bluuebunny/crossref_metadata_2025 huggingface dataset:
120 nm wide band tunable pulsed laser generation employing vanadium carbide MXene/polyvinyl alcohol (V2C-PVA) film
Authors: Ahmad Harith , Makhfuz Maryam Jasmine Mohd , Yusoff Norazriena , Albaqawi Hissah Saedoon
Published: November 2023

MXene, a group of 2D materials, has garnered significant attention from researchers due to its impressive characteristics, such as large surface area, high metallic conductivity, and strong nonlinear saturable absorption. These properties make MXene an excellent material for exploring new possibilities in ultrafast photonics technology. The present study has demonstrated that vanadium carbide (V2C) MXene can function as a saturable absorber (SA) and effectively generate Q-switching pulses in the 1.9 μm wavelength region. The molten salt synthesis method was used to synthesize V2C MXene, which involved the selective etching of aluminum (Al) layers from the V2AlC MAX Phase precursor. The V2C MXene was transformed into a thin film by mixing it with polyvinyl alcohol (PVA) using a solution casting technique. The resulting V2C-PVA film was found to have saturable absorption properties, with a modulation depth of 8% and saturation intensity of 1.6 MW cm −2. Upon integrating the V2C-PVA film into the Thulium/Holmium-doped fiber laser (THDFL) cavity, stable Q-switching pulses were realized at a central wavelength of 1896.9 nm with 13.9 nm of 3-dB spectral bandwidth. At the maximum pump power of 448.7 mW, the 2.2 μs of pulse duration, 58.26 kHz of repetition rate, and 31 nJ of pulse energy were achieved. By adjusting the tunable bandpass filter (TBPF) integrated within the THDFL cavity, the system has a tunable spectral range of approximately 120.75 nm, from 1889.75 nm to 2010.5 nm. The exceptional performance of V2C-based SA for Q-switching operation showcases the immense potential of other MXene materials in the future of photonics applications.
Raman reference database for organic molecules by using a Coupled-Optical Fiber Raman Spectrograph
Authors: Salinas-Luna Javier , Mentado-Morales Juan
Published: November 2023

In this work, an overview of a reference spectral database for diverse organic molecules often used in a chemistry laboratory is shown. Obtained typical Raman signals have been well-resolved within a range from 0 to 3250 cm−1 by using a Coupled-Optical Fiber Raman Spectrograph, COFRS, performing with a sample holder for liquids connected to optical fiber in its typical configuration and an excitation wavelength of 785 ηm. This optical device works by using some spectral acquisition parameters, as integration time, signal average, boxcar or signal smoothing, detector gain and laser variable output power. These last parameter was varied in each compound due to the different purity presented for each organic molecule, and so a higher Raman signal can be obtained. We have included some of the most typical organic molecules used. Further, the main idea is to show a Raman spectral collection for rapid molecular identification of the diverse functional groups related to organic molecules.
Light trajectories and thermal shadows casted by black holes in a cavity
Authors: Belhaj A. , Belmahi H. , Benali M. , Oualaid M. , Sedra M.B.
Published: November 2023

We explore the shadows and the photon rings casted by black holes in cavity. Placing the
observer inside such an isothermal background, we examine the influence of the cavity
temperature T
cav and the charge Q on the involved optical features. After
studying the effect of the horizon radius by varying Q, we investigate the thermal
behaviors of the black hole shadows in a cavity. For fixed charge values, we find that the
shadow radius r
s increases by decreasing T
cav. Varying such a temperature, we
discuss the associated energy emission rate. After that, we show that the curves in the r
s-T
cav plane share similarities with the G-T curves of the Anti de Sitter black
holes. Then, we study the trajectories of the light rays casted by black holes in a cavity.
We further observe that the light trajectory behaviors are different than the ones of the
non rotating black holes due to the cavity effect. Finally, we provide an evidence for the
existence of an universal ratio defined in terms of the photon sphere radius and the impact
parameter. Concretely, we obtain an optical ratio b
sp/r
sp∼√(3).
Symmetry-resolved entanglement in fermionic systems with dissipation
Authors: Murciano Sara , Calabrese Pasquale , Alba Vincenzo
Published: November 2023

We investigate symmetry-resolved entanglement in out-of-equilibrium fermionic systems subject to gain and loss dissipation, which preserves the block-diagonal structure of the reduced density matrix. We derive a hydrodynamic description of the dynamics of several entanglement-related quantities, such as the symmetry-resolved von Neumann entropy and the charge-imbalance-resolved fermionic negativity. We show that all these quantities admit a hydrodynamic description in terms of entangled quasiparticles. While the entropy is dominated by dissipative processes, the resolved negativity is sensitive to the presence of entangled quasiparticles, and it shows the typical ‘rise and fall’ dynamics. Our results hold in the weak-dissipative hydrodynamic limit of large intervals, long times and weak dissipation rates.
Statistical physics of learning in high-dimensional chaotic systems
Authors: Fournier Samantha J , Urbani Pierfrancesco
Published: November 2023

In many complex systems, elementary units live in a chaotic environment and need to adapt their strategies to perform a task by extracting information from the environment and controlling the feedback loop on it. One of the main examples of systems of this kind is provided by recurrent neural networks. In this case, recurrent connections between neurons drive chaotic behavior, and when learning takes place, the response of the system to a perturbation should also take into account its feedback on the dynamics of the network itself. In this work, we consider an abstract model of a high-dimensional chaotic system as a paradigmatic model and study its dynamics. We study the model under two particular settings: Hebbian driving and FORCE training. In the first case, we show that Hebbian driving can be used to tune the level of chaos in the dynamics, and this reproduces some results recently obtained in the study of more biologically realistic models of recurrent neural networks. In the latter case, we show that the dynamical system can be trained to reproduce simple periodic functions. To do this, we consider the FORCE algorithm—originally developed to train recurrent neural networks—and adapt it to our high-dimensional chaotic system. We show that this algorithm drives the dynamics close to an asymptotic attractor the larger the training time. All our results are valid in the thermodynamic limit due to an exact analysis of the dynamics through dynamical mean field theory.
Strategies for green industrial and innovation policy–an analysis of policy alignment, misalignment, and realignment around dominant designs in the EV sector
*
Authors: Narassimhan Easwaran , Myslikova Zdenka , Gallagher Kelly Sims
Published: November 2023

Governments in industrialized as well as emerging economies are racing to implement policies to accelerate clean energy innovation and capture the economic benefits of decarbonization. This paper explores which combination of technology-push and demand-pull policies best situates a country to lead in clean energy innovation, as new or dominant designs emerge and replace older technologies. A new analytical framework for green industrial policy is introduced regarding the alignment, misalignment, and deliberate misalignment of policies. This framework is applied to battery electric vehicle drivetrain technology to examine the use of policy alignment and misalignment by countries with big automakers as they pursue strategic green industrial policy. We find that countries that achieved early and sustained (not inconsistent) policy alignment gained a first-mover advantage compared with countries that deliberately or accidentally misaligned their policies. We also find that first-mover advantage can be lost due to deliberate misalignment of policies caused by an inability of governments to effectively incentivize their firms to develop and deploy cleaner and more efficient technologies. In situations where governments adopt misaligned or conflicting policies, incumbent industries tend to pursue their prior comparative advantage and maximize return from investments in prior technologies. We also find that deliberate misalignment of policies can be an effective catching-up strategy.
Investigation on the machinability of Biochar reinforced AA5083 Metal Matrix composites fabricated by stir casting technique
Authors: Praveen K , Raja R , Jannet Sabitha , George Lijin
Published: November 2023

Over the past two decades, there has been a significant rise in the demand for Aluminum Metal Matrix Composites (AAMCs) due to their notable advantages such as lightweight properties, increased strength, and enhanced hardness. In this study, three distinct AAMC samples based on Al5083 alloy, each varying in reinforcement levels at 4%, 8%, and 12% by weight were used. These composites were produced through a stir-casting process. The biochar used in our research was obtained through a pyrolysis process, adding an environmentally friendly and sustainable aspect to the composite materials. In the machining aspect of the study, A systematic L27 Taguchi Design of Experiment approach was used to investigate the influence of input parameters, namely cutting speed, feed rate, depth of cut, and weight percentage of reinforcement material, on the machining process. Further regression models were developed to gain insights into the relationships between these parameters and the resulting surface roughness. Turning operations at a cutting speed of 1050 rpm, a feed rate of 60 mm, and a depth of cut of 0.75 mm were idle for superior surface roughness and to assess the impact of the reinforcement material on the machined surface.
Anti-cancer and neuroprotective effects of conjugated graphene quantum dot in brain tumor-bearing rat model
Authors: Patel Vimal , Shah Jigar
Published: November 2023

Glioblastoma has been recognized as a most complex and highly malignant type of primary brain tumor. The rapid progression brain tumor model was developed by direct intracranial administration of ENU at the different focal brain points in the rat brains. The GQD was synthesized by bottom-up technique and functionalized with Trastuzumab and Caspase-8 antibody by Carbodiimide-amidation activation. The in-vitro cytotoxicity MTT assay was performed with all the GQD conjugates in SK-N-SH and N2a cell lines. The acute and chronic toxicity of synthesized GQD was performed in healthy rats and evaluated the hemolytic activity and CRP levels. A synthesized quasi-spherical 2D tiny GQD has a particle size of less than 10 nm and a 12.7% quantum yield. DSL, TEM, AFM, FTIR, and fluorescence spectroscopy characterized the GQD conjugates. In-silico molecular docking was a conformed static interaction between GQD and antibodies. GQD-conjugates showed dose-dependent toxicity in both cell lines and mild acute toxicity in rat blood. The GBM tumor-bearing rats were assessed for the anticancer and neuroprotective activity of the GQD conjugates. Histopathology, immunohistochemistry, metabolic, and inflammatory tumor biomarker estimation showed that the GQD_Caspase-8 conjugate showed better anti-tumor and neuroprotective effects than other conjugates.
A general-purpose organic gel computer that learns by itself
Authors: Sahoo Pathik , Singh Pushpendra , Saxena Komal , Ghosh Subrata , Singh R P , Benosman Ryad , Hill Jonathan P , Nakayama Tomonobu , Bandyopadhyay Anirban
Published: November 2023

To build energy minimized superstructures, self-assembling molecules explore astronomical options, colliding ∼109 molecules s−1. Thus far, no computer has used it fully to optimize choices and execute advanced computational theories only by synthesizing supramolecules. To realize it, first, we remotely re-wrote the problem in a language that supramolecular synthesis comprehends. Then, all-chemical neural network synthesizes one helical nanowire for one periodic event. These nanowires self-assemble into gel fibers mapping intricate relations between periodic events in any-data-type, the output is read instantly from optical hologram. Problem-wise, self-assembling layers or neural network depth is optimized to chemically simulate theories discovering invariants for learning. Subsequently, synthesis alone solves classification, feature learning problems instantly with single shot training. Reusable gel begins general-purpose computing that would chemically invent suitable models for problem-specific unsupervised learning. Irrespective of complexity, keeping fixed computing time and power, gel promises a toxic-hardware-free world.

One sentence summary: fractally coupled deep learning networks revisits Rosenblatt’s 1950s theorem on deep learning network.
Residential electricity demand on CAISO Flex Alert days: a case study of voluntary emergency demand response programs
Authors: Peplinski McKenna , Sanders Kelly T
Published: November 2023

The California Independent System Operator (CAISO) utilizes a system-wide, voluntary demand response (DR) tool, called the Flex Alert program, designed to reduce energy usage during peak hours, particularly on hot summer afternoons when surges in electricity demand threaten to exceed available generation resources. However, the few analyses on the efficacy of CAISO Flex Alerts have produced inconsistent results and do not investigate how participation varies across sectors, regions, population demographics, or time. Evaluating the efficacy of DR tools is difficult as there is no ground truth in terms of what demand would have been in the absence of the DR event. Thus, we first define two metrics that to evaluate how responsive customers were to Flex Alerts, including the Flex Period Response, which estimates how much demand was shifted away from the Flex Alert period, and the Ramping Response, which estimates changes in demand during the first hour of the Flex Alert period. We then analyze the hourly load response of the residential sector, based on ∼200 000 unique homes, on 17 Flex Alert days during the period spanning 2015–2020 across the Southern California Edison (SCE) utility’s territory and compare it to total SCE load. We find that the Flex Period Response varied across Flex Alert days for both the residential (−18% to +3%) and total SCE load (−7% to +4%) and is more dependent on but less correlated with temperature for the residential load than total SCE load. We also find that responsiveness varied across subpopulations (e.g. high-income, high-demand customers are more responsive) and census tracts, implying that some households have more load flexibility during Flex Alerts than others. The variability in customer engagement suggests that customer participation in this type of program is not reliable, particularly on extreme heat days, highlighting a shortcoming in unincentivized, voluntary DR programs.
‘Neighborhood residents cannot afford homeownership’: the limitations of community development on Latino enclaves
Authors: Rojas Reinaldo
Published: November 2023

The challenges of low-income neighborhoods and the different approaches to community economic development continue to dominate urban revitalization and poverty discussions. The ongoing, contested debate remains whether the nature of top-down business-oriented community economic development models serve the broader interests of the community residents or the narrow interests of its proponents and benefactors. This case study analyzes the impact of urban revitalization projects in Frog Hollow, an impoverished, but vibrant Latino enclave in Hartford, CT, and examines the limitations of top-down community economic revitalization and development strategies. The study also contributes to the community development literature by focusing on the Latino communities in the United States. This neighborhood underwent a highly publicized series of revitalization projects during the decade of the 2000s, which included business owners, community organizations, and local government in its development and implementation phases. This study focuses on three areas: identifying the history, goals, strategies, and tactics behind the community economic development model used in this urban revitalization project; examining the impact of the revitalization project on the socioeconomic conditions of the neighborhood and its residents; and determining how being an impoverished Puerto Rican/Latino enclave impacted the design, process, and implementation of the community development project.
Bioanalytical Method Development and Validation of Doxorubicin and Lapatinib in Rat Plasma Using UHPLC-HESI-LTQ-MS
Authors: Moinuddin Shaik Khaja , Srikanth Pirangi , Sharma Parul , Nandi Sukhendu
Published: November 2023

Cancer is considered a silent killer. The complexity of cancer makes it earn that title. So far there are only a few approaches to treat cancer. Among them, chemotherapy is considered the best approach. Many chemotherapeutical compounds are commercially available in the market. Among them, doxorubicin (DOX) and lapatinib (LAP) are considered blockbuster molecules. However, DOX suffers from poor bioavailability and exhibits cardiotoxicity. Interestingly, a fixed dose combination of DOX and LAP significantly decreases the cardiotoxic effect of DOX. To enhance the oral bioavailability of DOX and to avail the synergistic effect of LAP, many formulations have been made. To quantify both compounds in any formulation or biological matrix, an Liquid chromatography-Mass Spectrometry (LC-MS) method is required. In this present study, a simple and rapid Ultra High-Performance Liquid Chromatography - Heated Electron Spray Ionization - Mass Spectrometry (UHPLC-HESI-MS) bioanalytical method was developed. The developed method was validated as per the regulatory guidelines. The validated bioanalytical method had a lower limit of quantification of 0.75 ng. A simple protein precipitation technique was optimized to extract the compounds from the rat plasma. All the validation parameters were found to be within the limits as per the regulatory guidelines. A novel and rapid analytical method was successfully developed and validated. This developed method can be used to quantify the DOX and LAP in any formulation and biological matrix.
aSynPEP-DB: a database of biogenic peptides for inhibiting α-synuclein aggregation
Authors: Pintado-Grima Carlos , Bárcenas Oriol , Iglesias Valentín , Santos Jaime , Manglano-Artuñedo Zoe , Pallarès Irantzu , Burdukiewicz Michał , Ventura Salvador
Published: November 2023

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disorder, yet effective treatments able to stop or delay disease progression remain elusive. The aggregation of a presynaptic protein, α-synuclein (aSyn), is the primary neurological hallmark of PD and, thus, a promising target for therapeutic intervention. However, the lack of consensus on the molecular properties required to specifically bind the toxic species formed during aSyn aggregation has hindered the development of therapeutic molecules. Recently, we defined and experimentally validated a peptide architecture that demonstrated high affinity and selectivity in binding to aSyn toxic oligomers and fibrils, effectively preventing aSyn pathogenic aggregation. Human peptides with such properties may have neuroprotective activities and hold a huge therapeutic interest. Driven by this idea, here, we developed a discriminative algorithm for the screening of human endogenous neuropeptides, antimicrobial peptides and diet-derived bioactive peptides with the potential to inhibit aSyn aggregation. We identified over 100 unique biogenic peptide candidates and ensembled a comprehensive database (aSynPEP-DB) that collects their physicochemical features, source datasets and additional therapeutic-relevant information, including their sites of expression and associated pathways. Besides, we provide access to the discriminative algorithm to extend its application to the screening of artificial peptides or new peptide datasets. aSynPEP-DB is a unique repository of peptides with the potential to modulate aSyn aggregation, serving as a platform for the identification of previously unexplored therapeutic agents.

Database URL:  https://asynpepdb.ppmclab.com/
Long-term circatidal rhythms of heart rate, gill ventilation, and locomotion in the American horseshoe crab, Limulus polyphemus Linnaeus, 1758 (Arthropoda: Chelicerata: Merostomata: Limulidae)
Authors: Anderson Rebecca L , Watson Winsor H , Chabot Christopher C
Published: November 2023

While several marine species exhibit biological rhythms of heart rate, gill ventilation, or locomotion, the relationship between these three measures in any species remains unexplored. The American horseshoe crab, Limulus polyphemusLinnaeus, 1758, expresses circalunidian locomotor rhythms and circadian eye sensitivity rhythms, but it is not clear if either heart and ventilation rates are controlled on a circadian, or circatidal basis or the nature of the relationship between these three measures. We aimed to determine the extent to which the heart and ventilation rates of L. polyphemus are coordinated with its endogenous rhythms of locomotion. We recorded rhythmic beating of the heart and movements of the gill plates in freely moving horseshoe crabs. Most individuals exhibited robust circatidal rhythms of locomotion, heart rate, and ventilation that were highly correlated with each other over three weeks of continuous recording. These results are the first showing long-term rhythms of all three measures in any marine species and suggest that heart rate and ventilation rhythms are coordinated in L. polyphemus, both with each other, and with locomotion, and thus are all modulated on a tidal basis.
LPS and type I and II interferons have opposing effects on epigenetic regulation of LAIR1 expression in mouse and human macrophages
Authors: Dorando Hannah K , Mutic Evan C , Li Joanna Y , Perrin Ezri P , Wurtz Mellisa K , Quinn Chaz C , Payton Jacqueline E
Published: November 2023

Inhibitory immune receptors are important for maintaining immune homeostasis. We identified epigenetic alterations in 2 members of this group, LAIR1 and LAIR2, in lymphoma patients with inflammatory tissue damage and susceptibility to infection. We predicted that the expression of LAIR genes is controlled by immune mediators acting on transcriptional regulatory elements. Using flow cytometry, quantitative reverse-transcription polymerase chain reaction, and RNA sequencing, we measured LAIR1 and LAIR2 in human and murine immune cell subsets at baseline and posttreatment with immune mediators, including type I and II interferons, tumor necrosis factor α, and lipopolysaccharide (LPS). We identified candidate regulatory elements using epigenome profiling and measured their regulatory activity using luciferase reporters. LAIR1 expression substantially increases during monocyte differentiation to macrophages in both species. In contrast, murine and human macrophages exhibited opposite changes in LAIR1 in response to immune stimuli: human LAIR1 increased with LPS while mouse LAIR1 increased with interferon γ. LAIR genes had distinct patterns of enhancer activity with variable responses to immune stimuli. To identify relevant transcription factors (TFs), we developed integrative bioinformatic techniques applied to TF chromatin immunoprecipitation sequencing, RNA sequencing, and luciferase activity, revealing distinct sets of TFs for each LAIR gene. Most strikingly, LAIR1 TFs include nuclear factor kappa B factors RELA and RELB, while Lair1 and LAIR2 instead include STAT3 and/or STAT5. Regulation by nuclear factor kappa B factors may therefore explain the LPS-induced increase in LAIR1 expression, in contrast to Lair1 decrease. Our findings reveal new insights into transcriptional mechanisms that control distinct expression patterns of LAIR genes in response to inflammatory stimuli in human and murine myeloid and lymphoid cells.
93. Leveraging Stewardship to Promote Narrower-spectrum Antibiotic Use for Low-risk AmpC Enterobacterales
Authors: Hardy Megan E , Kenney Rachel M , Tibbetts Robert , Shallal Anita , Veve Michael
Published: November 2023

Background

AmpC β-lactamases are associated with development of ceftriaxone (CRO) resistance despite in vitro susceptibility, but the risk of AmpC derepression is not equal among Enterobacterales. The purpose of this study was to evaluate the impact of an AmpC stewardship intervention on definitive treatment of low-risk Enterobacterales.

Methods

IRB approved, single pre-test, post-test quasi-experiment with a non-equivalent dependent variable at a 5-hospital system. An AmpC stewardship intervention was implemented 7/22 and included education, removal of microbiology comments indicating potential for CRO resistance on therapy, and modification of a blood PCR comment for Serratia marcescens to recommend CRO. Inclusion: adults ≥ 18 years pre- (7/21-12/21) and post-intervention (7/22-12/22) who received ≥ 72 hours of inpatient definitive therapy and had non-urine cultures growing S. marcescens, Providencia spp., Citrobacter koseri, C. amalonaticus, C. farmeri, or Morganella morganii. Exclusion: infection with CRO resistant organisms. Primary outcome: proportion of patients who received definitive CRO therapy. Secondary outcomes at 30 days: retreatment for the same organism, development of CRO-resistant organisms, or Clostridioides difficile infection (CDI).

Results

224 patients were included: 115 (51%) pre- and 109 (49%) post-intervention. Table 1 describes patient, infection, and treatment characteristics. There were 79 (35%) patients with concurrent bacteremia. Definitive CRO therapy was prescribed more frequently after intervention 6 (5%) vs 72 (66%), P< 0.001. Median (IQR) total duration for pre- and post-groups (9 [7-17] vs 10 [7-18], P=0.46). After adjustment for intensive care, patients in the post-group were more likely to receive definitive CRO (adjOR, 35.4; 95%CI, 14.2-88.0) (Table 2). The proportion of patients who required retreatment was 18 (15%) and 11 (10%) for pre- and post-group patients (P=0.22). CRO resistance within 30 days occurred in 5 (4%) and 2 (2%) patients in the pre- and post-group (P=0.45).Table 1.Patient, infection, and treatment characteristicsTable 2.Variables associated with definitive CRO therapy

Conclusion

An antimicrobial stewardship intervention was associated with increased CRO prescribing and similar patient outcomes for low-risk AmpC Enterobacterales.

Disclosures

Michael Veve, PharmD, MPH, National Institutes of Health: Grant/Research Support|Paratek Pharmaceuticals: Grant/Research Support
977. Impact of Chlorhexidine (CHG) vaginal preparation compared to betadine on rates of Total abdominal Hysterectomy (TAH) Surgical Site Infections (SSI)
Authors: Neelakanta Anupama , Brown Jubilee , Handel Daniel , Fischer Kristin , Passaretti Catherine
Published: November 2023

Background

American College of Obstetricians and Gynecologists (ACOG) and the Centers for Disease Control (CDC) both recommend vaginal cleaning prior to surgery as part of hysterectomy SSI prevention. However, there is no clear guidance on preference of agent. Povidone-iodine is FDA approved for vaginal prep, but 4% chlorhexidine gluconate (CHG) is often used by surgeons as an acceptable alternative (off label) as there is some limited data to show improved bacterial counts with CHG.

Methods

In 2020, our healthcare system implemented a vaginal hysterectomy SSI bundle consisting of preoperative CHG bathing day of surgery, alcohol containing skin preparation, vaginal preparation with betadine, or CHG per surgeon preference and adherence to system guidelines on preoperative antibiotics. Additional bundle components for open procedures included use of a separate closing tray, re-gowning/re-gloving and re-draping prior to closing. The TAH Bundle was not mandatory but highly recommended. Compliance was monitored and feedback was given to key stakeholders monthly. In the third quarter 2022, the bundle was modified to make CHG the preferred agent for vaginal prep.

We performed a retrospective study of patients who underwent inpatient and outpatient TAH between 1/1/2020 to 12/31/2022 comparing rates of SSIs between patients who received CHG vs betadine for vaginal preparation.

Results

7327 TAH procedures were performed during the study period with rate of 1.24 TAH SSI per 100 procedures(Table 1). The rate of TAH SSI was 35% lower in the group receiving CHG vaginal prep compared to those who received betadine (IRR 0.65, p = 0.06). SSI rates and compliance with all components of the bundle varied by facility. The decrease associated with CHG vaginal prep compared to betadine was primarily in the group where all other bundle elements were followed (IRR 0.53, p=0.02) (Table 2).

Conclusion

In aggregate, use of CHG for vaginal prep was associated with a trend towards lower SSI. Use of CHG vaginal prep was associated with higher compliance with other bundle elements and facilities with higher compliance generally had lower SSI rates supporting bundle concept in SSI prevention. Limitations of this study include that individual patient level factors/case complexity, facility size were not taken into consideration.

Disclosures

All Authors: No reported disclosures
980. Risk Factors for Central Line Associated Bloodstream Infection Prior to and During the COVID-19 Pandemic
Authors: Priem Jennifer , Sampson Mindy , Kester Shelley , Bischoff Werner , Passaretti Catherine , Stephens Casey
Published: November 2023

Background

Central line associated bloodstream infections (CLABSIs) increased during the COVID-19 pandemic1-3, especially in patients infected with SARS-CoV-2,4 but there has been limited analysis on other risk factors associated with this increase.

Methods

We conducted a retrospective cohort study to assess risk factors for developing a CLABSI prior to (1/2019-3/2020) and during the COVID-19 pandemic (3/2020-2021) across 12 acute care hospitals in the Southeastern U.S. A multivariable logistic regression analysis was performed comparing patients with and without CLABSI.

Results

Of the 46,259 patients with central lines, 313 developed a CLABSI during the study period (109 pre- and 204 during- pandemic, a significant proportional increase.) Risk factors for CLABSI in the pre-pandemic period included cancer diagnosis, receipt of total peripheral nutrition (TPN) during hospital stay, Intensive Care Unit encounter, and longer length of stay and average line days (Table 1). During the pandemic, cancer diagnosis was no longer significantly associated with risk of CLABSI, but additional risk factors included Medicare insurance (OR 1.68), presence of a dialysis catheter (OR 1.57), COVID-19 diagnosis (OR 2.14), higher body mass index (OR 1.01) and Black race (OR 1.36). During the pandemic, we found that Black patients without COVID were 1.6 times (95% CI 1.09, 2.41) more likely to develop CLABSI compared to White patients (Table 2).

Conclusion

We detected a shift in risk factors for CLABSI during the pandemic. While COVID-19 diagnosis increased the risk of CLABSI, as has been shown in other studies4, our data additionally revealed a shift in risk factors in patients without COVID-19 showing a higher risk in those with black race, Medicare for insurance and presence of a dialysis catheter during the pandemic. These results suggest that alterations may have occurred in healthcare delivery, specifically in vulnerable populations, laying the foundation for future investigations into potential care improvements.

Disclosures

All Authors: No reported disclosures
1012. Protective Effects of Maternal Influenza Vaccine during Pregnancy and Breastfeeding on Risk of Infant Influenza
Authors: Rick Anne-Marie , D’Agostino Helen , Liu Hui , Williams John V , Balasubramani G K , Martin Judith M
Published: November 2023

Background

Children < 6 months of age are not eligible for influenza vaccine but are at high risk of influenza and its complications. Maternal influenza immunization (MII) in pregnancy or during lactation are two ways to provide infants vaccine specific influenza antibodies that could confer protection. Limited data delineate the individual and combined protective effects of MII and breastfeeding on influenza in infants. We aimed to evaluate the independent and combined protective effects of MII during pregnancy and breastfeeding against influenza during the first 6 months of life.

Methods

We utilized a retrospective cohort of mother-infant pairs, including infants born between January 1, 2012, to December 31, 2019 with longitudinal care within a single health system. Maternal influenza vaccine, breastfeeding and important covariates (Table 1) were obtained from electronic health records. We evaluated the odds of laboratory-confirmed influenza among infants < 6 months of age based on MII in pregnancy and breastfeeding status at 3 months of age using unadjusted and adjusted logistic regression following stepwise regression for covariates with p-value < 0.15.

Results

Of the 44,132 mother-infant pairs included, 0.3% (N=141) of infants had laboratory-confirmed influenza between birth and 6 months of age. 54% of infants received some/exclusive breastmilk at 3 months of age; 51% of mothers had MII during pregnancy. Breastfeeding alone (aOR: 0.77; 95%CI: 0.51-1.16) did not significantly protect against influenza compared to infants who received no breastmilk and no MII. In contrast, exposure to MII trended toward decreased risk of influenza by 37% (aOR: 0.63; 95%CI: 0.39-1.01), and the combination of MII in pregnancy and breastfeeding significantly decreased odds of infant influenza by 60% (aOR: 0.40; 95%CI: 0.25-0.66) (Table 1).

Conclusion

MII in pregnancy can effectively reduce the risk of influenza between 40-60% in children < 6 months. Breastfeeding significantly enhances that protection, either through its broad immune properties and/or the vaccine-specific antibodies in milk. Increasing the administration and acceptance of MII in pregnancy and improving sustained breastfeeding rates may help reduce the burden of infant influenza.

Disclosures

John V. Williams, MD, Merck: Grant/Research Support|Quidel: Board Member Judith M. Martin, MD, Merck, Sharp and Dhome: Grant/Research Support
1017. Impact of a Multifaceted Approach to Audit-and-Feedback Antimicrobial Stewardship Intervention in Acute Leukemia Patients Using Measures of Appropriateness
Authors: So Miranda , Alahmadi Ghadeer , Hamandi Bassem , Husain Shahid
Published: November 2023

Background

Prospective audit-and-feedback (PAF) for hospitalized leukemia patients is resource-intensive, while data on stadardized assessment of the quality, i.e. appropriateness, of antimicrobial prescribing are scarce. We implemented a multifaceted program combining patient-level PAF with unit-level appropriateness reports generated by serial point-prevalence surveys using the web-based Canadian National Antimicrobial Prescribing Survey (NAPSTM) platform. Quality of prescribing was assessed based on local guidelines and clinical justification using published definitions (Fig. 1). The objective of the study was to evaluate the impact of PAF+NAPS interventions on antibiotic use (AU) in acute leukemia patients at an academic cancer center, compared to PAF-only.

Methods

In this retrospective cohort study, during the PAF-only period (Jun 1 2017-May 31 2019), the AMS team led 30-minute PAF rounds with prescribers 2x/week. After implementating PAF+NAPS (Jun 1 2019-Mar 31 2020), we met 2x/month for 30 minutes. At each meeting we presented an automated NAPS dashboard report (Fig. 2) of aggregate appropriateness adjudication of antibiotic prescriptions, followed by targeted PAF on select patients with complex antimicrobial needs. We analyzed the impact of the two-step approach on the primary outcome of AU (defined daily dose [DDD]/100 patient-days [PD]) using interrupted time series models. Secondary outcomes were appropriateness of AU during PAF+NAPS, lenght of stay and in-hospital mortality. Target appropriatenesss was at least 90%. Categorical variables were compared using chi-square test and continuous variable using Mann Whitney U test.Fig. 2Sample Canadian NAPS Dashboard Report From a Point-Prevalence Survey

Results

Patient characteristics and outcomes were presented in Table 1. AU data were presented in Table 2. AU of piperacillin-tazobactam and vancomycin decreased significantly after implementation of 2x/month PAF+NAPS, compared to 2x/week PAF-only interventions (Fig. 3). Overall appropriateness was 91.4% (1757/1921 prescriptions).

Conclusion

Despite reducing frequency of interventions from 2x/week to 2x/month, PAF+NAPS was an efficient and sustainable AMS model that promoted appropriate and judicious antimicrobial use in hematology-oncology patients (Fig. 4), allowing the AMS team to expand to other specialized areas.

Disclosures

Shahid Husain, MD, Astellas: Grant/Research Support|Avir: Grant/Research Support|F2G: Grant/Research Support|Gilead: Grant/Research Support|Merck: Grant/Research Support|Pfizer: Grant/Research Support|Pulmocide: Grant/Research Support|Synexis: Grant/Research Support|Takeda: Honoraria
1106. Comparison of Diagnostic Power of Conventional Culture and Automated Blood Culture System with Pleural Fluid
Authors: Ho Lee Young , Kim Si-Ho , Yang Jinyoung , Ko Jae-Hoon , Young Cho Sun , Huh Heejae , Yong Lee Nam , Kang Cheol-In , Ryeon Chung Doo , Ran Peck Kyong , Huh Kyungmin
Published: November 2023

Background

Microbiological diagnosis of empyema is often hindered by low sensitivity of conventional culture. Automated blood culture system has been reported to enhance diagnostic power for culture of non-blood specimens. The purpose of this study is to compare the diagnostic power of conventional bacterial culture and automated blood culture system (ABCS) in patients who underwent thoracentesis or percutaneous drainage.

Methods

Non-duplicate patients whose pleural fluid was tested using both conventional culture and ABCS (BACT/ALERT 3D and VIRTUO, bioMerieux) from 1 Jan 2001 to 31 Dec 2021 were included. Cases in which coagulase-negative staphylococci were only positive isolates were excluded. Culture results, demographic information, and laboratory test results were obtained from the clinical data warehouse of Samsung Medical Center. The results from conventional cultures were compared against those from ABCS.

Results

A total of 9,020 patients who met the study criteria were identified. Among them, 819 patients had positive results other than coagulase-negative staphylococci from ABCS. Conventional culture was also positive in 360 (44.0%) patients, while 459 (56.0%) patients had isolates only from ABCS.

Pleural fluid from female and the patients with no pre-existing pleural drainage were significantly more likely to be culture positive by ABCS only (Table 1 and 2). In addition, pleural fluid LDH and serum CRP were significantly lower and pleural fluid glucose was significantly high in the patients with positive results from ABCS only. Among organisms isolated from both conventional culture and ABCS, the most frequently identified species was Staphylococcus aureus, followed by Klebsiella spp., and viridans group streptococci (Figure 1). Viridans group streptococci, Candida spp., and S. aureus were the most common species isolated from ABCS only (Figure 1).

Conclusion

More than a half of the patients whose pleural fluid culture were positive using ABCS had a negative conventional culture. Viridans group streptococci, Candida spp., and S. aureus were common species causing the discrepancy. Our results suggest that ABCS may enhance microbiologic diagnosis of empyema.

Disclosures

All Authors: No reported disclosures
1111. Lack of Effectiveness of Colistin in Carbapenem-Resistant Acinetobacter baumannii : A Retrospective Single Center Cohort Study
Authors: Kim Si-Ho , Jeon Cheon-Hoo , Mi Wi Yu
Published: November 2023

Background

Acinetobacter baumannii is a major pathogen for nosocomial infection. The emerging resistance of A. baumannii to carbapenem limits the appropriate antimicrobial agent options. Colistin has been used for the treatment of carbapenem-resistant A. buamannii (CRAB), but there were only a few studies evaluating effectiveness of colistin with appropriate controls. In this regard, we investigated the effectiveness of colistin in treating pneumonia caused by CRAB compared to CRAB pneumonia treated with no active drug.

Methods

Adult patients (≥ 18 years old) with CRAB isolated from their respiratory specimens were screened. Then, patients with pneumonia who were treated with colistin monotherapy (colistin group) as active antibiotics based on antimicrobial susceptibility and without any active antibiotics (no active drug group) were included. Pneumonia is defined as a new infiltrate on chest image and two of the following: 1) hyper or hypothermia (≥ 37.8 or ≤ 36.0 °C), 2) purulent respiratory secretion, 3) leukocytosis, and 4) hypoxemia. The primary outcome was 30 days of all-cause mortality. The secondary outcome was acute kidney injury within 30 days after pneumonia diagnosis or colistin administration. Only the patients who had baseline creatinine less than 2mg/dL were evaluated for the secondary outcome.

Results

Among 828 patients with CRAB in their respiratory specimens, 45 patients were treated with colistin, and 123 received no active antibiotics susceptible to CRAB. Most of the CRAB pneumonia was hospital-acquired pneumonia (91.1%), and 51.1% of patients were ventilator-associated pneumonia. Purulent respiratory secretion (100% vs. 87.8%, P=0.012) and use of carbapenems (71.1% vs. 48.8%, P=0.010) were more frequent in the colistin group. There was no difference in 28 days of all-cause mortality in colistin (41.7%) and no active drug group (43.9%) in raw (P=0.62) and adjusted analysis (adjusted HR 0.72, 95% CI 0.45-1.2). Incidence of acute kidney injury was numerically common in the colistin group (65.3% vs. 39.0% ) but no statistical significance was observed (P=0.143).

Survival curve since the onset of CARB pneumonia

Conclusion

Colistin might not have survival gain for the treatment of CRAB pneumonia. Newer effective antimicrobials effective for CRAB should be developed, evaluated, and rapidly applied to clinical practice.

Disclosures

All Authors: No reported disclosures
1929. Evaluating Disparities in Recurrent Clostridioides difficile Infection (CDI) and Fecal Microbiota Transplant (FMT) Treatment using Geospatial and Social Vulnerability Analytic Tools
Authors: Little Keighly , Mehta Nirja , Goodenough Dana , Dhonau Robin , Gupta Nitin , Woodworth Michael H , Fridkin Scott
Published: November 2023

Background

Recurrent CDI (rCDI) can be deadly and live biotherapies such as fecal microbiota transplantation (FMT) are now recommended at 2nd recurrence. Although incidence of Clostridioides difficile infection (CDI) historically is higher in white compared to black patients, the role of race or social determinates of health on rCDI is unclear. This study explores social determinants of risk for rCDI and treatment with FMT.

Methods

Georgia’s Emerging Infections Program (EIP) (supported by CDC) conducts CDI surveillance in 8 metropolitan Atlanta counties. Incident CDI (+toxin or molecular assay) in resident of catchment area (without previous + within 14 days) between 2016 and 2019 were categorized as single episode or rCDI ( >1 episode within 365 days) and geocoded (ArcGIS)-linked to CDC’s 2020 Social Vulnerability Index (SVI) data. Numerical values of each SVI variable (Table 1) were assigned to each patient. SVI theme and composite SVI were assessed as predictors for each rCDI and FMT receipt with most vulnerable defined categorically (top quartile) in log binomial logistic regression. Spatial analysis produced spot map of FMT, and choropleth maps of the CDI and rCDI rates per 100,000 persons.

Results

Among the 13,835 residents with CDI, 3,038 (22.0%) had rCDI and 250 (1.8%) had an FMT. Housing type and transportation was the only SVI predictor for rCDI while it was one of several SVI themes predictive of not receiving FMT (Table 2). Adjusting for age and sex, the most vulnerable patients in housing and transportation theme were 13% more likely to have recurrence (P-value<0.01) (Table 3). Independent predictors of FMT receipt included younger age and female sex. Importantly, patients living in a largely minority census tract were 37% less likely to receive an FMT and those in a largely uninsured tract 39% less likely (Table 3). Spatial analysis illustrates a strong discordance between FMT receipt and rCDI rates (Figure 1).

Conclusion

More socially vulnerable populations, defined by access to transportation and the level of household crowding, are more likely to develop rCDI. Likelihood of receiving FMT is substantially reduced among uninsured and persons of black race; both associations need consideration as novel live biotherapeutic products become available.

Disclosures

Nitin Gupta, MD, Abbvie: Advisor/Consultant|Amgen: Grant/Research Support|Bristol Myers Squibb: Advisor/Consultant|Bristol Myers Squibb: Grant/Research Support|Janssen: Advisor/Consultant|Janssen: Grant/Research Support|Pfizer/Arena: Advisor/Consultant|Pfizer/Arena: Grant/Research Support
1186. Beta is Better: Impact of a Multifaceted Stewardship Initiative on the Sequential Timing of Beta-Lactam Administration
Authors: Deri Connor R , Schultheis Jennifer , Shroba Jenny , Boreyko John , Wrenn Rebekah , Keener Cynthia , Moehring Rebekah W
Published: November 2023

Background

Appropriate antibiotic sequence (i.e. beta-lactam before vancomycin) may reduce early mortality in patients with bloodstream infections (BSIs). Herein, we describe the impact of a multifaceted stewardship initiative on the sequence of antibiotic administration across three hospitals.

Methods

We performed a pre-post analysis describing the impact of a multifaceted stewardship initiative from March 1, 2021 – May 22, 2022 (pre) and May 31, 2022 – Feb 12, 2023 (post) on the sequence of antibiotic administrations in adults > 18 years old with at least one positive blood culture who received vancomycin and a beta-lactam (i.e. cefepime, meropenem, or piperacillin-tazobactam) across three hospitals: a major university hospital and two community hospitals. Our initiative consisted of 1) a health-system wide adult beta-lactam order panel combining load and maintenance doses for select beta-lactams (Figure 1) 2) nursing administration instructions facilitating the appropriate sequential order of antibiotic administration (i.e. beta-lactam before vancomycin) (Figure 2) and 3) system-wide education to physicians, pharmacists, and nurses. The rate of beta-lactam first administration was compared between groups. Beta-lactam first rates were further stratified by hospital and antibiotic administration locations. Chi-square tests were used to compare rates between groups.

Beta-Lactam Order Panel, Piperacillin-tazobactam

Beta-Lactam First: Nursing Administration Instructions, Cefepime

Results

361 patients were included for analysis: 224 pre- and 137 post-intervention. Piperacillin-tazobactam was the most common beta-lactam among studied patients (71.5%, Table 1). Beta-lactam first rates were already high at baseline, then higher post-intervention compared to pre-intervention (96.4% vs 93.8%, p = 0.283) (Table 2).Table 1.Receipt of Beta-Lactam Therapy in Adult Patients with Positive Blood CulturesTable 2.Sequence of Antibiotic Administration

Conclusion

A multifaceted initiative to promote beta-lactam before vancomycin administration increased adherence to this preferred practice in our health system, though baseline rates were high. Clinical decision support paired with system-wide education involving key stakeholders can help standardize appropriate antibiotic sequence. Future study could evaluate impact on a larger scale, on patient outcomes, and evaluate sustainability of beta-lactam first practice.

Disclosures

Rebekah W. Moehring, MD, MPH, FIDSA, FSHEA, UpToDate, Inc.: Author Royalties