bluuebunny/crossref_metadata_2025 huggingface dataset:
DEVELOPMENT OF A BONE-ON-A-CHIP MICROFLUIDIC DEVICE AS A MODEL OF OSTEOPOROSIS
Authors: Lipreri M.V. , Pasquarelli A. , Scelfo D. , Baldini N. , Avnet S.
Published: January 2024

Osteoporosis is a progressive, chronic disease of bone metabolism, characterized by decreased bone mass and mineral density, predisposing individuals to an increased risk of fractures. The use of animal models, which is the gold standard for the screening of anti-osteoporosis drugs, raises numerous ethical concerns and is highly debated because the composition and structure of animal bones is very different from human bones. In addition, there is currently a poor translation of pre-clinical efficacy in animal models to human trials, meaning that there is a need for an alternative method of screening and evaluating new therapeutics for metabolic bone disorders, in vitro.

The aim of this project is to develop a 3D Bone-On-A-Chip that summarizes the spatial orientation and mutual influences of the key cellular components of bone tissue, in a citrate and hydroxyapatite-enriched 3D matrix, acting as a 3D model of osteoporosis. To this purpose, a polydimethylsiloxane microfluidic device was developed by CAD modelling, stereolithography and replica molding. The device is composed by two layers: (i) a bottom layer for a 3D culture of osteocytes embedded in an osteomimetic collagen-enriched matrigel matrix with citrate-doped hydroxyapatite nanocrystals, and (ii) a upper layer for a 2D perfused co-culture of osteoblasts and osteoclasts seeded on a microporous PET membrane.

Cell vitality was evaluated via live/dead assay. Bone deposition and bone resorption was analysed respectively with ALP, Alizarin RED and TRACP staining. Osteocytes dendrite expression was evaluated via immunofluorescence. Subsequently, the model was validated as drug screening platform inducing osteocytes apoptosis and administrating standard anti-osteoporotic drugs.

This device has the potential to substitute or minimize animal models in pre-clinical studies of osteoporosis, contributing to pave the way for a more precise and punctual personalized treatment.
QUANTIFYING VARIABILITY IN DAILY ACCELERATIONS RECORDED BY INERTIAL SENSORS IN HEALTHY INDIVIDUALS: IMPLICATIONS FOR GAIT MEASUREMENT IN FREE-LIVING ENVIRONMENTS
Authors: Ghaffari A. , Rasmussen J. , Kold S. , Rahbek O.
Published: January 2024

Gait measurements can vary due to various intrinsic and extrinsic factors, and this variability becomes more pronounced using inertial sensors in a free-living environment. Therefore, identifying and quantifying the sources of variability is essential to ensure measurement reliability and maintain data quality.

This study aimed to determine the variability of daily accelerations recorded by an inertial sensor in a group of healthy individuals. Ten participants, four males and six females, with a mean age of 50 years (range: 29–61) and BMI of 26.9 kg/m2 (range: 21.4–36.8), were included. A single accelerometer continuously recorded lower limb accelerations over two weeks. We extracted and analyzed the accelerations of three consecutive strides within walking bouts if the time difference between the bouts was more than two hours. Multivariate mixed-effects modeling was performed on both the discretized acceleration waveforms at 101 points (0–100) and the harmonics of the signals in the frequency domain to determine the variance components for different subjects, days, bouts, and steps as the random effect variables. Intraclass correlation coefficients (ICCs) were calculated for between-day, between-bout, and between-step comparisons.

The results showed that the ICCs for the between-day, between-bout, and between-step comparisons were 0.73, 0.82, 0.99 for the vertical axis; 0.64, 0.75, 0.99 for the anteroposterior axis; and 0.55, 0.96, 0.97 for the mediolateral axis. For the signal harmonics, the respective ICCs were 0.98, 0.98, 0.99 for the vertical axis; 0.54, 0.93, 0.98 for the anteroposterior axis; and 0.69, 0.78, 0.95 for the mediolateral axis.

Overall, this study demonstrated that accelerations recorded continuously for multiple days in a free-living environment exhibit high variability, mainly between days, and some variability arising from differences between walking bouts during different times within days. However, reliable and repeatable gait measurements can be obtained by identifying and quantifying the sources of variability.
A MODEL TO EXPLORE INTERVERTEBRAL DISC CELL ACTIVITY IN ADVERSE BIOCHEMICAL ENVIRONMENTS
Authors: Tseranidou S. , Bermudez-Lekerika P. , Segarra-Queralt M. , Gantenbein B. , Maitre C.Le , Piñero J. , Noailly J.
Published: January 2024

Intervertebral disc (IVD) degeneration (IDD) involves imbalance between the anabolic and the catabolic processes that regulate the extracellular matrix of its tissues. These processes are complex, and improved integration of knowledge is needed. Accordingly, we present a nucleus pulposus cell (NPC) regulatory network model (RNM) that integrates critical biochemical interactions in IVD regulation and can replicate experimental results. The RNM was built from a curated corpus of 130 specialized journal articles. Proteins were represented as nodes that interact through activation and inhibition edges. Semi-quantitative steady states (SS) of node activations were calculated. Then, a full factorial sensitivity analysis (SA) identified which out of the RNM 15 cytokines, and 4 growth factors affected most the structural proteins and degrading enzymes. The RNM was further evaluated against metabolic events measured in non-healthy human NP explant cultures, after 2 days of 1ng/ml IL-1B catabolic induction. The RNM represented successfully an anabolic basal SS, as expected in normal IVD. IL-1B was able to increase catabolic markers and angiogenic factors and decrease matrix proteins. Such activity was confirmed by the explant culture measurements. The SA identified TGF-β and IL1RA as the two most powerful rescue mediators. Accordingly, TGFβ signaling-based IDD treatments have been proposed and IL-1RA gene therapy diminished the expression of proteases. It resulted challenging to simulate rescue strategies by IL-10, but interestingly, IL-1B could not induce IL-10 expression in the explant cultures. Our RNM was confronted to independent in vitro measurements and stands for a unique model, to integrate soluble protein signaling and explore IDD.

Acknowledgements: European Commission (Disc4All-ITN-ETN-955735)
COMMERCIALLY PURE (CP-TI) TITANIUM MEDICAL IMPLANT PRODUCTION USING LASER POWDER BED FUSION (L-PBF) TECHNOLOGY
Authors: Depboylu F.N. , Yasa E. , Poyraz Ö. , Korkusuz F.
Published: January 2024

Decreasing the bulk weight without losing the biomechanical properties of commercial pure titanium (Cp-Ti) medical implants is now possible by using Laser Powder Bed Fusion (L-PBF) technology. Gyroid lattice structures that have precious mechanical and biological advantages because of similarity to trabecular bone. The aim of the study was to design and develop L-PBF process parameter optimization for manufacturing gyroid lattice Cp-Ti structures. The cleaning process was then optimized to remove the non-melted powder from the gyroid surface without mechanical loss.

Gyroid cubic designs were created with various relative densities by nTopology. L-PBF process parameter optimization was progressed using with Cp-Ti (EOS TiCP Grade2) powder in the EOS M290 machine to achieve parts that have almost full dense and dimensional accuracy. The metallography method was made for density. Dimensional accuracy at gyroid wall thicknesses was investigated between designed and manufactured via stereomicroscope, also mechanical tests were applied with real time experiment and numerical analysis (ANSYS). Mass loss and strut thickness loss were investigated for chemical etching cleaning process.

Gyroid parts had 99,5% density. High dimensional accuracy was achieved during L-PBF process parameters optimization. Final L-PBF parameters gave the highest 19% elongation and 427 MPa yield strength values at tensile test. Mechanical properties of gyroid were controlled with changing relative density. A minute chemical etching provided to remove non-melted powders.

Compression test results of gyroids at numerical and real-time analysis gave unrelated while deformation behaviors were compatible with each other. Gyroid Cp-Ti osteosynthesis mini plates will be produced with final L-PBF process parameters. MTT cytotoxicity test will be characterized for cell viability.

Acknowledgements This project is granted by TUBITAK (120N943). Feza Korkusuz MD is a member of the Turkish Academy of Sciences (TÜBA).
DEVELOPING REGENERATION THERAPIES FOR THE INTERVERTEBRAL DISC
Authors: Gantenbein B.
Published: January 2024

Stem cell therapy for the intervertebral disc (IVD) is highly debated but holds great promises. From previous studies, it is known that notochordal cells are highly regenerative and may stimulate other differentiated cells to produce more matrix. Lately, a particular tissue-specific progenitor cell population has been identified in the centre of the intervertebral disc (IVD. The current hope is that these nucleus pulposus progenitor cells (NPPC) could play a particular role in IVD regeneration.

Current evidence confirms the presence of these cells in murine, canine, bovine and in the human fetal/surgical samples. Noteworthy, one of the main markers to identify these cells, i.e., Tie2, is a typical marker for endothelial cells. Thus, it is not very clear what their origin and their role might be in the context of developmental biology. In human surgical specimens, their presence is, even more, obscured depending on the donor's age and the condition of the IVD and other yet unknown factors.

Here, I revisit the recent literature on regenerative cells identified for the IVD in the past decades. Current evidence how these NPPC can be isolated and detected in various species and tissues will be recapitulated. Future directions will be provided on how these progenitor cells could be used for regenerative medicine and tissue engineering.
PROTO-ADVANCED PERSONALIZED THERAPIES FOR OSTEOARTHRITIS
Authors: Maleitzke T.
Published: January 2024

Osteoarthritis (OA) is the most common joint disease, affecting approximately 16% of the adult population worldwide. The chronic inflammation in the joint leads to the breakdown of cartilage, which leads to permanent pain and limitations in everyday life at an early stage of the disease. To date, there is no therapy that can interrupt the inflammatory state or reverse cartilage damage. The PROTO consortium (funded by the EU Horizon Europe program, Grant 101095635) aims to prevent the development of OA by correcting a pathological biomechanical pattern by a digital training intervention and to treat early stage OA with an innovative allogeneic cell therapy.
Effect of Non-Invasive Brain Stimulation on Sleep and Sleep Disorders
Authors: Byun Jung-Ick , Shin Won Chul , Jung Ki-Young
Published: January 2024

Non-invasive brain stimulation (NIBS), including transcranial magnetic and electrical stimulations, has recently been used to modulate sleep and treat sleep disorders. Herein, we reviewed studies that used NIBS to modulate sleep in healthy populations or patients with sleep disorders. Repetitive transcranial magnetic stimulation enhanced sleep slow oscillations and consistently improved subjective symptoms in patients with insomnia and restless legs syndrome. Transcranial electrical stimulation also increased slow-wave sleep in healthy populations and improved subjective sleep symptoms in patients with insomnia. Individualized NIBS and other NIBS techniques may be promising for treating sleep disorders, and future studies are warranted to determine optimal stimulation parameters and evaluate their long-term safety.
Tubercular Osteomyelitis Mimic Ewing’s Sarcoma
Authors:   Department of Orthopaedic Surgery, Tata motors hospital, Jamshedpur, Jharkhand, India., Pavan Sudarshan , Arvind Arvind ,   Department of Orthopaedic Surgery, Tata motors hospital, Jamshedpur, Jharkhand, India., Arora Aayush ,   Department of Orthopaedic Surgery, Tata motors hospital, Jamshedpur, Jharkhand, India., Singh Guruchetan ,   Department of Orthopaedic Surgery, Tata motors hospital, Jamshedpur, Jharkhand, India.
Published: January 2024

Introduction: Ewing’s sarcoma in children is an extremely rare malignant tumor that is frequently challenging to identify. In addition to its rarity in young children, Ewing’s sarcoma can resemble an infectious disease, contributing to diagnostic delay. Both conditions have similar presenting symptoms, such as general weakness, pain, and fever. Case Report: We present a case of a 13-year-old girl with pain over the right distal humerus for 2 months. X-ray findings showed lesions over the distal humerus which led to a differential diagnosis of osteomyelitis and Ewing’s sarcoma. The patient underwent bone biopsy and was diagnosed with tuberculous osteomyelitis and was managed conservatively in the form of antituberculosis treatment. Conclusion: For distinguishing Ewing’s sarcoma from osteomyelitis, imaging modalities can be unreliable, and these patients require a higher diagnostic yield in the form of a bone biopsy for greater accuracy. Keywords: Osteomyelitis, Ewing’s sarcoma, young children.
Alkaptonuria in an Elderly Presenting with Asynchronous Rupture of both Quadriceps Tendons and Chronic Kidney Failure: Case Report and Literature Review
Authors:   Department of Orthopaedics, King Saud Medical City, Riyadh, Saudi Arabia., Issa Ahmed M Al , Alsager Ghadeer A ,   Department of Orthopaedics, King Saud Medical City, Riyadh, Saudi Arabia.
Published: January 2024

Introduction: Alkaptonuria (AKU) is a rare autosomal-recessive multisystemic disease. It is caused by a mutant homogentisate dioxygenase coding gene, leading to the acclamation of homogentisic acid (HGA), hence systemic manifestations. Renal manifestations and tendon rupture are rarely reported. Case Report: We report a 60-year-old male with chronic kidney disease for over a decade who was initially misdiagnosed with ankylosing spondylitis and rheumatoid arthritis. Later on, the patient presented to our institute with a non-synchronized (8 years) acute quadriceps tendon rupture. Conclusion: Physicians should be aware of the importance of prophylactic measures in the management of AKU, which is mainly medical management, to reduce the accumulation of HGA in the body. We further emphasize this point to reduce the incidence of subsequent tendon ruptures, as it significantly affects the quality of life. Keywords: Alkaptonuria, kidney failure, tendon, rupture, quadriceps tendon.
Total Hip Arthroplasty in Ochronotic Arthropathy: A Case Report
Authors:   Department of Orthopaedics, Sarvodaya Hospital Research Centre, Robotic Joint Replacement Unit, Sector 8, Faridabad, Haryana, India., Bhattacharjee Sujoy , Ahlawat Akhil ,   Department of Orthopaedics, Sarvodaya Hospital Research Centre, Robotic Joint Replacement Unit, Sector 8, Faridabad, Haryana, India., Prasad Avijeet ,   Department of Orthopaedics, Sarvodaya Hospital Research Centre, Robotic Joint Replacement Unit, Sector 8, Faridabad, Haryana, India., Das Rajib Kumar ,   Department of Orthopaedics, Sarvodaya Hospital Research Centre, Robotic Joint Replacement Unit, Sector 8, Faridabad, Haryana, India.
Published: January 2024

Introduction: Total hip arthroplasty (THA) is a common procedure used to treat various hip conditions. However, patients with ochronotic arthropathy, a rare genetic disorder characterized by the abnormal accumulation of homogentisic acid, are at a higher risk of post-surgical dislocation and instability due to poor bone quality and joint degeneration. Case Report: This case study features a 52-year-old male patient diagnosed with ochronotic arthropathy who underwent bilateral THA with the use of a dual mobility cup (DMC). Ochronotic arthropathy had caused significant joint degeneration and stiffness, leading to considerable functional impairment. Conclusion: The application of a DMC in THA for patients with ochronotic arthropathy has shown promising outcomes. The DMC offers increased range of motion and improved stability, effectively reducing the risk of post-surgical dislocation and implant failure. This case study highlights the potential of DMC as a viable solution for addressing the challenges posed by poor bone quality in patients with ochronotic arthropathy undergoing THA. Keywords: Total hip arthroplasty, ochronotic arthropathy, dislocation, dual mobility cup, range of motion.
Management of Thrombosis of the External Iliac Artery during Total Hip Arthroplasty – A Case Report
Authors:   Department of Orthopaedics, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India,, Patro Bishnu Prasad , Jeyaraman Madhan ,   Department of Orthopaedics, ACS Medical College and Hospital, Dr. MGR Educational and Research Institute, Chennai, Tamil Nadu, India,, Dash Rashmi Ranjan ,   Department of Orthopaedics, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India,, Sathia Siddhartha ,   Department of Cardiothoracic Vascular Surgery, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India.
Published: January 2024

Introduction: Vascular injury following total hip arthroplasty (THA) is uncommon but can lead to loss of life or limb. External iliac and common femoral arteries are commonly injured during THA. Case Report: We report a case of thrombosis of the external iliac and femoral artery during THA in a mid-60-year female patient with 15-year-old neglected fracture neck of the femur. Six hours following THA through Harding’s approach, a feeble pulse was palpated in the operated limb. Ischemia of the limb led to sciatic nerve palsy and foot drop in the operated limb, which was intact following surgery. Computed tomography angiography confirmed thrombosis of the external iliac and femoral artery. Removal of thrombosis with the use of a Fogarty catheter could save the limb and lead to recovery of foot drop. Early detection of pulselessness and timely intervention in the post-operative period was the cornerstone of this case report. Conclusion: Vascular injury during THA though rare but cannot be ruled out completely. Early diagnosis with a stringent post-operative protocol and timely intervention would be the cornerstone of the management of any vascular injury following THA. Keywords: Thrombosis, arthroplasty, external iliac artery, angiography.
Bilateral Hoffa Fractures of the Medial Femoral Condyles: A Case Report and Review of the Literature
Authors:   Department of Orthopedics, General University Hospital of Patras, Patras 26504, Greece,, Kouzelis Antonios , Argyropoulou Evangelia ,   Department of Orthopedics, General University Hospital of Patras, Patras 26504, Greece,, Stavros Balasis ,   Department of Plastic Surgery, General University Hospital of Patras, Patras 26504, Greece., Papagiannis Spyridon ,   Department of Orthopedics, General University Hospital of Patras, Patras 26504, Greece,, Antzoulas Panagiotis ,   Department of Orthopedics, General University Hospital of Patras, Patras 26504, Greece,, Gliatis John ,   Department of Orthopedics, General University Hospital of Patras, Patras 26504, Greece,
Published: January 2024

Introduction: Intra-articular distal femoral fractures in the coronal plane, widely described as Hoffa fractures, are a rare entity. Lateral femoral condyles are mostly affected, while diagnosis can be challenging. Bilateral medial femoral condyle fractures are exceedingly scarce, with only one case being published in recent literature. Case Report: We present a case of a white 65-year-old man with bilateral medial femoral condyle Hoffa fractures caused by a crush injury. The patient was treated operatively by two different teams operating simultaneously on both sides, with good clinical and radiological outcomes after a follow-up period of 3 months. Conclusion: A literature review was conducted to analyze the potential mechanism of injury, diagnostic methods, and therapeutic approach. Bilateral medial Hoffa fractures are rare injuries concerning the orthopedic trauma field and this is the first case described, that was treated operatively with good functional outcomes. Keywords: Hoffa fractures, distal femur fractures, bilateral medial condyles, trauma.
Angioleiomyoma in a 54-year-old Female: A Case Report of Distal Leg Tumor and Review of the Literature
Authors:   Department of Orthopedics, St Joseph’s Hospital, Karuvanchal, Kannur, Kerala, India,, Mohan Sandeep , Krishnan Rahul ,   Department of Orthopedics, Co-operative Hospital Taliparamba, Kannur, Kerala, India.
Published: January 2024

Introduction: Angioleiomyomas are rare benign tumors originating from smooth muscle cells of blood vessels. Although they can occur in various anatomical locations, angioleiomyomas of the distal leg are relatively uncommon. Due to its clinical resemblance to other soft-tissue tumors, misdiagnosis can occur leading to inadequate treatment. Case Report: We present a case of angioleiomyoma in a 54-year-old female who presented with a palpable mass in her distal leg. The tumor was surgically excised, and histopathological examination confirmed the diagnosis of angioleiomyoma. In this article, we discuss the clinical presentation, diagnostic evaluation, and management of angioleiomyoma, with a focus on distal leg tumors. Furthermore, we provide a comprehensive review of the existing literature on angioleiomyomas, emphasizing findings and treatment outcomes reported in previous studies. Conclusion: Angioleiomyomas are uncommon soft-tissue tumors that can mimic other more common lesions such as ganglion cysts. Hence, diagnosis requires a high index of suspicion. Surgical excision is the treatment of choice for angioleiomyoma. Complete resection is generally curative, with a low rate of recurrence. Keywords: Angioleiomyoma, distal leg, surgical excision, review of literature.
Neglected Elbow Dislocation leading to Ankylosis of Elbow: A Case Report
Authors:   Department of Orthopaedic Surgery, HOSMAT Hospital, Bengaluru, Karnataka, India,, Pai Satvik N , Jeyaraman Naveen ,   Department of Orthopaedics, ACS Medical College and Hospital, Dr MGR Educational and Research Institute, Chennai, Tamil Nadu, India,, Jayakumar Tarun ,   Department of Orthopaedics, KIMS – Sunshine Hospital, Hyderabad, Telangana, India., Jeyaraman Madhan ,   Department of Orthopaedics, ACS Medical College and Hospital, Dr MGR Educational and Research Institute, Chennai, Tamil Nadu, India,
Published: January 2024

Introduction: Neglected elbow dislocation is defined as a dislocation that is present for 3 weeks or longer. There is no available literature on neglected elbow dislocations, leading to ankylosis of the elbow joint. Case Report: A 17-year-old female sustained a road traffic accident. Anteroposterior and lateral view radiographs of the forearm were done and deemed to be normal at another hospital. Six months after the injury, she presented to us with complaints of absent elbow movements. Examination revealed the elbow to be fixed in 30° of flexion. Radiographs of the elbow revealed an ankylosis of the ulnohumeral articulation in an abnormal position. Conclusion: This case demonstrates that neglected elbow dislocations can lead to ankylosis of the joint. It also shows how radiographs of the forearm are inadequate to assess for elbow dislocations even if the elbow region is covered in the radiograph. Keywords: Elbow, dislocation, ankylosis, ulnohumeral.
MODAL BEHAVIOUR OF LONGITUDINALLY PERFORATED NANOBEAMS
Authors:   National Centre for Studies and Integrated Research on Building (CNERIB), Souidania, Algiers 16097, Algeria, Ziou Hassina , Guenfoud Mohamed ,   University of Guelma, faculty of science and technology, Department of Civil and Hydraulic Engineering, BP 401 Guelma 24000, Algeria
Published: January 2024

Nano-electro-mechanical systems (NEMS) require perforated beams for structural integrity. Hole sizes, hole numbers, and scale effects need to be modelled appropriately in their design. This paper presents a new finite element model to investigate the modal behaviour of longitudinally perforated nanobeams (LPNBs) using the classical Euler–Bernoulli beam theory. A symmetric array of holes arranged parallel to the length direction of the beam with equal spacing was assumed for the perforation. The non-local Eringen’s differential form was used to incorporate the nanoscale sizes. The accuracy of the proposed model was verified by comparing the obtained results with the available analytical solutions for fully filled nanobeams. The effects of aspect ratios, non-local parameters, boundary conditions, and perforation characteristics on the modal behaviour of LPNBs were investigated. The non-local parameter reduced the natural frequency owing to a decrease in the stiffness of the structures. However, the perforation filling ratio led to higher values of the fundamental frequency. Furthermore, compared with other boundary conditions, clamped–clamped boundary conditions demonstrated the best performance in terms of the maximum frequency.
PRODUCTION OF SELF-HEALING MORTAR USING BACTERIAL SPORES ENCAPSULATED WITH JUTE FIBRE
Authors:   Bursa Technical University, Faculty of Engineering and Natural Sciences, Department of Civil Engineering, 152 Evler Street, Yıldırım Bayezid Campus, 16320, Bursa, Turkey, Yıldırım Musa , Özhan Hacer Bilir ,   Bursa Technical University, Faculty of Engineering and Natural Sciences, Department of Civil Engineering, 152 Evler Street, Yıldırım Bayezid Campus, 16320, Bursa, Turkey, ÖZ Hilal Girgin ,   Bursa Technical University, Faculty of Engineering and Natural Sciences, Department of Bioengineering, 152 Evler Street, Yıldırım Bayezid Campus, 16320, Bursa, Turkey
Published: January 2024

Cement-based composites have various advantages such as low cost, easy shaping, and high compressive strength. Therefore, they are widely used in the construction industry. However, their brittle structure makes them prone to cracking, which must be repaired promptly to avoid possible loss of strength and durability and ultimate structural failures. Microbially-induced calcite precipitation (MICP) offers an effective method for healing these cracks. Unlike other treatments, MICP method is a natural and environment-friendly option for self-healing of cracks. However, bacteria can be damaged by cement and mechanical impacts; therefore, encapsulation is necessary to protect them. Encapsulation in fibres is a simpler and more cost-effective method than the other techniques. This study tested the effectiveness of encapsulating Bacillus megaterium spores in jute fibres and added them to cement-based mortars. Different nutrient supplements were used, and physical analyses and compressive strength tests were conducted on 28-day cured cube specimens. Present findings revealed that Bacillus megaterium-type bacteria encapsulated in jute fibres improved the compressive strength recovery and healed the loading-induced cracks.
SLAM medical imaging enabled by a pre-chirp and gain jointly managed Yb-fiber laser
Authors: Xing Yuting , Chen Runzhi , Zhang Lihao , Chen Yaobing , Zhang Shu , Diao Xincai , Liu Yang , Shi Yishi , Wei Zhiyi , Chang Guoqing
Published: January 2024

We demonstrate a pre-chirp and gain jointly managed Yb-fiber laser that drives simultaneous label-free autofluorescence-multiharmonic (SLAM) medical imaging. We show that a gain managed Yb-fiber amplifier produces high-quality compressed pulses when the seeding pulses exhibit proper negative pre-chirp. The resulting laser source can generate 43-MHz, 34-fs pulses centered at 1110 nm with more than 90-nJ energy. We apply this ultrafast source to SLAM imaging of cellular and extracellular components in various human tissues of intestinal adenocarcinoma, lung adenocarcinoma, and liver.
Quantum analysis of a Mach–Zehnder interferometer with propagating a single photon Gaussian wave packet
Authors: Singh Siddharth , Katti Rohan
Published: January 2024

In this paper, a Mach–Zehnder interferometer is analyzed with a single photon Gaussian wave packet at one of its input ports and vacuum state at the other input port. Various noises arising in the Mach–Zehnder interferometer such as photon flux noise and quadrature noise are mathematically analyzed. The effect of variation in device parameters on the power spectral density at the output ports of the Mach–Zehnder interferometer is studied. It is observed that the power spectral density of photon flux noise autocorrelation at the output ports of a Mach–Zehnder interferometer is a function of phase shift, whereas the power spectral density of quadrature noise autocorrelation at the output ports of a Mach–Zehnder interferometer is a function of frequency of a single photon wave packet and the phase shift. The analysis carried out in this paper will be helpful in understanding the quantum fluctuations in the design of quantum logic devices and circuits where the Mach–Zehnder interferometer is a core building block.
Wavelength-tunable ultrafast two arm fiber laser system for transient interferometric scattering microscopy on nanoscopic objects
Authors: Birkmeier Konrad , Hartschuh Achim
Published: January 2024

Ultrafast time-resolved microscopy of single nano-objects is particularly challenging because of minute sample volumes and correspondingly small signal levels together with the possibility of photobleaching. We present a compact pulsed two arm fiber laser-based system suited for highly sensitive transient interferometric scattering (TiSCAT) microscopy of nanomaterials. A continuously tunable probe arm is used for spectrally resolved detection of the transient sample response in the range between 810 and 960 nm upon pulsed excitation at 780 nm by the pump arm. Coupled to a scanning confocal microscope with high numerical aperture objective, the system provides spectral maps with sub-300 nm spatial and 300 fs temporal resolution. We tested the platform using monolayer MoSe2 and individual (6,4) single-walled carbon nanotubes as model samples. Confocal microscopy images recorded for an exfoliated monolayer MoSe2 reveal spatially varying excited state decay, highlighting the need for local probing. Spectrally resolved TiSCAT measurements on individual (6,4) single-walled carbon nanotubes show that the transient response is dominated by ground-state bleaching with picosecond recovery times. The obtained data illustrate the excellent noise properties and stability of the newly developed laser system, which allow for nearly shot-noise limited TiSCAT detection at the low probe fluences required for avoiding photodegradation of sensitive nanomaterials.
Design of anti-temperature interference liquid level sensor based on π-phase-shifted LPFG near phase-matched turning points
Authors: Du Jie , Gu Zhengtian , Ling Qiang , Yan Yuxuan , Wang Ying , Nie Wenjie
Published: January 2024

A new, to the best of our knowledge, type of liquid level sensor with π-phase-shifted long-period fiber grating operating near the phase-matched turning point is proposed. The sensor introduces a π-phase shift at the center of the grating, which can generate three attenuation peaks due to the mode interference effect in the transmission spectrum of the sensor operating near the phase-matched turning points. According to the different liquid level and temperature sensing characteristics of three attenuation peaks, simultaneous detection of liquid level and temperature can be realized through wavelength modulation and intensity modulation detection. In this paper, the structural parameters of this liquid level sensor, such as grating period and grating length, are designed optimally based on the fiber grating coupled mode theory, and the wavelength spacing of the attenuation peaks on both sides and the intensity of the center attenuation peak are analyzed in relation to the liquid level and temperature. The simulation results show that the liquid level sensitivity is 5.58 nm/mm and −1.316dB/mm for wavelength modulation and intensity modulation, respectively, for the liquid level variation range of 0 to 18 mm; and the temperature sensitivity of wavelength modulation and intensity modulation is −0.139nm/∘C and 0.171 dB/°C, respectively, over the temperature variation range of 20°C to 80°C. Therefore the simultaneous detection of liquid level and temperature can be realized by establishing a measurement inversion matrix. Compared with other liquid level sensors, this sensor is expected to be widely used in the field of liquid level sensing due to its simple structure, high liquid level sensitivity, large liquid level measurement range, and narrow monitoring peak bandwidth.
Characterization of the nonlinear THz focus for 2D THz spectroscopy
Authors: Lin Haw-Wei , Hsieh Pin-Hsun , Mead Griffin , Blake Geoffrey A.
Published: January 2024

We present a sensitive imaging method capable of the selective characterization of the nonlinear THz beam profile, providing a direct handle to optimize χ(3) light-matter interactions that are critical to two-dimensional (2D) THz spectroscopies. In particular, this method facilitates the development of experimentally challenging 2D THz spectroscopies with multiple THz emitters, which enables direct investigations of fast picosecond dynamics in liquids and solids that are challenging in single-emitter 2D THz spectroscopic setups.
Multiplexed imaging in live cells using pulsed interleaved excitation spectral FLIM
Authors: Nguyen Trung Duc , Chen Yuan-I , Nguyen Anh-Thu , Chen Limin H. , Yonas Siem , Litvinov Mitchell , He Yujie , Kuo Yu-An , Hong Soonwoo , Rylander H. Grady , Yeh Hsin-Chih
Published: January 2024

Multiplexed fluorescence detection has become increasingly important in the fields of biosensing and bioimaging. Although a variety of excitation/detection optical designs and fluorescence unmixing schemes have been proposed to allow for multiplexed imaging, rapid and reliable differentiation and quantification of multiple fluorescent species at each imaging pixel is still challenging. Here we present a pulsed interleaved excitation spectral fluorescence lifetime microscopic (PIE-sFLIM) system that can simultaneously image six fluorescent tags in live cells in a single hyperspectral snapshot. Using an alternating pulsed laser excitation scheme at two different wavelengths and a synchronized 16-channel time-resolved spectral detector, our PIE-sFLIM system can effectively excite multiple fluorophores and collect their emission over a broad spectrum for analysis. Combining our system with the advanced live-cell labeling techniques and the lifetime/spectral phasor analysis, our PIE-sFLIM approach can well unmix the fluorescence of six fluorophores acquired in a single measurement, thus improving the imaging speed in live-specimen investigation.
Dyakonov waves generation at uniaxial chiral-plasma interface
Authors: Umair M. , Ghaffar A. , Alkanhal Majeed A. S. , Khan Y. , Shahid M. U.
Published: January 2024

Numerical analysis of Dyakonov waves generation has been carried out at uniaxial chiral-plasma planar interface. The extended electromagnetic wave theory is utilized, and an impedance boundary conditions approach is employed to obtain characteristics equation. Effective mode index and attenuation under the different values of collisional frequency, plasma frequency and chirality in the THz frequency range for three cases for uniaxial chiral media are discussed. These results can be used in the field of photonics and integrated optics to fabricate nanophotonic devices in the THz frequency range.
Ultra-compact acousto-optic modulation using on-chip integrated Bragg gratings on lithium niobate-chalcogenide hybrid platform
Authors: Yang Zhiqiang , Liu Dong , Zeng Siqing , Yang Shuixian , Chen Qingming , Chen Zhenshi , Wan Lei , Li Yan
Published: January 2024

An ultra-compact and efficient acousto-optic modulator based on a thin-film lithium niobate-chalcogenide (ChG) hybrid platform was designed and realized. In this approach, π phase-shift Bragg grating has an ultra-short effective interaction length of only ∼ 300 µm and a compact footprint of 200 × 300 µm2. The strong microwave-acoustic coupling and superior photo-elastic property of the ChG allow us to achieve a half-wave voltage of Vπ = 1.08 V (4.07 V) for the π phase-shift Bragg grating (waveguide Bragg grating), corresponding to VπL = 0.03 V·cm (0.09 V·cm). This acousto-optic modulator exhibits a compact size, and low power consumption, and can be used for on-chip optical interconnects and microwave photonics.
Broadband nonlinear optical response and sub-picosecond carrier dynamics in graphene-SnSe2 van der Waals heterostructures
Authors: Li Genglin , Feng Yangyang , Li Lingqi , Du Wenhui , Liu Hongliang , Sun Xiaoli , Zhao Xingjuan , Ma Yandong , Jia Yuechen , Chen Feng
Published: January 2024

The van der Waals (vdWs) heterostructures, with vertical layer stacking structure of various two-dimensional (2D) materials, maintain the reliable photonic characteristics while compensating the shortcomings of the participating individual components. In this work, we combine the less-studied multilayer tin selenide (SnSe2) thin film with one of the traditional 2D materials, graphene, to fabricate the graphene-based vdWs optical switching element (Gr-SnSe2) with superior broadband nonlinear optical response. The transient absorption spectroscopy (TAS) measurement results verify that graphene acts as the recombination channel for the photogenerated carrier in the Gr-SnSe2 sample, and the fast recovery time can be reduced to hundreds of femtoseconds which is beneficial for the optical modulation process. The optical switching properties are characterized by the I-scan measurements, exhibiting a saturable energy intensity of 2.82 mJ·cm-2 (0.425 µJ·cm-2) and a modulation depth of 15.6% (22.5%) at the wavelength of 1030 nm (1980nm). Through integrating Gr-SnSe2 with a cladding waveguide, high-performance picosecond Q-switched operation in the near-infrared (NIR) and mid-infrared (MIR) spectral regions are both achieved. This work experimentally demonstrates the great potential of graphene-based vdWs heterostructures for applications in broadband ultrafast photonics.
25 Gb/s NRZ transmission at 85°C using a high-speed 940 nm AlGaAs oxide-confined VCSEL grown on a Ge substrate
Authors: Yang Yun-Cheng , Wan Zeyu , Hsu Guei-Ting , Chiu Chih-Chuan , Chen Wei-Hsin , Feifel Markus , Lackner David , Xia Guangrui(Maggie) , Wu Chao-Hsin
Published: January 2024

In this Letter, we present a comprehensive analysis of the high-speed performance of 940 nm oxide-confined AlGaAs vertical-cavity surface-emitting lasers (VCSELs) grown on Ge substrates. Our demonstration reveals a pronounced superiority of Ge-based VCSELs in terms of thermal stability. The presented Ge-VCSEL has a maximum modulation bandwidth of 16.1 GHz and successfully realizes a 25 Gb/s NRZ transmission at 85 ∘C. The experimental results underscore the significance and potential of Ge-VCSELs for applications requiring robust performance in high-temperature environments, laying the cornerstone for the future development of VCSEL devices.
Needle of longitudinally polarized light using the circular Airy beam
Authors: An Zhe , Lu Wanli
Published: January 2024

An optical needle is created using a radially polarized circular Airy beam with a conical angle, stemmed from the auto-focusing property of light beams. The utilization of the angular spectrum representation serves to illustrate the field distributions of the optical needle, and an explicit formula is provided to describe the angular spectrum of the light beam. The findings suggest that the optical needle exhibits a long depth of focus and well uniformity, and the full width at half maximum of the transverse field distribution is approximately 0.38 λ beyond the diffraction limit. The uniformity of the optical needle can be tailored by adjusting the width of the primary ring, the decay parameter, and the conical angle. Additionally, the depth of focus of the optical needle significantly improves as the radius of the primary ring increases while still maintaining well uniformity. It may find applications in high-resolution optical imaging and optical manipulation.
High-purity and wide-angle reflective structural colors based on an all-dielectric Fabry–Pérot cavity structure
Authors: Yang Zhengmei , Li Wenfeng , Duan Huigao
Published: January 2024

High-purity structural colors with low fabrication cost are in demand for their commercial applications. Here, we demonstrate an all-dielectric Fabry–Pérot cavity structure consisting of four-layer lossy and lossless dielectric films alternately stacked for producing high-purity and angle-invariant reflective colors. Multiple cavity resonances function together to significantly suppress the undesired reflection with the enhanced optical absorption, leading to a distinct and saturated color with a high efficiency of ∼70%. Besides, due to the high refractive indices of constituent materials, the color appearance of the designed structure can be maintained well at ±50° incident angle for two polarization states. The excellent color performance of the proposed device together with cost-effective manufacturing convenience opens up new avenues for their large-area applications in various areas.
Low-threshold AlGaN-based deep ultraviolet laser enabled by a nanoporous cladding layer
Authors: Zhao Yongming , Deng Liqiong , Wu Feng , Zheng Zhihua , Jian Pengcheng , Liu Weijie , Chen Zhenyu , Tan Shizhou , Peng Meng , Guo Wei , Chen Changqing , Dai Jiangnan
Published: January 2024

We demonstrated an AlGaN-based multiple-quantum-well (MQW) deep ultraviolet (DUV) laser at 278 nm using a nanoporous (NP) n-AlGaN as the bottom cladding layer grown on the sapphire substrate. The laser has a very-low-threshold optically pumped power density of 79 kW/cm2 at room temperature and a transverse electric (TE)-polarization-dominant emission. The high optical confinement factor of 9.12% benefiting from the low refractive index of the nanoporous n-AlGaN is the key to enable a low-threshold lasing. The I–V electrical measurement demonstrates that an ohmic contact can be still achieved in the NP n-AlGaN with a larger but acceptable resistance, which indicates it is compatible with electrically driven laser devices. Our work provides insights into the design and fabrication of low-threshold lasers emitting in the DUV regime.
Polarization change of femtosecond laser pulses in air measured by electric-field-induced second-harmonic generation
Authors: Nakamura Shin , Fujii Takashi , Sato Masahiro , Kumada Akiko , Oishi Yuji
Published: January 2024

We experimentally demonstrated the polarization change of femtosecond laser pulses in air by using electric-field-induced second-harmonic generation (E-FISHG) for the first time to our knowledge. The polarization change from linear to elliptical was observed at the laser intensity over the filamentation threshold. These results suggest that the polarization change can occur by the birefringence caused by filamentation. This phenomenon can be used for new applications such as an ultra-fast and precise three-dimensional electric field measurement by E-FISHG. In addition, E-FISHG can be an excellent tool to investigate the characteristics of femtosecond laser propagation such as filamentation.
Global-optimal semi-supervised learning for single-pixel image-free sensing
Authors: Zhan Xinrui , Lu Hui , Yan Rong , Bian Liheng
Published: January 2024

Single-pixel sensing offers low-cost detection and reliable perception, and the image-free sensing technique enhances its efficiency by extracting high-level features directly from compressed measurements. However, the conventional methods have great limitations in practical applications, due to their high dependence on large labelled data sources and incapability to do complex tasks. In this Letter, we report an image-free semi-supervised sensing framework based on GAN and achieve an end-to-end global optimization on the part-labelled datasets. Simulation on the MNIST realizes 94.91% sensing accuracy at 0.1 sampling ratio, with merely 0.3% of the dataset holding its classification label. When comparing to the conventional single-pixel sensing methods, the reported technique not only contributes to a high-robust result in both conventional (98.49% vs. 97.36%) and resource-constrained situations (94.91% vs. 83.83%) but also offers a more practical and powerful detection fashion for single-pixel sensing, with much less human effort and computation resources.
Lensless imaging in one shot using the complex degree of coherence obtained by multiaperture interferences
Authors: Pedrini Giancarlo , Li Rujia , Cao Liangcai , Reichelt Stephan
Published: January 2024

The van Cittert–Zernike theorem states that the Fourier transform of the intensity distribution function of a distant, incoherent source is equal to the complex degree of coherence. In this Letter, we present a method for measuring the complex degree of coherence in one shot by recording the interference patterns produced by multiple aperture pairs. The intensity of the sample is obtained by Fourier transforming the complex degree of coherence. The experimental verification by using a simple object is presented together with a discussion on how the method could be improved for imaging more complex samples.
Bragg scattering of stochastic beams in PT-symmetric photonic lattices
Authors: Brandão P. A. , Cirino M. J. , Cavalcanti S. B.
Published: January 2024

The propagation of a Gaussian–Schell beam through a PT-symmetric optical lattice, whose index of refraction is represented by a sinusoidal type of function, is theoretically investigated. Within the framework of standard coherence theory, one is able to access and elucidate unexpected consequences of the interplay between the spatial coherence properties of the beam and the non-Hermitian nature of the photonic lattice. We describe how one may use a non-Hermitian periodic medium to enhance the spatial coherence properties of a partially coherent beam.
In situ surface turbidity sensor based on localized light scattering from tilted fiber Bragg gratings
Authors: Han Xile , Liu Weiru , Zu Lijiao , Wu Wen , Xie Jiwei , You Daotong , Du Minghui , Guo Tuan
Published: January 2024

We propose a compact fiber-optic sensor for in situ and continuous turbidity monitoring, based on surface optical scattering of polarized evanescent waves from targeted particles. The sensor is composed of a tilted fiber Bragg grating (TFBG) packaged inside a microfluidic capillary. The transmission spectrum of the TFBG provides a fine comb of narrow cladding resonances that are highly sensitive to the turbidity due to the localized light scattering of polarized evanescent waves from the microparticles near the fiber surface (as opposed to traditional bulk/volumetric turbidity measurement). We also propose a transmission spectral area interrogation method and quantify the repeatable correlation between the surface turbidity and the optical spectral area response. We show that the maximum sensitive turbidity response is achieved when the wavelength of the sensing cladding resonance matches the size of surrounding solid particles.
Resolved Raman sideband cooling of a single optically trapped cesium atom
Authors: Tian Zhuangzhuang , Chang Haobo , Lv Xin , Yang Mengna , Wang Zhihui , Yang Pengfei , Zhang Pengfei , Li Gang , Zhang Tiancai
Published: January 2024

We developed a resolved Raman sideband cooling scheme that can efficiently prepare a single optically trapped cesium (Cs) atom in its motional ground states. A two-photon Raman process between two outermost Zeeman sublevels in a single hyperfine state is applied to reduce the phonon number. Our scheme is less sensitive to the variation in the magnetic field than the commonly used scheme where the two outermost Zeeman sublevels belonging to the two separate ground hyperfine states are taken. Fast optical pumping with less spontaneous emission guarantees the efficiency of the cooling process. After cooling for 50 ms, 82% of the Cs atoms populate their three-dimensional ground states. Our scheme improves the long-term stability of Raman sideband cooling in the presence of magnetic field drift and is thus suitable for cooling other trapped atoms or ions with abundant magnetic sublevels.