Efficacy and safety of teriparatide vs. bisphosphonates and denosumab vs. bisphosphonates in osteoporosis not previously treated with bisphosphonates: a systematic review and meta-analysis of randomized controlled trials.

The study found that in osteoporosis patients who had not previously received bisphosphonate treatment and were in a treatment cycle of over 12 months, both teriparatide and denosumab significantly increased bone mineral density compared to bisphosphonates. Additionally, teriparatide was also shown to significantly decrease the risk of fractures. OBJECTIVE: The systematic review and meta-analysis aimed to assess and compare the safety and efficacy of teriparatide vs. bisphosphonates and denosumab vs. bisphosphonates in patients with osteoporosis who had not previously received bisphosphonates. METHODS: We conducted a search of published literature from inception to May 31, 2023, including databases such as PubMed, Embase, Cochrane Library, CNKI, SinoMed, VIP, and WanFang. The study only included head-to-head randomized controlled trials (RCTs) that compared teriparatide and denosumab with bisphosphonates to treat patients with osteoporosis. Fixed-effect model and random-effect model were used due to clinical heterogeneity. Meta-analysis was performed via Stata 17.0. RESULTS: A total of 6680 patients were enrolled across 23 eligible trials. The results of the meta-analysis showed that teriparatide was superior to bisphosphonates in decreasing the risk of fracture (risk ratio (RR) = 0.61, 95% confidence interval (CI) (0.51, 0.74), P < 0.001). Denosumab showed no benefit compared to bisphosphonates in reducing the risk of fracture in treating osteoporosis (RR 0.99, 95% CI (0.62, 1.57), P = 0.96). Compared with bisphosphonates, teriparatide and denosumab could significantly improve femoral neck, total hip, and lumbar spine bone mineral density (BMD) (P < 0.05). Furthermore, teriparatide and denosumab did not increase the incidence of adverse events (teriparatide vs. bisphosphonates, RR 0.92, 95% CI (0.79, 1.08), P = 0.32; denosumab vs. bisphosphonates, RR 0.98, 95% CI (0.95, 1.02), P = 0.37). CONCLUSIONS: Teriparatide is superior to bisphosphonates in decreasing the risk of fracture in patients with osteoporosis. In addition, teriparatide and denosumab were more efficacious than bisphosphonates in increasing the percentage change in BMD at the femoral neck, total hip, and lumbar spine.

Freeform imaging system with resolution that varies with the field angle in two dimensions.

The human eye's resolution varies with the field angle and has high center resolution and low edge resolution characteristics. In this paper, a freeform imaging system is presented that has resolution distribution characteristics similar to those of the human eye. Field-dependent parameters are used to describe the system's optical properties and a direct design method is proposed to realize the novel functionality. An off-axis reflective freeform imaging system with high center resolution and low edge resolution within a square 30°×30° field of view (FOV) is designed using this method. The maximum instantaneous field of view (IFOV) ratio of center field resolution to edge field resolution is 0.47. Only three freeform surfaces are used to attain good image quality. Simultaneous improvements are observed in both resolution and FOV while the detector remains fixed.

Design of a freeform imaging spectrometer based on a solution-diversified automatic design method.

A freeform imaging spectrometer design method is proposed. Only system specifications, including the slit length, numerical aperture, magnification, spectral range, and spectral resolution, are required as design inputs, and imaging spectrometer systems with various optical power distributions and structures are output. Using three-mirror imaging spectrometers as design examples, a series of initial solutions are obtained with a diffraction grating placed at the secondary mirror. In order to understand and explore the utilization of large number of output results, these initial solutions are visualized by mapping from high-dimensional solution space to three-dimensional space using the t-distributed symmetric neighbor embedding (t-SNE) dimensionality reduction algorithm; then a neural network is trained to fit the imaging qualities, showing good generalization performance, and can predict imaging quality for systems with unknown optical power distributions and structures.

Imaging spectrometer with single component of freeform concave grating.

In this Letter, an imaging spectrometer in which a freeform concave grating is the only optical component in the system is introduced. The degrees of freedom of optical freeform surfaces and a variable line-spacing (VLS) grating are used to realize imaging spectrometers. A point-by-point system design method is proposed that can generate a good initial solution rapidly. By exploring the limitations of the system specifications, it is demonstrated that the spectral dispersion, spectral resolving power, and system length can be improved significantly by using the freeform VLS concave grating. It is also found that freeform surfaces with higher degrees of freedom than a toroid can further improve system performance when using a VLS grating.

Simultaneous improvement of field-of-view and resolution in an imaging optical system.

A novel imaging system design is proposed, in which the FOV and maximum resolution are improved simultaneously while the detector remains fixed. These improvements are realized using freeform optical surfaces and field-dependent characteristic parameters. The resulting imaging system design has optical properties that vary continuously with the field angle. In the central FOV, the system is equivalent to a long-focal-length camera, while in the marginal FOV, it is equivalent to a short-focal-length camera; however, the system has a constant F-number across the FOV. A 2× variation in the field-dependent characteristic parameters across the FOV is achieved.

Towards automatic freeform optics design: coarse and fine search of the three-mirror solution space.

Design of an optical system, whether classic or novel, in the past or the present, requires significant effort from the designer. In addition to design methods and theories, the designer's skills and experience in optical system design are particularly important, which may require years of practice to learn. The diversity and variety of results are limited because of the difficulty, time, and labor costs required. In this article, we propose an automatic design method for freeform optics that can achieve a diverse range of three-mirror designs. The optical specifications and the design constraints are the only inputs required, and a variety of results can be obtained automatically. The output results have various structures and various optical power distributions with high imaging qualities. By implementing the design method, designers can not only realize an overview of the solution space of the three-mirror freeform system, but can also focus on specific designs.

Design of an oblique camera based on a field-dependent parameter.

In this paper, a new parameter, field focal length (FFL), is introduced to characterize the optical properties for each field of an optical system. A freeform three-mirror off-axis reflective system, working as an oblique camera, is found to have various FFLs across the field angle of 30°. With the help of FFL, the ground resolution (GR) of this camera is analyzed under two working modes. One of the two working modes has more uniform GR when the field with larger FFL value aims at the object far away from the camera. By using FFL to control the GR, an oblique camera system is designed that has a constant GR within 99.41% over the field of view.

Design method for freeform optical systems containing diffraction gratings.

A design method for freeform optical systems containing diffraction gratings is developed based on Fermat's principle and Ludwig's grating ray-tracing equation. The proposed method can calculate fine starting-points for diffraction-grating-based imaging spectrometers with high performance and novel geometries. It can also be extended to design optical systems that contain other dispersive elements, such as prisms and diffractive optics. Two freeform imaging spectrometers are designed by this method to meet the diffraction-limited specifications.

Multiple surface expansion method for design of freeform imaging systems.

The relative aperture size and the field-of-view (FOV) are two significant parameters for optical imaging systems. However, it is difficult to improve relative aperture size and FOV simultaneously. In this paper, a freeform design method is proposed that is particularly effective for high performance systems. In this step-by-step method, the FOV is enlarged from a small initial value in equal-length steps until it reaches the full FOV; in each step, part of the area of one system surface is constructed. A freeform off-axis three-mirror imaging system with large relative aperture size and a wide FOV is designed as an example. The system operates at F/2.5 with 150 mm effective focal length and a 60° × 1° FOV. The average root-mean-square wavefront error of the system is 0.089λ (working wavelength λ = 530.5 nm).