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1.
Phys Chem Chem Phys ; 25(35): 23645-23657, 2023 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-37609834

RESUMEN

The mechanism of intrinsic fluorescence of carbon dots (CDs), the latest nanomaterial from the carbon family, was supposedly deciphered through multiple theories. However, the much sought-after persistent red emission of CDs as a foreseeable consequence of experiments remains elusive prompting the question of whether tuning of the red emission of CDs is a predictable outcome or a serendipitous coincidence. Herein, we tried to decode the same by exploring Alizarin Red S (ARS)-based red emitting CDs in different solvents with wisely chosen analytical tools. The findings are aptly supported by molecular dynamics studies through an experimental intuition-driven model-building approach. Parallel interception of the CDs with powder X-ray diffraction (pXRD) and photophysical spectroscopic studies revealed an important relationship between the solvent and CDs. Tautomerism, a well-known phenomenon with chemical entities, was found to be operative for CDs that greatly influence the Stokes shift and ultimately the fluorescence outcome. Most importantly, pXRD studies established the turbostratism of the CDs where the well-ordered graphitic structure of CDs gets disrupted with solvent molecules. The extent of such disruption is a function of solvent and CD composition that plays a formidable role in obtaining red fluorescence. Thus, for the first time, we demonstrate that the red emission of CDs is related to its structural integrity and if taken care of could be sustained, a tremendously desirable outcome for relevant applications.

2.
Hum Factors ; 65(5): 779-791, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-33945351

RESUMEN

OBJECTIVE: The goal of this study is to model the effect of language use and time pressure on English as a first language (EFL) and English as a second language (ESL) students by measuring their eye movements in an on-screen, self-directed learning environment. BACKGROUND: Online learning is becoming integrated into learners' daily lives due to the flexibility in scheduling and location that it offers. However, in many cases, the online learners often have no interaction with one another or their instructors, making it difficult to determine how the learners are reading the materials and whether they are learning effectively. Furthermore, online learning may pose challenges to those who face language barriers or are under time pressure. METHOD: The effects of two factors, language use (EFL vs. ESL) and time constraints (high vs. low time pressure), were investigated during the presentation of online materials. The effects were analyzed based on eye movement measures (eye fixation rate-the total number of eye fixations divided by the task duration and gaze entropy) and behavioral measures (correct rate and task completion time). RESULTS: The results show that the ESL students had higher eye fixation rates and longer task completion times than the EFL students. Moreover, high time pressure resulted in high fixation rates, short task completion time, low correct rates, and high gaze entropy. CONCLUSION AND APPLICATION: The results suggest the possibility of using unobtrusive eye movement measures to develop ways to better assist those who struggle with learning in the online environment.


Asunto(s)
Educación a Distancia , Humanos , Tecnología de Seguimiento Ocular , Lenguaje , Aprendizaje , Barreras de Comunicación
3.
Phys Chem Chem Phys ; 24(15): 8578-8590, 2022 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-35355030

RESUMEN

A "one-pot one-step" synthesis method of Core/Alloy Shell (CAS) quantum dots (QDs) offers the scope of large scale synthesis in a less time consuming, more economical, highly reproducible and high-throughput manner in comparison to "multi-pot multi-step" synthesis for Core/Shell (CS) QDs. Rapid initial nucleation, and smooth & uniform shell growth lead to the formation of a compositionally-gradient alloyed hetero-structure with very significantly reduced interfacial trap density in CAS QDs. Thus, interfacial strain gets reduced in a much smoother manner leading to enhanced confinement for the photo-generated charge carriers in CAS QDs. Convincing proof of alloy-shelling for a CAS QD has been provided from HRTEM images at the single particle level. The band gap could be tuned as a function of composition, temperature, reactivity difference of precursors, etc. and a high PLQY and improved photochemical stability could be achieved for a small sized CAS QD. From the ultrafast exciton dynamics in CdSe and InP CAS QDs, it has been shown that (a) the hot exciton thermalization/relaxation happens in <500 fs, (b) hot electron trapping dynamics occurs within a ∼1 ps time scale, (c) band edge exciton trapping occurs within a 10-25 ps timescale and (d) for CdSe CAS QDs the hot hole gets trapped in about 35 ps. From fast PL decay dynamics, it has been shown that the amplitude of the intermediate time constant can be correlated with the PLQY. A model has been provided to understand these ultrafast to fast exciton dynamical processes. At the ultrasensitive single particle level, unlike CS QDs, CdSe CAS QDs have been shown to exhibit (a) constancy of PLmax (i.e. no bluing) and (b) constancy of PL intensity (i.e. no bleaching) of the single CAS QDs for continuous irradiation for one hour under an air atmosphere. Thus, CAS QDs hold the promise of being a superior optical probe in comparison to CS QDs both at the ensemble and at the single particle level, leading to enhanced flexibility of the CAS QDs towards designing and developing next generation application devices.

4.
Inorg Chem ; 58(3): 2042-2053, 2019 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-30633499

RESUMEN

The synthesis and characterization of a new pyrazine-based ditopic organoplatinum(II) complex having a bite angle of 180° is reported. The facile and efficient syntheses are described of three discrete neutral Fe(II)/Pt(II) heterobimetallic SCCs with Pt(II) acceptor clips of different binding angles, 0, 120, and 180°. These new SCCs were characterized by multinuclear NMR and mass spectrometry. Electrochemical response of these ferrocene containing self-assembled ensembles was studied using cyclic voltammetry. The diplatinum acceptor organometallic clips significantly quench the fluorescence of highly emitting carbon quantum dots (CD), while the self-assembled macrocycles tend to nullify the quenching effect of the organometallic clips. Interestingly, the inefficient quenching of CD fluorescence by these SCCs was found to be directly related to the angular disposition of the binding sites in the Pt(II) based organometallic clips.

5.
Bioconjug Chem ; 29(5): 1500-1504, 2018 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-29634254

RESUMEN

Controlled conjugation of fluorescent carbon dots (CDs) with DNA and subsequent fabrication of the CDs into an array through hybridization mediated self-assembly in the solution phase is reported. Covalent conjugation of CD with DNA and the subsequent array formation change the mobility of the CD-DNA array in gel electrophoresis and HPLC significantly. Interspatial distance in the CD-DNA array is tuned by the DNA sequence length and maintained at ∼8 ± 0.3 nm as revealed by electron microscopy studies. An increase in fluorescence lifetime by ∼2 ns was observed for the CD-DNA array compared to a solitary CD, vis-á-vis better imaging prospects of HEK293 cells by the former. Thus, the array displays improved fluorescence and unhindered cell penetration.


Asunto(s)
Carbono/química , ADN/química , Colorantes Fluorescentes/química , Análisis de Secuencia por Matrices de Oligonucleótidos , Imagen Óptica , Puntos Cuánticos/química , Fluorescencia , Células HEK293 , Humanos , Hibridación de Ácido Nucleico , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Imagen Óptica/métodos
6.
Phys Chem Chem Phys ; 20(15): 10332-10344, 2018 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-29610808

RESUMEN

CdSe-based core/gradient alloy shell/shell semiconductor quantum dots (CGASS QDs) have been shown to be optically quite superior compared to core-shell QDs. However, very little is known about CGASS QDs at the single particle level. Photoluminescence blinking dynamics of four differently emitting (blue (λem = 510), green (λem = 532), orange (λem = 591), and red (λem = 619)) single CGASS QDs having average sizes <∼7 nm have been probed in our home-built total internal reflection fluorescence (TIRF) microscope. All four samples possess an average ON-fraction of 0.70-0.85, which hints towards nearly suppressed PL blinking in these gradiently alloyed systems. Suppression of blinking has been so far achieved with QDs having sizes greater than 10 nm and mostly emitting in the red region (λem > 600 nm). In this manuscript, we report nearly suppressed PL blinking behaviour of CGASS QDs with average sizes <∼7 nm and emitting in the entire range of the visible spectrum, i.e. from blue to green to orange to red. The probability density distribution of both ON- and OFF-event durations for all of these CGASS QDs could be fitted well with a modified inverse truncated power law with an additional exponential model equation. It has been found that unlike most of the literature reports, the power law exponent for OFF-event durations is greater than the power law exponent for ON-event durations for all four samples. This suggests that relatively large ON-event durations are interrupted by comparatively small OFF-event durations. This in turn is indicative of a suppressed non-radiative Auger recombination process for these CGASS systems. However, in these four different samples the ON-event truncation time varies inversely with the OFF-event truncation time, which hints that both the ON- and OFF-event truncation processes are dictated by some common factor. We have employed 2D joint probability distribution analysis to probe the correlation between the event durations and found that residual memory exists in both the ON- and OFF-event durations. Positively correlated successive ON-ON and OFF-OFF event durations and negatively correlated (anti-correlated) ON-OFF event durations perhaps suggest the involvement of more than one type of trapping process within the blinking framework. The timescale corresponding to the additional exponential term has been assigned to hole trapping for ON-event duration statistics. Similarly, for OFF-event duration statistics, this component suggests hole detrapping. We found that the average duration of the exponential process for the ON-event durations is an order of magnitude higher than that of the OFF-event durations. This indicates that the holes are trapped for a significantly long time. When electron trapping is followed by such a hole trapping, long ON-event durations result. We have observed long ON-event durations, as high as 50 s. The competing charge tunnelling model has been used to account for the observed blinking behaviour in these CGASS QDs. Quite interestingly, the PLQY of all of these differently emitting QDs (an ensemble level property) could be correlated with the truncation time (a property at the single particle level). A respective concomitant increase-decrease of ON-OFF event truncation times with increasing PLQY is also indicative of a varying degree of suppression of the Auger recombination processes in these four different CGASS QDs.

8.
Artículo en Inglés | MEDLINE | ID: mdl-39284359

RESUMEN

Recently, the Kitaev-Heisenberg-$\Gamma$ system has been used to explore various aspects of Kitaev spin liquid physics. Here, we consider a few small clusters of up to twelve sites and study them in detail to unravel many interesting findings due to the competition between all possible signs and various magnitudes of these interactions under the influence of an external magnetic field. When Heisenberg interaction is taken anti-ferromagnetic, one obtains plateaus in correlation functions where, surprisingly, the exact groundstate reduces to the eigenstate of Heisenberg interaction as well. On the other hand, for ferromagnetic Heisenberg interaction, its competition with Kitaev interaction results in non-monotonicity in the correlation functions. We discuss, in detail, the competing effects on low energy spectrum, flux operator, magnetization, susceptibility, and specific heat. Finally, we discuss how our findings could be helpful to explain some of the recent experimental and theoretical findings in materials with Kitaev interactions.

9.
Ther Apher Dial ; 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39053908

RESUMEN

INTRODUCTION: Autoimmune neurological diseases (ANDs) involve the immune system attacking the nervous system, leading to various symptoms. Therapeutic plasma exchange (TPE) is used to remove pathogenic autoantibodies, aiming to improve clinical outcomes. METHODS: This ambispective observational study included 99 patients with ANDs who underwent TPE from January 2018 to June 2022 at a tertiary care center in India. Clinical outcomes were measured using the modified Rankin Scale (mRS) scores at admission, post-TPE, at 3-months, 6-months, and 1-year follow-up post-discharge. Data were analyzed using Epi Info version 7.0. RESULTS: The median mRS score improved significantly from 5 (IQR 4-5) before TPE to 3 (IQR 2-4) post-TPE (p < 0.001). Complications occurred in 5.95% of procedures, with allergic reactions being the most common. The in-hospital mortality rate was 9%. CONCLUSION: TPE is a safe and effective treatment modality for autoimmune neurological diseases, especially in resource-constrained settings. It aids in both symptomatic relief and reducing long-term functional disability.

10.
bioRxiv ; 2023 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-37961326

RESUMEN

Tetracycline (TET), a broad-spectrum antibiotic, also possesses different non-antibiotic activities such as inhibition of metalloproteinase (MMP), anti-inflammatory, antioxidant, high bone affinity, etc. However, the comparatively low efficacy of these non-antibiotic properties along with adverse effects such as hyperpigmentation, phototoxicity, long-term skeletal retention, etc. have not helped their broad utilization similar to their use as an antibiotic. In a unique attempt to improve the non-antibiotic properties while reducing the adverse effects, we converted the TET to nano-carbons through partial carbonization. After sorting out two water-dispersible C-TETs (C-TET HT - hydrothermal and C-TET HP - hot plate) based on their improved antioxidant activity, they have been characterized through a host of analytical techniques that showed distinct differences in morphology, size, shape, and surface functionality. Excitingly, the C-TET HT and C-TET HP have shown differential biological activity in a dosage and time-dependent manner in terms of cytotoxicity, immunomodulation, and osteogenic activity that was found to be associated with their carbonized parameters. Overall, the carbonized nano-drugs, C-TET HT and C-TET HP have presented substantial early promises on their non-antibiotic properties that could be further explored to develop into some effective therapeutics.

11.
Front Pediatr ; 11: 1292678, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38054187

RESUMEN

All national and international pediatric guidelines universally prescribe meticulous bilirubin screening for neonates as a critical measure to mitigate the incidence of acute bilirubin encephalopathy (ABE) and Kernicterus. The prevailing gold standard for jaundice detection in neonates necessitates invasive blood collection, followed by subsequent biochemical testing. While the invasive procedure provides dependable bilirubin measurements and continues to be the sole gold standard diagnostic method for assessing bilirubin concentration. There exists a pressing need to innovate non-invasive screening tools that alleviate the sampling stress endured by newborns, mitigate iatrogenic anemia, and expedite the turnaround time for obtaining results. The exploration of non-invasive modalities for bilirubin measurements is gaining momentum, driven by the overarching goal of minimizing the number of pricks inflicted upon neonates, thereby rendering screening a swift, efficient, comfortable, and dependable process. This comprehensive review article delves extensively into the array of non-invasive approaches and digital solutions that have been proposed, implemented, and utilized for neonatal bilirubin screening, with a particular emphasis on their application in low-resource settings. Within this context, the review sheds light on the existing methodologies and their practical applications, with a specific focus on transcutaneous bilirubin meters. Moreover, it underscores the prevailing open challenges in this domain and outlines potential directions for future research endeavors. Notably, the review underscores the imperative need for robust educational programs targeted at both families and healthcare personnel to expedite the process of seeking timely care for neonatal jaundice. Additionally, it underscores the necessity for the development of enhanced screening and diagnostic tools that can offer greater accuracy in clinical practice.

12.
Transfus Clin Biol ; 30(4): 449-453, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37689387

RESUMEN

INTRODUCTION: Defects in the lymphoid system have been linked to immune dysregulation, which might explain why lymphoid neoplasms and immunological disorders tend to occur concurrently. Chronic Lymphocytic Leukemia (CLL), characterised by the accumulation of dysfunctional lymphocytes, is associated with autoimmune cytopenias such as autoimmune haemolytic anaemia (AIHA). Detection of underlying alloantibody in warm AIHA, is challenging for any transfusion medicine specialist. This report highlights the significance of overflow phenomenon in detection of alloantibody in a case of warm AIHA secondary to CLL and myasthenia gravis. CASE REPORT: A 56-year-old male with a history of myasthenia gravis and thymoma progressed to B-cell CLL presented with severe anaemia and thrombocytopenia leading to multiple red blood cell (RBC) transfusions in the last two months. Clinical profile and laboratory workup suggested features of AIHA, and subsequent immunohaematological workup hinted towards an impending overflow phenomenon due to differential reactivity pattern observed between serum and eluate with antibody screen/identification panel. The eluate was pan-reactive with an antibody screen/ identification panel, while the serum showed a discrete anti-C alloantibody pattern. A compatible and antigen-negative RBC unit was successfully transfused, followed by medical management. DISCUSSION: The overflow phenomenon in AIHA depends on antibody titre and its affinity for RBC antigens. In the index case, the impending 'overflow or spillover' of autoantibodies into the patient's serum allowed us to detect underlying alloantibody without performing allogeneic adsorption and transfuse antigen-negative and crossmatch compatible PRBC unit. CONCLUSION: This case emphasises the significance of understanding the overflow phenomenon in AIHA as it can guide a transfusion medicine specialist in the early detection and identification of underlying alloantibodies, which is crucial for appropriate transfusion management in AIHA. However, early presentation and timely workup, along with a high level of suspicion, is crucial to identify this phenomenon.


Asunto(s)
Anemia Hemolítica Autoinmune , Leucemia Linfocítica Crónica de Células B , Miastenia Gravis , Trombocitopenia , Masculino , Humanos , Persona de Mediana Edad , Leucemia Linfocítica Crónica de Células B/complicaciones , Leucemia Linfocítica Crónica de Células B/diagnóstico , Leucemia Linfocítica Crónica de Células B/terapia , Isoanticuerpos , Eritrocitos , Anemia Hemolítica Autoinmune/complicaciones , Anemia Hemolítica Autoinmune/diagnóstico , Autoanticuerpos , Miastenia Gravis/complicaciones , Miastenia Gravis/diagnóstico , Trombocitopenia/complicaciones
13.
Regen Med ; 18(8): 601-610, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37491949

RESUMEN

Aim: This study aimed to assess the effect of platelet-rich plasma (PRP) on anterior cruciate ligament (ACL) graft healing at graft tunnel interface and ACL graft 6 months post-reconstruction. Material & methods: A randomized trial involving 87 patients was conducted, dividing them into PRP and non-PRP groups. Magnetic resonance imaging (MRI) and functional outcome measures were used to evaluate graft healing. Results: Out of the 87 patients, 80 were analyzed. The PRP group exhibited superior clinical and radiological outcomes compared with the non-PRP group, as indicated by Figueroas score, Lysholm score and knee range of motion. Conclusion: These findings demonstrate that PRP can be used as an adjunct therapy for ACL reconstruction, enhancing graft healing and improving patient outcomes. CTRI approval (Reg. No - CTRI/2018/11/016263).


This study investigated the effects of platelet-rich plasma (PRP) on the healing of the anterior cruciate ligament (ACL) after knee reconstruction surgery. The ACL is an important ligament for knee stability, and its tear is a common sports injury. PRP, a substance found in blood, has been used to speed up healing in various surgeries. In this study, 80 patients who underwent ACL reconstruction were randomly assigned to receive either PRP or standard treatment. After 6 months, the group treated with PRP showed improved healing and better knee function compared with the non-PRP group. These findings suggest that PRP can help accelerate ACL healing and improve outcomes for patients.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Reconstrucción del Ligamento Cruzado Anterior , Plasma Rico en Plaquetas , Humanos , Lesiones del Ligamento Cruzado Anterior/cirugía , Articulación de la Rodilla , Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior/métodos , Resultado del Tratamiento
14.
J Phys Chem Lett ; 14(1): 260-266, 2023 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-36595225

RESUMEN

Intrinsic hole trapping as well as hole detrapping have not been observed for any quantum dot (QD) or perovskite nanocrystal (PNC) system. Moreover, amplitude variation of intrinsic hole trapping (or detrapping) has not been reported at all for any QD or PNC system. However, for a CuInS2-based core/alloy-shell (CAS) QD system, (a) both intrinsic hole trapping and detrapping have been observed and (b) very significant amplitude variations of hole trapping (∼16 to ∼42%) and hole detrapping (∼44 to 23%) have been observed. Unlike detrimental electron trapping, hole trapping has been shown to be beneficial, having a direct correlation toward increasing PLQY to 96%. Simultaneous electron and hole trapping has been shown to be quite beneficial for the CuInS2-based CAS QD system leading to the longest ON time (∼130 s) for which a nontoxic metal-based QD remains only in the ON-state without blinking.

15.
Asian J Transfus Sci ; 17(2): 295-300, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38274951

RESUMEN

INTRODUCTION: Saw-scaled viper (Echis carinatus) belongs to the Viperidae family. Its venom is hemotoxic and contains several small peptides and proteins affecting the coagulation system. Commonly used anti-snake venom (ASV) products in India are reported to be ineffective or less effective in cases with bites by Echis carinatus sochureki which are commonly found in desert areas in Rajasthan. Although therapeutic plasma exchange (TPE) has been successful in patients with snakebite envenomation in the past, American Society for Apheresis guidelines 2019 included this indication under category III with grade 2C recommendation. AIM AND OBJECTIVES: To report the safety and efficacy of therapeutic plasma exchange procedures in the setting of ASV refractory E. c. sochureki envenomation. MATERIALS AND METHODS: Four patients admitted to our institute in 2021 September with an alleged history of snake bites and who underwent at least one cycle of therapeutic plasma exchange were assessed for clinical outcome, laboratory parameters, and blood product consumption. RESULTS: Three adult patients and one pediatric patient are included in this case series, all of them males. Indication for TPE in one case was suspected diffuse alveolar hemorrhage (DAH), while in all the other cases was thrombotic microangiopathy (TMA). All received a variable number of sessions from 2 to 5 and 1.3-1.5 plasma volume was removed on an average per cycle. The endpoint of TPE was the resolution of DAH in one while a reduction in lactate dehydrogenase and an increase in platelet count was in TMA cases. Consumption of blood products was drastically reduced in all four patients after starting the procedure. All the adult patients fared well on follow-up while the child had developed acute cortical necrosis and was dialysis-dependent. It has been noted in the previous studies too that a subset of snakebite-induced TMA cases was getting converted to chronic kidney disease and becoming dialysis dependent in the long run. CONCLUSIONS: In regions where ASV treatment failure is very common, therapeutic plasma exchange is a safe and effective complementary treatment modality along with supportive care.

16.
N Engl J Med ; 361(2): 161-9, 2009 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-19587341

RESUMEN

We present a case of disseminated histoplasmosis, complicated by retroperitoneal bleeding and leading to death, in a patient who was receiving systemic immunosuppressive therapy for rheumatoid arthritis and who was enrolled in a gene-therapy trial. This trial was designed to evaluate intraarticular delivery of a tumor necrosis factor alpha (TNF-alpha) antagonist, through an adeno-associated virus (AAV) type 2 delivery system, for inflammatory arthritis. The patient's receipt of concurrent anti-TNF-alpha therapy and other immunosuppressive therapy while she was living in an area where histoplasmosis was endemic was thought to be the most likely explanation for the infection; the evidence presented suggests that this fatal infection was unlikely to have been related to exposure to the agent administered in the gene-therapy trial. This case reinforces the importance of considering infectious complications, such as those from endemic mycoses, in patients receiving treatment with a TNF-alpha antagonist and the importance of having a well-designed monitoring plan when subjects in a research study become ill. (ClinicalTrials.gov number, NCT00126724.)


Asunto(s)
Artritis Reumatoide/terapia , Terapia Genética/efectos adversos , Hematoma/etiología , Histoplasmosis/etiología , Inmunosupresores/efectos adversos , Infecciones Oportunistas/etiología , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Adulto , Artritis Reumatoide/tratamiento farmacológico , Causas de Muerte , Dependovirus/genética , Resultado Fatal , Femenino , Vectores Genéticos , Hematoma/diagnóstico por imagen , Histoplasma/aislamiento & purificación , Humanos , Inmunosupresores/uso terapéutico , Hígado/microbiología , Hígado/patología , Radiografía , Espacio Retroperitoneal/diagnóstico por imagen , Trombocitopenia/etiología , Factor de Necrosis Tumoral alfa/genética
17.
J Phys Condens Matter ; 34(21)2022 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-35287116

RESUMEN

We study the revival of Hofstadter butterfly due to the competition between disorder and electronic interaction using mean field approximation of unrestricted Hartree Fock method at zero temperature for two dimensional square and honeycomb lattices. Interplay of disorder and electronic correlation to nullify each other is corroborated by the fact that honeycomb lattice needs more strength of electronic correlation owing to its less co-ordination number which enhances the effect of disorder. The extent of revival of the butterfly is better in square lattice than honeycomb lattice due to higher coordination number. The effect of disorder and interaction is also investigated to study entanglement entropy and entanglement spectrum. We find that for honeycomb lattice area law of entanglement entropy is obeyed in all cases but for square lattice there is some departure from area law for larger subsystems. The entanglement spectrum have the reflection symmetry of the original butterfly of the Hofstadter spectrum. The interaction induces a gap in the entanglement spectrum as well conforming the correspondence between physical spectrum and entanglement spectrum. The effect of disorder closes the interaction induced gap in the entanglement spectrum establishing the nullification of interaction due to disorder and vice versa.

18.
J Phys Chem Lett ; 13(10): 2404-2417, 2022 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-35257586

RESUMEN

The importance of alloy-shelling in optically robust Core/Alloy-Shell (CAS) QDs has been described from structural and energetic aspects. Unlike fluorescent dyes, both Core/Shell (CS) and CAS QDs exhibit excitation-energy-dependent photoluminescence quantum yield (PLQY). For both CdSe and InP CAS QDs (with metal- and nonmetal-based alloy-shelling, respectively), with increasing excitation energy, (a) the ultrafast rise-time or relaxation-time to the band-edge increases and (b) the magnitude of the normalized bleach signal decreases. Ultrasensitive single-particle spectroscopic investigation results showed that with decreasing excitation energy, (a) the fraction of ON events increases, (b) the ratio of exciton-detrapping rate/trapping rate increases, and (c) the extent of beneficial hole trapping increases. A relative decrease in PLQY with increasing excitation energy is much less pronounced in CAS QDs than in CS QDs. Unless trap states are removed completely especially in the higher-energy landscape, PLQY will remain inherently dependent on excitation energy for QDs in the vast energy landscape. When reporting the PLQY of QDs, the magnitude of the excitation energy must be mentioned.


Asunto(s)
Puntos Cuánticos , Aleaciones , Luminiscencia , Fenómenos Físicos , Puntos Cuánticos/química , Sulfuros/química
19.
Sci Rep ; 12(1): 16453, 2022 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-36180490

RESUMEN

We evaluated the anti-leishmanial efficacy of different saturated medium-chain fatty acids (FAs, C8-C18) where FA containing C8 chain, caprylic acid (CA), was found to be most potent against Leishmania donovani, the causative agent for visceral leishmaniasis (VL). Different analogs of CA with C8 linear chain, but not higher, along with a carboxyl/ester group showed a similar anti-leishmanial effect. Ergosterol depletion was the major cause of CA-mediated cell death. Molecular docking and molecular dynamic simulation studies indicated the enzyme mevalonate kinase (MevK) of the ergosterol biosynthesis pathway as a possible target of CA. Enzyme assays with purified recombinant MevK and CA/CA analogs confirmed the target with a competitive inhibition pattern. Using biochemical and biophysical studies; strong binding interaction between MevK and CA/CA analogs was established. Further, using parasites with overexpressed MevK and proteomics studies of CA-treated parasites the direct role of MevK as the target was validated. We established the mechanism of the antileishmanial effect of CA, a natural product, against VL where toxicity and drug resistance with current chemotherapeutics demand an alternative. This is the first report on the identification of an enzymatic target with kinetic parameters and mechanistic insights against any organism for a natural medium-chain FA.


Asunto(s)
Antiprotozoarios , Productos Biológicos , Leishmania donovani , Leishmaniasis Visceral , Antiprotozoarios/uso terapéutico , Productos Biológicos/farmacología , Caprilatos/farmacología , Ergosterol/metabolismo , Ésteres/farmacología , Ácidos Grasos/metabolismo , Humanos , Leishmaniasis Visceral/parasitología , Simulación del Acoplamiento Molecular , Fosfotransferasas (Aceptor de Grupo Alcohol)
20.
J Clin Apher ; 26(6): 362-5, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22038876

RESUMEN

Encephalitis associated with autoantibodies directed against the N-methyl-D-aspartate receptor (NMDAR) is usually a paraneoplastic syndrome that presents in young females with ovarian teratomas. We report a case of a previously healthy 14-year-old girl with sudden-onset paranoia, hallucinations, hyperactivity, increased speech, decreased sleep, seizures, and violent behavior deteriorating to catatonia. Her cerebrospinal fluid tested positive for anti-NMDAR antibodies. She was treated with five sessions of therapeutic plasma exchange (TPE) after having failed therapy with antibiotics, intravenous steroids, intravenous immunoglobulin (IVIG), one dose of rituximab, and seven sessions of electroconvulsive therapy (ECT). The American Society for Apheresis assigns a Category III (Grade 2C) recommendation for TPE in paraneoplastic neurologic syndromes; however, apheresis specifically for anti-NMDAR encephalitis has not been well studied. Literature review revealed two case reports describing outstanding improvement in patients with anti-NMDAR encephalitis following TPE. We report no improvement in our patient's symptoms after plasma exchange and discuss possible reasons for why it failed along with review of the literature.


Asunto(s)
Encefalitis Antirreceptor N-Metil-D-Aspartato/terapia , Intercambio Plasmático , Adolescente , Encefalitis Antirreceptor N-Metil-D-Aspartato/diagnóstico , Encefalitis Antirreceptor N-Metil-D-Aspartato/psicología , Catatonia/terapia , Terapia Combinada , Femenino , Humanos , Insuficiencia del Tratamiento
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