Dietary Isothiocyanates: Novel Insights into the Potential for Cancer Prevention and Therapy.

Diet plays an important role in health. A high intake of plant chemicals such as glucosinolates/isothiocyanates can promote optimal health and decrease the risk of cancer. Recent research has discovered more novel mechanisms of action for the effects of isothiocyanates including the modulation of tumor microenvironment, the inhibition of the self-renewal of stem cells, the rearrangement of multiple pathways of energy metabolism, the modulation of microbiota, and protection against Helicobacter pylori. However, the hormetic/biphasic effects of isothiocyanates may make the recommendations complicated. Isothiocyanates possess potent anti-cancer activities based on up-to-date evidence from in vitro and in vivo studies. The nature of hormesis suggests that the benefits or risks of isothiocyanates largely depend on the dose and endpoint of interest. Isothiocyanates are a promising class of cancer-preventative phytochemicals, but researchers should be aware of the potential adverse (and hormetic) effects. In the authors' opinion, dietary isothiocyanates are better used as adjunctive treatments in combination with known anti-cancer drugs. The application of nano-formulations and the delivery of isothiocyanates are also discussed in this review.

Optimization of VCSEL photon lifetime for minimum energy consumption at varying bit rates.

Optimum photon lifetimes of vertical-cavity surface-emitting lasers (VCSELs) are shown to be target bit rate dependent. A comparison of the power budget in fJ/bit for optimized VCSELs operating at 25 Gb/s and 50 Gb/s is given. At 25 Gbit/s, the energy per bit ratio is lower than 100 fJ/bit presenting a 75% reduction as compared to the 50 Gb/s values. The cavity dip / gain peak detuning for maximizing temperature stability must be similarly adjusted to the bit rate as shown here. These conclusions are valid for any VCSELs, e.g. those emitting at 850 nm, 880 nm, 910 nm, 940 nm or 980 nm, presently investigated by us.

High power femtosecond semiconductor lasers based on saw-toothed master-oscillator power-amplifier system with compressed ASE.

High power femtosecond semiconductor laser based on saw-toothed taper mode-locked laser and amplifier was demonstrated with compressed amplified spontaneous emission (ASE). The external-cavity mode-locked taper laser generated the clean optical pulses without any sub-pulse components. A semiconductor optical amplifier (SOA) with tilted taper waveguide and saw-toothed edge reduced evidently the ASE background. The saw-tooth microstructures were optimized and it was found that the saw-tooth of right-right angled triangle showed the best effect. The ratio of the maximum intensity to background radiation was increased by 21.9% and the power was increased by 30.5% due to the saw-tooth microstructure in the SOA. The pulse duration of 495 fs and a peak power over 1.5 kW with repetition rate of 579 MHz were realized after a double-pass grating compressor.

Loss tailoring of high-power broad-area diode lasers.

Broad-area diode lasers (BALs) with high power are highly desirable for a variety of applications. However, such lasers suffer from strongly deteriorated beam quality due to multimode behavior in the lateral direction. In this Letter, we present an approach to flexibly tailor the optical loss of different-order lateral modes by etching micro-holes on the laser mesa with controlled position and numbers. Through arranging the micro-holes at the peak positions of high-order lateral modes with an increasing number from the mesa center to both edges, high-order modes are suppressed due to a larger propagation loss than the fundamental mode. As a result of enhanced mode discrimination, we demonstrate that this technique provides a greatly improved beam quality and about two times higher brightness for 100 µm wide BAL, while maintaining high power and slope efficiency output.

High-brightness diode lasers obtained via off-axis spectral beam combining with selective feedback.

We proposed a modified off-axis spectral beam combining method, based on the concept of selective feedback. A high reflectivity mirror with a fixed width was used to select and couple back the optical modes in the external cavity. The emission power exceeding 20 W with M2 factors of 2.7 × 4.4 in the fast and slow axes was demonstrated. The beam quality of the system was improved by a factor of three to four compared with that of a single emitter, and a high brightness of 190 MW cm-2 str-1 was achieved.

Going beyond the beam quality limit of spectral beam combining of diode lasers in a V-shaped external cavity.

A novel spectral beam combining (SBC) approach based on off-axis feedback in a V-shaped external cavity (VSBC) was proposed and demonstrated. A highly reflecting mirror was used to supply the optical feedback by partial overlapping the beam. The advantages of simple setup, output coupler free, tunable beam quality and emission power over traditional SBC were presented. The beam quality exceeds single emitter with the similar energy conversion efficiency to the traditional SBC. The M2 factors of 2.31 × 3.76 in fast and slow axes and a brightness of 122 MWcm-2sr-1 were realized at 30 A based on a commercial broad-area diode laser array.

Asymmetric light diffraction of two-dimensional electromagnetically induced grating with PT symmetry in asymmetric double quantum wells.

An asymmetric double semiconductor quantum well is proposed to realize two-dimensional parity-time (PT) symmetry and an electromagnetically induced grating. In such a nontrivial grating with PT symmetry, the incident probe photons can be diffracted to selected angles depending on the spatial relationship of the real and imaginary parts of the refractive index. Such results are due to the interference mechanism between the amplitude and phase of the grating and can be manipulated by the probe detuning, modulation amplitudes of the standing wave fields, and interaction length of the medium. Such a system may lead to new approaches of observing PT-symmetry-related phenomena and has potential applications in photoelectric devices requiring asymmetric light transport using semiconductor quantum wells.

Near-diffraction-limited Bragg reflection waveguide lasers.

We report a near-diffraction-limited tapered Bragg reflection waveguide laser (BRL) with a 10 µm ridge width, which is significantly larger than the conventional design. The large mode expansion in the vertical waveguide enables a scalable increase in the ridge width for single lateral mode operation. The role of the taper angle in the performance of tapered BRLs with the intrinsic characteristics of a thick vertical waveguide was investigated. The results indicate that the BRL with a taper angle of 3° shows the best far-field performance. An extremely low vertical divergence angle of 14.5° and a lateral divergence as low as 2.8° for 95% power inclusion were realized. A continuous-wave power exceeding 1 W was demonstrated. Over the entire operating current range, the vertical beam is almost unchanged with an excellent beam quality (M2) of about 1.3. Lateral beam width increases slightly at higher currents due to the increasing contribution of side lobes, but it still remains nearly diffraction-limited with a lateral M2 of less than 2. Narrow beam divergence and high beam quality of the lasers allow simple and inexpensive collimation and coupling.

Microbiota: a mediator to transform glucosinolate precursors in cruciferous vegetables to the active isothiocyanates.

Isothiocyanates (ITCs), such as sulforaphane (SFN), exhibit powerful biological functions in fighting cancers, and cardiovascular and neurodegenerative diseases. They normally exist as glucosinolates (GLSs) in cruciferous vegetables, which are not themselves bioactive until they are degraded by myrosinase to form ITCs. Myrosinase coexists in the same plants but is normally kept apart from GLSs in different apparatus. A key point is that myrosinase is temperature sensitive and can be inactivated upon exposure to temperatures over 60 °, as typically occurs during cooking. However, studies using animal models and population trials have suggested that human gut bacteria might act like an 'organ' in that they can secrete their own myrosinase. In this review, the hydrolysis of GLS by myrosinase is discussed, with an important focus on the gut microflora and their myrosinase-producing roles. © 2017 Society of Chemical Industry.

Green Synthesis of Nanosilica from Coal Fly Ash and Its Stabilizing Effect on CaO Sorbents for CO2 Capture.

High-temperature sorption of CO2 via calcium looping has wide applications in postcombustion carbon capture, sorption-enhanced hydrogen production, and inherent energy storage. However, fast deactivations of CaO sorbents and low CO2 uptake in the fast carbonation stage are major drawbacks of this technology. For the first time, we developed a green approach through the reuse of nanosilica derived from coal fly ash (CFA) to enhance both the cyclic CO2 uptakes and the sorption kinetics of CaO sorbents. The as-synthesized nanosilica-supported CaO sorbent showed superior cyclic stability even under realistic carbonation/calcination conditions, and maintained a final CO2 uptake of 0.20 g(CO2) g(sorbent)-1 within short carbonation time, markedly increased by 155% over conventional CaO sorbent. Significantly, it also exhibited very fast sorption rate and could achieve almost 90% of the total CO2 uptake within ∼20 s after the second cycle, which is critical for practical applications. These positive effects were attributed to the formation of larnite (Ca2SiO4) and the physical nanostructure of silica, which could yield and keep abundant reactive small pores directly exposed to CO2 throughout multiple cycles. The proposed strategy, integrating the on-site recycling of CFA, appears to be promising for CO2 abatement from coal-fired power plants.

Low lateral divergence 2 µm InGaSb/ AlGaAsSb broad-area quantum well lasers.

High power and high brightness mid-infrared GaSb based lasers are desired for many applications, however, the high lateral divergence is still the influence factor for practical application. In this paper, a simple and effective approach based on the fishbone-shape microstructure was proposed, the effective improvement on both the lateral divergence and output power of 2 µm GaSb based broad-area lasers was demonstrated. The lateral divergence is reduced averagely by 55% and 15.8° for 95% power content is realized. The continuous-wave emission power is increased about 19% with the decreased threshold current. The other merits for this microstructure are the unchanged intrinsic characteristic of broad-area lasers and the low cost fabrication.

Controlling odors from sewage sludge using ultrasound coupled with Fenton oxidation.

We examined the effects of ultrasound (U), Fenton oxidation (F), and ultrasound coupled with Fenton oxidation (U + F) pre-treatments (prior to anaerobic digestion) on the elimination of odorous compounds. The results demonstrated that U promoted odor release, while the coupled treatment and F alone decreased odor release. After 20-min treatments, the concentration of dissolved sulfide (S(2-)) under the coupled U + F treatment declined from 17.4 mg/L to 8.1 mg/L, decreasing by more than 50% and 34%, respectively, for U alone and F alone. In addition, the dissolved sulfate (SO4(2-)) concentration under couple U + F treatment significantly increased in sewage sludge from 200 mg/L to 390.6 mg/L, up 95.3% compared to U alone and 5% compared to F alone. This illustrates the oxidation process from S(2-) to SO4(2-). Throughout experimentation, SO4(2-) was odorless and stable, highlighting the mechanism of odor control. Thus, combining U and F into a single coupled treatment proved to be a better alternative pretreatment for controlling sludge odor compared to the U and F alone and can effectively decrease potential odor release.

Synthesis of highly efficient CaO-based, self-stabilizing CO2 sorbents via structure-reforming of steel slag.

Capturing anthropogenic CO2 in a cost-effective and highly efficient manner is one of the most challenging issues faced by scientists today. Herein, we report a novel structure-reforming approach to convert steel slag, a cheap, abundant, and nontoxic calcium-rich industrial waste, as the only feedstock into superior CaO-based, self-stabilizing CO2 sorbents. The CO2 capture capacity of all the steel slag-derived sorbents was improved more than 10-fold compared to the raw slag, with the maximum uptake of CO2 achieving at 0.50 gCO2 gsorbent(-1). Additionally, the initial steel slag-derived sorbent could retain 0.25 gCO2 gsorbent(-1), that is, a decay rate of only 12% over 30 carbonation-calcination cycles, the excellent self-stabilizing property allowed it to significantly outperform conventional CaO, and match with most of the existing synthetic CaO-based sorbents. A synergistic effect that facilitated CO2 capture by CaO-based sorbents was clearly recognized when Mg and Al, the most common elements in steel slag, coexisted with CaO in the forms of MgO and Al2O3, respectively. During the calcium looping process, MgO served as a well spacer to increase the porosity of sorbents together with Al2O3 serving as a durable stabilizer to coresist the sintering of CaCO3 grains at high temperatures.

Impact of ultrasonic treatment on dewaterability of sludge during Fenton oxidation.

Fenton oxidation was compared with Fenton oxidation coupled with ultrasonication (Fenton + US) for sludge dewatering. Different Fenton reagent (H2O2, Fe(2+)) concentrations, pH, and reaction times were studied in different systems on the basis of the specific resistance to filtration (SRF) and capillary suction time (CST). It was found that Fenton + US can significantly reduce Fe(2+) and H2O2 dosages and reaction times. After ultrasonication of the system at pH 3, with an ultrasonic frequency of 25 kHz and a sound energy density of 100 W/L, the Fe(2+), H2O2 dosage, and reaction time were reduced by 66.7, 75.0, and 75.0 %, respectively, when compared with Fenton oxidation at the same dewaterability of sludge. The microstructure of sludge and hydroxyl radical (·OH) density in Fenton oxidation and Fenton + US was further examined. Fenton + US produced more · OH in a sludge system than did individual Fenton oxidation. The concentration of · OH in Fenton + US fell from 79.2 to 6 mg/L over 3.5 h, while the concentration of · OH in Fenton oxidation fell from 59.6 to 1 mg/L over 2 h, thus destroying the microstructure of sludge more effectively. Sludge treated using Fenton + US for 30 min showed a much thinner and looser microstructure.

Pressure-Induced Enhancement in Chemical Looping Reforming of CH4: A Thermodynamic Analysis with Fe-Based Oxygen Carriers.

Chemical looping reforming of methane (CLRM) with Fe-based oxygen carriers is widely acknowledged as an environmentally friendly and cost-effective approach for syngas production, however, sintering-caused deactivate of oxygen carriers at elevated temperatures of above 900 °C is a longstanding issue restricting the development of CLRM. Here, in order to reduce the reaction temperature without compromising the chemical-looping CH4 conversion efficiency, we proposed a novel operation scheme of CLRM by manipulating the reaction pressure to shift the equilibrium of CH4 partial oxidation towards the forward direction based on the Le Chatelier's principle. The results from thermodynamic simulations showed that, at a fixed reaction temperature, the reduction in pressure led to the increase in CH4 conversion, H2 and CO selectivity, as well as carbon deposition rate of all investigated oxygen carriers. The pressure-negative CLRM with Fe3O4, Fe2O3 and MgFe2O4 could reduce the reaction temperature to below 700 °C on the premise of a satisfactory CLRM performance. In a comprehensive consideration of the CLRM performance, energy consumption, and CH4 requirement, NiFe2O4 was the Fe-based OCs best available for pressure-negative CLRM, especially for an excellent syngas yield of 23.08 mmol/gOC. This study offered a new strategy to address sintering-caused deactivation of materials in chemical looping from the reaction thermodynamics point of view.

Multi-omics insight into the metabolic and cellular characteristics in the pathogenesis of hypothyroidism.

While circulating metabolites and immune system have been increasingly linked to hypothyroidism risk, the causality underlying these associations remains largely uninterrogated. We used Mendelian randomization to identified putative causal traits for hypothyroidism via integrating omics data. Briefly, we utilized 1180 plasma metabolites and 731 immune cells traits as exposures to identify putatively causal traits for hypothyroidism in the discovery (40,926 cases) and replication cohorts (14,871 cases). By combining MR results from two large-scale cohorts, we ultimately identified 21 putatively causal traits, including five plasma metabolites and 16 immune cell traits. CD3 on CD28+ CD4+ T cell and 1-(1-enyl-palmitoyl)-2-oleoyl-GPE (p-16:0/18:1) demonstrated the most pronounced positive and negative associations with hypothyroidism risk, respectively. The odds ratio and 95% confidence interval were 1.09 (1.07, 1.12) and 0.81 (0.75, 0.87), respectively. No evidence of horizontal pleiotropy, heterogeneity among instrumental variables or reverse causation were found for these 21 significant associations. Our study elucidates key metabolites and immune cell traits associated with hypothyroidism. These findings provide new insights into the etiology and potential therapeutic targets for hypothyroidism.

Improving insulin resistance by sulforaphane via activating the Bacteroides and Lactobacillus SCFAs-GPR-GLP1 signal axis.

Background: Insulin resistance (IR) is closely associated with non-alcoholic fatty liver disease (NAFLD), and the gut microbiome contributes to the development of NAFLD. Sulforaphane (SFN) is a phytochemical in cruciferous vegetables that could improve lipid metabolism disorder. However, whether SFN can alleviate IR in NAFLD by regulating the intestinal flora remains unclear. Methods: SFN was administered to high fat diet (HFD)-fed Wistar rats for 10 weeks. Gut microbiota was analysed by 16S rRNA sequencing and the short chain fatty acids (SCFAs) by gas chromatography. The expression of tight junction protein and the numbers of Lactobacillus, Bacteroides and Bifidobacterium were determined by qPCR. The expression of G-protein-coupled receptor 41/43 (GPR41/43) was determined by western blot. A randomized controlled trial (RCT) was conducted in NAFLD patients with broccoli seed tablets (rich in SFN, 42 mg d-1) as intervention for 12 weeks. Thirty-six volunteers with abnormal glucose before the broccoli seed tablet treatment were selected in the intervention group to analyze their blood glucose, insulin, homeostasis model assessment-insulin resistance index (HOMA-IRI), homeostasis model assessment-insulin sensitivity index (HOMA-ISI) and glucagon-like peptide (GLP-1). Results: SFN reduced blood glucose and HOMA-IRI while increasing insulin sensitivity in HFD rats. SFN reduced glycogen synthase kinase 3 (GSK-3), phosphoenolpyruvate carboxykinase (PEPCK) activity, and phosphorylation of serine residues of IRS-2 induced by HFD. SFN reshaped the gut microbiota composition of HFD-induced rats and, especially, increased the content of Bacteroidaceae, Lactobacillaceae and Bifidobacteriaceae, which are related to the improvement from SFN of the blood glucose and HOMA-IRI. The increased numbers of Bacteroides and Lactobacillus were the targets of SFN to enhance the expression of tight junction proteins ZO-1 and occludin, thereby lowering lipopolysaccharide content to reduce inflammation, ultimately alleviating IR. Bacteroides and Lactobacillus produced SCFAs, which activated GPR41/43 to secrete GLP1. Moreover, it was also confirmed in RCT that SFN intervention increased the level of GLP1 in NAFLD patients, which was positively correlated with the reduction of blood glucose and HOMA-IR. Conclusions: SFN alleviated IR in NAFLD via the Bacteroides and Lactobacillus SCFAs-GPR41/43-GLP1 axis and protected the intestinal mucosal barrier to decrease inflammation.

Influence of SO2 in incineration flue gas on the sequestration of CO2 by municipal solid waste incinerator fly ash.

The influence of CO2 content and presence of SO2 on the sequestration of CO2 by municipal solid waste incinerator (MSWI) fly ash was studied by investigating the carbonation reaction of MSWI fly ash with different combinations of simulated flue gas. The reaction between fly ash and 100% CO2 was relatively fast; the uptake of CO2 reached 87 g CO2/kg ash, and the sequestered CO2 could be entirely released at high temperatures. When CO2 content was reduced to 12%, the reaction rate decreased; the uptake fell to 41 g CO2/kg ash, and 70.7% of the sequestered CO2 could be released. With 12% CO2 in the presence of SO2, the reaction rate significantly decreased; the uptake was just 17 g CO2/kg ash, and only 52.9% of the sequestered CO2 could be released. SO2 in the simulated gas restricted the ability of fly ash to sequester CO2 because it blocked the pores of the ash.

An ultrahigh sensitivity acoustic sensor system for weak signal detection based on an ultrahigh-Q CaF2 resonator.

Acoustic sensors with ultrahigh sensitivity, broadband response, and high resolution are essential for high-precision nondestructive weak signal detection technology. In this paper, based on the size effect of an ultrahigh-quality (Q) calcium fluoride (CaF2) resonator, a weak acoustic signal is detected by the dispersive response regime in which an acoustic, elastic wave modulates the geometry and is converted to a resonance frequency shift. Through the structural design of the resonator, the sensitivity reaches 11.54 V/Pa at 10 kHz in the experiment. To our knowledge, the result is higher than that of other optical resonator acoustic sensors. We further detected a weak signal as low as 9.4 µPa/Hz1/2, which greatly improved the detection resolution. With a good directionality of 36.4 dB and a broadband frequency response range of 20 Hz-20 kHz, the CaF2 resonator acoustic sensing system can not only acquire and reconstruct speech signals over a long distance but also accurately identify and separate multiple voices in noisy environments. This system shows high performance in weak sound detection, sound source localization, sleep monitoring, and many other voice interaction applications.

Observation of the fluorescence spectrum for a driven cascade model system in atomic beam.

We experimentally study the resonance fluorescence from an excited two-level atom when the atomic upper level is coupled by a nonresonant field to a higher-lying state in a rubidium atomic beam. The heights, widths and positions of the fluorescence peaks can be controlled by modifying the detuning of the auxiliary field. We explain the observed spectrum with the transition properties of the dressed states generated by the coupling of the two laser fields. We also attribute the line narrowing to the effects of Spontaneously Generated Coherence between the close-lying levels in the dressed state picture generated by the auxiliary field. And the corresponding spectrum can be viewed as the evidence of Spontaneously Generated Coherence. The experimental results agree well with calculations based on the density-matrix equations.