Entanglement-Enhanced Bioimaging and Sensing

Studies of entangled light-matter interactions have been gaining momentum because of their potential applications in bioimaging and sensing. Entangled photons are predicted to linearize nonlinear optical processes and offer orders of magnitude of enhancement to the interaction cross sections. To investigate the validity of entanglement-enhanced bioimaging techniques, a continuous wave (CW)-powered, on-chip, broadband entangled light source based on periodically poled lithium tantalate (ppLT) was designed and characterized. This light source achieved femtosecond entangled correlation times comparable to classical ultrafast lasers with an unprecedented power of ~100 nW in near-infrared (NIR), which is a crucial first step toward fully integrated, thin-film lithium niobate (TFLN)-based, visible to NIR entangled photon sources. This light source was then used for subsequent spectroscopy/microscopy experiments to systematically investigate the feasibility of entanglement-enabled microscopy techniques such as entangled two-photon absorption (ETPA) microscopy and entangled fluorescence lifetime measurements. A novel method was developed to measure fluorescence from ETPA using a spectrotemporally resolved Michelson interferometer which is good at eliminating false signals due to one-photon absorption and scattering. Careful experimental attempts at detecting virtual-state mediated ETPA from rhodamine 6G (R6G) and resonance-enhanced ETPA from indocyanine green (ICG) were made, and the ETPA signals were found to be below the instrument detection limits and often masked by one-photon effects such as scattering and linear absorption. Instead, experimental upper bounds were placed on the ETPA cross sections of the studied molecules, with an emphasis on continued improvement of the light source and instrument detection limits. On-chip entangled fluorescence lifetime imaging microscopy (entangled-FLIM) has also been identified as a new future development focus. The feasibility of the technique was demonstrated via a proof-of-principle experiment which measured the fluorescence lifetime of ICG in various solvents. Using entangled photons produced from a CW laser, the lifetime measurement scheme achieved a temporal resolution of 50 ps and a minimum measurable lifetime of 365 ps, which can be used to distinguish most biologically relevant fluorophores in the corresponding wavelength range. This experiment is a critical first step toward scalable, high-throughput, wavelength-multiplexed, and on-chip FLIM or lifetime measurements which could be used in label-free health monitoring technologies

Entangled light-matter interactions and spectroscopy

Entangled photons exhibit non-classical light–matter interactions that create new opportunities in materials and molecular science. Notably, in entangled two-photon absorption, the intensity-dependence scales linearly as if only one photon was present. The entangled two-photon absorption cross section approaches but does not match the one-photon absorption cross section. The entangled two-photon cross section also does not follow classical two-photon molecular design motifs. Questions such as these seed the rich but nascent field of entangled light–matter interactions. In this perspective, we use the experimental developments in entangled photon spectroscopy to outline the current status of the field. Now that the fundamental tools are outlined, it is time to start the exploration of how materials, molecules, and devices can control or utilize interactions with entangled photons

Influence of Temperature on Hydrolysis Acidification of Food Waste

AbstractFor two-phase anaerobic digestion process of food waste, degree of hydrolysis and products by acidification during hydrolysis and acidification phase directly affect the performance of methanogenesis phase. Temperature has great impact on hydrolysis and acidification of food waste. This paper monitored the dynamic change of biogas production, biogas composition, pH, soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFAs) during hydrolysis and acidification stage so as to investigate specific influence of temperature on food waste. With the same inoculum and 9 days’ fermentation, three different temperatures (35, 55 and 70°C) were taken into consideration. The results showed that cumulative gas production was 4860mL at 70°C, which was 129.79% and 37.87% higher than that at 35 and 55°C. Besides, hydrogen content at 70°C was 45.34%, which was the highest among the three temperatures. Hydrolysis rate was proportional to the increase of temperature. Meanwhile, total VFAs yield and composition widely differed at three different temperatures. The hydrolysis and acidification products at 35°C were mainly ethanol and acetic acids and the highest concentrations of ethanol at 35°C were 3.28 and 3.65 times of that at 55 and 70°C, but more acetic, isobutyric and butyric acids were generated at 55 and 70°C. Among three temperatures, 70°C had the highest acetic acids concentration while 55°C had the highest isobutyric and butyric acids concentration

Enhancing Hydrogen Evolution Electrocatalytic Performance in Neutral Media via Nitrogen and Iron Phosphide Interactions

It remains a challenge to develop efficient electrocatalysts in neutral media for hydrogen evolution reaction (HER) due to the sluggish kinetics and switch of the rate determining step. Although metal phosphides are widely used HER catalysts, their structural stability is an issue due to oxidization, and the HER performance in neutral media requires improvement. Herein, a new material, i.e., grapevine-shaped N-doped iron phosphide on carbon nanotubes, as an efficient HER catalyst in neutral media is developed. The optimized catalyst shows an overpotential of 256 mV at a large current density of 65 mA cm−2, which is even 10 mV lower than that of the commercial 20% Pt/C catalyst. The excellent performance of the catalyst is further studied by combined computational and experimental techniques, which proves that the interaction between nitrogen and iron phosphides can provide more efficient active structures and stabilize the metal phosphide electrocatalysts for HER

The celiac ganglion modulates LH-induced inhibition of androstenedione release in late pregnant rat ovaries

BACKGROUND: Although the control of ovarian production of steroid hormones is mainly of endocrine nature, there is increasing evidence that the nervous system also influences ovarian steroidogenic output. The purpose of this work was to study whether the celiac ganglion modulates, via the superior ovarian nerve, the anti-steroidogenic effect of LH in the rat ovary. Using mid- and late-pregnant rats, we set up to study: 1) the influence of the noradrenergic stimulation of the celiac ganglion on the ovarian production of the luteotropic hormone androstenedione; 2) the modulatory effect of noradrenaline at the celiac ganglion on the anti-steroidogenic effect of LH in the ovary; and 3) the involvement of catecholaminergic neurotransmitters released in the ovary upon the combination of noradrenergic stimulation of the celiac ganglion and LH treatment of the ovary. METHODS: The ex vivo celiac ganglion-superior ovarian nerve-ovary integrated system was used. This model allows studying in vitro how direct neural connections from the celiac ganglion regulate ovarian steroidogenic output. The system was incubated in buffer solution with the ganglion and the ovary located in different compartments and linked by the superior ovarian nerve. Three experiments were designed with the addition of: 1) noradrenaline in the ganglion compartment; 2) LH in the ovarian compartment; and 3) noradrenaline and LH in the ganglion and ovarian compartments, respectively. Rats of 15, 19, 20 and 21 days of pregnancy were used, and, as an end point, the concentration of the luteotropic hormone androstenedione was measured in the ovarian compartment by RIA at various times of incubation. For some of the experimental paradigms the concentration of various catecholamines (dihydroxyphenylalanine, dopamine, noradrenaline and adrenaline) was also measured in the ovarian compartment by HPLC. RESULTS: The most relevant result concerning the action of noradrenaline in the celiac ganglion was found on day 21 of pregnancy resulting in the inhibition of androstenedione release from the ovarian compartment. In addition on day 15 of pregnancy, LH placed in the ovarian compartment led to an inhibition of the release of androstenedione, and this inhibitory effect was further reinforced by the joint action of noradrenaline in the celiac ganglion and LH in the ovary. The levels of catecholamines in the ovarian compartment showed differences among the experiments; of significance, the joint treatment of noradrenaline in the celiac ganglion and LH in the ovary resulted in a remarkable increase in the ovarian levels of noradrenaline and adrenaline when compared to the effect achieved by either one of the compounds added alone. CONCLUSION: Our results demonstrate that the noradrenergic stimulation of the celiac ganglion reinforces the LH-induced inhibition of androstenedione production by the ovary of late pregnant rats, and that this effect is associated with marked changes in the release of catecholamines in the ovary

Th Inducing POZ-Kruppel Factor (ThPOK) Is a Key Regulator of the Immune Response since the Early Steps of Colorectal Carcinogenesis

We purposed to evaluate the role of Th inducing POZ-Kruppel Factor (ThPOK), a transcriptional regulator of T cell fate, in tumour-induced immune system plasticity in colorectal carcinogenesis. The amounts of CD4+, CD8+ and CD56+ and ThPOK+ cells infiltrate in normal colorectal mucosa (NM), in dysplastic aberrant crypt foci (microadenomas, MA), the earliest detectable lesions in colorectal carcinogenesis, and in colorectal carcinomas (CRC), were measured, and the colocalization of ThPOK with the above-mentioned markers of immune cells was evaluated using confocal microscopy. Interestingly, ThPOK showed a prominent increase since MA. A strong colocalization of ThPOK with CD4 both in NM and in MA was observed, weaker in carcinomas. Surprisingly, there was a peak in the colocalization levels of ThPOK with CD8 in MA, which was evident, although to a lesser extent, in carcinomas, too. In conclusion, according to the data of the present study, ThPOK may be considered a central regulator of the earliest events in the immune system during colorectal cancer development, decreasing the immune response against cancer cells

miR-17–92 cluster: ups and downs in cancer and aging

The miR-17–92 cluster encoding 6 single mature miRNAs was identified a couple of years ago to contain the first oncogenic miRNAs. Now, one of these 6 miRNAs, miR-19 has been identified as the key responsible for this oncogenic activity. This in turn reduces PTEN levels and in consequence activates the AKT/mTOR pathway that is also prominently involved in modulation of organismal life spans. In contrast, miR-19 and other members of the miR-17–92 cluster are found to be commonly downregulated in several human replicative and organismal aging models. Taken together, these findings suggest that miR-19 and the other members of the miR-17–92 cluster might be important regulators on the cross-roads between aging and cancer. Therefore, we here briefly summarize how this cluster is transcriptionally regulated, which target mRNAs have been confirmed so far and how this might be linked to modulation of organismal life-spans

Growth-inhibitory effects of the chemopreventive agent indole-3-carbinol are increased in combination with the polyamine putrescine in the SW480 colon tumour cell line

BACKGROUND: Many tumours undergo disregulation of polyamine homeostasis and upregulation of ornithine decarboxylase (ODC) activity, which can promote carcinogenesis. In animal models of colon carcinogenesis, inhibition of ODC activity by difluoromethylornithine (DFMO) has been shown to reduce the number and size of colon adenomas and carcinomas. Indole-3-carbinol (I3C) has shown promising chemopreventive activity against a range of human tumour cell types, but little is known about the effect of this agent on colon cell lines. Here, we investigated whether inhibition of ODC by I3C could contribute to a chemopreventive effect in colon cell lines. METHODS: Cell cycle progression and induction of apoptosis were assessed by flow cytometry. Ornithine decarboxylase activity was determined by liberation of CO(2 )from (14)C-labelled substrate, and polyamine levels were measured by HPLC. RESULTS: I3C inhibited proliferation of the human colon tumour cell lines HT29 and SW480, and of the normal tissue-derived HCEC line, and at higher concentrations induced apoptosis in SW480 cells. The agent also caused a decrease in ODC activity in a dose-dependent manner. While administration of exogenous putrescine reversed the growth-inhibitory effect of DFMO, it did not reverse the growth-inhibition following an I3C treatment, and in the case of the SW480 cell line, the effect was actually enhanced. In this cell line, combination treatment caused a slight increase in the proportion of cells in the G(2)/M phase of the cell cycle, and increased the proportion of cells undergoing necrosis, but did not predispose cells to apoptosis. Indole-3-carbinol also caused an increase in intracellular spermine levels, which was not modulated by putrescine co-administration. CONCLUSION: While indole-3-carbinol decreased ornithine decarboxylase activity in the colon cell lines, it appears unlikely that this constitutes a major mechanism by which the agent exerts its antiproliferative effect, although accumulation of spermine may cause cytotoxicity and contribute to cell death. The precise mechanism by which putrescine enhances the growth inhibitory effect of the agent remains to be elucidated, but does result in cells undergoing necrosis, possibly following accumulation in the G(2)/M phase of the cell cycle