Intermolecular Interactions between Cysteine and Aromatic Amino Acids with a Phenyl Moiety in the DNA-Binding Domain of Heat Shock Factor 1 Regulate Thermal Stress-Induced Trimerization.

In this study, we investigated the trimerization mechanism and structure of heat shock factor 1 (HSF1) using western blotting, tryptophan (Trp) fluorescence spectroscopy, and molecular modeling. First, we examined the DNA-binding domains of human (Homo sapiens), goldfish (Carassius auratus), and walleye pollock (Gadus chalcogrammus) HSF1s by mutating key residues (36 and 103) that are thought to directly affect trimer formation. Human, goldfish, and walleye pollock HSF1s contain cysteine at residue 36 but cysteine (C), tyrosine (Y), and phenylalanine (F), respectively, at residue 103. The optimal trimerization temperatures for the wild-type HSF1s of each species were found to be 42, 37, and 20 °C, respectively. Interestingly, a mutation experiment revealed that trimerization occurred at 42 °C when residue 103 was cysteine, at 37 °C when it was tyrosine, and at 20 °C when it was phenylalanine, regardless of the species. In addition, it was confirmed that when residue 103 of the three species was mutated to alanine, trimerization did not occur. This suggests that in addition to trimerization via disulfide bond formation between the cysteine residues in human HSF1, trimerization can also occur via the formation of a different type of bond between cysteine and aromatic ring residues such as tyrosine and phenylalanine. We also confirmed that at least one cysteine is required for the trimerization of HSF1s, regardless of its position (residue 36 or 103). Additionally, it was shown that the trimer formation temperature is related to growth and survival in fish.

pH Dependence of HSF1 trimerization is shaped by intramolecular interactions.

Heat shock factor 1 (HSF1) primarily regulates various cellular stress responses. Previous studies have shown that low pH within the physiological range directly activates HSF1 function in vitro. However, the detailed molecular mechanisms remain unclear. This study proposes a molecular mechanism based on the trimerization behavior of HSF1 at different pH values. Extensive mutagenesis of human and goldfish HSF1 revealed that the optimal pH for trimerization depended on the identity of residue 103. In particular, when residue 103 was occupied by tyrosine, a significant increase in the optimal pH was observed, regardless of the rest of the sequence. This behavior can be explained by the protonation state of the neighboring histidine residues, His101 and His110. Residue 103 plays a key role in trimerization by forming disulfide or non-covalent bonds with Cys36. If tyrosine resides at residue 103 in an acidic environment, its electrostatic interactions with positively charged histidine residues prevent effective trimerization. His101 and His110 are neutralized at a higher pH, which releases Tyr103 to interact with Cys36 and drives the effective trimerization of HSF1. This study showed that the protonation state of a histidine residue can regulate the intramolecular interactions, which consequently leads to a drastic change in the oligomerization behavior of the entire protein.

Should the diameter of the proximal femoral nail be large enough to fill the canal in the treatment of intertrochanteric femoral fracture in patients over fifty?

PURPOSE: Many studies have been conducted to evaluate the effects of nail shape, design, or length on the treatment of intertrochanteric fractures. However, the clinical implications of the nail diameter remain unclear. METHODS: This study was conducted with 191 patients aged ≥ 50 years with unilateral intertrochanteric fractures treated with the same type of short cephalomedullary nail and followed for at least one year. We recorded the reduction type, tip-apex distance, cortical contact of the nail, and nail/canal diameter ratio (NCR) just distal to the locking screw. The effects of nail diameter on the clinical results were evaluated. RESULTS: The average NCR was 68.7. The average union time was 4.78 months. Delayed union or nonunion was seen in 17 patients. Eight patients underwent additional surgery. The mean change in the modified Koval activity score was -0.84. The NCR did not significantly affect the clinical results. Comparisons of cases with NCRs above and below the average and the average - 1 standard deviation revealed no significant difference. The clinical outcome was not related to any variable associated with the nail diameter. CONCLUSION: With this specific proximal femoral nail, a small diameter relative to that of the femoral canal had no adverse effect on the union of osteoporotic intertrochanteric fractures, even in patients with unstable fractures and those who had unsatisfactory reductions.

Neuromyelitis optica spectrum disorder with herpes simplex viral infection presenting with syndrome of inappropriate antidiuretic hormone: A case report.

RATIONALE: Neuromyelitis optica spectrum disorder (NMOSD) is a demyelinating disease that causes lesions in areas with abundant aquaporin-4 (AQP4) channels, including the hypothalamus. Hypothalamic lesions can disrupt antidiuretic hormone regulation, resulting in hyponatremia due to syndrome of inappropriate antidiuretic hormone (SIADH). Various factors can trigger NMOSD, including viral infections. We report the case of a young female patient who presented with hyponatremia due to SIADH and was found to have bilateral hypothalamic lesions along with positive serum herpes simplex virus immunoglobulin M. PATIENT CONCERNS: An 18-year old female patient presented with fever and nausea that had persisted for 5 days. Three days after hospitalization, the patient complained of blurred vision, hiccups, and excessive daytime sleepiness. DIAGNOSIS: The patient hyponatremia was attributed to SIADH. Magnetic resonance imaging revealed bilateral lesions in the hypothalamus, and serum laboratory tests were positive for herpes simplex virus immunoglobulin M. On the 15th day of admission, the anti-AQP4 antibody test result was positive, leading to the diagnosis of NMOSD. INTERVENTIONS: On the initial suspicion of herpes encephalitis, treatment with acyclovir was initiated. However, upon the confirmation of after anti-AQP4 antibody, the patient was additionally treated with a high-dose intravenous steroid for 5 days. OUTCOMES: The patient fever, nausea, visual disturbances, and other complaints improved within 1 week of initiating steroid treatment. LESSONS: In young patients presenting with hyponatremia and suspected SIADH accompanied by neurological abnormalities, it is crucial to differentiate central nervous system diseases, including NMOSD, which can involve lesions in AQP4-abundant areas, such as the hypothalamus.

Fabrication and properties of Sn(iv) porphyrin-linked porous organic polymer for environmental applications.

A robust porous organic polymer cross-linked by Sn(iv) porphyrin (SnPOP) was fabricated by reacting trans-dihydroxo-[5,15,10,20-tetrakis(phenyl)porphyrinato]tin(iv) (SnP) with fluorinated polyimide (FPI) via sol-gel formation, followed by supercritical CO2 drying. The structural and porous properties of SnPOP were characterized using FT-IR, UV-vis, and fluorescence spectroscopies, along with field-emission scanning electron microscopy and gas sorption experiments. The reaction between the SnP's oxophilic Sn(iv) center and FPI's carboxylic acid moiety resulted in a controllable cross-linked porous texture. This material features the desirable physical properties of porphyrin and exhibits mesoporous structures with a relatively high surface area. SnPOP is thermally stable at temperatures up to 600 °C and highly resistant to boiling water, strong acids, and bases, owing to its assembly via formation of covalent bonds instead of typically weaker hydrogen bonds. The modified chemical and morphological structures of SnPOP showed an impressive CO2 uptake capacity of 58.48 mg g-1 at 273 K, with a preference for CO2 over N2. SnPOP showed significant efficiency in removing pollutant dyes, such as methylene blue and methyl orange, from dye-contaminated water. Additionally, SnPOP was a photocatalyst for fabricating silver nanoparticles of regular shape and size. All these properties make SnPOP a potential candidate for environmental applications like pollutant removal, gas storage, and separation.

Layer-resolved release of epitaxial layers in III-V heterostructure via a buffer-free mechanical separation technique.

Layer-release techniques for producing freestanding III-V epitaxial layers have been actively developed for heterointegration of single-crystalline compound semiconductors with Si platforms. However, for the release of target epitaxial layers from III-V heterostructures, it is required to embed a mechanically or chemically weak sacrificial buffer beneath the target layers. This requirement severely limits the scope of processable materials and their epi-structures and makes the growth and layer-release process complicated. Here, we report that epitaxial layers in commonly used III-V heterostructures can be precisely released with an atomic-scale surface flatness via a buffer-free separation technique. This result shows that heteroepitaxial interfaces of a normal lattice-matched III-V heterostructure can be mechanically separated without a sacrificial buffer and the target interface for separation can be selectively determined by adjusting process conditions. This technique of selective release of epitaxial layers in III-V heterostructures will provide high fabrication flexibility in compound semiconductor technology.

Simultaneous Extraction of the Grain Size, Single-Crystalline Grain Sheet Resistance, and Grain Boundary Resistivity of Polycrystalline Monolayer Graphene.

The electrical properties of polycrystalline graphene grown by chemical vapor deposition (CVD) are determined by grain-related parameters-average grain size, single-crystalline grain sheet resistance, and grain boundary (GB) resistivity. However, extracting these parameters still remains challenging because of the difficulty in observing graphene GBs and decoupling the grain sheet resistance and GB resistivity. In this work, we developed an electrical characterization method that can extract the average grain size, single-crystalline grain sheet resistance, and GB resistivity simultaneously. We observed that the material property, graphene sheet resistance, could depend on the device dimension and developed an analytical resistance model based on the cumulative distribution function of the gamma distribution, explaining the effect of the GB density and distribution in the graphene channel. We applied this model to CVD-grown monolayer graphene by characterizing transmission-line model patterns and simultaneously extracted the average grain size (~5.95 µm), single-crystalline grain sheet resistance (~321 Ω/sq), and GB resistivity (~18.16 kΩ-µm) of the CVD-graphene layer. The extracted values agreed well with those obtained from scanning electron microscopy images of ultraviolet/ozone-treated GBs and the electrical characterization of graphene devices with sub-micrometer channel lengths.

Automatic Multi-Stage Cold Forging of an SUS304 Ball-Stud with a Hexagonal Hole at One End.

SUS304 stainless steel is characterized by combined tensile and compression testing, with an emphasis on flow stress at higher strain and temperature. The plastic deformation behavior of SUS304 from room temperature to 400 °C is examined and a general approach is used to express flow stress as a closed-form function of strain, strain rate, and temperature; this is optimal when the strain is high, especially during automatic multi-stage cold forging. The fitted flow stress is subjected to elastothermoviscoplastic finite element analysis (FEA) of an automatic multi-stage cold forging process for an SUS304 ball-stud. The importance of the thermal effect during cold forging, in terms of high material strength and good strain-hardening, is revealed by comparing the forming load, die wear and die stress predictions of non-isothermal and isothermal FEAs. The experiments have shown that the predictions of isothermal FEA are not feasible because of the high predicted effective stress on the weakest part of the die.

Effect of Graphene Doping Level near the Metal Contact Region on Electrical and Photoresponse Characteristics of Graphene Photodetector.

Graphene-metal contact is crucial to fabricate high-performance graphene photodetectors since the external quantum efficiency (EQE) of the photodetector depends on the contact properties, and the influence of the contact properties is particularly dominant in short channel devices for high-speed applications. Moreover, junction properties between the channel graphene and graphene near the contact are also important to analyze the photoresponse because the built-in electric field in the junction determines the EQE of the photodetector. In this study, we investigated a relation between the photoresponse and the built-in electric field induced from the doping level difference in the junction between the channel graphene and graphene near the contact. The photoresponse could be enhanced with a high junction barrier height that is tuned by the doping level difference. In addition, we observed that the improved electrical characteristics of channel graphene do not guarantee the enhancement of the photoresponse characteristics of graphene photodetectors.

Fully Differential Touch Screen Controller with Wide Input Dynamic Range for Thin Displays.

As today's smartphone displays become thinner, the coupling capacitance between the display electrodes and touch screen panel (TSP) electrodes is increasing significantly. The increased capacitance easily introduces time-varying display signals into the TSP, deteriorating the touch performance. In this research, we demonstrate that the maximum peak display noise in the time domain is approximately 30% of the maximum voltage difference of the display grayscale through analysis of the structure and operation of displays. Then, to mitigate display noise, we propose a circuit solution that uses a fully differential charge amplifier with an input dynamic range wider than the maximum peak of the display noise. A test chip was fabricated using a 0.35 µm CMOS process and achieved a signal-to-noise ratio of 41 dB for a 6-mm-diameter metal pillar touch when display pulses with 5-V swing were driven at 100 kHz.

GaN-Based Ultraviolet Passive Pixel Sensor on Silicon (111) Substrate.

The fabrication of a single pixel sensor, which is a fundamental element device for the fabrication of an array-type pixel sensor, requires an integration technique of a photodetector and transistor on a wafer. In conventional GaN-based ultraviolet (UV) imaging devices, a hybrid-type integration process is typically utilized, which involves a backside substrate etching and a wafer-to-wafer bonding process. In this work, we developed a GaN-based UV passive pixel sensor (PPS) by integrating a GaN metal-semiconductor-metal (MSM) UV photodetector and a Schottky-barrier (SB) metal-oxide-semiconductor field-effect transistor (MOSFET) on an epitaxially grown GaN layer on silicon substrate. An MSM-type UV sensor had a low dark current density of 3.3 × 10-7 A/cm² and a high UV/visible rejection ratio of 10³. The GaN SB-MOSFET showed a normally-off operation and exhibited a maximum drain current of 0.5 mA/mm and a maximum transconductance of 30 µS/mm with a threshold voltage of 4.5 V. The UV PPS showed good UV response and a high dark-to-photo contrast ratio of 10³ under irradiation of 365-nm UV. This integration technique will provide one possible way for a monolithic integration of the GaN-based optoelectronic devices.

Mutual Capacitive Sensing Touch Screen Controller for Ultrathin Display with Extended Signal Passband Using Negative Capacitance.

Flexible and thin displays for smart devices have a large coupling capacitance between the sensor electrode of the touch screen panel (TSP) and the display electrode. This increased coupling capacitance limits the signal passband to less than 100 kHz, resulting in a significant reduction in the received signal, with a driving frequency of several hundred kilohertz used for noise avoidance. To overcome this problem, we reduced the effective capacitance at the analog front-end by connecting a circuit with a negative capacitance in parallel with the coupling capacitance of the TSP. In addition, the in-phase and quadrature demodulation scheme was used to address the phase fluctuation between the signal and the clock during demodulation. We fabricated a test chip using the 0.35 µm CMOS process and obtained a signal-to-noise ratio of 43.2 dB for a 6 mm diameter metal pillar touch input.

Optimized poly(methyl methacrylate)-mediated graphene-transfer process for fabrication of high-quality graphene layer.

Graphene grown on a copper (Cu) substrate by chemical vapor deposition (CVD) is typically required to be transferred to another substrate for the fabrication of various electrical devices. PMMA-mediated wet process is the most widely used method for CVD-graphene-transfer. However, PMMA residue and wrinkles that inevitably remain on the graphene surface during the transfer process are critical issues degrading the electrical properties of graphene. In this paper, we report on a PMMA-mediated graphene-transfer method that can effectively reduce the density and size of the PMMA residue and the height of wrinkles on the transferred graphene layer. We found out that acetic acid is the most effective PMMA stripper among the typically used solutions to remove the PMMA residue. In addition, we observed that an optimized annealing process can reduce the height of the wrinkles on the transferred graphene layer without degrading the graphene quality. The effects of the suggested wet transfer process were also investigated by evaluating the electrical properties of field-effect transistors fabricated on the transferred graphene layer. The results of this work will contribute to the development of fabrication processes for high-quality graphene devices, given that the transfer of graphene from the Cu substrate is essential process to the application of CVD-graphene.

Analysis of Multi-Level Simultaneous Driving Technique for Capacitive Touch Sensors.

The signal-to-noise ratio (SNR) and driving levels of capacitive touch sensors determine the applicability of these sensors to thinner displays and sensor-integrated modules. The simultaneous driving technique has been widely applied to capacitive touch sensors to cope with various types of environmental noise. A Hadamard matrix has been used to determine the driving code and multiplex capacitive signals required to increase the SNR and responsivity of touch sensors. Using multi-level Hadamard matrices, a new driving technique for sensing concurrent capacitive elements across multiple rows of a touch panel was developed. The technique provides more effective design choices than the existing bipolar driving method by supporting a variety of orders of matrices and regular capacity. The required TX voltage can be reduced by applying the Kronecker product for higher orders of simultaneous driving. A system model is presented for multiplexing capacitive signals to extract the SNR of the existing Hadamard matrices as well as one of the proposed multi-level sequences. In addition, the corresponding multi-level drivers and receivers were implemented to verify the theoretical expectations and simulation results of the proposed technique.

Selectively Enhanced UV-A Photoresponsivity of a GaN MSM UV Photodetector with a Step-Graded AlxGa1-xN Buffer Layer.

The UV-to-visible rejection ratio is one of the important figure of merits of GaN-based UV photodetectors. For cost-effectiveness and large-scale fabrication of GaN devices, we tried to grow a GaN epitaxial layer on silicon substrate with complicated buffer layers for a stress-release. It is known that the structure of the buffer layers affects the performance of devices fabricated on the GaN epitaxial layers. In this study, we show that the design of a buffer layer structure can make effect on the UV-to-visible rejection ratio of GaN UV photodetectors. The GaN photodetector fabricated on GaN-on-silicon substrate with a step-graded AlxGa-xN buffer layer has a highly-selective photoresponse at 365-nm wavelength. The UV-to-visible rejection ratio of the GaN UV photodetector with the step-graded AlxGa1-xN buffer layer was an order-of-magnitude higher than that of a photodetector with a conventional GaN/AlN multi buffer layer. The maximum photoresponsivity was as high as 5 × 10-² A/W. This result implies that the design of buffer layer is important for photoresponse characteristics of GaN UV photodetectors as well as the crystal quality of the GaN epitaxial layers.

Posterior shoulder dislocation with ipsilateral proximal humerus type 2 physeal fracture: case report.

In pediatric patients, proximal humeral physeal fractures are uncommon injuries compared with distal physeal fractures. Usually, the growth plate is the most vulnerable site of fracture in the proximal humerus. Proximal humeral physeal fractures accompanying posterior shoulder dislocation are very rare. There are few recent reports on the combination of glenohumeral dislocation and proximal humerus fractures. Here, we describe a case of posterior shoulder dislocation with ipsilateral proximal humerus type 2 physeal fracture in a 9-year-old boy. We treated the patient by closed reduction and percutaneous pinning under general anesthesia.

Serial Changes in Sexual Function Following Holmium Laser Enucleation of the Prostate: A Short-term Follow-up Study.

PURPOSE: To evaluate the serial changes in sexual function in the short-term period after holmium laser enucleation of the prostate (HoLEP) for benign prostatic hyperplasia (BPH) and to investigate whether a change in each domain of the International Index of Erectile Function (IIEF) is associated with improvement of micturition. MATERIALS AND METHODS: Thirty-eight potent men who underwent HoLEP and in whom complete 12-month follow-up data on the IIEF were available were included in this retrospective study. All patients underwent a baseline evaluation for BPH. The surgical outcome was evaluated at 1, 3, 6, and 12 months postoperatively by use of the International Prostate Symptom Score, IIEF, and uroflowmetry. RESULTS: The mean age and body mass index of the patients was 64.5±6.2 years and 24.2±2.6 kg/m(2), respectively. Mean total prostate volume and transitional zone volume were 48.8±18.8 ml and 24.2±16.1 ml, respectively. Most IIEF domain scores showed a slight decrease at 1, 3, and 6 months after surgery but recovered to the baseline or showed a marginal but nonsignificant increase at 12 months postoperatively compared with baseline. Orgasmic function and the overall sexual satisfaction domain score remained slightly reduced up to 12 months postoperatively. There was no significant correlation between improvement of micturition and change in sexual function throughout the follow-up period after surgery. CONCLUSIONS: Although HoLEP achieves significant improvements in micturition, overall sexual function decreases slightly in the early postoperative period, but recovers to the baseline at 12 months postoperatively. Our data suggest that changes in sexual function after HoLEP are not associated with improvement of micturition.

Significance of clopidogrel resistance related to the stent-assisted angioplasty in patients with atherosclerotic cerebrovascular disease.

OBJECTIVE: To evaluate the prevalence and risk factors of clopidogrel resistance, and association between thromboembolic complications and clopidogrel resistance in patient with stent-assisted angioplasty for atherosclerotic cerebrovascular disease. METHODS: Between September 2006 and June 2008, clopidogrel resistance test was performed on 41 patients who underwent stent-assisted angioplasty for atherosclerotic cerebrovascular disease. It was performed before drug administration and about 12 hours after drug administration (loading dose : 300 mg, maintain dose : 75 mg). Two patients were excluded, and 41 patients were included (mean : 67.59±7.10 years, age range : 41-79). Among 41 patients, 18 patients had intracranial lesions, and 23 had extracranial lesions. We evaluated the prevalence, risk factors and complications related to clopidogrel resistance. RESULTS: Twenty-one patients (51.2%) showed clopidogrel resistance [intracranial : 10 patients (55.6%), extracranial : 11 patients (47.8%)] and no clopidogrel resistance was seen in 20 patients. Hypercholesterolemia was an indepedent risk factor of clopidogrel resistance. Stent-assisted angioplasty was technically successful in all patients, but acute in-stent thrombosis occurred in 5 patients with intracranial lesions (4 patients with clopidogrel resistance and 1 without clopidogrel resistance). Acute thrombi were completely lysed after intra-arterial infusion of abciximab. CONCLUSION: There was relatively high prevalence of clopidogrel resistance in patients with atherosclerotic cerebrovascular disease. Hypercholesterolemia was an independent predictive factor of clopidogrel resistance. Acute in-stent thrombosis was more frequently seen in the clopidogrel resistant group. Therefore, clopidogrel resistance test should be performed to avoid thromboembolic complications related to stent-assisted angioplasty for atherosclerotic cerebrovascular disease, especially patients with hypercholeterolemia and intracranial lesion.

Modified vaporization-resection for photoselective vaporization of the prostate using a GreenLight high-performance system 120-W Laser: the Seoul technique.

OBJECTIVES: The most popular technique of photoselective vaporization of the prostate (PVP) for benign prostatic hyperplasia (BPH) involves vaporization only. We developed a modified vaporization-resection technique that consists of vaporizing a prostate along outlined margins and retrieving the wedge-shaped prostate tissue. We report the operative procedure and clinical outcomes of our technique with the GreenLight high performance system (HPS). METHODS: A total of 104 patients with a prostate volume greater than 40 mL who underwent PVP were included in this retrospective study. Forty patients were treated with the vaporization-only technique (Group non-S) and 64 patients with the Seoul technique (group S). The clinical outcomes were assessed at 1, 3, 6, and 12 months postoperatively using the International Prostate Symptom Score (IPSS), quality of life (QoL) score, maximum flow rate (Q(max.)), and postvoid residual urine volume (PVR). RESULTS: The Q(max.), PVR, IPSS, and QoL scores improved significantly from 1 to 12 months after the PVP compared with the baseline in both groups (P <.05). In the S group, the volume reduction of the prostate per operative time, lasing time, and laser energy were significantly smaller than in the non-S group (P <.05). In general, the overall complication rates were low in the 2 groups. Two patients were found to have prostate cancer on pathology. CONCLUSIONS: The Seoul technique for PVP showed good short-term efficacy and safety for the treatment of BPH. With this technique, we can conserve on the operative time, lasing time, and energy, and obtain prostatic tissue for pathologic evaluation.

Changes in nocturia after photoselective vaporization of the prostate for patients with benign prostatic hyperplasia.

PURPOSE: To investigate changes in nocturia and predictive factors for improvement after photoselective vaporization of the prostate (PVP) for patients with benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: A total of 103 patients who complained of nocturia of >/=2 times per night on baseline frequency-volume chart (FVC) and who underwent PVP were included in this retrospective study. All patients underwent a preoperative evaluation for BPH including multichannel video urodynamics. The efficacy of the PVP was evaluated at 1, 3, 6, and 12 months postoperatively by use of the International Prostate Symptom Score (IPSS) and FVC. Subjective and objective improvement of nocturia were defined as a reduction of >/=50% in nocturnal frequency compared with baseline on the IPSS and FVC, respectively. RESULTS: As shown by the IPSS and FVC, nocturia was significantly reduced starting from 1 month after PVP. The percentage of patients with improvement in nocturia was 20.0%, 20.7%, 36.2%, and 27.9% on the IPSS, and 30.1%, 48.6%, 52.2%, and 54.5% on the FVC at 1, 3, 6, and 12 months after PVP, respectively. None of the baseline parameters, including the presence or absence of nocturnal polyuria (NPU), reduced nocturnal bladder capacity (NBC), and detrusor overactivity (DO), were associated with improvement of nocturia. CONCLUSIONS: Nocturnal frequency was significantly reduced from the early postoperative period after PVP. Improvement in nocturia after PVP was not affected by baseline nocturnal frequency, the presence or absence of preoperative NPU, or reduced NBC or DO on baseline urodynamics.