Photochemical Synthesis of Nonplanar Small Molecules with Ultrafast Nonradiative Decay for Highly Efficient Phototheranostics.

There has been much recent progress in the development of photothermal agents (PTAs) for biomedical and energy applications. Synthesis of organic PTAs typically involves noble metal catalysts and high temperatures. On the other hand, photochemical synthesis, as an alternative and green chemical technology, has obvious merits such as low cost, energy efficiency, and high yields. However, photochemical reactions have rarely been employed for the synthesis of PTAs. Herein, a facile and high-yield photochemical reaction is exploited for synthesizing nonplanar small molecules (NSMs) containing strong Michler's base donors and a tricyanoquinodimethane acceptor as high-performance PTAs. The synthesized NSMs show interesting photophysical properties including good absorption for photons of over 1000 nm wavelength, high near-infrared extinction coefficients, and excellent photothermal performance. Upon assembling the NSMs into nanoparticles (NSMN), they exhibit good biocompatibility, high photostability, and excellent photothermal conversion efficiency of 75%. Excited-state dynamic studies reveal that the NSMN has ultrafast nonradiative decay after photoexcitation. With these unique properties, the NSMN achieves efficient in vivo photoacoustic imaging and photothermal tumor ablation. This work demonstrates the superior potential of photochemical reactions for the synthesis of high-performance molecular PTAs.

Stimuli-Responsive Reversible Switching of Intersystem Crossing in Pure Organic Material for Smart Photodynamic Therapy.

Photosensitizers (PSs) with stimuli-responsive reversible switching of intersystem crossing (ISC) are highly promising for smart photodynamic therapy (PDT), but achieving this goal remains a tremendous challenge. This study introduces a strategy to obtain such reversible switching of ISC in a new class of PSs, which exhibit stimuli-initiated twisting of conjugated backbone. We present a multidisciplinary approach that includes femtosecond transient absorption spectroscopy and quantum chemical calculations. The organic structures reported show remarkably enhanced ISC efficiency (ΦISC ), switching from nearly 0 to 90 %, through an increase in the degree of twisting, providing an innovative mechanism to promote ISC. This leads us to propose here and demonstrate the concept of smart PDT, where pH-induced reversible twisting maximizes the ISC rate, and thus enables strong photodynamic action only under pathological stimulus (such as change in pH, hypoxia, or exposure to enzymes). The ISC process is turned off to deactivate PDT ability, when the PS is transferred or metabolized away from pathological region.

Improvement of balance in young adults by a sound component at 100 Hz in music.

About 80% of young people use personal listening devices (PLDs) including MP3 players to listen to music, which consists of sound components with various frequencies. Previous studies showed that exposure to noise of high intensities affected balance in humans. However, there is no information about a frequency-dependent effect of sound components in music from a PLD on balance in young people. In this study, we determined the associations between sound component levels (dB) at 100, 1000 and 4000 Hz in music from a portable listening device (PLD) and balance objectively determined by posturography in young adults (n = 110). We divided the subjects into two groups (low and high exposure groups) based on cut-off values of sound component levels at each frequency using receiver operating characteristic (ROC) curves. Balance in the high exposure group (≥46.6 dB) at 100 Hz was significantly better than that in low exposure group in logistic regression models adjusted for sex, BMI, smoking status and alcohol intake, while there were no significant associations at 1000 and 4000 Hz. Thus, this study demonstrated for the first time that the sound component at 100 Hz with more than 46.6 dB in music improved balance in young adults.

Regional, socioeconomic, and dietary factors influencing B-vitamins in human milk of urban Chinese lactating women at different lactation stages.

BACKGROUND: Adequate B-vitamins concentrations in human milk are considered to be a prerequisite for healthy development of infants in early life. This study aims to determine the concentrations of B-vitamins in human milk from Chinese women and the relationships between their concentrations and different geographical origin, lactation stages, socioeconomic characteristics, and dietary intake. METHODS: Human milk was obtained from 443 healthy lactating women from Beijing (n = 150), Suzhou (n = 146), and Guangzhou (n = 147) cities. Thiamine, riboflavin, vitamin B3 (nicotinamide and nicotinic acid), and vitamin B6 (pyridoxal, pyridoxine, and pyridoxamine) in human milk were analyzed by high performance liquid chromatography-tandem mass spectrometry. Pantothenic acid, biotin, and folates in human milk were analyzed by microbiological assay. The information from one 24-h dietary recall and socioeconomic characteristics were collected by interview and structured questionnaire, respectively. RESULTS: B-vitamins concentrations in human milk varied greatly among individuals. The median concentrations of B-vitamins of postpartum 5-11 d, 12-30 d, 31-60 d, 61-120 d, and 121-240 d were respectively as follows: thiamine 3.13, 5.07, 4.28, 5.65, 6.28 (µg/100 g); riboflavin 20.8, 20.2, 11.9, 13.6, 15.6 (µg/100 g); vitamin B3 194.0, 300.0, 261.0, 212.5, 218.0 (µg/100 g); pantothenic acid 236.5, 291.0, 254.0, 179.0, 189.0 (µg/100 g); vitamin B6 6.34, 7.58, 8.60, 9.34, 10.20 (µg/100 g); biotin 0.462, 0.834, 0.606, 0.523, 0.464 (µg/100 g); folates 0.730, 2.390, 2.440, 2.420, 2.330 (µg/100 g). The levels of B-vitamins presented regional differences and varied significantly among different lactation stages. The inversely associations of thiamine, vitamin B6, and folates with maternal BMI were found in multivariate analyses (p < 0.05), as well as higher pantothenic acid, folates, and biotin concentrations in lactating women with supplement intake when compared with those without (p < 0.05). Riboflavin concentrations associated with regular exercise was found in multivariate analyses (p < 0.05). CONCLUSIONS: The present study indicated regional and socioeconomic factors, lactation stage, and supplement intake may influence B-vitamins concentrations of human milk in healthy Chinese mothers. Further studies on accurate and complete analysis of all vitamin forms are crucial for giving a more comprehensive understanding of vitamin status in human milk. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01971671. Registered 13 October 2013.