Intraoperative Assessment of Surgical Stress Response Using Nociception Monitor under General Anesthesia and Postoperative Complications: A Narrative Review.

We present a narrative review focusing on the new role of nociception monitor in intraoperative anesthetic management. Higher invasiveness of surgery elicits a higher degree of surgical stress responses including neuroendocrine-metabolic and inflammatory-immune responses, which are associated with the occurrence of major postoperative complications. Conversely, anesthetic management mitigates these responses. Furthermore, improper attenuation of nociceptive input and related autonomic effects may induce increased stress response that may adversely influence outcome even in minimally invasive surgeries. The original role of nociception monitor, which is to assess a balance between nociception caused by surgical trauma and anti-nociception due to anesthesia, may allow an assessment of surgical stress response. The goal of this review is to inform healthcare professionals providing anesthetic management that nociception monitors may provide intraoperative data associated with surgical stress responses, and to inspire new research into the effects of nociception monitor-guided anesthesia on postoperative complications.

Photon confinement in a silicon cavity of an image sensor by plasmonic diffraction for near-infrared absorption enhancement.

Silicon-based image sensors are attractive for applications in the near-infrared (NIR) range owing to their low-cost and high availability. However, novel approaches are required to enhance their light absorption, hindered by the silicon band gap. In this study, we proposed a light trapping strategy in a silicon absorption layer by plasmonic diffraction and reflection within a pixel to improve the sensitivity at a specific NIR wavelength for complementary metal-oxide semiconductor image sensors. The plasmonic grating diffracted light under the quasi-resonant condition of the surface plasmon polaritons. We simulated the silicon absorption efficiency for plasmonic diffraction combined with metal-filled trenches and a pre-metal dielectric (PMD) layer. Backward propagation light in silicon by a total internal reflection at the bottom decoupled with plasmonic grating. A single SiO2 protrusion was added at the silicon bottom to prevent decoupling by scattering the light in the silicon and trapping it within the pixel. In addition, the light transmitted to the PMD layer is reflected by the wiring layer used as a mirror. The photon confinement in silicon by these constructions improved the absorption by approximately 8.2 times at an NIR wavelength of 940 nm with 3-µm-thick. It is useful for NIR imaging system with active laser illumination.

Dielectric property measurement of human sweat using attenuated total reflection terahertz time domain spectroscopy.

Sweat is one of the essential biofluids produced by the human body, and it contains various physiological biomarkers. These biomarkers can indicate human health conditions such as disease and illness. In particular, imbalances in the concentration of electrolytes can indicate the onset of disease. These same imbalances affect the dielectric properties of sweat. In this study, we used attenuated total reflection terahertz time domain spectroscopy to obtain the frequency-dependent dielectric properties of human sweat in a frequency range from 200 GHz to 2.5 THz. We have investigated the variation of dielectric properties of sweat collected from different regions of the human body, and we have observed that the real and imaginary part of dielectric permittivity decreases with the increase in frequency. A combination of left-hand Jonscher and Havriliak-Negami processes is used to model the results and reveal the presence of relaxation processes related to sodium and calcium ions concentrations. This information may help design novel biosensors to understand the human health condition and provide a hydration assessment.

Near-infrared sensitivity improvement by plasmonic diffraction for a silicon image sensor with deep trench isolation filled with highly reflective metal.

We propose a plasmonic diffraction structure combined with deep trench isolation (DTI) filled with highly reflective metal to enhance the near-infrared (NIR) sensitivity of image sensors. The plasmonic diffraction structure has a silver grating on the light-illuminated surface of a typical silicon backside-illuminated CMOS image sensor. The structural parameters of the silver grating were investigated through simulations, and the mechanism of the NIR sensitivity enhancement was clarified. Under the quasi-resonant conditions of surface plasmon polaritons, incident NIR light effectively diffracted as a propagating light to the sensor silicon layer. The diffracted light travelled back and forth between the DTIs. The effective propagation length in silicon was extended to six times by silver-filled DTI, resulting in approximately five times improvement of the 3-µm-thick silicon absorption at a wavelength of 940 nm.

Development of a terahertz wave circular polarizer using a 2D array of metallic helix metamaterial.

We developed a broadband terahertz wave circular polarizer that consists of a two-dimensional (2D) array of three-dimensional metallic helices. Each helix operates in an axial mode of operation where the wavelength of resonance is comparable to the dimensions of the helix. We evaluated the performance of the polarizer using standard terahertz time domain spectroscopy, and we confirmed that the array of helices transmits a circularly polarized terahertz wave with opposite handedness as that of the helices. The polarizer covers the frequency range from 117 GHz to 208 GHz, close to one octave. We obtained the ellipticity of the circularly polarized terahertz wave close to unity in this frequency band.

COVID-19 information retrieval with deep-learning based semantic search, question answering, and abstractive summarization.

The COVID-19 global pandemic has resulted in international efforts to understand, track, and mitigate the disease, yielding a significant corpus of COVID-19 and SARS-CoV-2-related publications across scientific disciplines. Throughout 2020, over 400,000 coronavirus-related publications have been collected through the COVID-19 Open Research Dataset. Here, we present CO-Search, a semantic, multi-stage, search engine designed to handle complex queries over the COVID-19 literature, potentially aiding overburdened health workers in finding scientific answers and avoiding misinformation during a time of crisis. CO-Search is built from two sequential parts: a hybrid semantic-keyword retriever, which takes an input query and returns a sorted list of the 1000 most relevant documents, and a re-ranker, which further orders them by relevance. The retriever is composed of a deep learning model (Siamese-BERT) that encodes query-level meaning, along with two keyword-based models (BM25, TF-IDF) that emphasize the most important words of a query. The re-ranker assigns a relevance score to each document, computed from the outputs of (1) a question-answering module which gauges how much each document answers the query, and (2) an abstractive summarization module which determines how well a query matches a generated summary of the document. To account for the relatively limited dataset, we develop a text augmentation technique which splits the documents into pairs of paragraphs and the citations contained in them, creating millions of (citation title, paragraph) tuples for training the retriever. We evaluate our system ( http://einstein.ai/covid ) on the data of the TREC-COVID information retrieval challenge, obtaining strong performance across multiple key information retrieval metrics.

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4 +/15NH4 + Analyses via Sequential Conversion to N2O.

The importance of understanding the fate of nitrate (NO3-), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has been increasing because global nitrogen loads have dramatically increased following industrialization. Dissimilatory nitrate reduction to ammonium (DNRA) and denitrification are both microbial processes that use NO3- for respiration. Compared to denitrification, quantitative determinations of the DNRA activity have been carried out only to a limited extent. This has led to an insufficient understanding of the importance of DNRA in NO3- transformations and the regulating factors of this process. The objective of this paper is to provide a detailed procedure for the measurement of the potential DNRA rate in environmental samples. In brief, the potential DNRA rate can be calculated from the 15N-labeled ammonium (15NH4+) accumulation rate in 15NO3- added incubation. The determination of the 14NH4+ and 15NH4+ concentrations described in this paper is comprised of the following steps. First, the NH4+ in the sample is extracted and trapped on an acidified glass filter as ammonium salt. Second, the trapped ammonium is eluted and oxidized to NO3- via persulfate oxidation. Third, the NO3- is converted to N2O via an N2O reductase deficient denitrifier. Finally, the converted N2O is analyzed using a previously developed quadrupole gas chromatography-mass spectrometry system. We applied this method to salt marsh sediments and calculated their potential DNRA rates, demonstrating that the proposed procedures allow a simple and more rapid determination compared to previously described methods.

Neuropathic Characteristics In Patients With Persistent Idiopathic Facial Pain.

BACKGROUND: Persistent idiopathic facial pain (PIFP) is a subtype of painful cranial neuropathies and other facial pains. The involvement of neuropathic mechanisms in PIFP, however, remains controversial. Using the Douleur Neuropathique 4 (DN4) questionnaire, the present study examined neuropathic characteristics in patients with PIFP. METHODS: The multi-institutional retrospective study collected the following clinical data from 205 consecutive patients with adult chronic pain: gender, age, BMI, diseases causing chronic pain, disease duration, visual analogue scale score of pain strength, and DN4 score. To compare neuropathic characteristics between PIFP and postherpetic neuralgia (PHN), we selected patients with PIFP (n=19) and patients with PHN (n=33), and performing a case-control study in which each patient with PHN or PIFP was matched by age and gender (n=16 in each group). RESULTS: DN4 score was significantly lower in the PIFP group than in the PHN group before and after matching. The incidence when DN4 was ≥4 was 10.5% before matching and 12.5% after matching in the PIFP group, both of which were significantly lower than those in the PHN group before and after matching (66.7% and 75.0%). CONCLUSION: Ten percent of the PIFP patients likely show neuropathic pain characteristics.

Evaluating the Effect of Intravenous Acetaminophen in Multimodal Analgesia After Total Hip Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Postoperative pain is a significant concern of patients before surgery. Multimodal pain management is an effective method of pain control after major orthopedic surgery. Acetaminophen is the most commonly used analgesic for the management of pain. It was hypothesized that 1000 mg of intravenous acetaminophen (IA) dosed every 6 hours would significantly reduce the postoperative pain score at rest and the opioid consumption volume in patients who would undergo total hip arthroplasty (THA) when compared to a control group. METHODS: A single-center, prospective, open-label randomized control study was conducted. A total of 97 patients undergoing unilateral primary THA were divided into 2 groups: the study group (IA) (n = 45) and the control group (n = 52). The study group received administered IA after surgery, while the control group received only a standard pain control. Both groups received a preoperative femoral nerve block and postoperative intravenous fentanyl citrate. The primary outcome was the evaluation of the pain score at rest 24 hours after surgery. The pain score was measured using the Numerical Rating Scale. The primary outcome of this study was analyzed using generalized estimating equation. RESULTS: The IA group had a significant improvement in Numerical Rating Scale score at rest 24 hours after THA compared to the control group (-0.91, 95% confidence interval -1.56 to -0.26, P = .006), suggesting a positive effect of IA usage for pain relief. The total fentanyl citrate consumption after surgery for 24 hours was significantly lower in the IA group than those of the control group (52.07 ± 7.64 vs 57.83 ± 12.44 mg, P < .001). CONCLUSION: Postoperative administration of IA significantly reduced the postoperative pain score and opioid consumption volume after primary THA. IA was useful as one role of multimodal pain management after THA. LEVEL OF EVIDENCE: Level 2.

C-reactive Protein Level on Postoperative Day One is Associated with Chronic Postsurgical Pain After Mastectomy.

BACKGROUND: C-reactive protein (CRP) is an acute phase reactant released in response to inflammation or tissue injury. Inflammation is one of the pathogenic factors related to transition from acute postsurgical pain (APSP) to chronic postsurgical pain (CPSP). Although several risk factors are reportedly associated with CPSP, the effects of CRP levels on CPSP have not been examined. OBJECTIVES: The present study investigated the relationship between perioperative risk factors, including CRP levels on postoperative day one and CPSP, in patients undergoing mastectomy. METHODS: Preoperative anxiety and depression levels were evaluated in female patients undergoing mastectomy under general anesthesia, with or without peripheral nerve block. Patients with chronic preoperative pain and/or preoperative breast pain were excluded. The intensity of postoperative pain was prospectively examined one and six days, and three and twelve months after surgery using a numerical rating scale (NRS). RESULTS: The current researchers conducted univariate and multivariate linear regression analyses to explore risk factors for CPSP in 36 patients. Patient demographics, preoperative psychological states, and anesthetic managements showed no relationship with CPSP. On the other hand, pain intensity of APSP and CRP levels on postoperative day one was significantly associated with the pain intensity of CPSP. CONCLUSIONS: Postoperative CRP level is likely to be associated with the development of CPSP after mastectomy.

Topic detection using paragraph vectors to support active learning in systematic reviews.

Systematic reviews require expert reviewers to manually screen thousands of citations in order to identify all relevant articles to the review. Active learning text classification is a supervised machine learning approach that has been shown to significantly reduce the manual annotation workload by semi-automating the citation screening process of systematic reviews. In this paper, we present a new topic detection method that induces an informative representation of studies, to improve the performance of the underlying active learner. Our proposed topic detection method uses a neural network-based vector space model to capture semantic similarities between documents. We firstly represent documents within the vector space, and cluster the documents into a predefined number of clusters. The centroids of the clusters are treated as latent topics. We then represent each document as a mixture of latent topics. For evaluation purposes, we employ the active learning strategy using both our novel topic detection method and a baseline topic model (i.e., Latent Dirichlet Allocation). Results obtained demonstrate that our method is able to achieve a high sensitivity of eligible studies and a significantly reduced manual annotation cost when compared to the baseline method. This observation is consistent across two clinical and three public health reviews. The tool introduced in this work is available from https://nactem.ac.uk/pvtopic/.

Preoperative anxiety induces no clinically relevant effect on intraoperative nociceptive levels during breast surgery under general anesthesia.

Anxiety can affect acute and chronic postoperative pain after breast surgery. Nociceptive response during surgery might also be affected by preoperative anxiety even under unconscious state during general anesthesia. The aim of this retrospective study was to investigate nociceptive responses during breast surgery under general anesthesia in patients with or without preoperative anxiety. Patients (n = 45) were divided into a low-anxiety group (n = 25) and a high-anxiety group (n = 20) in accordance with preoperative scores for the State Trait Anxiety Inventory. We performed discriminant analysis to compare nociception during surgery using three intraoperative averaged values: heart rate; systolic blood pressure; and perfusion index. No significant differences in discriminant score were seen between groups (p = 0.10). Although we performed propensity score-matching to reduce the bias due to confounding variables in this retrospective study, there was also no significant difference in levels of nociceptive response between groups (p = 0.06). In conclusion, the level of nociception during breast surgery is not significantly affected by preoperative anxiety.

Comparison of the level of intraoperative nociception between laparoscopic and open hepatic resection.

BACKGROUND/AIMS: Sufficient suppression of perioperative nociception is important for ensuring favorable postoperative outcomes. Although the level of nociception during laparoscopic surgery is generally lower than during laparotomy, there is insufficient evidence to support this for hepatic resection. METHODOLOGY: To develop a method to retrospectively evaluate the intraoperative nociceptive level, we collected data of intraoperative averaged values of heart rate, perfusion index, systolic blood pressure during three surgeries with different levels of intraoperative nociception. After we validated the utility of discriminant analysis using these variables for the retrospective evaluation of nociception during surgery, we performed this analysis in patients who underwent either laparoscopic or open hepatic resection. RESULTS: Although there was a significant difference in discriminant score between the open and the laparoscopic hepatic resection groups before propensity score matching, discriminant score showed no significant difference between two groups after matching. CONCLUSIONS: The level of nociception during laparoscopic hepatic resection is likely similar to that during open hepatic resection. An assertive anti-nociceptive strategy might be required for laparoscopic procedures under general anesthesia, as with open procedures.