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Xenetic Biosciences, Inc. – ‘10-K’ for 12/31/22 – ‘EX-101.DEF’

On:  Wednesday, 3/22/23, at 4:30pm ET   ·   For:  12/31/22   ·   Accession #:  1683168-23-1674   ·   File #:  1-37937

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  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 3/22/23  Xenetic Biosciences, Inc.         10-K       12/31/22   74:6.6M                                   GlobalOne Filings Inc/FA

Annual Report   —   Form 10-K

Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-K        Annual Report                                       HTML   1.40M 
 2: EX-3.14     Certificate of Amendment to Articles of             HTML     32K 
                Incorporation                                                    
 3: EX-4.1      Description of the Registrant S Securities          HTML     32K 
 4: EX-21.1     Subsidiaries of Registrant                          HTML     19K 
 5: EX-23.1     Independent Registered Public Accounting Firm       HTML     19K 
                Consent                                                          
 6: EX-31.1     Certification of Principal Executive Officer        HTML     24K 
 7: EX-31.2     Certification of Principal Financial Officer        HTML     24K 
 8: EX-32.1     Certification -- §906 - SOA'02                      HTML     20K 
14: R1          Cover                                               HTML     90K 
15: R2          Consolidated Balance Sheets                         HTML    103K 
16: R3          Consolidated Balance Sheets (Parenthetical)         HTML     43K 
17: R4          Consolidated Statements of Comprehensive Loss       HTML     62K 
18: R5          Consolidated Statements of Comprehensive Loss       HTML     37K 
                (Parenthetical)                                                  
19: R6          Consolidated Statements of Stockholders' Equity     HTML     73K 
20: R7          Consolidated Statements of Cash Flows               HTML     84K 
21: R8          The Company                                         HTML     28K 
22: R9          Risks and Uncertainties                             HTML     25K 
23: R10         Summary of Significant Accounting Policies          HTML     74K 
24: R11         Significant Strategic Collaborations                HTML     47K 
25: R12         Licensing Arrangements                              HTML     34K 
26: R13         Property and Equipment, net                         HTML     31K 
27: R14         Other Assets                                        HTML     24K 
28: R15         Accrued Expenses                                    HTML     27K 
29: R16         Fair Value Measurements                             HTML     26K 
30: R17         Income Taxes                                        HTML     74K 
31: R18         Stockholders? Equity                                HTML     82K 
32: R19         Share-Based Expense                                 HTML    129K 
33: R20         Employee Benefit Plans                              HTML     25K 
34: R21         Commitments and Contingencies                       HTML     36K 
35: R22         Related Party Transactions                          HTML     37K 
36: R23         Subsequent Events                                   HTML     27K 
37: R24         Summary of Significant Accounting Policies          HTML    124K 
                (Policies)                                                       
38: R25         Summary of Significant Accounting Policies          HTML     24K 
                (Tables)                                                         
39: R26         Property and Equipment, net (Tables)                HTML     29K 
40: R27         Accrued Expenses (Tables)                           HTML     26K 
41: R28         Income Taxes (Tables)                               HTML     60K 
42: R29         Share-Based Expense (Tables)                        HTML    124K 
43: R30         Commitments and Contingencies (Tables)              HTML     31K 
44: R31         Summary of Significant Accounting Policies          HTML     27K 
                (Details)                                                        
45: R32         Summary of Significant Accounting Policies          HTML     31K 
                (Details Narrative)                                              
46: R33         Significant Strategic Collaborations (Details       HTML     65K 
                Narrative)                                                       
47: R34         Licensing Arrangements (Details Narrative)          HTML     50K 
48: R35         Property and Equipment, net (Details)               HTML     33K 
49: R36         Property and Equipment, net (Details Narrative)     HTML     22K 
50: R37         Other Assets (Details Narrative)                    HTML     24K 
51: R38         Accrued Expenses (Details)                          HTML     30K 
52: R39         Fair Value Measurements (Details Narrative)         HTML     25K 
53: R40         Income Taxes (Details - Income by geographic        HTML     37K 
                regions)                                                         
54: R41         Income Taxes (Details - Tax reconcilation)          HTML     45K 
55: R42         Income Taxes (Details - Deferred Tax Assets)        HTML     60K 
56: R43         Income Taxes (Details Narrative)                    HTML     40K 
57: R44         Stockholders? Equity (Details Narrative)            HTML    143K 
58: R45         Share-Based Expense (Details - Share based          HTML     27K 
                expense)                                                         
59: R46         Share-Based Expense (Details - Assumptions          HTML     41K 
                Employee)                                                        
60: R47         Share-Based Expense (Details - Employee option      HTML     71K 
                activity)                                                        
61: R48         Share-Based Expense (Details - Non-Vested employee  HTML     47K 
                Option activity)                                                 
62: R49         Share-Based Expense (Details - Non-employee option  HTML     71K 
                activity)                                                        
63: R50         Share-Based Expense (Details - Common stock         HTML     37K 
                awards)                                                          
64: R51         Share-Based Expense (Details Narrative)             HTML     69K 
65: R52         Employee Benefit Plans (Details Narrative)          HTML     25K 
66: R53         Commitments and Contingencies (Details - Cash flow  HTML     22K 
                Information)                                                     
67: R54         Commitments and Contingencies (Details - lease      HTML     23K 
                information)                                                     
68: R55         Commitments and Contingencies (Details Narrative)   HTML     33K 
69: R56         Related Party Transactions (Details Narrative)      HTML     40K 
72: XML         IDEA XML File -- Filing Summary                      XML    128K 
70: XML         XBRL Instance -- xenetic_i10k-123122_htm             XML   1.10M 
71: EXCEL       IDEA Workbook of Financial Reports                  XLSX    132K 
10: EX-101.CAL  XBRL Calculations -- xbio-20221231_cal               XML    125K 
11: EX-101.DEF  XBRL Definitions -- xbio-20221231_def                XML    614K 
12: EX-101.LAB  XBRL Labels -- xbio-20221231_lab                     XML    822K 
13: EX-101.PRE  XBRL Presentations -- xbio-20221231_pre              XML    744K 
 9: EX-101.SCH  XBRL Schema -- xbio-20221231                         XSD    132K 
73: JSON        XBRL Instance as JSON Data -- MetaLinks              385±   557K 
74: ZIP         XBRL Zipped Folder -- 0001683168-23-001674-xbrl      Zip    416K 


‘EX-101.DEF’   —   XBRL Definitions — xbio-20221231_def


This Exhibit is an XBRL XML File.


                                                                                                                                                                                
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1 Subsequent Filing that References this Filing

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 3/21/24  Xenetic Biosciences, Inc.         10-K       12/31/23   71:5.6M                                   GlobalOne Filings Inc/FA


34 Previous Filings that this Filing References

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 8/11/22  Xenetic Biosciences, Inc.         10-Q        6/30/22   50:3.2M                                   GlobalOne Filings Inc/FA
 3/22/22  Xenetic Biosciences, Inc.         10-K       12/31/21   75:6M                                     GlobalOne Filings Inc/FA
11/19/21  Xenetic Biosciences, Inc.         8-K:1,9    11/19/21   13:520K                                   GlobalOne Filings Inc/FA
11/16/21  Xenetic Biosciences, Inc.         8-K:1,9    11/15/21   12:281K                                   GlobalOne Filings Inc/FA
10/15/21  Xenetic Biosciences, Inc.         DEF 14A    12/07/21    1:601K                                   GlobalOne Filings Inc/FA
 7/28/21  Xenetic Biosciences, Inc.         8-K:1,3,7   7/26/21    7:701K                                   GlobalOne Filings Inc/FA
 3/16/21  Xenetic Biosciences, Inc.         10-K       12/31/20   78:5.1M                                   GlobalOne Filings Inc/FA
 8/12/20  Xenetic Biosciences, Inc.         10-Q        6/30/20   51:2.2M                                   GlobalOne Filings Inc/FA
 3/26/20  Xenetic Biosciences, Inc.         10-K       12/31/19   79:4.9M                                   GlobalOne Filings Inc/FA
 7/22/19  Xenetic Biosciences, Inc.         8-K:1,3,5,8 7/17/19    6:932K                                   GlobalOne Filings Inc/FA
 7/16/19  Xenetic Biosciences, Inc.         8-K:9       7/16/19    2:91K                                    GlobalOne Filings Inc/FA
 7/16/19  Xenetic Biosciences, Inc.         8-K:1,9     7/15/19    3:45K                                    GlobalOne Filings Inc/FA
 6/25/19  Xenetic Biosciences, Inc.         8-K:1,3,9   6/24/19    3:202K                                   GlobalOne Filings Inc/FA
 6/24/19  Xenetic Biosciences, Inc.         8-K:1,3,5   6/19/19    6:96K                                    GlobalOne Filings Inc/FA
 6/13/19  Xenetic Biosciences, Inc.         8-K:1,8,9   6/07/19    3:56K                                    GlobalOne Filings Inc/FA
 5/20/19  Xenetic Biosciences, Inc.         8-K/A:8,9   3/01/19    2:428K                                   GlobalOne Filings Inc/FA
 3/30/18  Xenetic Biosciences, Inc.         10-K       12/31/17   85:5.1M                                   GlobalOne Filings Inc/FA
 8/14/17  Xenetic Biosciences, Inc.         10-Q        6/30/17   46:1.5M                                   GlobalOne Filings Inc/FA
 4/04/17  Xenetic Biosciences, Inc.         8-K:3,5,7,9 4/04/17    4:280K                                   GlobalOne Filings Inc/FA
 2/27/17  Xenetic Biosciences, Inc.         8-K:5,9     2/27/17    2:171K                                   Feather Filings LLC/FA
 1/04/17  Xenetic Biosciences, Inc.         8-K:5,7,8,9 1/01/17    3:777K                                   Feather Filings LLC/FA
12/06/16  Xenetic Biosciences, Inc.         8-K:5,7,9  12/02/16    3:279K                                   Feather Filings LLC/FA
10/27/16  Xenetic Biosciences, Inc.         S-1/A      10/26/16   98:6.7M                                   GlobalOne Filings Inc/FA
10/11/16  Xenetic Biosciences, Inc.         S-1/A                 99:7.1M                                   GlobalOne Filings Inc/FA
 7/14/16  Xenetic Biosciences, Inc.         S-1/A                  5:661K                                   Publicease Inc./FA
11/16/15  Xenetic Biosciences, Inc.         8-K:1,2,3,811/13/15   13:1.2M                                   Publicease Inc./FA
 9/30/15  Xenetic Biosciences, Inc.         8-K:5,9     9/24/15    2:23K                                    Westward Law LLC/FA
 7/08/15  Xenetic Biosciences, Inc.         8-K:8,9     7/03/15    9:1M                                     Publicease Inc./FA
 4/15/15  Xenetic Biosciences, Inc.         10-K       12/31/14   74:5.9M                                   Publicease Inc./FA
 2/18/15  Xenetic Biosciences, Inc.         10-K/A     12/31/13   22:4.8M                                   Publicease Inc./FA
 1/10/14  Xenetic Biosciences, Inc.         10-Q       11/30/13   40:1.2M                                   Timber Pharmas, Inc.
 2/27/13  Xenetic Biosciences, Inc.         8-K:5,8,9   2/25/13    2:19K                                    Clark Corp Law Group LLP
 2/12/13  Xenetic Biosciences, Inc.         8-K:2,5     2/11/13    2:24K                                    Clark Corp Law Group LLP
11/21/11  Xenetic Biosciences, Inc.         S-1                    7:607K
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Filing Submission 0001683168-23-001674   –   Alternative Formats (Word / Rich Text, HTML, Plain Text, et al.)

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