[Evaluation of the relationship between the attachment type of lateral pterygoid muscle and the position of temporomandibular joint disc in patients with temporomandibular joint disorders based on wireless amplified MRI detector high resolution imaging].

Objective: To explore the correlation between the attachment type of lateral pterygoid muscle (LPM) and the position of temporomandibular joint (TMJ) disc in patients with temporomandibular disorders (TMD) by using wireless amplified magnetic resonance imaging detector (WAND) coupled with conventional head and neck joint coil for high resolution imaging of TMJ. Methods: Eighty-five patients with TMD diagnosed by oral and maxillofacial surgeons of Guizhou Provincial People's Hospital from October 2019 to January 2022 were collected. A total of 160 TMJ were included. There were 16 males and 69 females, aged (32.7±14.2) years. All patients were scanned with open, closed oblique sagittal and coronal WAND coupled head and neck coils with bilateral TMJ. Based on TMJ and LPM high resolution imaging, to explore the correlation between LPM attachment types and the position of TMJ disc in TMD patients, and to evaluate the potential clinical value of LPM attachment types in TMD patients. χ2 test and Pearson correlation analysis were used to evaluate the correlation between LPM attachment type and TMJ disc location. Results: There were three types of LPM attachment: type Ⅰ in 51 cases [31.9% (51/160)], type Ⅱ in 77 cases [48.1% (77/160)] and type Ⅲ in 32 cases [20.0% (32/160)]. There was a significant correlation between the type of LPM attachment and the position of articular disc (χ2=28.20, P=0.002, r=0.776). There was no statistical significance between the type of LPM attachment and the reversible displacement of articular disc (χ2=0.24, P=0.887, r=0.825). Conclusions: There is a correlation between the attachment type of LPM and the position of the disc in TMD patients. WNAD coupled with conventional head and neck joint coil TMJ high resolution scan can provide reliable imaging evidence for TMD patients in evaluating the type of LPM attachment and the location of disc.

Clinical application of cinematic rendering in maxillofacial fractures.

The purpose of this study was to evaluate the clinical application of cinematically rendered reconstructions of maxillofacial fractures. Ten surgeons and eight radiologists were shown three-dimensional images of 25 different patient cases, generated using both the volume rendering (VR) technique and the cinematic rendering (CR) technique. They were asked to mark the site of the fracture on the three-dimensional images and record the time this activity took. The effectiveness of the reconstructions to communicate with patients was assessed through the opinions of the surgeons and radiologists, as well as 25 patients. Subjective evaluations of the clinical value of the images were performed by the 18 surgeons and radiologists using a 10-item questionnaire. The percentages of correctly identified fractures of the nasal bone (P = 0.034), fracture dislocation (P < 0.001), and free bone fragments (P < 0.001) were significantly higher for CR images when compared to VR images, and identification took an average of 20.81 seconds for CR and 27.48 seconds for VR (P < 0.001). CR images were found to be more beneficial for communication with patients and scored higher for the display of fracture dislocation and free bone fragments than VR images (P < 0.05). CR images were found to have high clinical value in the visualization of maxillofacial fractures.

[Clinical characteristics of treadmill abrasion in children].

Objective: To analyze the clinical characteristics of treadmill abrasion in children. Methods: The medical records of 12 children with treadmill abrasion who were admitted to Tongren Hospital of Wuhan University & Wuhan Third Hospital (hereinafter referred to as the author's unit) from August 2017 to August 2019 were retrospectively analyzed. The data of gender, age, time of seeing a doctor after injury, injury environment and cause, abrasion site, abrasion area, abrasion depth, and wound treatment method and outcome of children were analyzed. Results: (1) The children included 5 males and 7 females, with the age of 2 to 6 years. Three children were treated on the same day after injury, and 9 children were treated 7 to 15 days after injury. (2) All the children were injured at home, and the abrasion was mainly caused by touching the running treadmill when their parents were using it. The contact area was mainly the gap between the rear track axle and the metal plate at the lower edge. (3) All the children had abrasion in the hands. The index finger, middle finger, and ring finger were the main involved fingers. The area of the abrasion was 2 cm×2 cm to 8 cm×5 cm, all of them were deep-partial thickness and above. (4) The children were mainly treated in outpatient department (9 children), and 10 children were conducted with conservative treatment. Eleven children had local scar formation, after anti-scar treatment and functional exercise, they recovered well without obvious dysfunction. Conclusions: Hands in those children are the most vulnerable part of treadmill abrasion injury, with the index finger, middle finger, and ring finger being frequently involved. The wound area is generally small, and most of the wounds are deep abrasion injuries.

Atmospheric Spectroscopy and Photochemistry at Environmental Water Interfaces.

The air-water interface is ubiquitous in nature, as manifested in the form of the surfaces of oceans, lakes, and atmospheric aerosols. The aerosol interface, in particular, can play a crucial role in atmospheric chemistry. The adsorption of atmospheric species onto and into aerosols modifies their concentrations and chemistries. Moreover, the aerosol phase allows otherwise unlikely solution-phase chemistry to occur in the atmosphere. The effect of the air-water interface on these processes is not entirely known. This review summarizes recent theoretical investigations of the interactions of atmosphere species with the air-water interface, including reactant adsorption, photochemistry, and the spectroscopy of reactants at the water surface, with an emphasis on understanding differences between interfacial chemistries and the chemistries in both bulk solution and the gas phase. The results discussed here enable an understanding of fundamental concepts that lead to potential air-water interface effects, providing a framework to understand the effects of water surfaces on our atmosphere.

Role of interleukin-4 genetic polymorphisms and environmental factors in the risk of asthma in children.

Asthma is an allergic disease characterized by hyperresponsiveness and chronic inflammation of the airway. The interleukin-4 (IL-4) gene and its single nucleotide polymorphisms are associated with asthma susceptibility in children. A case-control study was performed to evaluate the relationship between asthma risk and the IL-4 rs2243250 (589 C/T) and rs2070874 (107 T/C), and IL-4 receptor (IL-4R) rs1801275 (576 Q/R) polymorphisms in 317 childhood asthma patients and 351 healthy children as controls. Polymerase chain reaction amplification and sequencing was performed. The effects of interactions between the genes of interest and environmental factors were also analyzed. IL-4 rs2243250 and rs2070874 allele and genotype frequencies did not significantly differ between the asthma and control groups (P > 0.05), but those of IL-4R rs1801275 did (P < 0.05). The RR genotype and R allele of this IL-4R variant were significantly associated with asthma risk, with odds ratios (ORs; and 95% confidence intervals) of 2.97 (2.08-4.25) and 2.99 (2.32-3.85), respectively. Logistic regression analysis showed that the IL-4R 576 Q/R RR genotype demonstrated a positive interaction with environments associated with smoking or pets in its effect on asthma risk, with ORs of 2.18 (P = 0.02) and 2.29 (P = 0.01), respectively. Our results suggest that the IL-4R rs1801275 polymorphism is associated with childhood asthma, and the RR genotype confers a high risk of developing this condition. This variant exhibited positive interactions with environments in which smoking or pets were present in increasing the risk of childhood asthma.

The rs5934505 single nucleotide polymorphism (SNP) is associated with low testosterone and late-onset hypogonadism, but the rs10822184 SNP is associated with overweight and obesity in a Chinese Han population: a case-control study.

Low testosterone is associated with late-onset hypogonadism (LOH) and obesity. Recently, studies have shown that four single nucleotide polymorphisms (SNPs), rs12150660, rs727428, rs5934505, and rs10822184, are associated with testosterone levels in populations of European descent. Therefore, we investigated whether the SNP loci are related to low testosterone, LOH, or obesity in a Chinese Han population. Ruling out co-morbidities, DNA was prepared from 409 men (aged 40-65 years) with low serum testosterone (defined as total testosterone <11.6 nmol/L) and 1 : 1 normal controls (matched age, body mass index (BMI), and the same living area) who were selected from 6898 males. According to the same standards, 310 men with LOH and 1 : 1 normal controls were selected from 6898 males. Excluding the cases with an unreliable sequencing result, genetic analyses were performed. The minor allele frequencies of the SNP loci rs12150660, rs727428, rs5934505, and rs10822184 were 0.1%, 44.6%, 18.7%, and 38.9%, respectively. rs5934505 was associated with the serum total testosterone and calculated free testosterone (CFT) levels (p = 0.045 and p = 0.021). rs5934505 (C>T) was associated with an increased risk of low total testosterone, low CFT, and LOH and adjusted for other factors, with an odds ratio (OR) of 2.01 (1.34-3.01), 2.14 (1.42-3.20), and 1.64 (1.04-2.58). rs10822184 was significantly correlated with weight and BMI (p = 0.035 and p = 0.027). rs10822184 (T>C) was associated with an increased risk of overweight and obesity. We adjusted for other factors, with odds ratios (ORs) of 1.94 (1.36-2.78) and 1.56 (1.00-2.43). In summary, our study provided convincing evidence that rs5934505 (C>T) was associated with the risk of low testosterone and LOH in Chinese populations. We were the first to find that rs10822184 (T>C) was significantly correlated with the risk of overweight and obesity in Chinese populations. However, further large and functional studies are warranted to confirm our findings.

Characterization and expression analysis of microRNAs in Qira black sheep and Hetian sheep ovaries using Solexa sequencing.

The role of microRNAs (miRNAs) in the regulation of mammalian reproduction has been demonstrated previously. However, only a few studies have assessed the role of miRNAs in the reproduction processes of sheep. The elucidation of miRNA expression profiles in the ovaries of different sheep breeds representing fecundity extremes will be useful in understanding the roles of miRNAs in sheep reproduction. In this study, two small RNA libraries were constructed from ovary tissue taken from Qira black sheep and Hetian sheep during the estrous period and then sequenced using the Solexa sequencing method. We obtained 9,565,212 and 9,563,426 high-quality reads from Qira black sheep and Hetian sheep, respectively. In total, 531 miRNAs, including 98 putative miRNAs, were identified. Among the conserved miRNAs, 125 known miRNAs were significantly differentially expressed in the Qira black sheep and Hetian sheep libraries, with 24 upregulated and 101 downregulated in the Hetian sheep compared to the Qira black sheep. Four differentially expressed miRNAs were analyzed using real-time quantitative PCR to validate the reliability of the Solexa sequencing results. These results provide a foundation for future research on the regulation of miRNAs in sheep fertility and enrich the sheep miRNA databases.

Multiscale simulation of thin-film lubrication: free-energy-corrected coarse graining.

The quasicontinuum method was previously extended to the nonzero temperature conditions by implementing a free-energy correction on non-nodal atoms in coarse-grained solid systems to avoid the dynamical constraint, [Diestler, Wu, and Zeng, J. Chem. Phys. 121, 9279 (2004)]. In this paper, we combine the extended quasicontinuum method and an atomistic simulation to treat the monolayer film lubrication with elastic (nonrigid) substrates. It is shown that the multiscale method with the coarse-graining local elements in the merging regions between the atomistic and continuous descriptions of the substrates can reasonably predict the shear stress profile, the mean separation curve, and the transverse stress profile in the fully atomistic simulation for the tribological system. Moreover, when the nonlocal elements are placed in the merging regions, the inhomogeneous solid atoms in the near regions covered by the cut-off circles of the nonlocal elements replace the homogeneous ones at the equilibrium configuration for the free-energy correction on the non-nodal atoms. The treatment can cause an unphysical sliding between the near and far regions of the upper substrate. It is shown that if the free-energy correction on the non-nodal atoms in the coarse-grained merging regions is removed, the multiscale method can still well reproduce the shear stress profile, the mean separation curve, and the transverse stress profile obtained from the fully atomistic simulation for the system.

Kagome-like lattice of π-π stacked 3-hydroxyphenalenone on Cu(111).

We have identified a structurally complex double-layer of 3-hydroxyphenalenone on Cu(111), which exhibits Kagome lattice symmetry. A key feature is the perpendicular attachment of π-π stacked molecular dimers on top of molecules that are flat-lying on the substrate, representing a rare example of a three-dimensional arrangement of molecules on a two-dimensional surface.

Fundamental measure density functional theory study of liquid-vapor interface of dipolar and quadrupolar fluids.

We have studied interfacial structure and properties of liquid-vapor interfaces of dipolar fluids and quadrupolar fluids, respectively, using the classical density functional theory (DFT). Towards this end, we employ the fundamental measure DFT for a reference hard-sphere (HS) part of free energy and the modified mean field approximation for the correlation function of dipolar or quadrupolar fluid. At low temperatures we find that both the liquid-vapor interfacial density profile and orientational order parameter profile exhibit weakly damped oscillatory decay into the bulk liquid. At high temperatures the decay of interfacial density and order parameter profiles is entirely monotonic. The scaled temperature τ = 1 - T/T(c) that separates the two qualitatively different interfacial structures is in the range 0.10-0.15. At a given (dimensionless) temperature, increasing the dipolar or quadrupolar moment enhances the density oscillations. Application of an electric field (normal to the interface) will damp the oscillations. Likewise, at the given temperature, increasing the strength of any multipolar moment also increases the surface tensions while increasing the strength of the applied electric field will reduce the surface tensions. The results are compared with those based on the local-density approximations (LDA) for the reference HS part of free energy as well as with results of numerical experiments.

Two-dimensional crystallization of hexagonal bilayer with Moiré patterns.

Direct observation of crystallization dynamics in real space is of special interest to scientists in various disciplines. Although direct observation of transient structural transformation in a nanocrystalline system has been recently achieved using the state-of-the-art aberration-corrected transmission electron microscopy (AC-TEM), the small length scales of individual species in molecular systems still preclude routine observation of crystallization dynamics. Unidirectional packing of microbeads can serve as an experimental model system, as their dynamics can be observed and recorded readily in the laboratory due to their larger size and slower time scale. Herein, we present direct observation of a two-dimensional (2D) crystallization enabled by such a packing process. The direct imaging approach not only allows observation of the dynamics in a bead-by-bead fashion but also reveals intriguing phenomena, such as the formation of grain boundaries, disorder-order transitions, and the Moiré patterns which arise when two periodic monolayers are overlaid at certain angles. In addition, the imaging afforded by confocal microscopy facilitates a structural analysis of height-dependent polygonal tiling of the top monolayer, which has implication to the formation of 2D quasicrystals.

Nanochannel with uniform and Janus surfaces: shear thinning and thickening in surfactant solution.

On basis of molecular simulation of confined surfactant solutions, we show that by adding chemical patterns on the inner surface of nanochannels dynamical properties of the confined surfactant solutions could be modified from shear thinning to shear thickening. To this end, we select uniformly hydrophobic and hydrophilic surfaces as well as a stripe-patterned Janus surface as three prototype confining surfaces of nanochannels. In all three nanochannels, when the surfactant solution is under relatively low shear rates, it shears thin. Under moderate shear rates, a sharp decrease in the shear viscosity could occur due to surfactant morphology transition. Under relatively high shear rates, a shear-thinning-to-thickening transition can emerge due to the tendency of stratification normal to the confining surface. Our simulation study offers a guide to steering dynamic properties of surfactant fluids in nanofluidic devices through engineering surfaces of nanochannels by design.

Effects of fasting on hematologic and clinical chemical values in cynomolgus monkeys (Macaca fascicularis).

BACKGROUND: Fasting is an important pre-analytical factor that may affect clinical pathology parameters in toxicological and pharmacological studies. Little information is available on how fasting affects clinical pathology parameters in cynomolgus monkeys (Macaca fascicularis).The aim of this study was to evaluate the influence of fasting on clinical pathology parameters in healthy adult cynomolgus monkeys. METHODS: Five female and six male cynomolgus monkeys were fasted for 0, 8, 16, and 24 hours. Changes in body weight (BW), core hematologic, and serum clinical chemical parameters were evaluated. RESULTS: The BW significantly decreased after 24 hours of fasting. Significant decreases in red blood cell count, hemoglobin, hematocrit, and mean corpuscular volume and increases in mean cell hemoglobin and mean cell hemoglobin concentration were observed at 16 hours in males. In females, increasing the duration of fasting caused a significant time-dependent increase in platelets. Blood urea nitrogen showed significant decreases in female and male monkeys after fasting. Alkaline phosphatase increased in females after fasting. Aspartate transaminase significantly increased both in females and males at 8 hours. In females, alanine transaminase and lactate dehydrogenase significantly increased at 8 hours. Albumin significantly decreased in males 24 hours, but increased in females 16 hours after fasting. Serum glucose and triglyceride were not affected by fasting. Serum calcium decreased and inorganic phosphorus increased in males after fasting. CONCLUSION: These results suggested that clinical pathology data would vary after fasting. The decision to feed or fast before blood collection for clinical pathology tests should be made based on careful consideration.

First-principles study of methane dehydrogenation on a bimetallic Cu/Ni(111) surface.

We present density-functional theory calculations of the dehydrogenation of methane and CH(x) (x=1-3) on a Cu/Ni(111) surface, where Cu atoms are substituted on the Ni surface at a coverage of 14 monolayer. As compared to the results on other metal surfaces, including Ni(111), a similar activation mechanism with different energetics is found for the successive dehydrogenation of CH(4) on the Cu/Ni(111) surface. In particular, the activation energy barrier (E(act)) for CH-->C+H is found to be 1.8 times larger than that on Ni(111), while E(act) for CH(4)-->CH(3)+H is 1.3 times larger. Considering the proven beneficial effect of Cu observed in the experimental systems, our findings reveal that the relative E(act) in the successive dehydrogenation of CH(4) plays a key role in impeding carbon formation during the industrial steam reforming of methane. Our calculations also indicate that previous scaling relationships of the adsorption energy (E(ads)) for CH(x) (x=1-3) and carbon on pure metals also hold for several Ni(111)-based alloy systems.

Medium-sized double magic metal clusters: Al@Cu(54) (-) and Al@Ag(54) (-).

Medium-sized double magic metal clusters, Al@Ag(54) (-) and Al@Cu(54) (-), are predicted based on unbiased global search and density functional calculation. Both bimetallic core-shell clusters have icosahedral symmetry, and they are much lower in energies than all other low-lying isomers. In contrast, the icosahedral cluster Al@Au(54) (-) is a high-energy isomer. Both Al@Ag(54) (-) and Al@Cu(54) (-) exhibit appreciable gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and strong spherical aromaticity, which provide two additional evidences for the likelihood of their high stability. The simulated anion photoelectron spectra and optical absorption spectra are readily compared with future experiments.

Half-metallicity in hybrid BCN nanoribbons.

The established chemical synthetic strategy toward graphene nanoribbons has greatly prompted and justified the research of theoretical designs of novel materials based on graphene. In this paper, we report the novel half-metallicity in C and BN hybrid zigzag nanoribbons even though stand-alone C or BN nanoribbon possesses a finite band gap. By performing first-principles electronic-structure calculations, we find this unexpected half-metallicity in the hybrid nanostructures stems from a competition between the charge and spin polarizations, as well as from the pi orbital hybridization between C and BN. Molecular dynamics simulations indicate that the hybrid nanoribbons are stable. Our results point out a possibility of making spintronic devices solely based on nanoribbons and a new way of fabricating metal-free half metals.

Self-assembly of surfactants and polymorphic transition in nanotubes.

We study self-assembly and polymorphic transitions of surfactant molecules in water within a nanotube and the effect of water-nanotube interactions on the self-assembly morphologies. We present a simulation evidence of a cornucopia of polymorphic structures of surfactant assemblies--many of which have not been observed in bulk solutions--through adjusting the water-nanotube chemical interactions which range from hydrophilic to hydroneutral and to hydrophobic. The ability to control the morphologies of surfactant assemblies within nanoscale confinement can be used for patterning the interior surface of nanochannels for application in nanofluidics and nanomedical devices.

Search for lowest-energy structure of Zintl dianion Si(12)(2-), Ge(12)(2-), and Sn(12)(2-).

We perform an unbiased search for the lowest-energy structures of Zintl dianions (Si(12)(2-), Ge(12)(2-), and Sn(12)(2-)), by using the basin-hopping (BH) global optimization method combined with density functional theory geometric optimization. High-level ab initio calculation at the coupled-cluster level is used to determine relative stabilities and energy ranking among competitive low-lying isomers of the dianions obtained from the BH search. For Si(12)(2-), all BH searches (based on independent initial structures) lead to the same lowest-energy structure Si(12a)(2-), a tricapped trigonal prism (TTP) with C(s) group symmetry. Coupled-cluster calculation, however, suggests that another TTP isomer of Si(12c)(2-) is nearly isoenergetic with Si(12a)(2-). For Sn(12)(2-), all BH searches lead to the icosahedral structure I(h)-Sn(12a)(2-), i.e., the stannaspherene. For Ge(12)(2-), however, most BH searches lead to the TTP-containing Ge(12b)(2-), while a few BH searches lead to the empty-cage icosahedral structure I(h)-Ge(12a)(2-) (named as germaniaspherene). High-level ab initio calculation indicates that I(h)-Ge(12a)(2-) and TTP-containing Ge(12b)(2-) are almost isoenergetic and, thus, both may be considered as candidates for the lowest-energy structure at 0 K. Ge(12a)(2-) has a much larger energy gap (2.04 eV) between highest occupied molecular orbital and lowest unoccupied molecular orbital than Ge(12b)(2-) (1.29 eV), while Ge(12b)(2-) has a lower free energy than I(h)-Ge(12a)(2-) at elevated temperature (>980 K). The TTP-containing Si(12a)(2-) and Ge(12b)(2-) exhibit large negative nuclear independent chemical shift (NICS) value (approximately -44) at the center of TTP, indicating aromatic character. In contrast, germaniaspherene I(h)-Ge(12a)(2-) and stannaspherene I(h)-Sn(12a)(2-) exhibit modest positive NICS values, approximately 12 and 3, respectively, at the center of the empty cage, indicating weakly antiaromatic character.

Ab initio calculation of carbon clusters. II. Relative stabilities of fullerene and nonfullerene C24.

Chemical stabilities of six low-energy isomers of C24 derived from global-minimum search are investigated. The six isomers include one classical fullerene (isomer 1) whose cage is composed of only five- and six-membered rings (56-MRs), three nonclassical fullerene structures whose cages contain at least one four-membered ring (4-MR), one plate, and one monocyclic ring. Chemical and electronic properties of the six C24 isomers are calculated based on a density-functional theory method (hybrid PBE1PBE functional and cc-pVTZ basis set). The properties include the nucleus-independent chemical shifts (NICS), singlet-triplet splitting, electron affinity, ionization potential, and gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO) gap. The calculation suggests that the neutral isomer 2, a nonclassical fullerene with two 4-MRs, may be more chemically stable than the classical fullerene (isomer 1). Analyses of molecular orbital NICS show that the incorporations of 4-MRs into the cage considerably reduce paratropic contributions from HOMO, HOMO-1, and HOMO-2, which are mainly responsible for the sign change in NICS from positive for isomer 1 (42) to negative (-19) for isomer 2, although C24 clusters satisfy neither 4N+2 nor 2(N+1)2 aromaticity rule. Anion photoelectron spectra of four cage isomers, one plate, one monocyclic ring, and one tadpole isomer, as well as three bicyclic ring isomers are calculated. The simulated photoelectron spectra of mono- and bicyclic rings (with C1 symmetry) appear to match the measured HOMO-LUMO gap (between the first and second band in the experimental spectra) [S. Yang et al., Chem. Phys. Lett. 144, 431 (1988)]. Nevertheless, the nonclassical fullerene isomers 3 and 4 apparently also match the measured vertical detachment energy (2.90 eV) reasonably well. These results suggest possible coexistence of nonclassical fullerene isomers with the mono- and bicyclic ring isomers of C24(-) under the experimental conditions.

Structures and relative stability of medium- and large-sized silicon clusters. VI. Fullerene cage motifs for low-lying clusters Si(39), Si(40), Si(50), Si(60), Si(70), and Si(80).

We performed a constrained search, combined with density-functional theory optimization, of low-energy geometric structures of silicon clusters Si(39), Si(40), Si(50), Si(60), Si(70), and Si(80). We used fullerene cages as structural motifs to construct initial configurations of endohedral fullerene structures. For Si(39), we examined six endohedral fullerene structures using all six homolog C(34) fullerene isomers as cage motifs. We found that the Si(39) constructed based on the C(34)(C(s):2) cage motif results in a new leading candidate for the lowest-energy structure whose energy is appreciably lower than that of the previously reported leading candidate obtained based on unbiased searches (combined with tight-binding optimization). The C(34)(C(s):2) cage motif also leads to a new candidate for the lowest-energy structure of Si(40) whose energy is notably lower than that of the previously reported leading candidate with outer cage homolog to the C(34)(C(1):1). Low-lying structures of larger silicon clusters Si(50) and Si(60) are also obtained on the basis of preconstructed endohedral fullerene structures. For Si(50), Si(60), and Si(80), the obtained low-energy structures are all notably lower in energy than the lowest-energy silicon structures obtained based on an unbiased search with the empirical Stillinger-Weber potential of silicon. Additionally, we found that the binding energy per atom (or cohesive energy) increases typically >10 meV with addition of every ten Si atoms. This result may be used as an empirical criterion (or the minimal requirement) to identify low-lying silicon clusters with size larger than Si(50).