Comparison of outcomes between single- and multiple-perforator-based free perforator flaps: A systematic review and meta-analysis.

BACKGROUND: Perforator-based free perforator flaps have become an important tool for the reconstruction of tissue defects. The effect of the number of perforators on the outcomes of perforator flaps has been widely debated. This study aimed to compare the outcomes of single- and multiple-perforator-based free perforator flaps in free-flap reconstruction. METHODS: We searched PubMed, Web of Science, EMBASE, Chinese BioMedical Literature Database (CBM), Cochrane Library, and clinicaltrials.gov between January 2000 and June 2021 to identify studies that reported data on the outcomes of free perforator flaps. Two authors individually extracted data and performed quality assessment. Outcomes, including partial flap loss, total loss, fat necrosis, arterial insufficiency, venous insufficiency, hemorrhage and hematoma, wound dehiscence at recipient sites and donor site complications, were evaluated. RESULTS: Thirty-two studies with 2498 flaps were included in our analysis. No significant difference was found in the rates of partial loss and arterial insufficiency of flaps, hemorrhage and hematoma, wound dehiscence at recipient sites and donor site complications. However, the multiple-perforator group showed significantly lower rates of total loss (relative risk [RR] = 1.08, 95% confidence interval [CI]: 0.78-1.79, p = .754), fat necrosis (RR = 1.79, 95% [CI]: 1.36-2.36, p = .000) and venous insufficiency (RR = 1.72, 95% CI: 1.07-2.79, p = .026) than the single-perforator group. CONCLUSION: The rates of total loss, fat necrosis and venous insufficiency in the multiple-perforator group were lower than those in the single-perforator group. Hence, we recommend that multiple perforators be included in the free perforator flap when appropriate, to yield better clinical outcomes in reconstruction.

Atomic Structural Evolution of Single-Layer Pt Clusters as Efficient Electrocatalysts.

The rational synthesis of single-layer noble metal directly anchored on support materials is an elusive target to accomplish for a long time. This paper reports well-defined single-layer Pt (Pt-SL) clusters anchored on ultrathin TiO2 nanosheets-as a new frontier in electrocatalysis. The structural evolution of Pt-SL/TiO2 via self-assembly of single Pt atoms (Pt-SA) is systematically recorded. Significantly, the Pt atoms of Pt-SL/TiO2 possess a unique electronic configuration with PtPt covalent bonds surrounded by abundant unpaired electrons. This Pt-SL/TiO2 catalyst presents enhanced electrochemical performance toward diverse electrocatalytic reactions (such as the hydrogen evolution reaction and the oxygen reduction reaction) compared with Pt-SA, multilayer Pt nanoclusters, and Pt nanoparticles, suggesting an efficient new type of catalyst that can be achieved by constructing single-layer atomic clusters on supports.

The Effect of Medial Sural Artery Perforator Flap on Reconstruction of Soft Tissue Defects: A Meta-Analysis With Multiple Free Soft Flaps.

BACKGROUND: With the gradual popularity of relatively novel medial sural artery perforator flap (MSAPF), robust studies are needed to compare the surgical outcomes of MSAPF versus multiple free soft flaps (MFSFs) to verify the advantages and disadvantages of MSAPF. METHODS: The authors searched PubMed, Web of Science, EMBASE, Cochrane Library, Chinese BioMedical Literature Database (CBM), and China National Knowledge Infrastructure (CNKI) until September, 2020, to identify studies that compared surgical outcomes of MSAPF and MFSFs. Two authors followed the PRISMA guidelines, individually extracted the data and performed the quality assessments. Survival rate of flaps, satisfaction degree of patients in recipient and donor site, skin grafting, and morbidity of recipient and donor site were evaluated. RESULTS: A total of 441 cases from 7 studies were included in our analysis. No significant differences were found regarding survival rate of flaps, recipient morbidity, and recipient satisfaction degree between the 2 groups. However, MSAPF group was significantly superior to MFSFs group in terms of skin grafting, morbidity, and satisfaction degree of donor site. CONCLUSION: Our meta-analysis showed that the MSPAF and MFSFs groups were similar in terms of survival rate of flaps, recipient morbidity, and recipient satisfaction degree. Medial sural artery perforator flap group was superior to MFSFs group in terms of morbidity and satisfaction degree of donor site. The results may prove that MSAPF is gaining popularity for a reason and is a good choice for repairing soft tissue defects.

High-performance natural-sunlight-driven Ag/AgCl photocatalysts with a cube-like morphology and blunt edges via a bola-type surfactant-assisted synthesis.

Ag/AgCl-based structures have recently been receiving considerable attention as visible-light-driven plasmonic photocatalysts, wherein the fabrication of Ag/AgCl species shaped with an anisotropic morphology is considered to be an efficient way to enhance their performances. While the past decade has witnessed great progress in this direction, it is still strongly desired to initiate a green and low-cost protocol for the synthesis of Ag/AgCl based structures with high catalytic activity. Using a surfactant-assisted synthesis protocol, wherein a cationic bola-type surfactant of chloride counteranions serves both as a reactant (namely, source of chlorine) for the generation of AgCl structures and as a directing template to assist the formation of anisotropic structures, we herein report that cube-like Ag/AgCl with blunt edges could be fabricated simply by dropping an aqueous solution of silver nitrate into an ethanol solution of the hexane-1,6-bis(trimethylammonium chloride) surfactant. Importantly, compared to the sphere-like counterparts manufactured using a conventional tadpole surfactant, the as-fabricated cube-like structures exhibit substantially improved catalytic performances under visible-light or natural-sunlight irradiation. It has been revealed that photogenerated holes might serve as the main active species during the catalytic process. Meanwhile, our results have disclosed that in contrast to the sphere-like Ag/AgCl structures, the as-constructed cube-like structures are relatively enriched with high-index AgCl facets of smaller hole effective mass, which promote a faster carrier transfer, facilitate the migration of the photogenerated holes to the surface to be involved in photocatalytic reactions, and suppress carrier recombination, leading to their enhanced photocatalytic performances. Considering the tremendous diversity of surfactants (bola-, gemini-, polymeric surfactants etc.) with various halide counteranions and their sophisticated template effects, our new strategy might open up new opportunities for silver/silver halide (Ag/AgX, X = Cl, Br, and I)-based plasmonic structures with various morphologies and with superior light-to-chemical energy conversion capability.

Comparison of Internal Jugular Vein System Anastomosis and External Jugular Vein System Anastomosis in Free Flaps for Head and Neck Reconstruction: A Meta-Analysis.

PURPOSE: The purpose of the present study was to investigate the differences in postoperative thrombosis and flap failure between internal jugular vein (IJV) system anastomosis and external jugular vein (EJV) system anastomosis in free flaps for the reconstruction of head and neck defects. MATERIALS AND METHODS: We searched PubMed, Web of Science, EMBASE, Chinese BioMedical Literature Database, and other databases until March 2019 for studies that had reported data for anastomosis for the 2 different venous systems in the microvascular free-flap reconstruction of head and neck defects. We assessed thrombosis and flap failure in patients undergoing anastomosis of the IJV system and patients undergoing anastomosis of the EJV system. RESULTS: Nine studies with a total of 2051 patients with venous anastomosis were included in the present meta-analysis. IJV system anastomosis showed a significantly lower incidence of venous thrombosis than did the EJV system (relative risk [RR], 0.55; 95% confidence interval [CI], 0.37 to 0.82). Eight studies were included in the analysis of the flap failure rate, which showed a lower failure rate for the IJV system anastomosis than for the EJV system (RR, 0.59; 95% CI, 0.35 to 1.00). CONCLUSIONS: The incidence of thrombosis and flap failure after venous anastomosis in the IJV system was lower than that in the EJV system. The results from the present study have shown that the IJV system should be the first choice for venous anastomosis in the reconstruction of free flaps.

Solar-Driven Nitrogen Fixation Catalyzed by Stable Radical-Containing MOFs: Improved Efficiency Induced by a Structural Transformation.

Herein we present a new viologen-based radical-containing metal-organic framework (RMOF) Gd-IHEP-7, which upon heating in air undergoes a single-crystal-to-single-crystal transformation to generate Gd-IHEP-8. Both RMOFs exhibit excellent air and water stability as a result of favorable radical-radical interactions, and their long-lifetime radicals result in wide spectral absorption in the range 200-2500 nm. Gd-IHEP-7 and Gd-IHEP-8 show excellent activity toward solar-driven nitrogen fixation, with ammonia production rates of 128 and 220 µmol h-1 g-1 , respectively. Experiments and theoretical calculations indicate that both RMOFs have similar nitrogen fixation pathways. The enhanced catalytic efficiency of Gd-IHEP-8 versus Gd-IHEP-7 is attributed to intermediates stabilized by enhanced hydrogen bonding.

Quality of Life After Oral Cancer Resection and Free Flap Reconstruction.

PURPOSE: This study focused on quality of life for patients in northeast China who underwent oral cancer resection directly before flap reconstruction. In addition, this study compared differences among the radial forearm free flap (RFFF), ulnar forearm free flap (UFFF), and anterolateral thigh flap (ALTF) for defect reconstruction. MATERIALS AND METHODS: To assess patients' quality of life, the University of Washington Quality of Life and 14-item Oral Health Impact Profile (OHIP-14) questionnaires were completed 6 months after reconstruction. RESULTS: The flap size of the ALTF group was much larger than that of the UFFF and RFFF groups. The appearance score of the ALTF group was markedly higher than that of the UFFF and RFFF groups, whereas these groups had a much higher swallowing score than the ALTF group. Furthermore, the ALTF group had much lower social disability OHIP-14 scores than the RFFF group. CONCLUSIONS: The results indicate that all 3 reconstruction methods are similar, but that the ALTF has a slight advantage over the UFFF and RFFF.

Miniplates Versus Reconstruction Plates in Vascularized Osteocutaneous Flap Reconstruction of the Mandible.

PURPOSE: The main aim of this article is to compare the complication rate associated with the use of miniplates versus reconstruction plates in vascularized osteocutaneous flap reconstruction of the mandible. PATIENTS AND METHODS: The authors searched PubMed, Web of Science, EMBASE, Chinese BioMedical Literature Database (CBM), Cochrane Library, and clinicaltrials.gov up to September 2017 to identify studies that compared the complication rate of miniplates versus reconstruction plates in patients undergoing mandibular reconstruction. Two reviewers individually extracted the data and performed a quality assessment. Plate exposure, plate fracture/removal, infection, and overall complications were evaluated. RESULTS: Five studies with 511 cases were included in our analysis. No significant difference was found between the groups. However, the reconstruction plate led to fewer overall complications and plate exposure postoperatively than did the miniplate. CONCLUSION: Our meta-analysis suggests that miniplates and reconstruction plates are suitable for mandibular reconstruction with a vascularized osteocutaneous flap.

The application of fibular free flap with flexor hallucis longus in maxilla or mandible extensive defect: a comparison study with conventional flap.

BACKGROUND: The repair and reconstruction of maxillary and mandibular extensive defects have put huge challenges to surgeons. The fibular free flap (FFF) is one of the standard treatment choices for reconstruction. The conventional FFF has deficiencies, such as forming poor oral mucosa, limited flap tissue, and perforator vessel variation. To improve the use of FFF, we add the flexor hallucis longus (FHL) in the flap (FHL-FFF). In this paper, we described the advantage and indication of FHL-FFF and conducted a retrospective study to compare FHL-FFF and FFF without FHL. METHODS: Fifty-four patients who underwent FFF were enrolled and divided into two groups: nFHL group (using FFF without FHL, 38 patients) and FHL group (using FHL-FFF, 16 patients). The perioperative clinical data of patients was collected and analyzed. RESULTS: The flaps all survived in two groups. We mainly used FHL to fill dead space, and the donor-site morbidity was slight. In FHL group, flap harvesting time was shorter (118.63 ± 11.76 vs 125.74 ± 11.33 min, P = 0.042), the size of flap's skin paddle was smaller (16.5 (0-96) vs 21.0(10-104) cm2, P = 0.027) than nFHL group. There were no significant differences (P > 0.05) in hospital days, hospitalization expense, rate of perioperative complications, etc. between the two groups. Compared with FFF without FHL, FHL-FFF will neither affect the use of flap nor bring more problems. CONCLUSION: The FHL-FFF simplifies the flap harvesting operation. The FHL can form good mucosa and make FFF rely less on skin paddle. It can be used for adding flap tissue and dealing with perforator vessel variation in reconstruction of maxillary and mandibular extensive defects.

Elderly population have a decreased aneurysmal subarachnoid hemorrhage incidence rate than Middle aged population: a descriptive analysis of 8,144 cases in mainland China.

PURPOSE: Rupture of an intracranial aneurysm is a life-threatening acute cerebrovascular event. The purpose of this study was to investigate whether aneurysmal subarachnoid haemorrhage (SAH) incidence rate is higher or lower in elderly population than in middle aged population. MATERIALS AND METHODS: Aneurysmal SAH cases were collected retrospectively from the archives of 21 hospitals in Mainland China. All the cases were collected from September 2016 and backward consecutively for a period of time up to 8 years. SAH was initially diagnosed by brain computed tomography (CT). CT angiography (CTA) or digital subtraction angiography (DSA) was followed and SAH was confirmed to be due to cerebral aneurysm rupture. For cases when multiple bleeding occurred, the age of the first SAH was used in this study. The total incidence from all hospitals at each age group were summed together for females and males respectively; then adjusted by the total population number at each age group for females and males which was from the 2010 population census of the People's Republic of China. RESULTS: In total there were 8,144 cases of intracranial aneurysmal SAH, with 4,861 females and 3,283 males. For females the relative aneurysmal SAH incidence rate started to decrease after around 65 years old, while for males the relative aneurysmal SAH incidence rate started to decrease after around 53 years old. CONCLUSION: Our data tentatively suggest elderly patients may be at a reduced risk of rupture compared with patients who are younger while have similar other risk factors.

Reconstruction of Complex Total Parotidectomy Defect With a Chimeric Anterolateral Thigh Perforator Flap and Vascularized Motor Branch of Femoral Nerve Grafting.

Reconstruction of complex total parotidectomy defects after ablation is always a challenge for surgeons. The surgical technique in reconstructing total parotidectomy defects using an anterolateral thigh (ALT) flap has not been described in detail. This report describes the treatment of a difficult case with a complex total parotidectomy defect. An ALT flap composed of a vascularized motor branch of the femoral nerve and a narrow portion of the vastus lateralis muscle was harvested. An 8-cm-long vascularized nerve was transplanted into the gap, which can be considered a cable transplant graft, and a myocutaneous paddle was used to cover and fill in the soft tissue defect. There were no complications after surgery, and the patient was satisfied with the reconstructed facial contours. This case shows that using a chimeric ALT flap for reconstruction is possible in a complex total parotidectomy defect.

Transverse cervical vessels as recipient vessels in oral and maxillofacial microsurgical reconstruction after former operations with or without radiotherapy.

BACKGROUND: The purpose of this study was to investigate the reliability and outcome of using the transverse cervical vessel (TCV) as a recipient vessel for microvascular reconstruction in patients whose vessels in the neck region are unavailable because of previous surgery or radiotherapy. METHODS: Between January 2012 and August 2014, secondary head and neck reconstruction was performed using the TCV as a recipient vessel in eight patients who had undergone previous neck dissection and radiation therapy (n = 5). Five patients had a recurrent carcinoma, one had undergone an operation for scar release and two had been treated surgically for a second primary cancer. The anterolateral thigh flap (ALT), anteromedial thigh flap (AMT), and fibular flap were used for the reconstruction. Clinical data were recorded for each patient. RESULTS: All of the ipsilateral transverse cervical arteries were found to be free of disease. The second free flap was revascularized using the TCVs (n = 6) or the external (n = 1) or internal (n = 1) jugular vein. The free flaps used for the reconstruction included the ALT flap (n = 6), AMT flap (n = 2), and fibular flap (n = 1). All of the flaps survived without vascular events, and the patients healed without major complications. The mean follow-up time was 11 months. One patient died of distant metastases during follow-up. CONCLUSIONS: In patients who have previously undergone neck surgery with or without radiotherapy, the TCVs are reliable and easily accessible recipient vessels for microsurgical reconstruction in the oral and maxillofacial region. If the transverse cervical vein is unavailable, the internal or external jugular vein should be dissected carefully to serve as an alternative for microvascular anastomoses.

Submental versus platysma flap for the reconstruction of complex facial defects following resection of head and neck tumors.

OBJECTIVE: To compare the platysma flap with submental flap in terms of tumor and flap characteristics, operative properties and the functional outcomes. METHODS: A total of 65 patients presented with tumors of head and neck and underwent curative tumor resection with different neck dissections at the Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology of China Medical University; from March 2005 to December 2012 were included in the study. After radical tumor excision and neck dissection the resultant complex defects were reconstructed with either platysma flap or the submental flap. The extent of surgical resection, the type of neck dissection and choice of flap reconstruction was at the discretion of the surgical team. The functional outcomes, operative time and characteristics of both platysma and submental flaps were compared and the statistical tests of significance were applied accordingly. RESULTS: The mean age was 60 years. The complex facial defects of 30 patients were reconstructed with platysma flap and of 35 patients with submental flap. Mean operation time of submental flap including flap harvesting (5.58±1.96hrs) was shorter than platysma flap (6.2±1.4hrs). The majority of the flaps (88-93%) were taken successfully in both groups. Submental flap was associated with significantly higher patients' satisfaction regarding acceptable functional outcomes (p-value 0.027). The mean reduction in mouth opening was significantly smaller in platysma group (0.37 ±0.18cms) than the submental group (0.47±0.16). CONCLUSION: This study demonstrates that both platysma and submental flap techniques can be used for the reconstruction of complex facial defects with the acceptable functional outcome. The platysma flap can be harvested to medium size defects up to 70cm(2) with good mouth opening. The submental flap is simpler, faster with a wider range of application and more acceptable functional outcomes.

Clinical reliability of radial forearm free flap in repair of buccal defects.

BACKGROUND: The ideal method for buccal defects should provide good outcome of both function and appearance; our goal is to highlight the reliability of radial forearm flap in buccal reconstruction. METHODS: A retrospective study was conducted. From 2005 to 2012, 20 radial forearm flaps were used to repair the defects. We analyzed the superiority and reliability of the flap; in addition, we reviewed some related literature and made a comparison between radial forearm flap and platysma flap. RESULTS: All radial forearm flaps totally survived, but two flaps suffered venous obstruction, hematoma, respectively. Radial forearm flap preserved the original interincisal distance well. In our follow-up, all patients had sufficient mouth-opening width (mean: 4.3 cm). CONCLUSION: Radial forearm flap is a reliable method for buccal defect reconstruction.

Nonadiabatic Dynamics of Polaron Hopping and Coupling with Water on Reduced TiO2.

By interplay between first-principles molecular dynamics and nonadiabatic molecular dynamics simulations based on the decoherence-induced surface-hopping approach, we investigate and quantify the mechanisms through which different electron polaron hopping regimes in the reduced anatase TiO2(101) surface influence recombination of photogenerated charge carriers, also in the presence of adsorbed water (H2O) molecules. The simulations reveal that fast hopping regimes promote ultrafast recombination of photogenerated charge-carriers. Conversely, charge recombination is delayed in the presence of slower polaron hopping and even more so if the polaron is pinned at one Ti-site, as typical following adsorption of H2O on the anatase(101) surface. These trends are related to the observed enhancement of the space and energy overlap between conduction band minimum and polaron band gap states, and the ensuing nonadiabatic couplings (NAC) strengths, during a polaronic hop. We expect these insights on the beneficial role of polaron diffusion pinning for the extended lifetime of photoexcitations in TiO2 to sustain ongoing developments of photocatalytic strategies based on this substrate.

Comparing donor site morbidity between radial and ulnar forearm free flaps: a meta-analysis.

The vascularised forearm free flap is a workhorse flap for the reconstruction of many types of soft tissue defects. However, the difference in donor-site morbidity between the radial forearm free flap (RFFF) and ulnar forearm free flap (UFFF) remains controversial. This study aimed to compare the donor-site outcomes of RFFF and UFFF. We searched PubMed, EMBASE, Web of Science, clinicaltrials.gov, Cochrane Library, and Chinese Biomedical Literature Database up to August 10, 2021, to identify studies on donor-site outcomes of RFFF versus UFFF in patients undergoing reconstructive surgery. Two authors individually extracted data and performed quality assessments of the selected articles. The overall morbidity and overall effect of individual complications of the donor site were analysed. In total, 288 cases from five studies were included in our analysis. The UFFF group was significantly superior to the RFFF group regarding overall morbidity and overall effect of individual complications of the donor site. The morbidity of UFFF donor sites was significantly lower than that of RFFF, and UFFF may be an ideal substitute for RFFF in reconstructive surgery. However, additional large-scale studies are necessary to confirm this finding.

Risk Factors for Free Flap Outcomes: A Retrospective Study of 318 Free Flaps for Head and Neck Defect Reconstruction.

OBJECTIVES: This study was conducted to identify the risk factors for free flap outcomes in head and neck reconstruction. METHODS: A retrospective review of 318 free flaps were used for head and neck reconstructions in 317 patients over seven years. The patient characteristics, surgical data, and flap outcomes were recorded. The impact of risk factors related on the outcomes of free flaps were analyzed using single and multivariate analysis. RESULTS: For single factor analysis, 295 free flaps for the first reconstruction were included. Hypertension and the type of recipient vein are associated with venous thrombosis (P = .018, P = .047). Hypertension, type of free flap, recipient artery, and recipient vein were associated with the incidence of re-exploration (P = .009, P = .011, P = .017, P = .021). Hypertension had an obvious effect on the flap survival (P = .005). For multivariate analysis, hypertension (odds ratio = .166, 95% confidence interval: .043 - .636; P = .009) was a statistically significant risk factor for flap survival. For types of recipient artery and vein, selecting two venous anastomosis (one of IJVS and one of EJVS) had the minimum incidence of venous thrombosis (2.2%), and selecting facial artery, single vein (one of IJVS), and two veins (one of IJVS and one of EJVS) for anastomosis had lower incidence of re-exploration, which were 4.4%, 2.9%, and 6.0%, respectively (P < .05). CONCLUSIONS: Risk factors as hypertension, type of free flap, recipient artery and vein should be paid more attention in the free flaps for head and neck reconstructions. We believe proper measures will lead to better results in head and neck reconstruction.

The versatile application of cervicofacial and cervicothoracic rotation flaps in head and neck surgery.

BACKGROUND: The large defects resulting from head and neck tumour surgeries present a reconstructive challenge to surgeons. Although numerous methods can be used, they all have their own limitations. In this paper, we present our experience with cervicofacial and cervicothoracic rotation flaps to help expand the awareness and application of this useful system of flaps. METHODS: Twenty-one consecutive patients who underwent repair of a variety of defects of the head and neck with cervicofacial or cervicothoracic flaps in our hospital from 2006 to 2009 were retrospectively analysed. Statistics pertaining to the patients' clinical factors were gathered. RESULTS: Cheek neoplasms are the most common indication for cervicofacial and cervicothoracic rotation flaps, followed by parotid tumours. Among the 12 patients with medical comorbidities, the most common was hypertension. Defects ranging from 1.5 cm × 1.5 cm to 7 cm × 6 cm were reconstructed by cervicofacial flap, and defects from 3 cm × 2 cm to 16 cm × 7 cm were reconstructed by cervicothoracic flap. The two flaps also exhibited versatility in these reconstructions. When combined with the pectoralis major myocutaneous flap, the cervicothoracic flap could repair through-and-through cheek defects, and in combination with a temporalis myofacial flap, the cervicofacial flap was able to cover orbital defects. Additionally, 95% patients were satisfied with their resulting contour results. CONCLUSIONS: Cervicofacial and cervicothoracic flaps provide a technically simple, reliable, safe, efficient and cosmetic means to reconstruct defects of the head and neck.

Free posterior tibial artery perforator flap for floor of mouth reconstruction: a case report.

In this report, we present a case with floor of mouth squamous cell carcinoma who underwent wide excision of tumor, a marginal mandibulectomy and bilateral selective neck dissections. A 7 cm × 4 cm fasciocutaneous flap based on a posterior tibial artery perforator (PTAP) from the left posterior leg was harvested to reconstruct a floor of the mouth defect. The donor-site defect was closed primarily. The flap survived in its entirety. No donor or recipient site complications occurred. The patient tolerated a regular diet at 3-month follow-up with normal speech and leg function. To our knowledge, there has been no previous report on the use of the PTAP flap for floor of mouth reconstruction. Our experience has shown the PTAP flap could be one of options for small defects.

Unprecedented neptunyl(V) cation-directed structural variations in Np2Ox compounds.

Studies on transuranic oxides provide a particularly valuable insight into chemical bonding in actinide compounds, in which subtle differences between metal ions and oxygen atoms are of fundamental importance for the stability of these compounds as well as their existence. In the case of neptunium, it is still mainly limited to specific Np oxide compounds without periodicity in the formation of stable structures or different oxidation states. Here, we report a systematic global minimum search of Np2Ox (x = 1-7) clusters and the computational study of their electronic structures and chemical bonding. These studies suggest that Np(V) ion could play the structure-directing role, and thus the mixed-valent Np(III/V) in Np2O4 is predicted accessible. In comparison with lower oxidation state Np analogues, significant 5f-orbital covalent interactions with Np(V)O bonding are observed, which shows that these model neptunium oxides can provide new understandings into the behavior of 5f-electrons in chemical bonding and structural design.