Measuring Local pKa and pH Using Surface Enhanced Raman Spectroscopy of 4-Mercaptobenzoic Acid.

We report spectroscopic measurements of the local pH and pKa at an electrode/electrolyte interface using surface enhanced Raman scattering (SERS) spectroscopy of 4-mercaptobenzoic acid (4-MBA). In acidic and basic solutions, the protonated and deprotonated carboxyl functional groups at the electrode surface exist in the solution as -COOH and -COO-, which have different Raman active vibrational features at around 1697 and 1414 cm-1, respectively. In pH neutral water, as the applied electrochemical potential is varied from negative to positive, the acidic form of the 4-MBA (i.e., -COOH) decreases in Raman intensity and the basic form (i.e., -COO-) increases in Raman intensity. The change in local ion concentration is due to the application of electrochemical potentials and the accumulation of ions near the electrode surface. Under various applied potentials, the ratio of 1697 and 1587 cm-1 (pH-independent) peak areas spans the range between 0.7 and 0, and the ratio of the 1414 and 1587 cm-1 peak areas ranges from 0 to 0.3. By fitting these data to a normalized sigmoid function, we obtain the percentage of surface protonation/deprotonation, which can be related to the pKa and pH of the system. Thus, we can measure the local pKa at the electrode surface using the surface enhanced Raman signal of the 4-MBA.

Staged transverse preputial island flap urethroplasty for some proximal hypospadias with moderate-to-severe chordee.

BACKGROUND: We aimed to assess the outcome of staged transverse preputial island flap (TPIF) urethroplasty for repairing certain cases of primary proximal hypospadias with moderate-to-severe chordee in children. METHODS: Nighty-two consecutive boys who underwent either one-stage or staged TPIF urethroplasty for the repair of proximal hypospadias with moderate-to-severe chordee between August 2015 and December 2019 were evaluated retrospectively. Patients were divided into two groups: one-stage TPIF urethroplasty group (n = 44) and staged TPIF urethroplasty group (n = 48). We noted and compared the postoperative complications, including urethrocutaneous fistula, urethral diverticula, residual penile curvature, and urethral stricture in both groups. RESULTS: Both groups were followed up for 1-5 years, with an average of 3 years. No cases of residual or recurrence of penile chordee were reported in either group. In Group A, 9 patients (9/44, 20.4%) had postoperative urethrocutaneous fistula, and all patients underwent urinary fistula repair or urethroplasty. In Group B, postoperative urethrocutaneous fistula occurred in 2 cases (2/48, 4.1%), and one patient developed a urethrocutaneous fistula after the first operation, which was successfully repaired during the second operation. A urethrocutaneous fistula occurred in 1 case after completion of the second-stage operation; urethral fistula repair was performed successfully 6 months later. There were 2 cases of urethral stricture in Group A (2/44, 4.5%) and none in Group B. There were 6 cases of urethral diverticulum in Group A (6/44, 13.6%) and no cases of urethral diverticulum in Group B. The operative success rates were 61.3% and 95.8% in Group A and Group B, respectively (P < 0.001). CONCLUSIONS: Compared with one-stage TPIF urethroplasty, staged TPIF urethroplasty in the treatment of certain cases of primary proximal hypospadias with moderate-to-severe chordee resulted in fewer postoperative fistulas, urethral strictures and urethral diverticula. The staged TPIF urethroplasty procedure was effective in reducing the operation difficulty and complication rate of hypospadias, improving the curative effect of complex hypospadias and having good clinical application value.

Low Reducing Potentials Enabled by CaF2-Supported Graphene Electrodes in High Impedance Solutions.

We report electrochemical measurements using in situ Raman spectroscopy at graphene/D2O interfaces under extremely low applied potentials. Here, the hydrophobic and catalytically inert nature of graphene and the insulating nature of the deionized (DI) water enables potentials as low as Vapplied = -7 V vs Ag/AgCl to be applied without exceeding 200 µA/cm2 of current density. At higher currents, bubble formation (i.e., hydrogen evolution reaction) prohibits reliable spectra from being obtained from the electrode surface. Using CaF2 as the supporting substrate enables significantly lower reducing potentials to be reached compared to glass substrates, likely due to trapped charge and impurities in the glass substrate. G band Raman spectra taken under various applied electrochemical potentials exhibit a linear relationship between the G band shift (ΔωG) and the applied potential, with blueshifts as high as ΔωG = 18 cm-1. These large Raman shifts indicate a large change in the Fermi level of ΔEF = -0.43 eV for graphene electrodes in contact with water, favoring reduction half-reactions. Based on the solution resistance measurement, there is a VIR = 3.1 V voltage drop across the solution for D2O (when the applied potential was Vapplied = -7 V vs Ag/AgCl) and the effective reducing potential on the working electrode is Veffective = -3.9 V vs Ag/AgCl. We have also tested these graphene electrodes in ionic liquids [DEME][TFSI], which are limited to applied potentials above Vapplied = -2.7 V vs Ag/AgCl and a corresponding shift in the Fermi level ΔEF = -0.32 eV, indicating that pure water can provide a more robust electrolyte for reaching low reducing potentials than ionic liquids.

Photoexcited Hot Electron Catalysis in Plasmon-Resonant Grating Structures with Platinum, Nickel, and Ruthenium Coatings.

We report the electrochemical potential dependence of photocatalysis produced by hot electrons in plasmon-resonant grating structures. Here, corrugated metal surfaces with a period of 520 nm are illuminated with 785 nm wavelength laser light swept as a function of incident angle. At incident angles corresponding to plasmon-resonant excitation, we observe sharp peaks in the electrochemical photocurrent and dips in the photoreflectance consistent with the conditions under which there is wavevector matching between the incident light and the spacing between the lines in the grating. In addition to the bare plasmonic metal surface (i.e., Au), which is catalytically inert, we have measured grating structures with a thin layer of Pt, Ru, and Ni catalyst coatings. For the bare Au grating, we observe that the plasmon-resonant photocurrent remains relatively featureless over the applied potential range from -0.8 to +1.2 V vs NHE. For the Pt-coated grating, we observe a sharp peak around -0.3 V vs NHE, three times larger than the bare Au grating, and near complete suppression of the oxidation half-reaction, reflecting the reducing nature of Pt as a good hydrogen evolution reaction catalyst. The photocurrent associated with the Pt-coated grating is less noisy and produces higher photocurrents than the bare Au grating due to the faster kinetics (i.e., charge transfer) associated with the Pt-coated surface. The plasmon-resonant grating structures enable us to compare plasmon-resonant excitation with that of bulk metal interband absorption simply by rotating the polarization of the light while leaving all other parameters of the experiment fixed (i.e., wavelength, potential, electrochemical solution, sample surface, etc.). A 64X plasmon-resonant enhancement (i.e., p-to-s polarized photocurrent ratio) is observed for the Pt-coated grating compared to 28X for the bare grating. The nickel-coated grating shows an increase in the hot-electron photocurrent enhancement in both oxidation and reduction half-reactions. Similarly, Ru-coated gratings show an increase in hot-electron photocurrents in the oxidation half-reaction compared to the bare Au grating. Plasmon-resonant enhancement factors of 36X and 15X are observed in the p-to-s polarized photocurrent ratio for the Ni and Ru gratings, respectively.

Responses of soil microbial biomass nitrogen to organic fertilizer with different degrees of maturity and regu-lation to soil mineral nitrogen.

By combining the composting process with soil culture experiment, we conducted an experiment with four treatments, including conventional chemical fertilizer (CK), chemical fertilizer + compost maturity reaching 50% germination index (GI, the same below) organic fertilizer (CO1), chemical fertilizer + compost maturity reaching 80% GI organic fertilizer (CO2), chemical fertilizer + compost maturity reaching 100% GI organic ferti-lizer (CO3). We measured soil microbial biomass nitrogen (MBN), mineral nitrogen (NH4+-N, NO3--N), net nitrification rate, microbial biomass carbon (MBC), dissolved organic carbon (DOC), soil urease and soil protease, aiming to reveal the regulatory effect of soil MBN on mineral nitrogen. The results showed that organic fertilizer application significantly increased MBN and NH4+-N concentrations by 50.1%-62.4% and 109.9%-147.1%, reduced NO3--N concentration and net nitrification rate by 23.3%-46.8%, and 26.2%-51.5%, and enhanced MBC, DOC, urease and protease activities by 33.8%-69.6%, 7.4%-20.8%, 11.2%-69.0% and 9.4%-25.1%, respectively. The change ranges of CO2 and CO3 were significantly higher than CO1. Redundancy analysis (RDA) and structural equation model (SEM) results showed that the application of organic fertilizer with higher degree of maturity (GI≥80%) positively regulated soil MBC, MBN, NH4+-N, and the activities of urease and protease, but had a negative effect on soil net nitrification rate. The combined application of chemical fertilizers and high decomposed organic fertilizers could significantly increase soil MBN and NH4+-N contents, as well as soil urease and protease activities, but reduce soil net nitrification rate. To efficiently utilize organic solid wastes, it is recommended to use chemical fertilizer in combination of organic fertilizers with 80% decomposing degree in practical production to reduce the cost in both economy and time.

[Induced differentiation of human adipose-derived stem cells into Leydig cells in vitro].

OBJECTIVE: To explore the feasibility of inducing the differentiation of human adipose tissue-derived stem cells (ADSCs) into Leydig cells in vitro. METHODS: We isolated ADSCs by digestion with Collagenase I from the subcutaneous adipose tissue, cultured them in the DMEM/F12 medium with 10% fetal bovine serum, and detected the expression of vimentin by immunohistochemistry. We exposed the ADSCs to different concentrations of human chorionic gonadotropin (HCG) for different times, determined the expression of StAR mRNA by real-time PCR, and measured the HCG-induced proliferation of ADSCs by MTT. After a week of induction by HCG and DMSO, we conducted 3beta-HSD immunohistochemistry, and detected the testosterone level in the supernatant and lysis of the cells by radioimmunoassay. RESULTS: The ADSCs grew well with a positive expression of vimentin. The expression of the StAR gene was positively correlated with the increased concentration of HCG, reaching the peak at HCG 10 U/ml in 1 week culture. The proliferation of ADSCs was significantly increased by HCG induction. A positive expression of 3beta-HSD was observed after 1 week induction with HCG 10 U/ml and DMSO 3.2 x 10(-6)mol/L. CONCLUSION: HCG enhances the expression of the StAR gene and the proliferation of ADSCs. Induced by HCG 10 U/ml and DMSO 3.2 x 10(-6) mol/L, ADSCs tend to differentiate into Leydig cells.

Enhancement of Ferroelectricity in 5 nm Metal-Ferroelectric-Insulator Technologies by Using a Strained TiN Electrode.

In this work, the ferroelectric characteristic of a 5 nm Hf0.5Zr0.5O2 (HZO) metal-ferroelectric-insulator-semiconductor (MFIS) device is enhanced through strained complementary metal oxide semiconductor (CMOS)-compatible TiN electrode engineering. Strained TiN top-layer electrodes with different nitrogen (N) concentrations are deposited by adjusting the sputtering process conditions. The TiN electrode with 18% N exhibits a compressive characteristic, which induces tensile stress in a 5 nm HZO film. A device with 18% N in TiN shows a higher remanent polarization (2Pr) and larger capacitance value than the compared sample, indicating that the strained TiN is promising for enhancing the ferroelectricity of sub-5 nm HZO devices.

[Change of root morphology in intercropping systems of wheat and faba bean under different phosphorus levels and its relationship with endogenous hormones]. / 不同磷水平下小麦-èš•è±†é—´ä½œæ ¹ç³»å½¢æ€çš„å˜åŒ–åŠå ¶ä¸Žå† æºæ¿€ç´ çš„å ³ç³».

We examined the correlation between changes of root morphology and endogenous hormones in intercropping systems of wheat and faba bean under different phosphorus levels by hydroponics. Compared with monocropping wheat (MW), the intercropping of wheat and faba bean (W∥F) significantly increased root length of wheat, reduced root average diameter of wheat, and increased root surface area under the condition of 1/2P (low P) level. At the conventional phosphorus level, intercropping significantly reduced root average diameter of wheat, and increased root length and root surface area. Compared with monocropping faba bean (MF), W∥F significantly promoted the growth of faba bean root and increased root surface area of faba bean. At the level of 1/2P, intercropping significantly increased the content of auxin (IAA), abscisic acid (ABA), sali-cylic acid (SA) and jasmonic acid (JA). At the conventional phosphorus level, intercropping could significantly increase the content of IAA, ABA and JA in wheat root, while no significant difference in the SA content of wheat root between monocropping and intercropping wheat was found. Intercropping could increase the content of ABA and SA in faba bean roots, but did not affect IAA and JA contents of faba bean roots. There was no significant correlation between the contents of endogenous hormones (IAA, ABA, SA and JA) and root morphology (root length, root average diameter and root surface area) of wheat and faba bean roots in wheat or faba bean monocropping system. In wheat and faba bean intercropping system, there was a positive correlation between IAA contents of wheat and faba bean and their root length and root surface area. W∥F enhanced IAA of wheat and faba bean root, which was an important factor driving the change of root morphology in the intercropping system of wheat and faba bean.

[In utero exposure to dichlorvos induces apoptosis of Leydig cells in rats].

OBJECTIVE: To observe the influence of the organophosphate insecticide dichlorvos on the apoptosis of Leydig cells in the male offspring of the SD rats exposed to dichlorvos, and to investigate the role of the changes of Leydig cells in genitourinary malformation. METHODS: Twenty-one pregnant SD rats were divided into a corn oil control group and 6 dichlorvos groups, the former given by gavage 1.0 ml corn oil daily, and the latter dichlorvos at the dose of 1, 4, 8, 16, 20 and 24 mg/kg daily from the 12th to 17th day of conception. After birth, 5 male neonates were randomly selected from each of the control and dichlorvos groups, and their testes were harvested to be analyzed by HE staining, immunohistochemistry with anti-caspase-3 antibodies and DAPI fluorescent staining. At 90 days after birth, another 5 of the male offspring were taken from each group and their testes were collected for the same analyses. RESULTS: Statistically significant differences were found in the number of both the caspase-3 positive and DAPI labeled Leydig cells in the testes of the rat offspring between the corn oil and the 4, 8, 16, 20 and 24 mg/kg dichlorvos groups (P < 0.05), but not between the control and the 1 mg/kg dichlorvos groups (P > 0.05). The apoptosis of Leydig cells was increased in the male offspring of the dichlorvos-exposed SD rats in a dose-dependent manner. CONCLUSION: Exposure of pregnant rats to dichlorvos can increase the apoptosis of Leydig cells in the male offspring, which, in turn, may reduce the number of Leydig cells, interfere with the testis function during the embryonic period, and damage the development of the genitourinary system.

[Intensive effect of traditional Chinese medicines activating blood to resolve stasis on medicines dredging intestines--influence on peristalsis of small intestine in guinea pigs].

OBJECTIVE: To observe the changes of peristalsis of small intestine in guinea pigs after administration of traditional Chinese medicines activating blood to resolve stasis (Compound Danshen Decoction, CDSD) or/and medicines dredging intestines (Dachengqi Decoction, DCQD), and to explore the synergetic or intensive effect of CDSD on DCQD. METHODS: By means of BL-420 Biological Experimental System, peristalsis of small intestine was recorded and analyzed following administration of DCQD, CDSD or Huoxue Chengqi Decoction (HXCQD, compound of CDSD and DCQD) respectively in different experimental periods. RESULTS: The amplitude and frequency of intestinal peristaltic wave obviously increased following administration of the three decoctions, but HXCQD appeared to be most dominantly. CONCLUSION: The effect of DCQD can be further enhanced by combining use of CDSD, suggesting that the traditional Chinese medicines activating blood to resolve stasis have an intensive effect on medicines dredging intestines.