Consequence of aging at Au/HTM/perovskite interface in triple cation 3D and 2D/3D hybrid perovskite solar cells

Perovskite solar cells (PSCs) expressed great potentials for offering a feasible alternative to conventional photovoltaic technologies. 2D/3D hybrid PSCs, where a 2D capping layer is used over the 3D film to avoid the instability issues associated with perovskite film, have been reported with improved stabilities and high power conversion efficiencies (PCE). However, the profound analysis of the PSCs with prolonged operational lifetime still needs to be described further. Heading towards efficient and long-life PSCs, in-depth insight into the complicated degradation processes and charge dynamics occurring at PSCs' interfaces is vital. In particular, the Au/HTM/perovskite interface got a substantial consideration due to the quest for better charge transfer; and this interface is debatably the trickiest to explain and analyze. In this study, multiple characterization techniques were put together to understand thoroughly the processes that occur at the Au/HTM/perovskite interface. Inquest analysis using current-voltage (I-V), electric field induced second harmonic generation (EFISHG), and impedance spectroscopy (IS) was performed. These techniques showed that the degradation at the Au/HTM/perovskite interface significantly contribute to the increase of charge accumulation and change in impedance value of the PSCs, hence resulting in efficiency fading. The 3D and 2D/3D hybrid cells, with PCEs of 18.87% and 20.21%, respectively, were used in this study, and the analysis was performed over the aging time of 5000 h. Our findings propose that the Au/HTM/perovskite interface engineering is exclusively essential for attaining a reliable performance of the PSCs and provides a new perspective towards the stability enhancement for the perovskite-based future emerging photovoltaic technology.

Enhancement of the carrier mobility of conducting polymers by formation of their graphene composites

Improved carrier mobility and solar cell performance in graphene composites of conducting polymers is demonstrated and analyzed.

Post-laryngectomy voice rehabilitation with a voice prosthesis in a young girl with advanced thyroid cancer

The aim of this report is to evaluate the effects of voice rehabilitation with a voice prosthesis in a young patient with thyroid cancer. A 17-year-old girl underwent voice restoration with a voice prosthesis after laryngectomy to treat thyroid cancer. She completed voice-related questionnaires (the Voice Handicap Index-10 and Voice-Related Quality Of Life Survey) at ages 17 and 21 and underwent phonetic functional evaluation. The sound spectrograms of her phonation using the voice prosthesis showed low frequency sounds without an obvious basic frequency. She was ashamed of her hoarse voice and did not use her voice prosthesis during high school. However, after beginning to work at age 20, she used her voice to communicate in the workplace. At age 21, her questionnaire scores, especially those related to the physical and functional domains, improved compared with those at age 17. Voice restoration with a voice prosthesis is recommended for young patients who undergo laryngectomy for advanced thyroid cancer. The advantages of voice restoration with a voice prosthesis may increase when the patient reaches working age, and it may improve post-laryngectomy quality of life considerably.

Endocytosis of microperoxidase in marginal cells is mainly regulated by RhoA signaling cascade, but not by Rho-associated protein kinase, myosin light-chain kinase and myosin phosphatase

Endocytosis plays an important role in cell function and the activation and propagation of signaling pathways. Signaling occurs on endocytic pathways and signaling endosomes, and endocytosis is subjected to high-order regulation by cellular signaling mechanisms. Marginal cells showed active endocytosis of microperoxidase (MPO) via the clathrin-independent pathway. We examined the signaling pathway that regulates MPO endocytosis in marginal cells using specific inhibitors and activators of signaling molecules. The results showed that pertussis toxin - which inhibits the ribosylation of G-protein-coupled receptor - did not affect MPO endocytosis, but Clostridium botulinum C3 toxin - which induces RhoA inactivation resulting in extracellular-signal-related kinase inactivation - inhibited MPO endocytosis. The main endocytotic pathway of MPO did not depend on the Rho-associated protein kinase molecular switch or actin/myosin motor system, but was mainly regulated by the RhoA signaling cascade.

Endocytosis of MPO in marginal cells is regulated by PKC, protein phosphatase, ERK and PI3-K signaling cascades, but not by PKA and MEK signaling cascades

Endocytosis of marginal cells plays a key role in maintaining the homeostasis of endocytosis and function of the organ of Corti. How the signaling cascade is involved in the regulation of endocytosis is an important issue at present. To investigate the regulation of endocytosis in marginal cells of the stria vascularis by the signaling network, we perfused MPO, an endocytosis tracer, with PMA, OA, staurosporin, PAO, PD98059, SB20580 or wortmannin into the cochlear duct. After 30 min endolymphatic perfusion, the tissues were fixed and the distribution of MPO was examined by electron microscopy. We explored the functions of PKC, RTK, PI3-K, PTP, and PP1/2A in MPO endocytosis and defined the MPO endocytic route. MPO endocytosis was strongly dependent on PKC, ERK, PTP, PP1/2A and PI3-K signaling networks, but not on PKA and MEK signaling networks. The MPO endocytic pathways are clathrin-, GPI-AP-, and caveolae-independent.

Diagnostic value of plasma antidiuretic hormone, electrocochleography, and glycerol test in patients with endolymphatic hydrops

OBJECTIVE

To investigate the relationship between the plasma antidiuretic hormone (p-ADH) level, electrocochleogram (ECoG), and the glycerol test in patients with endolymphatic hydrops (ELH).

PATIENTS AND METHODS

The subjects were 60 patients, including 51 with Ménière's disease (except for cochlear Ménière's disease), 7 with delayed ELH, and 2 with syphilitic ELH. The time period for measurements of the p-ADH level, ECoG and the glycerol test was within 4 weeks.

RESULTS

13 patients showed positive results for all tests. 58 patients showed positive results for at least one of three tests. Only 2 patients showed negative results for all tests.

CONCLUSION

The p-ADH level, ECoG and the glycerol test show different selectivity of ELH detection. It is useful to perform all three tests to diagnose ELH.

Time Course of Vestibular Function Changes of Experimental Endolymphatic Hydrops in Guinea Pigs

<i>Objective:</i> To investigate the relationship between endolymphatic hydrops and vestibular dysfunction. <i>Methods:</i> 20 pigmented guinea pigs were used: 15 for a hydrops group and 5 for a sham group. Endolymphatic hydrops was produced by electrocauterization of the endolymphatic sac on the left ears. In the horizontal vestibuloocular reflex (HVOR) study, HVOR responses were recorded before and 1, 2, and 4 weeks after surgery in 9 animals of the hydrops group and 5 animals of the sham group. HVOR gain under sinusoidal rotation with a maximal head velocity of 45°/s and frequencies of 0.05, 0.1, 0.2, 0.4 and 0.8 Hz was analyzed. In the nystagmus study, spontaneous nystagmus was recorded in all animals of the hydrops and the sham groups for 1 h in the dark and the maximum slow-phase velocity was measured before and 1, 2, 4 weeks after surgery. Morphological changes in the inner ear were measured light microscopically. <i>Results:</i> In the hydrops group, the HVOR gains at all stimulation frequencies seemed to decrease 1 week after surgery and recover 2 or 4 weeks after surgery; however, there were no statistical differences among HVOR gains in any periods after surgery. The incidence of spontaneous nystagmus gradually increased after surgery and the direction and onset showed large variation. The duration of nystagmus was approximately 10 min. The degree of endolymphatic hydrops showed large variation. In the sham group, HVOR gains at all stimulation frequencies showed no statistically different change in any period after surgery. In the sham group, no animal showed spontaneous nystagmus. <i>Conclusion:</i> Experimentally induced endolymphatic hydrops seems to contribute to vestibular dysfunction to some extent. We speculated that when endolymphatic hydrops is progressing, vestibular dysfunction might occur.

Actin filaments and microtubules regulate endocytosis in marginal cells of the stria vascularis

CONCLUSION

Cationized ferritin (CF) was internalized via clathrin-mediated endocytosis. This process depends on clathrin, actin filaments, and microtubules. Microperoxidase (MPO) was internalized via a clathrin- and caveolin-independent endocytic pathway, which was partially dependent on microtubules but independent of clathrin and actin filaments.

OBJECTIVE

We investigated the role of actin filaments and microtubules in the transport of endocytic carrier vesicles (ECVs) from the plasma membrane to the early sorting endosomes, using CF and MPO as tracers.

MATERIALS AND METHODS

Fifty-five guinea pigs were used. The animals were divided into a CF endocytosis group and an MPO endocytosis group. These groups consisted of control, nocodazole-treated, cytochalasin (Cyt D)-treated, Cyt D + nocodazole-treated, and geldanamycin-treated subgroups.

RESULTS

For CF endocytosis, the following results were obtained. In the nocodazole experiment, in which microtubules were disrupted to form monomeric tubulin, the number of ECVs loaded with CF was greatly decreased. In the Cyt D experiment, in which the actin filaments were disrupted to form monomers, the number of ECVs labeled with CF was also greatly decreased. In the geldanamycin experiment, in which clathrin-mediated endocytosis was regulated and actin stress fibers were dissolved, the endocytosis of CF was severely inhibited. For MPO endocytosis, in the nocodazole experiment, the endocytosis of MPO was markedly suppressed.

Expression and immunolocalization of aquaporin-6 (Aqp6) in the rat inner ear

CONCLUSION

Since aquaporin-6 (Aqp6) protein was located in the membrane of intracellular vesicles of the stria vascularis, endolymphatic sac, and vestibule, Aqp6 might be involved in some distinct physiological function of acid-base metabolism and water balance in endolymphatic fluid homeostasis. However, its lack of expression on the plasma membrane indicates that Aqp6 does not have a direct role in water flux via the plasma membrane.

OBJECTIVE

To evaluate the expression and immunolocalization of Aqp6 in the rat inner ear.

MATERIALS AND METHODS

Wistar rats were used. Aqp6 mRNA expression in the rat inner ear was investigated in the vestibulum as well as in the cochlea and endolymphatic sac using the reverse transcription-polymerase chain reaction (RT-PCR) method, and detailed immunolocalization of Aqp6 in the rat inner ear was investigated using immunohistochemical methods including immunofluorescence microscopy and immunoelectron microscopy.

RESULTS

We obtained novel data showing that not just Aqp6 mRNA but also Aqp6 protein is expressed in the cochlea, endolymphatic sac, and vestibule. Immunoelectron microscopic studies revealed that the immunolabelled gold was diffusely seen in the intracellular area of the stria vascularis, endolymphatic sac, and vestibule, but never in the plasma membranes.

Expression of aquaporin1, 3, and 4, NKCC1, and NKCC2 in the human endolymphatic sac

OBJECTIVE

To locate aquaporin (AQP) 1, 3, and 4, Na-K-2Cl cotransporter (NKCC) 1 and 2 in the human endolymphatic sac (ES).

METHODS

A sample of human ES was harvested during the removal of vestibular schwannoma via the translabyrinthine approach. The sample was immediately fixed in 4% paraformaldehyde and embedded in OCT compound. Immunohistochemistry was performed with AQP1, 3, and 4, NKCC1, and NKCC2 polyclonal antibodies.

RESULTS

AQP1, AQP3, and NKCC2 were strongly expressed in the epithelial layer of the ES. AQP4 and NKCC1 were weakly expressed in the epithelial layer of the ES.

CONCLUSIONS

As it is impossible to perform quantitative analysis based on the fluorescence intensity of each immunoreactivity, we have presented the existence of AQP1, 3, and 4, NKCC1, and NKCC2 in the ES. The expression of NKCC1 and 2 indicated that the ES may have both secretory and adsorptive functions to maintain the homeostasis of endolymph.

Presence and regulation of epithelial sodium channels in the marginal cells of stria vascularis

CONCLUSION

This study indicates that epithelial Na(+)-selective channels (ENaC) recycle Na(+) via clathrin-mediated endocytosis in the marginal cells of the stria vascularis and that clathrin-independent endocytosis appeared to be modulated by the amount of Na(+) transported. These results suggest the presence of ENaC in the luminal membrane of marginal cells and that ENaC are an efficient pathway for the uptake of Na(+) from the endolymph.

OBJECTIVE

The ENaC found in many transporting epithelia play a key role in the regulation of salts and water homeostasis, cellular pH, cell volume, and cell function. Both biochemical and physiological approaches have been used to identify, characterize, and quantify this important channel, but its location in the marginal cells of the stria vascularis has not been fully clarified. The aim of this study was to determine the localization and regulation of ENaC.

MATERIALS AND METHODS

Forty healthy female guinea pigs were used: 20 for the control experiment, 10 for the amiloride experiment, and 10 for the aldosterone experiment. We perfused cationized ferritin (CF) and microperoxidase (MPO) as tracers for clathrin-mediated and clathrin-independent endocytosis, respectively, into the cochlear duct. After 30 min of endolymphatic perfusion, the tissues were fixed and CF- and MPO-loaded endosomes within the marginal cell were observed by transmission electron microscopy. The numbers of CF- and MPO-loaded endosomes were compared between the three groups.

RESULTS

In the amiloride group, the numbers of CF- and MPO-loaded endosomes decreased in comparison with the control. In the aldosterone group, the numbers of CF- and MPO-loaded endosomes decreased and increased, respectively. Recently, it has been reported that ENaC are endocytosed via clathrin-mediated endosomes and aldosterone decreases the rate of endocytosis of ENaC. In this study, the results of the aldosterone experiment were consistent with those of recent studies.

Expressions of Aquaporin-2, Vasopressin Type 2 Receptor, Transient Receptor Potential Channel Vanilloid (TRPV)1, and TRPV4 in the Human Endolymphatic Sac

OBJECTIVE

To localize aquaporin (AQP)2, vasopressin type 2 receptor (V2-R), and transient receptor potential channel vanilloid subfamily 1, 4 (TRPV1, TRPV4) in the human endolymphatic sac (ES).

METHODS

Three samples of human ES were sampled during the removal of vestibular schwannoma by way of the translabyrinthine approach. The samples were immediately fixed in 4% paraformaldehyde and embedded in OCT compound; immunohistochemistry was performed with AQP2, V2-R, TRPV1, and TRPV4 polyclonal antibodies.

RESULTS

AQP2, V2-R, TRPV1, and TRPV4 proteins were detected in the epithelial layer of the ES but were not observed in connective tissue around the ES. TRPV1 was also expressed in blood vascular endothelial cells of the connective tissue of ES.

CONCLUSIONS

AQP2, V2-R, and TRPV4 were expressed in the luminal epithelium of human ES. The same characteristic distribution of water and ion channels is seen in the kidney, where a significant amount of fluid is filtrated and resorbed. ES probably plays an active role in the homeostasis of the endolymph.

Endocytosis of microperoxidase in the marginal cells of stria vascularis

OBJECTIVE

Endocytosis has been thought to control entry into the cell and play a crucial role in the development, immune response, neurotransmission, intercellular communication, signal transduction, and cellular and organismal homeostasis. We investigated the basic properties of endocytosis in the marginal cells of stria vascularis (SV) to discuss whether marginal cells have a potential to maintain the endolymph homeostasis.

METHODS

We perfused microperoxidase (MPO), an endocytosis tracer, into the cochlear duct. After 5-60 min of endolymphatic perfusion, the tissues were fixed and the distribution of MPO within the marginal cell was observed by transmission electron microscopy.

RESULTS

Endocytosis started already at 5 min after MPO perfusion. Small MPO-loaded endosomes were observed up to 30 min after MPO perfusion. The small tubulovesicular endosomes and the plasma membrane invagination were not decorated by an electron dense bristle structure. After endocytosis, MPO labeled preendosomes were quickly transported to the large vacuolar endosomes that connected with tubular endosomes. At 60 min after MPO perfusion, MPO-loaded large vesicles that have small vesicles in the lumen were observed.

CONCLUSION

The time-course of MPO-loaded endosomes was similar to that of CF-loaded endosomes in the marginal cells of SV. The strial marginal cells have vigorous endocytotic activity both in clathrin-independent and clathrin-dependent endocytosis. This high activity of endocytosis in SV seems to be needed to maintain the homeostasis of endolymph via membranous channels and/or receptors regulations.

Antidiuretic Hormone and Osmolality in Isosorbide Therapy and Glycerol Test

Changes in plasma antidiuretic hormone (p-ADH) and plasma osmolality (p-Osm) levels were studied in 63 patients with Ménière's disease before and after isosorbide administration and a glycerol test. Increments in both p-ADH and p-Osm levels were observed after isosorbide administration and the glycerol test. The p-ADH secretion appeared to be secondarily stimulated by an increase in the p-Osm level. This p-ADH level increase affects cochlear fluid homeostasis. Based on these results, we must consider both the p-Osm and p-ADH levels when treating patients with Ménière's disease by osmotic diuretics.

A comparison of dehydration effects of V2-antagonist (OPC-31260) on the inner ear between systemic and round window applications

V2-antagonist (OPC-31260 (OPC)) application to the scala tympani reduced endolymphatic hydrops. In the present study, we investigated whether systemic administration or local infusion via the round window (RW application) of OPC would be more suitable for clinical use. In Experiment 1, the increase ratios of the cross-sectional area of the scala media of experimentally induced endolymphatic hydrops were quantitatively assessed among four groups of non-OPC application, RW application of xanthan gum, systemic application of OPC and RW application of OPC. In Experiment 2, the effects of systemic and RW applications of OPC on plasma vasopressin (p-VP) concentrations and plasma osmolality (p-OSM) were investigated. In Experiment 3, endocochlear DC potential (EP) was measured in guinea pigs with the RW application of OPC. Electron microscopic observations of the stria vascularis and the hair cells were also made. Both systemic and RW applications of OPC significantly reduced endolymphatic hydrops. However, systemic application resulted in the distension of the Reissner's membrane in the non-operated ear, which seemed to be caused by elevated p-VP levels resulting from the systemic application of OPC. In contrast, RW application of OPC produced no apparent toxic effects in the inner ear, as indicated electrophysiological or morphological changes. Thus, drug delivery via the round window is more useful for the clinical application of OPC for medical decompression.

Effect of lesion level on the orthotic gait performance in individuals with complete paraplegia

STUDY DESIGN

Cross-sectional, experimental research.

OBJECTIVES

To clarify the effect of lesion level on cardio-respiratory responses and biomechanical characteristics of walking with a reciprocating gait orthosis in complete paraplegia with spinal cord injury (SCI).

SETTING

National Rehabilitation Center for Persons with Disabilities, Japan.

METHODS

Ten SCI individuals (age: 20-34 years, injured level: Th5-12) who experienced orthotic gait training at least for 10 weeks participated in two experiments: (1) measurement of the cardiorespiratory responses during 20 min of orthotic gait exercise; and (2) three-dimensional motion analysis and ground reaction force measurement using the VICON system. We calculated the following parameters: pulmonary ventilation, oxygen consumption (VO(2)), heart rate (HR), gait speed, cadence, stride length, crutch force (CF), hip range of motion (ROM), and hip angular velocity (VEL). Further, energy consumption and energy cost were calculated using the steady-state value of VO(2) and gait speed.

RESULTS

The steady-state value of the VO(2) (18.2 +/- 3.80 ml/kg) and HR (133.0 +/- 21.63 b/min) tended to be larger in higher thoracic SCI subjects. There were strong positive correlations between the lesion level and walking speed (r = 0.74), energy cost (r = 0.85), and hip ROM (r = 0.78). On the other hand, negative correlation between the lesion level and peak CF (r = -0.78) was clarified.

CONCLUSIONS

The physiological intensity of the orthotic gait strongly depended on the level of lesion. It seems likely that a limited hip range of motion and excess upper limb load result in the low energy cost of orthotic gait for the higher thoracic level of paraplegic patients.

[Managing small pulmonary nodules in head and neck malignant tumors]

The recent increase in the use of helical CT has produced a higher detection rate of small pulmonary nodules than in conventional CT application, and has presented a serious problem in their treatment. We carried out a retrospective study to identify a clinical standard in the management of those nodules in head and neck malignant tumors. The subjects were 108 in-and out patients (87 men and 21 women) with head and neck malignant tumors who received radiation therapy in our university hospital between 2003 and 2004 (ages ranging from 25 to 93 years; mean, 66 years). Helical CT of the chest was applied to 92 patients of the 108 (85%). We determined small pulmonary nodules as round nodules 5 mm or more and less than 1 cm in diameter, and observed them in 14 of the 92 (15%). Firstly, we compared nodule growth by dividing the patients into 2 groups. The nodules grew in 2 of 7 patients of Group I, where chemotherapy was not done or where chemotherapy was not effective on the primary tumor, and in 3 of 7 patients of Group II, where chemotherapy was effective on the primary tumor. Secondly, disregarding the effects of chemotherapy, we analyzed nodule growth: the nodules grew in 5 of the 14 patients (36%). Those small pulmonary nodules were all pulmonary metastases. When small pulmonary nodules are detected by helical CT, accompanying malignant tumors of the head and neck, and bearing in mind the probability of their growth of at least 36%, we should therefore follow them up carefully.

Stable isotope-labeling studies on the oxidative coupling of caffeic acid via o-quinone

The formation of ortho-quinone from ortho-diphenol is a key step in its dimerization. An NMR analysis of the oxidation of 3,4-dihydroxycinnamic acid (caffeic acid) by NaIO4 revealed the formation of 3-(3',4'-dioxo-1',5'-cyclohexadienyl) propenoic acid (o-quinone) prior to the formation of furofuran-type lignan 4,8-exo-bis (3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3.3.0]octane-2,6-dione. Both electrolytic and enzymatic oxidation of caffeic acid also generated o-quinone. The yields of o-quinone from caffeic acid were quantified by NMR and HPLC analyses. A stable isotope-labeling study of the formation of lignans directly proved the random radical coupling of semiquinone radicals formed from a set of caffeic acid and o-quinone.