Analysis of veering during gait in blind individuals.

BACKGROUND: Veering occurs during blind walking, which causes individuals to deviate from crosswalks or fall off platforms. Despite being linked to static postural control, the relationship between veering and gait function (gait variability and plantar pressure), which is presumed to be related to dynamic postural control, has yet to be fully understood. RESEARCH QUESTION: How do gait variability and plantar pressure affect veering? METHODS: This experiment involved a walking task in which 11 blind adults were instructed to walk along a straight path using a white cane. We measured the veering values and analyzed the relationship between gait variability and plantar pressure. RESULTS: One participant with a particularly severe veering tendency was excluded from the analysis. Based on the veering characteristics of the participants, the walking trajectories were classified as veering to the left (14 trials) or the right (14 trials) sides. Correlation analysis showed no significant correlation between the veering value and gait variability (vertical, lateral, and anterior-posterior). Plantar pressure (the ball of the fifth toe and the total) was significantly negatively correlate with the veering value. In contrast, the plantar pressure results for the participant who was excluded showed a different characteristic. SIGNIFICANCE: We hypothesized that blind individuals would exhibit dynamic postural control to stay on a straight path by increasing the plantar pressure on the ball of the fifth toe and the total pressure on the opposite foot when veering occurs. However, this adaptation was not observed in a blind individual with severe veering tendencies.

Chronic Clinical Findings after Rheocarna® Therapy in a Chronic Limb-threatening Ischemia Patient with Inframalleolar Lesions: A Case Report.

An 87-year-old man was referred to our hospital for non-healing ulcers on the right third, fourth, and fifth toes. The patient was diagnosed with chronic limb-threatening ischemia. Pre-treatment angiography of the right lower extremity revealed inframalleolar lesions. We failed to perform endovascular treatment because of severe calcification. Therefore, we treated the patient with a novel low-density lipoprotein apheresis device (Rheocarna®; Kaneka Corporation, Osaka, Japan). Angiography performed four days after therapy revealed significant improvement in microcirculation. One year after therapy, he managed to avoid major amputation and achieve wound healing. In addition, angiography revealed that the microcirculation was maintained.

Association among craniofacial morphology, ethnicity, and risk of pediatric sleep-related breathing disorders: A multicenter study.

INTRODUCTION: Craniofacial morphology and ethnicity may be risk factors for sleep-related breathing disorder (SRBD) in children but have not yet been assessed in an international multicenter study. The objectives of this study were to assess the association among craniofacial features, self-reported ethnicity, and risk of SRBD in children undergoing orthodontic treatment. METHODS: Children aged 5-18 years who presented for orthodontic evaluation were enrolled in the United States, South Africa, South Korea, Saudi Arabia, and Japan. The risk of SRBD was defined as answering ≥0.33 positive responses to the Pediatric Sleep Questionnaire. Craniofacial features included measurements in sagittal and vertical dimensions to evaluate the cranial base, maxillomandibular and dental relationships, and nasopharyngeal airway dimensions. Logistic regression was performed to assess the association among craniofacial features, ethnicity, age, body mass index, and risk of SRBD. RESULTS: Data were obtained from 602 patients from 5 sites. A total of 76 patients (12.6%) had a risk of SRBD. The mean age was 12.5 years. Male gender (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.0-3.4; P = 0.041), Middle Eastern ethnicity (OR, 10.2; 95% CI, 4.1-25.4; P = 0.001), body mass index (OR, 1.1; 95% CI, 1.04-1.10; P = 0.001), gonial angle (OR, 0.91; 95% CI, 0.85-0.98; P = 0.011), and inferiorly positioned hyoid (OR, 1.1; 95% CI, 1.0-1.2; P = 0.002) were significantly associated with the risk of SRBD. CONCLUSIONS: In an ambidirectional cohort study across 5 sites, male gender, Middle Eastern ethnicity, body mass index, gonial angle, and inferiorly positioned hyoid were associated with the risk of SRBD in children undergoing orthodontic treatment.

Thermus thermophilus polyploid cells directly imaged by X-ray laser diffraction.

Thermus thermophilus is reportedly polyploid and carries four to five identical genome copies per cell, based on molecular biological experiments. To directly detect polyploidy in this bacterium, we performed live cell imaging by X-ray free-electron laser (XFEL) diffraction and observed its internal structures. The use of femtosecond XFEL pulses enables snapshots of live, undamaged cells. For successful XFEL imaging, we developed a bacterial culture method using a starch- and casein-rich medium that produces a predominance of rod-shaped cells shorter than the focused XFEL beam size, which is slightly smaller than 2 µm. When cultured in the developed medium, the length of T. thermophilus cells, which is typically ~4 µm, was less than half its usual length. We placed living cells in a micro-liquid enclosure array and successively exposed each enclosure to a single XFEL pulse. A cell image was successfully obtained by the coherent diffractive imaging technique with iterative phase retrieval calculations. The reconstructed cell image revealed five peaks, which are most likely to be nucleoids, arranged in a row in the polyploid cell without gaps. This study demonstrates that XFELs offer a novel approach for visualizing the internal nanostructures of living, micrometer-sized, polyploid bacterial cells.

Diagnostic accuracy of point-of-care ultrasound for shock: a systematic review and meta-analysis.

BACKGROUND: Circulatory failure is classified into four types of shock (obstructive, cardiogenic, distributive, and hypovolemic) that must be distinguished as each requires a different treatment. Point-of-care ultrasound (POCUS) is widely used in clinical practice for acute conditions, and several diagnostic protocols using POCUS for shock have been developed. This study aimed to evaluate the diagnostic accuracy of POCUS in identifying the etiology of shock. METHODS: We conducted a systematic literature search of MEDLINE, Cochrane Central Register of Controlled Trials, Embase, Web of Science, Clinicaltrial.gov, European Union Clinical Trials Register, WHO International Clinical Trials Registry Platform, and University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) until June 15, 2022. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and assessed study quality using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Meta-analysis was conducted to pool the diagnostic accuracy of POCUS for each type of shock. The study protocol was prospectively registered in UMIN-CTR (UMIN 000048025). RESULTS: Of the 1553 studies identified, 36 studies were full-text reviewed, and 12 studies with 1132 patients were included in the meta-analysis. Pooled sensitivity and specificity were 0.82 [95% confidence interval (CI) 0.68-0.91] and 0.98 [95% CI 0.92-0.99] for obstructive shock, 0.78 [95% CI 0.56-0.91] and 0.96 [95% CI 0.92-0.98] for cardiogenic shock, 0.90 [95% CI 0.84-0.94] and 0.92 [95% CI 0.88-0.95] for hypovolemic shock, and 0.79 [95% CI 0.71-0.85] and 0.96 [95% CI 0.91-0.98] for distributive shock, respectively. The area under the receiver operating characteristic curve for each type of shock was approximately 0.95. The positive likelihood ratios for each type of shock were all greater than 10, especially 40 [95% CI 11-105] for obstructive shock. The negative likelihood ratio for each type of shock was approximately 0.2. CONCLUSIONS: The identification of the etiology for each type of shock using POCUS was characterized by high sensitivity and positive likelihood ratios, especially for obstructive shock.

Tumor DNA in Peritoneal Lavage as a Novel Biomarker for Predicting Peritoneal Recurrence in Patients With Gastric Cancer.

BACKGROUND: Peritoneal lavage cytology positivity (CY1) has been identified as a prognostic factor for distant metastases that is equivalent to peritoneal dissemination in Japan. Peritoneal lavage cytology is usually diagnosed by microscopic findings; a diagnostic procedure using a liquid biopsy (LB) technique has not yet been established. PATIENTS AND METHODS: We evaluated the feasibility of a LB approach using peritoneal lavage samples from 15 patients with gastric cancer. Samples were collected from both the Douglas pouch and the left subdiaphragmatic area, and cell-free DNA was extracted for analysis of TP53 mutations using droplet digital polymerase chain reaction. RESULTS: All 10 patients with CY1 had positive cytology for the left subdiaphragmatic specimen. However, only six out of the 10 patients had positive cytology for their Douglas pouch specimens, and these six patients had peritoneal tumor DNA (ptDNA) in these specimens. In all five patients with CY0, ptDNA was not detected. The overall survival was significantly shorter in the ptDNA-positive group than in the ptDNA-negative group. The survival of the group with a high amount of DNA from free intraperitoneal cells (ficDNA) was significantly worse than that of those with a low amount. In contrast, the group with a high amount of DNA from peritoneal cell-free DNA (pcfDNA) had significantly better survival than the group with a low amount. CONCLUSION: LB cytology showed equivalent utility to that of conventional microscopic examinations regarding its diagnostic ability. Therefore ptDNA, pcfDNA and ifcDNA are expected to be useful as prognostic factors.

Multiancestry genomic and transcriptomic analysis of gastric cancer.

Gastric cancer is among the most common malignancies worldwide, characterized by geographical, epidemiological and histological heterogeneity. Here, we report an extensive, multiancestral landscape of driver events in gastric cancer, involving 1,335 cases. Seventy-seven significantly mutated genes (SMGs) were identified, including ARHGAP5 and TRIM49C. We also identified subtype-specific drivers, including PIGR and SOX9, which were enriched in the diffuse subtype of the disease. SMGs also varied according to Epstein-Barr virus infection status and ancestry. Non-protein-truncating CDH1 mutations, which are characterized by in-frame splicing alterations, targeted localized extracellular domains and uniquely occurred in sporadic diffuse-type cases. In patients with gastric cancer with East Asian ancestry, our data suggested a link between alcohol consumption or metabolism and the development of RHOA mutations. Moreover, mutations with potential roles in immune evasion were identified. Overall, these data provide comprehensive insights into the molecular landscape of gastric cancer across various subtypes and ancestries.

The first case of robotic-assisted transabdominal retrorectus repair for incisional hernia in Japan.

Extraperitoneal mesh repair for ventral hernia has garnered attention and its rate has been increasing due to concerns for the potential complications of intraperitoneal mesh repair. Recently, robotic-assisted ventral hernia repair is highlighted as a solution to the technically demanding nature of laparoscopic transabdominal or enhanced-view totally extraperitoneal retrorectus ventral hernia repair. A 78-year-old man, who had undergone robot-assisted radical prostatectomy 10 months earlier, presented with an incisional hernia of European Hernia Society Classification M3W2, length 4 cm, width 5 cm with rectus diastasis. A right single-docking robotic-assisted transabdominal retrorectus repair was performed using a 21 by 14 cm self-gripping mesh and anterior wall reconstruction was done by 0 barbed nonabsorbable running suture. There were no complications and recurrence observed during a 7 months postoperative period. Single-docking robotic-assisted transabdominal retrorectus repair was considered a good option for midline moderate-size incisional hernias from the point of view of the ease of suturing, adequateness of dissection and prevention of bowel injury.

Reduction of White Spot Defects in CMOS Image Sensors Fabricated Using Epitaxial Silicon Wafer with Proximity Gettering Sinks by CH2P Molecular Ion Implantation.

Using a new implantation technique with multielement molecular ions consisting of carbon, hydrogen, and phosphorus, namely, CH2P molecular ions, we developed an epitaxial silicon wafer with proximity gettering sinks under the epitaxial silicon layer to improve the gettering capability for metallic impurities. A complementary metal-oxide-semiconductor (CMOS) image sensor fabricated with this novel epitaxial silicon wafer has a markedly reduced number of white spot defects, as determined by dark current spectroscopy (DCS). In addition, the amount of nickel impurities gettered in the CH2P-molecular-ion-implanted region of this CMOS image sensor is higher than that gettered in the C3H5-molecular-ion-implanted region; and this implanted region is formed by high-density black pointed defects and deactivated phosphorus after epitaxial growth. From the obtained results, the CH2P-molecular-ion-implanted region has two types of complexes acting as gettering sinks. One includes carbon-related complexes such as aggregated C-I, and the other includes phosphorus-related complexes such as P4-V. These complexes have a high binding energy to metallic impurities. Therefore, CH2P-molecular-ion-implanted epitaxial silicon wafers have a high gettering capability for metallic impurities and contribute to improving the device performance of CMOS image sensors. (This manuscript is an extension from a paper presented at the 6th IEEE Electron Devices Technology & Manufacturing Conference (EDTM 2022)).

Differential Impact of Renal Function on the Diagnostic Performance of Resting Full-Cycle Ratio in Patients With Renal Dysfunction.

Background: Physiological assessments using fractional flow reserve (FFR) and resting full-cycle ratio (RFR) have been recommended for revascularization decision making. Previous studies have shown a 20% rate of discordance between FFR and RFR. In this context, the correlation between RFR and FFR in patients with renal dysfunction remains unclear. This study examined correlations between RFR and FFR according to renal function. Methods and Results: In all, 263 consecutive patients with 370 intermediate lesions were enrolled in the study. Patients were classified into 3 groups according to renal function: Group 1, estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2; Group 2, 30 mL/min/1.73 m2≤eGFR<60 mL/min/1.73 m2; Group 3, eGFR <30 mL/min/1.73 m2. The discordance between FFR and RFR was assessed using known cut-off values for FFR (≤0.80) and RFR (≤0.89). Of the 370 lesions, functional significance with FFR was observed in 154 (41.6%). RFR was significantly correlated with FFR in all groups (Group 1, R2=0.62 [P<0.001]; Group 2, R2=0.67 [P<0.001]; Group 3, R2=0.46 [P<0.001]). The rate of discordance between RFR and FFR differed significantly among the 3 groups (Group 1, 18.8%; Group 2, 18.5%; Group 3, 42.9%; P=0.02). Conclusions: The diagnostic performance of RFR differed based on renal function. A better understanding of the clinical factors contributing to FFR/RFR discordance, such as renal function, may facilitate the use of these indices.

High-fluence and high-gain multilayer focusing optics to enhance spatial resolution in femtosecond X-ray laser imaging.

With the emergence of X-ray free-electron lasers (XFELs), coherent diffractive imaging (CDI) has acquired a capability for single-particle imaging (SPI) of non-crystalline objects under non-cryogenic conditions. However, the single-shot spatial resolution is limited to ~5 nanometres primarily because of insufficient fluence. Here, we present a CDI technique whereby high resolution is achieved with very-high-fluence X-ray focusing using multilayer mirrors with nanometre precision. The optics can focus 4-keV XFEL down to 60 nm × 110 nm and realize a fluence of >3 × 105 J cm-2 pulse-1 or >4 × 1012 photons µm-2 pulse-1 with a tenfold increase in the total gain compared to conventional optics due to the high demagnification. Further, the imaging of fixed-target metallic nanoparticles in solution attained an unprecedented 2-nm resolution in single-XFEL-pulse exposure. These findings can further expand the capabilities of SPI to explore the relationships between dynamic structures and functions of native biomolecular complexes.

Factors Contributing to Tumor Shrinkage after Peptide Receptor Radionuclide Therapy in Patients with Unresectable Neuroendocrine Tumors.

Peptide receptor activation therapy (PRRT) is a promising treatment option for metastatic neuroendocrine tumors (NETs). However, predicting tumor shrinkage before treatment is challenging. We analyzed the shrinkage rate of each metastatic tumor lesion to identify predictive factors related to shrinkage. Patients with metastatic NET who underwent PRRT were included in this retrospective study. For each patient, between one to five metastatic lesions were selected in descending order of size, and the change in the maximum tumor diameter after treatment was defined as the shrinkage rate per lesion (L-SR). We analyzed the relationship between pretreatment clinicopathological factors and L-SR. The median L-SR of all 75 lesions in 20 patients was 20% (95% CI: 4.8−26.1%). While previous treatment with cytotoxic agents (34.4%, p < 0.05) and primary tumor of the pancreas (27.8%, p < 0.05) were significantly favorable factors, a primary tumor of the rectum was significantly more resistant to shrinkage (−20.5%, p < 0.001). Therefore, lesion-based analysis of PRRT for NETs showed that pancreatic NET and previous treatment with cytotoxic agents were favorable factors for tumor shrinkage; however, rectal NET was a factor associated with resistance to shrinkage.

Effects of implant surface mechanical instrumentation methods on peri-implantitis: An in vitro study using a circumferential bone defect model.

Background/purpose: Although several mechanical and chemical debridement techniques have been reported for the management of peri-implantitis, there is no consensus on the most effective method at present. This in vitro study aimed to examine the effects of different mechanical instrumentation techniques on the debridement of hard calcified materials, which are present on the implant surface, as well as the effect of the defect morphology. Materials and methods: From a total of 15 implants, five each were assigned to one of three decontamination groups (Rotary titanium brush [Ti], tricalcium phosphate air powder abrasive treatment [Air], and titanium ultrasonic scaler [US] groups); the exposed hydroxyapatite (HA)-coated portion was divided into three 1-mm sections (coronal, middle, and apical). The residual-HA of each portion was measured using a digital microscope. Results: The overall percentage of residual HA coating was significantly lower in the US group than in the Ti or Air groups (p < 0.01). The percentage of residual HA in the coronal portion was significantly lower in the Ti and US groups than in the Air group (p < 0.05 and p < 0.01, respectively). The percentage of residual HA in the middle portion was significantly lower in the US group than in the Air group (p < 0.01). The percentage of residual HA in the apical portion was significantly lower in the Ti group than in the Air or US groups (p < 0.01). Conclusion: Ti and US were more effective for shallow defects, whereas US was more effective for deeper defects.

Case reports: chemoradiotherapy for locally advanced neuroendocrine carcinoma of the gallbladder.

Neuroendocrine carcinoma (NEC) is a rare subtype of malignant gallbladder tumor. Although surgical resection is the only potentially curative therapy for gallbladder NEC, most cases are surgically unresectable because of advanced stage disease and/or biologically aggressive behavior. The standard palliative treatment for malignant gallbladder tumors is chemotherapy; however, the efficacy of chemoradiotherapy in the treatment of gallbladder tumors is controversial. Here, we report a case of gallbladder NEC that showed a durable response to chemoradiotherapy. A 68-year-old Japanese man presented with a huge gallbladder tumor with liver and duodenal invasion. Pathological findings revealed poorly differentiated NEC of the gallbladder. After seven cycles of chemotherapy comprising cisplatin and irinotecan, computed tomography (CT) revealed remarkable tumor shrinkage, but an enlarged portal lymph node. The patient was treated with 50.4 Gy in 28 fractions with two cycles of cisplatin and etoposide. After chemoradiotherapy, the enlarged lymph node also decreased in size. Maximum standardized uptake value of fluorodeoxyglucose-positron emission tomography/CT(FDG-PET/CT) changed from 8.2 to physiological accumulation. We defined this condition as a complete response on both enhanced CT and FDG-PET/CT; therefore, we did not perform systemic treatment and only observed his condition. This patient remained healthy with no recurrence at 3 years after chemoradiotherapy.

Effectiveness of Naldemedine Compared with Magnesium Oxide in Preventing Opioid-Induced Constipation: A Randomized Controlled Trial.

Opioid-induced constipation (OIC) may occur in patients receiving opioid treatment, decreasing their quality of life (QOL). We compared the effectiveness of magnesium oxide (MgO) with that of naldemedine (NAL) in preventing OIC. This proof-of-concept, randomized controlled trial (registration number UMIN000031891) involved 120 patients with cancer scheduled to receive opioid therapy. The patients were randomly assigned and stratified by age and sex to receive MgO (500 mg, thrice daily) or NAL (0.2 mg, once daily) for 12 weeks. The change in the average Japanese version of Patient Assessment of Constipation QOL (JPAC-QOL) from baseline to 2 weeks was assessed as the primary endpoint. The other endpoints were spontaneous bowel movements (SBMs) and complete SBMs (CSBMs). Deterioration in the mean JPAC-QOL was significantly lower in the NAL group than in the MgO group after 2 weeks. There were fewer adverse events in the NAL group than in the MgO group. Neither significant differences in the change in SBMs between the groups nor serious adverse events/deaths were observed. The CSBM rate was higher in the NAL group than in the MgO group at 2 and 12 weeks. In conclusion, NAL significantly prevented deterioration in constipation-specific QOL and CSBM rate compared with MgO.

Evaluation of postgastrectomy symptoms and daily lives of small remnant distal gastrectomy for upper-third gastric cancer using a large-scale questionnaire survey.

Aim: Total gastrectomy (TG) is often performed for proximal gastric cancer. Small remnant distal gastrectomy (SRDG) can also be used in cases where surgical margins can be secured. The impact of preserving proximal small remnant stomach on postoperative quality of life (QOL) has not been fully elucidated. In the present study, we compared postgastrectomy symptoms and daily lives between patients undergoing SRDG and those undergoing TG for proximal gastric cancer using the developed Postgastrectomy Syndrome Assessment Scale (PGSAS)-45. Methods: Of the 1909 patients enrolled in the PGSAS NEXT study, univariate analysis of 19 main outcomes measures (MOMs) of PGSAS-45 was performed in patients undergoing TG (n = 1020) or SRDG (n = 54). Multiple regression analysis was performed with several clinical factors as explanatory variables. Results: There was no difference in age and sex between TG and SRDG groups. In SRDG group, postoperative period was shorter, the rates of laparoscopic approach and preservation of the celiac branch of the vagus nerve were higher, and the rates of clinical stage III/IV disease, ≥D2 dissection, and combined resection with other organs were lower than in the TG group significantly (P < .05). SRDG was associated with significantly lower symptoms and better daily lives than TG in 12 and 13 of 19 MOMs in PGSAS-45 by univariate and multiple regression analyses, respectively (P < .05). Several other clinical factors were also associated with certain MOMs. Conclusion: The PGSAS-45 revealed that SRDG was associated with better postgastrectomy symptoms and daily lives than TG.

Femtosecond X-ray Laser Reveals Intact Sea-Island Structures of Metastable Solid-State Electrolytes for Batteries.

Experimental characterization of the nanostructure of metastable functional materials has attracted significant attention with recent advances in computational materials discovery. However, since metastable glass-ceramics are easily damaged by irradiation, damage-free nanoimaging has not been realized thus far. Herein, we propose novel high-contrast coherent diffractive imaging that quantitatively analyzes the intact internal nanostructure of metastable glass-ceramics using femtosecond X-ray pulses. The immersion of sample particles in a solvent helps enhance the reconstructed image contrast and allows us to distinguish an ∼7% electron density difference between an amorphous form and crystals. Furthermore, morphological operations with a band-pass filter quantitatively elucidate the depth information. The evaluated volume ratio of the amorphous to crystalline phases is ∼2.5:1 for the measured metastable (Li2S)70-(P2S5)30 glass-ceramic particle. Sulfide glass-ceramics are used as electrolytes for all-solid-state batteries, which are indispensable for reducing the carbon footprint. Our results will facilitate structural studies on fragile metastable materials with important scientific and industrial implications.

Assessment of Ultra-Early-Stage Liver Fibrosis in Human Non-Alcoholic Fatty Liver Disease by Second-Harmonic Generation Microscopy.

Non-alcoholic fatty liver disease (NAFLD) is associated with the chronic progression of fibrosis. In general, the progression of liver fibrosis is determined by a histopathological assessment with a collagen-stained section; however, the ultra-early stage of liver fibrosis is challenging to identify because of the low sensitivity in the collagen-selective staining method. In the present study, we demonstrate the feasibility of second-harmonic generation (SHG) microscopy in the histopathological diagnosis of the liver of NAFLD patients for the quantitative assessment of the ultra-early stage of fibrosis. We investigated four representative NAFLD patients with early stages of fibrosis. SHG microscopy visualised well-matured fibrotic structures and early fibrosis diffusely involving liver tissues, whereas early fibrosis is challenging to be identified by conventional histopathological methods. Furthermore, the SHG emission directionality analysis revealed the maturation of each collagen fibre of each patient. As a result, SHG microscopy is feasible for assessing liver fibrosis on NAFLD patients, including the ultra-early stage of liver fibrosis that is difficult to diagnose by the conventional histopathological method. The assessment method of the ultra-early fibrosis by using SHG microscopy may serve as a crucial means for pathological, clinical, and prognostic diagnosis of NAFLD patients.

Ultraviolet Light-Emitting Diode (UV-LED) Sterilization of Citrus Bacterial Canker Disease Targeted for Effective Decontamination of Citrus Sudachi Fruit.

A kind of citrus fruit with special flavor, Citrus sudachi harvested in Japan, are exported to various countries. However, the Citrus sudachi needs to be sterilized using aqueous solution of sodium hypochlorite because there is a possibility of the adhesion of citrus bacterial canker (CBC) which is not found in Europe. Due to the sterilization with time-consuming work, a more effective decontamination technique is required. A decontamination method using ultraviolet (UV) light irradiation is thus anticipated. Especially, the use of light emitting diodes (LEDs) wi UV light has many advantages in terms of energy consumption, lifetime, and compactness； although an appropriate method is yet to be established. In this study, we evaluate the fundamental effectiveness of UV-LED decontamination on the basis of the bactericidal ability on CBC in petri dishes, using six kinds of UV-LEDs (265, 280, 285, 300, 310, and 365 nm) . For each irradiation, the resultant bactericidal abilities (BAs) were evaluated precisely taking into account the differences in their optical absorptions. In addition, BAs per unit photon number were also estimated, as a fundamental wavelength-dependence of BA. As a result, the effectiveness of UV-LED irradiation with relatively short wavelengths was demonstrated clearly.