Differences in Vertebral Morphology and bone Mineral Density between Grade 1 Vertebral Fracture and Non-Fractured Participants in the Chinese Population.

PURPOSE: To investigate the difference in vertebral morphology and bone mineral density (BMD) between grade 1 VFs and non-fractured participants in the Chinese population to shed light on the clinical significance of grade 1 VFs from various perspectives. METHODS: This retrospective cohort study included patients who received a chest low-dose computed tomography (LDCT) scan for health examination and visited the First Affiliated Hospital of Zhengzhou University, Henan, China, from October 2019 to August 2022. Data were analyzed from March 2023 to July 2023. The main outcome of this study was the difference in morphological parameters and BMD between grade 1 VFs and non-fractured participants. The prevalence of grade 1 VFs in China populations was calculated. The difference in BMD of three fracture types in the Grade 1 group was also evaluated. RESULTS: A total of 3652 participants (1799 males, 54.85 ± 9.02 years, range, 40-92 years; 1853 females, 56.00 ± 9.08 years, range, 40-93 years) were included. The prevalence of grade 2 and 3 increase with age. The prevalence of grade 1 VFs gradually increases ≤ 50y to 60-69y group, but there is a decrease in the ≥ 70 years male group (6.6%) and a rise in the female group (25.5%). There was no significant statistical difference observed in vertebral shape indices (VSI) and BMD between the Grade 1 group and the no-fractured group aged < 50 years old except the wedge index in male. The biconcavity index did not differ between the non-fractured group and the Grade 1 group in men aged 50-59 years, whereas a significant statistical difference was observed in women. Additionally, the results of BMD were consistent with these findings. For the 40-59 years age group, there were significant differences between the compression deformity group and the other groups. CONCLUSIONS: The grade 1 group had higher VSI and lower BMD than the non-fractured group, suggesting an association between the Grade 1 group and osteoporosis in individuals aged over 50 for women and over 60 for men. Different fracture types have significant variations in BMD among middle-aged people. The prevalence of grade 1 VFs exhibits an age-related increase in both genders, with opposite trends observed between older males and females. We suggested VSI can aid physicians in the diagnosis of grade 1 VFs.

Self-focusing and self-splitting properties of partially coherent temporal pulses propagating in dispersive media.

Based on the coherence theory for non-stationary optical fields, we introduce a new class of partially coherent pulse sources with multi-cosine-Gaussian correlated Schell-model (MCGCSM) and derive the analytic expression for the temporally mutual coherence function (TMCF) of an MCGCSM pulse beam when it propagates through dispersive media. The temporally average intensity (TAI) and the temporal degree of coherence (TDOC) of the MCGCSM pulse beams spreading in dispersive media are investigated numerically, respectively. Our results show that over propagation distance, the evolution of pulse beams is from the primary single beam into multiple subpulses or form flat-topped TAI distributions by controlling source parameters. Moreover, when the chirp coefficient s < 0, the MCGCSM pulse beams through dispersive media will show the characteristics of two self-focusing processes. The reason why there are two self-focusing processes is explained from the perspective of physical meaning. The results in this paper can open the applications of pulse beams in multiple pulse shaping and laser micromachining and material processing.

Dissipative Particle Dynamics Simulation of the Sensitive Anchoring Behavior of Smectic Liquid Crystals at Aqueous Phase.

Rational design of thermotropic liquid crystal (LC)-based sensors utilizing different mesophases holds great promise to open up novel detection modalities for various chemical and biological applications. In this context, we present a dissipative particle dynamics study to explore the unique anchoring behavior of nematic and smectic LCs at amphiphile-laden aqueous-LC interface. By increasing the surface coverage of amphiphiles, two distinct anchoring sequences, a continuous planar-tilted-homeotropic transition and a discontinuous planar-to-homeotropic transition, can be observed for the nematic and smectic LCs, respectively. More importantly, the latter occurs at a much lower surface coverage of amphiphiles, demonstrating an outstanding sensitivity for the smectic-based sensors. The dynamics of reorientation further reveals that the formation of homeotropic smectic anchoring is mainly governed by the synchronous growth of smectic layers through the LCs, which is significantly different from the mechanism of interface-to-bulk ordering propagation in nematic anchoring. Furthermore, the smectic LCs have also been proven to possess a potential selectivity in response to a subtle change in the chain rigidity of amphiphiles. These simulation findings are promising and would be valuable for the development of novel smectic-based sensors.

[Birth weight curves of singleton neonates with a gestational age of 24-42 weeks and their regional differences in 11 cities of China: an analysis of 93 720 cases]. / 中国11市93 720例胎龄24~42å‘¨å•èƒŽå„¿å‡ºç”Ÿä½“é‡æ›²çº¿åŠå ¶åœ°åŒºå·®å¼‚ç‰¹å¾.

OBJECTIVES: To develop the birth weight curve of singleton neonates with a gestational age of 24-42 weeks, and to investigate the regional differences of the birth weight curve. METHODS: A total of 11 maternal and child health hospitals with more than 7 000 neonates delivered annually were selected in 11 cities of China (Haikou, Guangzhou, Shenzhen, Liuzhou, Guilin, Quanzhou, Chongqing, Chengdu, Changsha, Ningbo, and Lianyungang), and all live singleton neonates delivered in the 11 hospitals from January 1, 2017 to December 31, 2020 were enrolled for the development of birth weight curves. RESULTS: A total of 93 720 singleton neonates with a gestational age of 24-42 weeks from the 11 cities were included in the study. The reference values of the 3rd-97th percentiles of birth weight of singleton neonates for the total of the 11 cities and for each of the 11 cities were established, and the birth weight percentile curves were drawn. The birth weight curve level of singleton neonates in Shenzhen and Quanzhou was almost the same as the average level of the 11 cities; the birth weight curve level of singleton neonates in Haikou, Guangzhou, Guilin, and Liuzhou was slightly lower than the average level of the 11 cities; the birth weight curve level of singleton neonates in Chongqing, Chengdu, and Changsha was slightly higher than the average level of the 11 cities; the birth weight curve level of singleton neonates in Ningbo and Lianyungang was higher than the average level of the 11 cities. The average birth weight curve level of singleton neonates in the 11 cities were very close to that of China Neonatal Cooperation Network in 2011-2014. CONCLUSIONS: The reference values of the 3rd-97th percentiles of birth weight of singleton neonates for the total of the 11 cities and for each of the 11 cities are developed, which can be used as a reference for evaluating the intrauterine growth of singleton neonates in the region. The level of intrauterine growth of neonates in some cities is different from the national level.

[Birth weights of singleton neonates of 14 Chinese ethnic groups in 11 cities of China]. / 中国11市14ä¸ªæ°‘æ—å•èƒŽå„¿å‡ºç”Ÿä½“é‡ç ”ç©¶.

OBJECTIVES: To develop the birth weight curves of the Chinese Han (26-41 weeks of gestation) and Zhuang (28-41 weeks of gestation) singleton neonates in 11 cities of China, as well as the birth weight means of full-term neonates of 14 Chinese ethnic groups. METHODS: The live singleton neonates who were born in 11 maternal and child health care hospitals from 11 cities of China between January 2017 and December 2020 were classified according to the mother's ethnic group. Birth weight means were calculated for the full-term neonates of each ethnic group. For the Han and Zhuang singleton neonates with a large sample size, the Lambda-Mu-Sigma (LMS) method was used to establish the birth weight percentile curves of the Han and Zhuang singleton neonates with different gestational ages. RESULTS: A total of 105 365 live singleton neonates were included, among whom the Han neonates had the highest number of 84 851 (26-41 weeks of gestation), followed by the Zhuang neonates (12 803 neonates with a gestational age of 28-41 weeks). The neonates of the other Chinese ethnic groups enrolled were live full-term singleton neonates, with a sample size of more than 100 neonates for each ethnic group. The 3rd-97th percentile curves of birth weight were established for the Han singleton neonates with a gestational age of 26-41 weeks and the Zhuang singleton neonates with a gestational age of 28-41 weeks. The birth weight curves of the Han singleton neonates at each gestational age were higher than those of the Zhuang singleton neonates. Birth weight means (3 199-3 499 g) and standard deviations were determined for 14 Chinese ethnic groups, i.e., Li, Mulao, Zhuang, Yao, Dong, Miao, Han, Buyi, Mongolian, Tujia, Yi, Hui, Man, and Korean ethnic groups. The Li ethnic group had the lowest birth weight, followed by the Mulao, Zhuang, Yao, Dong, Miao, Han, Buyi, Mongolian, Tujia, Yi, Hui, Man, and Korean ethnic groups. CONCLUSIONS: The 3rd-97th percentile curves of birth weight are developed for the Han (26-41 weeks of gestation) and Zhuang (28-41 weeks of gestation) singleton neonates in 11 cities of China, and birth weight means are determined for the full-term neonates of 14 Chinese ethnic groups in 11 cities of China, which provides a reference for evaluating the intrauterine growth of neonates in these ethnic groups.

Birth weight curves of twin neonates with a gestational age of 25-40 weeks and their regional differences in 11 cities of China: an analysis of 17 256 cases. / 中国11市17 256例胎龄25~40周双胎儿出生体重曲线及地区差异特征.

OBJECTIVES: To develop the birth weight curve of twin neonates with a gestational age of 25-40 weeks, and to investigate the regional differences of the birth weight curve. METHODS: A total of 11 maternal and child health care hospitals with more than 7 000 neonates delivered annually were selected in 11 cities of China (Haikou, Guangzhou, Liuzhou, Guilin, Quanzhou, Shenzhen, Chongqing, Chengdu, Changsha, Ningbo, and Lianyungang), and all live twin neonates delivered in the 11 hospitals from January 1, 2017 to December 31, 2020 were enrolled for the development of birth weight curves. RESULTS: A total of 17 256 twin neonates with a gestational age of 25-40 weeks from the 11 cities were included in the study. The reference values of the 3rd-97th percentiles of birth weight of twin neonates for the total of the 11 cities and for each of the 11 cities in China were established, and the birth weight percentile curves were drawn. The birth weight curve level of twin neonates in Liuzhou was lower than the average level of the 11 cities; the birth weight curve level of twin neonates in Ningbo was higher than the average level of the 11 cities; the birth weight curve level of twin neonates in Lianyungang was obviously higher than the average level of the 11 cities; the birth weight curve level of twin neonates in other 8 cities was almost the same as the average level of the 11 cities. CONCLUSIONS: The reference values of the 3rd-97th percentiles of birth weight of twin neonates for the total of the 11 cities and for each of the 11 cities are developed, which can be used as a reference for evaluating the intrauterine growth of twin neonates in the region. The level of intrauterine growth of twin neonates in some cities is different from the average level of the 11 cities of China.

Propagation of orbital angular momentum modes carried by hollow vortex Gaussian beams in anisotropic atmospheric turbulence.

We establish the propagation model of orbital angular momentum (OAM) modes carried by hollow vortex Gaussian (hvG) beams propagating in anisotropic atmospheric turbulence. Effects of light source parameters and atmospheric conditions on the OAM mode propagation performance are investigated in detail. The findings indicate the hvG beam with a smaller OAM quantum number, a larger beam order, or a longer source wavelength has more robust resistance to atmospheric turbulence interference. The waist width of the light source has different influences on the OAM mode propagation at different propagation distances. Atmospheric turbulences with larger values of anisotropy, inner-scale factor, non-Kolmogorov power spectrum index, and altitude are favorable for the OAM mode propagation. These research results are conducive to optimizing the design of light sources and space wireless communication systems with hvG beams.

Propagation characteristics of the perfect vortex beam in anisotropic oceanic turbulence.

The propagation model of orbital angular momentum (OAM) modes carried by the perfect vortex (pv) beam through anisotropic oceanic turbulence links is established and the factors influencing the OAM propagation are discussed. The findings show that the self-focusing property of pv beams is beneficial to the propagation of OAM modes: a smaller topological charge, a smaller initial radius, and an optimized half-ring width can alleviate degrading effects of turbulence on the pv beam. Additionally, the pv beam with a longer wavelength is more resistant to turbulent interference. The oceanic conditions with a higher dissipation rate of kinetic energy per unit mass of seawater, larger values of anisotropy and inner-scale factor, a smaller temperature-salinity contribution ratio, or a lower mean-squared temperature dissipation rate can improve the signal mode detection probability. The results are expected to further optimize the design of OAM-based underwater wireless communication systems.

Pure-three-level Yb:GdCOB CW laser at 976 nm.

We present what is, to the best of our knowledge, the first pure-three-level Yb:Ca4GdO(BO3)3 (Yb:GdCOB) laser emitting at 976 nm based on the F5/22-F27/2 transition, generally used for a quasi-three-level emission at 1032 nm. A maximum power of 782 mW at 976 nm has been achieved in continuous-wave (CW) operation pumped by a quasi-three-level Nd:SrLaAlO4 laser emitting at 902 nm. Moreover, a self-frequency-doubling CW blue laser has also been demonstrated with a maximum power of 133 mW at 488 nm.

[Differences in intrauterine growth levels between full-term neonates born to primiparous or multiparous women].

OBJECTIVE: To establish the intrauterine growth percentile curves of full-term neonates with different gestational ages (GAs) born to primiparous or multiparous women, and to investigate the influence of parity on intrauterine growth potential. METHODS: Cross-sectional cluster sampling was performed from April 2013 to September 2015 to measure physical growth in full-term singleton infants with a GA of 37-41 weeks in two hospitals in Shenzhen, China. The Lambda-Mu-Sigma method was used for curve fitting. RESULTS: The mean values of birth weight, body length, head circumference, chest circumference, and crown-rump length were obtained in 14 529 full-term infants. The 10th, 25th, 50th, 75th, and 90th percentile curves of the five indices were established. The full-term infants born to multiparous women had similar patterns and growth trends of the five percentile curves of the above five indices to those born to primiparous women, while the full-term infants with a GA of 37-41 weeks born to multiparous women had higher mean values and percentile curve values of the above five indices than those born to primiparous women. In the group with a GA of 41 weeks, there was no significant difference in the crown-rump length between the infants born to primiparous women and those born to multiparous women, but there were significant differences in the means of the above five indices in all the other GA groups between the two group infants (P<0.05). CONCLUSIONS: Full-term infants with a GA of 37-41 weeks born to multiparous women have higher intrauterine growth levels of birth weight, body length, head circumference, chest circumference, and crown-rump length than those born to primiparous women, suggesting that parity is an important influencing factor for intrauterine growth potential.

[A study of Ververck index in 16 865 singleton neonates with a gestational age of 27-42 weeks in Shenzhen, China].

OBJECTIVE: Ververck index (VI) reflects thoracic development, body type, and nutritional status. This study aimed to investigate the VI of singleton neonates with a gestational age (GA) of 27-42 weeks at birth, and to establish percentile curves of VI of the neonates. METHODS: Cross-sectional cluster sampling was performed between April 2013 and September 2015. Body weight, body length, and chest circumference were measured for 16 865 singleton neonates with a GA of 27-42 weeks in two hospitals in Shenzhen, China. VI was calculated and the percentile curves of VI were plotted for the neonates. RESULTS: Mean VIs were obtained for singleton neonates with a gestational age of 27-42 weeks (in three groups of male, female, and both sexes), and related 3rd-97th percentile curves were plotted. As for the 50th percentile curve, the singleton neonates with a GA of 27 weeks had the lowest 50th percentile value of VI, which gradually increased with the increase in GA. The singleton neonates with a GA of 42 weeks had the highest 50th percentile value of VI. Girls had a slightly higher 50th percentile value of VI than boys in all GA groups. CONCLUSIONS: VI of neonates increases with the increase in GA. Female neonates may have a slightly better thoracic development, body type, and nutritional status than male neonates at birth. The percentile curves of VI plotted for singleton neonates with a GA of 27-42 weeks (in three groups of male, female, and both sexes) can provide a basis for evaluating thoracic development, body type, and nutritional status of neonates at birth in Shenzhen, China.

[Kaup index in 16 887 singleton neonates with a gestational age of 27-42 weeks in Shenzhen, China].

OBJECTIVE: To study the Kaup index (KI), an index used to evaluate body burliness and nutritional status, of neonates with a gestational age (GA) of 27-42 weeks at birth, and to establish the percentile curves of KI. METHODS: Cross-sectional cluster sampling was performed from April 2013 to September 2015 to select 16 887 singleton neonates with a GA of 27-42 weeks in two hospitals in Shenzhen, China. Body weight and body length were measured to calculate KI. The percentile curves of KI were plotted in these neonates. RESULTS: Mean KIs and corresponding standard deviations were obtained for singleton neonates with a gestational age of 27-42 weeks (in male, female, and mixed groups), and the 3rd-97th percentile curves of KI were plotted. The singleton neonates with a GA of 27 weeks had the lowest 50th percentile value of KI, and KI gradually increased with GA. Boys had a higher 50th percentile value of KI than girls in each GA group. In all groups except the 33-week GA group, boys had a higher mean KI than girls, and there was a significant difference in the mean KI between boys and girls in the GA groups of 34 and 36-40 weeks (P<0.05). CONCLUSIONS: KI of neonates at birth increases with GA, suggesting that body density and body burliness increase with GA. Boys have better body burliness than girls at birth. The percentile curves of KI plotted for singleton neonates with a GA of 27-42 weeks (in male, female, and mixed groups) can provide a reference for evaluating the body burliness and nutritional status of neonates at birth in Shenzhen.

[Intrauterine growth status of twin neonates with a gestational age of 27-40 weeks].

OBJECTIVE: To establish the intrauterine growth curve of twin neonates, and to investigate the intrauterine growth status of twin neonates. METHODS: Cross-sectional cluster sampling was performed for an on-the-spot investigation of 1 296 live twin neonates who were born in two hospitals in Shenzhen between April 2013 and September 2015. The Lambda-Mu-Sigma method was used for the curve fitting of body weight, body length, head circumference, chest circumference, and crown-rump length. RESULTS: The means and 3rd-97th percentile intrauterine growth curves for body weight, body length, head circumference, chest circumference, and crown-rump length were obtained for the 1 296 twin neonates with a gestational age of 27-40 weeks. The curve values of the 1 296 twin neonates for body weight, body length, head circumference, chest circumference, and crown-rump length were all lower than those of singleton neonates in Shenzhen that had been reported, and the difference increased with increasing gestational age. CONCLUSIONS: The intrauterine growth curves for body weight, body length, head circumference, chest circumference, and crown-rump length of twin neonates with a gestational age of 27-40 weeks in Shenzhen obtained in this study can provide a reference for evaluating the intrauterine growth status of twin neonates among the current population in Shenzhen.

Evolution properties of partially coherent standard and elegant Hermite-Gaussian beams in uniaxial crystals.

The propagation properties of a partially coherent elegant Hermite-Gaussian beam (EHGB) and a partially coherent standard Hermite-Gaussian beam (SHGB) in uniaxial crystals orthogonal to the optical axis are studied. The propagation expression for the cross-spectral density of the partially coherent EHGB and SHGB propagating in a uniaxial crystal is derived. With the help of the derived formula, some analyses are illustrated by numerical examples related to the evolution properties of the spectral density, the spectral degree of coherence, and the effective beam width of the partially coherent EHGB and SHGB in a uniaxial crystal. It is shown that propagation properties of the partially coherent EHGB and SHGB in an isotropic crystal are much different from the evolution properties in an anisotropic crystal. The evolution behavior of spectral density and the spectral degree of coherence depends on the parameters of the uniaxial crystals (the ratio of extraordinary and ordinary refractive indices), and beam parameters including the coherence length and the beam order, as well as the propagation distance.

[Intrauterine growth curves for body weight, body length, head circumference, chest circumference, and crown-rump length in 16 887 neonates with a gestational age of 27-42 weeks in Shenzhen, China].

OBJECTIVE: To establish the intrauterine growth curves of neonates in Shenzhen, China and to investigate the intrauterine growth of neonates in Shenzhen. METHODS: Cross-sectional cluster sampling was performed for an on-the-spot investigation of 16 887 neonates (9 418 males and 7 469 females) with a gestational age of 27-42 weeks who were born in two hospitals in Shenzhen from April 2013 to September 2015. The Lambda Mu Sigma (LMS) method was used for the curve fitting of body weight, body length, head circumference, chest circumference, and crown-rump length. RESULTS: The 3rd-97th percentile intrauterine growth curves for body weight, body length, head circumference, chest circumference, and crown-rump length were plotted for the neonates with a gestational age of 27-42 weeks who were divided into three groups (male, female, and mixed). The male neonates had significantly higher curves for the five indices than the female counterparts. The pattern and changing trend of body weight curves of these neonates were basically consistent with those in China Neonatal Network. CONCLUSIONS: The percentile intrauterine growth curves for body weight, body length, head circumference, chest circumference, and crown-rump length in neonates with a gestational age of 27-42 weeks in Shenzhen which has been established can provide a reference for clinical practice in the department of neonatology.

Radial phased-locked partially coherent flat-topped vortex beam array in non-Kolmogorov medium.

The analytical expressions for the cross-spectral density, the average intensity and the complex degree of spatial coherence of a radial phased-locked partially coherent flat-topped vortex beam array propagating through non-Kolmogorov medium are obtained by using the extended Huygens-Fresnel principle. The evolution behaviors of a radial phased-locked partially coherent flat-topped vortex beam array propagating through non-Kolmogorov medium are studied in detail. It is shown that the evolution behaviors of average intensity depend on beam parameters including the spatial correlation length, the radius of the beam array, as well as the propagation distance. A radial phased-locked partially coherent flat-topped vortex beam array with high coherence evolves more rapidly than that with low coherence.

[Study on height-weight indices in newborns of different gestational ages].

OBJECTIVE: To establish height-weight indices in newborns of different gestational ages and to provide reference data for evaluation of intrauterine fetal growth. METHODS: The weight, height, crown-rump length, head circumference, and chest circumference of 8 357 newborns were measured in Maternal and Child Health Care Hospital of Bao'an District of shenzhen between 2005 and 2006, with the method of fact-finding investigation with cross-sectional cluster sampling, to establish the height-weight indices in newborns of different gestational ages. RESULTS: Five gender-specific height-weight indices (Quetelet Index, QI; Kaup Index, KI; Rohrer Index, RI; Livi Index, LI; Polock Index, PI) in newborns of different gestational ages (28-44 weeks of gestation) in three different groups (boys+girls, boys, and girls) were established in Shenzhen, China, and were expressed as mean gestational weeks±SD. The five indices above all increased with increasing gestational age, and the highest values appeared at 41-43 gestational weeks, suggesting that body density and enrichment degree increased constantly with increasing gestational age. Three indices (QI, KI and PI) were higher in boys than in girls (P<0.05). CONCLUSIONS: With the increasing gestational age, the body density and enrichment degree of newborns increase, and the enrichment degree in boys is better than that in girls.

Orthogonally polarized dual-wavelength Nd:YAlO(3) laser at 1341 and 1339 nm and sum-frequency mixing for an emission at 670 nm.

We report a diode-pumped continuous wave (cw) orthogonally polarized dual-wavelength laser at 1339 and 1341 nm with a single b-cut Nd:YAlO(3) (Nd:YAP) crystal. By adjusting the tilt angle of the uncoated glass plate inserted in the laser cavity, we can control the cavity losses of two polarized directions. The output wavelengths are 1339 nm in a-axis polarization and 1341 nm in c-axis polarization, respectively, which are orthogonal to each other. At an incident pump power of 17.3 W, the cw output power obtained at 1339 and 1341 nm is 1.6 and 2.3 W, respectively. Furthermore, intracavity sum-frequency mixing at 1339 and 1341 nm was then realized in a KTiOPO(4) (KTP) crystal to reach the red range. To our knowledge, this is the first work realizing an orthogonally polarized dual-wavelength Nd:YAP laser based on the (4)F(3/2-)-(4)I(13/2) transition. Such a dual-wavelength laser would be especially valuable as a compact laser source to generate terahertz emission because the frequency difference between 1339 and 1341 nm is about 0.9 THz.

Dual-energy computed tomography and micro-computed tomography for assessing bone regeneration in a rabbit tibia model.

To gain a more meaningful understanding of bone regeneration, it is essential to select an appropriate assessment method. Micro-computed tomography (Micro-CT) is widely used for bone regeneration because it provides a substantially higher spatial resolution. Dual-energy computed tomography (DECT) ensure shorter scan time and lower radiation doses during quantitative evaluation. Therefore, in this study, DECT and Micro-CT were used to evaluate bone regeneration. We created 18 defects in the tibial plateau of the rabbits and filled them with porous polyetheretherketone implants to promote bone regeneration. At 4, 8, and 12 weeks, Micro-CT and DECT were used to assess the bone repair in the defect region. In comparison to Micro-CT (152 ± 54 mg/cm3), the calcium density values and hydroxyapatite density values obtained by DECT [DECT(Ca) and DECT(HAP)] consistently achieved lower values (59 ± 25 mg/cm3, 126 ± 53 mg/cm3). In addition, there was a good association between DECT and Micro-CT (R = 0.98; R2 = 0.96; DECT(Ca): y = 0.45x-8.31; DECT(HAP): y = 0.95x-17.60). This study highlights the need to use two different imaging methods, each with its advantages and disadvantages, to better understand the bone regeneration process.

Lightweight and drift-free magnetically actuated millirobots via asymmetric laser-induced graphene.

Millirobots must have low cost, efficient locomotion, and the ability to track target trajectories precisely if they are to be widely deployed. With current materials and fabrication methods, achieving all of these features in one millirobot remains difficult. We develop a series of graphene-based helical millirobots by introducing asymmetric light pattern distortion to a laser-induced polymer-to-graphene conversion process; this distortion resulted in the spontaneous twisting and peeling off of graphene sheets from the polymer substrate. The lightweight nature of graphene in combine with the laser-induced porous microstructure provides a millirobot scaffold with a low density and high surface hydrophobicity. Magnetically driven nickel-coated graphene-based helical millirobots with rapid locomotion, excellent trajectory tracking, and precise drug delivery ability were fabricated from the scaffold. Importantly, such high-performance millirobots are fabricated at a speed of 77 scaffolds per second, demonstrating their potential in high-throughput and large-scale production. By using drug delivery for gastric cancer treatment as an example, we demonstrate the advantages of the graphene-based helical millirobots in terms of their long-distance locomotion and drug transport in a physiological environment. This study demonstrates the potential of the graphene-based helical millirobots to meet performance, versatility, scalability, and cost-effectiveness requirements simultaneously.