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1.
Urologia ; : 3915603241254717, 2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39058221

RESUMO

INTRODUCTION: Sexual dysfunction affects a couple's relationship and quality of life of the patient and the partner irrespective of age. In Lower urinary tract symptoms (LUTS) with benign prostatic hyperplasia (BPH), sexual dysfunction is highly prevalent. This study aims to evaluate prevalence of sexual dysfunction in patients having LUTS with BPH and effect of various treatment on it. MATERIALS AND METHODS: The study is hospital based prospective cross-sectional study. Total 106 patients were included in this study. Fifty-six patients underwent medical treatment and 50 patients underwent transurethral resection of prostate (TURP) according to lower urinary tract symptom score along with grades of prostate. We measured prevalence of lower urinary tract symptoms, erectile dysfunction (ED), ejaculatory dysfunction (EJD).We compared the pre and post treatment ED, EJD scores in both medical and TURP group. RESULT: In our study, 11 (10.4%) patients had very mild ED, 12 (11.3%) had mild ED, 54 (50.9%) had moderate ED and 23 (21.7%) had severe ED. In our study, 11 (10.4%) patients had very mild EJD, 7 (6.6%) had mild EJD, 28 (26.4%) had moderate EJD and 2 (1.9%) had severe EJD. In medical group, ED pre-treatment versus ED post treatment was statistically significant (p = 0.0046), treatment of LUTS improves ED. EJD pre-treatment versus EJD post treatment was not statistically significant (p = 0.8368), treatment of LUTS associated with deterioration of EJD. In TURP group association of ED pre-treatment versus ED post treatment was statistically significant (p = 0.0319). Post TURP patients shows improvement in ED Association of EJD pre-treatment versus EJD post-treatment was statistically significant (p = 0.03000). Post TURP EJD deteriorate. CONCLUSION: We concluded that the severity of sexual dysfunction correlates with severity of LUTS. Ejaculatory function deteriorates after treatment of TURP compared to medical.

2.
J Org Chem ; 89(13): 9223-9232, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38885175

RESUMO

Enantioselective C(sp3)-H activation has garnered significant attention in synthetic and computational chemistry. Chiral transient directing groups (TDGs) hold promise for enabling Pd(II)-catalyzed enantioselective C(sp3)-H functionalization. Despite the interest in this strategy, it presents a challenge because the stereogenic center on the chiral TDG is frequently distant from the C-H bond, leading to a mixture of functionalized products. Our computational study on Pd(II)-catalyzed enantioselective ß-C(sp3)-H arylation of aliphatic ketone with chiral amino acids provides a sustainable route to synthesizing complex chiral molecular scaffolds. The cooperative action of 2-pyridone derivatives and chiral amino acids is crucial in promoting the enantio-discriminating C-H activation, oxidative addition, and reductive elimination steps. Using 5-nitro-2-pyridone as the optimal external ligand demonstrates its ability to achieve the highest level of enantioselection. In contrast, the modeled 3,5-di((trifluoromethyl)sulfonyl)-2-pyridone ligand facilitates the most straightforward C-H activation. This study underscores the pivotal role of the alkyl substituent at the α-position of the amino acid (TDG) in altering enantioselectivity.

3.
J Phys Condens Matter ; 36(28)2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38574681

RESUMO

Previous studies on the generalized XY model have concentrated on the equilibrium phase diagram and the equilibrium nature of distinct phases under varying parameter conditions. We direct our attention towards examining the system's evolution towards equilibrium states across different parameter values, specifically by varying the relative strengths of ferromagnetic and nematic interactions. We study the kinetics of the system, using the temporal annihilation of defects at varying temperatures and its impact on the coarsening behavior of the system. For both pure polar and pure nematic systems, we observe temperature-dependent decay of the exponent, leading to a decelerated growth of domains within the system. At parameter values where both ferromagnetic and nematic interactions are simultaneously present, we show a phase diagram highlighting three low-temperature phases-polar, nematic, and coexistence-along- side a high-temperature disordered phase. Our study provides valuable insights into the complex interplay of interactions, offering a comprehensive understanding of the system's behavior during its evolution towards equilibrium.

4.
Indian J Otolaryngol Head Neck Surg ; 76(1): 1195-1198, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38440584

RESUMO

Brain abscess is a serious clinical condition caused by a localized collection of pus within the brain tissue. This typically occurs as a result of an infection that originates from a nearby area, such as an ear, sinus, or dental infection, or an infection in the bloodstream. Streptococcus and Staphylococcus species are the most common organisms implicated in brain abscesses. Apart from aerobic growth, cases of mixed infections of both aerobic and anaerobic organisms are also commonly reported in the literature. Herein we report a 23-year-old immunocompetent female with chronic otitis media who presented with cerebellar abscess where the aerobic growth was sterile and anaerobic culture revealed pure growth of dual anaerobes viz… Peptostreptococcus and Bacteroides thetaiotaomicron. This case highlights the importance of prompt diagnosis and management of polymicrobial anaerobic infection in cases of brain abscess.

5.
ACS Appl Mater Interfaces ; 16(13): 16003-16010, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38512299

RESUMO

Single-molecule localization microscopy (SMLM) emerges as a powerful approach for super-resolution imaging that provides unprecedented resolution at the nanometer length scale. However, the development of appropriate probes with specific photophysical traits and characteristics is crucial for this approach. This study demonstrates two different fluorescent carbon dots (CDs) derived from the same molecular precursor─one emitting in red and the other in green─as a SMLM-based super-resolution imaging probe for different applications with an average localization precision of 20 nm and a resolution of 60 nm. Both the CDs exhibit spontaneous blinking with high photon count and low duty cycle but with different blinking cycles. The red emissive CDs with a lower blinking cycle are ideal for quantitative analysis, whereas green emissive CDs with a higher blinking cycle are ideal for high-resolution imaging. We show that the difference in blinking features is linked to their chemical compositions, and the presence of much denser trap states in red emitting CDs is responsible for the reduction of its blinking cycle. This study shows that CDs can be designed as a potential probe for SMLM-based super-resolution imaging for diverse bioimaging applications.

6.
ACS Appl Mater Interfaces ; 15(47): 54397-54408, 2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-37965697

RESUMO

Stimuli-responsive emission color modulation in fluorescent metal-organic frameworks (MOFs) promises luminescence-ink-based security application, while task-specific functionality-engineered pores can aid fast-responsive, discriminative, and ultralow detection of harmful organo-aromatics in the aqueous phase. Considering practical applicability, a self-calibrated fluoro-switch between encrypted and decrypted states is best suited for antiforgery measures, whereas image-based monitoring of organo-toxins by repetitive and handy methods over multiple platforms endorses in-field sensory potential. Herein, we constructed a mixed-ligand based chemically stable and bilayered-pillar MOF from -NH2-hooked pyridyl linker and tricarboxylate ligand that embraces negatively charged [Cd3(µ2-OH)(COO)6] node and shows pore-space-partitioning by nitrogen-rich flanked organic struts. Owing to the presence of a self-calibrating triazolylamine moiety-grafted auxiliary linker, this anionic MOF delineates reversible and multicyclic fluoro-swapping between protonated-encrypted and deprotonated-decrypted domains in the alternative presence of acid and base. Such pH-triggered, site-specific luminescence variation is utilized to construct highly regenerative anticounterfeiting labels for vivid acronym encryption. The intense fluorescence signature of the material is further harnessed in extremely selective and quick responsive sensing of harmful feed additive roxarsone (ROX) and dichloran (DCNA) pesticide in highly recyclable fashion with significant quenching and nanomolar limits of detection (ROX: 52 ppb; DCNA: 26.8 ppb). Notably, the ultrasensitive fluoro-detection of both these organo-toxins is successfully demonstrated via a handy paper-strip method as well as on the vegetable surface for real-time monitoring. Comprehensive density functional theory studies validate the electron transfer mechanism through redistribution of molecular orbital energy levels by each of the targeted analytes in this electron-rich framework besides evidencing MOF-analyte supramolecular interactions.

7.
J Org Chem ; 88(21): 15256-15269, 2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37823605

RESUMO

Herein, we disclose a simple strategy for the C-H alkylation of electron-rich (hetero)arenes with alkyl bromides employing visible-light-mediated organo-photocatalytic SET processes. The generality of this method has been evidenced by the inclusion of a variety of alkyl radicals (α-alkyl-carbonyl, benzyl, cyanomethyl) as well as diverse biologically active electron-rich arenes and (hetero)arenes under mild conditions. The extent of alkylation with alkyl bromides was found to be controlled by introducing Zn(OAc)2 as a bromide scavenger, ensuring the blocking of potential bromo-arene byproduct formation under photoredox conditions. In addition, a sequential C-H alkylation strategy for selective bis-alkylation has also been developed via chronological incorporation of different alkyl radical precursors in one pot quite efficiently.

8.
Commun Biol ; 6(1): 1050, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37848705

RESUMO

Over the last decade, single-molecule localization microscopy (SMLM) has developed into a set of powerful techniques that have improved spatial resolution over diffraction-limited microscopy and demonstrated the ability to resolve biological features down to a few tens of nanometers. We introduce a single molecule-based scanning SMLM (scanSMLM) system that enables rapid volume imaging. Along with epi-illumination, the system employs a scanning-based 4f detection for volume imaging. The 4f system comprises a combination of an electrically-tunable lens and high NA detection objective lens. By rapidly changing the aperture (or equivalently the focus) of an electrically-tunable lens (ETL) in a 4f detection system, the selectivity of the axial object plane is achieved, for which the image forms in the image/detector plane. So, in principle, one can scan the object volume by just altering the aperture of ETL. Two schemes were adopted to carry out volume imaging: cyclic scan and conventional scan. The cyclic scheme scans the volume in each scan cycle, whereas plane-wise scanning is performed in the conventional scheme. Hence, the cyclic scan ensures uniform dwell time on each frame during data collection, thereby evenly distributing photobleaching throughout the cell volume. With a minimal change in the system hardware (requiring the addition of an ETL lens and related electronics for step-voltage generation) in the existing SMLM system, volume scanning (along the z-axis) can be achieved. To calibrate and derive critical system parameters, we imaged fluorescent beads embedded in a gel-matrix 3D block as a test sample. Subsequently, scanSMLM is employed to visualize the architecture of actin-filaments and the distribution of Meos-Tom20 molecules on the mitochondrial membrane. The technique is further exploited to understand the clustering of Hemagglutinin (HA) protein single molecules in a transfected cell for studying Influenza-A disease progression. The system, for the first time, enabled 3D visualization of HA distribution that revealed HA cluster formation spanning the entire cell volume, post 24 hrs of transfection. Critical biophysical parameters related to HA clusters (density, the number of HA molecules per cluster, axial span, fraction of clustered molecules, and others) are also determined, giving an unprecedented insight into Influenza-A disease progression at the single-molecule level.


Assuntos
Influenza Humana , Cristalino , Humanos , Microscopia , Imagem Individual de Molécula/métodos , Progressão da Doença
9.
Phys Rev E ; 108(3-1): 034608, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37849122

RESUMO

We studied a system of polar self-propelled particles (SPPs) on a thin rectangular channel designed into three regions of order-disorder-order. The division of the three regions is made on the basis of the noise SPPs experience in the respective regions. The noise in the two wide regions is chosen lower than the critical noise of order-disorder transition and noise in the middle region or interface is higher than the critical noise. This makes the geometry of the system analogous to the Josephson junction (JJ) in solid-state physics. Keeping all other parameters fixed, we study the properties of the moving SPPs in the bulk as well as along the interface for different widths of the junction. On increasing interface width, the system shows an order-to-disorder transition from coherent moving SPPs in the whole system to the interrupted current for large interface width. Surprisingly, inside the interface, we observed the current reversal for intermediate widths of the interface. Such current reversal is due to the strong randomness present inside the interface, which makes the wall of the interface reflecting. Hence, our study gives new interesting collective properties of SPPs at the interface which can be useful to design switching devices using active agents.

10.
Appl Opt ; 62(14): 3703-3709, 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37706988

RESUMO

We demonstrate the linear and nonlinear characterization of a plasma-enhanced chemical vapor deposited silicon-rich silicon nitride (SRSN) racetrack ring resonator for on-chip applications within the telecommunication wavelength range. The SRSN waveguide parameters are optimized by employing the refractive index profile measured by ellipsometry to achieve flat dispersion in the telecom band. Furthermore, we measure the thermo-optic coefficient of the micro-resonator by analyzing the temperature-dependent transmission spectra and assess it to be 3.2825×10-5 ∘ C -1. Additionally, we study power-dependent transmission spectra to investigate the effect of local heating and nonlinear absorption. The power-dependent transmission spectra exhibit a blueshifting of the resonance peak in the visible and near-IR regions, which indicates the presence of nonlinear losses in that range. The power-dependent transmission spectra almost remain unchanged in the telecom band, revealing the absence of nonlinear losses and excellent thermal stability in that wavelength range. Our experimental results reveal that the SRSN-based structure can be employed potentially to realize linear and nonlinear applications in the telecom band.

11.
Sci Rep ; 13(1): 12561, 2023 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-37532749

RESUMO

The blinking properties of a single molecule are critical for single-molecule localization microscopy (SMLM). Typically, SMLM techniques involve recording several frames of diffraction-limited bright spots of single-molecules with a detector exposure time close to the blinking period. This sets a limit on the temporal resolution of SMLM to a few tens of milliseconds. Realizing that a substantial fraction of single molecules emit photons for time scales much shorter than the average blinking period, we propose accelerating data collection to capture these fast emitters. Here, we put forward a short exposure-based SMLM (shortSMLM) method powered by sCMOS detector for understanding dynamical events (both at single molecule and ensemble level). The technique is demonstrated on an Influenza-A disease model, where NIH3T3 cells (both fixed and live cells) were transfected by Dendra2-HA plasmid DNA. Analysis shows a 2.76-fold improvement in the temporal resolution that comes with a sacrifice in spatial resolution, and a particle resolution shift PAR-shift (in terms of localization precision) of [Formula: see text] 11.82  nm compared to standard SMLM. We visualized dynamic HA cluster formation in transfected cells post 24 h of DNA transfection. It is noted that a reduction in spatial resolution does not substantially alter cluster characteristics (cluster density, [Formula: see text] molecules/cluster, cluster spread, etc.) and, indeed, preserves critical features. Moreover, the time-lapse imaging reveals the dynamic formation and migration of Hemagglutinin (HA) clusters in a live cell. This suggests that [Formula: see text] using a synchronized high QE sCMOS detector (operated at short exposure times) is excellent for studying temporal dynamics in cellular system.


Assuntos
Hemaglutininas , Imagem Individual de Molécula , Animais , Camundongos , Células NIH 3T3 , Imagem Individual de Molécula/métodos , DNA
12.
Dalton Trans ; 52(25): 8661-8669, 2023 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-37306067

RESUMO

Concerning environmentally benign catalysis with reduced chemical usage, less energy consumption, and waste minimization, metal-organic frameworks (MOFs) with spatially isolated task-specific functionalities not only execute atom-economic important reactions but also enable size-exclusive catalysis at the interface of structure-function synergy. Herein, we synthesized a bipillar-layer Co(II) MOF from the dicarboxylate ligand and carboxamide moiety grafted pyridyl linker. The framework contains a [Co2(COO)4N4] secondary building unit (SBU) and shows excellent hydrolytic stability due to ample non-covalent interactions among the highly conjugated aromatic struts. Notably, the carboxamide functionalities remain free and are perfectly positioned throughout the one-dimensional channels of the framework, wherein three-fold interpenetration of the structure largely increases their density along the pore wall. Benefiting from these structural features, the activated MOF acts as an unprecedented organocatalyst in tandem deacetalization-Knoevenagel condensation towards electronically assorted substrates that were additionally characterized using single-crystal X-ray diffraction. Importantly, the reaction occurs under solvent-free mild conditions, and high catalyst reusability is recorded. In this one-pot cascade reaction, substrates with molecular dimensions larger than that of the three-fold interpenetration generated optimized pore-aperture undergo insignificant conversion, and therefore a rare molecular-dimension-induced size-selectivity is demonstrated. The catalytic route is detailed based on a battery of control experiments, including juxtaposing the performance of an isostructural MOF without any linker functionalization. Compared to the common Lewis acid mediated route, the results explicitly corroborate the first-ever substrate activation via hydrogen bonding to prepare coumarin derivatives via a tandem pathway, and shed light on this futuristic unconventional catalysis using contemporary materials and avoiding major operative glitches.

13.
ACS Appl Mater Interfaces ; 15(20): 24504-24516, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37162125

RESUMO

Development of the multifaceted metal-organic framework (MOF) with in situ engineered task-specific sites can promise proficient oxygen evolution reaction (OER) and high-temperature adsorption cum mild-condition fixation of CO2. In fact, effective assimilation of these attributes onto a single material with advance performance characteristics is practically imperative in view of renewable energy application and carbon-footprint reduction. Herein, we developed a three-fold interpenetrated robust Co(II) framework that embraces both redox-active and hydrogen-bond donor moieties inside the microporous channel. The activated MOF demonstrates notable OER catalysis in alkaline medium via quasi-reversible Co2+/Co3+ couple and unveils low overpotential with impressive 53.5 mV/dec Tafel slope that overpowers some benchmark, commercial, as well as contemporary materials. In particular, significantly increased turnover frequency (3.313 s-1 at 400 mV) and fairly low charge-transfer resistance (3.02 Ω) compared to Co3O4, NiO, and majority of redox-active MOFs together with 91% Faradaic efficiency and notable framework durability after multiple OER cycles endorse high-performance water oxidation. Pore-wall decked urea groups benefit appreciable CO2 adsorption even at elevated temperatures with considerable MOF-CO2 interactions and exhibit recurrent capture-release cycles at diverse temperatures. Interestingly, CO2 selectivity displays radical upsurge with temperature rise, affording 40% improved CO2/N2 value of 200 at 313 K, which outperforms many porous adsorbents and delineates real-time CO2 scavenging potential. The guest-free MOF effectively catalyzes solvent-free CO2 cycloaddition with broad substrate tolerance and satisfactory reusability under relatively mild condition. Opposed to the common Lewis acid-mediated reaction, two-point hydrogen-bonding activates the substrate, as supported from controlled experiments, juxtaposing the performance of an un-functionalized MOF and fluorescence modification-derived framework-epoxide interaction, providing valuable insights on unconventional cycloaddition route in the MOF.

14.
Bioresour Technol ; 370: 128523, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36565820

RESUMO

Machine Learning is quickly becoming an impending game changer for transforming big data thrust from the bioprocessing industry into actionable output. However, the complex data set from bioprocess, lagging cyber-integrated sensor system, and issues with storage scalability limit machine learning real-time application. Hence, it is imperative to know the state of technology to address prevailing issues. This review first gives an insight into the basic understanding of the machine learning domain and discusses its complexities for more comprehensive applications. Followed by an outline of how relevant machine learning models are for statistical and logical analysis of the enormous datasets generated to control bioprocess operations. Then this review critically discusses the current knowledge, its limitations, and future aspects in different subfields of the bioprocessing industry. Further, this review discusses the prospects of adopting a hybrid method to dovetail different modeling strategies, cyber-networking, and integrated sensors to develop new digital biotechnologies.


Assuntos
Biotecnologia , Aprendizado de Máquina
15.
Appl Opt ; 61(27): 7852-7860, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36255899

RESUMO

We demonstrate a detailed theoretical analysis describing the generation of an electro-optic comb (EOC) in the near-IR range through discrete phase and amplitude modulation driven by radio frequency (RF) signal generators. Furthermore, the generated EOC spectra suffer nonlinear spectral broadening while propagating through a hybrid Si-rich nitride (SRN) waveguide structure integrated with two-dimensional (2D) layered graphene oxide (GO) films. We perform a detailed analysis to investigate the influence of GO layers, pump wavelength detuning, and other waveguide parameters on the evolution of comb spectra propagating through the hybrid waveguide structure. Owing to the strong modal overlapping between the SRN waveguides and the highly nonlinear GO films, the nonlinearity of the system is enhanced effectively, and broadband comb spectra have been achieved in the near-IR range. Furthermore, we investigate the spectral coherence of the generated comb spectra under different input conditions. The results exhibit strong potential to generate a tunable frequency comb with high spectral coherence in the near-IR range by employing the hybrid waveguide structure.

16.
Rev Sci Instrum ; 93(9): 093704, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36182464

RESUMO

Molecules capable of emitting a large number of photons (also known as fortunate molecules) are crucial for achieving a resolution close to single molecule limit (the actual size of a single molecule). We propose a long-exposure single molecule localization microscopy (leSMLM) technique that enables detection of fortunate molecules, which is based on the fact that detecting a relatively small subset of molecules with large photon emission increases its localization precision (∼r0/N). Fortunate molecules have the ability to emit a large burst of photons over a prolonged time (> average blinking lifetime). So, a long exposure time allows the time window necessary to detect these elite molecules. The technique involves the detection of fortunate molecules to generate enough statistics for a quality reconstruction of the target protein distribution in a cellular system. Studies show a significant PArticle Resolution Shift (PAR-shift) of about 6 and 11 nm toward single-molecule-limit (far from diffraction-limit) for an exposure time window of 60 and 90 ms, respectively. In addition, a significant decrease in the fraction of fortunate molecules (single molecules with small localization precision) is observed. Specifically, 8.33% and 3.43% molecules are found to emit in 30-60  ms and >60 ms, respectively, when compared to single molecule localization microscopy (SMLM). The long exposure has enabled better visualization of the Dendra2HA molecular cluster, resolving sub-clusters within a large cluster. Thus, the proposed technique leSMLM facilitates a better study of cluster formation in fixed samples. Overall, leSMLM technique offers a spatial resolution improvement of ~ 10 nm compared to traditional SMLM at the cost of marginally poor temporal resolution.


Assuntos
Nanotecnologia , Imagem Individual de Molécula , Microscopia de Fluorescência/métodos , Imagem Individual de Molécula/métodos
17.
J Org Chem ; 87(14): 9222-9231, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35771188

RESUMO

The lack of directionality and the long-range nature of Coulomb interactions have been a bottleneck to achieve chemically precise C-H activation using ion-pairs. Recent report by Phipps and co-workers of the ion-pair-directed regioselective Iridium-catalyzed borylation opens a new direction toward harnessing noncovalent interactions for C-H activation. In this article, the mechanism and specific role of ion-pairing are investigated using density functional theory (DFT). Computational studies reveal that meta C-H activation is kinetically more favorable than the para analogue due to stronger electrostatic interactions between the ion-pairs in closer proximity [d(NMe3+···SO3-)TSP1m = 3.93 Å versus d(NMe3+···SO3-)TSP1p = 4.30 Å]. The electrostatic interactions overwhelm the Pauli repulsion and distortion interactions incurred in bringing the oppositely charged ions in close contact for the rate-limiting meta transition state (TSP1m). Multiple linear regression shows that the free energies of activation correlate well with descriptors like the charge densities on the meta carbon and Ir atom along with that on the cation and anion with R2 = 0.74. Tuned range-separated DFT calculations demonstrate accurately the localization of charge separation in the reactant complex and transition state for the meta selectivity.

18.
Sci Rep ; 12(1): 10229, 2022 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-35715431

RESUMO

Optical trapping and patterning cells or microscopic particles is fascinating. We developed a light sheet-based optical tweezer to trap dielectric particles and live HeLa cells. The technique requires the generation of a tightly focussed diffraction-limited light-sheet realized by a combination of cylindrical lens and high NA objective lens. The resultant field is a focussed line (along x-axis) perpendicular to the beam propagation direction (z-axis). This is unlike traditional optical tweezers that are fundamentally point-traps and can trap one particle at a time. Several spherical beads undergoing Brownian motion in the solution are trapped by the lightsheet gradient potential, and the time (to reach trap-centre) is estimated from the video captured at 230 frames/s. High-speed imaging of beads with increasing laser power shows a steady increase in trap stiffness with a maximum of 0.00118 pN/nm at 52.5 mW. This is order less than the traditional point-traps, and hence may be suitable for applications requiring delicate optical forces. On the brighter side, light sheet tweezer (LOT) can simultaneously trap multiple objects with the distinct ability to manipulate them in the transverse (xy) plane via translation and rotation. However, the trapped beads displayed free movement along the light-sheet axis (x-axis), exhibiting a single degree of freedom. Furthermore, the tweezer is used to trap and pattern live HeLa cells in various shapes and structures. Subsequently, the cells were cultured for a prolonged period of time (> 18 h), and cell viability was ascertained. We anticipate that LOT can be used to study constrained dynamics of microscopic particles and help understand the patterned cell growth that has implications in optical imaging, microscopy, and cell biology.


Assuntos
Lasers , Pinças Ópticas , Células HeLa , Humanos
19.
Sci Rep ; 12(1): 78, 2022 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-34997009

RESUMO

Optical imaging is paramount for disease diagnosis and to access its progression over time. The proposed optical flow imaging (VFC/iLIFE) is a powerful technique that adds new capabilities (3D volume visualization, organelle-level resolution, and multi-organelle screening) to the existing system. Unlike state-of-the-art point-illumination-based biomedical imaging techniques, the sheet-based VFC technique is capable of single-shot sectional visualization, high throughput interrogation, real-time parameter estimation, and instant volume reconstruction with organelle-level resolution of live specimens. The specimen flow system was realized on a multichannel (Y-type) microfluidic chip that enables visualization of organelle distribution in several cells in-parallel at a relatively high flow-rate (2000 nl/min). The calibration of VFC system requires the study of point emitters (fluorescent beads) at physiologically relevant flow-rates (500-2000 nl/min) for determining flow-induced optical aberration in the system point spread function (PSF). Subsequently, the recorded raw images and volumes were computationally deconvolved with flow-variant PSF to reconstruct the cell volume. High throughput investigation of the mitochondrial network in HeLa cancer cell was carried out at sub-cellular resolution in real-time and critical parameters (mitochondria count and size distribution, morphology, entropy, and cell strain statistics) were determined on-the-go. These parameters determine the physiological state of cells, and the changes over-time, revealing the metastatic progression of diseases. Overall, the developed VFC system enables real-time monitoring of sub-cellular organelle organization at a high-throughput with high-content capacity.


Assuntos
Citometria de Fluxo , Técnicas Analíticas Microfluídicas , Mitocôndrias/patologia , Tamanho Mitocondrial , Imagem Óptica , Células HeLa , Ensaios de Triagem em Larga Escala , Humanos , Processamento de Imagem Assistida por Computador , Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/instrumentação
20.
J Org Chem ; 86(10): 7069-7077, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-33979172

RESUMO

A Rh(III)-catalyzed regioselective redox-neutral cascade process of carbenoid functionalization followed by dephosphonylative annulation of benzoic acids with α-diazo-ß-keto phosphonate has been realized, which led to the direct synthesis of a privileged 3-substituted isocoumarin scaffold. To the best of our knowledge, this is the first report of a complete redox neutral method to synthesize isocoumarins using C-H functionalization strategy. In the catalytic cycle of this reaction, there are two possible pathways for the C-C coupling between ortho-positioned carbon atom of benzoic acid and the diazo carbon atom: (i) concerted 1,2-aryl shift and (ii) stepwise metal-carbene formation followed by migratory insertion. DFT study has predicted that the concerted pathway has lower activation energy as compared to the stepwise pathway by 1.5 kcal/mol.

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