Effects of C/N ratio on N2O emissions and nitrogen functional genes during vegetable waste composting.

Nitrous oxide (N2O) generation during composting not only leads to losses of nitrogen (N) but also reduces the agronomic values and environmental benefits of composting. This study aimed to investigate the effect of the C/N ratio on N2O emissions and its underlying mechanisms at the genetic level during the composting of vegetable waste. The experiment was set up with three treatments, including low C/N treatment (LT, C/N = 18), middle C/N treatment (MT, C/N = 30), and high C/N treatment (HT, C/N = 50). The results showed that N2O emission was mainly concentrated in the cooling and maturation periods, and the cumulative N2O emissions decreased as the C/N ratio increased. Specifically, the cumulative N2O emission was 57,401 mg in LT, significantly higher than 2155 mg in MT and 1353 mg in HT. Lowering the C/N ratio led to increasing TN, NH4+-N, and NO3--N contents throughout the composting process. All detected nitrification-related gene abundances in LT continued to increase during composting, significantly surpassing those in MT during the cooling period. By contrast, in HT, there was a slight increase in the abundance of detected nitrification-related genes but a significant decrease in the abundance of narG, napA, and norB genes in the thermophilic and cooling periods. The structural equation model revealed that hao and nosZ genes were vital in N2O emissions. In conclusion, increasing the C/N ratio effectively contributed to N2O reduction during vegetable waste composting.

An FeCl3-catalyzed three-component reaction for the synthesis of ß-(1,2,3-triazolyl)-ketones using DMF as a one-carbon source.

An FeCl3-catalyzed oxidative condensation of NH-1,2,3-triazoles, aryl methyl ketones (or acetophenones) and DMF (N,N-dimethylformamide) for the synthesis of ß-(1,2,3-triazolyl)-ketones was developed. DMF serves as a one-carbon source, and the resulting products display diverse reaction selectivity, highlighting the existence of distinct approaches.

Causal influence of celiac disease on the risk of sarcoidosis: A Mendelian randomization study.

Observational research shows a link between celiac disease (CeD) and sarcoidosis, but the causal link between CeD and sarcoidosis is still unknown. A two-sample Mendelian randomization (MR) study was conducted to ascertain the causal connection between the 2 disorders. In our two-sample MR analysis, we identified independent genetic variants associated with CeD using publicly accessible GWAS data from people of European ancestry. Summary data for sarcoidosis were obtained from the FinnGen Consortium, the UK-Biobank, and a large GWAS dataset. To assess the association between CeD and sarcoidosis, our MR analysis used inverse variance weighted (IVW) as the primary method, incorporating the MR-Egger, weighted median (WM), and MR-PRESSO (outliers test) as a complementary method. In order to ensure that the findings were reliable, several sensitivity analyses were performed. Our study indicated that CeD had a significant causal relationship with sarcoidosis (IVW odds ratio (OR) = 1.13, 95% confidence interval (CI): 1.07-1.20, P = 5.58E-05; WM OR = 1.12, 95% CI: 1.03-1.23, P = 1.03E-02; MR-Egger OR = 1.07, 95% CI: 0.96-1.19, P = 2.20E-01). Additionally, we obtain the same results in the duplicated datasets as well, which makes our results even more reliable. The results of this investigation did not reveal any evidence of horizontal pleiotropy or heterogeneity. Our MR analysis showed a causal effect between CeD and an elevated risk of sarcoidosis. Further study is still needed to confirm the findings and look into the processes underlying these relationships.

Straw Addition Enhances Crop Yield, Soil Aggregation, and Soil Microorganisms in a 14-Year Wheat-Rice Rotation System in Central China.

Straw return utilizes waste resources to reduce the use of chemical fertilizers worldwide. However, information is still lacking on the relative impact of straw return on soil fertility, the nutrient composition of different soil aggregates, and soil microbial communities. Therefore, this study aimed to understand the effects of different management practices on the crop yield, soil fertility, and soil community composition in a 14-year wheat-rice rotation system. The treatments included a control (without fertilizer and straw addition), chemical fertilization (NPK), straw return without fertilizer (S), and straw addition with chemical fertilizer (NPKS). The results showed that NPKS improved the wheat and rice yield by 185.12% and 88.02%, respectively, compared to the CK treatment. Additionally, compared to the CK treatment, the N, P, and K contents of the wheat stem were increased by 39.02%, 125%, and 20.23% under the NPKS treatment. Compared to the CK treatment, SOM, TN, TP, AN, AP, AK, CEC, AFe, AMn, ACu, and AZn were increased by 49.12%, 32.62%, 35.06%, 22.89%, 129.36%, 48.34%, 13.40%, 133.95%, 58.98%, 18.26% and 33.33% under the NPKS treatment, respectively. Moreover, straw addition promoted the creation and stabilization of macro-aggregates in crop soils. The relative abundance of macro-aggregates (0.25-2 mm) increased from 37.49% to 52.97%. Straw addition was associated with a higher proportion of aromatic and carbonyl carbon groups in the soil, which, in turn, promoted the formation of macro-aggregates. Redundancy analysis showed that straw return significantly increased the microbial community diversity. These findings demonstrate that straw addition together with chemical fertilizer could increase the crop yield by improving soil fertility, soil aggregate stability, and the diversity of fungi.

TREM2 deficiency impairs the energy metabolism of Schwann cells and exacerbates peripheral neurological deficits.

Triggering receptor expressed on myeloid cells-2 (TREM2) has been implicated in susceptibility to neurodegenerative disease. Schwann cells (SCs), the predominant glial cell type in the peripheral nervous system (PNS), play a crucial role in myelination, providing trophic support for neurons and nerve regeneration. However, the function of TREM2 in SCs has not been fully elucidated. Here, we found that TREM2 is expressed in SCs but not in neurons in the PNS. TREM2 deficiency leads to disruption of glycolytic flux and oxidative metabolism in SCs, impairing cell proliferation. The energy crisis caused by TREM2 deficiency triggers mitochondrial damage and autophagy by activating AMPK and impairing PI3K-AKT-mTOR signaling. Combined metabolomic analysis demonstrated that energic substrates and energy metabolic pathways were significantly impaired in TREM2-deficient SCs. Moreover, TREM2 deficiency impairs energy metabolism and axonal growth in sciatic nerve, accompanied by exacerbation of neurological deficits and suppression of nerve regeneration in a mouse model of acute motor axonal neuropathy. These results indicate that TREM2 is a critical regulator of energy metabolism in SCs and exerts neuroprotective effects on peripheral neuropathy. TREM2 deficiency impairs glycolysis and oxidative metabolism in Schwann cells, resulting in compromised cell proliferation. The energy crisis caused by TREM2 deficiency induces mitochondrial damage and autophagy by activating AMPK and impairing PI3K-AKT-mTOR signaling. Moreover, TREM2 deficiency disrupts the energy metabolism of the sciatic nerve and impairs support for axonal regeneration, accompanied by exacerbation of neurological deficits and suppression of nerve regeneration in a mouse model of acute motor axonal neuropathy (by FigDraw).

Enhanced Bacterial Cuproptosis-Like Death via Reversal of Hypoxia Microenvironment for Biofilm Infection Treatment.

A recently emerging cell death pathway, known as copper-induced cell death, has demonstrated significant potential for treating infections. Existing research suggests that cells utilizing aerobic respiration, as opposed to those reliant on glycolysis, exhibit greater sensitivity to copper-induced death. Herein, a MnO2 -loaded copper metal-organic frameworks platform is developed denoted as MCM, to enhance bacterial cuproptosis-like death via the remodeling of bacterial respiratory metabolism. The reversal of hypoxic microenvironments induced a cascade of responses, encompassing the reactivation of suppressed immune responses and the promotion of osteogenesis and angiogenesis. Initially, MCM catalyzed O2 production, alleviating hypoxia within the biofilm and inducing a transition in bacterial respiration mode from glycolysis to aerobic respiration. Subsequently, the sensitized bacteria, characterized by enhanced tricarboxylic acid cycle activity, underwent cuproptosis-like death owing to increased copper concentrations and aggregated intracellular dihydrolipoamide S-acetyltransferase (DLAT). The disruption of hypoxia also stimulated suppressed dendritic cells and macrophages, thereby strengthening their antimicrobial activity through chemotaxis and phagocytosis. Moreover, the nutritional effects of copper elements, coupled with hypoxia alleviation, synergistically facilitated the regeneration of bones and blood vessels. Overall, reshaping the infection microenvironment to enhance cuproptosis-like cell death presents a promising avenue for eradicating biofilms.

Mpox virus Clade IIb infected Cynomolgus macaques via mimic natural infection routes closely resembled human mpox infection.

Generating an infectious non-human primate (NHP) model using a prevalent monkeypox virus (MPXV) strain has emerged as a crucial strategy for assessing the efficacy of vaccines and antiviral drugs against human MPXV infection. Here, we established an animal model by infecting cynomolgus macaques with the prevalent MPXV strain, WIBP-MPXV-001, and simulating its natural routes of infection. A comprehensive analysis and evaluation were conducted on three animals, including monitoring clinical symptoms, collecting hematology data, measuring viral loads, evaluating cellular and humoral immune responses, and examining histopathology. Our findings revealed that initial skin lesions appeared at the inoculation sites and subsequently spread to the limbs and back, and all infected animals exhibited bilateral inguinal lymphadenopathy, eventually leading to a self-limiting disease course. Viral DNA was detected in post-infection blood, nasal, throat, rectal and blister fluid swabs. These observations indicate that the NHP model accurately reflects critical clinical features observed in human MPXV infection. Notably, the animals displayed clinical symptoms and disease progression similar to those of humans, rather than a lethal outcome as observed in previous studies. Historically, MPXV was utilized as a surrogate model for smallpox. However, our study contributes to a better understanding of the dynamics of current MPXV infections while providing a potential infectious NHP model for further evaluation of vaccines and antiviral drugs against mpox infection. Furthermore, the challenge model closely mimics the primary natural routes of transmission for human MPXV infections. This approach enhances our understanding of the precise mechanisms underlying the interhuman transmission of MPXV.

Phosphate additives promote humic acid carbon and nitrogen skeleton formation by regulating precursors and composting bacterial communities.

This study aimed to compare the effect of different phosphate additives including superphosphate (CP) and MP [Mg(OH)2 + H3PO4] on nitrogen conversion, humus fractions formation and bacterial community in food waste compost. The results showed the ratio of humic acid nitrogen in total nitrogen (HA-N/TN) in CP increased by 49 %. Ammonium nitrogen accumulation was increased by 75 % (CP) and 44 % (MP). Spectroscopic techniques proved that phosphate addition facilitated the formation of complex structures in HA. CP enhanced the dominance of Saccharomonospora, while Thermobifida and Bacillus were improved in MP. Structural equation modeling and network analysis demonstrated that ammonium nitrogen can be converted to HA-N and has positive effects on bacterial composition, reducing sugars and amino acids, especially in CP with more clustered network and synergic bacterial interactions. Therefore, the addition of phosphate provides a new idea to regulate the retained nitrogen toward humification in composting.

Immunogenicity and effectiveness of an mRNA therapeutic vaccine for HPV-related malignancies.

Human papillomavirus (HPV) infections account for several human cancers. There is an urgent need to develop therapeutic vaccines for targeting preexisting high-risk HPV (such as HPV 16 and 18) infections and lesions, which are insensitive to preventative vaccines. In this study, we developed a lipid nanoparticle-formulated mRNA-based HPV therapeutic vaccine (mHTV), mHTV-02, targeting the E6/E7 of HPV16 and HPV-18. mHTV-02 dramatically induced antigen-specific cellular immune response and robust memory T-cell immunity in mice, besides significant CD8+ T-cell infiltration and cytotoxicity in TC-1 tumors expressing HPV E6/E7, resulting in tumor regression and prolonged survival in mice. Moreover, evaluation of routes of administration found that intramuscular or intratumoral injection of mHTV-02 displayed significant therapeutic effects. In contrast, intravenous delivery of the vaccine barely showed any benefit in reducing tumor size or improving animal survival. These data together support mHTV-02 as a candidate therapeutic mRNA vaccine via specific administration routes for treating malignancies caused by HPV16 or HPV18 infections.

Deciphering the carbon and nitrogen component conversion in humification process mediated by distinct microbial mechanisms in composting from different domestic organic wastes.

This study aimed to compare the process of maturity and humus fraction evolution as well as bacterial community dynamics in composting from different domestic organic wastes (food waste (FW), and vegetable waste (VW)) and decipher the key biotic influencing factors of humic acid formation through correlation analysis and ecological network. The results showed that organic carbon components in FW with high ratio of soluble organic carbon and hemicellulose were more easily to be degraded in composting compared to VW. After 30 days of composting, the content of HA-C generated by VW was 35.41%, higher than 29.01% of FW, and the growth rate of HA-C generated was 38.42% and 28.34%, respectively. PARAFAC analysis showed that the structure of HA generated in VW was more complex, and the proportion of humic acid-like components (C3 + C4) was 60.32%, while FW only accounted for 43.86%. However, the evolution growth rate of aromatic components in HA in FW was 26.88% in 30 days of compost, which was higher than 15.17% in VW. High-throughput sequencing indicated that Lactobacillus was the initial dominated genera in composting from different domestic wastes. Thermobifida, Thermovum, and Pusillimas as well as Aeribacillus were core bacterial genera that promoted the humification process in FW and VW, respectively. Network analysis showed that there was higher bacterial interacted connection degree and complexity in FW compared to VW. This study was of great significance for optimizing organics conversion and humification efficiency of household waste composting.

Quorum Sensing Interference Assisted Therapy-Based Magnetic Hyperthermia Amplifier for Synergistic Biofilm Treatment.

Biofilms offer bacteria a physical and metabolic barrier, enhancing their tolerance to external stress. Consequently, these biofilms limit the effectiveness of conventional antimicrobial treatment. Recently, quorum sensing (QS) has been linked to biofilm's stress response to thermal, oxidative, and osmotic stress. Herein, a multiple synergistic therapeutic strategy that couples quorum sensing interference assisted therapy (QSIAT)-mediated enhanced thermal therapy with bacteria-triggered immunomodulation in a single nanoplatform, is presented. First, as magnetic hyperthermia amplifier, hyaluronic acid-coated ferrite (HA@MnFe2 O4 ) attenuates the stress response of biofilm by down-regulating QS-related genes, including agrA, agrC, and hld. Next, the sensitized bacteria are eliminated with magnetic heat. QS interference and heat also destruct the biofilm, and provide channels for further penetration of nanoparticles. Moreover, triggered by bacterial hyaluronidase, the wrapped hyaluronic acid (HA) decomposes into disaccharides at the site of infection and exerts healing effect. Thus, by reversing the bacterial tissue invasion mechanism for antimicrobial purpose, tissue regeneration following pathogen invasion and thermal therapy is successfully attained. RNA-sequencing demonstrates the QS-mediated stress response impairment. In vitro and in vivo experiments reveal the excellent antibiofilm and anti-inflammatory effects of HA@MnFe2 O4 . Overall, QSIAT provides a universal enhancement strategy for amplifying the bactericidal effects of conventional therapy via stress response interference.

Force-Regulated Spontaneous Conformational Changes of Integrins α5ß1 and αVß3.

Integrins are cell surface nanosized receptors crucial for cell motility and mechanosensing of the extracellular environment, which are often targeted for the development of biomaterials and nanomedicines. As a key feature of integrins, their activity, structure and behavior are highly mechanosensitive, which are regulated by mechanical forces down to pico-Newton scale. Using single-molecule biomechanical approaches, we compared the force-modulated ectodomain bending/unbending conformational changes of two integrin species, α5ß1 and αVß3. It was found that the conformation of integrin α5ß1 is determined by a threshold head-to-tail tension. By comparison, integrin αVß3 exhibits bistability even without force and can spontaneously transition between the bent and extended conformations with an apparent transition time under a wide range of forces. Molecular dynamics simulations observed almost concurrent disruption of ∼2 hydrogen bonds during integrin α5ß1 unbending, but consecutive disruption of ∼7 hydrogen bonds during integrin αVß3 unbending. Accordingly, we constructed a canonical energy landscape for integrin α5ß1 with a single energy well that traps the integrin in the bent state until sufficient force tilts the energy landscape to allow the conformational transition. In contrast, the energy landscape of integrin αVß3 conformational changes was constructed with hexa-stable intermediate states and intermediate energy barriers that segregate the conformational change process into multiple small steps. Our study elucidates the different biomechanical inner workings of integrins α5ß1 and αVß3 at the submolecular level, helps understand their mechanosignaling processes and how their respective functions are facilitated by their distinctive mechanosensitivities, and provides useful design principles for the engineering of protein-based biomechanical nanomachines.

Integrating work into life helps reduce residential greenhouse gas emissions.

Work from home (WFH) creates work-life integration by moving work into traditional life at home, but its influence on residential greenhouse gas (GHG) emissions remains unclear. In this study, an activity-based bottom-up model was developed to analyze the time-use patterns (activity durations and timeline of a typical day) of participants under WFH and traditional home life and to quantify their residential GHG emissions. Under WFH, participants generated an average of 9.03 kg CO2e/person/day, primarily attributed to space heating and cooling, cooking, grooming, work, and watching TV and movies. Notably, the GHG footprints varied across groups (8.08-9.93 kg CO2e/person/day) due to different work and household responsibilities and leisure time and varied with climate region (4.99-10.63 kg CO2e/person/day) because of emission factors of electricity, space heating and cooling, and cooking. Compared with traditional life at home (10.06 kg CO2e/person/day), WFH participants spent less time on almost all major activities (especially sleeping and watching TV and movies) to focus on work, enabling an 11.34% (1.02 kg CO2e/person/day) mitigation of GHG emissions. The reductions also varied by group and climate region, mainly associated with laundry, cooking, and watching TV and movies. Opportunities to reduce GHG emissions under WFH lie in targeting key activities, balancing the time spent on various activities, and developing group- and spatial-specific strategies. This study provides a systematic and high-resolution estimation of residential GHG emissions under WFH and traditional home life, with a complete system boundary, activity-specific considerations, and countrywide understanding. The findings reveal the environmental impact of work-life integration from the residential perspective and can aid residents and policymakers in utilizing decarbonization opportunities to advance low-carbon living under WFH.

A lung-selective delivery of mRNA encoding broadly neutralizing antibody against SARS-CoV-2 infection.

The respiratory system, especially the lung, is the key site of pathological injury induced by SARS-CoV-2 infection. Given the low feasibility of targeted delivery of antibodies into the lungs by intravenous administration and the short half-life period of antibodies in the lungs by intranasal or aerosolized immunization, mRNA encoding broadly neutralizing antibodies with lung-targeting capability can perfectly provide high-titer antibodies in lungs to prevent the SARS-CoV-2 infection. Here, we firstly identify a human monoclonal antibody, 8-9D, with broad neutralizing potency against SARS-CoV-2 variants. The neutralization mechanism of this antibody is explained by the structural characteristics of 8-9D Fabs in complex with the Omicron BA.5 spike. In addition, we evaluate the efficacy of 8-9D using a safe and robust mRNA delivery platform and compare the performance of 8-9D when its mRNA is and is not selectively delivered to the lungs. The lung-selective delivery of the 8-9D mRNA enables the expression of neutralizing antibodies in the lungs which blocks the invasion of the virus, thus effectively protecting female K18-hACE2 transgenic mice from challenge with the Beta or Omicron BA.1 variant. Our work underscores the potential application of lung-selective mRNA antibodies in the prevention and treatment of infections caused by circulating SARS-CoV-2 variants.

Dietary Effects of Lipid and Protein Levels on Growth, Feed Utilization, Lipid Metabolism, and Antioxidant Capacity of Triploid Rainbow Trout (Oncorhynchus mykiss).

This study investigated the dietary effects of lipid and protein levels on growth performance, feed utilization, body composition, lipid metabolism, and antioxidant capacity of triploid rainbow trout, Oncorhynchus mykiss. A 3 × 2 two-factor design was conducted with three crude lipid levels of 4%, 9%, and 14% (L4, L9, and L14) and two crude protein levels of 44%, 49% (P44, P49). Therefore, a total of six diets were prepared as P44/L4, P44/L9, P44/L14, P49/L4, P49/L9, and P49/L14. Triploid rainbow trout (initial body weight 65.0 ± 0.1 g) were fed one of the six diets for 80 days. The results showed that weight gain (WG), protein retention (PR), and protein efficiency rate (PER) significantly increased with increasing the dietary lipid level at the same crude protein level, while feed conversion ratio (FCR) and hepatosomatic index significantly decreased (P < 0.05). At the same lipid level, there was no difference in WG, FCR, PR, PER between 44% and 49% crude protein group (P > 0.05). The P49/L14 group had the highest WG (374.6%) and lowest FCR (1.25), while P44/L14 group had the highest PER (1.80) and PR (25.06%) with similar WG and FCR to P49/L14 group. The crude lipid contents in whole fish were significantly higher in the L14 group than those in the L4 and L9 groups (P < 0.05). Muscle n-3 PUFAs, n-6 PUFAs, and PUFAs levels were positively correlated with dietary lipid level, while n-6 PUFAs was negatively correlated with dietary protein level. Dietary protein, dietary lipid, and their interaction significantly affected hepatic malondialdehyde (MDA) content, aspartate aminotransferase, lipase (LPS), and fatty acid synthase (FAS) activities (P < 0.05). In both P44 and P49 groups, LPS and FAS activities increased with increasing the dietary lipid level. MDA content significantly decreased in the P44 group and increased in the P49 group with increasing the dietary lipid level (P < 0.05). As dietary protein level increased, serum total cholesterol level increased, while hepatic phosphoenolpyruvate carboxykinase activity decreased. With increasing the dietary lipid level, total superoxide dismutase, catalase, total nitric oxide synthase, and fructose-1,6-bisphosphatase activities showed an increasing trend, while the opposite was true for alanine aminotransferase activity. In conclusion, based on growth performance and feed utilization, dietary protein level of 44% and dietary lipid level of 14% (measured value, 43.71% and 13.62%) were suggested for young triploid rainbow trout.

Acupuncture on "Huantiao" (GB30) and "Yanglingquan" (GB34) acupoints promotes nerve regeneration in mice model of peripheral nerve injury.

Objective: To investigate the effects of acupuncture on promoting nerve regeneration in mice with sciatic nerve crushed injury, an animal model of peripheral nerve injury (PNI). Methods: Acupuncture was performed on the "Huantiao" (GB30) and "Yanglingquan" (GB34) acupoints in PNI mice model for 2 weeks. Gait analysis, toe spreading test, electrophysiological test, toluidine blue staining and immunostaining of myelin basic protein (MBP), neurofilament-200 (NF200), p75 neurotrophin receptor (p75NTR), and growth associated protein-43 (GAP43) were respectively performed to investigate the effects of acupuncture on crushed sciatic nerve. Results: Acupuncture stimulation of "Huantiao" (GB30) and "Yanglingquan" (GB34) acupoints promoted the recovery of motor function and electrophysiological function in PNI mice model, which was indicated by a better gait level, toe spreading level and CMAP value in acupuncture group. The number of myelinated nerve fibers and the fluorescence intensity of MBP, NF200, p75NTR and GAP43 staining demonstrated that the acupuncture stimulation promoted the regeneration of injured nerves in PNI mice model. Conclusion: Acupuncture significantly promoted the functional and morphological recovery of crushed sciatic nerve via promoting the expression of p75NTR in Schwann cells.

Allografts are not necessary for displaced proximal humeral fractures in patients less than 65 years old, a retrospective cohort study.

INTRODUCTION: Displaced proximal humeral fractures (PHF) are frequently treated with locking plates to achieve osteosynthesis. Bone grafts are used as augmentation techniques to improve stability in osteoporotic patients. However, there has been little research into whether bone grafts are necessary for patients younger than 65 years old. This study compared radiographic and clinical outcomes between PHFs augmented with bone grafts or not in a younger population. METHODS: Between January 2016 and June 2020, 91 patients treated with a locking plate alone (LP), and 101 patients treated with locking plates augmented with bone grafts (BG) were analyzed. Potential confounding factors for outcomes were adjusted by propensity score-matching analyses. For the retrospective cohort study, 62 patients from each group were evaluated for radiographic outcomes and clinical outcomes and compared. RESULTS: Sixth-two patients in each group, both with a mean age of 52 years old, were with a mean follow-up time of 25 months in the LP group and 26 months in the BG group. There was no difference in demographic or surgical characteristics between the two groups after propensity score-matching. With regard to radiographic outcomes, the changes in neck-shaft angle (-5.1 ± 4.9 vs. -3.1 ± 5.3, p = 0.015) and humeral head height (-1.5 ± 2.5 vs. -0.4 ± 2.7, p = 0.002) were more obvious in the BG group. However, regarding functional outcomes, there were no significant differences between the two groups in DASH score, Constant-Murley score, or VAS score. Moreover, the complication rate was not significantly different between two groups. DISCUSSION: Allografts only provide minor improvements of stability in radiography for patients less than 65 years old after locking plate fixation of PHFs, but don't improve shoulder function, relieve pain or reduce complications. We concluded that allografts are unnecessary for younger patients with displaced PHFs.

Nonanatomic healing of the greater tuberosity after plating in proximal humeral fractures: a case control study.

BACKGROUND: Open reduction and plate internal fixation (ORIF) is one of the most common treatment methods for proximal humeral fractures. Complications associated with the greater tuberosity (GT) are rarely reported, therefore, the purpose of this study was to analyze the complications associated with the GT and the risk factors after locked-plate internal fixation. METHODS: We retrospectively analyzed the medical and radiographic data of patients with proximal humeral fractures involving the GT treated with locking plates between January 2016 and July 2019. We divided all patients into two groups, the anatomic GT healing group and the nonanatomic GT healing group, depending on the radiographic outcomes of the GT. Clinical outcome was assessed by the Constant scoring system. Potential risk factors included preoperative and intraoperative factors. Preoperative factors included sex, age, body mass index, fracture type, fracture-dislocation, proximal humeral bone mineral density, humeral head extension, hinge integrity, comminuted GT, volume and surface area of the main GT fragment, and displacement of the main GT fragment. Intraoperative factors were adequate medial support, residual head-shaft displacement, head-shaft angle and residual GT displacement. Univariate logistic regression and multivariate logistic regression were used to identify risk factors. RESULTS: There were 207 patients (130 women and 77 men; mean age, 55 years). GT anatomic healing was observed in 139 (67.1%) patients and nonanatomic healing in 68 (32.9%). Patients with GT nonanatomic healing had significantly inferior Constant scores than those with GT anatomic healing (75.0 ± 13.9 vs. 83.9 ± 11.8, P < 0.001). Patients with high GT malposition had worse Constant scores than patients with low GT malposition (73.3 ± 12.7 vs. 81.1 ± 11.4, P = 0.039). The multivariate logistic model showed that GT fracture characteristics were not risk factors for nonanatomic GT healing, while residual GT displacement was. CONCLUSIONS: Nonanatomic healing of the GT is a high-rate complication of proximal humeral fractures, resulting in inferior clinical outcomes, especially for high GT malposition. Fracture characteristics of the GT are not risk factors for GT nonanatomic healing and GT comminution should not be regarded as a contraindication to ORIF for proximal humeral fractures.