, 4R), Er (5S) or Y (6S, 6R) and H2L=(S or R)-2-{[(1-hydroxypropan-2-yl)imino]methyl}-6-methoxyphenol. The complexes are isomorphous and crystallize in the non-centrosymmetric polar space group C2 in enantiomeric conformation. The chirality of the Schiff base ligands originates from the respective S- or R- enantiomer of 2-aminopropan-1-ol, is imparted to the complexes and to the crystals that belong to non-centrosymmetric space group. The chirality and enantiomeric conformation of all complexes are retained in dmso solutions as confirmed by Circular Dichroism spectra which consist of mirror images, expected for enantiomeric pairs. All complexes consist of four distorted cubane-like subunits [Cu2Ln2(μ3-OH)2(μ3-OMe)(μ3-OR)], which share the LnIII ions and result in a cyclic distorted tetragonal arrangement; each edge of the {LnIII 4} quadrilateral is occupied by two μ-OH- ions that further bridge to a CuII ion. Magnetic susceptibility measurements revealed ferromagnetic interactions for 3S with LnIII=Dy and antiferromagnetic interactions for all other complexes. AC susceptibility data of 3S under 1 kOe external dc field indicate slow magnetic relaxation phenomena below 2 K.

Creative usage of Vivli’s Antimicrobial Resistance Surveillance Open Data through the Re-Use Data Challenge

The escalation of infections caused by drug-resistant bacteria worldwide poses a formidable challenge to global health, necessitating innovative approaches to combat this issue. In 2022, Vivli launched the Antimicrobial Resistance (AMR) Register, a platform that consolidates antimicrobial susceptibility data from pharmaceutical industry surveillance programs. This register provides a freely available and fully searchable user-friendly repository to facilitate scientific understanding of resistance patterns and support development of innovative strategies to address AMR globally. To promote the register’s utility, raise AMR awareness and encourage further re-use of the available data, Wellcome funded the Vivli AMR Surveillance Open Data Re-Use Data Challenge in 2023. This data challenge successfully fostered diverse, impactful, and innovative solutions that leveraged the AMR Register data to contribute to resolving the AMR crisis. The outcomes of the initiative underscore the importance of access to open data in stimulating collaboration and innovation in the public health domain, particularly in combatting the growing threat of drug-resistant infections.