High-efficiency grating coupler for an ultralow-loss Si3N4-based platform.

Integrated silicon nitride waveguides of 100 nm height can achieve ultralow propagation losses below 0.1 dB/cm at the 1550 nm wavelength band but lack the scattering strength to form efficient grating couplers. An enhanced grating coupler design based on an amorphous silicon layer on top of silicon nitride is proposed and demonstrated to improve the directionality of the coupler. The fabrication process is optimized for a self-alignment process between the amorphous silicon and silicon nitride layers without increasing waveguide losses. Experimental coupling losses of 5 dB and a 3 dB bandwidth of 75 nm are achieved with both regular and focusing designs.

Thyroid as a target of adjuvant autoimmunity/inflammatory syndrome due to mRNA-based SARS-CoV2 vaccination: from Graves' disease to silent thyroiditis.

BACKGROUND: As COVID-19 became a pandemic, the urgent need to find an effective treatment vaccine has been a major objective. Vaccines contain adjuvants which are not exempt from adverse effects and can trigger the autoimmune/inflammatory syndrome induced by adjuvants (ASIA). There is very little information about autoimmune endocrine disease and the ASIA after the use of mRNA-based SARS-CoV2 vaccination. CASE SERIES: We report three cases and also review the literature showing that the thyroid gland can be involved in the ASIA induced by the mRNA-based SARS-CoV2 vaccination. We present the first case to date of silent thyroiditis described in the context of SARS-CoV2 vaccination with Pfizer/BioNTech. Also, we discuss the first subacute thyroiditis in the context of SARS-CoV2 vaccination with the Moderna's vaccine. Finally, we provide another case to be added to existing evidence on Graves' disease occurring post-vaccination with the Pfizer/BioNTech vaccine. DISCUSSION: Adjuvants play an important role in vaccines. Their ability to increase the immunogenicity of the active ingredient is necessary to achieve the desired immune response. Both the Moderna and the Pfizer/BioNTech vaccines use mRNA coding for the SARS-CoV2 S protein enhanced by adjuvants. In addition, the cross-reactivity between SARS-CoV2 and thyroid antigens has been reported. This would explain, at least, some of the autoimmune/inflammatory reactions produced during and after SARS-CoV2 infection and vaccination. CONCLUSION: The autoimmune/inflammatory syndrome induced by adjuvants involving the thyroid could be an adverse effect of SARS-CoV2 vaccination and could be underdiagnosed.

Differences in the cluster of depressive symptoms between subjects with type 2 diabetes and individuals with a major depressive disorder and without diabetes.

BACKGROUND: Depressive disorder encompasses a wide spectrum of somatic and psychological symptoms. It is not known whether there are differences regarding the cluster of depressive symptomatology between subjects with depression with and without T2DM. PURPOSE: To explore whether the cluster of depression that prevails among depressive subjects with T2DM differs from individuals with depression, but without T2DM. METHODS: 87 T2DM patients with a pathological Beck Depression Inventory test (BDI) were compared with 50 age- and gender-matched individuals with a major depressive disorder. All 21 items expressed in the BDI were compared between the two groups. RESULTS: The score obtained after administering the BDI was comparable between patients with T2DM and significant depressive symptoms and the control group (18.8 ± 2.7 vs 18.9 ± 3.4; p = 0.9). Subjects with T2DM had higher scores compared with the control group in the following items: sadness (1.4 ± 0.9 vs 0.9 ± 0.9; p = 0.011), difficulty in concentration (1.3 ± 0.8 vs 0.8 ± 0.8; p = 0.01), indecisiveness (1.1 ± 0.8 vs 0.5 ± 0.9; p = 0.012), worries about their health (1.3 ± 0.9 vs 0.6 ± 0.9; p < 0.0001), fatigue (1.2 ± 0.6 vs 0.8 ± 0.7; p = 0.003) and loss of sexual appetite (2.7 ± 0.6 vs 1.2 ± 1.3; p = 0.0001). Suicidal ideation was significantly lower among subjects with T2DM compared with the control group (0.1 ± 0.3 vs 0.6 ± 0.8; p = 0.0001). CONCLUSIONS: Subjects with T2DM and a positive screening for depression presented a different cluster of depression compared with depressed subjects without T2DM, with a predominance of somatic-biological depressive symptoms rather than psychological-cognitive cluster and negative emotions, such as suicidal ideation.

Compact focusing grating couplers for silicon horizontal slot waveguides.

In this Letter, we present the design, simulation (2D and 3D), fabrication, and experimental characterization of compact and fully etched focusing gratings for a horizontal slot waveguide based on a silicon nitride layer sandwiched between amorphous silicon and a silicon-on-insulator. The measured coupling losses are about 4 dB with a 3 dB bandwidth of 38 nm. The fully etched configuration allows the fabrication in a single lithography step.

Ultra-compact TE and TM pass polarizers based on vanadium dioxide on silicon.

Vanadium dioxide (VO(2)) is a metal-insulator transition (MIT) oxide recently used in plasmonics, metamaterials, and reconfigurable photonics. Because of the MIT, VO(2)shows great change in its refractive index allowing for ultra-compact devices with low power consumption. We theoretically demonstrate a transverse electric (TE) and a transverse magnetic (TM) pass polarizer with an ultra-compact length of only 1 µm and tunable using the MIT of the VO2. During the insulating phase, both devices exhibit insertion losses below 2 dB at 1550 nm. Changing to the metallic phase, the unwanted polarization is attenuated above 15 dB while insertion losses are kept below 3 dB. Broadband operation over a range of 60 nm is also achieved.

Broadband 8 µm long hybrid silicon-plasmonic transverse magnetic-transverse electric converter with losses below 2 dB.

A novel ultracompact (8 µm length) hybrid silicon-plasmonic TM-TE converter is reported. The conversion is achieved during a partial power coupling between a waveguide and a hybrid plasmonic parallel waveguide. The impact of different types of metals is also analyzed. At a wavelength of 1.55 µm, the device has an extinction ratio (ER) of 27.6 dB and insertion loss (IL) of 1.75 dB. Furthermore, an optical bandwidth as large as 100 nm is achieved with ERs higher than 25 dB and ILs below 2 dB.

Increased sensitivity through maximizing the extinction ratio of SOI delay-interferometer receiver for 10G DPSK.

We present an optimized design for a 10G- differential-phase-shift-keyed (DPSK) receiver based on a silicon-on-insulator (SOI) unbalanced tunable Mach-Zehnder interferometer (MZI) switch in sequence with a Mach-Zehnder delay interferometer (MZDI). The proposed design eliminates the limitation in sensitivity of the device produced by the waveguide propagation losses in the delay line. A 2.3 dB increase in receiver sensitivity at a bit-error-rate (BER) of 10(-9) is experimentally measured over a standard implementation. The enhanced sensitivity is achieved with zero power consumption by tuning the operating wavelength or with less than 5 mW for a fixed wavelength using microheaters. Also the foot-print of the device is minimized to 0.11 mm(2) by the use of compact spirals.

High-contrast 40 Gb/s operation of a 500 µm long silicon carrier-depletion slow wave modulator.

In this Letter, we demonstrate a highly efficient, compact, high-contrast and low-loss silicon slow wave modulator based on a traveling-wave Mach-Zehnder interferometer with two 500 µm long slow wave phase shifters. 40 Gb/s operation with 6.6 dB extinction ratio at quadrature and with an on-chip insertion loss of only 6 dB is shown. These results confirm the benefits of slow light as a means to enhance the performance of silicon modulators based on the plasma dispersion effect.

Silicon slow-light-based photonic mixer for microwave-frequency conversion applications.

We describe and demonstrate experimentally a method for photonic mixing of microwave signals by using a silicon electro-optical Mach-Zehnder modulator enhanced via slow-light propagation. Slow light with a group index of ~11, achieved in a one-dimensional periodic structure, is exploited to improve the upconversion performance of an input frequency signal from 1 to 10.25 GHz. A minimum transmission point is used to successfully demonstrate the upconversion with very low conversion losses of ~7 dB and excellent quality of the received I/Q modulated QPSK signal with an optimum EVM of ~8%.

High speed silicon electro-optical modulators enhanced via slow light propagation.

While current optical communication networks efficiently carry and process huge amounts of digital information over large and medium distances, silicon photonics technology has the capacity to meet the ceaselessly increasing demand for bandwidth via energy efficient, inexpensive and mass producible short range optical interconnects. In this context, handling electrical-to-optical data conversion through compact and high speed electro-optical modulators is of paramount importance. To tackle these challenges, we combine the attractive properties of slow light propagation in a nanostructured periodic waveguide together with a high speed semiconductor pn diode, and demonstrate a highly efficient and mass manufacturable 500 µm-long silicon electro-optical device, exhibiting error free modulation up to 20 Gbit/s. These results, supported by modulation rate capabilities reaching 40 Gbit/s, pave a foreseeable way towards dense, low power and ultra fast integrated networks-on-chip for future chip-scale high performance computing systems.

Effects of Mediterranean diets with low and high proportions of phytate-rich foods on the urinary phytate excretion.

BACKGROUND: Important health benefits have been reported recently to phytate intake. This includes the prevention of pathological calcifications such as renal calculi, dental calculi and cardiovascular calcification, due its action as crystallization inhibitor of calcium salts, and as preventive of cancer. AIM OF STUDY: The aim of this study was to establish a relation between the intake of phytate, through consumption of typical components of the Mediterranean diet (including nuts), and its excretion in urine. METHODS: This study recruited participants from subjects included in a larger trial (PREDIMED) of food habits, that were assigned to one of two diet groups: (1) the Mediterranean diet with low proportion of phytate-rich food group, where participants were asked to maintain their usual diet; and (2) the Mediterranean diet with high proportion of phytate-rich food group, where participants were asked to increase phytate-rich foods in their diet. Phytate intake was assessed on the basis of a food frequency questionnaire. Urinary phytate excretion was determined in 2-h urine samples. RESULTS: The overall phytate consumption of the Mediterranean diet with high proportion of phytate-rich food group (672 +/- 50 mg) was significantly higher than the Mediterranean diet with low proportion of phytate-rich food group (422 +/- 34 mg), representing a 59% difference. Urinary phytate excretion was also significantly higher (54%) in the Mediterranean diet with high proportion of phytate-rich food group (1,016 +/- 70 microg/L) than the Mediterranean diet with low proportion of phytate-rich food group (659 +/- 45 microg/L). CONCLUSIONS: Mediterranean diets high in whole cereals, legumes and nuts compared to Mediterranean diets low in these phytate-rich foods increase the urinary phytate excretion in humans.

Strong electro-optical modulation enhancement in a slow wave corrugated waveguide.

We modelled strong slow wave modulation enhancement in a rib corrugated waveguide with respect to a conventional rib waveguide, both embedded in a reverse biased pn junction. This enhancement is characterized in terms of effective index change versus reverse bias variations from 0V to -10V and for moderate group velocities varying in the range 0.02c to 0.15c. Interaction lengths and insertion losses below 750 microm and 3dB are respectively found for voltage variations in the range -8V to -10V. Furthermore, the device electrical modulation bandwidth is expected to be higher than 10 GHz.

High-speed modulation of a compact silicon ring resonator based on a reverse-biased pn diode.

High speed modulation based on a compact silicon ring resonator operating in depletion mode is demonstrated. The device exhibits an electrical small signal bandwidth of 19 GHz. The device is therefore a candidate for highly compact, wide bandwidth modulators for a variety of applications.

Anticalculus effect of a triclosan mouthwash containing phytate: a double-blind, randomized, three-period crossover trial.

BACKGROUND AND OBJECTIVE: Dental calculus occurs as a consequence of supersaturation of saliva with respect to calcium phosphates. This mineralization of dental plaque can be delayed by the presence of crystallization inhibitors, such as pyrophosphate or bisphosphonates. Phytate inhibits brushite and hydroxyapatite crystallization and has the potential to prevent dental calculi formation. The aim of the present study was to examine the effects of phytate and zinc, administered in a mouthwash solution, to prevent the formation of dental calculus. MATERIAL AND METHODS: Healthy dental plaque-forming volunteers (n = 25) took part in a randomized, double-blind, three-period crossover clinical study to assess the efficacy of a phytate-containing mouthwash in relation to control and placebo effects. Subjects rinsed their mouths for 1 min, twice each day, with 20 mL of the test solution, without ingestion. Mouthwash efficacy was assessed through quantification of the amounts of calcium, phosphorus and magnesium present in the residues obtained by dental cleaning, performed by a single trained examiner. RESULTS: A good correlation was found among total calcium, magnesium and phosphorus in calcified dental plaque residues, indicating that any of these variables is adequate for evaluating the reduction of plaque crystallization as calcium phosphate. A statistically significant decrease in total calcium, magnesium and phosphorus was found in the phytate-treatment period compared with control and placebo periods, demonstrating the efficacy of the proposed treatment in reducing dental calculus formation. CONCLUSION: The high efficacy of phytate in reducing dental calculus formation suggests that this substance may be an effective treatment for preventing the development of calculus deposits.

Possible relation between consumption of different food groups and depression.

BACKGROUND: Diverse studies have investigated the relationship between diet and depression. In fact some cross-sectional studies suggested that a healthy diet reduced the risk for depression. The main objective of this study was to assess the relationship of consumption of different food groups with depression. The food groups were selected based on their content of substances that were precursors to neurotransmitters (tryptophan or inositol) or their effect on oxidative stress. METHODS: This observational retrospective study compared the diets of individuals who were with depressive symptoms (Beck Depression Inventory Questionnaire [BDI] ≥ 10; 53 women, 23 men, age 38+/- 11) and with no depressive levels (BDI < 10; 33 women, 23 men, age 41+/- 13). Dietary data were collected from a questionnaire that asked about consumption of legumes, nuts, whole-grain foods, fruits and vegetables, chocolate, and sweet foods and refined sugars. RESULTS: Depressed individuals consumed significantly lower amounts of legumes, fruits, and vegetables, but higher amounts of sweets and refined sugars (p < 0.05 for all comparisons). After statistical adjustment for age and sex, the consumption of no legumes (adjusted odds ratio [aOR] = 2.60, 95% confidence interval [CI] = 1.19-5.67), low consumption of fruits and vegetables (aOR = 2.69, 95% CI = 1.18-6.13), and high consumption of sweet foods and refined sugars (aOR = 1.91, 95% CI = 1.23-2.99) were significantly associated with depression. The two groups had no significant differences in the consumption of chocolate. DISCUSSION: The results indicate significant relationships of the consumption of certain foods with depression, although the study design precludes any conclusions regarding causality. Further studies are necessary to determine the causal relationships of the consumption of specific foods with depression, and of depression with the consumption of specific foods. CONCLUSION: In spite of the limitations, we find that individuals without depression consumed more legumes, fruits, and vegetables, but fewer sweets and pastries than those with depression.

Polarization insensitive low-loss coupling technique between SOI waveguides and high mode field diameter single-mode fibers.

A polarization insensitive technique for highly efficient coupling between SOI waveguides and high mode field diameter single-mode fibers is reported. The proposed coupling structure is based on an inverted taper structure coupled to a fiber-adapted waveguide. The fiber-adapted waveguide is made by using the SiO(2) layer under the Si waveguiding layer of the SOI wafer thus avoiding the use of extra materials such as polymers. The proposed coupling structure is aimed for being integrated with V-groove auto-alignment techniques. Coupling losses of 3.5dB and 3.7dB to 8mum mode field diameter single-mode fibers have been estimated by means of 3D-BPM simulations for TE and TM polarizations respectively and a 1550nm input signal wavelength.

Factors affecting calcium oxalate dihydrate fragmented calculi regrowth.

BACKGROUND: The use of extracorporeal shock wave lithotripsy (ESWL) to treat calcium oxalate dihydrate (COD) renal calculi gives excellent fragmentation results. However, the retention of post-ESWL fragments within the kidney remains an important health problem. This study examined the effect of various urinary conditions and crystallization inhibitors on the regrowth of spontaneously-passed post-ESWL COD calculi fragments. METHODS: Post-ESWL COD calculi fragments were incubated in chambers containing synthetic urine varying in pH and calcium concentration: pH = 5.5 normocalciuria (3.75 mM), pH = 5.5 hypercalciuria (6.25 mM), pH = 6.5 normocalciuria (3.75 mM) or pH = 6.5 hypercalciuria (6.25 mM). Fragment growth was evaluated by measuring increases in weight. Fragment growth was standardized by calculating the relative mass increase. RESULTS: Calcium oxalate monohydrate (COM) crystals formed on COD renal calculi fragments under all conditions. Under pH = 5.5 normocalciuria conditions, only COM crystals formed (growth rate = 0.22 +/- 0.04 microg/mg x h). Under pH = 5.5 hypercalciuria and under pH = 6.5 normocalciuria conditions, COM crystals and a small number of new COD crystals formed (growth rate = 0.32 +/- 0.03 microg/mg x h and 0.35 +/- 0.05 microg/mg x h, respectively). Under pH = 6.5 hypercalciuria conditions, large amounts of COD, COM, hydroxyapatite and brushite crystals formed (growth rate = 3.87 +/- 0. 34 microg/mg x h). A study of three crystallization inhibitors demonstrated that phytate completely inhibited fragment growth (2.27 microM at pH = 5.5 and 4.55 microM at pH = 6.5, both under hypercalciuria conditions), while 69.0 microM pyrophosphate caused an 87% reduction in mass under pH = 6.5 hypercalciuria conditions. In contrast, 5.29 mM citrate did not inhibit fragment mass increase under pH = 6.5 hypercalciuria conditions. CONCLUSION: The growth rate of COD calculi fragments under pH = 6.5 hypercalciuria conditions was approximately ten times that observed under the other three conditions. This observation suggests COD calculi residual fragments in the kidneys together with hypercalciuria and high urinary pH values may be a risk factor for stone growth. The study also showed the effectiveness of specific crystallization inhibitors in slowing calculi fragment growth.

Absorption of myo-inositol hexakisphosphate (InsP6) through the skin in humans.

In this paper, we present a pilot study of the absorption of myo-inositol hexakisphosphate (InsP6) through the skin in humans. We found that, after topical treatment with a 4% InsP6 rich gel, InsP6 urinary excretion increased 54% compared to the control situation (participants submitted to an InsP6-poor diet for 15 days, n = 6), clearly demonstrating that InsP6 is absorbed through the skin of humans. These results demonstrate the topical application as a suitable administration route of InsP6 in humans.

Anxiety and stress among science students. Study of calcium and magnesium alterations.

Stress and anxiety of university science students (Chemistry) was evaluated in basal conditions and during exams using validated stress and anxiety questionnaires. The relations between the data obtained and various biochemical markers were established. Results showed that the evaluated students did not experience stress increase as a consequence of exams but suffered a significant increase in anxiety. The psychological findings agree with the urinary biomarkers studied. It is known that anxiety is related to partial magnesium reduction associated with a urinary magnesium excretion increase, as observed in the present data. Nevertheless, stress also correlates with a urinary calcium increase which was not detected in the present study.

Prevalence and Clinical Correlators of Undiagnosed Significant Depressive Symptoms Among Individuals with Type 2 Diabetes In A Mediterranean Population.

Objective: To determine the frequency and clinical parameters, of clinically significant depressive symptoms among a type 2 diabetes (T2DM) sample from a Mediterranean area without an established diagnosis of depressive disorder (DD). Methods: 320 subjects with T2DM were recruited randomly from Primary-Care settings and the Endocrine Department from a tertiary center in Mallorca (Spain). 91 healthy individuals matched by age, gender and BMI were used as controls. All participating patients graded by the presence of DD by using the "Beck Depression Inventory" (BDI), considering pathological a cut-off score equal or greater than 16. Results: 27.2% T2DM subjects had significant symptoms of DD compared with 12.1% in the control group (p<0.01). BDI score was higher among T2DM when compared with controls (12±9.6 vs. 7.4±5, p<0.0001). The proportion of females (68% vs. 37%, p<0.0001), subjects without an active job (68% vs. 45%, p=0.01) and singles (38% vs. 18%, p=0.007) was greater among T2DM with a BDI≥16. Subjects with criteria for DD had a higher BMI (31.99±5.96 vs. 30.53±5.62, p=0.03). Fasting plasma glucose was higher among T2DM with a BDI≥16 (162±70 vs. 147±45 mg/dl, p=0.02) as well as HbA1c levels (7.9±1.8% vs. 7.4±1.4%, p=0.01), triglycerides (203±183 vs. 161±103 mg/dl; p=0.03) and LDL-cholesterol (112±31 vs. 104±35 mg/dl; p=0.03). Gender, marital status, BMI and triglycerides were independently related to the presence of DD after a logistic regression model. Conclusions: Relevant depressive symptoms are more prevalent among Mediterranean T2DM subjects than in general population. Main clinical correlators of significant depressive symptoms are gender, marital status and BMI.