Effect of light intensity on behaviour, health and growth of growing-finishing pigs.

The effect of light intensity has been explored in relation to endocrine functions and reproduction in pigs, but effects on health and behaviour are scarcely documented. The objective of this study was to evaluate the effects of different light intensities on behaviour, health and growth of growing-finishing pigs. An experiment was conducted on a commercial farm equipped with light-emitting diode-based luminaires creating four light intensity treatments: low (45 lux), medium (198 lux), high (968 lux) and spatial gradient of intensity (from 71 lux to 330 lux). Per treatment, 112 pigs were studied in two batches of eight pens. Once every two weeks behaviours such as exploration, positive and negative social interactions, play and abnormal behaviours were observed. Health issues were assessed weekly and included biting lesions, skin lesions, leg and respiratory disorders. The average daily gain over the experiment was calculated and after slaughter carcasses were inspected. Generalised linear mixed models were used for the analysis of behaviours, binary health scores, carcass abnormalities, ordinal logistic regression for multilevel health scores, and linear mixed models for average daily gain. Interactions between intensity and week were found for some behaviours (i.e., exploration, negative social interactions and abnormal behaviour) and health issues (i.e., tear stains, conjunctivitis, body lesions, bursitis and tail lesions). However, none of the treatments consistently outperformed another one. Light treatments did not affect pig growth and carcass abnormalities. These variable results support studies suggesting that pigs are adaptable to light intensities, and inconsistencies over weeks might have been caused by environmental factors that could not be controlled in a commercial farm setting. To conclude, tested light intensities had no clear effects on pig behaviour, health and growth.

Design considerations for patient-specific bone fixation plates: a literature review.

In orthopedic surgery, patient-specific bone plates are used for fixation when conventional bone plates do not fit the specific anatomy of a patient. However, plate failure can occur due to a lack of properly established design parameters that support optimal biomechanical properties of the plate.This review provides an overview of design parameters and biomechanical properties of patient-specific bone plates, which can assist in the design of the optimal plate.A literature search was conducted through PubMed and Embase, resulting in the inclusion of 78 studies, comprising clinical studies using patient-specific bone plates for fracture fixation or experimental studies that evaluated biomechanical properties or design parameters of bone plates. Biomechanical properties of the plates, including elastic stiffness, yield strength, tensile strength, and Poisson's ratio are influenced by various factors, such as material properties, geometry, interface distance, fixation mechanism, screw pattern, working length and manufacturing techniques.Although variations within studies challenge direct translation of experimental results into clinical practice, this review serves as a useful reference guide to determine which parameters must be carefully considered during the design and manufacturing process to achieve the desired biomechanical properties of a plate for fixation of a specific type of fracture.

Registration methods for surgical navigation of the mandible: a systematic review.

Image-to-patient registration in navigated mandibular surgery is complex due to the mobile nature of the mandible compared with other craniofacial bones. As a result, surgical navigation is rarely employed in the mandibular region. This systematic review provides an overview of the different registration methods that are used for surgical navigation of the mandible. A systematic search was performed in the MEDLINE Ovid, Scopus, and Embase databases on March 25, 2021. Search terms included synonyms for mandibular surgery, surgical navigation, and registration methods. Articles about navigated mandibular surgery, where the registration method was explicitly mentioned, were included. The database search yielded a total of 2952 articles, from which 81 articles remained for analysis. Four main registration methods were identified: point registration, surface registration, hybrid registration, and computer vision-based registration. The mobility of the mandible is accounted for by either keeping the mandible in a fixed position during preoperative imaging and surgery, or by tracking the mandibular movements. Although different registration methods are available for navigated mandibular surgery, there is always a trade-off between accuracy, registration time, usability, and invasiveness. Future studies should focus on testing the different methods in larger patient studies and should report the registration accuracy.

Assessment of the deep resection margin during oral cancer surgery: A systematic review.

The main challenge for radical resection in oral cancer surgery is to obtain adequate resection margins. Especially the deep margin, which can only be estimated based on palpation during surgery, is often reported inadequate. To increase the percentage of radical resections, there is a need for a quick, easy, minimal invasive method, which assesses the deep resection margin without interrupting or prolonging surgery. This systematic review provides an overview of technologies that are currently being studied with the aim of fulfilling this demand. A literature search was conducted through the databases Medline, Embase and the Cochrane Library. A total of 62 studies were included. The results were categorized according to the type of technique: 'Frozen Section Analysis', 'Fluorescence', 'Optical Imaging', 'Conventional imaging techniques', and 'Cytological assessment'. This systematic review gives for each technique an overview of the reported performance (accuracy, sensitivity, specificity, positive predictive value, negative predictive value, or a different outcome measure), acquisition time, and sampling depth. At the moment, the most prevailing technique remains frozen section analysis. In the search for other assessment methods to evaluate the deep resection margin, some technologies are very promising for future use when effectiveness has been shown in larger trials, e.g., fluorescence (real-time, sampling depth up to 6 mm) or optical techniques such as hyperspectral imaging (real-time, sampling depth few mm) for microscopic margin assessment and ultrasound (less than 10 min, sampling depth several cm) for assessment on a macroscopic scale.

Electromagnetic surgical navigation in patients undergoing mandibular surgery.

The purpose of this study was to evaluate the feasibility of electromagnetic (EM) navigation for guidance on osteotomies in patients undergoing oncologic mandibular surgery. Preoperatively, a 3D rendered model of the mandible was constructed from diagnostic computed tomography (CT) images. Cutting guides and patient specific reconstruction plates were designed and printed for intraoperative use. Intraoperative patient registration was performed using a cone beam CT scan (CBCT). The location of the mandible was tracked with an EM sensor fixated to the mandible. The real-time location of both the mandible and a pointer were displayed on the navigation system. Accuracy measurements were performed by pinpointing four anatomical landmarks and four landmarks on the cutting guide using the pointer on the patient and comparing these locations to the corresponding locations on the CBCT. Differences between actual and virtual locations were expressed as target registration error (TRE). The procedure was performed in eleven patients. TREs were 3.2 ± 1.1 mm and 2.6 ± 1.5 mm using anatomical landmarks and landmarks on the cutting guide, respectively. The navigation procedure added on average half an hour to the duration of the surgery. This is the first study that reports on the accuracy of EM navigation in patients undergoing mandibular surgery.

Evaluating the accuracy of resection planes in mandibular surgery using a preoperative, intraoperative, and postoperative approach.

In mandibular surgery, three-dimensionally printed patient-specific cutting guides are used to translate the preoperative virtually planned resection planes to the operating room. This study was performed to determine whether cutting guides are positioned according to the virtual plan and to compare the intraoperative position of the cutting guide with the resection performed. Nine patients were included. The exact positions of the resection planes were planned virtually and a patient-specific cutting guide was designed and printed. After surgical placement of the cutting guide, intraoperative cone beam computed tomography (CBCT) was performed. Postoperative CT was used to obtain the final resection planes. Distances and yaw and pitch angles between the preoperative, intraoperative, and postoperative resection planes were calculated. Cutting guides were positioned on the mandible with millimetre accuracy. Anterior osteotomies were performed more accurately than posterior osteotomies (intraoperatively positioned and final resection planes differed by 1.2±1.0mm, 4.9±6.6°, and 1.8±1.5°, respectively, and by 2.2±0.9mm, 9.3±9°, and 8.3±6.5° respectively). Differences between intraoperatively planned and final resection planes imply a directional freedom of the saw through the saw slots. Since cutting guides are positioned with millimetre accuracy compared to the virtual plan, the design of the saw slots in the cutting guides needs improvement to allow more accurate resections.

Utilization of a 3D printed dental splint for registration during electromagnetically navigated mandibular surgery.

PURPOSE: A dental splint was developed for non-invasive rigid point-based registration in electromagnetically (EM) navigated mandibular surgery. Navigational accuracies of the dental splint were compared with the common approach, that is, using screws as landmarks. METHODS: A dental splint that includes reference registration notches was 3D printed. Different sets of three points were used for rigid point-based registration on a mandibular phantom: notches on the dental splint only, screws on the mandible, contralateral screws (the side of the mandible where the sensor is not fixated) and a combination of screws on the mandible and notches on the dental splint. The accuracy of each registration method was calculated using 45 notches at one side of the mandible and expressed as the target registration error (TRE). RESULTS: Average TREs of 0.83 mm (range 0.7-1.39 mm), 1.28 mm (1.03-1.7 mm), 2.62 mm (1.91-4.0 mm), and 1.34 mm (1.30-1.39 mm) were found, respectively, for point-based registration based on the splint only, screws on the mandible, screws on the contralateral side only, and screws combined with the splint. CONCLUSION: For dentate patients, rigid point-based registration performs best utilizing a dental splint with notches. The dental splint is easy to implement in the surgical, and navigational, workflow, and the notches can be pinpointed and designated on the CT scan with high accuracy. For edentate patients, screws can be used for rigid point-based registration. However, a new design of the screws is recommended to improve the accuracy of designation on the CT scan.

Ultrasound aids in intraoperative assessment of deep resection margins of squamous cell carcinoma of the tongue.

We wanted to find out whether ultrasound (US) can be used to assess the deep resection margins after excision of squamous cell carcinoma (SCC) of the tongue, as intraoperative feedback on their condition might help to prevent them being too close. Resected specimens of cancers of the tongue from 31 patients with SCC of the tongue were suspended in US gel and scanned with a small 5-10MHz US probe. The tumour was readily visible and US could differentiate it from muscle tissue. The margin of normal tongue musculature surrounding the tumour was measured on the US images, and the minimal resection margin was noted and compared with that reported by the histopathologist. The mean (SD) deep resection margins measured on the US images differed by 1.1 (0.9) mm from those reported by the histopathologist (Pearson's correlation coefficient: 0.79, p<0.01). The US measurements took a maximum of five minutes. It is feasible to use US to assess resection specimens of SCC of the tongue as an adjunct to existing strategies (such as frozen section analysis) to help achieve the desired deep surgical margins. The method is easy to incorporate into surgical routine as it does not take long.

Tissue diagnosis during colorectal cancer surgery using optical sensing: an in vivo study.

BACKGROUND: In colorectal cancer surgery there is a delicate balance between complete removal of the tumor and sparing as much healthy tissue as possible. Especially in rectal cancer, intraoperative tissue recognition could be of great benefit in preventing positive resection margins and sparing as much healthy tissue as possible. To better guide the surgeon, we evaluated the accuracy of diffuse reflectance spectroscopy (DRS) for tissue characterization during colorectal cancer surgery and determined the added value of DRS when compared to clinical judgement. METHODS: DRS spectra were obtained from fat, healthy colorectal wall and tumor tissue during colorectal cancer surgery and results were compared to histopathology examination of the measurement locations. All spectra were first normalized at 800 nm, thereafter two support vector machines (SVM) were trained using a tenfold cross-validation. With the first SVM fat was separated from healthy colorectal wall and tumor tissue, the second SVM distinguished healthy colorectal wall from tumor tissue. RESULTS: Patients were included based on preoperative imaging, indicating advanced local stage colorectal cancer. Based on the measurement results of 32 patients, the classification resulted in a mean accuracy for fat, healthy colorectal wall and tumor of 0.92, 0.89 and 0.95 respectively. If the classification threshold was adjusted such that no false negatives were allowed, the percentage of false positive measurement locations by DRS was 25% compared to 69% by clinical judgement. CONCLUSION: This study shows the potential of DRS for the use of tissue classification during colorectal cancer surgery. Especially the low false positive rate obtained for a false negative rate of zero shows the added value for the surgeons. Trail registration This trail was performed under approval from the internal review board committee (Dutch Trail Register NTR5315), registered on 04/13/2015, https://www.trialregister.nl/trial/5175 .

The oral cavity tumor thickness: Measurement accuracy and consequences for tumor staging.

INTRODUCTION: In the 8th edition of the AJCC/UICC cancer staging system (AJCC8), the depth of invasion (DOI) of the oral cavity tumor is the discriminative factor in tumor staging over the previously used greatest dimension (GD). In order to obtain a complete representation of how accurate we stage oral cavity cancer clinically, we evaluated the accuracy of measurements of the tumor dimensions on ultrasound (US) and magnetic resonance (MR) imaging by comparing this with the histopathology as the "golden standard". Secondly, we compared the pathological tumor staging of these tumors according to the AJCC7 and AJCC8, to evaluate the effect of the incorporation of the DOI in the AJCC8. MATERIALS AND METHODS: In a retrospective analysis, including 85 oral cavity tumors, the GD and tumor thickness (TT) measured on US and MR, were compared to histopathology with a Pearson correlation coefficient (R) and a Bland-Altman plot. The tumors were staged according to both the AJCC7 and AJCC8. RESULTS: TT was more reliably measured with US (R = 0.67, limits of agreement = 10.7 mm), whereas GD was more reliably measured with MR (R = 0.69, limits of agreement = 25.7 mm). The AJCC8 staging resulted into a higher tumor stage in 21% of the cases, compared to the AJCC7. CONCLUSION: For preoperative tumor staging, the TT is best estimated by the use of US. The incorporation of DOI in the AJCC8 can result in a higher tumor stage in more than twenty percent of the patients, with an associated worse prognosis for the patient.

Identification and classification of components in flash pyrolysis oil and hydrodeoxygenated oils by two-dimensional gas chromatography and time-of-flight mass spectrometry.

Hydrodeoxygenated pyrolysis oils (HDO) are considered promising renewable liquid energy carriers. To gain insights in the various reaction pathways taking place during the hydrodeoxygenation reaction of pyrolysis oil, two-dimensional gas chromatography with time-of-flight mass spectrometric analyses (2D-GC-TOF-MS) was applied on the feedstock and product oil. Chromatographic parameters like injection temperature and column choice of the 1D-(2)D ensemble are discussed. Fractionation of the oils by hexane extraction was applied to show the distribution of analytes over the phases. Some 1000 and 2000 components in the pyrolysis and HDO oil, respectively could be identified and classified. The TOF-MS detection considerably improved the understanding of the molecular distribution over the 1D-(2)D retention time fields in the contour plot, in order to classify the analytes in functional groups. By group-type classification of the main components (>0.3% relative area), it was possible to characterize the oils by 250 and 350 analytes, respectively pyrolysis oil and HDO oil, describing 75% of the chromatographable fraction. The 2D-GC-TOF-MS method showed to be a useful and fast technique to determine the composition of (upgraded) pyrolysis oil and is potentially a very useful tool for exploratory catalyst research and kinetic studies. The 2D-GC-TOF-MS technique is not only useful for the chemical study as such, but also provides the basic knowledge for method transfer to a 2D-GC-FID (flame ionization detector) application.

The seven minute screen: a neurocognitive screening test highly sensitive to various types of dementia.

BACKGROUND: The seven minute screen (7MS) is a compilation of the temporal orientation test, enhanced cued recall, clock drawing, and verbal fluency. It has been shown to be useful for detecting Alzheimer's disease in a population of patients with memory complaints. OBJECTIVE: To assess the predictive validity of the 7MS for various types of dementia, and the influence of depression and other psychiatric conditions on 7MS scores. SETTING: Multicentre: secondary referral sites across the Netherlands. SUBJECTS: 542 patients with various types of dementia or depression, together with 45 healthy controls. RESULTS: Alzheimer's disease was diagnosed in 177 patients, other types of dementia in 164. The sensitivity of the 7MS for Alzheimer's disease was 92.9% with a specificity of 93.5%. For other types of dementia the sensitivity was 89.4% and the specificity 93.5%. Cognitive abnormalities were found in 71% of the patients with depression (n = 31). The mean (SD) duration of administration of the 7MS was 12.4 (4.6) minutes, range 8 to 22, depending on dementia severity. CONCLUSIONS: The 7MS is a useful screening tool for discriminating patients with dementia from cognitively intact patients. This not only applies to Alzheimer's disease but also to other types of dementia. Specificity with respect to depression was lower for the 7MS than for the MMSE.

Automated determination of fatty acid methyl ester and cis/trans methyl ester composition of fats and oils.

The determination of the fatty acid composition (as methyl esters, FAMEs) of fats and oils and their cis/trans (CTME) distribution requires a simple, but manual and time-consuming sample preparation. The so-called BF3 method is often the preferred procedure. Because FAME/CTME analyses are encountered very frequently in the food industry, an automated, robot-based alternative is proposed which uses the sodium methylate procedure. After sample weighing and the (manual) addition of heptane (2 min), a XYZ robotic autosampler is used for all remaining work, which includes reagent addition, agitation, sample settling and the final injection into the gas chromatograph (10 min). The performance of the sodium methylate and BF3 methods are compared by analysing some 30 oil and fat samples. The novel procedure is much faster (less than 15 min versus ca. 1 h) and manual sample handling is drastically decreased. The experimental results obtained with the two methods frequently are the same, while small differences can be explained by (known) differences of the two methods in the conversion of minor oil/fat constituents, such as free fatty acids, wax esters and sterol esters. In case of FAME analyses, a hot injection is to be preferred over a cold injection. The RSDs of the peak areas were 1.5% for the major fatty acids to 11% for peaks that were just above the noise level. The detection limit were approximately 0.03%.