Publications by authors named "N Haldar"

Diaryl thieno-[3,4-]thiophenes (TT) are photoswitchable compounds that operate through reversible photoinduced cyclization/cycloreversion and have been designed specifically for integration within π-conjugated polymers to switchably manipulate polymer electronic properties. Here we report on how cross conjugating the central TT moiety impacts photocyclization dynamics as interrogated using transient absorption spectroscopy (TAS) for a series of switches built with electron-rich substituents that have various electronic interaction strengths with the TT core. For cross-conjugated structures exhibiting a propensity to switch in steady-state photoconversion experiments, ultrafast TAS reveals signatures of rapid dynamics (occurring within <1-10 ps) similar to those observed for unsubstituted switches and that are consistent with photocyclization.

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Glioblastoma is one of the most recurring types of glioma, having the highest mortality rate among all other gliomas. Traditionally, the standard course of treatment for glioblastoma involved maximum surgical resection, followed by chemotherapy and radiation therapy. Nanocarriers have recently focused on enhancing the chemotherapeutic administration to the brain to satisfy unmet therapeutic requirements for treating brain-related disorders.

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Article Synopsis
  • The study investigates the UV-induced photo-relaxation dynamics of 5-bromouracil (BrU) and 5-bromo-2'-deoxyuridine (BrUrd) using advanced femtosecond time-resolved photoelectron spectroscopy.
  • Upon UV excitation, both molecules quickly relax to lower electronic states before returning to the ground state, with an intermediate πσ* state identified in the process.
  • Unlike thymine, the study observes that neither the nπ* state nor a long-lived triplet state forms, with solvent effects limiting the dissociation yield in the solutions tested.
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With a prevalence of 12.5% of all new cancer cases annually, breast cancer stands as the most common form of cancer worldwide. The current therapies utilized for breast cancer are constrained and ineffective in addressing the condition.

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Time-resolved photoelectron spectroscopy using an extreme-ultraviolet (XUV) probe pulse was used to investigate the UV photoinduced dynamics of adenine (Ade), adenosine (Ado), and adenosine-5-monophosphate (AMP) in a liquid water jet. In contrast to previous studies using UV probe pulses, the XUV pulse at 21.7 eV can photoionize all excited states of a molecule, allowing for full relaxation pathways to be addressed after excitation at 4.

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