Effects of one-hour daily outdoor access on milk yield and composition and behaviors of tethered dairy cows.

Objective: We investigated the effects of outdoor access for one-hour per day (ODA) on milk yield and composition and behaviors of tethered dairy cows. Methods: Eleven all-day tethered dairy cows were treated the ODA for two weeks. To evaluate the effect of ODA on milk yield, we first calculated the average daily milk yield of each cow for three days during two weeks before the ODA, three days before the ODA, three days at the end of the ODA, and three days during two weeks after the ODA. We then compared the milk yield change during the ODA with that for two weeks before and two weeks after the ODA. The effects of ODA on milk compositions and behaviors were evaluated by comparing the average values for each composition and behavior for the three days before the ODA and the last three days of the ODA. Results: The decrease of milk yield during the two weeks of ODA was significantly higher than that during the two weeks before ODA (p<0.01). The milk fat rate was significantly higher during ODA than before ODA (p<0.05). Lactose rate was significantly lower during ODA than before ODA (p<0.05). The concentrations of milk urea nitrogen, ketone bodies, and free fatty acids in the milk were significantly higher during ODA than before ODA (p<0.05). The mean total duration per day of lying during ODA was significantly lower than that before ODA (p<0.05). The walking steps per one-hour outdoor access were 158.4 ± 54.7. The social behavior during the one-hour outdoor access of the 11 cows was 53 times/h/herd. . Conclusion: Our results suggested that ODA promotes the express of normal behavior in dairy cows, but even one hour of ODA decreases milk production in cows, which may drop producers' profits without some financial supplementation.

Dwell Time Prolongation and Identification of Single Nucleotides Passing through a Solid-State Nanopore by Using Ammonium Sulfate Aqueous Solution.

The ionic current blockades when poly(dT)60 or dNTPs passed through SiN nanopores in an aqueous solution containing (NH4)2SO4 were investigated. The dwell time of poly(dT)60 in the nanopores in an aqueous solution containing (NH4)2SO4 was significantly longer compared to that in an aqueous solution that did not contain (NH4)2SO4. This dwell time prolongation effect due to the aqueous solution containing (NH4)2SO4 was also confirmed when dCTP passed through the nanopores. In addition, when the nanopores were fabricated via dielectric breakdown in the aqueous solution containing (NH4)2SO4, the dwell time prolongation effect for dCTP still occurred even after the aqueous solution was displaced with the aqueous solution without (NH4)2SO4. Furthermore, we measured the ionic current blockades when the four types of dNTPs passed through the same nanopore, and the four types of dNTPs could be statistically identified according to their current blockade values.

Effects of one hour daily outdoor access on lying and sleeping postures, and immune traits of tethered cows.

OBJECTIVE: We investigated the effects of outdoor access for 1 h per day on the animal welfare (AW) of tethered cows, in terms of lying and sleeping postures, and immune function. METHODS: A total of five dry cows were tethered all day indoors (tethering) for 30 days and then tethered indoors with 1 h daily outdoor access (ODA-1h) for 30 days. To analyze the effects of ODA-1h, we calculated the total duration and bout frequency per day, and bout duration of lying and sleeping postures during the last five days of each treatment period. We also analyzed the populations of T cells, B cells, and NK cells in peripheral blood mononuclear cells (PBMC) by fluorescence-activated cell sorting and determined the concanavalin A (Con A) -induced proliferation rate of T cells. RESULTS: The mean total time per day of lying during the ODA-1h treatment was significantly shorter than that during the tethering treatment (p<0.001). The Con A-induced proliferation rate of T cells during the ODA-1h treatment was significantly higher than that during the tethering treatment (p = 0.007). The proportion of NK cells in PBMC during the ODA-1h treatment tended to be higher than that during the tethering treatment (p = 0.062). CONCLUSION: Although ODA-1h may decrease lying time, it increases the available space for tethered cows towards that typically found in grazing and free barn feeding systems. This increased available space promotes the expression of normal behaviors such as walking and social behaviors except lying and may also improve the immune function of tethered dry cows, thereby improving their overall welfare.

Meat the challenge: Segmentation and profiling of Japanese beef mince and its substitutes consumers.

Shifts in protein production methods are an emerging challenge toward realizing a sustainable society. This paper aims to examine preferences among Japanese consumers regarding attributes of beef mince and its substitutes, to develop consumer segments based on these preferences, and to explore the segment with higher acceptance of replacement from conventional products. This paper also aims to explain intersegment differences from consumer heterogeneity in human values, scientific literacy, and sociodemographic viewpoints for a deeper understanding of consumer behavior in each segment. The results of an online choice experiment involving 4421 consumers in Japan, using food labels on mince showed that Japanese-origin organic beef was associated with the highest utility among the five production methods mentioned. Five consumer segments were identified with latent class analysis: novelty accepters, generous customers, attribute-economy balancers, price-conscious, and conservatives, which vary in preference in choice behavior, sociodemographic, human values, and scientific literacy.

Effect of different cow floor mat on the pressure in anterior knees of Holstein dry cows determined using pressure measurement sheet.

To analyze limb pain in tethered dairy cows, we compared three cow floor mat materials (pasture mat® [PM], KKM rubber mat® [RM], and woodchip [WC]) with soil ground considering the pressure applied to the anterior knee of Holstein cows. Three Holstein dry cows (791.3 ± 44.6 kg, 3.8 ± 1.1 years old) moored at the Education and Research Center of Alpine Field Science of the Faculty of Agriculture, Shinshu University, were tested. Pressure applied to the anterior knee of the cow by four different floor mat materials was compared using a commercially available pressure measurement sheet. The sustained pressures applied to the anterior knee of the test cow were 7.2 ± 1. 5, 29.3 ± 5.1, 17.0 ± 1.4, and 27.7 ± 2.5 MPa in the control, RM, PM, and WC, respectively, showing significant lower values (P < 0.05) than in the control. Sustained pressure was significantly lower in the PM than in the other treatments (P < 0.05). The RM was 41.7% cheaper than the PM. The pressure applied to the anterior knee of cow is lower on PM than on RM and WC. PM was more costly than RM but the sustained pressure was much lower on PM.

Effects of starvation-induced negative energy balance on endoplasmic reticulum stress in the liver of cows.

OBJECTIVE: Endoplasmic reticulum (ER) stress engages the unfolded protein response (UPR) that serves as an important mechanism for modulating hepatic fatty acid oxidation and lipogenesis. Chronic fasting in mice induced the UPR activation to regulate lipid metabolism. However, there is no direct evidence of whether negative energy balance (NEB) induces ER stress in the liver of cows. This study aimed to elucidate the relationship between the NEB attributed to feed deprivation and ER stress in bovine hepatocytes. METHODS: Blood samples and liver biopsy tissues were collected from 6 non-lactating cows before and after their starvation for 48 h. The blood non-esterified fatty acids (NEFA), ß-hydroxybutyric acid (BHBA) and glucose level were analyzed. Real-time quantitative polymerase chain reaction and Western blotting were used to explore the regulation of genes associated with UPR and lipid metabolism. RESULTS: The starvation increased the plasma BHBA and NEFA levels and decreased the glucose level. Additionally, the starvation caused significant increases in the mRNA expression level of spliced X-box binding protein 1 (XBP1s) and the protein level of phosphorylated inositol-requiring kinase 1 alpha (p-IRE1α; an upstream protein of XBP1) in the liver. The mRNA expression levels of peroxisome proliferator-activated receptor alpha and its target fatty acid oxidation- and ketogenesis-related genes were significantly upregulated by the starvation-mediated NEB. Furthermore, we found that the mRNA expression levels of lipogenic genes were not significantly changed after starvation. CONCLUSION: These findings suggest that in the initial stage of NEB in dairy cows, the liver coordinates an adaptive response by activating the IRE1 arm of the UPR to enhance ketogenesis, thereby avoiding a fatty liver status.

Sub-10-nm-thick SiN nanopore membranes fabricated using the SiO2sacrificial layer process.

In our previous studies, ultrathin SiN membranes down to 3 nm in thickness were fabricated using the poly-Si sacrificial layer process, and nanopores were formed in those membranes. The region of the SiN membrane fabricated using this process was small, and the poly-Si sacrificial layer remained throughout the other region. On the other hand, to reduce the noise of the current through the nanopore, it is preferable to reduce the capacitance of the nanopore chip by replacing the poly-Si layer with an insulator with low permittivity, such as SiO2. Thus, in this study, the fabrication of SiN membranes with thicknesses of 3-7 nm using the SiO2sacrificial layer process was examined. SiN membranes with thicknesses of less than 5 nm could not be formed when the thickness of the top SiN layer deposited onto the sacrificial layer was 100 nm. In contrast, SiN membranes down to 3.07 nm in thickness could be formed when the top SiN layer was 40 nm in thickness. This is thought to be due to the difference in membrane stress. Nanopores were then fabricated in the membranes via dielectric breakdown. The current noise of the nanopore membranes was approximately 3/5 that of membranes fabricated using the poly-Si sacrificial layer process. Last, ionic current blockades were measured when poly(dT)60passed through the nanopores, and the effective thickness of the nanopores was estimated based on those current-blockade values. The effective thickness was approximately 4.8 nm when the deposited thickness of the SiN membrane was 6.03 nm. On the other hand, the effective thickness and the deposited thickness were almost the same when the deposited thickness was 3.07 nm. This suggests it became difficult to form a shape in which the thickness of the nanopore edge was thinner than the deposited membrane thickness as the deposited thickness decreased.

Effects of adding a commercial capsaicin fertilizer on the feeding behavior of sika deer (Cervus nippon).

We investigated the inhibitory effect of capsaicin fertilizer on feeding in deer. We tested four captive adult female deer. In Experiment 1, in addition to the treatment (intact) containing only a solid feed (HC), we mixed the fertilizer not containing capsaicin (F) or the capsaicin fertilizer (CF) in the solid feed. In addition, the solid feed was put on a wire net that capsaicin fertilizer was placed 5 cm below (SCF). We investigated their feeding behavior response. In Experiment 2, we changed the amount of substance (fertilizer and capsaicin fertilizer) mixed in the HC. We mixed different amounts (0, 50, 100, and 200 g) of the treatments other than the intact with HC and presented them to the deer, and investigated their feeding behavior response. In Experiment 1, intake in the F and CF decreased (p < .05). In Experiment 2, HC intake was significantly lower in the 100 and 200 g CF (p < .05). However, HC intake relatively increased by the last day in the CF 200 g too. The capsaicin fertilizer decreased the feeding behavior of deer by directly touching the mucous membranes of the deer nose and lips. However, the effects were decreased over time.

Low-frequency noise induced by cation exchange fluctuation on the wall of silicon nitride nanopore.

Nanopore-based biosensors have attracted attention as highly sensitive microscopes for detecting single molecules in aqueous solutions. However, the ionic current noise through a nanopore degrades the measurement accuracy. In this study, the magnitude of the low-frequency noise in the ionic current through a silicon nitride nanopore was found to change depending on the metal ion species in the aqueous solution. The order of the low-frequency noise magnitudes of the alkali metal ionic current was consistent with the order of the adsorption affinities of the metal ions for the silanol surface of the nanopore (Li

How Far Will Clinical Application of AI Applications Advance for Colorectal Cancer Diagnosis?

Integrating artificial intelligence (AI) applications into colonoscopy practice is being accelerated as deep learning technologies emerge. In this field, most of the preceding research has focused on polyp detection and characterization, which can mitigate inherent human errors accompanying colonoscopy procedures. On the other hand, more challenging research areas are currently capturing attention: the automated prediction of invasive cancers. Colorectal cancers (CRCs) harbor potential lymph node metastasis when they invade deeply into submucosal layers, which should be resected surgically rather than endoscopically. However, pretreatment discrimination of deeply invasive submucosal CRCs is considered difficult, according to previous prospective studies (e.g., <70% sensitivity), leading to an increased number of unnecessary surgeries for large adenomas or slightly invasive submucosal CRCs. AI is now expected to overcome this challenging hurdle because it is considered to provide better performance in predicting invasive cancer than non-expert endoscopists. In this review, we introduce five relevant publications in this area. Unfortunately, progress in this research area is in a very preliminary phase, compared to that of automated polyp detection and characterization, because of the lack of number of invasive CRCs used for machine learning. However, this issue will be overcome with more target images and cases. The research field of AI for invasive CRCs is just starting but could be a game changer of patient care in the near future, given rapidly growing technologies, and research will gradually increase.

Fermentative Quality and Animal Acceptability of Ensiled Persimmon Skin with Absorbents for Practical Use in Ruminant Feed.

Persimmon skin (PS), while representing an attractive feed source, requires an appropriate preservation procedure to increase its shelf life. We assessed the fermentation quality, in vitro ruminal incubation, and intake of persimmon skin silage ensiled with different dry absorbents. We prepared the silage on a table scale (Experiment 1) and evaluated five different mixtures: PS without an additive, PS plus Lactobacillus buchneri inoculum (LB), and PS plus LB plus each of the absorbents kraft pulp, wheat bran, or beet pulp. We opened the laboratory bags, kept at 25 °C, at 0, 14, 28, and 60 days for fermentation quality and chemical analysis (n = 3 for each measurement). Further, with an in vitro rumen simulated cultivation study (Experiment 2), we evaluated the fermentation pattern of PS with a mixture of two absorbents (kraft pulp and wheat bran) either raw (no fermentation) or ensiled (n = 4 for each treatment). Finally, we conducted an in vivo experiment using six dry ewes assigned based on their body weight to two experimental groups in a crossover design of two periods (Experiment 3). We fed a control group a 100% basal diet (tall fescue hay and concentrate mixture) and ensiled PS (PSS) group, a 20% dry matter substitution of tall fescue with PS silage mixed with kraft pulp as the sole absorbent. The results of Experiment 1 show, regardless of the absorbents used, the effluent volume of the lab bags was lower in absorbent-treated groups (p < 0.001). In Experiment 2, the condition of the PS with absorbents (raw or ensiled) did not affect the total gas production (p > 0.05), but we observed an increased propionate proportion in PSS with absorbents compared to basal diet (p = 0.019). The proportion of methane to the total gas in PSS group was considerably reduced compared with that in the other groups (p < 0.001). As we did this incubation study with a single run, a more detailed evaluation in the future would verify these observations. In the animal trial (Experiment 3), dry matter intake was similar between groups (p > 0.05), but ewes spent a shorter time eating in the PSS-fed group (p = 0.011). Here we present the practical use of PSS as part of ruminant feed in which dry absorbents prevented dry matter loss.

Endocytoscopy with NBI has the potential to correctly diagnose diminutive colorectal polyps that are difficult to diagnose using conventional NBI.

Background and study aims Real-time diagnosis of colorectal polyps is needed to prevent unnecessary resection of benign polyps. The vessels in hyperplastic polyps sometimes mimic the characteristic meshed capillary network of neoplastic lesions on non-magnified narrow-band imaging (NBI). Endocytoscopy in conjunction with NBI (EC-NBI) enables more detailed vessel observation. The current study evaluated whether EC-NBI can accurately diagnose small colorectal lesions with visible vessels on non-magnified NBI. Patients and methods This retrospective study was conducted from January to December 2016. During colonoscopy, lesion images were obtained using NBI and EC-NBI. On EC-NBI, lesions were classified as having "clear," "unclear," or "invisible" blood vessel margins. All specimens were resected and pathologically examined, and the association between vessel margin findings and pathological diagnosis was assessed. The lesion surface to vessel depth was measured in clear, unclear, and invisible lesions. Results Among 114 adenomas, 108 were clear, while six were unclear. Among 36 hyperplastic polyps, eight were clear, while 28 were unclear. A micro-network (MN) pattern was seen in 106 of 114 adenomas, and four of 36 hyperplastic polyps. The sensitivity, specificity, correct diagnostic rate, and positive and negative predictive values of clear blood vessel margins or a MN pattern as an adenoma index were 98.2 %, 69.4 %, 91.3 %, 91.1 %, and 92.6 %, respectively. EC-NBI correctly diagnosed 69.4 % (25/36) of hyperplastic polyps. The lesion surface-blood vessel distance was greater in unclear versus clear lesions ( P  < 0.001), and invisible versus unclear lesions ( P  < 0.001). Conclusions EC-NBI may effectively differentiate hyperplastic polyps with visible vessels from adenomas. Blood vessel depth affects visibility.

Two Cases of Nonsuicidal Self-Injury Comprising Partial Autoamputation of the Apex of the Tongue.

The prevalence of nonsuicidal self-injury (NSSI) in adults is lower than that in adolescents and it is more prevalent in patients with psychiatric disorders. Sleep disturbances such as nightmares are associated with NSSI after accounting for depression; thus, persons with major NSSI sometimes present at medical institutions during the night seeking emergency treatment. Gingival tissues comprise the most frequent target of self-injury of the oral cavity using oral hygiene tools. Most NSSI in the oral cavity is minor because such tools are blunt. Major NSSI such as autoamputation of the tongue is rare. We describe two patients who partially autoamputated the apex of their own tongues using edged tools. Case 1 was a 55-year-old female with depression who had defaulted from psychiatric intervention. She had cut off her tongue using a Japanese kitchen knife and presented with the dry, necrotic amputated portion and blood oozing from the remainder of her tongue. We debrided and sutured the remainder of the tongue without reattaching the amputated portion. Her postoperative course was uneventful, and she was free of adverse events such as functional disability and wound infection. Case 2 was a 69-year-old female with schizophrenia who had defaulted from psychiatric intervention and had cut off her tongue using scissors. The amputated portion of the tongue was lost and the remainder, which was oozing blood, was debrided and sutured. She defaulted on a follow-up appointment. Neither of these patients had suicidal intent. The prevalence of NSSI across all age groups has recently increased, and the risk that self-injury will become normalized has become a concern. Thus, dentists as well as oral and maxillofacial surgeons should be aware of the possibility that patients will present with major NSSI requiring emergency treatment.

Solid-state nanopores towards single-molecule DNA sequencing.

Nanopore DNA sequencing offers a new paradigm owing to its extensive potential for long-read, high-throughput detection of nucleotide modification and direct RNA sequencing. Given the remarkable advances in protein nanopore sequencing technology, there is still a strong enthusiasm in exploring alternative nanopore-sequencing techniques, particularly those based on a solid-state nanopore using a semiconductor material. Since solid-state nanopores provide superior material robustness and large-scale integrability with on-chip electronics, they have the potential to surpass the limitations of their biological counterparts. However, there are key technical challenges to be addressed: the creation of an ultrasmall nanopore, fabrication of an ultrathin membrane, control of the ultrafast DNA speed and detection of four nucleotides. Extensive research efforts have been devoted to resolving these issues over the past two decades. In this review, we briefly introduce recent updates regarding solid-state nanopore technologies towards DNA sequencing. It can be envisioned that emerging technologies will offer a brand new future in DNA-sequencing technology.

Artificial Intelligence-assisted System Improves Endoscopic Identification of Colorectal Neoplasms.

BACKGROUND & AIMS: Precise optical diagnosis of colorectal polyps could improve the cost-effectiveness of colonoscopy and reduce polypectomy-related complications. However, it is difficult for community-based non-experts to obtain sufficient diagnostic performance. Artificial intelligence-based systems have been developed to analyze endoscopic images; they identify neoplasms with high accuracy and low interobserver variation. We performed a multi-center study to determine the diagnostic accuracy of EndoBRAIN, an artificial intelligence-based system that analyzes cell nuclei, crypt structure, and microvessels in endoscopic images, in identification of colon neoplasms. METHODS: The EndoBRAIN system was initially trained using 69,142 endocytoscopic images, taken at 520-fold magnification, from patients with colorectal polyps who underwent endoscopy at 5 academic centers in Japan from October 2017 through March 2018. We performed a retrospective comparative analysis of the diagnostic performance of EndoBRAIN vs that of 30 endoscopists (20 trainees and 10 experts); the endoscopists assessed images from 100 cases produced via white-light microscopy, endocytoscopy with methylene blue staining, and endocytoscopy with narrow-band imaging. EndoBRAIN was used to assess endocytoscopic, but not white-light, images. The primary outcome was the accuracy of EndoBrain in distinguishing neoplasms from non-neoplasms, compared with that of endoscopists, using findings from pathology analysis as the reference standard. RESULTS: In analysis of stained endocytoscopic images, EndoBRAIN identified colon lesions with 96.9% sensitivity (95% CI, 95.8%-97.8%), 100% specificity (95% CI, 99.6%-100%), 98% accuracy (95% CI, 97.3%-98.6%), a 100% positive-predictive value (95% CI, 99.8%-100%), and a 94.6% negative-predictive (95% CI, 92.7%-96.1%); these values were all significantly greater than those of the endoscopy trainees and experts. In analysis of narrow-band images, EndoBRAIN distinguished neoplastic from non-neoplastic lesions with 96.9% sensitivity (95% CI, 95.8-97.8), 94.3% specificity (95% CI, 92.3-95.9), 96.0% accuracy (95% CI, 95.1-96.8), a 96.9% positive-predictive value, (95% CI, 95.8-97.8), and a 94.3% negative-predictive value (95% CI, 92.3-95.9); these values were all significantly higher than those of the endoscopy trainees, sensitivity and negative-predictive value were significantly higher but the other values are comparable to those of the experts. CONCLUSIONS: EndoBRAIN accurately differentiated neoplastic from non-neoplastic lesions in stained endocytoscopic images and endocytoscopic narrow-band images, when pathology findings were used as the standard. This technology has been authorized for clinical use by the Japanese regulatory agency and should be used in endoscopic evaluation of small polyps more widespread clinical settings. UMIN clinical trial no: UMIN000028843.

Endocytoscopy for the differential diagnosis of colorectal low-grade adenoma: a novel possibility for the "resect and discard" strategy.

BACKGROUND AND AIMS: Endocytoscopy, a next-generation endoscopic system, facilitates observation at a maximum magnification of ×520. To our knowledge, no study has reported high-precision diagnosis of colorectal low-grade adenoma, endoscopically. We aimed to reveal which endocytoscopic findings may be used as indicators of low-grade adenoma and to assess whether a "resect and discard" strategy using endocytoscopy is feasible. METHODS: Lesions diagnosable with endocytoscopy were examined retrospectively between May 2005 and July 2017. A normal pit-like structure in endocytoscopic images was considered a normal pit (NP) sign and used as an indicator of low-grade adenoma. The primary outcome was the diagnostic accuracy of the NP sign for low-grade adenoma. We evaluated agreement rates between endocytoscopic and pathologic diagnosis for surveillance colonoscopy interval recommendation (SCIR) and performed a validation study to verify the agreement rates. RESULTS: For 748 lesions in 573 cases diagnosed as colorectal adenoma using endocytoscopy, the results were as follows: sensitivity of the NP sign for low-grade adenoma, 85.0%; specificity, 90.7%; positive predictive value, 96.6%; negative predictive value, 66.1%; accuracy, 86.4%; and positive likelihood ratio, 9.2 (P < .001). The agreement rate between endocytoscopic and pathologic diagnosis for SCIR was 94.4% (95% confidence interval [CI], 92.2%-96.1%; P < .001) under United States guidelines and 96.3% (95% CI, 94.5%-97.7%; P < .001) under European Union guidelines. All inter- and intraobserver agreement rates for expert and nonexpert endoscopists had κ values ≥0.8 except one nonexpert pair. CONCLUSIONS: Endocytoscopy is an effective modality in determining the differential diagnosis of colorectal low-grade adenoma. (University Hospital Medical Information Network Clinical Trials database registration number: UMIN000018623.).

Nivolumab-induced cholangitis in patients with non-small cell lung cancer: Case series and a review of literature.

Immune checkpoint inhibitors (ICIs), including nivolumab, have exhibited substantial benefits in the treatment of several types of cancers. However, treatment with ICIs is often accompanied by immune-related adverse events (irAEs), and a clear understanding of the precise indications and management of irAEs is important for harnessing the full potential of these agents. While skin- or gastrointestinal-associated irAEs have been relatively well studied, there are few reports regarding nivolumab-induced cholangitis. We retrospectively reviewed data from patients with advanced or recurrent non-small cell lung cancer who were treated with nivolumab between December 2015 and December 2018 at Tottori University in Japan. Among the 59 patients, we identified four patients who experienced nivolumab-induced cholangitis. Of these four patients, stable disease (SD) was observed in two patients (50%), while partial response (PR) was achieved in two patients (50%) under nivolumab treatment. Patients were treated with corticosteroid alone (n=2) or in combination with mycophenolate mofetil (MMF) (n=2); these treatments resulted in improvements in nivolumab-induced cholangitis in three patients. In conclusion, the present retrospective study identified four cases of nivolumab-induced cholangitis. The combination of corticosteroid and MMF was effective in two cases with grade 4 nivolumab-induced cholangitis. Further reports are needed to establish the optimal management of patients with this irAE.

Stable fabrication of a large nanopore by controlled dielectric breakdown in a high-pH solution for the detection of various-sized molecules.

For nanopore sensing of various-sized molecules with high sensitivity, the size of the nanopore should be adjusted according to the size of each target molecule. For solid-state nanopores, a simple and inexpensive nanopore fabrication method utilizing dielectric breakdown of a membrane is widely used. This method is suitable for fabricating a small nanopore. However, it suffers two serious problems when attempting to fabricate a large nanopore: the generation of multiple nanopores and the non-opening failure of a nanopore. In this study, we found that nanopore fabrication by dielectric breakdown of a SiN membrane under high-pH conditions (pH ≥ 11.3) could overcome these two problems and enabled the formation of a single large nanopore up to 40 nm in diameter within one minute. Moreover, the ionic-current blockades derived from streptavidin-labelled and non-labelled DNA passing through the fabricated nanopore were clearly distinguished. The current blockades caused by streptavidin-labelled DNA could be identified even when its concentration is 1% of the total DNA.

Silicon nitride nanopore created by dielectric breakdown with a divalent cation: deceleration of translocation speed and identification of single nucleotides.

Nanopore DNA sequencing with a solid-state nanopore requires deceleration of the ultrafast translocation speed of single-stranded DNA (ssDNA). We report an unexpected phenomenon: controlled dielectric breakdown (CBD) with a divalent metal cation, especially Ca2+, provides a silicon nitride nanopore with the ability to decelerate ssDNA speed to 100 µs per base even after solution replacement. This speed is two orders of magnitude slower than that for CBD with a conventional monovalent metal cation. Temperature dependence experiments revealed that the enthalpic barrier for a nanopore created via CBD with Ca2+ is 25-30kBT, comparable to that of a biological nanopore. The slowing effect originates from the strong interaction between ssDNA and divalent cations, which were coated on the sidewall of the nanopore during the CBD process. In addition, we found that the nanopore created via CBD with Ca2+ can decelerate the speed of even single-nucleotide monomers, dNMPs, to 0.1-10 ms per base. The four single nucleotides could be statistically identified according to their blockade currents. Our approach is simple and practical because it simultaneously allows nanopore fabrication, ssDNA deceleration and the identification of nucleotide monomers.

Artificial intelligence and colonoscopy: Current status and future perspectives.

BACKGROUND AND AIM: Application of artificial intelligence in medicine is now attracting substantial attention. In the field of gastrointestinal endoscopy, computer-aided diagnosis (CAD) for colonoscopy is the most investigated area, although it is still in the preclinical phase. Because colonoscopy is carried out by humans, it is inherently an imperfect procedure. CAD assistance is expected to improve its quality regarding automated polyp detection and characterization (i.e. predicting the polyp's pathology). It could help prevent endoscopists from missing polyps as well as provide a precise optical diagnosis for those detected. Ultimately, these functions that CAD provides could produce a higher adenoma detection rate and reduce the cost of polypectomy for hyperplastic polyps. METHODS AND RESULTS: Currently, research on automated polyp detection has been limited to experimental assessments using an algorithm based on ex vivo videos or static images. Performance for clinical use was reported to have >90% sensitivity with acceptable specificity. In contrast, research on automated polyp characterization seems to surpass that for polyp detection. Prospective studies of in vivo use of artificial intelligence technologies have been reported by several groups, some of which showed a >90% negative predictive value for differentiating diminutive (≤5 mm) rectosigmoid adenomas, which exceeded the threshold for optical biopsy. CONCLUSION: We introduce the potential of using CAD for colonoscopy and describe the most recent conditions for regulatory approval for artificial intelligence-assisted medical devices.