Understanding the contagiousness of Covid-19 strains: A geometric approach

Protein-protein interaction occurs on surface patches with some degree of complementary geometric and chemical features. Building on this understanding, this study endeavors to characterize the spike protein of the SARS-CoV-2 virus at the morphological and geometrical levels in its Alpha, Delta, and Omicron variants. In particular, the affinity between different SARS-CoV-2 spike proteins and the ACE2 receptor present on the membrane of the human respiratory system cells is investigated. To achieve an adequate degree of geometrical accuracy, the 3D depth maps of the proteins in exam are filtered by developing an ad-hoc convolutional filter with a kernel implemented as a sphere of varying radius, simulating a ball rolling on the surface (similar to the 'rolling ball' filter). This ball ideally models a hypothetical molecule that could interface with the protein and is inspired by the geometric approach to macromolecule-ligand interactions proposed by Kuntz et al. in 1982. The aim is to mitigate the imperfections and to obtain a smoother surface that could be studied from a geometrical perspective for binding purposes. A set of geometric descriptors, borrowed from the 3D face analysis context is then mapped point-by-point onto protein depth maps. Following a feature extraction phase inspired by Histogram of Oriented Gradients and Local Binary Patterns, the final histogram features are used as input for a Support Vector Machine classifier to automatically classify the proteins according to their surface affinity, where a similarity in shape is observed between ACE2 and the spike protein of the SARS-CoV-2 Omicron variant. Finally, Root Mean Square Error analysis is used to quantify the geometrical affinity between the ACE2 receptor and the respective Receptor Binding Domains of the three SARS-CoV-2 variants, culminating in a geometrical explanation for the higher contagiousness of Omicron relative to the other variants under study.

Do facial soft tissue thicknesses change after surgeries correcting dental malocclusions? An intra- and inter-patient statistical analysis on soft-tissue thicknesses in BSSO + LFI surgeries

OBJECTIVES

The aim of this study was to analyse changes in facial soft tissue thickness (FSTT) after corrective surgeries for dental malocclusion. The correlation between body mass index (BMI) and sex of patients and their FSTT before undergoing surgery was analysed.

MATERIALS AND METHODS

Cone beam computed tomography of seventeen patients that underwent Le Fort I osteotomy in combination with bilateral sagittal split osteotomy were collected. Hard and soft tissue landmarks were selected basing on the interventions. FSTT were computed, and measurements from pre- to post-operative were compared. The relationship between FSTT, sex, and BMI was investigated.

RESULTS

Considering the comparison between pre- and post-operative measurements, any significant difference emerged (p > .05). The Pearson's correlation coefficient computed between BMI and the FSTT (pre-operative) showed a correlation in normal-weight patients; the region-specific analysis highlighted a stronger correlation for specific landmarks. Higher median values emerged for women than for men; the subset-based analysis showed that women presented higher values in the malar region, while men presented higher values in the nasal region.

CONCLUSIONS

The considered surgeries did not affect the FSTT of the patients; differences related to BMI and sex were found. A collection of FSTT mean values was provided for twenty landmarks of pre- and post-operative of female and male subjects.

CLINICAL RELEVANCE

This exploratory analysis gave insights on the behaviour of STT after maxillofacial surgeries that can be applied in the development of predictive methodologies for soft tissue displacements and to study modifications in the facial aspect of the patients.

Affective Virtual Reality: How to Design Artificial Experiences Impacting Human Emotions

Computer graphics is-in many cases-about visualizing what you cannot see. However, virtual reality (VR), from its beginnings, aimed at stimulating all human senses: not just the visual channel. Moreover, this set of multisensory stimuli allows users to feel present and able to interact with the virtual environment. In this way, VR aims to deliver experiences that are comparable to real-life ones in their level of detail and stimulation, intensity, and impact. Hence, VR is not only a means to see, but also to feel differently. With the spreading of VR technologies, there is a growing interest in using VR to evoke emotions, including positive and negative ones. This article discusses the current possibilities and the authors' experience collected in the field in trying to elicit emotions through VR. It explores how different design aspects and features can be used, describing their contributions and benefits in the development of affective VR experiences. This work aims at raising awareness of the necessity to consider and explore the full design space that VR technology provides in comparison to traditional media. Additionally, it provides possible tracks of VR affective applications, illustrating how they could impact our emotions and improve our life, and providing guidelines for their development.

Malar augmentation with zygomatic osteotomy in orthognatic surgery: Bone and soft tissue changes threedimensional evaluation

BACKGROUND

The aim of this prospective study is to objectively assess 3D soft tissue and bone changes of the malar region by using the malar valgization osteotomy in concomitant association with orthognatic surgery.

MATERIALS AND METHODS

From January 2015 to January 2018, 10 patients who underwent single stage bilateral malar valgization osteotomy in conjunction with maxillo-mandibular orthognatic procedures for aesthetic and functional correction were evaluated. Clinical and surgical reports were collected and patient satisfaction was evaluated with a VAS score. For each patient, maxillofacial CT-scans were collected 1 month preoperatively (T0) and 6 months after the operation (T1). DICOM data were imported and elaborated in the software MatLab, which creates a 3D soft tissue model of the face. 3D Bone changes were assessed importing DICOM data into iPlan (BrainLAB 3.0) software and the superimposition process was achieved using autofusion. Descriptive statistical analyses were obtained for soft tissue and bone changes.

RESULTS

Considering bone assessment the comparison by superimposition between T0 and T1 showed an increase of the distance between bilateral malar prominence (Pr - Pl) and a slight forward movement (87,65 ± 1,55 to 97,60 ± 5,91); p-value 0.007. All of the patients had improvement of α angle, ranging from 36,30 ± 1,70 to 38,45 ± 0,55, p-value 0,04 (αr) and 36,75 ± 1,58 to 38,45 ± 0,35; p-value 0,04 (αl). The distance S increased from 78,05 ± 2,48 to 84,2 ± 1,20; p-value 0,04 (Sr) and 78,65 ± 2,16 to 82,60 ± 0,90 (Sl); p-value 0,03. Considering the soft tissue, the comparison by superimposition between T0 and T1 showed an antero-lateral movement (p-value 0.008 NVL; p-value 0.001 NVR) of the malar bone projection together with an increase in width measurements (p-value 0,05 VL; p-value 0,01 VR). Angular measurement confirmed the pattern of the bony changes (p-value 0.034 αL; p-value 0,05 αR).

CONCLUSION

The malar valgization osteotomy in conjunction with orthognatic surgery is effective in improving zygomatic projection contributing to a balanced facial correction in midface hypoplasia.3D geometrical based volume and surface analysis demonstrate an increase in transversal and forward direction. The osteotomy can be safely performed in conjunction with orthognatic procedures.

A new method for protein characterization and classification using geometrical features for 3D face analysis: An example of tubulin structures

This article reports on the results of research aimed to translate biometric 3D face recognition concepts and algorithms into the field of protein biophysics in order to precisely and rapidly classify morphological features of protein surfaces. Both human faces and protein surfaces are free-forms and some descriptors used in differential geometry can be used to describe them applying the principles of feature extraction developed for computer vision and pattern recognition. The first part of this study focused on building the protein dataset using a simulation tool and performing feature extraction using novel geometrical descriptors. The second part tested the method on two examples, first involved a classification of tubulin isotypes and the second compared tubulin with the FtsZ protein, which is its bacterial analog. An additional test involved several unrelated proteins. Different classification methodologies have been used: a classic approach with a support vector machine (SVM) classifier and an unsupervised learning with a k-means approach. The best result was obtained with SVM and the radial basis function kernel. The results are significant and competitive with the state-of-the-art protein classification methods. This leads to a new methodological direction in protein structure analysis.

QFD 3D: a new C-shaped matrix diagram quality approach

Purpose

– Quality function deployment (QFD) is a worldwide-known, design for quality approach, which gathers several design quality methods. Among them, the House of Quality (HoQ) correlates the Voice of Customer and the Voice of Company thanks to L-shaped (2D) Matrix Diagrams (MDs). This paper theorizes, as logically possible, the extension from a bi-dimensional representation (a customer and a provider) to a higher N-dimensional representational freedom without altering the typical QFD’s customer-provider posture. The purpose of this paper is to present QFD 3D: the extension of the Relationship MD in the HoQ toward a third dimension (two customers and a provider or two providers and a customer).

Design/methodology/approach

– The proposed method is based on an existing well-known quality management tool such as MDs. The authors extend its representational capability by substituting the current L-shaped MDs (2D) with C-shaped ones (3D). The mathematical validity of this extension is described to demonstrate the correctness of the approach.

Findings

– The paper presents the logical validity and a case study concerning a three-dimensional extension of the Relationship MD in the HoQ, typical of the QFD approach.

Research limitations/implications

– The results are limited to a three-dimensional extension. Situations where more than three actors are simultaneously involved are theoretically possible, but they are out of the scope of the current research. The difficulty in manipulating 3D representations on traditional supporting tools will be completely reversed on new computer-supported tools. The proposed method is meant to be a useful and efficient instrument for correlating the needs and the services in multi-actors-based scenario, using a QFD design quality approach fueled by IT support tools.

Practical implications

– This paper can be used as guideline for further researches on N-dimensional extensions of HoQ. The proposed method can be used in a scenario based on the Triple Helix of Innovation. It gives a clear correlation between different needs and services, facilitating the decision-making process and the constitution of a more comprehensive view of the scenario under a quality management approach.

Originality/value

– Thousands of articles propose different QFD case studies all based on a bi-dimensional correlation between a customer and a provider. This paper proposes a method to extend the pertinence of QFD to scenarios where more than two actors are simultaneously correlated. Considering in particular three actors, the resulting three-dimensional Relationship MD in the HoQ is a totally new design quality tool for correlating customers’ needs and providers’ services. This can result in a significant gain of time and representational ability for quality managers who have to correlate multiple customers with a service provider and conversely a customer to multiple service providers. This approach open the doors for new QFD tools fueled by IT.

3D landmarking in multiexpression face analysis: a preliminary study on eyebrows and mouth

The application of three-dimensional (3D) facial analysis and landmarking algorithms in the field of maxillofacial surgery and other medical applications, such as diagnosis of diseases by facial anomalies and dysmorphism, has gained a lot of attention. In a previous work, we used a geometric approach to automatically extract some 3D facial key points, called landmarks, working in the differential geometry domain, through the coefficients of fundamental forms, principal curvatures, mean and Gaussian curvatures, derivatives, shape and curvedness indexes, and tangent map. In this article we describe the extension of our previous landmarking algorithm, which is now able to extract eyebrows and mouth landmarks using both old and new meshes. The algorithm has been tested on our face database and on the public Bosphorus 3D database. We chose to work on the mouth and eyebrows as a separate study because of the role that these parts play in facial expressions. In fact, since the mouth is the part of the face that moves the most and affects mainly facial expressions, extracting mouth landmarks from various facial poses means that the newly developed algorithm is pose-independent.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

A pose-independent method for 3D face landmark formalization

Recently, 3D landmark extraction has been widely researched and experimented in medical field, for both corrective and aesthetic purposes. Automation of these procedures on three-dimensional face renderings is something desirable for the specialists who work in this field. In this work we propose a new method for accurate landmark localization on facial scans. The method relies on geometrical descriptors, such as curvatures and Shape Index, for computing candidate and initial points, and on a statistical model based on Procrustes Analysis and Principal Component Analysis, which is fitted to candidate points, for extracting the final landmarks. The elaborated method is independent on face pose.

[Definition and validation of a comfort index calculation method for office seats]

BACKGROUND

Among its other required features, a highly comfortable chair should adapt its contact surfaces, namely the seat and the back rest, to the shape of the body of the person sitting on it. However, "comfort" is not usually perceived as an absolute value, but is derived from a subjective comparison between two or more chairs.

OBJECTIVES

The purpose of this research was the definition of an objective comfort index (IC), i.e., derived from instrumental measurements, and which would also represent an absolute comfort value.

METHODS

Analytical evaluation of the distribution of body weight, by means of a barometric matrix, shows that a comfortable chair tends to minimize peak and average values of pressure at the level of the contact areas located between the body and the seat and the back of the chair. To define a comparison parameter for determining an absolute comfort value, a reference chair (SDR) was developed. The seat and the back of this chair are rigid, with poor compliance. A comfort value of zero was, by definition, assigned to this chair. Therefore, the Comfort index (IC) was obtained by the mathematical calculation of the ratios of averages, peaks and gradients of pressure, appropriately weighted, and the corresponding values measured on the tested chair and on the SDR.

RESULTS

It is shown that the anthropometric characteristics of each subject are irrelevant to the assessment of the IC, which depends only on the compliance characteristics of the seat and back surfaces of the tested chair

CONCLUSIONS

IC can be improved through analysis of a larger number of seats, which would thus constitute the basis for the use of an objective evaluation of seating comfort.

[Strategies to face the shortage of nurses in 11 health settings: descriptive analysis]

A survey on the perceived severity and criteria for defining the nursing shortage was made by interviewing with a semistructured questionnaire 11 nurses responsible for nursing services of 11 Italian hospitals and districts. The questionnaire was administered by interview. Ten hospitals suffer a medium-severe nursing shortage. The main solutions adopted to overcome the nursing shortage are: the closure of wards, the merge of wards, with comparable patients; the employment of support personnel; the mobility of nursing personnel, whereby nurses change wards and are move where they are most needed; modification of shifts. Interestingly, criteria for defining the nursing shortage vary from hospital to hospital, but they are not based on objective data (c.g. number of "missing" nurses). The payment of overtime hours is also different, ranging from 20 to 35 dollars/hour. Since the shortage of nurses will last for the next 5-8 years, a study of criteria for assessing it, of solutions adopted and of their effectiveness is pivotal for gaining a better understanding of the problem.